Abstract 2752: Flat Panel CT versus 64 Detector Row CT for Characterization of Atherosclerotic Plaques
Purpose: Multidetector CT has not yet reached the capability of reliable distinction between lipid-rich and primarily fibrous atherosclerotic lesions - a pre-requisite for identification of most plaques prone to rupture. We compared a prototype flat panel CT (FPCT) scanner to 64 detector row CT (64-MDCT) for plaque characterization in an animal model of atherosclerosis.
Materials and methods: Eight Watanabe rabbits, prone to atherosclerosis, were used for this study. The rabbits were sedated and scanned by 64-MDCT during suspended mechanical ventilation without intravenous contrast at 0.625 mm slice thickness. Contrast agent (2 ml/kg) was administered through an ear vein and scanning repeated at 30, 60, and 90 seconds after injection. The rabbits were transferred to the FPCT where scanning was repeated with the same contrast administration protocol. FPCT images were reconstructed at voxel sizes down to 0.100 mm. The rabbits were sacrificed and the heart and aorta excised. The aorta was serially sectioned at 2–3 mm intervals from the left subclavian artery to the end of the specimen. The tissues were processed for light microscopy and sections stained with H&E and Movat pentachrome stain. MDCT and FPCT data were correlated with histologic sections for identification and localization of plaque components.
Results: MDCT and FPCT equally distinguished calcific deposits from soft plaque. FPCT identified more and smaller lipid pools, to about 1 mm. Only FPCT distinguished lipid pools from fibrous wall thickening and identified normal thickness wall. Histologic sections demonstrated calcific deposits and lipid pools which correlated with the tomographic imaging. Fibrous cap over the larger lipid pools could not be separately identified on either CT scanner.
Conclusion: FPCT provides resolution and contrast sensitivity sufficient to improve the distinction of atherosclerotic plaque components in an animal model with similar vessel size to that of human coronary arteries in comparison to MDCT. FPCT would be useful in longitudinal studies of plaque development and progression or response to therapy in an animal model.