The non-invasive functional tissue characterization for arteriosclerosis by artery wall motion analysis with time series high-speed echo images and continuous sphygmomanometer

Evaluation methods for arteriosclerosis have been established, but most of them are invasive. In recent years, noninvasive diagnosis for arteriosclerosis can be achieved by high resolution echography. However, even this new diagnostic method cannot diagnose until the beginning of the morphologic changes of the arteries by stenosis. There is little value achieved if the arteriosclerosis is detected after the stenosis of the arteries has progressed. Also, we thought that a noninvasive method for evaluating the arteriosclerosis should be used. We introduced a idea of rheological dynamics into analysis. For example the cross-section area of a young elastic artery may expand quickly and become wide, whereas an old one is narrow and slowly expands due to blood pressure. We call this functional tissue characterization, and investigated the common carotid artery of about 160 persons. In this way we diagnosed age-related arteriosclerosis quantitatively by investigating parameters of the nonlinear pressure and area of the common carotid artery curve. Furthermore, we were able to separate a hypertension group and a physically normal group quantitatively as a result of having evaluated the arteriosclerosis due to various vascular diseases.