Superior labrum anterior-posterior lesions: Diagnosis with MR arthrographyof the shoulder

PURPOSE: To determine the accuracy of magnetic resonance (MR) arthrography: in the diagnosis of superior labrum anterior-posterior (SLAP) lesions of th e shoulder. MATERIALS AND METHODS: From January 1995 to June 1998, MR arthrography of t he shoulder was performed in 159 patients with a history of chronic shoulde r: pain or instability. Fifty-two patients underwent arthroscopy or open su rgery 12 days to 5 months after MR arthrography. Diagnostic criteria for SL AP lesion included marked fraying of the articular aspect of the labrum, bi ceps anchor avulsion, inferiorly displaced bucket handle fragment, and exte nsion of the tear into the biceps tendon fibers. Surgical findings were cor related with those from MR arthrography. RESULTS: SLAP injuries were diagnosed at surgery in 19 of the 52 patients ( 32%). Six of the 19 lesions (32%) were classified as type I, nine (47%) as type II, one (5%) as type iii, and three (16%) as type IV. MR arthrography had a sensitivity of 89% (17 of 19 patients), a specificity of 91% (30 of 3 3 patients), and an accuracy of 90%,(47 of 52 patients). The MR arthrograph ic classification showed correlation with the arthroscopic or surgical clas sification in 13 of 17 patients (76%) in whom SLAP lesions were diagnosed a t MR arthrography. CONCLUSION: MR arthrography is a useful and accurate technique in the diagn osis of SLAP lesions of the shoulder. MR arthrography provides pertinent pr eoperative information with regard to the exact location of tears and grade of involvement of the biceps tendon.