mri of shoulder injury

MRI OF SHOULDER JOINT

Dr Krishna Kiran MD.DNB.FRCR RadiologistCalicut

This presentation is intended for medical and

allied professionals.

What is T1,T2.. And many other fancy names used in MRI..??

T2 T1 FAT

SUPPRESSED

STIR/PDFS

Common sequences in MRI shoulder

How do you do shoulder MRI..

Shoulder MRI is done in a plane parallel to supraspinatus.

Generally sequences obtained are

Coronal plane T1, T2, Fatsuppressed (STIR or PDFS)

Axial - T1, fatsuppressed

Sagittal - T2 and fat suppressed.

Key section in shoulder coronal image in the middle third

Anterior coronal section

Posterior coronal section shoulder

Sagittal section

Axial anatomy

After review of anatomy , Let us proceed to our case.

CASE 1?ROTATOR CUFF TEAR

Full thickness tear supraspinatus tendon except fibers in anterior third

Complete tears of supraspinatus tendon are accompanied by muscle atrophy and fatty infiltration.

These are important negative prognostic factors for tendon repair and shoulder arthroplasty.

Muscle thickness using Fat occupancy ratioand fatty infiltration of muscle can be assessed on MRI.

Fat occupancy ratio

Reduced fat occupancy Normal fat occupancy

Fatty infiltration

supraspinatus

Normal supraspinatus

Case 2

? Rotator cuff tear

Avulsion Fracture greater tuberosity of humerus

Case 3

?RCT

Rimrent or PASTA tear

Rimrent or PASTA tear

A partial tear that extends to articular surface does not extent to bursal surface.

Case 4

Recurrent Dislocation shoulder

Anterior middle posterior

Coronal sections

Posterior sections of shoulder

Hill Sach Lesion

Anterior labral tear

Normal anterior labrum for comparison

Labral clockClockwise approach to

labrum is the easiest way

to diagnose labral tears

and differentiate them

from normal variants.

ABER view

Abduction external rotation view of shoulder is utilized to detect

subtle soft tissue pathology of anteroinferior labrum and rotator

cuff.

Types of anteroinferior labraltears.

Bankart

lesion

Perthe

lesion

ALPSA

lesion

Case 5

Shoulder pain and limitation of movement.

Anterior middle

posterior

Anterior capsule thickening indicative of adhesive capsulitis.

Normal for comparison

Case 6

Shoulder pain on overhead hand

movement

Anterior middle

posterior

Anterior middle

posterior

Supraspinatus tendonitis / tendinopathy

MRI shows tendon enlargement and mild intratendinous

hyperintense signal.

Case 7

Suspected scapula fracture

3D CT is done to assess

scapula and adjacent

injuries.

Case 8

An athlete complains of pain on throwing and overhead movement of arm.

MR Arthrogram

Hyperintense signal within labrum extending

posteriorly. Indicative of SLAP lesion. (Superior Labral

anteroposterior tear)

Labrum shows several anatomical variations. Conventional MRI is not

accurate in diagnosing labral tears (40-70% sensitivity and specificity) MR

Arthrography is more accurate (90-95% sensitivity and specificity)

CASE 1O

History of Trauma

AP shoulder

Y view or scapula lateral

Posterior dislocation

Internally rotated humerus giving light bulb appearance. Y view showing

posterior dislocation.

Other views of shoulder

Outlet or Neer`s view

Other views

Axillary view

What about ultrasound..?

Useful tool in

•Rotator cuff tendinopathy or tear.

•Calcific tendonitis.

•Subacromial bursal effusion.

Limitations

•Many parts of joint can not be

assessed.

•Operator dependent

Coronal STIR Coronal T2

Some sequences reveal mild bright signal / hyperintensity within

substance of supraspinatus. If seen without tendon enlargement is

indicative of artifact called magic angle phenomenon. Is said to be due

to orientation of collagen fibers.

What is magic angle phenomenon..?

What is difference between low strength and 1.5T magnet..?

0.2T

1.5 T

How accurate are shoulder MRI reports..? 15-20% of asymptomatic adults on shoulder MRI

revealed rotator cuff tears.

A shoulder surgeon with correlation between arthroscopy and MRI may be able to correlate image findings better.

In doubtful cases it is better to mutually discuss and proceed.

Sher et al JBJS 1995

What are types of acromion..?

Type 2 and 3 are

associated with

shoulder impingement

QUIZ

Shoulder , arm pain after suddenly lifting heavy weight

SLAP tear

extending to

biceps anchor

Take home points..

Shoulder is a complex joint , imaging also tends to be complex and prone for errors.

When in doubt discuss and proceed.

Signal within tendon may not be significant , remember magic angle ..!!