Comparison of ultrasonography and magnetic resonance imaging in the evaluation of disk displacement of the temporomandibular joint

The aim of this work was to evaluate the accuracy and reliability of ultrasonography in the diagnosis of temporomandibular joint (TMJ) disc position abnormalities compared with magnetic resonance imaging (MRI). Participants in this study were 41 consecutive patients with signs and symptoms of temporomandibular disorders. All 82 TMJs were evaluated to detect disc position abnormalities by means of ultrasonography and MRI, performed by blinded operators. The accuracy of ultrasonography was evaluated with respect to MRI. Ultrasonography demonstrated good accuracy in the evaluation of disc position, showing a sensitivity of 65.8% and a specificity of 80.4%, resulting in a positive likelihood ratio of 3.35, a negative likelihood ratio of 0.42, and a diagnostic odds ratio of 7.97. The predictive positive and negatives values were respectively 77.1% and 70.2% and the overall agreement between the two radiological techniques was 73.1%. Ultrasonography proved to be accurate in detecting normal disc position and the presence of abnormalities in disc-condyle relationship but not so useful for the distinction between disc displacement with and without reduction.