Qiyue

(James)Zhang

Anusha Verankki

bull Lesion detection through palpation bull This is not applicable in the detection of smaller internal

abnormal tissues bull invention of the MRI in 1970s the idea was around since

1930s bull Late 1990s MRE is invented by clinic doctors and

scientists at Mayo Clinic as an alternative detection of liver biopsy

bull Using an MRI quantitatively to image and characterize the viscoelastic properties of tissue in vivo

bull More efficient comfortable safer faster and less expensive than biopsy

bull today this is used to detect lesion tissue (cancer fibrosis) in liver heart brain and skeletal muscle

History of MRE

2

Why MRE

Most of the conventional

medical imaging techniques

(CT MRI and US) are not

capable of depicting

properties assessed by

palpation(like stiffness of

tissue)

Property assessed by

palpation is called Elastic

Modulus Elastic modulus

gives information on

palpation on a much larger

scale than CT US and MRI

3

4

5

Magnetic resonance Elastography

Excitation application ‐dynamic (vibrations) image the propagation of

s‐waves produced by the excitation of the tissue

Measurement of Tissue response to Applied Stress MRI

Mechanical parameter estimation acquiring data to estimate the mechanical properties of

the tissue Quantitative and qualitative data are recorded to produce an elastogram

6

How does it work

7

1

Generating mechanical waves in the tissue

2

Acquiring MR images depicting the propagation of the waves

3

The resulting data are processed to generate quantitative images

displaying the stiffness of tissue

8

Deforming the target

S‐wave

‐one of the two main typesof elastic

body waves

‐The S‐wave moves as ashear or

transverse wave

‐Shear wave propagationin biological tissue isrelated to stiffness

9

How to generate S‐wave

Oscillating transducer(actuator)

‐MR safety‐MR compatibility

‐3 types of mechanical drivers ElectromagneticPiezoelectricFocused‐ultrasound‐

based

10

Electromagnetic actuator

11

Piezoelectric actuator

12

13

How to detect deformation

Phase‐contrast MRI‐

motion‐

sensitizing gradient

‐

Phase shift in received MR signal

14

Mechanical model

Mechanical properties of

tissue

‐first Lame constant(λ)

‐second Lame constant(μ)

‐bulk modulus K

= λ

+ (2 3)μ

‐Poissonrsquos ratio(v)

‐Youngrsquos modulus(E

15

Harmonic motion model

Helmholtzinversion

21 independent parameters

required

16

17

18

Applications Liver fibrosis

Causes hepatic diseases chronic Hepatitis C ALD

( alcoholic liver disease) fatty liver disease autoimmune

hepatitis

Response to injury scar formation But in fibrosis the

healing process goes wrong

Fibrosis is the accumulation of tough fibrous scar tissue in the

liver

Fibrosis

if left untreated leads to cirrhosis

Other imaging methods (CT MRI) are very limited in

detecting fibrosis before it has advanced to irreversible

cirrhosis

19

20

Using MRE

21

Patient A

normal liverMean shear

stiffness of

21kPa

Patient BHepatic

steatosis and

mild fibrosis 48 kPa

Patient CChronic liver

disease L most

areasgt 8kPa in

shear stiffness

22

MRE vs Biopsy

Highly accurate in detecting liver fibrosis

Much more efficient than a liver biopsy there

is a chance of underestimation of hepatic fibrosis by about 20 to 30‐

sampling error

94 to 97 accuracy

Most patients tend to delay taking a biopsy

since it is an invasive procedure

The earlier the hepatologist knows the

sooner the treatment can be given 23

Brain MR Elastography

Brain elasticity data can be used to detect certain diffuse diseases of the brain that are not well evaluated

by conventional imaging methods ‐Alzheimers‐Hydrocephalus‐focal brain lesions‐Multiple Sclerosis‐obtaining quantitative measurements of Elastic

modulus of cerebral tissue is of interest in biomechanical studies of brain trauma and in the

development of neurosurgery simulation techniques

24

MRE system designed for the brain

lsquoArsquo

applies vertical

displacement to the head

lsquoBrsquo

applies horizontal

displacement to the head

via a bite block

The θ

between the two can

be varied to image the

waves at various stages of

propagation

25

MRE system for a brain

Technical Challenges bullIntroducing s‐waves through the bony calvariumbullPerforming efficient sampling and processing of a 3D displacement field

Developed using a soft pillow like(passive) vibration (50 Hz) source to produce

intracranial s‐waves

26

Hydrocephalus

Obstruction of CSF flow in either

the lateral ventricles or the

subarachnoid space

Results in an increased size of

ventricles and therefore an

increase in intracranial pressure

(ICP)

MRI and CT assist in diagnosis

but they have limitations

These techniques only detect

ventricular enlargement which

can be confused with cerebral

atrophy or periventricular

leukomalacia (shrinkage of

periventricular white matter)

27

MRE diagnosis

Top normal patientBottom patient with hydrocephalus

28

MRE for detection of Cardiac disease states

HFPEF heart failure due to preserved ejection fraction

Hypertrophic cardiomyopathy

Load independent contractility

MI Myocardial infarction

29

Heart failure due to preserved Ejection fraction

30

HFpEf

Preserved ejection fraction

Efgt50

40 to 70 of heart failure

cases

Heart is contracting normally

but the ventricle walls are

stiff and do not relax

properly Less blood is

entering the heart during

systole

Patients with pEf also had

hypertension and coronary

artery diseases

31

Stiffness results

32

Future directions

Mechanical driver‐wave frequency‐multiple driver source

Data Processing

‐encoding process‐high‐speed 3D imaging‐new mathematical model for estimation of

tissue properties

33

References

Mauduca A Dynamic Magnetic Resonance Elastography Mayo Clinic College of

Medicine

Araoz

P Kolipaka

A mayo Clinic (Producer) (2010)Cardiac MRE [Web Video]

Retrieved from httpwwwyoutubecomwatchv=NyvjE5DpIis

Bachir T (2009)

Advanced MRI methods for assessment of chronic liver disease

Ehman R L (2009) Magnetic Resonance Elastography An emerging Tool for

Cellular Mechanobiology Mayo Clinic Rochester MN USA

Grenier

D Milot

L Peng

X Pilluel

F Beuf

O (2007) A Magnetic Resonance

Elastography

approach for liver investigationProceedings

for 29th

Annual

International Conference of the IEEE EMBS Lyon France

HighleyMan L Franciscus A (2011) Disease progression What is fibrosis

Hepatitis C Support Project Retrieved from

httpwwwhcvadvocateorghepatitisfactsheets_pdfFibrosispdf

Juergen

Braun Karl Braun and Ingolf

Sack Electromagnetic Actuator for

Generating Variably Oriented Shear Waves in MR Elastogrphy Magnetic

Resonance in Medicine 50220‐222(2003)

Kolipaka

A

Araoz

PA

McGee

KP Manduca

A

Ehman

RL (2010) Magnetic

resonance elastography

as a method for the assessment of effective myocardial

stiffness throughout the cardiac cycle

pubMed Retrieved from

httpwwwncbinlmnihgovpubmed20578052

McGee KP Lake D Mariappan

Y HubmayrRD Manduca

A Ansell K and Ehman

RL Calculation of shear

stiffness in noise dominated magnetic resonance elastography

data based on

principal frequency estimation 2011

Phys Med Biol

56

4291 34

bull Lesion detection through palpation bull This is not applicable in the detection of smaller internal

abnormal tissues bull invention of the MRI in 1970s the idea was around since

1930s bull Late 1990s MRE is invented by clinic doctors and

scientists at Mayo Clinic as an alternative detection of liver biopsy

bull Using an MRI quantitatively to image and characterize the viscoelastic properties of tissue in vivo

bull More efficient comfortable safer faster and less expensive than biopsy

bull today this is used to detect lesion tissue (cancer fibrosis) in liver heart brain and skeletal muscle

History of MRE

2

Why MRE

Most of the conventional

medical imaging techniques

(CT MRI and US) are not

capable of depicting

properties assessed by

palpation(like stiffness of

tissue)

Property assessed by

palpation is called Elastic

Modulus Elastic modulus

gives information on

palpation on a much larger

scale than CT US and MRI

3

4

5

Magnetic resonance Elastography

Excitation application ‐dynamic (vibrations) image the propagation of

s‐waves produced by the excitation of the tissue

Measurement of Tissue response to Applied Stress MRI

Mechanical parameter estimation acquiring data to estimate the mechanical properties of

the tissue Quantitative and qualitative data are recorded to produce an elastogram

6

How does it work

7

1

Generating mechanical waves in the tissue

2

Acquiring MR images depicting the propagation of the waves

3

The resulting data are processed to generate quantitative images

displaying the stiffness of tissue

8

Deforming the target

S‐wave

‐one of the two main typesof elastic

body waves

‐The S‐wave moves as ashear or

transverse wave

‐Shear wave propagationin biological tissue isrelated to stiffness

9

How to generate S‐wave

Oscillating transducer(actuator)

‐MR safety‐MR compatibility

‐3 types of mechanical drivers ElectromagneticPiezoelectricFocused‐ultrasound‐

based

10

Electromagnetic actuator

11

Piezoelectric actuator

12

13

How to detect deformation

Phase‐contrast MRI‐

motion‐

sensitizing gradient

‐

Phase shift in received MR signal

14

Mechanical model

Mechanical properties of

tissue

‐first Lame constant(λ)

‐second Lame constant(μ)

‐bulk modulus K

= λ

+ (2 3)μ

‐Poissonrsquos ratio(v)

‐Youngrsquos modulus(E

15

Harmonic motion model

Helmholtzinversion

21 independent parameters

required

16

17

18

Applications Liver fibrosis

Causes hepatic diseases chronic Hepatitis C ALD

( alcoholic liver disease) fatty liver disease autoimmune

hepatitis

Response to injury scar formation But in fibrosis the

healing process goes wrong

Fibrosis is the accumulation of tough fibrous scar tissue in the

liver

Fibrosis

if left untreated leads to cirrhosis

Other imaging methods (CT MRI) are very limited in

detecting fibrosis before it has advanced to irreversible

cirrhosis

19

20

Using MRE

21

Patient A

normal liverMean shear

stiffness of

21kPa

Patient BHepatic

steatosis and

mild fibrosis 48 kPa

Patient CChronic liver

disease L most

areasgt 8kPa in

shear stiffness

22

MRE vs Biopsy

Highly accurate in detecting liver fibrosis

Much more efficient than a liver biopsy there

is a chance of underestimation of hepatic fibrosis by about 20 to 30‐

sampling error

94 to 97 accuracy

Most patients tend to delay taking a biopsy

since it is an invasive procedure

The earlier the hepatologist knows the

sooner the treatment can be given 23

Brain MR Elastography

Brain elasticity data can be used to detect certain diffuse diseases of the brain that are not well evaluated

by conventional imaging methods ‐Alzheimers‐Hydrocephalus‐focal brain lesions‐Multiple Sclerosis‐obtaining quantitative measurements of Elastic

modulus of cerebral tissue is of interest in biomechanical studies of brain trauma and in the

development of neurosurgery simulation techniques

24

MRE system designed for the brain

lsquoArsquo

applies vertical

displacement to the head

lsquoBrsquo

applies horizontal

displacement to the head

via a bite block

The θ

between the two can

be varied to image the

waves at various stages of

propagation

25

MRE system for a brain

Technical Challenges bullIntroducing s‐waves through the bony calvariumbullPerforming efficient sampling and processing of a 3D displacement field

Developed using a soft pillow like(passive) vibration (50 Hz) source to produce

intracranial s‐waves

26

Hydrocephalus

Obstruction of CSF flow in either

the lateral ventricles or the

subarachnoid space

Results in an increased size of

ventricles and therefore an

increase in intracranial pressure

(ICP)

MRI and CT assist in diagnosis

but they have limitations

These techniques only detect

ventricular enlargement which

can be confused with cerebral

atrophy or periventricular

leukomalacia (shrinkage of

periventricular white matter)

27

MRE diagnosis

Top normal patientBottom patient with hydrocephalus

28

MRE for detection of Cardiac disease states

HFPEF heart failure due to preserved ejection fraction

Hypertrophic cardiomyopathy

Load independent contractility

MI Myocardial infarction

29

Heart failure due to preserved Ejection fraction

30

HFpEf

Preserved ejection fraction

Efgt50

40 to 70 of heart failure

cases

Heart is contracting normally

but the ventricle walls are

stiff and do not relax

properly Less blood is

entering the heart during

systole

Patients with pEf also had

hypertension and coronary

artery diseases

31

Stiffness results

32

Future directions

Mechanical driver‐wave frequency‐multiple driver source

Data Processing

‐encoding process‐high‐speed 3D imaging‐new mathematical model for estimation of

tissue properties

33

References

Mauduca A Dynamic Magnetic Resonance Elastography Mayo Clinic College of

Medicine

Araoz

P Kolipaka

A mayo Clinic (Producer) (2010)Cardiac MRE [Web Video]

Retrieved from httpwwwyoutubecomwatchv=NyvjE5DpIis

Bachir T (2009)

Advanced MRI methods for assessment of chronic liver disease

Ehman R L (2009) Magnetic Resonance Elastography An emerging Tool for

Cellular Mechanobiology Mayo Clinic Rochester MN USA

Grenier

D Milot

L Peng

X Pilluel

F Beuf

O (2007) A Magnetic Resonance

Elastography

approach for liver investigationProceedings

for 29th

Annual

International Conference of the IEEE EMBS Lyon France

HighleyMan L Franciscus A (2011) Disease progression What is fibrosis

Hepatitis C Support Project Retrieved from

httpwwwhcvadvocateorghepatitisfactsheets_pdfFibrosispdf

Juergen

Braun Karl Braun and Ingolf

Sack Electromagnetic Actuator for

Generating Variably Oriented Shear Waves in MR Elastogrphy Magnetic

Resonance in Medicine 50220‐222(2003)

Kolipaka

A

Araoz

PA

McGee

KP Manduca

A

Ehman

RL (2010) Magnetic

resonance elastography

as a method for the assessment of effective myocardial

stiffness throughout the cardiac cycle

pubMed Retrieved from

httpwwwncbinlmnihgovpubmed20578052

McGee KP Lake D Mariappan

Y HubmayrRD Manduca

A Ansell K and Ehman

RL Calculation of shear

stiffness in noise dominated magnetic resonance elastography

data based on

principal frequency estimation 2011

Phys Med Biol

56

4291 34

Why MRE

Most of the conventional

medical imaging techniques

(CT MRI and US) are not

capable of depicting

properties assessed by

palpation(like stiffness of

tissue)

Property assessed by

palpation is called Elastic

Modulus Elastic modulus

gives information on

palpation on a much larger

scale than CT US and MRI

3

4

5

Magnetic resonance Elastography

Excitation application ‐dynamic (vibrations) image the propagation of

s‐waves produced by the excitation of the tissue

Measurement of Tissue response to Applied Stress MRI

Mechanical parameter estimation acquiring data to estimate the mechanical properties of

the tissue Quantitative and qualitative data are recorded to produce an elastogram

6

How does it work

7

1

Generating mechanical waves in the tissue

2

Acquiring MR images depicting the propagation of the waves

3

The resulting data are processed to generate quantitative images

displaying the stiffness of tissue

8

Deforming the target

S‐wave

‐one of the two main typesof elastic

body waves

‐The S‐wave moves as ashear or

transverse wave

‐Shear wave propagationin biological tissue isrelated to stiffness

9

How to generate S‐wave

Oscillating transducer(actuator)

‐MR safety‐MR compatibility

‐3 types of mechanical drivers ElectromagneticPiezoelectricFocused‐ultrasound‐

based

10

Electromagnetic actuator

11

Piezoelectric actuator

12

13

How to detect deformation

Phase‐contrast MRI‐

motion‐

sensitizing gradient

‐

Phase shift in received MR signal

14

Mechanical model

Mechanical properties of

tissue

‐first Lame constant(λ)

‐second Lame constant(μ)

‐bulk modulus K

= λ

+ (2 3)μ

‐Poissonrsquos ratio(v)

‐Youngrsquos modulus(E

15

Harmonic motion model

Helmholtzinversion

21 independent parameters

required

16

17

18

Applications Liver fibrosis

Causes hepatic diseases chronic Hepatitis C ALD

( alcoholic liver disease) fatty liver disease autoimmune

hepatitis

Response to injury scar formation But in fibrosis the

healing process goes wrong

Fibrosis is the accumulation of tough fibrous scar tissue in the

liver

Fibrosis

if left untreated leads to cirrhosis

Other imaging methods (CT MRI) are very limited in

detecting fibrosis before it has advanced to irreversible

cirrhosis

19

20

Using MRE

21

Patient A

normal liverMean shear

stiffness of

21kPa

Patient BHepatic

steatosis and

mild fibrosis 48 kPa

Patient CChronic liver

disease L most

areasgt 8kPa in

shear stiffness

22

MRE vs Biopsy

Highly accurate in detecting liver fibrosis

Much more efficient than a liver biopsy there

is a chance of underestimation of hepatic fibrosis by about 20 to 30‐

sampling error

94 to 97 accuracy

Most patients tend to delay taking a biopsy

since it is an invasive procedure

The earlier the hepatologist knows the

sooner the treatment can be given 23

Brain MR Elastography

Brain elasticity data can be used to detect certain diffuse diseases of the brain that are not well evaluated

by conventional imaging methods ‐Alzheimers‐Hydrocephalus‐focal brain lesions‐Multiple Sclerosis‐obtaining quantitative measurements of Elastic

modulus of cerebral tissue is of interest in biomechanical studies of brain trauma and in the

development of neurosurgery simulation techniques

24

MRE system designed for the brain

lsquoArsquo

applies vertical

displacement to the head

lsquoBrsquo

applies horizontal

displacement to the head

via a bite block

The θ

between the two can

be varied to image the

waves at various stages of

propagation

25

MRE system for a brain

Technical Challenges bullIntroducing s‐waves through the bony calvariumbullPerforming efficient sampling and processing of a 3D displacement field

Developed using a soft pillow like(passive) vibration (50 Hz) source to produce

intracranial s‐waves

26

Hydrocephalus

Obstruction of CSF flow in either

the lateral ventricles or the

subarachnoid space

Results in an increased size of

ventricles and therefore an

increase in intracranial pressure

(ICP)

MRI and CT assist in diagnosis

but they have limitations

These techniques only detect

ventricular enlargement which

can be confused with cerebral

atrophy or periventricular

leukomalacia (shrinkage of

periventricular white matter)

27

MRE diagnosis

Top normal patientBottom patient with hydrocephalus

28

MRE for detection of Cardiac disease states

HFPEF heart failure due to preserved ejection fraction

Hypertrophic cardiomyopathy

Load independent contractility

MI Myocardial infarction

29

Heart failure due to preserved Ejection fraction

30

HFpEf

Preserved ejection fraction

Efgt50

40 to 70 of heart failure

cases

Heart is contracting normally

but the ventricle walls are

stiff and do not relax

properly Less blood is

entering the heart during

systole

Patients with pEf also had

hypertension and coronary

artery diseases

31

Stiffness results

32

Future directions

Mechanical driver‐wave frequency‐multiple driver source

Data Processing

‐encoding process‐high‐speed 3D imaging‐new mathematical model for estimation of

tissue properties

33

References

Mauduca A Dynamic Magnetic Resonance Elastography Mayo Clinic College of

Medicine

Araoz

P Kolipaka

A mayo Clinic (Producer) (2010)Cardiac MRE [Web Video]

Retrieved from httpwwwyoutubecomwatchv=NyvjE5DpIis

Bachir T (2009)

Advanced MRI methods for assessment of chronic liver disease

Ehman R L (2009) Magnetic Resonance Elastography An emerging Tool for

Cellular Mechanobiology Mayo Clinic Rochester MN USA

Grenier

D Milot

L Peng

X Pilluel

F Beuf

O (2007) A Magnetic Resonance

Elastography

approach for liver investigationProceedings

for 29th

Annual

International Conference of the IEEE EMBS Lyon France

HighleyMan L Franciscus A (2011) Disease progression What is fibrosis

Hepatitis C Support Project Retrieved from

httpwwwhcvadvocateorghepatitisfactsheets_pdfFibrosispdf

Juergen

Braun Karl Braun and Ingolf

Sack Electromagnetic Actuator for

Generating Variably Oriented Shear Waves in MR Elastogrphy Magnetic

Resonance in Medicine 50220‐222(2003)

Kolipaka

A

Araoz

PA

McGee

KP Manduca

A

Ehman

RL (2010) Magnetic

resonance elastography

as a method for the assessment of effective myocardial

stiffness throughout the cardiac cycle

pubMed Retrieved from

httpwwwncbinlmnihgovpubmed20578052

McGee KP Lake D Mariappan

Y HubmayrRD Manduca

A Ansell K and Ehman

RL Calculation of shear

stiffness in noise dominated magnetic resonance elastography

data based on

principal frequency estimation 2011

Phys Med Biol

56

4291 34

4

5

Magnetic resonance Elastography

Excitation application ‐dynamic (vibrations) image the propagation of

s‐waves produced by the excitation of the tissue

Measurement of Tissue response to Applied Stress MRI

Mechanical parameter estimation acquiring data to estimate the mechanical properties of

the tissue Quantitative and qualitative data are recorded to produce an elastogram

6

How does it work

7

1

Generating mechanical waves in the tissue

2

Acquiring MR images depicting the propagation of the waves

3

The resulting data are processed to generate quantitative images

displaying the stiffness of tissue

8

Deforming the target

S‐wave

‐one of the two main typesof elastic

body waves

‐The S‐wave moves as ashear or

transverse wave

‐Shear wave propagationin biological tissue isrelated to stiffness

9

How to generate S‐wave

Oscillating transducer(actuator)

‐MR safety‐MR compatibility

‐3 types of mechanical drivers ElectromagneticPiezoelectricFocused‐ultrasound‐

based

10

Electromagnetic actuator

11

Piezoelectric actuator

12

13

How to detect deformation

Phase‐contrast MRI‐

motion‐

sensitizing gradient

‐

Phase shift in received MR signal

14

Mechanical model

Mechanical properties of

tissue

‐first Lame constant(λ)

‐second Lame constant(μ)

‐bulk modulus K

= λ

+ (2 3)μ

‐Poissonrsquos ratio(v)

‐Youngrsquos modulus(E

15

Harmonic motion model

Helmholtzinversion

21 independent parameters

required

16

17

18

Applications Liver fibrosis

Causes hepatic diseases chronic Hepatitis C ALD

( alcoholic liver disease) fatty liver disease autoimmune

hepatitis

Response to injury scar formation But in fibrosis the

healing process goes wrong

Fibrosis is the accumulation of tough fibrous scar tissue in the

liver

Fibrosis

if left untreated leads to cirrhosis

Other imaging methods (CT MRI) are very limited in

detecting fibrosis before it has advanced to irreversible

cirrhosis

19

20

Using MRE

21

Patient A

normal liverMean shear

stiffness of

21kPa

Patient BHepatic

steatosis and

mild fibrosis 48 kPa

Patient CChronic liver

disease L most

areasgt 8kPa in

shear stiffness

22

MRE vs Biopsy

Highly accurate in detecting liver fibrosis

Much more efficient than a liver biopsy there

is a chance of underestimation of hepatic fibrosis by about 20 to 30‐

sampling error

94 to 97 accuracy

Most patients tend to delay taking a biopsy

since it is an invasive procedure

The earlier the hepatologist knows the

sooner the treatment can be given 23

Brain MR Elastography

Brain elasticity data can be used to detect certain diffuse diseases of the brain that are not well evaluated

by conventional imaging methods ‐Alzheimers‐Hydrocephalus‐focal brain lesions‐Multiple Sclerosis‐obtaining quantitative measurements of Elastic

modulus of cerebral tissue is of interest in biomechanical studies of brain trauma and in the

development of neurosurgery simulation techniques

24

MRE system designed for the brain

lsquoArsquo

applies vertical

displacement to the head

lsquoBrsquo

applies horizontal

displacement to the head

via a bite block

The θ

between the two can

be varied to image the

waves at various stages of

propagation

25

MRE system for a brain

Technical Challenges bullIntroducing s‐waves through the bony calvariumbullPerforming efficient sampling and processing of a 3D displacement field

Developed using a soft pillow like(passive) vibration (50 Hz) source to produce

intracranial s‐waves

26

Hydrocephalus

Obstruction of CSF flow in either

the lateral ventricles or the

subarachnoid space

Results in an increased size of

ventricles and therefore an

increase in intracranial pressure

(ICP)

MRI and CT assist in diagnosis

but they have limitations

These techniques only detect

ventricular enlargement which

can be confused with cerebral

atrophy or periventricular

leukomalacia (shrinkage of

periventricular white matter)

27

MRE diagnosis

Top normal patientBottom patient with hydrocephalus

28

MRE for detection of Cardiac disease states

HFPEF heart failure due to preserved ejection fraction

Hypertrophic cardiomyopathy

Load independent contractility

MI Myocardial infarction

29

Heart failure due to preserved Ejection fraction

30

HFpEf

Preserved ejection fraction

Efgt50

40 to 70 of heart failure

cases

Heart is contracting normally

but the ventricle walls are

stiff and do not relax

properly Less blood is

entering the heart during

systole

Patients with pEf also had

hypertension and coronary

artery diseases

31

Stiffness results

32

Future directions

Mechanical driver‐wave frequency‐multiple driver source

Data Processing

‐encoding process‐high‐speed 3D imaging‐new mathematical model for estimation of

tissue properties

33

References

Mauduca A Dynamic Magnetic Resonance Elastography Mayo Clinic College of

Medicine

Araoz

P Kolipaka

A mayo Clinic (Producer) (2010)Cardiac MRE [Web Video]

Retrieved from httpwwwyoutubecomwatchv=NyvjE5DpIis

Bachir T (2009)

Advanced MRI methods for assessment of chronic liver disease

Ehman R L (2009) Magnetic Resonance Elastography An emerging Tool for

Cellular Mechanobiology Mayo Clinic Rochester MN USA

Grenier

D Milot

L Peng

X Pilluel

F Beuf

O (2007) A Magnetic Resonance

Elastography

approach for liver investigationProceedings

for 29th

Annual

International Conference of the IEEE EMBS Lyon France

HighleyMan L Franciscus A (2011) Disease progression What is fibrosis

Hepatitis C Support Project Retrieved from

httpwwwhcvadvocateorghepatitisfactsheets_pdfFibrosispdf

Juergen

Braun Karl Braun and Ingolf

Sack Electromagnetic Actuator for

Generating Variably Oriented Shear Waves in MR Elastogrphy Magnetic

Resonance in Medicine 50220‐222(2003)

Kolipaka

A

Araoz

PA

McGee

KP Manduca

A

Ehman

RL (2010) Magnetic

resonance elastography

as a method for the assessment of effective myocardial

stiffness throughout the cardiac cycle

pubMed Retrieved from

httpwwwncbinlmnihgovpubmed20578052

McGee KP Lake D Mariappan

Y HubmayrRD Manduca

A Ansell K and Ehman

RL Calculation of shear

stiffness in noise dominated magnetic resonance elastography

data based on

principal frequency estimation 2011

Phys Med Biol

56

4291 34

5

Magnetic resonance Elastography

Excitation application ‐dynamic (vibrations) image the propagation of

s‐waves produced by the excitation of the tissue

Measurement of Tissue response to Applied Stress MRI

Mechanical parameter estimation acquiring data to estimate the mechanical properties of

the tissue Quantitative and qualitative data are recorded to produce an elastogram

6

How does it work

7

1

Generating mechanical waves in the tissue

2

Acquiring MR images depicting the propagation of the waves

3

The resulting data are processed to generate quantitative images

displaying the stiffness of tissue

8

Deforming the target

S‐wave

‐one of the two main typesof elastic

body waves

‐The S‐wave moves as ashear or

transverse wave

‐Shear wave propagationin biological tissue isrelated to stiffness

9

How to generate S‐wave

Oscillating transducer(actuator)

‐MR safety‐MR compatibility

‐3 types of mechanical drivers ElectromagneticPiezoelectricFocused‐ultrasound‐

based

10

Electromagnetic actuator

11

Piezoelectric actuator

12

13

How to detect deformation

Phase‐contrast MRI‐

motion‐

sensitizing gradient

‐

Phase shift in received MR signal

14

Mechanical model

Mechanical properties of

tissue

‐first Lame constant(λ)

‐second Lame constant(μ)

‐bulk modulus K

= λ

+ (2 3)μ

‐Poissonrsquos ratio(v)

‐Youngrsquos modulus(E

15

Harmonic motion model

Helmholtzinversion

21 independent parameters

required

16

17

18

Applications Liver fibrosis

Causes hepatic diseases chronic Hepatitis C ALD

( alcoholic liver disease) fatty liver disease autoimmune

hepatitis

Response to injury scar formation But in fibrosis the

healing process goes wrong

Fibrosis is the accumulation of tough fibrous scar tissue in the

liver

Fibrosis

if left untreated leads to cirrhosis

Other imaging methods (CT MRI) are very limited in

detecting fibrosis before it has advanced to irreversible

cirrhosis

19

20

Using MRE

21

Patient A

normal liverMean shear

stiffness of

21kPa

Patient BHepatic

steatosis and

mild fibrosis 48 kPa

Patient CChronic liver

disease L most

areasgt 8kPa in

shear stiffness

22

MRE vs Biopsy

Highly accurate in detecting liver fibrosis

Much more efficient than a liver biopsy there

is a chance of underestimation of hepatic fibrosis by about 20 to 30‐

sampling error

94 to 97 accuracy

Most patients tend to delay taking a biopsy

since it is an invasive procedure

The earlier the hepatologist knows the

sooner the treatment can be given 23

Brain MR Elastography

Brain elasticity data can be used to detect certain diffuse diseases of the brain that are not well evaluated

by conventional imaging methods ‐Alzheimers‐Hydrocephalus‐focal brain lesions‐Multiple Sclerosis‐obtaining quantitative measurements of Elastic

modulus of cerebral tissue is of interest in biomechanical studies of brain trauma and in the

development of neurosurgery simulation techniques

24

MRE system designed for the brain

lsquoArsquo

applies vertical

displacement to the head

lsquoBrsquo

applies horizontal

displacement to the head

via a bite block

The θ

between the two can

be varied to image the

waves at various stages of

propagation

25

MRE system for a brain

Technical Challenges bullIntroducing s‐waves through the bony calvariumbullPerforming efficient sampling and processing of a 3D displacement field

Developed using a soft pillow like(passive) vibration (50 Hz) source to produce

intracranial s‐waves

26

Hydrocephalus

Obstruction of CSF flow in either

the lateral ventricles or the

subarachnoid space

Results in an increased size of

ventricles and therefore an

increase in intracranial pressure

(ICP)

MRI and CT assist in diagnosis

but they have limitations

These techniques only detect

ventricular enlargement which

can be confused with cerebral

atrophy or periventricular

leukomalacia (shrinkage of

periventricular white matter)

27

MRE diagnosis

Top normal patientBottom patient with hydrocephalus

28

MRE for detection of Cardiac disease states

HFPEF heart failure due to preserved ejection fraction

Hypertrophic cardiomyopathy

Load independent contractility

MI Myocardial infarction

29

Heart failure due to preserved Ejection fraction

30

HFpEf

Preserved ejection fraction

Efgt50

40 to 70 of heart failure

cases

Heart is contracting normally

but the ventricle walls are

stiff and do not relax

properly Less blood is

entering the heart during

systole

Patients with pEf also had

hypertension and coronary

artery diseases

31

Stiffness results

32

Future directions

Mechanical driver‐wave frequency‐multiple driver source

Data Processing

‐encoding process‐high‐speed 3D imaging‐new mathematical model for estimation of

tissue properties

33

References

Mauduca A Dynamic Magnetic Resonance Elastography Mayo Clinic College of

Medicine

Araoz

P Kolipaka

A mayo Clinic (Producer) (2010)Cardiac MRE [Web Video]

Retrieved from httpwwwyoutubecomwatchv=NyvjE5DpIis

Bachir T (2009)

Advanced MRI methods for assessment of chronic liver disease

Ehman R L (2009) Magnetic Resonance Elastography An emerging Tool for

Cellular Mechanobiology Mayo Clinic Rochester MN USA

Grenier

D Milot

L Peng

X Pilluel

F Beuf

O (2007) A Magnetic Resonance

Elastography

approach for liver investigationProceedings

for 29th

Annual

International Conference of the IEEE EMBS Lyon France

HighleyMan L Franciscus A (2011) Disease progression What is fibrosis

Hepatitis C Support Project Retrieved from

httpwwwhcvadvocateorghepatitisfactsheets_pdfFibrosispdf

Juergen

Braun Karl Braun and Ingolf

Sack Electromagnetic Actuator for

Generating Variably Oriented Shear Waves in MR Elastogrphy Magnetic

Resonance in Medicine 50220‐222(2003)

Kolipaka

A

Araoz

PA

McGee

KP Manduca

A

Ehman

RL (2010) Magnetic

resonance elastography

as a method for the assessment of effective myocardial

stiffness throughout the cardiac cycle

pubMed Retrieved from

httpwwwncbinlmnihgovpubmed20578052

McGee KP Lake D Mariappan

Y HubmayrRD Manduca

A Ansell K and Ehman

RL Calculation of shear

stiffness in noise dominated magnetic resonance elastography

data based on

principal frequency estimation 2011

Phys Med Biol

56

4291 34

Magnetic resonance Elastography

Excitation application ‐dynamic (vibrations) image the propagation of

s‐waves produced by the excitation of the tissue

Measurement of Tissue response to Applied Stress MRI

Mechanical parameter estimation acquiring data to estimate the mechanical properties of

the tissue Quantitative and qualitative data are recorded to produce an elastogram

6

How does it work

7

1

Generating mechanical waves in the tissue

2

Acquiring MR images depicting the propagation of the waves

3

The resulting data are processed to generate quantitative images

displaying the stiffness of tissue

8

Deforming the target

S‐wave

‐one of the two main typesof elastic

body waves

‐The S‐wave moves as ashear or

transverse wave

‐Shear wave propagationin biological tissue isrelated to stiffness

9

How to generate S‐wave

Oscillating transducer(actuator)

‐MR safety‐MR compatibility

‐3 types of mechanical drivers ElectromagneticPiezoelectricFocused‐ultrasound‐

based

10

Electromagnetic actuator

11

Piezoelectric actuator

12

13

How to detect deformation

Phase‐contrast MRI‐

motion‐

sensitizing gradient

‐

Phase shift in received MR signal

14

Mechanical model

Mechanical properties of

tissue

‐first Lame constant(λ)

‐second Lame constant(μ)

‐bulk modulus K

= λ

+ (2 3)μ

‐Poissonrsquos ratio(v)

‐Youngrsquos modulus(E

15

Harmonic motion model

Helmholtzinversion

21 independent parameters

required

16

17

18

Applications Liver fibrosis

Causes hepatic diseases chronic Hepatitis C ALD

( alcoholic liver disease) fatty liver disease autoimmune

hepatitis

Response to injury scar formation But in fibrosis the

healing process goes wrong

Fibrosis is the accumulation of tough fibrous scar tissue in the

liver

Fibrosis

if left untreated leads to cirrhosis

Other imaging methods (CT MRI) are very limited in

detecting fibrosis before it has advanced to irreversible

cirrhosis

19

20

Using MRE

21

Patient A

normal liverMean shear

stiffness of

21kPa

Patient BHepatic

steatosis and

mild fibrosis 48 kPa

Patient CChronic liver

disease L most

areasgt 8kPa in

shear stiffness

22

MRE vs Biopsy

Highly accurate in detecting liver fibrosis

Much more efficient than a liver biopsy there

is a chance of underestimation of hepatic fibrosis by about 20 to 30‐

sampling error

94 to 97 accuracy

Most patients tend to delay taking a biopsy

since it is an invasive procedure

The earlier the hepatologist knows the

sooner the treatment can be given 23

Brain MR Elastography

Brain elasticity data can be used to detect certain diffuse diseases of the brain that are not well evaluated

by conventional imaging methods ‐Alzheimers‐Hydrocephalus‐focal brain lesions‐Multiple Sclerosis‐obtaining quantitative measurements of Elastic

modulus of cerebral tissue is of interest in biomechanical studies of brain trauma and in the

development of neurosurgery simulation techniques

24

MRE system designed for the brain

lsquoArsquo

applies vertical

displacement to the head

lsquoBrsquo

applies horizontal

displacement to the head

via a bite block

The θ

between the two can

be varied to image the

waves at various stages of

propagation

25

MRE system for a brain

Technical Challenges bullIntroducing s‐waves through the bony calvariumbullPerforming efficient sampling and processing of a 3D displacement field

Developed using a soft pillow like(passive) vibration (50 Hz) source to produce

intracranial s‐waves

26

Hydrocephalus

Obstruction of CSF flow in either

the lateral ventricles or the

subarachnoid space

Results in an increased size of

ventricles and therefore an

increase in intracranial pressure

(ICP)

MRI and CT assist in diagnosis

but they have limitations

These techniques only detect

ventricular enlargement which

can be confused with cerebral

atrophy or periventricular

leukomalacia (shrinkage of

periventricular white matter)

27

MRE diagnosis

Top normal patientBottom patient with hydrocephalus

28

MRE for detection of Cardiac disease states

HFPEF heart failure due to preserved ejection fraction

Hypertrophic cardiomyopathy

Load independent contractility

MI Myocardial infarction

29

Heart failure due to preserved Ejection fraction

30

HFpEf

Preserved ejection fraction

Efgt50

40 to 70 of heart failure

cases

Heart is contracting normally

but the ventricle walls are

stiff and do not relax

properly Less blood is

entering the heart during

systole

Patients with pEf also had

hypertension and coronary

artery diseases

31

Stiffness results

32

Future directions

Mechanical driver‐wave frequency‐multiple driver source

Data Processing

‐encoding process‐high‐speed 3D imaging‐new mathematical model for estimation of

tissue properties

33

References

Mauduca A Dynamic Magnetic Resonance Elastography Mayo Clinic College of

Medicine

Araoz

P Kolipaka

A mayo Clinic (Producer) (2010)Cardiac MRE [Web Video]

Retrieved from httpwwwyoutubecomwatchv=NyvjE5DpIis

Bachir T (2009)

Advanced MRI methods for assessment of chronic liver disease

Ehman R L (2009) Magnetic Resonance Elastography An emerging Tool for

Cellular Mechanobiology Mayo Clinic Rochester MN USA

Grenier

D Milot

L Peng

X Pilluel

F Beuf

O (2007) A Magnetic Resonance

Elastography

approach for liver investigationProceedings

for 29th

Annual

International Conference of the IEEE EMBS Lyon France

HighleyMan L Franciscus A (2011) Disease progression What is fibrosis

Hepatitis C Support Project Retrieved from

httpwwwhcvadvocateorghepatitisfactsheets_pdfFibrosispdf

Juergen

Braun Karl Braun and Ingolf

Sack Electromagnetic Actuator for

Generating Variably Oriented Shear Waves in MR Elastogrphy Magnetic

Resonance in Medicine 50220‐222(2003)

