Detectability of disk perforation on MR imaging in TMJ disorders

Magnetic resonance imaging (MRI) is capable of providing anatomical configulations and structures of the temporomandibular joint (TMJ) without invasive procedures. However for evaluating disk perforation, invasive imaging modelities are mandatory like as arthrography and arthroendoscopy. Objectives: This study was undertaken to evaluate the detectability of disk perforation at MR imaging. Methods: MRI and arthrotomographic studies were performed in 33 patients (25 females, 8 males) with a mean age of 35.2 years ( 14 to 77 years). Proton density-weighted and T2-weighted protocols were used for the sagital and coronal plane images by a 1.0 Tesla MR scaner. Perforation of the disk was evaluated by dual-space double contrast arthrotomography. Results: Perforation of the disk was confirmed in 11(33%)jof the 33 joints by arthrography. MR image findings of disk position in perforation joints were normal disk position in 2 joints (18.2%), disk displacement with reduction in 2 joints (18.2%) and disk displacement without reduction in 7 joints (63.6%). MR image findings of non-perforation joints were normal disk position in 4 joints (18.2%), disk displacement with reduction in 5 joints (22.7%) and disk displacement without reduction in 13 joints (59.1%). Disk forms in 11 perforation joints were biconvex in 5 joints (45.5%) , enlargement in 4 joints (36.4%), biplaner in 1 joint (9.0%) and biconvex in 1 joint (9.0%). In non-perforation joints, disk forms were biconvex in 3 joints (13.7%) , enlargement in 8 joints (36.4%), biplaner in 6 joints (27.3%) and biconvex in 5 joint (22.7%). The incidence of joint effusion were 72.2% (8/11) and 72.2%(16/22 cases), in perforation disks and non-perforation disks, respectively. There were no significant difference between the two groups (p>0.1). Conclusions: The results of this study suggest that the position and configuration of the disk, and joint effusion on MRI are not relevant to disk perforation in TMJ disorders.