Measurement of carotid intima-media thickness to assess progression and regression of atherosclerosis

Atherosclerosis can remain below the clinical horizon for a long time. Acute vascular disease, however, can manifest clinically at almost any stage. Brightness ultrasonographic imaging of the carotid arterial walls can depict all stages of atherosclerotic arterial wall changes as a continuous variable. Here de Groot et al . describe the role of carotid IMT measurements as a tool in risk evaluation of individuals and explore how this technique could advance atherosclerosis research. Imaging modalities have been developed to assess atherosclerosis in vivo in the arterial wall because large clinical end-point studies are time-consuming and costly. Historically, in-hospital angiography and Doppler ultrasonography have been used to assess atherosclerosis development. Investigations of the arterial lumen are, however, increasingly being replaced by modalities that can measure changes in the arterial wall itself—intravascular ultrasonography, MRI and multislice CT. The fact that intravascular ultrasonography is invasive, CT involves substantial radiation exposure and requires contrast agents, and that MRI is time-consuming and technically challenging all limit the widespread use of these techniques. Moreover, all modalities have high associated costs. B-mode ultrasonographic imaging of the carotid arterial walls occupies a unique position in atherosclerosis research. This method enables sensitive, reproducible and noninvasive assessment of intima–media thickness (IMT) as a continuous variable. Epidemiological and clinical trial evidence as well as digitization and standardization have made carotid IMT a validated and accepted marker for generalized atherosclerosis burden and vascular disease risk. Here we describe the application of carotid IMT measurements as a tool in risk evaluation of individuals and in studies of atherosclerosis progression and regression. Key Points In atherosclerosis research, surrogate markers are important in the early identification of disease, in risk assessment and the evaluation of drug efficacy If imaging modalities are to be used in clinical studies and pharmaceutical trials, technical optimization and stringent standardization are required Carotid ultrasonography is a noninvasive method for measuring carotid intima–media thickness–a validated surrogate marker of atherosclerotic disease—that allows atherosclerosis assessment in individuals across the entire cardiovascular risk spectrum Carotid intima—media thickness measurements ca