A Comparison of Diagnostic Usefulness of Sonography and Electrophysiologic Study in Patients with Carpal Tunnel Syndrome

Kim, Dong Hyun; Park, Dong Sik; Kang, Hyun Jung; Lee, Ju Youn; Nam, Hee Seung

Abstract

OBJECTIVE
To compare the diagnostic accuracy of ultrasonography(US) and electrophysiologic study in patients with carpal tunnel syndrome (CTS). METHOD: Two hundred twenty-seven hands in patients and 40 hand in healthy control group were used. Patients were diagnosed clinically with CTS. All groups had nerve conduction study (NCS) and sonographic measurement of the cross-sectional area (CSA) of the median nerve. Using the receiver operating characteristic curve, the optimal cutoff value was obtained and the sensitivity and specificity was evaluated. The correlation between the Hi-Ob score and the electrophysiologic severity, Hi-Ob score and CSA of the median nerve, and between the electrophysiologic severity and CSA were assessed.
RESULTS
The cutoff value of the difference of median sensory latency (DMSL) was 1.55 ms with a sensitivity and specificity of 94.7% and 92.3% respectively. The cutoff value of CSA was 9.5 mm2, had a sensitivity of 85.5% and a specificity of 92.3%. In mild CTS, NCS showed a sensitivity of 92.1% and CSA showed a sensitivity of 81.2%. The electrophysiologic severity and Hi-Ob score appeared to show a significant positive correlation (r=0.34, p<0.01), and as the Hi-Ob score increased, the CSA was increased (r=0.54, p<0.01). The increase in electrophysiologic severity and the CSA also showed a significant correlation (r=0.33, p<0.01) There was bifurcation of the nerve in 9 hands, persistent median artery in 4 hands and cyst in 1 hands. And tenosynovitis was observed in 1 hands.
CONCLUSION
In clinical CTS, electrophysiologic study showed higher sensitivity than US. But US can give us anatomical informations.