Combination of high-resolution and color Doppler ultrasound in diagnosis of carpal tunnel syndrome.

BACKGROUND: Ultrasound has recently emerged as a diagnostic tool in carpal tunnel syndrome (CTS).

PURPOSE: To evaluate the utility of a combination of high-resolution and color Doppler ultrasound as an alternative to electrodiagnostic tests (EDT), in CTS diagnosis, and to define an ultrasonographic prediction model for CTS.

MATERIAL AND METHODS: A total of 85 patients with certain clinical diagnosis of CTS and 49 healthy controls were enrolled. High-resolution and color Doppler ultrasound were performed and the cross-sectional area (CSA), hypoechogenicity, and hypervascularity of the median nerve were evaluated. Receiver-operating characteristic curves were used to determine the optimal cut-off point of median nerve CSA in diagnosis of CTS. Multivariate logistic regression analysis was used to formulate a prediction model for CTS.

RESULTS: The optimal cut-off point of median CSA in wrist was 10.5 mm(2). Hypervascularity (OR = 37.95), hypoechogenicity (OR = 12.30), and high CSA (OR = 34.79) of median nerve were significantly (P < 0.001) higher in CTS patients than in controls. No significant difference was found between the sensitivity and specificity of EDT and any of the above indices in prediction of CTS. An ultrasonographic model for prediction of CTS, comprised hypervascularity and/or high CSA of median nerve, could predict the CTS probability between 87-99%. The sensitivity and specificity of this model (86% and 84%) was not different from EDT (80% and 84%).

CONCLUSION: A combination of high-resolution and color Doppler ultrasound can be used as a non-invasive alternative to EDT in diagnosis of CTS.