Abstract 3637: Virtual Histology Using Intravascular Ultrasound In Assessment Of Intracranial Atherosclerotic Plaques: Correlation With Angiographic And Histopathological Findings
BACKGROUND Atherosclerotic plaque composition and structure varies in different patients and correlates with risk of plaque rupture and embolization. Virtual histology (VH)-intravascular ultrasonography (IVUS) is the modality of choice for in vivo imaging of the vessel wall of the coronary arteries.
OBJECTIVE To evaluate the correlation between VH-IVUS, angiographic, histopathological, and macroscopic findings in intracranial vessels.
METHODS Twelve different postmortem intracranial vessels; including middle cerebral artery, basilar artery, and anterior cerebral artery, were randomly selected. Contrast enhanced angiographic images were acquired. Then IVUS catheter (Eagle Eye Gold, 20 MHZ Digital, s5 Imaging System, Volcano Corp.) advanced within the arteries to obtain gray-scale and VH at regions of interest. The vessels were subsequently transected to obtain macroscopic images with Nikon Digital Camera DXM 1200C. The tissue was fixed, processed, and stained with hematoxylin and eosin staining. Finally, IVUS images were compared with angiographic, direct visualization, and histopatholical findings; regarding luminal stenosis, vessel wall thickness, and plaque content. Plaque content was categorized as: dark green, fibrous; yellow/green, fibrofatty; white, calcified; red, necrotic lipid core plaque on images.
RESULTS Out of 12 samples, 10 had atherosclerotic plaques in direct visualization. Angiographic stenosis was seen in 3 of these 10 arteries. Five arteries had outside protrusion of the plaque without any intraluminal stenosis. In the remaining 2 samples there was neither stenosis nor outer protrusion. Plaques were visualized in gray-scale IVUS as increased wall thickness, outer wall irregularity, protrusion, and/or hyperdense signal. The accuracy of IVUS to identify plaques was 100% compared with macroscopic visualization of the vessels. Fibrous and lipid deposition in the intima of the arterial wall seen in the histological sections was highly correlated (Pearson’s coefficient of 0.93) with VH-IVUS findings (Figure 1).
CONCLUSIONS These findings support new application of VH-IVUS in intracranial vessels especially with externally protruding angiographically negative plaques with the anticipated availability of smaller and more navigable IVUS catheters. Figure 1. A: a cross-sectional macroscopic view of anterior cerebral artery showing plaque within the vessel wall. B: Histological section of the vessel. C: VH-IVUS image from the same location.
- © 2012 by American Heart Association, Inc.