How to Read an Elbow MRI: A Patient's Guide

Standard MRI Sequences

• T1-weighted images show excellent anatomical detail with fat appearing bright and fluid appearing dark
• T2-weighted and STIR sequences highlight fluid and edema as bright signal, making tears, inflammation, and bone marrow edema visible
• Proton density sequences provide high contrast between cartilage and fluid, ideal for assessing articular surfaces
• MR arthrogram uses injected contrast to distend the joint, improving visualization of partial ligament tears and loose bodies

UCL Assessment on MRI

The ulnar collateral ligament is best evaluated on coronal images. A normal UCL appears as a dark, taut band connecting the medial epicondyle to the sublime tubercle of the ulna. On T2-weighted images, a torn UCL shows high signal within or around the ligament. Partial tears may show thickening with internal signal changes, while complete tears demonstrate discontinuity with surrounding fluid. MR arthrogram increases sensitivity by showing contrast leaking through the torn ligament. For more on UCL injuries, see our guide on elbow injury types.

Epicondylitis on MRI

Lateral epicondylitis (tennis elbow) appears on MRI as increased T2 signal within the common extensor tendon origin, often with tendon thickening. Severe cases show partial tearing with fluid-signal gaps within the tendon. Medial epicondylitis shows similar changes at the flexor-pronator origin. Associated findings may include bone marrow edema at the epicondyle and peritendinous fluid. Learn about healing expectations in our article on tennis elbow healing without surgery.

OCD Lesions on MRI

Osteochondritis dissecans of the capitellum is staged by MRI based on stability. Stable lesions show subchondral bone changes with intact overlying cartilage. Unstable lesions demonstrate a high-signal line between the fragment and parent bone on T2 images, indicating fluid undermining the fragment. Detached fragments appear as loose bodies within the joint. MRI staging directly guides whether conservative or surgical treatment is appropriate.

Key Takeaways

• T2-weighted sequences are the workhorse for detecting tears, edema, and inflammation
• The UCL is best seen on coronal images and may require MR arthrogram for subtle tears
• Epicondylitis shows as tendon signal changes and thickening at the epicondyle
• OCD lesion stability on MRI determines conservative versus surgical management

Frequently Asked Questions