Chen Lin, PhD - Indiana University Bloomingtonmri/CE/slides/MR Perfusion... · Chen Lin, PhD DSC...
8
7/14/2009 1 MR Perfusion Imaging Techniques and Applications Chen Lin, PhD Indiana University School of Medicine & Clarian Health Partners Outlines • Perfusion Modeling • Methods of Perfusion measurements and clinical protocols. • Perfusion Quantification and parametric maps. • Examples of perfusion weighted imaging. Chen Lin, PhD Perfusion • Deliver oxygen and nutrients to the cells • Affected by pathological and physiological conditions, such as tumor angio-genesis, stroke and infarct, vascular wall changes. Chen Lin, PhD MR Perfusion Imaging Methods • Dynamic Susceptibility Contrast (DSC) MRI Perfusion – GRE-EPI (T2* weighted) – SE-EPI (T2 weighted) • Dynamic Contrast Enhanced (DCE) MRI Perfusion – Spoiled Fast Gradient Echo (T1 Weighted) • Arterial Spin Labeling • Intra Voxel Incoherence Chen Lin, PhD DSC Perfusion Model and Parameters • Blood Flow (ml of blood / gram of tissue / sec) • Blood Volume (ml of blood / gram of tissue) • Mean Transit Time (MTT) (sec) Chen Lin, PhD v Artery Vein CBF = CBV / MTT Capillary Bed Typical DSC Perfusion Protocol • Single shot GRE-EPI or SE-EPI • TE = 30 – 60 ms (GRE-EPI) or 50 – 80 ms (SE- EPI) • TR = min. ( < 2 sec depends on number of slices ) • TA = 90 - 120 sec. or ~ 100 time points • Contrast dose = 0.1 – 0.2 mmol/kg • Injection rate: 3 – 5 ml/sec with 20 ml saline flush. Chen Lin, PhD
Transcript of Chen Lin, PhD - Indiana University Bloomingtonmri/CE/slides/MR Perfusion... · Chen Lin, PhD DSC...
7142009
1
MR Perfusion Imaging Techniques and Applications
Chen Lin PhD
Indiana University School of Medicine amp Clarian Health Partners
Outlines
bull Perfusion Modeling
bull Methods of Perfusion measurements and clinical protocols
bull Perfusion Quantification and parametric maps
bull Examples of perfusion weighted imaging
Chen Lin PhD
Perfusion
bull Deliver oxygen and nutrients to the cells
bull Affected by pathological and physiological conditions such as tumor angio-genesis stroke and infarct vascular wall changes
Chen Lin PhD
MR Perfusion Imaging Methods
bull Dynamic Susceptibility Contrast (DSC) MRI Perfusion
ndash GRE-EPI (T2 weighted)
ndash SE-EPI (T2 weighted)
bull Dynamic Contrast Enhanced (DCE) MRI Perfusion
ndash Spoiled Fast Gradient Echo (T1 Weighted)
bull Arterial Spin Labeling
bull Intra Voxel Incoherence
Chen Lin PhD
DSC Perfusion Model and Parameters
bull Blood Flow (ml of blood gram of tissue sec)
bull Blood Volume (ml of blood gram of tissue)
bull Mean Transit Time (MTT) (sec)
Chen Lin PhD
v
Artery Vein
CBF = CBV MTT
Capillary Bed
Typical DSC Perfusion Protocol
bull Single shot GRE-EPI or SE-EPI
bull TE = 30 ndash 60 ms (GRE-EPI) or 50 ndash 80 ms (SE-EPI)
bull TR = min ( lt 2 sec depends on number of slices )
bull TA = 90 - 120 sec or ~ 100 time points
bull Contrast dose = 01 ndash 02 mmolkg
bull Injection rate 3 ndash 5 mlsec with 20 ml saline flush
Chen Lin PhD
7142009
2
SE-EPI vs GRE-EPI for DSC PWI
bull SE-EPI signal (T2 dependent) is more specific to microvasculature while GRE-EPI signal (T2 dependent) is also sensitive to larger vessels
bull GRE-EPI provides greater sensitivity and coverage (more slices for same TR)
Chen Lin PhD
DSC Perfusion Imaging
Time
Signal
Percent Baseline at Peak
Time To Peak
Time To Minimum
Mean Transit Time
Negative Enhancement Integral
Baseline
Chen Lin PhD
DSC Post-processing (Siemens)
1 Define a ROI for selecting AIF 2 Select an AIF among the signal ndash
time curves for all the voxels in the ROI
3 Set time ranges in the AIF4 Calculate PWI maps
Chen Lin PhD
Perfusion Example
T2w
FLAIR
Chen Lin PhD
SWI
GRE-EPI
DSC Perfusion Maps
Relative Mean Transit Time
(relMTT)
Percent Baseline at Peak (PBP)
Time to Peak(TTP)
Negative Enhancement
Integral(NEI)
Chen Lin PhD
DWI PWI Mismatch in Stoke
DWI 4hr rCBV 4hr
Courtesy of Sorenson MGH Chen Lin PhD
7142009
3
Tumor versus Radiation Necrosis
T2w rCBV
Chen Lin PhD
Leakage and Permeability
Chen Lin PhD
Typical DCE Perfusion Protocol
bull Spoiled 2D or 3D gradient echo (SPGR or FLASH)
bull TE = min
bull TR = min ( typically 4 ndash 10 sec)
bull FA = 30 ndash 40 deg
bull TA = several minutes
bull Contrast dose = 01 ndash 02 mmolkg
bull Injection rate 3 ndash 5 mlsec with 20 ml saline flush
bull Measure baseline T1 with different FAsChen Lin PhD
DCE-MRI Evaluation
Qualitative - shape of signal intensity (SI) data curve
Semi-quantitative - indices that describe one or more parts of SI or [Gd] curves
Upslope gradient max amplitude washout rate or area under curve at a fixed time point
True quantitative - indices from contrast medium concentration changes using pharmacokinetic modelling
Chen Lin PhD
Type I(semi-necrotic with reactive changes)
Type II(viable tumor)
Type III(rapidly proliferating
tumor edge)
(Taylor and Reddick Adv Drug Del Rev 2000)
Qualitative Evaluation of DCE-MRI time Curve
Chen Lin PhD
DCE Perfusion Modelling
( )( ) ( )transt
p ep t
trans
ep
dC tK C t k C t
dt
Kk
Ve
Chen Lin PhD
Blood plasma
Cp
Ct = Ce Ve
Ve Ce
Ktrans
Kep
Tumor Extracellular
Space
NormalExtracellular
Space
7142009
4
Quantification of Contrast Concentration
R1(t) = R1(0) + C(t) Rbull R1(t) Longitudinal relaxation rate 1T1(t) at a given time
point t can be determined from the ratio of signal intensities between T1w and PDw images SI(T1w)SI(PDw)
bull R1(0) Longitudinal relaxation rate 1T1(0) at baseline ie before contrast arrival can also be determined from SI(T1w)SI(PDw) at baseline
bull R Relaxivity of the contrast agent ie Gd-DTPA
bull C(t) Contrast concentration at a given time t can be derived
bull Ct(t) Tissue contrast concentration curve
bull Cp(t) Blood contrast concentration curve arterial input function (AIF)
Chen Lin PhD
Quantitative analysis with pharmacokinetic modelling
