Ultrasonographic vs. magnetic resonance imaging findings of temporomandibular joint effusion

The aim of this study was to assess the accuracy of ultrasonography (US) in the evaluation of temporomandibular joint (TMJ) effusion compared with magnetic resonance imaging (MRI) findings, assumed as the gold standard. METHODS: The study group consisted of 44 patients with signs and symptoms of temporomandibular disorders (TMD). Each joint (N=88) was evaluated using US and magnetic resonance (MR) to detect the presence of effusion. The 2 examinations were carried out by 2 blinded operators within no more than 2 weeks from each other. During that period the patients did not receive any kind of treatment. Sensitivity, specificity, positive predictive values (PPV) and negative predective values (NPV) of US were calculated. The agreement between the 2 diagnostic techniques was then evaluated by Cohen's K test. RESULTS: MRI depicted intra-articular effusion in 41 of the 88 TMJs (46.5%) while no effusion was detected in the remaining 47 joints (53.5%). Ultrasonographic imaging revealed effusion in 42/88 joints (47.8%), while the remaining 46 joints (52.2%) showed no effusion. US showed a sensitivity of 75.6% and a specificity of 76.5%. The PPV and NPV were 73.8% and 78.2% respectively. US vs MRI agreement for the diagnosis of TMJ effusion was fairly good (pct. agreement 76.1%; K=0.521). CONCLUSION: US is a low-cost, easy-performing, non-invasive, rapidly-executing imaging technique whose possible employ in the study of the TMJ is very promising.