The Clinical Value Of High-Frequency Ultrasound In Diagnosis Of Carpal Tunnel Syndrome

Objective:By researching sonographic characteristics and quantitative indicators in high-frequency ultrasound of carpal tunnel syndrome (CTS), the aim of research was to discuss the clinical value of high-frequency ultrasound in diagnosis and treatment of CTS.Methods:44 patients, total of 73 sides confirmed with electrophysiology and 41 healthy volunteers, total of 67 sides were examined on high frequency ultrasound. The morphology, direction variation and echo changes of median nerve were observed, the thickness of the median nerve at the levels of pisiform bone and hamate hook was measured in sagittal plane. The cross-sectional area of the median nerve at the levels of pisiform bone and hamate hook and the thickness of transverse carpal ligament at the level of hamate hook were measured in transverse plane. The thickness ratio and cross-sectional area ratio of the median nerve were calculated. The measurements of the two groups were compared in statistical analysis. The diagnostic threshold, sensitivity and specificity of all indexes being measured were determined by the curve of Receiver Operating Characteristic (ROC). The ultrasonic measurements in patients with CTS in different stages were compared.Results:The echo of median nerve reduced, the membrane of nerve thickened and the internal structure showed unclearly in CTS group. The level of hamate hook was the commonest position when compressed, where nerve diminished and markedly swollen at both ends. Compared with the control group, the thickness ratio, the cross-sectional area ratio, the cross-sectional area at the level of pisiform bone and the transverse carpal ligament thickness significantly increased in CTS group (P<0.001). Optimum cut-off value for the thickness ratio, the cross-sectional area ratio, the cross-sectional area at the level of pisiform bone and the transverse carpal ligament thickness were 1.234,1.209,0.110cm2, 0.341cm, the corresponding sensitivity were 89.0%,90.4%,80.8%,90.4%and specificity were 89.6%,83.6%,89.6%,92.5%, respectively. The difference of cross-sectional area at the level of pisiform bone were statistically significant in the early, middle and late stage CTS groups, the difference of thickness ratio and cross-sectional area ratio were statistically significant in middle stage CTS group comparing with middle and late stage CTS groups, the difference of the thickness ratio and cross-sectional area ratio had no statistical significant between middle and late stage CTS groups.Conclusion:The morphology and location compressed of median nerve in carpal tunnel are clearly displayed with high frequency ultrasound, which provides the anatomical information of carpal tunnel and is of higher value in diagnosis of CTS, therefore it may be a feasible assessment for carpal tunnel syndrome in diagnosis of CTS.