The diagnostic value of ultrasonography to determine the temporomandibular joint disk position

Temporomandibular joint (TMJ) arthrography and magnetic resonance imaging are the imaging techniques of choice in patients presenting with signs and symptoms of TMJ disorders suggesting soft tissue pathosis. With the disadvantage of arthrography as an invasive procedure and magnetic resonance imaging posing a problem in clinical availability and cost, the purpose of this study was to determine whether ultrasonography could be used to assess the presence or absence of disk displacement in patients with TMJ disorders.

In 17 patients, 100 TMJ positions were investigated by static and dynamic ultrasonography to analyze the disk-condyle relationship. To compare the respective findings with those of a diagnostic method offering high accuracy, coronal and sagittal magnetic resonance imaging was carried out immediately afterwards.

With static ultrasonography showing a sensitivity of 0.41 and a specificity of 0.70 and dynamic ultrasonography a sensitivity of 0.31 and a specificity of 0.95, the data revealed that static and dynamic ultrasonography are marginal in detecting the presence of disk displacement, but dynamic ultrasonography is sensitive in detecting the absence of disk displacement. However, with a positive predictive value of 0.61 and a negative predictive value of 0.51 for static ultrasonography, and a positive predictive value of 0.88 and a negative predictive value of 0.55 for the dynamic technique, the results indicate that both modalities are insufficient in establishing a correct diagnosis for the presence or absence of disk displacement.

In view of the fact that dynamic ultrasonography proved to be a reliable diagnostic aid for the detection of normal disk position, the results of this study should be of further interest and encourage research in its potential uses and diagnostic capabilities.