MR Carotid Plaque Imaging and Contrast-Enhanced MR Angiography Identifies Lesions Associated with Recent Ipsilateral Thromboembolic Symptoms: An In Vivo Study at 3T

Transverse carotid plaque images and coronally acquired CE-MRA of the left carotid artery from an asymptomatic 61-year-old woman. A, Maximum intensity projection of the CE-MRA demonstrates a 74% stenosis at the left internal carotid artery. The horizontal line indicates the level of the transverse carotid plaque images (shown in B). B, Transverse image of a TOF angiogram demonstrates a smooth luminal surface and a dark juxtaluminal band indicating an intact thick fibrous cap. The thick fibrous cap is easier to appreciate as a high-intensity band (arrow) on the CE-T1WI and the T2WI. An isointense area on TOF images and T1WI, an iso- to low-intensity area on the T2WI, and a low-intensity area on the CE-T1WI image indicate a lipid-rich necrotic core without hemorrhage occupying 29% of the wall area (arrowhead). Notice that the lipid-rich necrotic core is easiest to appreciate on the CE-T1WI. Asymptomatic plaques tend to have a smaller lipid-rich necrotic core without hemorrhage as well as a thick fibrous cap.