Diagnostic imaging of unstable superior glenoid labral detachment: a comparison between MR arthrography and unenhanced MRI

We compared efficacy of magnetic resonance arthrography (MRA) and magnetic resonance imaging (MRI) for the detection of superior glenoid labral detachment, and especially unstable superior labrum anterior-posterior (SLAP) type 2 lesions. MR imagings and MR arthrograms of 90 shoulders of 90 patients, including 30 shoulders of unstable SLAP 2 lesions, were interpreted by a novice and an expert observer. These results were correlated with arthroscopic findings. For the expert observer, MRI had a sensitivity of 53%, a specificity of 93%, and an accuracy of 80%, which were improved to 60%, 98%, and 85%, respectively, by MRA. These increases were statistically insignificant. For the novice observer, MRI had a sensitivity of 45%, a specificity of 80%, and an accuracy of 64%, which were significantly improved to 76%, 83%, and 80%, respectively, by MRA. In detecting unstable SLAP 2 lesions, MRA proved to be useful to a novice interpreter, but not significantly useful to an experienced interpreter, compared with unenhanced MRI. We advocate MRA as the examination of first choice for detecting unstable SLAP 2 lesions if they are strongly suspected clinically.