Kolipaka

A

Araoz

PA

McGee

KP Manduca

A

Ehman

RL (2010) Magnetic

resonance elastography

as a method for the assessment of effective myocardial

stiffness throughout the cardiac cycle

pubMed Retrieved from

httpwwwncbinlmnihgovpubmed20578052

McGee KP Lake D Mariappan

Y HubmayrRD Manduca

A Ansell K and Ehman

RL Calculation of shear

stiffness in noise dominated magnetic resonance elastography

data based on

principal frequency estimation 2011

Phys Med Biol

56

4291 34

How does it work

7

1

Generating mechanical waves in the tissue

2

Acquiring MR images depicting the propagation of the waves

3

The resulting data are processed to generate quantitative images

displaying the stiffness of tissue

8

Deforming the target

S‐wave

‐one of the two main typesof elastic

body waves

‐The S‐wave moves as ashear or

transverse wave

‐Shear wave propagationin biological tissue isrelated to stiffness

9

How to generate S‐wave

Oscillating transducer(actuator)

‐MR safety‐MR compatibility

‐3 types of mechanical drivers ElectromagneticPiezoelectricFocused‐ultrasound‐

based

10

Electromagnetic actuator

11

Piezoelectric actuator

12

13

How to detect deformation

Phase‐contrast MRI‐

motion‐

sensitizing gradient

‐

Phase shift in received MR signal

14

Mechanical model

Mechanical properties of

tissue

‐first Lame constant(λ)

‐second Lame constant(μ)

‐bulk modulus K

= λ

+ (2 3)μ

‐Poissonrsquos ratio(v)

‐Youngrsquos modulus(E

15

Harmonic motion model

Helmholtzinversion

21 independent parameters

required

16

17

18

Applications Liver fibrosis

Causes hepatic diseases chronic Hepatitis C ALD

( alcoholic liver disease) fatty liver disease autoimmune

hepatitis

Response to injury scar formation But in fibrosis the

healing process goes wrong

Fibrosis is the accumulation of tough fibrous scar tissue in the

liver

Fibrosis

if left untreated leads to cirrhosis

Other imaging methods (CT MRI) are very limited in

detecting fibrosis before it has advanced to irreversible

cirrhosis

19

20

Using MRE

21

Patient A

normal liverMean shear

stiffness of

21kPa

Patient BHepatic

steatosis and

mild fibrosis 48 kPa

Patient CChronic liver

disease L most

areasgt 8kPa in

shear stiffness

22

MRE vs Biopsy

Highly accurate in detecting liver fibrosis

Much more efficient than a liver biopsy there

is a chance of underestimation of hepatic fibrosis by about 20 to 30‐

sampling error

94 to 97 accuracy

Most patients tend to delay taking a biopsy

since it is an invasive procedure

The earlier the hepatologist knows the

sooner the treatment can be given 23

Brain MR Elastography

Brain elasticity data can be used to detect certain diffuse diseases of the brain that are not well evaluated

by conventional imaging methods ‐Alzheimers‐Hydrocephalus‐focal brain lesions‐Multiple Sclerosis‐obtaining quantitative measurements of Elastic

modulus of cerebral tissue is of interest in biomechanical studies of brain trauma and in the

development of neurosurgery simulation techniques

24

MRE system designed for the brain

lsquoArsquo

applies vertical

displacement to the head

lsquoBrsquo

applies horizontal

displacement to the head

via a bite block

The θ

between the two can

be varied to image the

waves at various stages of

propagation

25

MRE system for a brain

Technical Challenges bullIntroducing s‐waves through the bony calvariumbullPerforming efficient sampling and processing of a 3D displacement field

Developed using a soft pillow like(passive) vibration (50 Hz) source to produce

intracranial s‐waves

26

Hydrocephalus

Obstruction of CSF flow in either

the lateral ventricles or the

subarachnoid space

Results in an increased size of

ventricles and therefore an

increase in intracranial pressure

(ICP)

MRI and CT assist in diagnosis

but they have limitations

These techniques only detect

ventricular enlargement which

can be confused with cerebral

atrophy or periventricular

leukomalacia (shrinkage of

periventricular white matter)

27

MRE diagnosis

Top normal patientBottom patient with hydrocephalus

28

MRE for detection of Cardiac disease states

HFPEF heart failure due to preserved ejection fraction

Hypertrophic cardiomyopathy

Load independent contractility

MI Myocardial infarction

29

Heart failure due to preserved Ejection fraction

30

HFpEf

Preserved ejection fraction

Efgt50

40 to 70 of heart failure

cases

Heart is contracting normally

but the ventricle walls are

stiff and do not relax

properly Less blood is

entering the heart during

systole

Patients with pEf also had

hypertension and coronary

artery diseases

31

Stiffness results

32

Future directions

Mechanical driver‐wave frequency‐multiple driver source

Data Processing

‐encoding process‐high‐speed 3D imaging‐new mathematical model for estimation of

tissue properties

33

References

Mauduca A Dynamic Magnetic Resonance Elastography Mayo Clinic College of

Medicine

Araoz

P Kolipaka

A mayo Clinic (Producer) (2010)Cardiac MRE [Web Video]

Retrieved from httpwwwyoutubecomwatchv=NyvjE5DpIis

Bachir T (2009)

Advanced MRI methods for assessment of chronic liver disease

Ehman R L (2009) Magnetic Resonance Elastography An emerging Tool for

Cellular Mechanobiology Mayo Clinic Rochester MN USA

Grenier

D Milot

L Peng

X Pilluel

F Beuf

O (2007) A Magnetic Resonance

Elastography

approach for liver investigationProceedings

for 29th

Annual

International Conference of the IEEE EMBS Lyon France

HighleyMan L Franciscus A (2011) Disease progression What is fibrosis

Hepatitis C Support Project Retrieved from

httpwwwhcvadvocateorghepatitisfactsheets_pdfFibrosispdf

Juergen

Braun Karl Braun and Ingolf

Sack Electromagnetic Actuator for

Generating Variably Oriented Shear Waves in MR Elastogrphy Magnetic

Resonance in Medicine 50220‐222(2003)

Kolipaka

A

Araoz

PA

McGee

KP Manduca

A

Ehman

RL (2010) Magnetic

resonance elastography

as a method for the assessment of effective myocardial

stiffness throughout the cardiac cycle

pubMed Retrieved from

httpwwwncbinlmnihgovpubmed20578052

McGee KP Lake D Mariappan

Y HubmayrRD Manduca

A Ansell K and Ehman

RL Calculation of shear

stiffness in noise dominated magnetic resonance elastography

data based on

principal frequency estimation 2011

Phys Med Biol

56

4291 34

1

Generating mechanical waves in the tissue

2

Acquiring MR images depicting the propagation of the waves

3

The resulting data are processed to generate quantitative images

displaying the stiffness of tissue

8

Deforming the target

S‐wave

‐one of the two main typesof elastic

body waves

‐The S‐wave moves as ashear or

transverse wave

‐Shear wave propagationin biological tissue isrelated to stiffness

9

How to generate S‐wave

Oscillating transducer(actuator)

‐MR safety‐MR compatibility

‐3 types of mechanical drivers ElectromagneticPiezoelectricFocused‐ultrasound‐

based

10

Electromagnetic actuator

11

Piezoelectric actuator

12

13

How to detect deformation

Phase‐contrast MRI‐

motion‐

sensitizing gradient

‐

Phase shift in received MR signal

14

Mechanical model

Mechanical properties of

tissue

‐first Lame constant(λ)

‐second Lame constant(μ)

‐bulk modulus K

= λ

+ (2 3)μ

‐Poissonrsquos ratio(v)

‐Youngrsquos modulus(E

15

Harmonic motion model

Helmholtzinversion

21 independent parameters

required

16

17

18

Applications Liver fibrosis

Causes hepatic diseases chronic Hepatitis C ALD

( alcoholic liver disease) fatty liver disease autoimmune

hepatitis

Response to injury scar formation But in fibrosis the

healing process goes wrong

Fibrosis is the accumulation of tough fibrous scar tissue in the

liver

Fibrosis

if left untreated leads to cirrhosis

Other imaging methods (CT MRI) are very limited in

detecting fibrosis before it has advanced to irreversible

cirrhosis

19

20

Using MRE

21

Patient A

normal liverMean shear

stiffness of

21kPa

Patient BHepatic

steatosis and

mild fibrosis 48 kPa

Patient CChronic liver

disease L most

areasgt 8kPa in

shear stiffness

22

MRE vs Biopsy

Highly accurate in detecting liver fibrosis

Much more efficient than a liver biopsy there

is a chance of underestimation of hepatic fibrosis by about 20 to 30‐

sampling error

94 to 97 accuracy

Most patients tend to delay taking a biopsy

since it is an invasive procedure

The earlier the hepatologist knows the

sooner the treatment can be given 23

Brain MR Elastography

Brain elasticity data can be used to detect certain diffuse diseases of the brain that are not well evaluated

by conventional imaging methods ‐Alzheimers‐Hydrocephalus‐focal brain lesions‐Multiple Sclerosis‐obtaining quantitative measurements of Elastic

modulus of cerebral tissue is of interest in biomechanical studies of brain trauma and in the

development of neurosurgery simulation techniques

24

MRE system designed for the brain

lsquoArsquo

applies vertical

displacement to the head

lsquoBrsquo

applies horizontal

displacement to the head

via a bite block

The θ

between the two can

be varied to image the

waves at various stages of

propagation

25

MRE system for a brain

Technical Challenges bullIntroducing s‐waves through the bony calvariumbullPerforming efficient sampling and processing of a 3D displacement field

Developed using a soft pillow like(passive) vibration (50 Hz) source to produce

intracranial s‐waves

26

Hydrocephalus

Obstruction of CSF flow in either

the lateral ventricles or the

subarachnoid space

Results in an increased size of

ventricles and therefore an

increase in intracranial pressure

(ICP)

MRI and CT assist in diagnosis

but they have limitations

These techniques only detect

ventricular enlargement which

can be confused with cerebral

atrophy or periventricular

leukomalacia (shrinkage of

periventricular white matter)

27

MRE diagnosis

Top normal patientBottom patient with hydrocephalus

28

MRE for detection of Cardiac disease states

HFPEF heart failure due to preserved ejection fraction

Hypertrophic cardiomyopathy

Load independent contractility

MI Myocardial infarction

29

Heart failure due to preserved Ejection fraction

30

HFpEf

Preserved ejection fraction

Efgt50

40 to 70 of heart failure

cases

Heart is contracting normally

but the ventricle walls are

stiff and do not relax

properly Less blood is

entering the heart during

systole

Patients with pEf also had

hypertension and coronary

artery diseases

31

Stiffness results

32

Future directions

Mechanical driver‐wave frequency‐multiple driver source

Data Processing

‐encoding process‐high‐speed 3D imaging‐new mathematical model for estimation of

tissue properties

33

References

Mauduca A Dynamic Magnetic Resonance Elastography Mayo Clinic College of

Medicine

Araoz

P Kolipaka

A mayo Clinic (Producer) (2010)Cardiac MRE [Web Video]

Retrieved from httpwwwyoutubecomwatchv=NyvjE5DpIis

Bachir T (2009)

Advanced MRI methods for assessment of chronic liver disease

Ehman R L (2009) Magnetic Resonance Elastography An emerging Tool for

Cellular Mechanobiology Mayo Clinic Rochester MN USA

Grenier

D Milot

L Peng

X Pilluel

F Beuf

O (2007) A Magnetic Resonance

Elastography

approach for liver investigationProceedings

for 29th

Annual

International Conference of the IEEE EMBS Lyon France

HighleyMan L Franciscus A (2011) Disease progression What is fibrosis

Hepatitis C Support Project Retrieved from

httpwwwhcvadvocateorghepatitisfactsheets_pdfFibrosispdf

Juergen

Braun Karl Braun and Ingolf

Sack Electromagnetic Actuator for

Generating Variably Oriented Shear Waves in MR Elastogrphy Magnetic

Resonance in Medicine 50220‐222(2003)

Kolipaka

A

Araoz

PA

McGee

KP Manduca

A

Ehman

RL (2010) Magnetic

resonance elastography

as a method for the assessment of effective myocardial

stiffness throughout the cardiac cycle

pubMed Retrieved from

httpwwwncbinlmnihgovpubmed20578052

McGee KP Lake D Mariappan

Y HubmayrRD Manduca

A Ansell K and Ehman

RL Calculation of shear

stiffness in noise dominated magnetic resonance elastography

data based on

principal frequency estimation 2011

Phys Med Biol

56

4291 34

Deforming the target

S‐wave

‐one of the two main typesof elastic

body waves

‐The S‐wave moves as ashear or

transverse wave

‐Shear wave propagationin biological tissue isrelated to stiffness

9

How to generate S‐wave

Oscillating transducer(actuator)

‐MR safety‐MR compatibility

‐3 types of mechanical drivers ElectromagneticPiezoelectricFocused‐ultrasound‐

based

10

Electromagnetic actuator

11

Piezoelectric actuator

12

13

How to detect deformation

Phase‐contrast MRI‐

motion‐

sensitizing gradient

‐

Phase shift in received MR signal

14

Mechanical model

Mechanical properties of

tissue

‐first Lame constant(λ)

‐second Lame constant(μ)

‐bulk modulus K

= λ

+ (2 3)μ

‐Poissonrsquos ratio(v)

‐Youngrsquos modulus(E

15

Harmonic motion model

Helmholtzinversion

21 independent parameters

required

16

17

18

Applications Liver fibrosis

Causes hepatic diseases chronic Hepatitis C ALD

( alcoholic liver disease) fatty liver disease autoimmune

hepatitis

Response to injury scar formation But in fibrosis the

healing process goes wrong

Fibrosis is the accumulation of tough fibrous scar tissue in the

liver

Fibrosis

if left untreated leads to cirrhosis

Other imaging methods (CT MRI) are very limited in

detecting fibrosis before it has advanced to irreversible

cirrhosis

19

20

Using MRE

21

Patient A

normal liverMean shear

stiffness of

21kPa

Patient BHepatic

steatosis and

mild fibrosis 48 kPa

Patient CChronic liver

disease L most

areasgt 8kPa in

shear stiffness

22

MRE vs Biopsy

Highly accurate in detecting liver fibrosis

Much more efficient than a liver biopsy there

is a chance of underestimation of hepatic fibrosis by about 20 to 30‐

sampling error

94 to 97 accuracy

Most patients tend to delay taking a biopsy

since it is an invasive procedure

The earlier the hepatologist knows the

sooner the treatment can be given 23

Brain MR Elastography

Brain elasticity data can be used to detect certain diffuse diseases of the brain that are not well evaluated

by conventional imaging methods ‐Alzheimers‐Hydrocephalus‐focal brain lesions‐Multiple Sclerosis‐obtaining quantitative measurements of Elastic

modulus of cerebral tissue is of interest in biomechanical studies of brain trauma and in the

development of neurosurgery simulation techniques

24

MRE system designed for the brain

lsquoArsquo

applies vertical

displacement to the head

lsquoBrsquo

applies horizontal

displacement to the head

via a bite block

The θ

between the two can

be varied to image the

waves at various stages of

propagation

25

MRE system for a brain

Technical Challenges bullIntroducing s‐waves through the bony calvariumbullPerforming efficient sampling and processing of a 3D displacement field

Developed using a soft pillow like(passive) vibration (50 Hz) source to produce

intracranial s‐waves

26

Hydrocephalus

Obstruction of CSF flow in either

the lateral ventricles or the

subarachnoid space

Results in an increased size of

ventricles and therefore an

increase in intracranial pressure

(ICP)

MRI and CT assist in diagnosis

but they have limitations

These techniques only detect

ventricular enlargement which

can be confused with cerebral

atrophy or periventricular

leukomalacia (shrinkage of

periventricular white matter)

27

MRE diagnosis

Top normal patientBottom patient with hydrocephalus

28

MRE for detection of Cardiac disease states

HFPEF heart failure due to preserved ejection fraction

Hypertrophic cardiomyopathy

Load independent contractility

MI Myocardial infarction

29

Heart failure due to preserved Ejection fraction

30

HFpEf

Preserved ejection fraction

Efgt50

40 to 70 of heart failure

cases

Heart is contracting normally

but the ventricle walls are

stiff and do not relax

properly Less blood is

entering the heart during

systole

Patients with pEf also had

hypertension and coronary

artery diseases

31

Stiffness results

32

Future directions

Mechanical driver‐wave frequency‐multiple driver source

Data Processing

‐encoding process‐high‐speed 3D imaging‐new mathematical model for estimation of

tissue properties

33

References

Mauduca A Dynamic Magnetic Resonance Elastography Mayo Clinic College of

Medicine

Araoz

P Kolipaka

A mayo Clinic (Producer) (2010)Cardiac MRE [Web Video]

Retrieved from httpwwwyoutubecomwatchv=NyvjE5DpIis

Bachir T (2009)

Advanced MRI methods for assessment of chronic liver disease

Ehman R L (2009) Magnetic Resonance Elastography An emerging Tool for

Cellular Mechanobiology Mayo Clinic Rochester MN USA

Grenier

D Milot

L Peng

X Pilluel

F Beuf

O (2007) A Magnetic Resonance

Elastography

approach for liver investigationProceedings

for 29th

Annual

International Conference of the IEEE EMBS Lyon France

HighleyMan L Franciscus A (2011) Disease progression What is fibrosis

Hepatitis C Support Project Retrieved from

httpwwwhcvadvocateorghepatitisfactsheets_pdfFibrosispdf

Juergen

Braun Karl Braun and Ingolf

Sack Electromagnetic Actuator for

Generating Variably Oriented Shear Waves in MR Elastogrphy Magnetic

Resonance in Medicine 50220‐222(2003)

Kolipaka

A

Araoz

PA

McGee

KP Manduca

A

Ehman

RL (2010) Magnetic

resonance elastography

as a method for the assessment of effective myocardial

stiffness throughout the cardiac cycle

pubMed Retrieved from

httpwwwncbinlmnihgovpubmed20578052

McGee KP Lake D Mariappan

Y HubmayrRD Manduca

A Ansell K and Ehman

RL Calculation of shear

stiffness in noise dominated magnetic resonance elastography

data based on

principal frequency estimation 2011

Phys Med Biol

56

4291 34

How to generate S‐wave

Oscillating transducer(actuator)

‐MR safety‐MR compatibility

‐3 types of mechanical drivers ElectromagneticPiezoelectricFocused‐ultrasound‐

based

10

Electromagnetic actuator

11

Piezoelectric actuator

12

13

How to detect deformation

Phase‐contrast MRI‐

motion‐

sensitizing gradient

‐

Phase shift in received MR signal

14

Mechanical model

Mechanical properties of

tissue

‐first Lame constant(λ)

‐second Lame constant(μ)

‐bulk modulus K

= λ

+ (2 3)μ

‐Poissonrsquos ratio(v)

