M. Siebler
Mediclin /Essen Kettwig, Department of Neurorehabilitation/ University of Duesseldorf – Essen, Germany
Objective: By means of ultrasound (US) methods structural and functional properties of the muscle tissue could be detected in patients in real time and non-invasively. Using tissue velocity imaging (TVI) we are able to investigate the dynamics of movements in identified muscles. We tested whether this method could be applicated to measure the forearm muscle motions in order to monitor rehabilitation therapies and pharmacological effects.
Material and Methods: The voluntary movement of hand opening (M.ext. digitorum) and closing (M.flexor digitorum) was analyzed in healthy subjects (n=30) and stroke patients (n= 31) using the B-mode and tissue velocity imaging (TVI). TVI is based on the Doppler effect to record slow movements of the tissue and was adapted on a 6-8 MHz probe. We recorded synergistic contractions or dephasing (non-synchronous muscle activity) and quantified velocity of contraction and relaxation as well as there repetition frequency.
Results: Normal subjects displayed a synchroneous activation of the muscles with a contraction velocity of 4.1 cm/s, relaxation velocity of 4.3 cm/s and a repetition frequency of 4.5 cm/s, respectively (mean values). In stroke patients, a significant reduction of these parameters are found on the lesion side (1.1 cm/s; 1.2 cm/s; 1.2/s). A significant decrease was also found on the contralateral healthy side (2.5 cm/s; 2.6 cm/s; 2.5/s) which is also significant different to healthy controls. After 2 weeks rehabilitation exercises these parameters improved in a wide range (up to normal) on both sides. L-Dopa (n=3 patients) improved substantially the parameters within 1 week.
Conclusion: This US technique is a simple and bedside method which allows to analyze and quantify the movement kinetic of identified muscles. This allow to monitor disease progression and treatment effects and may be thereby an appropriate tool for clinical application e.g. in stroke rehabilitation.
Key words: myosonology, tissue velocity imaging, ultrasound.