Analysis of Criteria for MRI Diagnosis of TMJ Disc Displacement and Arthralgia

摘要

Aims. To improve diagnostic criteria for TMJ disc displacement (DD). Methods. The standard protocol for MRI diagnosis of DD, using a 12 o'clock reference position, was compared to an alternative protocol. The alternative protocol involves the functional relationship between the condyle and articular eminence, using a line perpendicular to the posterior slope of the eminence as a reference for disc position. The disc location was examined using both protocols, and disc diagnoses were compared in their relationship with joint pain. Statistical analyses included P value, sensitivity, specificity, odds ratio, and kappa statistic. Results. 58 MRIs were interpreted. 36 subjects reported arthralgia; 22 did not. Both protocols demonstrated significance (standard P = 0.004, alternative P < 0.001) for the ability to predict arthralgia. The odds of arthralgia increased in DD patients diagnosed by standard methods 9.71 times and in DD diagnosed by alternative means 37.15 times. The diagnostic sensitivity decreased 30% using the alternative versus the standard protocol (0.6389 versus 0.9444), while specificity increased 60% (0.9545 versus 0.3636). Conclusions. A stronger relationship occurs between DD and arthralgia when using a function-based protocol. The alternative protocol correctly identifies subjects without arthralgia, who by standard methods would be diagnosed with DD, as having nondisplaced discs, providing a more clinically relevant assessment of TMJ disc displacement. 1.1. Background and Significance. Temporomandibular joint pain is considered to develop as the result of inflammatory and/or mechanical mechanisms. Gross morphological changes such as deviation in form, disc displacement, adhesions, and osteoarthritic processes can occur with or without the subject's perceiving pain or dysfunction. When do such findings relate to pain and dysfunction? In Westesson's summary regarding the imaging diagnosis of TMJ arthralgia he states, "inflammatory changes correlate strongly with the patient's pain symptoms [and] we are getting closer to imaging the changes that are truly relevant to [these] symptoms". In his study, he focused on the most symptomatic TMJ in each subject, but found a high number of abnormalities consistent with disc displacement and inflammation in the contralateral joint, as well.