SKELETAL-MUSCLE CONTRACTION IN HEALTHY-VOLUNTEERS - ASSESSMENT WITH DOPPLER TISSUE IMAGING

PURPOSE: To evaluate Doppler tissue imaging (DTI) in the measurement a nd characterization of skeletal muscle movement and contraction. MATER IALS AND METHODS: Five healthy male subjects were examined with a comm ercially available ultrasound imaging unit modified for DTI. Velocitie s of the rectus femoris and gastrocnemius-soleus muscle motion were me asured during the patellar and ankle reflexes, respectively. Velocity profiles were analyzed after digitization of the DTI images. Time to p eak velocity, velocity range, and relaxation time were examined in eac h case over three contractions. For reflex contractions, reproducibili ty was examined by determining the latency period, area under the velo city curve, and duration of contraction for each of five consecutive r eflexes. RESULTS: Isotonic muscle contraction could be distinguished f rom passive movement by a higher tissue velocity range, by a more rapi d initial acceleration slope, and by the velocity differential across the muscle. The intensity and duration of the contraction and plateau and relaxation phases of isotonic contraction could be measured in all muscle groups. CONCLUSION: DTI provides detailed information about th e dynamics of skeletal muscle contraction.