Transcutaneous detection of relative changes in artery diameter.

The extent of the excursions of the arterial walls during the cardiac cycle depends on both the compliance of the vessel wall and the local pressure fluctuations. Simultaneous assessment of the relative change in artery diameter in combination with the velocity distribution along the vessel cross section can reveal the cause of loss of distensibility. As will be demonstrated, a multigate pulsed Doppler system with a high spatial resolution can perform simultaneously both functions. The relative change in diameter during the cardiac cycle is obtained by taking the ratio of the distension and the diameter of the artery as observed along the ultrasound beam. It can be shown that this ratio will be angle independent. Statistical and experimental evaluations demonstrate that the system allows the assessment of the relative change in diameter of major peripheral arteries as a continuous function of time with an accuracy of about 0.5%.