Predicting Carotid Plaque Characteristics Using Quantitative Color-Coded T1-Weighted MR Plaque Imaging: Correlation with Carotid Endarterectomy Specimens

MR imaging and histologic findings of the carotid plaques. A, D, G, T1-weighted images. B, E, H, Color-coded maps. C, F, I, Corresponding histologic specimens (left, Masson trichrome staining; right, antiglycophorin-A staining). A–C, Left carotid stenosis in a 70-year-old man. The plaque shows isointensity to adjacent muscle on the T1-weighted image (A, arrow) and is mainly green on the color-coded map (B, arrow), suggesting a fibrous composition. On histologic examination, the corresponding plaque specimens consist mainly of thick fibrous tissue (C and D). The percentage areas of the fibrous, lipid/necrotic, and hemorrhagic components are 97%, 3%, and 0%, respectively, on MR images and 85%, 15%, and 0%, respectively, in the histologic specimens. D–F, Right carotid stenosis in a 68-year-old man. The plaque shows slight hyperintensity on the T1-weighted image (D, arrow) and is mainly yellow on the color map (E, arrow), suggesting a lipid-rich plaque. The corresponding plaque specimens contained lipid and necrotic tissue that flowed out of the specimen during the tissue preparation (F). The percentage areas of the fibrous, lipid/necrotic, and hemorrhagic components are 35%, 64%, and 1%, respectively, on the MR images, and 33%, 66%, and 1%, respectively, in the corresponding specimens. G–I, Right carotid stenosis in a 74-year-old man. The plaque shows marked hyperintensity on the T1-weighted image (G, arrow) and red on the color map (H, arrow), suggesting intraplaque hemorrhage. In the corresponding pathology specimens, the plaque contains massive hemorrhage with a thin fibrous cap (I). The percentage areas of fibrous, lipid/necrotic, and hemorrhagic components are 17%, 13%, and 70%, respectively, on MR imaging, and 15%, 33%, and 52%, respectively, in the specimens. The fibrous cap thicknesses on the MR images (H, small arrows) and in the specimen (I, small arrows) are 0.47 and 0.39 mm, respectively. (C,F, and I, 3x magnification.)