Detection of kinetic information in the wrist using high-frequency ultrasound

The motion of the wrist provides a direct information for assessing the carpal tunnel syndrome (CTS). In this study, a 30 MHz high-frequency ultrasound (HFU) system was used to measure the displacement characteristics of the median nerve and the kinetic information in the carpal tunnel. In vivo experiments were performed on the right wrist of 10 healthy volunteer. Echo signals were collected from tissues associated with the movements of fingers from extension to flexion at different angles. To improve signal-to-noise ratio of HFU signals, the synthetic aperture focusing technique with adaptive weighting was utilized. The kinetic information of the wrist was obtained by calculating the correlation coefficient of signals of a tracked tissue from two consecutive time frame of HFU images. Results showed that the displacement of the tendon and median nerve tend to be the largest as the corresponding fingers flex at 85 degree; that of the muscle belly is the largest associated with the fingers flex at 55 and 85 degree. The correlation coefficients varied from 1 to 0.85 corresponding to fingers move from extended to flexed positions. This study demonstrated that high frequency ultrasound could be applied to diagnose CTS.