‐Youngrsquos modulus(E

15

Harmonic motion model

Helmholtzinversion

21 independent parameters

required

16

17

18

Applications Liver fibrosis

Causes hepatic diseases chronic Hepatitis C ALD

( alcoholic liver disease) fatty liver disease autoimmune

hepatitis

Response to injury scar formation But in fibrosis the

healing process goes wrong

Fibrosis is the accumulation of tough fibrous scar tissue in the

liver

Fibrosis

if left untreated leads to cirrhosis

Other imaging methods (CT MRI) are very limited in

detecting fibrosis before it has advanced to irreversible

cirrhosis

19

20

Using MRE

21

Patient A

normal liverMean shear

stiffness of

21kPa

Patient BHepatic

steatosis and

mild fibrosis 48 kPa

Patient CChronic liver

disease L most

areasgt 8kPa in

shear stiffness

22

MRE vs Biopsy

Highly accurate in detecting liver fibrosis

Much more efficient than a liver biopsy there

is a chance of underestimation of hepatic fibrosis by about 20 to 30‐

sampling error

94 to 97 accuracy

Most patients tend to delay taking a biopsy

since it is an invasive procedure

The earlier the hepatologist knows the

sooner the treatment can be given 23

Brain MR Elastography

Brain elasticity data can be used to detect certain diffuse diseases of the brain that are not well evaluated

by conventional imaging methods ‐Alzheimers‐Hydrocephalus‐focal brain lesions‐Multiple Sclerosis‐obtaining quantitative measurements of Elastic

modulus of cerebral tissue is of interest in biomechanical studies of brain trauma and in the

development of neurosurgery simulation techniques

24

MRE system designed for the brain

lsquoArsquo

applies vertical

displacement to the head

lsquoBrsquo

applies horizontal

displacement to the head

via a bite block

The θ

between the two can

be varied to image the

waves at various stages of

propagation

25

MRE system for a brain

Technical Challenges bullIntroducing s‐waves through the bony calvariumbullPerforming efficient sampling and processing of a 3D displacement field

Developed using a soft pillow like(passive) vibration (50 Hz) source to produce

intracranial s‐waves

26

Hydrocephalus

Obstruction of CSF flow in either

the lateral ventricles or the

subarachnoid space

Results in an increased size of

ventricles and therefore an

increase in intracranial pressure

(ICP)

MRI and CT assist in diagnosis

but they have limitations

These techniques only detect

ventricular enlargement which

can be confused with cerebral

atrophy or periventricular

leukomalacia (shrinkage of

periventricular white matter)

27

MRE diagnosis

Top normal patientBottom patient with hydrocephalus

28

MRE for detection of Cardiac disease states

HFPEF heart failure due to preserved ejection fraction

Hypertrophic cardiomyopathy

Load independent contractility

MI Myocardial infarction

29

Heart failure due to preserved Ejection fraction

30

HFpEf

Preserved ejection fraction

Efgt50

40 to 70 of heart failure

cases

Heart is contracting normally

but the ventricle walls are

stiff and do not relax

properly Less blood is

entering the heart during

systole

Patients with pEf also had

hypertension and coronary

artery diseases

31

Stiffness results

32

Future directions

Mechanical driver‐wave frequency‐multiple driver source

Data Processing

‐encoding process‐high‐speed 3D imaging‐new mathematical model for estimation of

tissue properties

33

References

Mauduca A Dynamic Magnetic Resonance Elastography Mayo Clinic College of

Medicine

Araoz

P Kolipaka

A mayo Clinic (Producer) (2010)Cardiac MRE [Web Video]

Retrieved from httpwwwyoutubecomwatchv=NyvjE5DpIis

Bachir T (2009)

Advanced MRI methods for assessment of chronic liver disease

Ehman R L (2009) Magnetic Resonance Elastography An emerging Tool for

Cellular Mechanobiology Mayo Clinic Rochester MN USA

Grenier

D Milot

L Peng

X Pilluel

F Beuf

O (2007) A Magnetic Resonance

Elastography

approach for liver investigationProceedings

for 29th

Annual

International Conference of the IEEE EMBS Lyon France

HighleyMan L Franciscus A (2011) Disease progression What is fibrosis

Hepatitis C Support Project Retrieved from

httpwwwhcvadvocateorghepatitisfactsheets_pdfFibrosispdf

Juergen

Braun Karl Braun and Ingolf

Sack Electromagnetic Actuator for

Generating Variably Oriented Shear Waves in MR Elastogrphy Magnetic

Resonance in Medicine 50220‐222(2003)

Kolipaka

A

Araoz

PA

McGee

KP Manduca

A

Ehman

RL (2010) Magnetic

resonance elastography

as a method for the assessment of effective myocardial

stiffness throughout the cardiac cycle

pubMed Retrieved from

httpwwwncbinlmnihgovpubmed20578052

McGee KP Lake D Mariappan

Y HubmayrRD Manduca

A Ansell K and Ehman

RL Calculation of shear

stiffness in noise dominated magnetic resonance elastography

data based on

principal frequency estimation 2011

Phys Med Biol

56

4291 34

Electromagnetic actuator

11

Piezoelectric actuator

12

13

How to detect deformation

Phase‐contrast MRI‐

motion‐

sensitizing gradient

‐

Phase shift in received MR signal

14

Mechanical model

Mechanical properties of

tissue

‐first Lame constant(λ)

‐second Lame constant(μ)

‐bulk modulus K

= λ

+ (2 3)μ

‐Poissonrsquos ratio(v)

‐Youngrsquos modulus(E

15

Harmonic motion model

Helmholtzinversion

21 independent parameters

required

16

17

18

Applications Liver fibrosis

Causes hepatic diseases chronic Hepatitis C ALD

( alcoholic liver disease) fatty liver disease autoimmune

hepatitis

Response to injury scar formation But in fibrosis the

healing process goes wrong

Fibrosis is the accumulation of tough fibrous scar tissue in the

liver

Fibrosis

if left untreated leads to cirrhosis

Other imaging methods (CT MRI) are very limited in

detecting fibrosis before it has advanced to irreversible

cirrhosis

19

20

Using MRE

21

Patient A

normal liverMean shear

stiffness of

21kPa

Patient BHepatic

steatosis and

mild fibrosis 48 kPa

Patient CChronic liver

disease L most

areasgt 8kPa in

shear stiffness

22

MRE vs Biopsy

Highly accurate in detecting liver fibrosis

Much more efficient than a liver biopsy there

is a chance of underestimation of hepatic fibrosis by about 20 to 30‐

sampling error

94 to 97 accuracy

Most patients tend to delay taking a biopsy

since it is an invasive procedure

The earlier the hepatologist knows the

sooner the treatment can be given 23

Brain MR Elastography

Brain elasticity data can be used to detect certain diffuse diseases of the brain that are not well evaluated

by conventional imaging methods ‐Alzheimers‐Hydrocephalus‐focal brain lesions‐Multiple Sclerosis‐obtaining quantitative measurements of Elastic

modulus of cerebral tissue is of interest in biomechanical studies of brain trauma and in the

development of neurosurgery simulation techniques

24

MRE system designed for the brain

lsquoArsquo

applies vertical

displacement to the head

lsquoBrsquo

applies horizontal

displacement to the head

via a bite block

The θ

between the two can

be varied to image the

waves at various stages of

propagation

25

MRE system for a brain

Technical Challenges bullIntroducing s‐waves through the bony calvariumbullPerforming efficient sampling and processing of a 3D displacement field

Developed using a soft pillow like(passive) vibration (50 Hz) source to produce

intracranial s‐waves

26

Hydrocephalus

Obstruction of CSF flow in either

the lateral ventricles or the

subarachnoid space

Results in an increased size of

ventricles and therefore an

increase in intracranial pressure

(ICP)

MRI and CT assist in diagnosis

but they have limitations

These techniques only detect

ventricular enlargement which

can be confused with cerebral

atrophy or periventricular

leukomalacia (shrinkage of

periventricular white matter)

27

MRE diagnosis

Top normal patientBottom patient with hydrocephalus

28

MRE for detection of Cardiac disease states

HFPEF heart failure due to preserved ejection fraction

Hypertrophic cardiomyopathy

Load independent contractility

MI Myocardial infarction

29

Heart failure due to preserved Ejection fraction

30

HFpEf

Preserved ejection fraction

Efgt50

40 to 70 of heart failure

cases

Heart is contracting normally

but the ventricle walls are

stiff and do not relax

properly Less blood is

entering the heart during

systole

Patients with pEf also had

hypertension and coronary

artery diseases

31

Stiffness results

32

Future directions

Mechanical driver‐wave frequency‐multiple driver source

Data Processing

‐encoding process‐high‐speed 3D imaging‐new mathematical model for estimation of

tissue properties

33

References

Mauduca A Dynamic Magnetic Resonance Elastography Mayo Clinic College of

Medicine

Araoz

P Kolipaka

A mayo Clinic (Producer) (2010)Cardiac MRE [Web Video]

Retrieved from httpwwwyoutubecomwatchv=NyvjE5DpIis

Bachir T (2009)

Advanced MRI methods for assessment of chronic liver disease

Ehman R L (2009) Magnetic Resonance Elastography An emerging Tool for

Cellular Mechanobiology Mayo Clinic Rochester MN USA

Grenier

D Milot

L Peng

X Pilluel

F Beuf

O (2007) A Magnetic Resonance

Elastography

approach for liver investigationProceedings

for 29th

Annual

International Conference of the IEEE EMBS Lyon France

HighleyMan L Franciscus A (2011) Disease progression What is fibrosis

Hepatitis C Support Project Retrieved from

httpwwwhcvadvocateorghepatitisfactsheets_pdfFibrosispdf

Juergen

Braun Karl Braun and Ingolf

Sack Electromagnetic Actuator for

Generating Variably Oriented Shear Waves in MR Elastogrphy Magnetic

Resonance in Medicine 50220‐222(2003)

Kolipaka

A

Araoz

PA

McGee

KP Manduca

A

Ehman

RL (2010) Magnetic

resonance elastography

as a method for the assessment of effective myocardial

stiffness throughout the cardiac cycle

pubMed Retrieved from

httpwwwncbinlmnihgovpubmed20578052

McGee KP Lake D Mariappan

Y HubmayrRD Manduca

A Ansell K and Ehman

RL Calculation of shear

stiffness in noise dominated magnetic resonance elastography

data based on

principal frequency estimation 2011

Phys Med Biol

56

4291 34

Piezoelectric actuator

12

13

How to detect deformation

Phase‐contrast MRI‐

motion‐

sensitizing gradient

‐

Phase shift in received MR signal

14

Mechanical model

Mechanical properties of

tissue

‐first Lame constant(λ)

‐second Lame constant(μ)

‐bulk modulus K

= λ

+ (2 3)μ

‐Poissonrsquos ratio(v)

‐Youngrsquos modulus(E

15

Harmonic motion model

Helmholtzinversion

21 independent parameters

required

16

17

18

Applications Liver fibrosis

Causes hepatic diseases chronic Hepatitis C ALD

( alcoholic liver disease) fatty liver disease autoimmune

hepatitis

Response to injury scar formation But in fibrosis the

healing process goes wrong

Fibrosis is the accumulation of tough fibrous scar tissue in the

liver

Fibrosis

if left untreated leads to cirrhosis

Other imaging methods (CT MRI) are very limited in

detecting fibrosis before it has advanced to irreversible

cirrhosis

19

20

Using MRE

21

Patient A

normal liverMean shear

stiffness of

21kPa

Patient BHepatic

steatosis and

mild fibrosis 48 kPa

Patient CChronic liver

disease L most

areasgt 8kPa in

shear stiffness

22

MRE vs Biopsy

Highly accurate in detecting liver fibrosis

Much more efficient than a liver biopsy there

is a chance of underestimation of hepatic fibrosis by about 20 to 30‐

sampling error

94 to 97 accuracy

Most patients tend to delay taking a biopsy

since it is an invasive procedure

The earlier the hepatologist knows the

sooner the treatment can be given 23

Brain MR Elastography

Brain elasticity data can be used to detect certain diffuse diseases of the brain that are not well evaluated

by conventional imaging methods ‐Alzheimers‐Hydrocephalus‐focal brain lesions‐Multiple Sclerosis‐obtaining quantitative measurements of Elastic

modulus of cerebral tissue is of interest in biomechanical studies of brain trauma and in the

development of neurosurgery simulation techniques

24

MRE system designed for the brain

lsquoArsquo

applies vertical

displacement to the head

lsquoBrsquo

applies horizontal

displacement to the head

via a bite block

The θ

between the two can

be varied to image the

waves at various stages of

propagation

25

MRE system for a brain

Technical Challenges bullIntroducing s‐waves through the bony calvariumbullPerforming efficient sampling and processing of a 3D displacement field

Developed using a soft pillow like(passive) vibration (50 Hz) source to produce

intracranial s‐waves

26

Hydrocephalus

Obstruction of CSF flow in either

the lateral ventricles or the

subarachnoid space

Results in an increased size of

ventricles and therefore an

increase in intracranial pressure

(ICP)

MRI and CT assist in diagnosis

but they have limitations

These techniques only detect

ventricular enlargement which

can be confused with cerebral

atrophy or periventricular

leukomalacia (shrinkage of

periventricular white matter)

27

MRE diagnosis

Top normal patientBottom patient with hydrocephalus

28

MRE for detection of Cardiac disease states

HFPEF heart failure due to preserved ejection fraction

Hypertrophic cardiomyopathy

Load independent contractility

MI Myocardial infarction

29

Heart failure due to preserved Ejection fraction

30

HFpEf

Preserved ejection fraction

Efgt50

40 to 70 of heart failure

cases

Heart is contracting normally

but the ventricle walls are

stiff and do not relax

properly Less blood is

entering the heart during

systole

Patients with pEf also had

hypertension and coronary

artery diseases

31

Stiffness results

32

Future directions

Mechanical driver‐wave frequency‐multiple driver source

Data Processing

‐encoding process‐high‐speed 3D imaging‐new mathematical model for estimation of

tissue properties

33

References

Mauduca A Dynamic Magnetic Resonance Elastography Mayo Clinic College of

Medicine

Araoz

P Kolipaka

A mayo Clinic (Producer) (2010)Cardiac MRE [Web Video]

Retrieved from httpwwwyoutubecomwatchv=NyvjE5DpIis

Bachir T (2009)

Advanced MRI methods for assessment of chronic liver disease

Ehman R L (2009) Magnetic Resonance Elastography An emerging Tool for

Cellular Mechanobiology Mayo Clinic Rochester MN USA

Grenier

D Milot

L Peng

X Pilluel

F Beuf

O (2007) A Magnetic Resonance

Elastography

approach for liver investigationProceedings

for 29th

Annual

International Conference of the IEEE EMBS Lyon France

HighleyMan L Franciscus A (2011) Disease progression What is fibrosis

Hepatitis C Support Project Retrieved from

httpwwwhcvadvocateorghepatitisfactsheets_pdfFibrosispdf

Juergen

Braun Karl Braun and Ingolf

Sack Electromagnetic Actuator for

Generating Variably Oriented Shear Waves in MR Elastogrphy Magnetic

Resonance in Medicine 50220‐222(2003)

Kolipaka

A

Araoz

PA

McGee

KP Manduca

A

Ehman

RL (2010) Magnetic

resonance elastography

as a method for the assessment of effective myocardial

stiffness throughout the cardiac cycle

pubMed Retrieved from

httpwwwncbinlmnihgovpubmed20578052

McGee KP Lake D Mariappan

Y HubmayrRD Manduca

A Ansell K and Ehman

RL Calculation of shear

stiffness in noise dominated magnetic resonance elastography

data based on

principal frequency estimation 2011

Phys Med Biol

56

4291 34

13

How to detect deformation

Phase‐contrast MRI‐

motion‐

sensitizing gradient

‐

Phase shift in received MR signal

14

Mechanical model

Mechanical properties of

tissue

‐first Lame constant(λ)

‐second Lame constant(μ)

‐bulk modulus K

= λ

+ (2 3)μ

‐Poissonrsquos ratio(v)

‐Youngrsquos modulus(E

15

Harmonic motion model

Helmholtzinversion

21 independent parameters

required

16

17

18

Applications Liver fibrosis

Causes hepatic diseases chronic Hepatitis C ALD

( alcoholic liver disease) fatty liver disease autoimmune

hepatitis

Response to injury scar formation But in fibrosis the

healing process goes wrong

Fibrosis is the accumulation of tough fibrous scar tissue in the

liver

Fibrosis

if left untreated leads to cirrhosis

Other imaging methods (CT MRI) are very limited in

detecting fibrosis before it has advanced to irreversible

cirrhosis

19

20

Using MRE

21

Patient A

normal liverMean shear

stiffness of

21kPa

Patient BHepatic

steatosis and

mild fibrosis 48 kPa

Patient CChronic liver

disease L most

areasgt 8kPa in

shear stiffness

22

MRE vs Biopsy

Highly accurate in detecting liver fibrosis

Much more efficient than a liver biopsy there

is a chance of underestimation of hepatic fibrosis by about 20 to 30‐

sampling error

94 to 97 accuracy

Most patients tend to delay taking a biopsy

since it is an invasive procedure

The earlier the hepatologist knows the

sooner the treatment can be given 23

Brain MR Elastography

Brain elasticity data can be used to detect certain diffuse diseases of the brain that are not well evaluated

by conventional imaging methods ‐Alzheimers‐Hydrocephalus‐focal brain lesions‐Multiple Sclerosis‐obtaining quantitative measurements of Elastic

modulus of cerebral tissue is of interest in biomechanical studies of brain trauma and in the

development of neurosurgery simulation techniques

24

MRE system designed for the brain

lsquoArsquo

applies vertical

displacement to the head

lsquoBrsquo

applies horizontal

displacement to the head

via a bite block

The θ

between the two can

be varied to image the

waves at various stages of

propagation

25

MRE system for a brain

Technical Challenges bullIntroducing s‐waves through the bony calvariumbullPerforming efficient sampling and processing of a 3D displacement field

Developed using a soft pillow like(passive) vibration (50 Hz) source to produce

intracranial s‐waves

26

Hydrocephalus

Obstruction of CSF flow in either

the lateral ventricles or the

subarachnoid space

Results in an increased size of

ventricles and therefore an

increase in intracranial pressure

(ICP)

MRI and CT assist in diagnosis

but they have limitations

These techniques only detect

ventricular enlargement which

can be confused with cerebral

atrophy or periventricular

leukomalacia (shrinkage of

periventricular white matter)

27

MRE diagnosis

Top normal patientBottom patient with hydrocephalus

28

MRE for detection of Cardiac disease states

HFPEF heart failure due to preserved ejection fraction

Hypertrophic cardiomyopathy

Load independent contractility

MI Myocardial infarction

29

Heart failure due to preserved Ejection fraction

30

HFpEf

Preserved ejection fraction

Efgt50

40 to 70 of heart failure

cases

Heart is contracting normally

but the ventricle walls are

stiff and do not relax

properly Less blood is

entering the heart during

systole

Patients with pEf also had

hypertension and coronary

artery diseases

31

Stiffness results

32

Future directions

Mechanical driver‐wave frequency‐multiple driver source

Data Processing

‐encoding process‐high‐speed 3D imaging‐new mathematical model for estimation of

tissue properties

33

References

Mauduca A Dynamic Magnetic Resonance Elastography Mayo Clinic College of

Medicine

Araoz

P Kolipaka

A mayo Clinic (Producer) (2010)Cardiac MRE [Web Video]

Retrieved from httpwwwyoutubecomwatchv=NyvjE5DpIis

Bachir T (2009)

