Doppler ultrasound-based measurement of tendon velocity and displacement for application toward detecting user-intended motion

Abstract

The motivation of this research is to non-invasively monitor the wrist tendon's displacement and velocity, for purposes of controlling a prosthetic device. This feasibility study aims to determine if the proposed technique using Doppler ultrasound is able to accurately estimate the tendon's instantaneous velocity and displacement. This study is conducted with a tendon mimicking experiment consisting of two different materials: a commercial ultrasound scanner, and a reference linear motion stage set-up. Audio-based output signals are acquired from the ultrasound scanner, and are processed with our proposed Fourier technique to obtain the tendon's velocity and displacement estimates. We then compare our estimates to an external reference system, and also to the ultrasound scanner's own estimates based on its proprietary software. The proposed tendon motion estimation method has been shown to be repeatable, effective and accurate in comparison to the external reference system, and is generally more accurate than the scanner's own estimates. After establishing this feasibility study, future testing will include cadaver-based studies to test the technique on the human arm tendon anatomy, and later on live human test subjects in order to further refine the proposed method for the novel purpose of detecting user-intended tendon motion for controlling wearable prosthetic devices.

Application of a novel Kalman filter based block matching method to ultrasound images for hand tendon displacement estimation

“…11,12 Researchers and clinicians have also used commercial ultrasound scanners with pulsed-wave Doppler and color Doppler imaging functions to quantify tendon displacement and velocity. 13 However, previous studies that used Doppler-based techniques to estimate tendon displacements found them to be effective only when the tendon velocity was higher than 25 mm/s. 13 This limitation means that Doppler imaging is not an effective tool for patients with tendon injuries, since the tendon velocity in such patients is normally below 25 mm/s.…”

“…13 However, previous studies that used Doppler-based techniques to estimate tendon displacements found them to be effective only when the tendon velocity was higher than 25 mm/s. 13 This limitation means that Doppler imaging is not an effective tool for patients with tendon injuries, since the tendon velocity in such patients is normally below 25 mm/s.…”