The purpose of this study was to determine the accuracy of MR arthrography (MRA) in the classification of SLAP lesions. We investigated 24 shoulders with arthroscopically proven SLAP lesions of the shoulder. The average age was 29 years old (16-60 years old) and all cases were male. MR arthrography (MRA) was performed before arthroscopic operation in all cases. Based on the Snyder's classification, we defined the diagnostic criteria for a classification of SLAP lesion on MRA. Sensitivities, specificities and accuracies between the classification on MRA and arthroscopic findings were calculated. In MRA,8 shoulders were diagnosed as type I,15 type II and 1 type IV. In arthroscopic findings,3 of 8 shoulders classified as type I in MRA were type II, and 5 of 15 shoulders classified as type II in MRA were type I. One type IV case was assessed correctly in MRA. MRA showed a sensitivity of 50 %, a specificity of 79 % and an accuracy of 67 %in type I, and a sensitivity of 77 %, a specificity of 55 % and an accuracy of 67 % in type II. MRA classification and arthroscopic findings were concurrent in 16 (67 %) of 24 shoulders. MR arthrography is a highly effective method for the detection of SLAP lesions, but this technique is limited in the classification of different types of SLAP lesions.
