By Dr.karna venkateswara reddy

MRI In Orthopaedics

INTRODUCTION

MRI is a noninvasive procedure and allows to visualise the structures.

Felix bloch and EM purcell discovered the physical phenomenon of MRI

in 1946.

Medical application – odebald and lindstorm in 1955

Paul C Lauterbur and Peter Mansfield were awarded nobel prize in 2003

for introducing three dimensional MRI.

The system includes

MECHANISM

T1 and T2 weighed images

• The T1 relaxation time ( longitudinal relaxation time)

- used to describe the return of protons back to equilibrium after application and removal of the rf pulse.

-- Provide good anatomic detail

• T2 relaxation time (transverse relaxation time)

- used to describe the associated loss of coherence or phase between individual protons immediately after the application of the rf pulse.

- used for evaluation of pathologic processes.

T1 weighted images are : Sharp

Well defined

Anatomic imaging

Fat-bright; fluid-dark

T2 weighted imaging is traditionally known as

“PATHOLOGICAL IMAGING”

They are sensitive for detecting edema.

On traditional spin echo T2 imaging

fat-dark; fluid-bright

Intensity of MR signals depends upon

the Concentration

of H+ nuclei

Spinning character

Relaxation rates

following excitation

USES OF MRI IN ORTHOPAEDICS

MRI SPINE: Axial/Saggital/Coronal

• INTER VERTEBRAL DISC: Bulge, protrusion, extrusion,

sequestration

SPINAL TUMORS:

Excellent delineation of vertebral body marrow allows detection of

primary and metastatic diseases on T1 weighed sequences.

SPINAL TRAUMA: It helps in suspected spinal cord injury, epidural hematoma, disc herniation.

MRI KNEEBest evaluated in saggital images.

Meniscal injuries

ACL and PCL injuries

Collateral ligament injuries

• OTHER USES: Osteonecrosis, synovial pathological conditions,

• occult fractures, tears of patellar and quadriceps tendon.

NORMAL ACL ACL TEAR

NORMAL PCL PCL TEAR

MENISCAL CYST

MRI HIP : Osteonecrosis

Occult femoral fractures

Labral tears

On T1 weighing images a geographical region of decreased marrow

segment within the normal bright fat of femoral head.

T2 weighed reveals DOUBLE LINE SIGN

MRI SHOULDER : Coronal oblique/axial/

Saggital oblique

Indicated in : Rotator cuff tears

Impingement syndromes

Labral tears

Occult fractures

Osteonecrosis

Long head of biceps pathology

ROTATOR CUFF TEAR SLAP LESION

MRI FOOT AND ANKLE : Detects tendon injuries,

bone marrow disorders, fractures, osteonecrosis,

osteomyelitis, ligament injuries.

MRI OF WRIST AND HAND : To detect carpal ligament disruption , avascular necrosis of lunate.

MRI OF ELBOW : To asses biceps and triceps tendons, collateral

ligaments injury.

TUMOR IMAGING

MRI should only be done after x-ray.

• Imaging should be performed in atleast 2 planes one of which should be

axial.

• T1 weighed images are useful in

identifying areas of marrow replacement

or edema.

• T2 weighed sequences delineates soft

tissue extension

ADVANTAGES DISADVANTAGES

No ionizing radiation Takes longer time for sequences

Better soft tissue contrast than CT More expensive and claustrophobic

Non invasive, specific, accurate. Dynamic testing is not possible

Gantry narrower than in CT

Gadalonium contrast cant be used in pregnant women

noisy

Contraindications

• Intra cerebral aneurysm clips.

• Internal hearing aids.

• Middle ear prosthesis.

• Cardiac pace makers.

• Implants.

• 1st trimester of pregnancy.

• Metallic orbital foreign bodies.

Thank you...