Rotator Cuff Tear on MRI: Imaging Findings

MRI is the gold standard for evaluating rotator cuff tears. Coronal-oblique sequences best demonstrate the supraspinatus tendon, while axial T2-FS images reveal the subscapularis and infraspinatus. Full-thickness tears appear as fluid signal completely traversing the tendon on T2-weighted fat-suppressed images. Partial-thickness tears show focal high signal within the tendon substance or at its articular or bursal surface. MR arthrogram with intra-articular gadolinium improves sensitivity for partial-thickness articular-surface tears, as contrast tracks into the tendon defect.

A partial-thickness tear involves only part of the tendon thickness and does not communicate between the glenohumeral joint and the subacromial bursa. Full-thickness tears extend entirely through the tendon, allowing fluid and, on MR arthrogram, contrast to pass from the joint into the subacromial-subdeltoid bursa. Full-thickness tears are further classified by size: small (<1 cm), medium (1–3 cm), large (3–5 cm), and massive (>5 cm or involving multiple tendons). The supraspinatus is the most commonly torn tendon, typically at its critical zone 1 cm from the footprint.

Surgical repair is typically recommended for acute full-thickness tears in active individuals, tears associated with significant weakness or functional loss, and partial tears involving more than 50% of tendon thickness. Younger patients and those with traumatic tears benefit most from early repair, as chronic retraction and fatty infiltration of the supraspinatus and infraspinatus muscles worsen outcomes over time. Arthroscopic techniques allow repair of the torn tendon back to its footprint with suture anchors. Conservative management with physical therapy, corticosteroid injections, and activity modification is first-line for degenerative partial tears in older, lower-demand patients.