High-resolution ultrasonography of the TMJ: helpful diagnostic approach for patients with TMJ disorders ?

PURPOSE: The purpose of this study was to investigate patients with a clinical diagnosis of internal derangement to determine the diagnostic value of static high resolution ultrasonography (HR-US) when compared with magnetic resonance imaging (MRI).

PATIENTS: Sixty-six patients (132 temporomandibular joints [TMJs]) with a clinical diagnosis of internal derangement were investigated by HR-US and MRI.

METHODS: MRI and HR-US investigations were performed by experienced radiologists. The sonograms were done with a real-time 12-Mhz linear-array scanner. The HR-US interpretation errors were re-evaluated retrospectively by the same radiologist knowing the MRI results by comparing these with the 'prospective' and 'retrospective' diagnoses. The prospective and retrospective diagnoses were also compared with each other.

RESULTS: Eighty-seven of the 132 TMJs had a disc displacement proved by MRI in the closed-mouth position. At maximum mouth opening, 54 TMJs had a disc displacement. The prospective interpretations showed a sensitivity and specificity of 78% each, accounting for an accuracy of 78%. At maximum mouth opening, HR-US resulted in a sensitivity of 61%, a specificity of 88% and an accuracy of 77%. The retrospective interpretations yielded a sensitivity of 90%, a specificity of 84% and an accuracy of 88% in the closed-mouth position. At maximum mouth opening, HR-US showed a sensitivity of 73%, a specificity of 95% and an accuracy of 86%.

CONCLUSION: HR-US is suitable for the detection of disc displacements in the TMJ. However, further studies may be warranted to reduce the proportion of false-positive interpretations, thereby avoiding the application of unnecessary treatment.