Acetabular Labrum Diagnosis and Imaging

Introduction to Labral Tear Diagnosis

The American College of Radiology recommends MR arthrography as the gold standard for evaluating labral tears, due to its superior accuracy compared to non-contrast MRI 1, 2, 3
Non-contrast MRI has limited sensitivity for detecting labral tears, with a sensitivity of 30-80%, meaning it may miss 20-70% of tears that are actually present 1, 2, 3

The American College of Radiology Appropriateness Criteria suggest that MR arthrography is usually appropriate (rated 9/9) for definitive evaluation of labral tears when clinically suspected 2, 3, 4
If labral tear remains clinically suspected, proceeding to MR arthrography is recommended for definitive evaluation 2, 3, 4
An alternative diagnostic option is a diagnostic intra-articular anesthetic injection, which can confirm an intra-articular source of pain if it temporarily relieves symptoms 2, 3, 5

The technical limitations of non-arthrographic MRI include thick overlying soft tissues, inability to distinguish the labrum from adjacent structures, and no joint distension 1
High-resolution non-contrast MRI at 1.5T or 3T may improve visualization in some cases, but requires specialized protocols and experienced musculoskeletal radiologists 1, 2

The American College of Radiology recommends integrating clinical examination, imaging findings, and patient symptoms for diagnosis, rather than relying on imaging alone 2, 3, 4, 6
A "normal" non-arthrographic MRI should not dissuade pursuit of MR arthrography if clinical suspicion for labral tear remains high based on symptoms and physical examination findings 2, 3, 4