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Figure 5 Examples of four aortic specimens and corresponding MRI displays. (A to D) Movat’s pentachrome-stained samples. (E to H) Adjacent sections stained with anti-CD-68 (brown) to identify areas rich in macrophages and lipid. (I to L) Corresponding intravascular magnetic resonance imaging (MRI) displays. Arrows indicate the location of MRI interrogation. (A, E) Thick-cap fibroatheroma with the fibrous cap at the site of MRI measurement 120 µm in thickness (arrow). The CD-68 photomicrograph (E) reveals that an increased macrophage concentration is observed primarily in the deep layer. The corresponding MRI display (I) demonstrates the presence of lipid in the 100 to 250 µm deep layer (yellow), whereas the superficial 0 to 100 µm segment has a low lipid content, thus the MRI read-out is blue. (B, F) Ulcerated plaque; the interrogated necrotic core is near the surface (arrow). There are hemorrhagic areas within the necrotic core, and the corresponding CD-68–stained section (F) shows increased staining in the necrotic core. The corresponding MRI display indicates a high lipid content in both the superficial and deep bands (0 to 100 µm and 100 to 250 µm). (C, G) Normal aortic wall devoid of plaque. No anti-CD-68 staining is observed in panel G. The MRI interrogation (K) showed a high fibrous content and is devoid of lipid (blue) in both bands. (D, H) Thin-cap fibroatheroma (cap 50 µm in thickness) with the cap infiltrated by foam cells and a deeper necrotic core observed in the histologic section, as well as in the corresponding CD-68–stained section (H). The MRI display shows a high lipid content within both bands (L). Original magnification is x20. The 100-µm bar is for the MRI images, whereas the 250-µm bar is for the Movat’s and CD-68–stained sections.