Ultrasound assessment of increased capsular width as a predictor of temporomandibular joint effusion.
OBJECTIVE
The aim of this study was to evaluate whether an increased capsular width evidenced by ultrasound (US) could be an indirect marker of temporomandibular joint (TMJ) effusion.


METHODS
138 TMJs were evaluated by US and magnetic resonance imaging (MRI) by two blinded calibrated investigators. US measures of capsular width (in mm) and MRI diagnosis of TMJ effusion (presence/absence) were used to perform a receiver operating characteristic (ROC) curve analysis in order to assess the most accurate cut-off value of capsular width that was able to discriminate between joints with and without MRI effusion.


RESULTS
Diagnostic accuracy of US to detect MRI-depicted TMJ effusion was good (area under the ROC curve=0.817). US sensitivity was high for values below the cut-off value of 1.950 mm (true positive rate (TPR)=83.9%; false positive rate (FPR)=26.3%), while specificity was high for values above the cut-off value of 2.150 mm (TPR=71.0%; FPR=11.8%).


CONCLUSIONS
Analysis of ROC curve appears to reveal that the critical area is around the 2 mm value for TMJ capsular width. These findings need to be refined by further studies assessing the smallest detectable difference in capsular width, with attention to reliability of interobserver observations.
Manfredini
D
D
Section of Prosthetic Dentistry, Department of Neuroscience, University of Pisa, Italy. daniele.manfredini@tin.it
Tognini
F
F
Melchiorre
D
D
Zampa
V
V
Bosco
M
M
D019540:Area Under Curve; D002358:Cartilage, Articular / Q000000981:diagnostic imaging / Q000473:pathology; D005122:Exudates and Transudates; D005189:False Positive Reactions; D006801:Humans; D017746:Joint Capsule / Q000000981:diagnostic imaging* / Q000473:pathology; D008279:Magnetic Resonance Imaging; D012372:ROC Curve; D012680:Sensitivity and Specificity; D016037:Single-Blind Method; D013582:Synovial Fluid / Q000000981:diagnostic imaging*; D013704:Temporomandibular Joint / Q000000981:diagnostic imaging* / Q000473:pathology; D019224:Temporomandibular Joint Disc / Q000000981:diagnostic imaging / Q000473:pathology; D013705:Temporomandibular Joint Disorders / Q000175:diagnosis / Q000000981:diagnostic imaging; D014463:Ultrasonography