Diagnostic accuracy of ultrasonography compared with nerve conduction studies in carpal tunnel syndrome

Carpal tunnel syndrome (CTS) is the most common entrapment neuropathy of the upper extremity. Ultrasonography (USG) enables measurement of the median nerve cross-sectional area (CSA) and quantitative assessment of hand muscles. This study aimed to evaluate the diagnostic accuracy of USG findings compared with electrophysiological studies in CTS.

In this prospective cross-sectional study, we included 136 wrists from 76 patients presenting to the Neurology Department of Ondokuz Mayıs University between July 2023 and December 2023. Ultrasonographic findings were compared with electrophysiological results.

The cut-off value for median nerve CSA in the diagnosis of CTS was 0.0905 cm², with a sensitivity of 90.3% and specificity of 90.1%. ROC curve analysis revealed an area under the curve (AUC) of 0.948 (95% CI: 0.924-0.973), suggesting excellent discriminative ability. Median nerve CSA was significantly higher in the patient group compared to controls. Thenar muscle thickness was significantly reduced in the CTS group, particularly in severe and extreme stages. No significant difference was observed in hypothenar muscle thickness between groups.

Ultrasonography showed excellent diagnostic accuracy in detecting carpal tunnel syndrome, with high agreement with electrophysiological findings. Among the evaluated parameters, median nerve cross-sectional area and thenar muscle thickness were strong diagnostic indicators. These results support the role of ultrasonography as a reliable, non-invasive diagnostic tool in CTS. Further large-scale, multicenter studies are warranted to confirm these findings and to define standardized diagnostic thresholds.