Читать книгу Interventional Cardiology - Группа авторов - Страница 29

The combination of high‐frequency ultrasound placed within close proximity to the artery wall generates a high resolution, cross‐sectional image of the full thickness of the artery wall. This enables us to visualize the full circumference of the vessel wall and atherosclerotic plaque, to examine arterial remodeling and to measure the area of plaque within each cross‐sectional image with quantitative techniques. A series of cross‐sectional images throughout a length of the artery is acquired with continuous imaging during catheter withdrawal, extending the quantitation of plaque burden to a volumetric measure. Additionally, intravascular ultrasound (IVUS) provides a unique opportunity to characterize the plaque morphology in the atherosclerotic coronary artery. Although identification of atherosclerotic plaque components is limited, several IVUS signatures have been suggested to be associated with either clinically unstable or a high risk for cardiovascular events in patients with coronary artery disease undergoing percutaneous coronary intervention [106–111]. Indeed, a preliminary pathological study has enhanced these findings with the relationship of the vulnerable IVUS characteristics with lipid contents and necrotic core [112]. These characteristics include atherosclerotic plaques with plaque attenuation characterized by a hypoechoic area with deep ultrasonic attenuation despite the absence of bright calcium (attenuated plaque) (Figure 1.2a), plaque echolucency characterized by an intraplaque zone of absent or low echogenicity (echolucent plaque) (Figure 1.2b), and spotty calcification characterized by the presence of lesions 1 to 4 mm in length containing an arc of calcification of <90° (Figure 1.2c). These coronary plaque characteristics associated with atherosclerotic vulnerability, inherent to IVUS imaging, offer potential advantages in the evaluation of coronary artery disease. Subsequently, IVUS has provided a valuable tool to study the vascular biology of coronary atherosclerosis in vivo.