Superior labral anterior posterior (SLAP) lesions of the glenoid labrum: Reliability and accuracy of MR arthrography for diagnosis

PURPOSE: To determine the reliability and accuracy of magnetic resonance (M R) arthrography for the diagnosis of superior labral anterior posterior (SL AP) tears. MATERIALS AND METHODS: The MR arthrograms in 80 patients who underwent arth roscopy and MR arthrography during a 54-month period were retrospectively r eviewed. MR arthrograms were independently scored by three observers for th e presence and type of SLAP lesion. Type I SLAP lesions were regarded as ne gative as they most often are not clinically relevant. Interobserver agreem ent for detection of SLAP lesions was calculated by using kappa coefficient s. The differences in areas under the receiver operating characteristic (RO C) curves were assessed with a univariate z score test. RESULTS: At arthroscopy, there were 25 SLAP tears: type II (n = 22), type I II (n = 2), and type IV (n = 1). Sensitivity, specificity, and accuracy of each reader were 92%, 84%, and 86%; 92%, 82%, and 85%; and 84%, 69%, and 74 %, respectively. Interobserver agreement for SLAP tears was substantial (ka ppa = 0.77) to moderate (kappa = 0.52, kappa = 0.44). The areas under the R OC curves for each reader were 0.94, 0.93, and 0.83, which were not signifi cantly different. CONCLUSION: MR arthrography of the shoulder is reliable and accurate for de tection of SLAP tears.