THE DIAGNOSTIC-VALUE OF ULTRASONOGRAPHY TO DETERMINE THE TEMPOROMANDIBULAR-JOINT DISK POSITION

Objective. Temporomandibular joint (TMJ) arthrography and magnetic res onance imaging are the imaging techniques of choice in patients presen ting with signs and symptoms of TMJ disorders suggesting soft tissue p athosis. With the disadvantage of arthrography as an invasive procedur e and magnetic resonance imaging posing a problem in clinical availabi lity and cost, the purpose of this study was to determine whether ultr asonography could be used to assess the presence or absence of disk di splacement in patients with TMJ disorders. Study design, In 17 patient s, 100 TMJ positions were investigated by static and dynamic ultrasono graphy to analyze the disk-condyle relationship. To compare the respec tive findings with those of a diagnostic method offering high accuracy coronal and sagittal magnetic resonance imaging was carried out immed iately afterwards. Results. With static ultrasonography showing a sens itivity 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 tha t static and dynamic ultrasonography are marginal in detecting the pre sence of disk displacement, but dynamic ultrasonography is sensitive i n 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 resul ts indicate that both modalities are insufficient in establishing a co rrect diagnosis for the presence or absence of disk displacement. Conc lusion. In view of the fact that dynamic ultrasonography proved to be a reliable diagnostic aid for the detection of normal disk position, t he results of this study should be of further interest and encourage r esearch in its potential uses and diagnostic capabilities.