Simultaneous measurement of vibrations on the arterial wall downstream and upstream from an atherosclerotic lesions

In the literature, it has been reported that cerebral ischemia paroxysm and cerebral infarctions occurs with high percentages when the inner diameter is decreased less than 70% due to a stenosis. The most primary reason of these events is rupture of atherosclerotic plaques of the carotid artery. However, it is difficult to noninvasively predict the rupture. For solving this problem, we have investigated the influence of blood flow on the atherosclerotic plaque by transcutaneously measuring small vibrations caused by the pulsatile flow on the arterial wall. In this paper, small vibrations on the carotid arterial wall are measured and analyzed for patients with atherosclerosis and for healthy subjects. From in vivo experimental results, high frequency components were present in the resultant small vibrations on the wall of downstream from the atherosclerotic plaque. Moreover, from experiments using a silicone tube with small pressure sensors, it is found that there is close relationship between the vibrations and inner pressure for both cases with and without an artificial stenosis. These results might open the possibility to predict rupture of atherosclerotic plaques in future by measuring the small vibrations arterial wall.