Advanced MRI methods for assessment of chronic liver disease

Ehman R L (2009) Magnetic Resonance Elastography An emerging Tool for

Cellular Mechanobiology Mayo Clinic Rochester MN USA

Grenier

D Milot

L Peng

X Pilluel

F Beuf

O (2007) A Magnetic Resonance

Elastography

approach for liver investigationProceedings

for 29th

Annual

International Conference of the IEEE EMBS Lyon France

HighleyMan L Franciscus A (2011) Disease progression What is fibrosis

Hepatitis C Support Project Retrieved from

httpwwwhcvadvocateorghepatitisfactsheets_pdfFibrosispdf

Juergen

Braun Karl Braun and Ingolf

Sack Electromagnetic Actuator for

Generating Variably Oriented Shear Waves in MR Elastogrphy Magnetic

Resonance in Medicine 50220‐222(2003)

Kolipaka

A

Araoz

PA

McGee

KP Manduca

A

Ehman

RL (2010) Magnetic

resonance elastography

as a method for the assessment of effective myocardial

stiffness throughout the cardiac cycle

pubMed Retrieved from

httpwwwncbinlmnihgovpubmed20578052

McGee KP Lake D Mariappan

Y HubmayrRD Manduca

A Ansell K and Ehman

RL Calculation of shear

stiffness in noise dominated magnetic resonance elastography

data based on

principal frequency estimation 2011

Phys Med Biol

56

4291 34

How to detect deformation

Phase‐contrast MRI‐

motion‐

sensitizing gradient

‐

Phase shift in received MR signal

14

Mechanical model

Mechanical properties of

tissue

‐first Lame constant(λ)

‐second Lame constant(μ)

‐bulk modulus K

= λ

+ (2 3)μ

‐Poissonrsquos ratio(v)

‐Youngrsquos modulus(E

15

Harmonic motion model

Helmholtzinversion

21 independent parameters

required

16

17

18

Applications Liver fibrosis

Causes hepatic diseases chronic Hepatitis C ALD

( alcoholic liver disease) fatty liver disease autoimmune

hepatitis

Response to injury scar formation But in fibrosis the

healing process goes wrong

Fibrosis is the accumulation of tough fibrous scar tissue in the

liver

Fibrosis

if left untreated leads to cirrhosis

Other imaging methods (CT MRI) are very limited in

detecting fibrosis before it has advanced to irreversible

cirrhosis

19

20

Using MRE

21

Patient A

normal liverMean shear

stiffness of

21kPa

Patient BHepatic

steatosis and

mild fibrosis 48 kPa

Patient CChronic liver

disease L most

areasgt 8kPa in

shear stiffness

22

MRE vs Biopsy

Highly accurate in detecting liver fibrosis

Much more efficient than a liver biopsy there

is a chance of underestimation of hepatic fibrosis by about 20 to 30‐

sampling error

94 to 97 accuracy

Most patients tend to delay taking a biopsy

since it is an invasive procedure

The earlier the hepatologist knows the

sooner the treatment can be given 23

Brain MR Elastography

Brain elasticity data can be used to detect certain diffuse diseases of the brain that are not well evaluated

by conventional imaging methods ‐Alzheimers‐Hydrocephalus‐focal brain lesions‐Multiple Sclerosis‐obtaining quantitative measurements of Elastic

modulus of cerebral tissue is of interest in biomechanical studies of brain trauma and in the

development of neurosurgery simulation techniques

24

MRE system designed for the brain

lsquoArsquo

applies vertical

displacement to the head

lsquoBrsquo

applies horizontal

displacement to the head

via a bite block

The θ

between the two can

be varied to image the

waves at various stages of

propagation

25

MRE system for a brain

Technical Challenges bullIntroducing s‐waves through the bony calvariumbullPerforming efficient sampling and processing of a 3D displacement field

Developed using a soft pillow like(passive) vibration (50 Hz) source to produce

intracranial s‐waves

26

Hydrocephalus

Obstruction of CSF flow in either

the lateral ventricles or the

subarachnoid space

Results in an increased size of

ventricles and therefore an

increase in intracranial pressure

(ICP)

MRI and CT assist in diagnosis

but they have limitations

These techniques only detect

ventricular enlargement which

can be confused with cerebral

atrophy or periventricular

leukomalacia (shrinkage of

periventricular white matter)

27

MRE diagnosis

Top normal patientBottom patient with hydrocephalus

28

MRE for detection of Cardiac disease states

HFPEF heart failure due to preserved ejection fraction

Hypertrophic cardiomyopathy

Load independent contractility

MI Myocardial infarction

29

Heart failure due to preserved Ejection fraction

30

HFpEf

Preserved ejection fraction

Efgt50

40 to 70 of heart failure

cases

Heart is contracting normally

but the ventricle walls are

stiff and do not relax

properly Less blood is

entering the heart during

systole

Patients with pEf also had

hypertension and coronary

artery diseases

31

Stiffness results

32

Future directions

Mechanical driver‐wave frequency‐multiple driver source

Data Processing

‐encoding process‐high‐speed 3D imaging‐new mathematical model for estimation of

tissue properties

33

References

Mauduca A Dynamic Magnetic Resonance Elastography Mayo Clinic College of

Medicine

Araoz

P Kolipaka

A mayo Clinic (Producer) (2010)Cardiac MRE [Web Video]

Retrieved from httpwwwyoutubecomwatchv=NyvjE5DpIis

Bachir T (2009)

Advanced MRI methods for assessment of chronic liver disease

Ehman R L (2009) Magnetic Resonance Elastography An emerging Tool for

Cellular Mechanobiology Mayo Clinic Rochester MN USA

Grenier

D Milot

L Peng

X Pilluel

F Beuf

O (2007) A Magnetic Resonance

Elastography

approach for liver investigationProceedings

for 29th

Annual

International Conference of the IEEE EMBS Lyon France

HighleyMan L Franciscus A (2011) Disease progression What is fibrosis

Hepatitis C Support Project Retrieved from

httpwwwhcvadvocateorghepatitisfactsheets_pdfFibrosispdf

Juergen

Braun Karl Braun and Ingolf

Sack Electromagnetic Actuator for

Generating Variably Oriented Shear Waves in MR Elastogrphy Magnetic

Resonance in Medicine 50220‐222(2003)

Kolipaka

A

Araoz

PA

McGee

KP Manduca

A

Ehman

RL (2010) Magnetic

resonance elastography

as a method for the assessment of effective myocardial

stiffness throughout the cardiac cycle

pubMed Retrieved from

httpwwwncbinlmnihgovpubmed20578052

McGee KP Lake D Mariappan

Y HubmayrRD Manduca

A Ansell K and Ehman

RL Calculation of shear

stiffness in noise dominated magnetic resonance elastography

data based on

principal frequency estimation 2011

Phys Med Biol

56

4291 34

Mechanical model

Mechanical properties of

tissue

‐first Lame constant(λ)

‐second Lame constant(μ)

‐bulk modulus K

= λ

+ (2 3)μ

‐Poissonrsquos ratio(v)

‐Youngrsquos modulus(E

15

Harmonic motion model

Helmholtzinversion

21 independent parameters

required

16

17

18

Applications Liver fibrosis

Causes hepatic diseases chronic Hepatitis C ALD

( alcoholic liver disease) fatty liver disease autoimmune

hepatitis

Response to injury scar formation But in fibrosis the

healing process goes wrong

Fibrosis is the accumulation of tough fibrous scar tissue in the

liver

Fibrosis

if left untreated leads to cirrhosis

Other imaging methods (CT MRI) are very limited in

detecting fibrosis before it has advanced to irreversible

cirrhosis

19

20

Using MRE

21

Patient A

normal liverMean shear

stiffness of

21kPa

Patient BHepatic

steatosis and

mild fibrosis 48 kPa

Patient CChronic liver

disease L most

areasgt 8kPa in

shear stiffness

22

MRE vs Biopsy

Highly accurate in detecting liver fibrosis

Much more efficient than a liver biopsy there

is a chance of underestimation of hepatic fibrosis by about 20 to 30‐

sampling error

94 to 97 accuracy

Most patients tend to delay taking a biopsy

since it is an invasive procedure

The earlier the hepatologist knows the

sooner the treatment can be given 23

Brain MR Elastography

Brain elasticity data can be used to detect certain diffuse diseases of the brain that are not well evaluated

by conventional imaging methods ‐Alzheimers‐Hydrocephalus‐focal brain lesions‐Multiple Sclerosis‐obtaining quantitative measurements of Elastic

modulus of cerebral tissue is of interest in biomechanical studies of brain trauma and in the

development of neurosurgery simulation techniques

24

MRE system designed for the brain

lsquoArsquo

applies vertical

displacement to the head

lsquoBrsquo

applies horizontal

displacement to the head

via a bite block

The θ

between the two can

be varied to image the

waves at various stages of

propagation

25

MRE system for a brain

Technical Challenges bullIntroducing s‐waves through the bony calvariumbullPerforming efficient sampling and processing of a 3D displacement field

Developed using a soft pillow like(passive) vibration (50 Hz) source to produce

intracranial s‐waves

26

Hydrocephalus

Obstruction of CSF flow in either

the lateral ventricles or the

subarachnoid space

Results in an increased size of

ventricles and therefore an

increase in intracranial pressure

(ICP)

MRI and CT assist in diagnosis

but they have limitations

These techniques only detect

ventricular enlargement which

can be confused with cerebral

atrophy or periventricular

leukomalacia (shrinkage of

periventricular white matter)

27

MRE diagnosis

Top normal patientBottom patient with hydrocephalus

28

MRE for detection of Cardiac disease states

HFPEF heart failure due to preserved ejection fraction

Hypertrophic cardiomyopathy

Load independent contractility

MI Myocardial infarction

29

Heart failure due to preserved Ejection fraction

30

HFpEf

Preserved ejection fraction

Efgt50

40 to 70 of heart failure

cases

Heart is contracting normally

but the ventricle walls are

stiff and do not relax

properly Less blood is

entering the heart during

systole

Patients with pEf also had

hypertension and coronary

artery diseases

31

Stiffness results

32

Future directions

Mechanical driver‐wave frequency‐multiple driver source

Data Processing

‐encoding process‐high‐speed 3D imaging‐new mathematical model for estimation of

tissue properties

33

References

Mauduca A Dynamic Magnetic Resonance Elastography Mayo Clinic College of

Medicine

Araoz

P Kolipaka

A mayo Clinic (Producer) (2010)Cardiac MRE [Web Video]

Retrieved from httpwwwyoutubecomwatchv=NyvjE5DpIis

Bachir T (2009)

Advanced MRI methods for assessment of chronic liver disease

Ehman R L (2009) Magnetic Resonance Elastography An emerging Tool for

Cellular Mechanobiology Mayo Clinic Rochester MN USA

Grenier

D Milot

L Peng

X Pilluel

F Beuf

O (2007) A Magnetic Resonance

Elastography

approach for liver investigationProceedings

for 29th

Annual

International Conference of the IEEE EMBS Lyon France

HighleyMan L Franciscus A (2011) Disease progression What is fibrosis

Hepatitis C Support Project Retrieved from

httpwwwhcvadvocateorghepatitisfactsheets_pdfFibrosispdf

Juergen

Braun Karl Braun and Ingolf

Sack Electromagnetic Actuator for

Generating Variably Oriented Shear Waves in MR Elastogrphy Magnetic

Resonance in Medicine 50220‐222(2003)

Kolipaka

A

Araoz

PA

McGee

KP Manduca

A

Ehman

RL (2010) Magnetic

resonance elastography

as a method for the assessment of effective myocardial

stiffness throughout the cardiac cycle

pubMed Retrieved from

httpwwwncbinlmnihgovpubmed20578052

McGee KP Lake D Mariappan

Y HubmayrRD Manduca

A Ansell K and Ehman

RL Calculation of shear

stiffness in noise dominated magnetic resonance elastography

data based on

principal frequency estimation 2011

Phys Med Biol

56

4291 34

Harmonic motion model

Helmholtzinversion

21 independent parameters

required

16

17

18

Applications Liver fibrosis

Causes hepatic diseases chronic Hepatitis C ALD

( alcoholic liver disease) fatty liver disease autoimmune

hepatitis

Response to injury scar formation But in fibrosis the

healing process goes wrong

Fibrosis is the accumulation of tough fibrous scar tissue in the

liver

Fibrosis

if left untreated leads to cirrhosis

Other imaging methods (CT MRI) are very limited in

detecting fibrosis before it has advanced to irreversible

cirrhosis

19

20

Using MRE

21

Patient A

normal liverMean shear

stiffness of

21kPa

Patient BHepatic

steatosis and

mild fibrosis 48 kPa

Patient CChronic liver

disease L most

areasgt 8kPa in

shear stiffness

22

MRE vs Biopsy

Highly accurate in detecting liver fibrosis

Much more efficient than a liver biopsy there

is a chance of underestimation of hepatic fibrosis by about 20 to 30‐

sampling error

94 to 97 accuracy

Most patients tend to delay taking a biopsy

since it is an invasive procedure

The earlier the hepatologist knows the

sooner the treatment can be given 23

Brain MR Elastography

Brain elasticity data can be used to detect certain diffuse diseases of the brain that are not well evaluated

by conventional imaging methods ‐Alzheimers‐Hydrocephalus‐focal brain lesions‐Multiple Sclerosis‐obtaining quantitative measurements of Elastic

modulus of cerebral tissue is of interest in biomechanical studies of brain trauma and in the

development of neurosurgery simulation techniques

24

MRE system designed for the brain

lsquoArsquo

applies vertical

displacement to the head

lsquoBrsquo

applies horizontal

displacement to the head

via a bite block

The θ

between the two can

be varied to image the

waves at various stages of

propagation

25

MRE system for a brain

Technical Challenges bullIntroducing s‐waves through the bony calvariumbullPerforming efficient sampling and processing of a 3D displacement field

Developed using a soft pillow like(passive) vibration (50 Hz) source to produce

intracranial s‐waves

26

Hydrocephalus

Obstruction of CSF flow in either

the lateral ventricles or the

subarachnoid space

Results in an increased size of

ventricles and therefore an

increase in intracranial pressure

(ICP)

MRI and CT assist in diagnosis

but they have limitations

These techniques only detect

ventricular enlargement which

can be confused with cerebral

atrophy or periventricular

leukomalacia (shrinkage of

periventricular white matter)

27

MRE diagnosis

Top normal patientBottom patient with hydrocephalus

28

MRE for detection of Cardiac disease states

HFPEF heart failure due to preserved ejection fraction

Hypertrophic cardiomyopathy

Load independent contractility

MI Myocardial infarction

29

Heart failure due to preserved Ejection fraction

30

HFpEf

Preserved ejection fraction

Efgt50

40 to 70 of heart failure

cases

Heart is contracting normally

but the ventricle walls are

stiff and do not relax

properly Less blood is

entering the heart during

systole

Patients with pEf also had

hypertension and coronary

artery diseases

31

Stiffness results

32

Future directions

Mechanical driver‐wave frequency‐multiple driver source

Data Processing

‐encoding process‐high‐speed 3D imaging‐new mathematical model for estimation of

tissue properties

33

References

Mauduca A Dynamic Magnetic Resonance Elastography Mayo Clinic College of

Medicine

Araoz

P Kolipaka

A mayo Clinic (Producer) (2010)Cardiac MRE [Web Video]

Retrieved from httpwwwyoutubecomwatchv=NyvjE5DpIis

Bachir T (2009)

Advanced MRI methods for assessment of chronic liver disease

Ehman R L (2009) Magnetic Resonance Elastography An emerging Tool for

Cellular Mechanobiology Mayo Clinic Rochester MN USA

Grenier

D Milot

L Peng

X Pilluel

F Beuf

O (2007) A Magnetic Resonance

Elastography

approach for liver investigationProceedings

for 29th

Annual

International Conference of the IEEE EMBS Lyon France

HighleyMan L Franciscus A (2011) Disease progression What is fibrosis

Hepatitis C Support Project Retrieved from

httpwwwhcvadvocateorghepatitisfactsheets_pdfFibrosispdf

Juergen

Braun Karl Braun and Ingolf

Sack Electromagnetic Actuator for

Generating Variably Oriented Shear Waves in MR Elastogrphy Magnetic

Resonance in Medicine 50220‐222(2003)

Kolipaka

A

Araoz

PA

McGee

KP Manduca

A

Ehman

RL (2010) Magnetic

resonance elastography

as a method for the assessment of effective myocardial

stiffness throughout the cardiac cycle

pubMed Retrieved from

httpwwwncbinlmnihgovpubmed20578052

McGee KP Lake D Mariappan

Y HubmayrRD Manduca

A Ansell K and Ehman

RL Calculation of shear

stiffness in noise dominated magnetic resonance elastography

data based on

principal frequency estimation 2011

Phys Med Biol

56

4291 34

17

18

Applications Liver fibrosis

Causes hepatic diseases chronic Hepatitis C ALD

( alcoholic liver disease) fatty liver disease autoimmune

hepatitis

Response to injury scar formation But in fibrosis the

healing process goes wrong

Fibrosis is the accumulation of tough fibrous scar tissue in the

liver

Fibrosis

if left untreated leads to cirrhosis

Other imaging methods (CT MRI) are very limited in

detecting fibrosis before it has advanced to irreversible

cirrhosis

19

20

Using MRE

21

Patient A

normal liverMean shear

stiffness of

21kPa

Patient BHepatic

steatosis and

mild fibrosis 48 kPa

Patient CChronic liver

disease L most

areasgt 8kPa in

shear stiffness

22

MRE vs Biopsy

Highly accurate in detecting liver fibrosis

Much more efficient than a liver biopsy there

is a chance of underestimation of hepatic fibrosis by about 20 to 30‐

sampling error

94 to 97 accuracy

Most patients tend to delay taking a biopsy

since it is an invasive procedure

The earlier the hepatologist knows the

sooner the treatment can be given 23

Brain MR Elastography

Brain elasticity data can be used to detect certain diffuse diseases of the brain that are not well evaluated

by conventional imaging methods ‐Alzheimers‐Hydrocephalus‐focal brain lesions‐Multiple Sclerosis‐obtaining quantitative measurements of Elastic

modulus of cerebral tissue is of interest in biomechanical studies of brain trauma and in the

development of neurosurgery simulation techniques

24

MRE system designed for the brain

lsquoArsquo

applies vertical

displacement to the head

lsquoBrsquo

applies horizontal

displacement to the head

via a bite block

The θ

between the two can

be varied to image the

waves at various stages of

propagation

25

MRE system for a brain

Technical Challenges bullIntroducing s‐waves through the bony calvariumbullPerforming efficient sampling and processing of a 3D displacement field

Developed using a soft pillow like(passive) vibration (50 Hz) source to produce

intracranial s‐waves

26

Hydrocephalus

Obstruction of CSF flow in either

the lateral ventricles or the

subarachnoid space

Results in an increased size of

ventricles and therefore an

increase in intracranial pressure

(ICP)

MRI and CT assist in diagnosis

but they have limitations

These techniques only detect

ventricular enlargement which

can be confused with cerebral

atrophy or periventricular

leukomalacia (shrinkage of

periventricular white matter)

