Colour Doppler sonographic analysis of blood-flow velocity in the human facial artery and changes in masseter muscle thickness during low-level static contraction

Muscle oedema, which can be seen as a thickness increment by ultrasonograph y, is important in provoking pain and fatigue during low-level contraction. Although oedema is related to the balance of inflow and outflow of blood, there are no data on the correlation between muscle thickness change and bl ood-flow. Blood-flow velocities in the facial artery and the muscle thickne ss changes were measured by colour Doppler ultrasonography in 30 healthy vo lunteers during 20 min contraction with 10% of maximum force. Thickness and velocity changes both reached a peak in the initial phase of contraction. The initial change of thickness did not correlate with the velocity in the facial artery, while those immediately after exercise showed a high correla tion. The velocity changes in the facial artery might depend on both the ge neral response to contraction and local metabolic or mechanical factors in the contracted masseters. (C) 2001 Elsevier Science Ltd. All rights reserve d.