Abstract
Several non-invasive tests to evaluate the degree of arteriosclerosis (DA) are utilized for the diagnosis. However, the DA estimated by a test cannot be verified because it is difficult to measure the elasticity of artery extracted anatomically from subjects who are received the non-invasive test. Conventionally, the validity of a new test developed for estimating the DA has to been evaluated by examining cross-correlation between DA estimated by the new test and other similarly unverified test, or dependency of the measured DA on age of subjects. We focus on carotid ultrasonography, one of tests for evaluating the DA. By observing carotid artery in ultrasonography, if the magnitude of carotid diameter changes accompanied with heart beat normalized by difference of systolic and diastolic blood pressures becomes smaller, it is considered that carotid artery is more elastic, i.e., arteriosclerosis is more progressing. We pointed out that the elasticity of carotid artery is estimated higher for a subject who has more elastic surrounding tissues around carotid artery because the tissues suppress the movement of artery.
