Atherogenesis is an inflammatory process that begins in childhood. Early detection of atherosclerosis might allow for selection of subjects at risk for future cerebrovascular events at a time when dietary and lifestyle modification may have its greatest impact, and medical intervention may be useful for those who are refractory to such treatment or who are at greater risk for an event. Early detection relies on a knowledge of the distribution of atheroma formation, which can be predicted by understanding the hemodynamic patterns of blood flow. Early formation is accompanied by a vascular remodeling that normalizes the area of the vessel lumen, making early detection impossible by angiography. Elevated serologic markers of inflammation may be used as evidence of formation of atherosclerosis, but inflammatory markers lack sensitivity and specificity. Preliminary evidence supports the ability of MRI to detect early atheroma formation, possibly even before substantial wall thickening occurs. Once atheroma has formed with measurable stenosis, the goal of imaging studies is to predict stroke risk and determine the need for surgical intervention. Subjects with symptomatic high-grade carotid stenosis have been shown to benefit from surgery with a reduced stroke risk when compared with medical management alone, although controversy exists regarding the management of moderate symptomatic carotid stenosis or asymptomatic carotid disease. In these individuals, understanding atheroma morphology may prove to be of greater utility for assessing stroke risk and determining the appropriate management. Morphologic characterization may also be helpful in monitoring the effect of medical intervention. MRI has proven capable of characterizing the morphologic composition of carotid atheroma, although the clinical implications continue to be investigated.