bull Advantagesndash Whole curve shape is analysed
ndash Biologically relevant physiological parameters
ndash Independent of scanner strength manufacturer and imaging routines
ndash Enables valid comparisons of serial measurements and data exchange between different imaging centres
bull Disadvantagesndash Data acquisition and analysis is more complex
ndash Lack of commercial software for analysis
ndash Models may not fit the data observed
Chen Lin PhD
DCE Perfusion of Pancreatic Tumor
Chen Lin PhD
DCE Perfusion of Pancreatic Tumor
Chen Lin PhD
PWI with Arterial Spinning Labeling
bull Tagged blood flows through vasculature and exchanges with tissue
bull Change total tissue magnetization in slice (1-2) compared to control
bull ldquoControlrdquo ndash ldquoLabeledrdquo CBF
Artery Vein
Chen Lin PhD
Labeling Techniques
bull Continuous or Steady-state ASL (CASL)
ndash Saturation (Detre 1992)
ndash Inversion (Williams 1992) with flow-driven adiabatic inversion pulse
ndash Labeling with 2nd coil
bull Pulsed ASL (uses a bolus of labeled spins) (PASL)
ndash STAR TILT PICORE FAIR hellip
bull Velocity Selective ASL
Chen Lin PhD
7142009
5
CASL with Dedicated Labeling Coil
bull Reduce SAR
bull Reduce MT effect
bull Additional hardware
Imaging Plane
Labeling Coil
Chen Lin PhD
Typical PASL Design
M0 Label Control Label ControlLabelControl
Control - Label Control - Label Control - LabelDM
CBF = 3x108 l [mlg] a [] TI1 Exp(TI2T1blood) DMM0
Image
Acquisition
Module
TI2
TI1Labeling
Control
Module
Bolus Cut-off Module
Chen Lin PhD
Chen Lin PhD
QUIPSS amp QUIPSS II
bull QUantitative Imaging of Perfusion using a Single Subtraction
bull Use saturation pulses to shave the leading or trailing edge of the bolus so the transit time is the same
Image
Acquisition
Module
TI2
TI1Labeling
Control
Module
900 900
ASL Image Acquisition Mode
bull 2D single and multiple slices
bull 3D (long acquisition time)
Chen Lin PhD
ASL Image Acquisition Methods
bull GRESE EPI (STAR + EPI Edelman 1994 FAIR + EPI Kim 1995)
bull HASTE (STAR + HAlf-fourier Single-shot Turbo spin Echo Chen 1997)
bull GRASE (FAIR + GRadient echo And Spin Echo Crelier 1999)
bull TrueFISP (FAIR + True Fast Imaging with Steady-state Precession Boss 2007)
Chen Lin PhD
PASL Issues and Optimization
bull SNR and Susceptibility artifacts
ndash Use short TE amp ETL
bull T1 Relaxation effect amp Transit Time Difference
ndash Decay of magnetization from the tagging location to imaging location
ndash The transit time of leading and trailing edge of the labeled bolus are different
bull Arterial Signal
ndash Apply a small bipolar diffusion weighting gradient b ~ 2 smm2
Chen Lin PhD
7142009
6
PASL Issues and Optimization
bull Physiological Noise
ndash Reduction with background suppression
ndash Model and correct the physiological fluctuation with statistical analysis (GLM)
bull MT effect
ndash Suppression at imaging location from off-resonance effect of labeling pulse Asymmetric with respect to frequency shift
bull Eddy Current Compensation
ndash Maintain the similar gradient waveform between tagging and control
Chen Lin PhD
MT Effect amp Labeling Schemes
bull STAR (Signal Targeting with Alternating Radio Frequency)
bull PICORE (Proximal Inversion with a Control for Off-resonance Effect) (Wong 1997)
bull TILT (Transfer Insensitive Labeling Technique) (Gobay 1999)
bull FAIR (Flow-sensitive Alternating Inversion Recovery) (Kim 1995)
Chen Lin PhD
PICORE
Tagging
Control
1800
1800
wt = wi + Dw
wc = wi + Dw
Gt = 0
Chen Lin PhD
FAIR
Tagging
Control
1800
1800
wt = wi
wc = wi
Gt = 0Chen Lin PhD
ASL Applications
bull Quantification of rest state CBF and study the perfusion changes from a disease or treatmentintervention
ndash Tumor Stroke Alzheimerrsquos Disease vascular disorder etc hellip
ndash Infant brain development (Wang Neuroimage 2008) amp Aging (Biagi JMRI 2007)
ndash Uncoupling contributions to BOLD fMRI
Chen Lin PhD
AVM
T2wDSCrMTT
ASLrCBF
DSCNEI
Chen Lin PhD
7142009
7
T2-weighted
Ischemia (RgtL)
Pre-op ASL
Hypo-perfusion (RgtL)
Post-op ASL
Bilateral increase
ASL perfusion correlated better with cognitive deficits than structural MRI
Jefferson AJNR 2006
Intracranial Stenosis
Chen Lin PhD
Du A T et al Neurology 200667125-1220
Frontotemporal Dementia (FTD) and Alzheimer Disease (AD)
FTD and AD display different spatial distributions of hypo-perfusion Chen Lin PhD
ASL Perfusion based fMRI
bull Perfusion fMRI ie Quantification of functional related dynamic CBF changes
ndashConventional stimulustasks such as sensory-motor memory speech tasks similar to those in BOLD fMRI
ndashPharmacological stimulus such caffeine or cocaine
ndashBehaviorenvironment changes such as sleep deprivation pain
Chen Lin PhD
Xu G et al Neurology 2007
CBF changes of congnitively normal (CN) amp amnestic mild cognitive impairment (aMCI) groups
A significant regional CBF percent increase occurred in the region of the right parahippocampus during the sustained memory-encoding period in the CN group but not in the aMCI group
Chen Lin PhD
ASL versus BOLD for fMRIbull Much lower SNR
1-2 signal change in ASL versus 5-10 in BOLD
bull Direct measure of CBF changesBOLD is coupled with CBF CMRO2 CBV
bull More localized and quantitative
bull Better long-term stability and reproducibilityLow frequency fMRI
bull Insensitive to magnetic susceptibility effectsUse short TE and susceptibility insensitive image acquisition
bull Less inter-subject variabilityAllows group analysis long term and multisite study
Chen Lin PhD
ASL versus DSC
bull Lower SNR and therefore typical acquired with lower resolution
bull More susceptible to physiological variation
bull Less coverage
bull Non-invasive
Chen Lin PhD
7142009
8
ASL Outside of the Brain
bull Kidney (Warmuth JMRI 2007)
bull Muscle (Frouin MRM 2006)
