Sonographic and electrophysiological detection in patients with carpal tunnel syndrome

To assess prospectively the significance of sonographic measurements of the median nerve in the diagnosis of carpal tunnel syndrome (CTS), to look for proper parameters and cutoff values for the sonographic diagnosis, and to correlate with the electrophysiological findings.

This study involved 30 patients, who were clinically diagnosed as CTS merely based on their symptoms and signs; and 30 healthy volunteers were served as controls. Eligible subjects underwent sonographic and electromyographic detection.

In the CTS patient group, the cross-sectional area (CSA) at the pisiform bone level (CSA2) and the diameter (D) of the median nerve increased. When the cutoff values of CSA2 and D were 0.105 cm(2) and 0.195 cm, the sensitivity, specificity and accuracy of the diagnosis were 91.5, 94.5, 94.1%, and 90.7, 80.4, 86.5%, respectively. Both CSA and D were negatively related to sensory conduction velocity, while CSA was positively related to distal motor latency.

There is a good association of sonographic with electrophysiologic detection for the diagnosis of CTS.