High-resolution ultrasound imaging compared to magnetic resonance imaging for temporomandibular joint disorders: An in vivo study.

Purpose: The study aims to determine the diagnostic value of high-resolution ultrasonography (US) compared with magnetic resonance imaging (MRI) for the evaluation of temporomandibular disorders (TMD).
Methods: Fifty consecutive patients (42 female and 8 male) with signs and symptoms of TMD according to the Research Diagnostic Criteria for TMD were enrolled in the study. Each patient underwent US (13 and 20 MHz) and MRI examination of both TMJs, 1-7 days following clinical examination. All MRI examinations were performed by another radiologist using an 1.5 T MRI device. Sensitivity (Se), specificity (Sp), positive and negative predictive values (PPV, NPV) and diagnostic accuracy were computed along with 95% confidence intervals.
Results: For overall disc displacements, 13 MHz US showed a Se of 72.58%, Sp of 86.84%, PPV of 90%, NPV of 66% and diagnostic accuracy of 78%, while 20 MHz US showed a Se of 75.81%, Sp of 86.84%, PPV of 90.38%, NPV of 68.75% and a diagnostic accuracy of 80%. For degenerative changes, 13 MHz US revealed a Se of 58.33%, Sp of 92.11%, PPV of 70%, NPV of 87.5% and a diagnostic accuracy of 84%, whereas 20 MHz US indicated the same Se of 58.33%, Sp of 93.42%, PPV of 73.68%, NPV of 87.65% and a diagnostic accuracy of 85%. The Cohen's Kappa coefficient for the intra- and inter-observer agreement was 0.822 and 0.836 for disc displacement, respectively 0.813 and 0.788 for degenerative disorders (p < 0.001).
Conclusions: High-resolution US could be a useful imaging technique in diagnosing TMJ disc displacements.
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