bull Lung (Bolar MRM 2006)
Chen Lin PhD
Getting more from Diffusion Attenuation Curve
Ln(S)
b
Perfusion
S = Sb=0 [ (1-f) endashbD + f endashb(D+D) ]
b = 50
b = 500
Chen Lin PhD
Intra Voxel Incoherence Imaging
Luciani A et al Radiology 2008 Dec249(3)891-9
DWI b=50 D
D fChen Lin PhD
Thank you
7142009
2
SE-EPI vs GRE-EPI for DSC PWI
bull SE-EPI signal (T2 dependent) is more specific to microvasculature while GRE-EPI signal (T2 dependent) is also sensitive to larger vessels
bull GRE-EPI provides greater sensitivity and coverage (more slices for same TR)
Chen Lin PhD
DSC Perfusion Imaging
Time
Signal
Percent Baseline at Peak
Time To Peak
Time To Minimum
Mean Transit Time
Negative Enhancement Integral
Baseline
Chen Lin PhD
DSC Post-processing (Siemens)
1 Define a ROI for selecting AIF 2 Select an AIF among the signal ndash
time curves for all the voxels in the ROI
3 Set time ranges in the AIF4 Calculate PWI maps
Chen Lin PhD
Perfusion Example
T2w
FLAIR
Chen Lin PhD
SWI
GRE-EPI
DSC Perfusion Maps
Relative Mean Transit Time
(relMTT)
Percent Baseline at Peak (PBP)
Time to Peak(TTP)
Negative Enhancement
Integral(NEI)
Chen Lin PhD
DWI PWI Mismatch in Stoke
DWI 4hr rCBV 4hr
Courtesy of Sorenson MGH Chen Lin PhD
7142009
3
Tumor versus Radiation Necrosis
T2w rCBV
Chen Lin PhD
Leakage and Permeability
Chen Lin PhD
Typical DCE Perfusion Protocol
bull Spoiled 2D or 3D gradient echo (SPGR or FLASH)
bull TE = min
bull TR = min ( typically 4 ndash 10 sec)
bull FA = 30 ndash 40 deg
bull TA = several minutes
bull Contrast dose = 01 ndash 02 mmolkg
bull Injection rate 3 ndash 5 mlsec with 20 ml saline flush
bull Measure baseline T1 with different FAsChen Lin PhD
DCE-MRI Evaluation
Qualitative - shape of signal intensity (SI) data curve
Semi-quantitative - indices that describe one or more parts of SI or [Gd] curves
Upslope gradient max amplitude washout rate or area under curve at a fixed time point
True quantitative - indices from contrast medium concentration changes using pharmacokinetic modelling
Chen Lin PhD
Type I(semi-necrotic with reactive changes)
Type II(viable tumor)
Type III(rapidly proliferating
tumor edge)
(Taylor and Reddick Adv Drug Del Rev 2000)
Qualitative Evaluation of DCE-MRI time Curve
Chen Lin PhD
DCE Perfusion Modelling
( )( ) ( )transt
p ep t
trans
ep
dC tK C t k C t
dt
Kk
Ve
Chen Lin PhD
Blood plasma
Cp
Ct = Ce Ve
Ve Ce
Ktrans
Kep
Tumor Extracellular
Space
NormalExtracellular
Space
7142009
4
Quantification of Contrast Concentration
R1(t) = R1(0) + C(t) Rbull R1(t) Longitudinal relaxation rate 1T1(t) at a given time
point t can be determined from the ratio of signal intensities between T1w and PDw images SI(T1w)SI(PDw)
bull R1(0) Longitudinal relaxation rate 1T1(0) at baseline ie before contrast arrival can also be determined from SI(T1w)SI(PDw) at baseline
bull R Relaxivity of the contrast agent ie Gd-DTPA
bull C(t) Contrast concentration at a given time t can be derived
bull Ct(t) Tissue contrast concentration curve
bull Cp(t) Blood contrast concentration curve arterial input function (AIF)
Chen Lin PhD
Quantitative analysis with pharmacokinetic modelling
bull Advantagesndash Whole curve shape is analysed
ndash Biologically relevant physiological parameters
ndash Independent of scanner strength manufacturer and imaging routines
ndash Enables valid comparisons of serial measurements and data exchange between different imaging centres
bull Disadvantagesndash Data acquisition and analysis is more complex
ndash Lack of commercial software for analysis
ndash Models may not fit the data observed
Chen Lin PhD
DCE Perfusion of Pancreatic Tumor
Chen Lin PhD
DCE Perfusion of Pancreatic Tumor
Chen Lin PhD
PWI with Arterial Spinning Labeling
bull Tagged blood flows through vasculature and exchanges with tissue
bull Change total tissue magnetization in slice (1-2) compared to control
bull ldquoControlrdquo ndash ldquoLabeledrdquo CBF
Artery Vein
Chen Lin PhD
Labeling Techniques
bull Continuous or Steady-state ASL (CASL)
ndash Saturation (Detre 1992)
ndash Inversion (Williams 1992) with flow-driven adiabatic inversion pulse
ndash Labeling with 2nd coil
bull Pulsed ASL (uses a bolus of labeled spins) (PASL)
ndash STAR TILT PICORE FAIR hellip
bull Velocity Selective ASL
Chen Lin PhD
7142009
5
CASL with Dedicated Labeling Coil
bull Reduce SAR
bull Reduce MT effect
bull Additional hardware
Imaging Plane
Labeling Coil
Chen Lin PhD
Typical PASL Design
M0 Label Control Label ControlLabelControl
Control - Label Control - Label Control - LabelDM
CBF = 3x108 l [mlg] a [] TI1 Exp(TI2T1blood) DMM0
Image
Acquisition
Module
TI2
TI1Labeling
Control
Module
Bolus Cut-off Module
Chen Lin PhD
Chen Lin PhD
QUIPSS amp QUIPSS II
bull QUantitative Imaging of Perfusion using a Single Subtraction
bull Use saturation pulses to shave the leading or trailing edge of the bolus so the transit time is the same
Image
Acquisition
Module
TI2
TI1Labeling
Control
Module
900 900
ASL Image Acquisition Mode
bull 2D single and multiple slices
bull 3D (long acquisition time)
Chen Lin PhD
ASL Image Acquisition Methods
bull GRESE EPI (STAR + EPI Edelman 1994 FAIR + EPI Kim 1995)
bull HASTE (STAR + HAlf-fourier Single-shot Turbo spin Echo Chen 1997)
bull GRASE (FAIR + GRadient echo And Spin Echo Crelier 1999)
bull TrueFISP (FAIR + True Fast Imaging with Steady-state Precession Boss 2007)
Chen Lin PhD
PASL Issues and Optimization
bull SNR and Susceptibility artifacts
ndash Use short TE amp ETL
bull T1 Relaxation effect amp Transit Time Difference
ndash Decay of magnetization from the tagging location to imaging location
ndash The transit time of leading and trailing edge of the labeled bolus are different
bull Arterial Signal
ndash Apply a small bipolar diffusion weighting gradient b ~ 2 smm2
Chen Lin PhD
7142009
6
PASL Issues and Optimization
