MR findings of the temporomandibular joint with crepitus

Crepitus is an important sign for diagnosis of arthrosis of the temporomandibular joint (TMJ). The presence of crepitus can be evaluated by the listening test previously proposed by our group. However, TMJ can be diagnosed by MR imaging showing the disc position and related findings including bony changes and joint effusion. This study investigated the relationship between the presence of crepitus and pathology of the joint. Fourteen joints with crepitus diagnosed by the listening test were examined in this study. TMJ was categorized into four types based on findings on double spin echo MR images. The results were as follows: Of fourteen joints with crepitus, five (36%) were showed as normal superior disc position. The remaining 9 joints (64%) were diagnosed with disc displacement, of which, 6 showed reduction, one was without reduction and 2 without reduction were associated with arthrosis. Statistical analysis using the data obtained here and other data showed that the joints with crepitus tended to show disk displacement. There was no significant difference between the degree of certainty about the presence of the crepitus and the distribution of joint pathology. Joint effusion was observed only in the joints with displacement. These results indicated that TMJ with crepitus is associated with varied joint pathology. (author)