Detectability of anterior displacement of the articular disk in the temporomandibular joint on helical computed tomography - The value of open mouth position

Objective. The purpose of this study was to establish the diagnostic reliab ility of anterior displacement, of the articular disk in the temporomandibu lar joint on helical computed tomography. Study design, Ninety-four consecutive patients were examined through use of both computed tomography and magnetic resonance imaging. On axial computed tomography, anterior disk displacement was defined as the presence of an a rea of soft tissue density that was semilunar in shape and located in front of the mandibular condyle. Results, With magnetic resonance imaging taken as the diagnostic gold stand ard in evaluation of articular disk position, the sensitivity, specificity, and accuracy for computed tomography were 91%, 100%, and 97%, respectively , in the closed mouth position and 96%, 99%, and 98%, respectively, in the open mouth position. Conclusions, The detectability on axial helical computed tomography of ante rior displacement of the articular disk in the temporomandibular joint in t he open mouth position was almost equal to that on magnetic resonance imagi ng. It is recommended that the open mouth position be added when helical co mputed tomography is used to evaluate patients with temporomandibular joint disease.