bull Physiological Noise
ndash Reduction with background suppression
ndash Model and correct the physiological fluctuation with statistical analysis (GLM)
bull MT effect
ndash Suppression at imaging location from off-resonance effect of labeling pulse Asymmetric with respect to frequency shift
bull Eddy Current Compensation
ndash Maintain the similar gradient waveform between tagging and control
Chen Lin PhD
MT Effect amp Labeling Schemes
bull STAR (Signal Targeting with Alternating Radio Frequency)
bull PICORE (Proximal Inversion with a Control for Off-resonance Effect) (Wong 1997)
bull TILT (Transfer Insensitive Labeling Technique) (Gobay 1999)
bull FAIR (Flow-sensitive Alternating Inversion Recovery) (Kim 1995)
Chen Lin PhD
PICORE
Tagging
Control
1800
1800
wt = wi + Dw
wc = wi + Dw
Gt = 0
Chen Lin PhD
FAIR
Tagging
Control
1800
1800
wt = wi
wc = wi
Gt = 0Chen Lin PhD
ASL Applications
bull Quantification of rest state CBF and study the perfusion changes from a disease or treatmentintervention
ndash Tumor Stroke Alzheimerrsquos Disease vascular disorder etc hellip
ndash Infant brain development (Wang Neuroimage 2008) amp Aging (Biagi JMRI 2007)
ndash Uncoupling contributions to BOLD fMRI
Chen Lin PhD
AVM
T2wDSCrMTT
ASLrCBF
DSCNEI
Chen Lin PhD
7142009
7
T2-weighted
Ischemia (RgtL)
Pre-op ASL
Hypo-perfusion (RgtL)
Post-op ASL
Bilateral increase
ASL perfusion correlated better with cognitive deficits than structural MRI
Jefferson AJNR 2006
Intracranial Stenosis
Chen Lin PhD
Du A T et al Neurology 200667125-1220
Frontotemporal Dementia (FTD) and Alzheimer Disease (AD)
FTD and AD display different spatial distributions of hypo-perfusion Chen Lin PhD
ASL Perfusion based fMRI
bull Perfusion fMRI ie Quantification of functional related dynamic CBF changes
ndashConventional stimulustasks such as sensory-motor memory speech tasks similar to those in BOLD fMRI
ndashPharmacological stimulus such caffeine or cocaine
ndashBehaviorenvironment changes such as sleep deprivation pain
Chen Lin PhD
Xu G et al Neurology 2007
CBF changes of congnitively normal (CN) amp amnestic mild cognitive impairment (aMCI) groups
A significant regional CBF percent increase occurred in the region of the right parahippocampus during the sustained memory-encoding period in the CN group but not in the aMCI group
Chen Lin PhD
ASL versus BOLD for fMRIbull Much lower SNR
1-2 signal change in ASL versus 5-10 in BOLD
bull Direct measure of CBF changesBOLD is coupled with CBF CMRO2 CBV
bull More localized and quantitative
bull Better long-term stability and reproducibilityLow frequency fMRI
bull Insensitive to magnetic susceptibility effectsUse short TE and susceptibility insensitive image acquisition
bull Less inter-subject variabilityAllows group analysis long term and multisite study
Chen Lin PhD
ASL versus DSC
bull Lower SNR and therefore typical acquired with lower resolution
bull More susceptible to physiological variation
bull Less coverage
bull Non-invasive
Chen Lin PhD
7142009
8
ASL Outside of the Brain
bull Kidney (Warmuth JMRI 2007)
bull Muscle (Frouin MRM 2006)
bull Lung (Bolar MRM 2006)
Chen Lin PhD
Getting more from Diffusion Attenuation Curve
Ln(S)
b
Perfusion
S = Sb=0 [ (1-f) endashbD + f endashb(D+D) ]
b = 50
b = 500
Chen Lin PhD
Intra Voxel Incoherence Imaging
Luciani A et al Radiology 2008 Dec249(3)891-9
DWI b=50 D
D fChen Lin PhD
Thank you
7142009
3
Tumor versus Radiation Necrosis
T2w rCBV
Chen Lin PhD
Leakage and Permeability
Chen Lin PhD
Typical DCE Perfusion Protocol
bull Spoiled 2D or 3D gradient echo (SPGR or FLASH)
bull TE = min
bull TR = min ( typically 4 ndash 10 sec)
bull FA = 30 ndash 40 deg
bull TA = several minutes
bull Contrast dose = 01 ndash 02 mmolkg
bull Injection rate 3 ndash 5 mlsec with 20 ml saline flush
bull Measure baseline T1 with different FAsChen Lin PhD
DCE-MRI Evaluation
Qualitative - shape of signal intensity (SI) data curve
Semi-quantitative - indices that describe one or more parts of SI or [Gd] curves
Upslope gradient max amplitude washout rate or area under curve at a fixed time point
True quantitative - indices from contrast medium concentration changes using pharmacokinetic modelling
Chen Lin PhD
Type I(semi-necrotic with reactive changes)
Type II(viable tumor)
Type III(rapidly proliferating
tumor edge)
(Taylor and Reddick Adv Drug Del Rev 2000)
Qualitative Evaluation of DCE-MRI time Curve
Chen Lin PhD
DCE Perfusion Modelling
( )( ) ( )transt
p ep t
trans
ep
dC tK C t k C t
dt
Kk
Ve
Chen Lin PhD
Blood plasma
Cp
Ct = Ce Ve
Ve Ce
Ktrans
Kep
Tumor Extracellular
Space
NormalExtracellular
Space
7142009
4
Quantification of Contrast Concentration
R1(t) = R1(0) + C(t) Rbull R1(t) Longitudinal relaxation rate 1T1(t) at a given time
point t can be determined from the ratio of signal intensities between T1w and PDw images SI(T1w)SI(PDw)
bull R1(0) Longitudinal relaxation rate 1T1(0) at baseline ie before contrast arrival can also be determined from SI(T1w)SI(PDw) at baseline
bull R Relaxivity of the contrast agent ie Gd-DTPA
bull C(t) Contrast concentration at a given time t can be derived
bull Ct(t) Tissue contrast concentration curve
bull Cp(t) Blood contrast concentration curve arterial input function (AIF)
Chen Lin PhD
Quantitative analysis with pharmacokinetic modelling
bull Advantagesndash Whole curve shape is analysed
ndash Biologically relevant physiological parameters
ndash Independent of scanner strength manufacturer and imaging routines
ndash Enables valid comparisons of serial measurements and data exchange between different imaging centres
bull Disadvantagesndash Data acquisition and analysis is more complex
ndash Lack of commercial software for analysis
ndash Models may not fit the data observed
Chen Lin PhD
DCE Perfusion of Pancreatic Tumor
Chen Lin PhD