27

MRE diagnosis

Top normal patientBottom patient with hydrocephalus

28

MRE for detection of Cardiac disease states

HFPEF heart failure due to preserved ejection fraction

Hypertrophic cardiomyopathy

Load independent contractility

MI Myocardial infarction

29

Heart failure due to preserved Ejection fraction

30

HFpEf

Preserved ejection fraction

Efgt50

40 to 70 of heart failure

cases

Heart is contracting normally

but the ventricle walls are

stiff and do not relax

properly Less blood is

entering the heart during

systole

Patients with pEf also had

hypertension and coronary

artery diseases

31

Stiffness results

32

Future directions

Mechanical driver‐wave frequency‐multiple driver source

Data Processing

‐encoding process‐high‐speed 3D imaging‐new mathematical model for estimation of

tissue properties

33

References

Mauduca A Dynamic Magnetic Resonance Elastography Mayo Clinic College of

Medicine

Araoz

P Kolipaka

A mayo Clinic (Producer) (2010)Cardiac MRE [Web Video]

Retrieved from httpwwwyoutubecomwatchv=NyvjE5DpIis

Bachir T (2009)

Advanced MRI methods for assessment of chronic liver disease

Ehman R L (2009) Magnetic Resonance Elastography An emerging Tool for

Cellular Mechanobiology Mayo Clinic Rochester MN USA

Grenier

D Milot

L Peng

X Pilluel

F Beuf

O (2007) A Magnetic Resonance

Elastography

approach for liver investigationProceedings

for 29th

Annual

International Conference of the IEEE EMBS Lyon France

HighleyMan L Franciscus A (2011) Disease progression What is fibrosis

Hepatitis C Support Project Retrieved from

httpwwwhcvadvocateorghepatitisfactsheets_pdfFibrosispdf

Juergen

Braun Karl Braun and Ingolf

Sack Electromagnetic Actuator for

Generating Variably Oriented Shear Waves in MR Elastogrphy Magnetic

Resonance in Medicine 50220‐222(2003)

Kolipaka

A

Araoz

PA

McGee

KP Manduca

A

Ehman

RL (2010) Magnetic

resonance elastography

as a method for the assessment of effective myocardial

stiffness throughout the cardiac cycle

pubMed Retrieved from

httpwwwncbinlmnihgovpubmed20578052

McGee KP Lake D Mariappan

Y HubmayrRD Manduca

A Ansell K and Ehman

RL Calculation of shear

stiffness in noise dominated magnetic resonance elastography

data based on

principal frequency estimation 2011

Phys Med Biol

56

4291 34

18

Applications Liver fibrosis

Causes hepatic diseases chronic Hepatitis C ALD

( alcoholic liver disease) fatty liver disease autoimmune

hepatitis

Response to injury scar formation But in fibrosis the

healing process goes wrong

Fibrosis is the accumulation of tough fibrous scar tissue in the

liver

Fibrosis

if left untreated leads to cirrhosis

Other imaging methods (CT MRI) are very limited in

detecting fibrosis before it has advanced to irreversible

cirrhosis

19

20

Using MRE

21

Patient A

normal liverMean shear

stiffness of

21kPa

Patient BHepatic

steatosis and

mild fibrosis 48 kPa

Patient CChronic liver

disease L most

areasgt 8kPa in

shear stiffness

22

MRE vs Biopsy

Highly accurate in detecting liver fibrosis

Much more efficient than a liver biopsy there

is a chance of underestimation of hepatic fibrosis by about 20 to 30‐

sampling error

94 to 97 accuracy

Most patients tend to delay taking a biopsy

since it is an invasive procedure

The earlier the hepatologist knows the

sooner the treatment can be given 23

Brain MR Elastography

Brain elasticity data can be used to detect certain diffuse diseases of the brain that are not well evaluated

by conventional imaging methods ‐Alzheimers‐Hydrocephalus‐focal brain lesions‐Multiple Sclerosis‐obtaining quantitative measurements of Elastic

modulus of cerebral tissue is of interest in biomechanical studies of brain trauma and in the

development of neurosurgery simulation techniques

24

MRE system designed for the brain

lsquoArsquo

applies vertical

displacement to the head

lsquoBrsquo

applies horizontal

displacement to the head

via a bite block

The θ

between the two can

be varied to image the

waves at various stages of

propagation

25

MRE system for a brain

Technical Challenges bullIntroducing s‐waves through the bony calvariumbullPerforming efficient sampling and processing of a 3D displacement field

Developed using a soft pillow like(passive) vibration (50 Hz) source to produce

intracranial s‐waves

26

Hydrocephalus

Obstruction of CSF flow in either

the lateral ventricles or the

subarachnoid space

Results in an increased size of

ventricles and therefore an

increase in intracranial pressure

(ICP)

MRI and CT assist in diagnosis

but they have limitations

These techniques only detect

ventricular enlargement which

can be confused with cerebral

atrophy or periventricular

leukomalacia (shrinkage of

periventricular white matter)

27

MRE diagnosis

Top normal patientBottom patient with hydrocephalus

28

MRE for detection of Cardiac disease states

HFPEF heart failure due to preserved ejection fraction

Hypertrophic cardiomyopathy

Load independent contractility

MI Myocardial infarction

29

Heart failure due to preserved Ejection fraction

30

HFpEf

Preserved ejection fraction

Efgt50

40 to 70 of heart failure

cases

Heart is contracting normally

but the ventricle walls are

stiff and do not relax

properly Less blood is

entering the heart during

systole

Patients with pEf also had

hypertension and coronary

artery diseases

31

Stiffness results

32

Future directions

Mechanical driver‐wave frequency‐multiple driver source

Data Processing

‐encoding process‐high‐speed 3D imaging‐new mathematical model for estimation of

tissue properties

33

References

Mauduca A Dynamic Magnetic Resonance Elastography Mayo Clinic College of

Medicine

Araoz

P Kolipaka

A mayo Clinic (Producer) (2010)Cardiac MRE [Web Video]

Retrieved from httpwwwyoutubecomwatchv=NyvjE5DpIis

Bachir T (2009)

Advanced MRI methods for assessment of chronic liver disease

Ehman R L (2009) Magnetic Resonance Elastography An emerging Tool for

Cellular Mechanobiology Mayo Clinic Rochester MN USA

Grenier

D Milot

L Peng

X Pilluel

F Beuf

O (2007) A Magnetic Resonance

Elastography

approach for liver investigationProceedings

for 29th

Annual

International Conference of the IEEE EMBS Lyon France

HighleyMan L Franciscus A (2011) Disease progression What is fibrosis

Hepatitis C Support Project Retrieved from

httpwwwhcvadvocateorghepatitisfactsheets_pdfFibrosispdf

Juergen

Braun Karl Braun and Ingolf

Sack Electromagnetic Actuator for

Generating Variably Oriented Shear Waves in MR Elastogrphy Magnetic

Resonance in Medicine 50220‐222(2003)

Kolipaka

A

Araoz

PA

McGee

KP Manduca

A

Ehman

RL (2010) Magnetic

resonance elastography

as a method for the assessment of effective myocardial

stiffness throughout the cardiac cycle

pubMed Retrieved from

httpwwwncbinlmnihgovpubmed20578052

McGee KP Lake D Mariappan

Y HubmayrRD Manduca

A Ansell K and Ehman

RL Calculation of shear

stiffness in noise dominated magnetic resonance elastography

data based on

principal frequency estimation 2011

Phys Med Biol

56

4291 34

Applications Liver fibrosis

Causes hepatic diseases chronic Hepatitis C ALD

( alcoholic liver disease) fatty liver disease autoimmune

hepatitis

Response to injury scar formation But in fibrosis the

healing process goes wrong

Fibrosis is the accumulation of tough fibrous scar tissue in the

liver

Fibrosis

if left untreated leads to cirrhosis

Other imaging methods (CT MRI) are very limited in

detecting fibrosis before it has advanced to irreversible

cirrhosis

19

20

Using MRE

21

Patient A

normal liverMean shear

stiffness of

21kPa

Patient BHepatic

steatosis and

mild fibrosis 48 kPa

Patient CChronic liver

disease L most

areasgt 8kPa in

shear stiffness

22

MRE vs Biopsy

Highly accurate in detecting liver fibrosis

Much more efficient than a liver biopsy there

is a chance of underestimation of hepatic fibrosis by about 20 to 30‐

sampling error

94 to 97 accuracy

Most patients tend to delay taking a biopsy

since it is an invasive procedure

The earlier the hepatologist knows the

sooner the treatment can be given 23

Brain MR Elastography

Brain elasticity data can be used to detect certain diffuse diseases of the brain that are not well evaluated

by conventional imaging methods ‐Alzheimers‐Hydrocephalus‐focal brain lesions‐Multiple Sclerosis‐obtaining quantitative measurements of Elastic

modulus of cerebral tissue is of interest in biomechanical studies of brain trauma and in the

development of neurosurgery simulation techniques

24

MRE system designed for the brain

lsquoArsquo

applies vertical

displacement to the head

lsquoBrsquo

applies horizontal

displacement to the head

via a bite block

The θ

between the two can

be varied to image the

waves at various stages of

propagation

25

MRE system for a brain

Technical Challenges bullIntroducing s‐waves through the bony calvariumbullPerforming efficient sampling and processing of a 3D displacement field

Developed using a soft pillow like(passive) vibration (50 Hz) source to produce

intracranial s‐waves

26

Hydrocephalus

Obstruction of CSF flow in either

the lateral ventricles or the

subarachnoid space

Results in an increased size of

ventricles and therefore an

increase in intracranial pressure

(ICP)

MRI and CT assist in diagnosis

but they have limitations

These techniques only detect

ventricular enlargement which

can be confused with cerebral

atrophy or periventricular

leukomalacia (shrinkage of

periventricular white matter)

27

MRE diagnosis

Top normal patientBottom patient with hydrocephalus

28

MRE for detection of Cardiac disease states

HFPEF heart failure due to preserved ejection fraction

Hypertrophic cardiomyopathy

Load independent contractility

MI Myocardial infarction

29

Heart failure due to preserved Ejection fraction

30

HFpEf

Preserved ejection fraction

Efgt50

40 to 70 of heart failure

cases

Heart is contracting normally

but the ventricle walls are

stiff and do not relax

properly Less blood is

entering the heart during

systole

Patients with pEf also had

hypertension and coronary

artery diseases

31

Stiffness results

32

Future directions

Mechanical driver‐wave frequency‐multiple driver source

Data Processing

‐encoding process‐high‐speed 3D imaging‐new mathematical model for estimation of

tissue properties

33

References

Mauduca A Dynamic Magnetic Resonance Elastography Mayo Clinic College of

Medicine

Araoz

P Kolipaka

A mayo Clinic (Producer) (2010)Cardiac MRE [Web Video]

Retrieved from httpwwwyoutubecomwatchv=NyvjE5DpIis

Bachir T (2009)

Advanced MRI methods for assessment of chronic liver disease

Ehman R L (2009) Magnetic Resonance Elastography An emerging Tool for

Cellular Mechanobiology Mayo Clinic Rochester MN USA

Grenier

D Milot

L Peng

X Pilluel

F Beuf

O (2007) A Magnetic Resonance

Elastography

approach for liver investigationProceedings

for 29th

Annual

International Conference of the IEEE EMBS Lyon France

HighleyMan L Franciscus A (2011) Disease progression What is fibrosis

Hepatitis C Support Project Retrieved from

httpwwwhcvadvocateorghepatitisfactsheets_pdfFibrosispdf

Juergen

Braun Karl Braun and Ingolf

Sack Electromagnetic Actuator for

Generating Variably Oriented Shear Waves in MR Elastogrphy Magnetic

Resonance in Medicine 50220‐222(2003)

Kolipaka

A

Araoz

PA

McGee

KP Manduca

A

Ehman

RL (2010) Magnetic

resonance elastography

as a method for the assessment of effective myocardial

stiffness throughout the cardiac cycle

pubMed Retrieved from

httpwwwncbinlmnihgovpubmed20578052

McGee KP Lake D Mariappan

Y HubmayrRD Manduca

A Ansell K and Ehman

RL Calculation of shear

stiffness in noise dominated magnetic resonance elastography

data based on

principal frequency estimation 2011

Phys Med Biol

56

4291 34

20

Using MRE

21

Patient A

normal liverMean shear

stiffness of

21kPa

Patient BHepatic

steatosis and

mild fibrosis 48 kPa

Patient CChronic liver

disease L most

areasgt 8kPa in

shear stiffness

22

MRE vs Biopsy

Highly accurate in detecting liver fibrosis

Much more efficient than a liver biopsy there

is a chance of underestimation of hepatic fibrosis by about 20 to 30‐

sampling error

94 to 97 accuracy

Most patients tend to delay taking a biopsy

since it is an invasive procedure

The earlier the hepatologist knows the

sooner the treatment can be given 23

Brain MR Elastography

Brain elasticity data can be used to detect certain diffuse diseases of the brain that are not well evaluated

by conventional imaging methods ‐Alzheimers‐Hydrocephalus‐focal brain lesions‐Multiple Sclerosis‐obtaining quantitative measurements of Elastic

modulus of cerebral tissue is of interest in biomechanical studies of brain trauma and in the

development of neurosurgery simulation techniques

24

MRE system designed for the brain

lsquoArsquo

applies vertical

displacement to the head

lsquoBrsquo

applies horizontal

displacement to the head

via a bite block

The θ

between the two can

be varied to image the

waves at various stages of

propagation

25

MRE system for a brain

Technical Challenges bullIntroducing s‐waves through the bony calvariumbullPerforming efficient sampling and processing of a 3D displacement field

Developed using a soft pillow like(passive) vibration (50 Hz) source to produce

intracranial s‐waves

26

Hydrocephalus

Obstruction of CSF flow in either

the lateral ventricles or the

subarachnoid space

Results in an increased size of

ventricles and therefore an

increase in intracranial pressure

(ICP)

MRI and CT assist in diagnosis

but they have limitations

These techniques only detect

ventricular enlargement which

can be confused with cerebral

atrophy or periventricular

leukomalacia (shrinkage of

periventricular white matter)

27

MRE diagnosis

Top normal patientBottom patient with hydrocephalus

28

MRE for detection of Cardiac disease states

HFPEF heart failure due to preserved ejection fraction

Hypertrophic cardiomyopathy

Load independent contractility

MI Myocardial infarction

29

Heart failure due to preserved Ejection fraction

30

HFpEf

Preserved ejection fraction

Efgt50

40 to 70 of heart failure

cases

Heart is contracting normally

but the ventricle walls are

stiff and do not relax

properly Less blood is

entering the heart during

systole

Patients with pEf also had

hypertension and coronary

artery diseases

31

Stiffness results

32

Future directions

Mechanical driver‐wave frequency‐multiple driver source

Data Processing

‐encoding process‐high‐speed 3D imaging‐new mathematical model for estimation of

tissue properties

33

References

Mauduca A Dynamic Magnetic Resonance Elastography Mayo Clinic College of

Medicine

Araoz

P Kolipaka

A mayo Clinic (Producer) (2010)Cardiac MRE [Web Video]

Retrieved from httpwwwyoutubecomwatchv=NyvjE5DpIis

Bachir T (2009)

Advanced MRI methods for assessment of chronic liver disease

Ehman R L (2009) Magnetic Resonance Elastography An emerging Tool for

Cellular Mechanobiology Mayo Clinic Rochester MN USA

Grenier

D Milot

L Peng

X Pilluel

F Beuf

O (2007) A Magnetic Resonance

Elastography

approach for liver investigationProceedings

for 29th

Annual

International Conference of the IEEE EMBS Lyon France

HighleyMan L Franciscus A (2011) Disease progression What is fibrosis

Hepatitis C Support Project Retrieved from

httpwwwhcvadvocateorghepatitisfactsheets_pdfFibrosispdf

Juergen

Braun Karl Braun and Ingolf

Sack Electromagnetic Actuator for

Generating Variably Oriented Shear Waves in MR Elastogrphy Magnetic

Resonance in Medicine 50220‐222(2003)

Kolipaka

A

Araoz

PA

McGee

KP Manduca

A

Ehman

RL (2010) Magnetic

resonance elastography

as a method for the assessment of effective myocardial

stiffness throughout the cardiac cycle

pubMed Retrieved from

httpwwwncbinlmnihgovpubmed20578052

McGee KP Lake D Mariappan

Y HubmayrRD Manduca

A Ansell K and Ehman

RL Calculation of shear

stiffness in noise dominated magnetic resonance elastography

data based on

principal frequency estimation 2011

Phys Med Biol

56

4291 34

Using MRE

21

Patient A

normal liverMean shear

stiffness of

21kPa

Patient BHepatic

steatosis and

mild fibrosis 48 kPa

Patient CChronic liver

disease L most

areasgt 8kPa in

shear stiffness

22

MRE vs Biopsy

Highly accurate in detecting liver fibrosis

Much more efficient than a liver biopsy there

is a chance of underestimation of hepatic fibrosis by about 20 to 30‐

sampling error

94 to 97 accuracy

Most patients tend to delay taking a biopsy

since it is an invasive procedure

The earlier the hepatologist knows the

sooner the treatment can be given 23

Brain MR Elastography

Brain elasticity data can be used to detect certain diffuse diseases of the brain that are not well evaluated

by conventional imaging methods ‐Alzheimers‐Hydrocephalus‐focal brain lesions‐Multiple Sclerosis‐obtaining quantitative measurements of Elastic

modulus of cerebral tissue is of interest in biomechanical studies of brain trauma and in the

development of neurosurgery simulation techniques

24

MRE system designed for the brain

lsquoArsquo

applies vertical

displacement to the head

lsquoBrsquo

applies horizontal

displacement to the head

via a bite block

The θ

between the two can

be varied to image the

waves at various stages of

propagation

25

MRE system for a brain

Technical Challenges bullIntroducing s‐waves through the bony calvariumbullPerforming efficient sampling and processing of a 3D displacement field

Developed using a soft pillow like(passive) vibration (50 Hz) source to produce

intracranial s‐waves

26

Hydrocephalus

Obstruction of CSF flow in either

the lateral ventricles or the

subarachnoid space

Results in an increased size of

ventricles and therefore an

increase in intracranial pressure

(ICP)

MRI and CT assist in diagnosis

but they have limitations

These techniques only detect

ventricular enlargement which

can be confused with cerebral

atrophy or periventricular

leukomalacia (shrinkage of

periventricular white matter)

27

MRE diagnosis

Top normal patientBottom patient with hydrocephalus

28

MRE for detection of Cardiac disease states

HFPEF heart failure due to preserved ejection fraction

Hypertrophic cardiomyopathy

Load independent contractility

MI Myocardial infarction

29

Heart failure due to preserved Ejection fraction

30

HFpEf

Preserved ejection fraction

Efgt50

40 to 70 of heart failure

cases

Heart is contracting normally

but the ventricle walls are

stiff and do not relax

properly Less blood is

entering the heart during

systole

Patients with pEf also had

hypertension and coronary

artery diseases

31

Stiffness results

32

Future directions

Mechanical driver‐wave frequency‐multiple driver source

Data Processing

‐encoding process‐high‐speed 3D imaging‐new mathematical model for estimation of

tissue properties

33

References

Mauduca A Dynamic Magnetic Resonance Elastography Mayo Clinic College of

Medicine

Araoz

P Kolipaka

A mayo Clinic (Producer) (2010)Cardiac MRE [Web Video]

Retrieved from httpwwwyoutubecomwatchv=NyvjE5DpIis

Bachir T (2009)

