Comparison of computed with conventional tomography in the evaluation of temporomandibular joint disease: a study of autopsy specimens.

Autopsy specimens were examined both radiographically and macroscopically to compare direct computed tomography (CT) with conventional tomography (CVT) for their diagnostic yield of the structural bone changes in the temporomandibular joint (TMJ). Fifteen specimens were examined with corrected sagittal and 12 with corrected frontal tomography. Five joints showed bone exposure and/or disc perforation macroscopically and all of them were correctly diagnosed by both CT and CVT (sensitivity 1.0). However, false-positive diagnoses were also made, resulting in values for specificity which were somewhat lower for CT than for CVT. Frontal images did not reveal any additional 'true' findings compared with sagittal CT or CVT. For single areas of the joints the average sensitivity was low, 0.28 for CT and 0.47 for CVT, but the specificity for the joint as a whole was high with both methods (0.91 and 0.94 respectively). We conclude that CVT is superior to CT in the diagnosis of single structural bone changes but comparable for comprehensive diagnosis of TMJ disease.