DCE Perfusion of Pancreatic Tumor
Chen Lin PhD
PWI with Arterial Spinning Labeling
bull Tagged blood flows through vasculature and exchanges with tissue
bull Change total tissue magnetization in slice (1-2) compared to control
bull ldquoControlrdquo ndash ldquoLabeledrdquo CBF
Artery Vein
Chen Lin PhD
Labeling Techniques
bull Continuous or Steady-state ASL (CASL)
ndash Saturation (Detre 1992)
ndash Inversion (Williams 1992) with flow-driven adiabatic inversion pulse
ndash Labeling with 2nd coil
bull Pulsed ASL (uses a bolus of labeled spins) (PASL)
ndash STAR TILT PICORE FAIR hellip
bull Velocity Selective ASL
Chen Lin PhD
7142009
5
CASL with Dedicated Labeling Coil
bull Reduce SAR
bull Reduce MT effect
bull Additional hardware
Imaging Plane
Labeling Coil
Chen Lin PhD
Typical PASL Design
M0 Label Control Label ControlLabelControl
Control - Label Control - Label Control - LabelDM
CBF = 3x108 l [mlg] a [] TI1 Exp(TI2T1blood) DMM0
Image
Acquisition
Module
TI2
TI1Labeling
Control
Module
Bolus Cut-off Module
Chen Lin PhD
Chen Lin PhD
QUIPSS amp QUIPSS II
bull QUantitative Imaging of Perfusion using a Single Subtraction
bull Use saturation pulses to shave the leading or trailing edge of the bolus so the transit time is the same
Image
Acquisition
Module
TI2
TI1Labeling
Control
Module
900 900
ASL Image Acquisition Mode
bull 2D single and multiple slices
bull 3D (long acquisition time)
Chen Lin PhD
ASL Image Acquisition Methods
bull GRESE EPI (STAR + EPI Edelman 1994 FAIR + EPI Kim 1995)
bull HASTE (STAR + HAlf-fourier Single-shot Turbo spin Echo Chen 1997)
bull GRASE (FAIR + GRadient echo And Spin Echo Crelier 1999)
bull TrueFISP (FAIR + True Fast Imaging with Steady-state Precession Boss 2007)
Chen Lin PhD
PASL Issues and Optimization
bull SNR and Susceptibility artifacts
ndash Use short TE amp ETL
bull T1 Relaxation effect amp Transit Time Difference
ndash Decay of magnetization from the tagging location to imaging location
ndash The transit time of leading and trailing edge of the labeled bolus are different
bull Arterial Signal
ndash Apply a small bipolar diffusion weighting gradient b ~ 2 smm2
Chen Lin PhD
7142009
6
PASL Issues and Optimization
bull Physiological Noise
ndash Reduction with background suppression
ndash Model and correct the physiological fluctuation with statistical analysis (GLM)
bull MT effect
ndash Suppression at imaging location from off-resonance effect of labeling pulse Asymmetric with respect to frequency shift
bull Eddy Current Compensation
ndash Maintain the similar gradient waveform between tagging and control
Chen Lin PhD
MT Effect amp Labeling Schemes
bull STAR (Signal Targeting with Alternating Radio Frequency)
bull PICORE (Proximal Inversion with a Control for Off-resonance Effect) (Wong 1997)
bull TILT (Transfer Insensitive Labeling Technique) (Gobay 1999)
bull FAIR (Flow-sensitive Alternating Inversion Recovery) (Kim 1995)
Chen Lin PhD
PICORE
Tagging
Control
1800
1800
wt = wi + Dw
wc = wi + Dw
Gt = 0
Chen Lin PhD
FAIR
Tagging
Control
1800
1800
wt = wi
wc = wi
Gt = 0Chen Lin PhD
ASL Applications
bull Quantification of rest state CBF and study the perfusion changes from a disease or treatmentintervention
ndash Tumor Stroke Alzheimerrsquos Disease vascular disorder etc hellip
ndash Infant brain development (Wang Neuroimage 2008) amp Aging (Biagi JMRI 2007)
ndash Uncoupling contributions to BOLD fMRI
Chen Lin PhD
AVM
T2wDSCrMTT
ASLrCBF
DSCNEI
Chen Lin PhD
7142009
7
T2-weighted
Ischemia (RgtL)
Pre-op ASL
Hypo-perfusion (RgtL)
Post-op ASL
Bilateral increase
ASL perfusion correlated better with cognitive deficits than structural MRI
Jefferson AJNR 2006
Intracranial Stenosis
Chen Lin PhD
Du A T et al Neurology 200667125-1220
Frontotemporal Dementia (FTD) and Alzheimer Disease (AD)
FTD and AD display different spatial distributions of hypo-perfusion Chen Lin PhD
ASL Perfusion based fMRI
bull Perfusion fMRI ie Quantification of functional related dynamic CBF changes
ndashConventional stimulustasks such as sensory-motor memory speech tasks similar to those in BOLD fMRI
ndashPharmacological stimulus such caffeine or cocaine
ndashBehaviorenvironment changes such as sleep deprivation pain
Chen Lin PhD
Xu G et al Neurology 2007
CBF changes of congnitively normal (CN) amp amnestic mild cognitive impairment (aMCI) groups
A significant regional CBF percent increase occurred in the region of the right parahippocampus during the sustained memory-encoding period in the CN group but not in the aMCI group
Chen Lin PhD
ASL versus BOLD for fMRIbull Much lower SNR
1-2 signal change in ASL versus 5-10 in BOLD
bull Direct measure of CBF changesBOLD is coupled with CBF CMRO2 CBV
bull More localized and quantitative
bull Better long-term stability and reproducibilityLow frequency fMRI
bull Insensitive to magnetic susceptibility effectsUse short TE and susceptibility insensitive image acquisition
bull Less inter-subject variabilityAllows group analysis long term and multisite study
Chen Lin PhD
ASL versus DSC
bull Lower SNR and therefore typical acquired with lower resolution
bull More susceptible to physiological variation
bull Less coverage
bull Non-invasive
Chen Lin PhD
7142009
8
ASL Outside of the Brain
bull Kidney (Warmuth JMRI 2007)
bull Muscle (Frouin MRM 2006)
bull Lung (Bolar MRM 2006)
Chen Lin PhD
Getting more from Diffusion Attenuation Curve
Ln(S)
b
Perfusion
S = Sb=0 [ (1-f) endashbD + f endashb(D+D) ]
b = 50
b = 500
Chen Lin PhD
Intra Voxel Incoherence Imaging
Luciani A et al Radiology 2008 Dec249(3)891-9
DWI b=50 D
D fChen Lin PhD
Thank you
7142009
4
Quantification of Contrast Concentration
R1(t) = R1(0) + C(t) Rbull R1(t) Longitudinal relaxation rate 1T1(t) at a given time
point t can be determined from the ratio of signal intensities between T1w and PDw images SI(T1w)SI(PDw)
