High-resolution ultrasonography of cross-sectional area of median nerve compared with electro-diagnostic study in carpal-tunnel syndrome

Carpal tunnel syndrome is a common chronic entrapment neuropathy. The present study evaluated the diagnostic ability of ultrasound (US) in measuring the cross-sectional area of the median nerve in the entrance of the carpal tunnel area in comparison with electrodiagnostic testing for diagnosing carpal tunnel syndrome. In this cross-sectional study, 253 patients with carpal tunnel syndrome based on American Academy of Neurology clinical symptoms were selected for participation. After screening, 200 patients were enrolled in the study. Wrist US and electrodiagnostic findings for patients were compared. Data were analyzed by SPSS. There was a good agreement between sonographic and electrodiagnostic findings [right hand (kappa= 0.71), left hand (kappa= 0.78)]. For the right and left hands, respectively, ultrasound sensitivity (89% vs 90%), specificity (90% vs 89.2%), positive predictive value (84.7% vs 94.7%), and negative predictive value (75.7% vs 81.6%) were calculated. High-resolution ultrasound of the median nerve cross-sectional area is an accurate test for diagnosing carpal tunnel with an acceptable level of diagnostic ability. In comparison with the electrodiagnostic test, ultrasonography can provide more practical information about anatomical changes in the tunnel, which can be considered in selecting treatment options.