Advanced MRI methods for assessment of chronic liver disease

Ehman R L (2009) Magnetic Resonance Elastography An emerging Tool for

Cellular Mechanobiology Mayo Clinic Rochester MN USA

Grenier

D Milot

L Peng

X Pilluel

F Beuf

O (2007) A Magnetic Resonance

Elastography

approach for liver investigationProceedings

for 29th

Annual

International Conference of the IEEE EMBS Lyon France

HighleyMan L Franciscus A (2011) Disease progression What is fibrosis

Hepatitis C Support Project Retrieved from

httpwwwhcvadvocateorghepatitisfactsheets_pdfFibrosispdf

Juergen

Braun Karl Braun and Ingolf

Sack Electromagnetic Actuator for

Generating Variably Oriented Shear Waves in MR Elastogrphy Magnetic

Resonance in Medicine 50220‐222(2003)

Kolipaka

A

Araoz

PA

McGee

KP Manduca

A

Ehman

RL (2010) Magnetic

resonance elastography

as a method for the assessment of effective myocardial

stiffness throughout the cardiac cycle

pubMed Retrieved from

httpwwwncbinlmnihgovpubmed20578052

McGee KP Lake D Mariappan

Y HubmayrRD Manduca

A Ansell K and Ehman

RL Calculation of shear

stiffness in noise dominated magnetic resonance elastography

data based on

principal frequency estimation 2011

Phys Med Biol

56

4291 34

Patient A

normal liverMean shear

stiffness of

21kPa

Patient BHepatic

steatosis and

mild fibrosis 48 kPa

Patient CChronic liver

disease L most

areasgt 8kPa in

shear stiffness

22

MRE vs Biopsy

Highly accurate in detecting liver fibrosis

Much more efficient than a liver biopsy there

is a chance of underestimation of hepatic fibrosis by about 20 to 30‐

sampling error

94 to 97 accuracy

Most patients tend to delay taking a biopsy

since it is an invasive procedure

The earlier the hepatologist knows the

sooner the treatment can be given 23

Brain MR Elastography

Brain elasticity data can be used to detect certain diffuse diseases of the brain that are not well evaluated

by conventional imaging methods ‐Alzheimers‐Hydrocephalus‐focal brain lesions‐Multiple Sclerosis‐obtaining quantitative measurements of Elastic

modulus of cerebral tissue is of interest in biomechanical studies of brain trauma and in the

development of neurosurgery simulation techniques

24

MRE system designed for the brain

lsquoArsquo

applies vertical

displacement to the head

lsquoBrsquo

applies horizontal

displacement to the head

via a bite block

The θ

between the two can

be varied to image the

waves at various stages of

propagation

25

MRE system for a brain

Technical Challenges bullIntroducing s‐waves through the bony calvariumbullPerforming efficient sampling and processing of a 3D displacement field

Developed using a soft pillow like(passive) vibration (50 Hz) source to produce

intracranial s‐waves

26

Hydrocephalus

Obstruction of CSF flow in either

the lateral ventricles or the

subarachnoid space

Results in an increased size of

ventricles and therefore an

increase in intracranial pressure

(ICP)

MRI and CT assist in diagnosis

but they have limitations

These techniques only detect

ventricular enlargement which

can be confused with cerebral

atrophy or periventricular

leukomalacia (shrinkage of

periventricular white matter)

27

MRE diagnosis

Top normal patientBottom patient with hydrocephalus

28

MRE for detection of Cardiac disease states

HFPEF heart failure due to preserved ejection fraction

Hypertrophic cardiomyopathy

Load independent contractility

MI Myocardial infarction

29

Heart failure due to preserved Ejection fraction

30

HFpEf

Preserved ejection fraction

Efgt50

40 to 70 of heart failure

cases

Heart is contracting normally

but the ventricle walls are

stiff and do not relax

properly Less blood is

entering the heart during

systole

Patients with pEf also had

hypertension and coronary

artery diseases

31

Stiffness results

32

Future directions

Mechanical driver‐wave frequency‐multiple driver source

Data Processing

‐encoding process‐high‐speed 3D imaging‐new mathematical model for estimation of

tissue properties

33

References

Mauduca A Dynamic Magnetic Resonance Elastography Mayo Clinic College of

Medicine

Araoz

P Kolipaka

A mayo Clinic (Producer) (2010)Cardiac MRE [Web Video]

Retrieved from httpwwwyoutubecomwatchv=NyvjE5DpIis

Bachir T (2009)

Advanced MRI methods for assessment of chronic liver disease

Ehman R L (2009) Magnetic Resonance Elastography An emerging Tool for

Cellular Mechanobiology Mayo Clinic Rochester MN USA

Grenier

D Milot

L Peng

X Pilluel

F Beuf

O (2007) A Magnetic Resonance

Elastography

approach for liver investigationProceedings

for 29th

Annual

International Conference of the IEEE EMBS Lyon France

HighleyMan L Franciscus A (2011) Disease progression What is fibrosis

Hepatitis C Support Project Retrieved from

httpwwwhcvadvocateorghepatitisfactsheets_pdfFibrosispdf

Juergen

Braun Karl Braun and Ingolf

Sack Electromagnetic Actuator for

Generating Variably Oriented Shear Waves in MR Elastogrphy Magnetic

Resonance in Medicine 50220‐222(2003)

Kolipaka

A

Araoz

PA

McGee

KP Manduca

A

Ehman

RL (2010) Magnetic

resonance elastography

as a method for the assessment of effective myocardial

stiffness throughout the cardiac cycle

pubMed Retrieved from

httpwwwncbinlmnihgovpubmed20578052

McGee KP Lake D Mariappan

Y HubmayrRD Manduca

A Ansell K and Ehman

RL Calculation of shear

stiffness in noise dominated magnetic resonance elastography

data based on

principal frequency estimation 2011

Phys Med Biol

56

4291 34

MRE vs Biopsy

Highly accurate in detecting liver fibrosis

Much more efficient than a liver biopsy there

is a chance of underestimation of hepatic fibrosis by about 20 to 30‐

sampling error

94 to 97 accuracy

Most patients tend to delay taking a biopsy

since it is an invasive procedure

The earlier the hepatologist knows the

sooner the treatment can be given 23

Brain MR Elastography

Brain elasticity data can be used to detect certain diffuse diseases of the brain that are not well evaluated

by conventional imaging methods ‐Alzheimers‐Hydrocephalus‐focal brain lesions‐Multiple Sclerosis‐obtaining quantitative measurements of Elastic

modulus of cerebral tissue is of interest in biomechanical studies of brain trauma and in the

development of neurosurgery simulation techniques

24

MRE system designed for the brain

lsquoArsquo

applies vertical

displacement to the head

lsquoBrsquo

applies horizontal

displacement to the head

via a bite block

The θ

between the two can

be varied to image the

waves at various stages of

propagation

25

MRE system for a brain

Technical Challenges bullIntroducing s‐waves through the bony calvariumbullPerforming efficient sampling and processing of a 3D displacement field

Developed using a soft pillow like(passive) vibration (50 Hz) source to produce

intracranial s‐waves

26

Hydrocephalus

Obstruction of CSF flow in either

the lateral ventricles or the

subarachnoid space

Results in an increased size of

ventricles and therefore an

increase in intracranial pressure

(ICP)

MRI and CT assist in diagnosis

but they have limitations

These techniques only detect

ventricular enlargement which

can be confused with cerebral

atrophy or periventricular

leukomalacia (shrinkage of

periventricular white matter)

27

MRE diagnosis

Top normal patientBottom patient with hydrocephalus

28

MRE for detection of Cardiac disease states

HFPEF heart failure due to preserved ejection fraction

Hypertrophic cardiomyopathy

Load independent contractility

MI Myocardial infarction

29

Heart failure due to preserved Ejection fraction

30

HFpEf

Preserved ejection fraction

Efgt50

40 to 70 of heart failure

cases

Heart is contracting normally

but the ventricle walls are

stiff and do not relax

properly Less blood is

entering the heart during

systole

Patients with pEf also had

hypertension and coronary

artery diseases

31

Stiffness results

32

Future directions

Mechanical driver‐wave frequency‐multiple driver source

Data Processing

‐encoding process‐high‐speed 3D imaging‐new mathematical model for estimation of

tissue properties

33

References

Mauduca A Dynamic Magnetic Resonance Elastography Mayo Clinic College of

Medicine

Araoz

P Kolipaka

A mayo Clinic (Producer) (2010)Cardiac MRE [Web Video]

Retrieved from httpwwwyoutubecomwatchv=NyvjE5DpIis

Bachir T (2009)

Advanced MRI methods for assessment of chronic liver disease

Ehman R L (2009) Magnetic Resonance Elastography An emerging Tool for

Cellular Mechanobiology Mayo Clinic Rochester MN USA

Grenier

D Milot

L Peng

X Pilluel

F Beuf

O (2007) A Magnetic Resonance

Elastography

approach for liver investigationProceedings

for 29th

Annual

International Conference of the IEEE EMBS Lyon France

HighleyMan L Franciscus A (2011) Disease progression What is fibrosis

Hepatitis C Support Project Retrieved from

httpwwwhcvadvocateorghepatitisfactsheets_pdfFibrosispdf

Juergen

Braun Karl Braun and Ingolf

Sack Electromagnetic Actuator for

Generating Variably Oriented Shear Waves in MR Elastogrphy Magnetic

Resonance in Medicine 50220‐222(2003)

Kolipaka

A

Araoz

PA

McGee

KP Manduca

A

Ehman

RL (2010) Magnetic

resonance elastography

as a method for the assessment of effective myocardial

stiffness throughout the cardiac cycle

pubMed Retrieved from

httpwwwncbinlmnihgovpubmed20578052

McGee KP Lake D Mariappan

Y HubmayrRD Manduca

A Ansell K and Ehman

RL Calculation of shear

stiffness in noise dominated magnetic resonance elastography

data based on

principal frequency estimation 2011

Phys Med Biol

56

4291 34

Brain MR Elastography

Brain elasticity data can be used to detect certain diffuse diseases of the brain that are not well evaluated

by conventional imaging methods ‐Alzheimers‐Hydrocephalus‐focal brain lesions‐Multiple Sclerosis‐obtaining quantitative measurements of Elastic

modulus of cerebral tissue is of interest in biomechanical studies of brain trauma and in the

development of neurosurgery simulation techniques

24

MRE system designed for the brain

lsquoArsquo

applies vertical

displacement to the head

lsquoBrsquo

applies horizontal

displacement to the head

via a bite block

The θ

between the two can

be varied to image the

waves at various stages of

propagation

25

MRE system for a brain

Technical Challenges bullIntroducing s‐waves through the bony calvariumbullPerforming efficient sampling and processing of a 3D displacement field

Developed using a soft pillow like(passive) vibration (50 Hz) source to produce

intracranial s‐waves

26

Hydrocephalus

Obstruction of CSF flow in either

the lateral ventricles or the

subarachnoid space

Results in an increased size of

ventricles and therefore an

increase in intracranial pressure

(ICP)

MRI and CT assist in diagnosis

but they have limitations

These techniques only detect

ventricular enlargement which

can be confused with cerebral

atrophy or periventricular

leukomalacia (shrinkage of

periventricular white matter)

27

MRE diagnosis

Top normal patientBottom patient with hydrocephalus

28

MRE for detection of Cardiac disease states

HFPEF heart failure due to preserved ejection fraction

Hypertrophic cardiomyopathy

Load independent contractility

MI Myocardial infarction

29

Heart failure due to preserved Ejection fraction

30

HFpEf

Preserved ejection fraction

Efgt50

40 to 70 of heart failure

cases

Heart is contracting normally

but the ventricle walls are

stiff and do not relax

properly Less blood is

entering the heart during

systole

Patients with pEf also had

hypertension and coronary

artery diseases

31

Stiffness results

32

Future directions

Mechanical driver‐wave frequency‐multiple driver source

Data Processing

‐encoding process‐high‐speed 3D imaging‐new mathematical model for estimation of

tissue properties

33

References

Mauduca A Dynamic Magnetic Resonance Elastography Mayo Clinic College of

Medicine

Araoz

P Kolipaka

A mayo Clinic (Producer) (2010)Cardiac MRE [Web Video]

Retrieved from httpwwwyoutubecomwatchv=NyvjE5DpIis

Bachir T (2009)

Advanced MRI methods for assessment of chronic liver disease

Ehman R L (2009) Magnetic Resonance Elastography An emerging Tool for

Cellular Mechanobiology Mayo Clinic Rochester MN USA

Grenier

D Milot

L Peng

X Pilluel

F Beuf

O (2007) A Magnetic Resonance

Elastography

approach for liver investigationProceedings

for 29th

Annual

International Conference of the IEEE EMBS Lyon France

HighleyMan L Franciscus A (2011) Disease progression What is fibrosis

Hepatitis C Support Project Retrieved from

httpwwwhcvadvocateorghepatitisfactsheets_pdfFibrosispdf

Juergen

Braun Karl Braun and Ingolf

Sack Electromagnetic Actuator for

Generating Variably Oriented Shear Waves in MR Elastogrphy Magnetic

Resonance in Medicine 50220‐222(2003)

Kolipaka

A

Araoz

PA

McGee

KP Manduca

A

Ehman

RL (2010) Magnetic

resonance elastography

as a method for the assessment of effective myocardial

stiffness throughout the cardiac cycle

pubMed Retrieved from

httpwwwncbinlmnihgovpubmed20578052

McGee KP Lake D Mariappan

Y HubmayrRD Manduca

A Ansell K and Ehman

RL Calculation of shear

stiffness in noise dominated magnetic resonance elastography

data based on

principal frequency estimation 2011

Phys Med Biol

56

4291 34

MRE system designed for the brain

lsquoArsquo

applies vertical

displacement to the head

lsquoBrsquo

applies horizontal

displacement to the head

via a bite block

The θ

between the two can

be varied to image the

waves at various stages of

propagation

25

MRE system for a brain

Technical Challenges bullIntroducing s‐waves through the bony calvariumbullPerforming efficient sampling and processing of a 3D displacement field

Developed using a soft pillow like(passive) vibration (50 Hz) source to produce

intracranial s‐waves

26

Hydrocephalus

Obstruction of CSF flow in either

the lateral ventricles or the

subarachnoid space

Results in an increased size of

ventricles and therefore an

increase in intracranial pressure

(ICP)

MRI and CT assist in diagnosis

but they have limitations

These techniques only detect

ventricular enlargement which

can be confused with cerebral

atrophy or periventricular

leukomalacia (shrinkage of

periventricular white matter)

27

MRE diagnosis

Top normal patientBottom patient with hydrocephalus

28

MRE for detection of Cardiac disease states

HFPEF heart failure due to preserved ejection fraction

Hypertrophic cardiomyopathy

Load independent contractility

MI Myocardial infarction

29

Heart failure due to preserved Ejection fraction

30

HFpEf

Preserved ejection fraction

Efgt50

40 to 70 of heart failure

cases

Heart is contracting normally

but the ventricle walls are

stiff and do not relax

properly Less blood is

entering the heart during

systole

Patients with pEf also had

hypertension and coronary

artery diseases

31

Stiffness results

32

Future directions

Mechanical driver‐wave frequency‐multiple driver source

Data Processing

‐encoding process‐high‐speed 3D imaging‐new mathematical model for estimation of

tissue properties

33

References

Mauduca A Dynamic Magnetic Resonance Elastography Mayo Clinic College of

Medicine

Araoz

P Kolipaka

A mayo Clinic (Producer) (2010)Cardiac MRE [Web Video]

Retrieved from httpwwwyoutubecomwatchv=NyvjE5DpIis

Bachir T (2009)

Advanced MRI methods for assessment of chronic liver disease

Ehman R L (2009) Magnetic Resonance Elastography An emerging Tool for

Cellular Mechanobiology Mayo Clinic Rochester MN USA

Grenier

D Milot

L Peng

X Pilluel

F Beuf

O (2007) A Magnetic Resonance

Elastography

approach for liver investigationProceedings

for 29th

Annual

International Conference of the IEEE EMBS Lyon France

HighleyMan L Franciscus A (2011) Disease progression What is fibrosis

Hepatitis C Support Project Retrieved from

httpwwwhcvadvocateorghepatitisfactsheets_pdfFibrosispdf

Juergen

Braun Karl Braun and Ingolf

Sack Electromagnetic Actuator for

Generating Variably Oriented Shear Waves in MR Elastogrphy Magnetic

Resonance in Medicine 50220‐222(2003)

Kolipaka

A

Araoz

PA

McGee

KP Manduca

A

Ehman

RL (2010) Magnetic

resonance elastography

as a method for the assessment of effective myocardial

stiffness throughout the cardiac cycle

pubMed Retrieved from

httpwwwncbinlmnihgovpubmed20578052

McGee KP Lake D Mariappan

Y HubmayrRD Manduca

A Ansell K and Ehman

RL Calculation of shear

stiffness in noise dominated magnetic resonance elastography

data based on

principal frequency estimation 2011

Phys Med Biol

56

4291 34

MRE system for a brain

Technical Challenges bullIntroducing s‐waves through the bony calvariumbullPerforming efficient sampling and processing of a 3D displacement field

Developed using a soft pillow like(passive) vibration (50 Hz) source to produce

intracranial s‐waves

26

Hydrocephalus

Obstruction of CSF flow in either

the lateral ventricles or the

subarachnoid space

Results in an increased size of

ventricles and therefore an

increase in intracranial pressure

(ICP)

MRI and CT assist in diagnosis

but they have limitations

These techniques only detect

ventricular enlargement which

can be confused with cerebral

atrophy or periventricular

leukomalacia (shrinkage of

periventricular white matter)

27

MRE diagnosis

Top normal patientBottom patient with hydrocephalus

28

MRE for detection of Cardiac disease states

HFPEF heart failure due to preserved ejection fraction

Hypertrophic cardiomyopathy

Load independent contractility

MI Myocardial infarction

29

Heart failure due to preserved Ejection fraction

30

HFpEf

Preserved ejection fraction

Efgt50

40 to 70 of heart failure

cases

Heart is contracting normally

but the ventricle walls are

stiff and do not relax

properly Less blood is

entering the heart during

systole

Patients with pEf also had

hypertension and coronary

artery diseases

31

Stiffness results

32

Future directions

Mechanical driver‐wave frequency‐multiple driver source

Data Processing

‐encoding process‐high‐speed 3D imaging‐new mathematical model for estimation of

tissue properties

33

References

Mauduca A Dynamic Magnetic Resonance Elastography Mayo Clinic College of

Medicine

Araoz

P Kolipaka

A mayo Clinic (Producer) (2010)Cardiac MRE [Web Video]

Retrieved from httpwwwyoutubecomwatchv=NyvjE5DpIis

Bachir T (2009)

Advanced MRI methods for assessment of chronic liver disease

Ehman R L (2009) Magnetic Resonance Elastography An emerging Tool for

Cellular Mechanobiology Mayo Clinic Rochester MN USA

Grenier

D Milot

L Peng

X Pilluel

F Beuf

O (2007) A Magnetic Resonance

Elastography

approach for liver investigationProceedings

for 29th

Annual

International Conference of the IEEE EMBS Lyon France

HighleyMan L Franciscus A (2011) Disease progression What is fibrosis

Hepatitis C Support Project Retrieved from

httpwwwhcvadvocateorghepatitisfactsheets_pdfFibrosispdf

Juergen

Braun Karl Braun and Ingolf

Sack Electromagnetic Actuator for

Generating Variably Oriented Shear Waves in MR Elastogrphy Magnetic

Resonance in Medicine 50220‐222(2003)

