Although atherosclerosis often leads to lumen narrowing and symptomatic cardiovascular disease, it is now recognized that arteries have the potential to compensate by enlarging in response to atherosclerosis. We tested the hypotheses that carotid arterial interadventitial (IA) and lumen diameters were related to wall thickness and that carotid arterial diameters of individuals with coronary artery disease (CAD) differed from those of CAD-free controls.