bull R1(0) Longitudinal relaxation rate 1T1(0) at baseline ie before contrast arrival can also be determined from SI(T1w)SI(PDw) at baseline
bull R Relaxivity of the contrast agent ie Gd-DTPA
bull C(t) Contrast concentration at a given time t can be derived
bull Ct(t) Tissue contrast concentration curve
bull Cp(t) Blood contrast concentration curve arterial input function (AIF)
Chen Lin PhD
Quantitative analysis with pharmacokinetic modelling
bull Advantagesndash Whole curve shape is analysed
ndash Biologically relevant physiological parameters
ndash Independent of scanner strength manufacturer and imaging routines
ndash Enables valid comparisons of serial measurements and data exchange between different imaging centres
bull Disadvantagesndash Data acquisition and analysis is more complex
ndash Lack of commercial software for analysis
ndash Models may not fit the data observed
Chen Lin PhD
DCE Perfusion of Pancreatic Tumor
Chen Lin PhD
DCE Perfusion of Pancreatic Tumor
Chen Lin PhD
PWI with Arterial Spinning Labeling
bull Tagged blood flows through vasculature and exchanges with tissue
bull Change total tissue magnetization in slice (1-2) compared to control
bull ldquoControlrdquo ndash ldquoLabeledrdquo CBF
Artery Vein
Chen Lin PhD
Labeling Techniques
bull Continuous or Steady-state ASL (CASL)
ndash Saturation (Detre 1992)
ndash Inversion (Williams 1992) with flow-driven adiabatic inversion pulse
ndash Labeling with 2nd coil
bull Pulsed ASL (uses a bolus of labeled spins) (PASL)
ndash STAR TILT PICORE FAIR hellip
bull Velocity Selective ASL
Chen Lin PhD
7142009
5
CASL with Dedicated Labeling Coil
bull Reduce SAR
bull Reduce MT effect
bull Additional hardware
Imaging Plane
Labeling Coil
Chen Lin PhD
Typical PASL Design
M0 Label Control Label ControlLabelControl
Control - Label Control - Label Control - LabelDM
CBF = 3x108 l [mlg] a [] TI1 Exp(TI2T1blood) DMM0
Image
Acquisition
Module
TI2
TI1Labeling
Control
Module
Bolus Cut-off Module
Chen Lin PhD
Chen Lin PhD
QUIPSS amp QUIPSS II
bull QUantitative Imaging of Perfusion using a Single Subtraction
bull Use saturation pulses to shave the leading or trailing edge of the bolus so the transit time is the same
Image
Acquisition
Module
TI2
TI1Labeling
Control
Module
900 900
ASL Image Acquisition Mode
bull 2D single and multiple slices
bull 3D (long acquisition time)
Chen Lin PhD
ASL Image Acquisition Methods
bull GRESE EPI (STAR + EPI Edelman 1994 FAIR + EPI Kim 1995)
bull HASTE (STAR + HAlf-fourier Single-shot Turbo spin Echo Chen 1997)
bull GRASE (FAIR + GRadient echo And Spin Echo Crelier 1999)
bull TrueFISP (FAIR + True Fast Imaging with Steady-state Precession Boss 2007)
Chen Lin PhD
PASL Issues and Optimization
bull SNR and Susceptibility artifacts
ndash Use short TE amp ETL
bull T1 Relaxation effect amp Transit Time Difference
ndash Decay of magnetization from the tagging location to imaging location
ndash The transit time of leading and trailing edge of the labeled bolus are different
bull Arterial Signal
ndash Apply a small bipolar diffusion weighting gradient b ~ 2 smm2
Chen Lin PhD
7142009
6
PASL Issues and Optimization
bull Physiological Noise
ndash Reduction with background suppression
ndash Model and correct the physiological fluctuation with statistical analysis (GLM)
bull MT effect
ndash Suppression at imaging location from off-resonance effect of labeling pulse Asymmetric with respect to frequency shift
bull Eddy Current Compensation
ndash Maintain the similar gradient waveform between tagging and control
Chen Lin PhD
MT Effect amp Labeling Schemes
bull STAR (Signal Targeting with Alternating Radio Frequency)
bull PICORE (Proximal Inversion with a Control for Off-resonance Effect) (Wong 1997)
bull TILT (Transfer Insensitive Labeling Technique) (Gobay 1999)
bull FAIR (Flow-sensitive Alternating Inversion Recovery) (Kim 1995)
Chen Lin PhD
PICORE
Tagging
Control
1800
1800
wt = wi + Dw
wc = wi + Dw
Gt = 0
Chen Lin PhD
FAIR
Tagging
Control
1800
1800
wt = wi
wc = wi
Gt = 0Chen Lin PhD
ASL Applications
bull Quantification of rest state CBF and study the perfusion changes from a disease or treatmentintervention
ndash Tumor Stroke Alzheimerrsquos Disease vascular disorder etc hellip
ndash Infant brain development (Wang Neuroimage 2008) amp Aging (Biagi JMRI 2007)
ndash Uncoupling contributions to BOLD fMRI
Chen Lin PhD
AVM
T2wDSCrMTT
ASLrCBF
DSCNEI
Chen Lin PhD
7142009
7
T2-weighted
Ischemia (RgtL)
Pre-op ASL
Hypo-perfusion (RgtL)
Post-op ASL
Bilateral increase
ASL perfusion correlated better with cognitive deficits than structural MRI
Jefferson AJNR 2006
Intracranial Stenosis
Chen Lin PhD
Du A T et al Neurology 200667125-1220
Frontotemporal Dementia (FTD) and Alzheimer Disease (AD)
FTD and AD display different spatial distributions of hypo-perfusion Chen Lin PhD
ASL Perfusion based fMRI
bull Perfusion fMRI ie Quantification of functional related dynamic CBF changes
ndashConventional stimulustasks such as sensory-motor memory speech tasks similar to those in BOLD fMRI
ndashPharmacological stimulus such caffeine or cocaine
ndashBehaviorenvironment changes such as sleep deprivation pain
Chen Lin PhD
Xu G et al Neurology 2007
CBF changes of congnitively normal (CN) amp amnestic mild cognitive impairment (aMCI) groups
A significant regional CBF percent increase occurred in the region of the right parahippocampus during the sustained memory-encoding period in the CN group but not in the aMCI group
Chen Lin PhD
ASL versus BOLD for fMRIbull Much lower SNR
1-2 signal change in ASL versus 5-10 in BOLD
bull Direct measure of CBF changesBOLD is coupled with CBF CMRO2 CBV
bull More localized and quantitative
bull Better long-term stability and reproducibilityLow frequency fMRI