Kolipaka

A

Araoz

PA

McGee

KP Manduca

A

Ehman

RL (2010) Magnetic

resonance elastography

as a method for the assessment of effective myocardial

stiffness throughout the cardiac cycle

pubMed Retrieved from

httpwwwncbinlmnihgovpubmed20578052

McGee KP Lake D Mariappan

Y HubmayrRD Manduca

A Ansell K and Ehman

RL Calculation of shear

stiffness in noise dominated magnetic resonance elastography

data based on

principal frequency estimation 2011

Phys Med Biol

56

4291 34

Hydrocephalus

Obstruction of CSF flow in either

the lateral ventricles or the

subarachnoid space

Results in an increased size of

ventricles and therefore an

increase in intracranial pressure

(ICP)

MRI and CT assist in diagnosis

but they have limitations

These techniques only detect

ventricular enlargement which

can be confused with cerebral

atrophy or periventricular

leukomalacia (shrinkage of

periventricular white matter)

27

MRE diagnosis

Top normal patientBottom patient with hydrocephalus

28

MRE for detection of Cardiac disease states

HFPEF heart failure due to preserved ejection fraction

Hypertrophic cardiomyopathy

Load independent contractility

MI Myocardial infarction

29

Heart failure due to preserved Ejection fraction

30

HFpEf

Preserved ejection fraction

Efgt50

40 to 70 of heart failure

cases

Heart is contracting normally

but the ventricle walls are

stiff and do not relax

properly Less blood is

entering the heart during

systole

Patients with pEf also had

hypertension and coronary

artery diseases

31

Stiffness results

32

Future directions

Mechanical driver‐wave frequency‐multiple driver source

Data Processing

‐encoding process‐high‐speed 3D imaging‐new mathematical model for estimation of

tissue properties

33

References

Mauduca A Dynamic Magnetic Resonance Elastography Mayo Clinic College of

Medicine

Araoz

P Kolipaka

A mayo Clinic (Producer) (2010)Cardiac MRE [Web Video]

Retrieved from httpwwwyoutubecomwatchv=NyvjE5DpIis

Bachir T (2009)

Advanced MRI methods for assessment of chronic liver disease

Ehman R L (2009) Magnetic Resonance Elastography An emerging Tool for

Cellular Mechanobiology Mayo Clinic Rochester MN USA

Grenier

D Milot

L Peng

X Pilluel

F Beuf

O (2007) A Magnetic Resonance

Elastography

approach for liver investigationProceedings

for 29th

Annual

International Conference of the IEEE EMBS Lyon France

HighleyMan L Franciscus A (2011) Disease progression What is fibrosis

Hepatitis C Support Project Retrieved from

httpwwwhcvadvocateorghepatitisfactsheets_pdfFibrosispdf

Juergen

Braun Karl Braun and Ingolf

Sack Electromagnetic Actuator for

Generating Variably Oriented Shear Waves in MR Elastogrphy Magnetic

Resonance in Medicine 50220‐222(2003)

Kolipaka

A

Araoz

PA

McGee

KP Manduca

A

Ehman

RL (2010) Magnetic

resonance elastography

as a method for the assessment of effective myocardial

stiffness throughout the cardiac cycle

pubMed Retrieved from

httpwwwncbinlmnihgovpubmed20578052

McGee KP Lake D Mariappan

Y HubmayrRD Manduca

A Ansell K and Ehman

RL Calculation of shear

stiffness in noise dominated magnetic resonance elastography

data based on

principal frequency estimation 2011

Phys Med Biol

56

4291 34

MRE diagnosis

Top normal patientBottom patient with hydrocephalus

28

MRE for detection of Cardiac disease states

HFPEF heart failure due to preserved ejection fraction

Hypertrophic cardiomyopathy

Load independent contractility

MI Myocardial infarction

29

Heart failure due to preserved Ejection fraction

30

HFpEf

Preserved ejection fraction

Efgt50

40 to 70 of heart failure

cases

Heart is contracting normally

but the ventricle walls are

stiff and do not relax

properly Less blood is

entering the heart during

systole

Patients with pEf also had

hypertension and coronary

artery diseases

31

Stiffness results

32

Future directions

Mechanical driver‐wave frequency‐multiple driver source

Data Processing

‐encoding process‐high‐speed 3D imaging‐new mathematical model for estimation of

tissue properties

33

References

Mauduca A Dynamic Magnetic Resonance Elastography Mayo Clinic College of

Medicine

Araoz

P Kolipaka

A mayo Clinic (Producer) (2010)Cardiac MRE [Web Video]

Retrieved from httpwwwyoutubecomwatchv=NyvjE5DpIis

Bachir T (2009)

Advanced MRI methods for assessment of chronic liver disease

Ehman R L (2009) Magnetic Resonance Elastography An emerging Tool for

Cellular Mechanobiology Mayo Clinic Rochester MN USA

Grenier

D Milot

L Peng

X Pilluel

F Beuf

O (2007) A Magnetic Resonance

Elastography

approach for liver investigationProceedings

for 29th

Annual

International Conference of the IEEE EMBS Lyon France

HighleyMan L Franciscus A (2011) Disease progression What is fibrosis

Hepatitis C Support Project Retrieved from

httpwwwhcvadvocateorghepatitisfactsheets_pdfFibrosispdf

Juergen

Braun Karl Braun and Ingolf

Sack Electromagnetic Actuator for

Generating Variably Oriented Shear Waves in MR Elastogrphy Magnetic

Resonance in Medicine 50220‐222(2003)

Kolipaka

A

Araoz

PA

McGee

KP Manduca

A

Ehman

RL (2010) Magnetic

resonance elastography

as a method for the assessment of effective myocardial

stiffness throughout the cardiac cycle

pubMed Retrieved from

httpwwwncbinlmnihgovpubmed20578052

McGee KP Lake D Mariappan

Y HubmayrRD Manduca

A Ansell K and Ehman

RL Calculation of shear

stiffness in noise dominated magnetic resonance elastography

data based on

principal frequency estimation 2011

Phys Med Biol

56

4291 34

MRE for detection of Cardiac disease states

HFPEF heart failure due to preserved ejection fraction

Hypertrophic cardiomyopathy

Load independent contractility

MI Myocardial infarction

29

Heart failure due to preserved Ejection fraction

30

HFpEf

Preserved ejection fraction

Efgt50

40 to 70 of heart failure

cases

Heart is contracting normally

but the ventricle walls are

stiff and do not relax

properly Less blood is

entering the heart during

systole

Patients with pEf also had

hypertension and coronary

artery diseases

31

Stiffness results

32

Future directions

Mechanical driver‐wave frequency‐multiple driver source

Data Processing

‐encoding process‐high‐speed 3D imaging‐new mathematical model for estimation of

tissue properties

33

References

Mauduca A Dynamic Magnetic Resonance Elastography Mayo Clinic College of

Medicine

Araoz

P Kolipaka

A mayo Clinic (Producer) (2010)Cardiac MRE [Web Video]

Retrieved from httpwwwyoutubecomwatchv=NyvjE5DpIis

Bachir T (2009)

Advanced MRI methods for assessment of chronic liver disease

Ehman R L (2009) Magnetic Resonance Elastography An emerging Tool for

Cellular Mechanobiology Mayo Clinic Rochester MN USA

Grenier

D Milot

L Peng

X Pilluel

F Beuf

O (2007) A Magnetic Resonance

Elastography

approach for liver investigationProceedings

for 29th

Annual

International Conference of the IEEE EMBS Lyon France

HighleyMan L Franciscus A (2011) Disease progression What is fibrosis

Hepatitis C Support Project Retrieved from

httpwwwhcvadvocateorghepatitisfactsheets_pdfFibrosispdf

Juergen

Braun Karl Braun and Ingolf

Sack Electromagnetic Actuator for

Generating Variably Oriented Shear Waves in MR Elastogrphy Magnetic

Resonance in Medicine 50220‐222(2003)

Kolipaka

A

Araoz

PA

McGee

KP Manduca

A

Ehman

RL (2010) Magnetic

resonance elastography

as a method for the assessment of effective myocardial

stiffness throughout the cardiac cycle

pubMed Retrieved from

httpwwwncbinlmnihgovpubmed20578052

McGee KP Lake D Mariappan

Y HubmayrRD Manduca

A Ansell K and Ehman

RL Calculation of shear

stiffness in noise dominated magnetic resonance elastography

data based on

principal frequency estimation 2011

Phys Med Biol

56

4291 34

Heart failure due to preserved Ejection fraction

30

HFpEf

Preserved ejection fraction

Efgt50

40 to 70 of heart failure

cases

Heart is contracting normally

but the ventricle walls are

stiff and do not relax

properly Less blood is

entering the heart during

systole

Patients with pEf also had

hypertension and coronary

artery diseases

31

Stiffness results

32

Future directions

Mechanical driver‐wave frequency‐multiple driver source

Data Processing

‐encoding process‐high‐speed 3D imaging‐new mathematical model for estimation of

tissue properties

33

References

Mauduca A Dynamic Magnetic Resonance Elastography Mayo Clinic College of

Medicine

Araoz

P Kolipaka

A mayo Clinic (Producer) (2010)Cardiac MRE [Web Video]

Retrieved from httpwwwyoutubecomwatchv=NyvjE5DpIis

Bachir T (2009)

Advanced MRI methods for assessment of chronic liver disease

Ehman R L (2009) Magnetic Resonance Elastography An emerging Tool for

Cellular Mechanobiology Mayo Clinic Rochester MN USA

Grenier

D Milot

L Peng

X Pilluel

F Beuf

O (2007) A Magnetic Resonance

Elastography

approach for liver investigationProceedings

for 29th

Annual

International Conference of the IEEE EMBS Lyon France

HighleyMan L Franciscus A (2011) Disease progression What is fibrosis

Hepatitis C Support Project Retrieved from

httpwwwhcvadvocateorghepatitisfactsheets_pdfFibrosispdf

Juergen

Braun Karl Braun and Ingolf

Sack Electromagnetic Actuator for

Generating Variably Oriented Shear Waves in MR Elastogrphy Magnetic

Resonance in Medicine 50220‐222(2003)

Kolipaka

A

Araoz

PA

McGee

KP Manduca

A

Ehman

RL (2010) Magnetic

resonance elastography

as a method for the assessment of effective myocardial

stiffness throughout the cardiac cycle

pubMed Retrieved from

httpwwwncbinlmnihgovpubmed20578052

McGee KP Lake D Mariappan

Y HubmayrRD Manduca

A Ansell K and Ehman

RL Calculation of shear

stiffness in noise dominated magnetic resonance elastography

data based on

principal frequency estimation 2011

Phys Med Biol

56

4291 34

HFpEf

Preserved ejection fraction

Efgt50

40 to 70 of heart failure

cases

Heart is contracting normally

but the ventricle walls are

stiff and do not relax

properly Less blood is

entering the heart during

systole

Patients with pEf also had

hypertension and coronary

artery diseases

31

Stiffness results

32

Future directions

Mechanical driver‐wave frequency‐multiple driver source

Data Processing

‐encoding process‐high‐speed 3D imaging‐new mathematical model for estimation of

tissue properties

33

References

Mauduca A Dynamic Magnetic Resonance Elastography Mayo Clinic College of

Medicine

Araoz

P Kolipaka

A mayo Clinic (Producer) (2010)Cardiac MRE [Web Video]

Retrieved from httpwwwyoutubecomwatchv=NyvjE5DpIis

Bachir T (2009)

Advanced MRI methods for assessment of chronic liver disease

Ehman R L (2009) Magnetic Resonance Elastography An emerging Tool for

Cellular Mechanobiology Mayo Clinic Rochester MN USA

Grenier

D Milot

L Peng

X Pilluel

F Beuf

O (2007) A Magnetic Resonance

Elastography

approach for liver investigationProceedings

for 29th

Annual

International Conference of the IEEE EMBS Lyon France

HighleyMan L Franciscus A (2011) Disease progression What is fibrosis

Hepatitis C Support Project Retrieved from

httpwwwhcvadvocateorghepatitisfactsheets_pdfFibrosispdf

Juergen

Braun Karl Braun and Ingolf

Sack Electromagnetic Actuator for

Generating Variably Oriented Shear Waves in MR Elastogrphy Magnetic

Resonance in Medicine 50220‐222(2003)

Kolipaka

A

Araoz

PA

McGee

KP Manduca

A

Ehman

RL (2010) Magnetic

resonance elastography

as a method for the assessment of effective myocardial

stiffness throughout the cardiac cycle

pubMed Retrieved from

httpwwwncbinlmnihgovpubmed20578052

McGee KP Lake D Mariappan

Y HubmayrRD Manduca

A Ansell K and Ehman

RL Calculation of shear

stiffness in noise dominated magnetic resonance elastography

data based on

principal frequency estimation 2011

Phys Med Biol

56

4291 34

Stiffness results

32

Future directions

Mechanical driver‐wave frequency‐multiple driver source

Data Processing

‐encoding process‐high‐speed 3D imaging‐new mathematical model for estimation of

tissue properties

33

References

Mauduca A Dynamic Magnetic Resonance Elastography Mayo Clinic College of

Medicine

Araoz

P Kolipaka

A mayo Clinic (Producer) (2010)Cardiac MRE [Web Video]

Retrieved from httpwwwyoutubecomwatchv=NyvjE5DpIis

Bachir T (2009)

Advanced MRI methods for assessment of chronic liver disease

Ehman R L (2009) Magnetic Resonance Elastography An emerging Tool for

Cellular Mechanobiology Mayo Clinic Rochester MN USA

Grenier

D Milot

L Peng

X Pilluel

F Beuf

O (2007) A Magnetic Resonance

Elastography

approach for liver investigationProceedings

for 29th

Annual

International Conference of the IEEE EMBS Lyon France

HighleyMan L Franciscus A (2011) Disease progression What is fibrosis

Hepatitis C Support Project Retrieved from

httpwwwhcvadvocateorghepatitisfactsheets_pdfFibrosispdf

Juergen

Braun Karl Braun and Ingolf

Sack Electromagnetic Actuator for

Generating Variably Oriented Shear Waves in MR Elastogrphy Magnetic

Resonance in Medicine 50220‐222(2003)

Kolipaka

A

Araoz

PA

McGee

KP Manduca

A

Ehman

RL (2010) Magnetic

resonance elastography

as a method for the assessment of effective myocardial

stiffness throughout the cardiac cycle

pubMed Retrieved from

httpwwwncbinlmnihgovpubmed20578052

McGee KP Lake D Mariappan

Y HubmayrRD Manduca

A Ansell K and Ehman

RL Calculation of shear

stiffness in noise dominated magnetic resonance elastography

data based on

principal frequency estimation 2011

Phys Med Biol

56

4291 34

Future directions

Mechanical driver‐wave frequency‐multiple driver source

Data Processing

‐encoding process‐high‐speed 3D imaging‐new mathematical model for estimation of

tissue properties

33

References

Mauduca A Dynamic Magnetic Resonance Elastography Mayo Clinic College of

Medicine

Araoz

P Kolipaka

A mayo Clinic (Producer) (2010)Cardiac MRE [Web Video]

Retrieved from httpwwwyoutubecomwatchv=NyvjE5DpIis

Bachir T (2009)

Advanced MRI methods for assessment of chronic liver disease

Ehman R L (2009) Magnetic Resonance Elastography An emerging Tool for

Cellular Mechanobiology Mayo Clinic Rochester MN USA

Grenier

D Milot

L Peng

X Pilluel

F Beuf

O (2007) A Magnetic Resonance

Elastography

approach for liver investigationProceedings

for 29th

Annual

International Conference of the IEEE EMBS Lyon France

HighleyMan L Franciscus A (2011) Disease progression What is fibrosis

Hepatitis C Support Project Retrieved from

httpwwwhcvadvocateorghepatitisfactsheets_pdfFibrosispdf

Juergen

Braun Karl Braun and Ingolf

Sack Electromagnetic Actuator for

Generating Variably Oriented Shear Waves in MR Elastogrphy Magnetic

Resonance in Medicine 50220‐222(2003)

Kolipaka

A

Araoz

PA

McGee

KP Manduca

A

Ehman

RL (2010) Magnetic

resonance elastography

as a method for the assessment of effective myocardial

stiffness throughout the cardiac cycle

pubMed Retrieved from

httpwwwncbinlmnihgovpubmed20578052

McGee KP Lake D Mariappan

Y HubmayrRD Manduca

A Ansell K and Ehman

RL Calculation of shear

stiffness in noise dominated magnetic resonance elastography

data based on

principal frequency estimation 2011

Phys Med Biol

56

4291 34

References

Mauduca A Dynamic Magnetic Resonance Elastography Mayo Clinic College of

Medicine

Araoz

P Kolipaka

A mayo Clinic (Producer) (2010)Cardiac MRE [Web Video]

Retrieved from httpwwwyoutubecomwatchv=NyvjE5DpIis

Bachir T (2009)

Advanced MRI methods for assessment of chronic liver disease

Ehman R L (2009) Magnetic Resonance Elastography An emerging Tool for

Cellular Mechanobiology Mayo Clinic Rochester MN USA

Grenier

D Milot

L Peng

X Pilluel

F Beuf

O (2007) A Magnetic Resonance

Elastography

approach for liver investigationProceedings

for 29th

Annual

International Conference of the IEEE EMBS Lyon France

HighleyMan L Franciscus A (2011) Disease progression What is fibrosis

Hepatitis C Support Project Retrieved from

httpwwwhcvadvocateorghepatitisfactsheets_pdfFibrosispdf

Juergen

Braun Karl Braun and Ingolf

Sack Electromagnetic Actuator for

Generating Variably Oriented Shear Waves in MR Elastogrphy Magnetic

Resonance in Medicine 50220‐222(2003)

Kolipaka

A

Araoz

PA

McGee

KP Manduca

A

Ehman

RL (2010) Magnetic

resonance elastography

as a method for the assessment of effective myocardial

stiffness throughout the cardiac cycle

pubMed Retrieved from

httpwwwncbinlmnihgovpubmed20578052

McGee KP Lake D Mariappan

Y HubmayrRD Manduca

A Ansell K and Ehman

RL Calculation of shear

stiffness in noise dominated magnetic resonance elastography

data based on

principal frequency estimation 2011

Phys Med Biol

56

4291 34

References

Owan

TE Hodge DO Herges

RM Jacobsen SJ Roger V Redfield MM (2006)

The new England Journal of MedicineTrends

in prevelance

and outcome of

Heart failure with preserved Ejection Fraction Original article Retrieved from

wwwnejmorg

S Papazoglou U Hamhaber J Braun I and I Sack Algebraic Helmholtz inversion

in planar magnetic resonance elastography Phys Med Biol 53(2008)3147‐3158

Paulsen KDPattison

AJ Perreard LM Weaver JB Roberts DW

(2011)Hydrocephalus detection using intrinsically‐activated mre Academic paper

Thayer School of Engineering Darthmouth

College Hanover New Hampshire

US Retrieved from

httpsubmissionsmiracdcomismrm2011proceedingsfiles41pdf

Zion Tsz

Ho Tse Yum Ji

Chan Henning Janssen Abbi

Hamed Ian Young and

Michael Lamperth Piezoelectric actuator design for MR elastography

implementation and vibration issues Int

J Med Robotics Comput

Assist Surg

2011 7353‐360

YOGESH K MARIAPPAN KEVIN J GLASER AND RICHARD L EHMAN

Magnetic Resonance Elastography A review Clin Anat 23497ndash511(2010)

Y Zheng G Li M Chen Q C C Chan S G Hu X N Zhao R L Ehman E Y

Lam and E S Yang Magnetic Resonance Elastography

with Twin Pneumatic

Drivers for Wave Compensation IEEE(2007)

35