Assessment of the carpal tunnel syndrome by high-frequency ultrasound images of the wrist: A feasibility study

Ultrasound images have been frequently applied to diagnose the carpal tunnel syndrome (CTS) based on the analysis of morphological information in the median nerve. Yet the image resolution of most current clinical ultrasound scanners was not able to provide substantial sensitivity and quantitative information for the diagnosis. To jump over this hurdle, a 30 MHz high frequency ultrasound system and image processing scheme were developed to obtain morphology of the median nerve and the kinetic information from tissues in the wrist. The synthetic aperture focusing technique with adaptive weighting was utilized to improve the spatial resolution and signal-to-noise ratio of acquired images. The kinetic information of the wrist was obtained from analyzing a correlation of ultrasonic images associated with movements of extended fingers and those of flexed fingers. The correlation coefficients varied from 1 to 0.74 ± 0.09 corresponding to fingers from extended to flexed movements. This study demonstrated that high frequency ultrasound could be applied to diagnose CTS.