bull Insensitive to magnetic susceptibility effectsUse short TE and susceptibility insensitive image acquisition
bull Less inter-subject variabilityAllows group analysis long term and multisite study
Chen Lin PhD
ASL versus DSC
bull Lower SNR and therefore typical acquired with lower resolution
bull More susceptible to physiological variation
bull Less coverage
bull Non-invasive
Chen Lin PhD
7142009
8
ASL Outside of the Brain
bull Kidney (Warmuth JMRI 2007)
bull Muscle (Frouin MRM 2006)
bull Lung (Bolar MRM 2006)
Chen Lin PhD
Getting more from Diffusion Attenuation Curve
Ln(S)
b
Perfusion
S = Sb=0 [ (1-f) endashbD + f endashb(D+D) ]
b = 50
b = 500
Chen Lin PhD
Intra Voxel Incoherence Imaging
Luciani A et al Radiology 2008 Dec249(3)891-9
DWI b=50 D
D fChen Lin PhD
Thank you
7142009
5
CASL with Dedicated Labeling Coil
bull Reduce SAR
bull Reduce MT effect
bull Additional hardware
Imaging Plane
Labeling Coil
Chen Lin PhD
Typical PASL Design
M0 Label Control Label ControlLabelControl
Control - Label Control - Label Control - LabelDM
CBF = 3x108 l [mlg] a [] TI1 Exp(TI2T1blood) DMM0
Image
Acquisition
Module
TI2
TI1Labeling
Control
Module
Bolus Cut-off Module
Chen Lin PhD
Chen Lin PhD
QUIPSS amp QUIPSS II
bull QUantitative Imaging of Perfusion using a Single Subtraction
bull Use saturation pulses to shave the leading or trailing edge of the bolus so the transit time is the same
Image
Acquisition
Module
TI2
TI1Labeling
Control
Module
900 900
ASL Image Acquisition Mode
bull 2D single and multiple slices
bull 3D (long acquisition time)
Chen Lin PhD
ASL Image Acquisition Methods
bull GRESE EPI (STAR + EPI Edelman 1994 FAIR + EPI Kim 1995)
bull HASTE (STAR + HAlf-fourier Single-shot Turbo spin Echo Chen 1997)
bull GRASE (FAIR + GRadient echo And Spin Echo Crelier 1999)
bull TrueFISP (FAIR + True Fast Imaging with Steady-state Precession Boss 2007)
Chen Lin PhD
PASL Issues and Optimization
bull SNR and Susceptibility artifacts
ndash Use short TE amp ETL
bull T1 Relaxation effect amp Transit Time Difference
ndash Decay of magnetization from the tagging location to imaging location
ndash The transit time of leading and trailing edge of the labeled bolus are different
bull Arterial Signal
ndash Apply a small bipolar diffusion weighting gradient b ~ 2 smm2
Chen Lin PhD
7142009
6
PASL Issues and Optimization
bull Physiological Noise
ndash Reduction with background suppression
ndash Model and correct the physiological fluctuation with statistical analysis (GLM)
bull MT effect
ndash Suppression at imaging location from off-resonance effect of labeling pulse Asymmetric with respect to frequency shift
bull Eddy Current Compensation
ndash Maintain the similar gradient waveform between tagging and control
Chen Lin PhD
MT Effect amp Labeling Schemes
bull STAR (Signal Targeting with Alternating Radio Frequency)
bull PICORE (Proximal Inversion with a Control for Off-resonance Effect) (Wong 1997)
bull TILT (Transfer Insensitive Labeling Technique) (Gobay 1999)
bull FAIR (Flow-sensitive Alternating Inversion Recovery) (Kim 1995)
Chen Lin PhD
PICORE
Tagging
Control
1800
1800
wt = wi + Dw
wc = wi + Dw
Gt = 0
Chen Lin PhD
FAIR
Tagging
Control
1800
1800
wt = wi
wc = wi
Gt = 0Chen Lin PhD
ASL Applications
bull Quantification of rest state CBF and study the perfusion changes from a disease or treatmentintervention
ndash Tumor Stroke Alzheimerrsquos Disease vascular disorder etc hellip
ndash Infant brain development (Wang Neuroimage 2008) amp Aging (Biagi JMRI 2007)
ndash Uncoupling contributions to BOLD fMRI
Chen Lin PhD
AVM
T2wDSCrMTT
ASLrCBF
DSCNEI
Chen Lin PhD
7142009
7
T2-weighted
Ischemia (RgtL)
Pre-op ASL
Hypo-perfusion (RgtL)
Post-op ASL
Bilateral increase
ASL perfusion correlated better with cognitive deficits than structural MRI
Jefferson AJNR 2006
Intracranial Stenosis
Chen Lin PhD
Du A T et al Neurology 200667125-1220
Frontotemporal Dementia (FTD) and Alzheimer Disease (AD)
FTD and AD display different spatial distributions of hypo-perfusion Chen Lin PhD
ASL Perfusion based fMRI
bull Perfusion fMRI ie Quantification of functional related dynamic CBF changes
ndashConventional stimulustasks such as sensory-motor memory speech tasks similar to those in BOLD fMRI
ndashPharmacological stimulus such caffeine or cocaine
ndashBehaviorenvironment changes such as sleep deprivation pain
Chen Lin PhD
Xu G et al Neurology 2007
CBF changes of congnitively normal (CN) amp amnestic mild cognitive impairment (aMCI) groups
A significant regional CBF percent increase occurred in the region of the right parahippocampus during the sustained memory-encoding period in the CN group but not in the aMCI group
Chen Lin PhD
ASL versus BOLD for fMRIbull Much lower SNR
1-2 signal change in ASL versus 5-10 in BOLD
bull Direct measure of CBF changesBOLD is coupled with CBF CMRO2 CBV
bull More localized and quantitative
bull Better long-term stability and reproducibilityLow frequency fMRI
bull Insensitive to magnetic susceptibility effectsUse short TE and susceptibility insensitive image acquisition
bull Less inter-subject variabilityAllows group analysis long term and multisite study
Chen Lin PhD
ASL versus DSC
bull Lower SNR and therefore typical acquired with lower resolution
bull More susceptible to physiological variation
bull Less coverage
bull Non-invasive
Chen Lin PhD
7142009
8
ASL Outside of the Brain
bull Kidney (Warmuth JMRI 2007)
bull Muscle (Frouin MRM 2006)
bull Lung (Bolar MRM 2006)
Chen Lin PhD
Getting more from Diffusion Attenuation Curve
Ln(S)
b
Perfusion
S = Sb=0 [ (1-f) endashbD + f endashb(D+D) ]
b = 50
b = 500
Chen Lin PhD
Intra Voxel Incoherence Imaging
Luciani A et al Radiology 2008 Dec249(3)891-9
DWI b=50 D
D fChen Lin PhD
Thank you
7142009
6
PASL Issues and Optimization
bull Physiological Noise
ndash Reduction with background suppression
