Diagnostic accuracy on fat-saturated T2 weighted MRI for diagnosis of intra-articular adhesions of the temporomandibular joint.

OBJECTIVE: The purpose of this study is to compare intra-articular adhesions of the temporomandibular joint (TMJ) between fat-saturated T2 weighted MR images and arthroscopic findings. METHODS: 50 patients (50 joints) with closed locking of the TMJ who were examined with MRI and then underwent arthroscopic surgery participated in this study. The concordance rate of intra-articular adhesions between fat-saturated T2 weighted MR images and arthroscopic findings was studied using the kappa coefficient. RESULTS: Intra-articular adhesions were seen on MRI in 21 joints (42%) and in arthroscopic findings in 26 joints (52%). Thus, five joints had false-negative results and mild adhesions were arthroscopically observed in these five joints. There was significant concordance between these two findings (p<0.001). The kappa coefficient was 0.801, which was considered to be complete concordance. CONCLUSIONS: On fat-saturated MRI, a low signal intensity area and narrowing image in the joint space of the TMJ may indicate the presence of intra-articular adhesions or fibrosis.