2002 年 15 巻 1 号 p. 20-33
Carotid atherosclerosis is known to be a useful indicator of ischemic cerebrovascular disease and ischemic heart disease. Noninvasive ultrasonic assessment is a standard method for screening of carotid artery disease. This report is to certify the consensus in Japan for evaluating carotid atherosclerosis by ultrasonography.
The ultrasonic device employed needs to have a linear array transducer of over 5 MHz and/or similar ultrasonic ability. A Doppler subunit is a useful optional tool for evaluating blood flow velocity, which is an important parameter for assessing severe vascular lesions. Complete ultrasonic evaluation of the carotid artery tree must be done from the common carotid artery and carotid bulb to the internal carotid artery. Among several parameters, we selected the maximum intima-media thickness (max-IMT) of the whole carotid artery as the most valuable for assessing carotid atherosclerosis. Max-IMT on the far wall of the common carotid artery is a stable and essential item. In this report, max-IMT indicates the maximum wall thickness including the plaque lesion. Plaque score and mean IMT are optional authorized parameters of carotid atherosclerosis. Percentage area reduction is a standard ultrasonic measurement method for stenosis. Lesion echogenicity is expressed as hypo-, iso or hyperechoic. Medical management will depend on the severity of carotid atherosclerosis evaluated by ultrasonography.