Direct MR arthrography of plica synovialis mediopatellaris

Objective: To evaluate the efficacy of direct MR arthrography for diagnosin g plica synovialis mediopatellaris (PSM). Material and Methods: Twenty-two knees of 19 patients were examined by dire ct MR arthrography. In 19 of those knees, held-echo T2*-weighted transaxial images were obtained with intra-articular administration of 40 ml of salin e ("direct MR arthrography"). In the other 3 knees, TI-weighted transaxial images were obtained with intra-articular administration of 40 ml of gadope ntetate dimeglumine. Conventional MR images were evaluated prior to direct MR arthrography in 12 of the 22 knees. The results of direct MR arthrograph y and conventional MR imaging were compared with the arthroscopic findings. Results: Direct MR arthrography demonstrated 17 of 19 PSMs proved on arthro scopy. The features of 16 PSMs on direct MR arthrography corresponded accur ately with the arthroscopic classification. Conventional MR demonstrated on ly 3 plicae. Conclusion. Direct MR arthrography enabled accurate diagnosis of PSMs and c ould replace diagnostic arthroscopy.