ndash Model and correct the physiological fluctuation with statistical analysis (GLM)
bull MT effect
ndash Suppression at imaging location from off-resonance effect of labeling pulse Asymmetric with respect to frequency shift
bull Eddy Current Compensation
ndash Maintain the similar gradient waveform between tagging and control
Chen Lin PhD
MT Effect amp Labeling Schemes
bull STAR (Signal Targeting with Alternating Radio Frequency)
bull PICORE (Proximal Inversion with a Control for Off-resonance Effect) (Wong 1997)
bull TILT (Transfer Insensitive Labeling Technique) (Gobay 1999)
bull FAIR (Flow-sensitive Alternating Inversion Recovery) (Kim 1995)
Chen Lin PhD
PICORE
Tagging
Control
1800
1800
wt = wi + Dw
wc = wi + Dw
Gt = 0
Chen Lin PhD
FAIR
Tagging
Control
1800
1800
wt = wi
wc = wi
Gt = 0Chen Lin PhD
ASL Applications
bull Quantification of rest state CBF and study the perfusion changes from a disease or treatmentintervention
ndash Tumor Stroke Alzheimerrsquos Disease vascular disorder etc hellip
ndash Infant brain development (Wang Neuroimage 2008) amp Aging (Biagi JMRI 2007)
ndash Uncoupling contributions to BOLD fMRI
Chen Lin PhD
AVM
T2wDSCrMTT
ASLrCBF
DSCNEI
Chen Lin PhD
7142009
7
T2-weighted
Ischemia (RgtL)
Pre-op ASL
Hypo-perfusion (RgtL)
Post-op ASL
Bilateral increase
ASL perfusion correlated better with cognitive deficits than structural MRI
Jefferson AJNR 2006
Intracranial Stenosis
Chen Lin PhD
Du A T et al Neurology 200667125-1220
Frontotemporal Dementia (FTD) and Alzheimer Disease (AD)
FTD and AD display different spatial distributions of hypo-perfusion Chen Lin PhD
ASL Perfusion based fMRI
bull Perfusion fMRI ie Quantification of functional related dynamic CBF changes
ndashConventional stimulustasks such as sensory-motor memory speech tasks similar to those in BOLD fMRI
ndashPharmacological stimulus such caffeine or cocaine
ndashBehaviorenvironment changes such as sleep deprivation pain
Chen Lin PhD
Xu G et al Neurology 2007
CBF changes of congnitively normal (CN) amp amnestic mild cognitive impairment (aMCI) groups
A significant regional CBF percent increase occurred in the region of the right parahippocampus during the sustained memory-encoding period in the CN group but not in the aMCI group
Chen Lin PhD
ASL versus BOLD for fMRIbull Much lower SNR
1-2 signal change in ASL versus 5-10 in BOLD
bull Direct measure of CBF changesBOLD is coupled with CBF CMRO2 CBV
bull More localized and quantitative
bull Better long-term stability and reproducibilityLow frequency fMRI
bull Insensitive to magnetic susceptibility effectsUse short TE and susceptibility insensitive image acquisition
bull Less inter-subject variabilityAllows group analysis long term and multisite study
Chen Lin PhD
ASL versus DSC
bull Lower SNR and therefore typical acquired with lower resolution
bull More susceptible to physiological variation
bull Less coverage
bull Non-invasive
Chen Lin PhD
7142009
8
ASL Outside of the Brain
bull Kidney (Warmuth JMRI 2007)
bull Muscle (Frouin MRM 2006)
bull Lung (Bolar MRM 2006)
Chen Lin PhD
Getting more from Diffusion Attenuation Curve
Ln(S)
b
Perfusion
S = Sb=0 [ (1-f) endashbD + f endashb(D+D) ]
b = 50
b = 500
Chen Lin PhD
Intra Voxel Incoherence Imaging
Luciani A et al Radiology 2008 Dec249(3)891-9
DWI b=50 D
D fChen Lin PhD
Thank you
7142009
7
T2-weighted
Ischemia (RgtL)
Pre-op ASL
Hypo-perfusion (RgtL)
Post-op ASL
Bilateral increase
ASL perfusion correlated better with cognitive deficits than structural MRI
Jefferson AJNR 2006
Intracranial Stenosis
Chen Lin PhD
Du A T et al Neurology 200667125-1220
Frontotemporal Dementia (FTD) and Alzheimer Disease (AD)
FTD and AD display different spatial distributions of hypo-perfusion Chen Lin PhD
ASL Perfusion based fMRI
bull Perfusion fMRI ie Quantification of functional related dynamic CBF changes
ndashConventional stimulustasks such as sensory-motor memory speech tasks similar to those in BOLD fMRI
ndashPharmacological stimulus such caffeine or cocaine
ndashBehaviorenvironment changes such as sleep deprivation pain
Chen Lin PhD
Xu G et al Neurology 2007
CBF changes of congnitively normal (CN) amp amnestic mild cognitive impairment (aMCI) groups
A significant regional CBF percent increase occurred in the region of the right parahippocampus during the sustained memory-encoding period in the CN group but not in the aMCI group
Chen Lin PhD
ASL versus BOLD for fMRIbull Much lower SNR
1-2 signal change in ASL versus 5-10 in BOLD
bull Direct measure of CBF changesBOLD is coupled with CBF CMRO2 CBV
bull More localized and quantitative
bull Better long-term stability and reproducibilityLow frequency fMRI
bull Insensitive to magnetic susceptibility effectsUse short TE and susceptibility insensitive image acquisition
bull Less inter-subject variabilityAllows group analysis long term and multisite study
Chen Lin PhD
ASL versus DSC
bull Lower SNR and therefore typical acquired with lower resolution
bull More susceptible to physiological variation
bull Less coverage
bull Non-invasive
Chen Lin PhD
7142009
8
ASL Outside of the Brain
bull Kidney (Warmuth JMRI 2007)
bull Muscle (Frouin MRM 2006)
bull Lung (Bolar MRM 2006)
Chen Lin PhD
Getting more from Diffusion Attenuation Curve
Ln(S)
b
Perfusion
S = Sb=0 [ (1-f) endashbD + f endashb(D+D) ]
b = 50
b = 500
Chen Lin PhD
Intra Voxel Incoherence Imaging
Luciani A et al Radiology 2008 Dec249(3)891-9
DWI b=50 D
D fChen Lin PhD
Thank you
7142009
8
ASL Outside of the Brain
bull Kidney (Warmuth JMRI 2007)
bull Muscle (Frouin MRM 2006)
bull Lung (Bolar MRM 2006)
Chen Lin PhD
Getting more from Diffusion Attenuation Curve
Ln(S)
b
Perfusion
S = Sb=0 [ (1-f) endashbD + f endashb(D+D) ]
b = 50
b = 500
Chen Lin PhD
Intra Voxel Incoherence Imaging
Luciani A et al Radiology 2008 Dec249(3)891-9
DWI b=50 D
D fChen Lin PhD
Thank you
