TEAR:
US:
Massive tear:
Bald humeral head
Full thickness tear:
Usually at anterior edge at insertion; some lie more posteriorly or proximally
Loss of convexity
Deltoid sitting on the humerus
Compressability of deltoid against humerus
Visulaization of cartilage - naked cartilage sign
Heterogenously hypoechoic echotexture with bursal surface fluid
Severe distortion of architexture
Partial tear:
Articular surface more common than bursal surface
Hypoechoic focal defect at undersurface, bursal surface or intrasubstance
Linear echogenic focus within the substance
Thinning of supraspinatus
Loss of convexity
Leading edge tear:
Gap between supraspinatus and biceps
Acute tear:
Clear discontinuity of tendon with obvious gap filled with fluid
Chronic tear:
Tears are more subtle; loss of normal convexity of superior surface of tendon with deltoid sagging into gap
MRI:
Massive tear:
Retracted end of tendon lies medially under acromium
Full thickness tear:
High signal on T2 extending from superior to inferior border of tendon
Tendon avulsion and retraction
Best appreciated on T2
May be filkled with hypertrophic synovium, granulation ot fibrotic tisuue, resulting in intermediate or low signal in all sequences
Partial thickness tear:
Focal high signal that contacts only one surface
Interruption of deep fibres suggests undersurface tear
Interruption of superficial fibres suggests bursal surface tear
Chronic tear: atrophy of supraspinatus muscle
DEGENERATION:
US:
Focal hypoechogenicity within tendon Fluid in subacromial bursa Swollen tendon in acute phase Difficult to differentiate degeneration from partial tears During arm abduction, bunching up of subacromial bursa against coracoacromial ligament and the acromium
MRI:
More sensitive than US Diffuse or patchy high signal within substance of tendon Irregularity in greater tuberosity Spurs in under surface of acromium Difficult to differentiate degeneration from partial tears
References:
1. Ostlere S. Imaging the shoulder.Imaging 15:162-173 (2003)
2. Seibold C et al. Rotator Cuff: Evaluation with US and MR Imaging. Radiographics. 1999;19:685-705
Image Gallary:
Image 1: Calcific tendinosis of supraspinatus AP view
Full thickness tear: Flat supraspinatus suggests underlying full thickness tear: Commonly associated with subacromial-subdeltoid bursitis:
