Max Wintermark
Carotid atherosclerotic disease is considered to be responsible for 30% of all ischemic stroke. Luminal narrowing is the standard parameter used to report the severity of carotid atherosclerosis, and a luminal stenosis of ≥70% is typically considered a hallmark of increased stroke risk. However, even if they have a higher individual risk of developing a stroke, patients with ≥70% carotid stenosis represent fewer than 5% of patients. The majority of strokes occur in patients with <70% carotid stenosis, which represents a large proportion of the general population (70% in men and 60% in women 64 years or older). Better characterization of the risk of stroke in patients with <70% carotid stenosis could impact the criteria used to make treatment decisions in these patients, notably to refer them for stenting or endarterectomy, and could ultimately result in a decrease in the number of disabling strokes and related deaths in this group.
A number of carotid plaque morphologic features have been suggested as potential markers of the “vulnerable plaque” and are possibly associated with an increased risk of stroke. Carotid wall features have typically been studied using ultrasound and MRI. In the featured study, we used a 3D computerized interpretation of multidetector-row isotropic resolution CTA to assess, in a quantitatively accurate and standardized fashion, the histologic composition (including noncalcified components) and characteristics of carotid artery atherosclerotic plaques. We found a 72.6% agreement between CTA and histology for carotid plaque classification, perfect concordance for calcifications, and good correlation with histology for large lipid cores. CTA was also accurate in the detection of ulcerations. This study tells us that CTA can be used not only to assess luminal narrowing