Flat-panel versus 64-channel computed tomography for in vivo quantitative characterization of aortic atherosclerotic plaques

BackgroundFlat-panel computed tomography (FpCT) provides better spatial resolution than 64-channel CT (64-CT) and may improve in vivo quantitative assessment of atherosclerotic plaques.Methods and resultsLesions in 184 aortic histology sections from 6 Watanabe heritable hyperlipidemic rabbits were quantitatively compared with 64-CT (image thickness, 0.625 mm) and FpCT (image thickness, 0.150 mm) images. Images were re-oriented perpendicular to the vessel centerline. For detecting plaque, FpCT and 64-CT were not significantly different (sensitivity, 76% vs 66%; P = NS). Although FpCT was significantly more sensitive (42% vs 0%; P = < 0.001) for detecting eccentric lesions, the area under the curve (AUC) for FpCT (0.6) was not significantly different from that for 64-CT (0.45; P = NS). In detecting plaques with ≤ 10% lipid (low attenuation foci), FpCT was significantly more sensitive than 64-CT (24% vs 0.7%; P < 0.00) and had a significantly greater AUC (0.6 vs 0.5; P < 0.006). Additionally, FpCT was more sensitive (65% vs 0%; P < 0.00) in detecting plaques with ≤ 5% calcium (high attenuation foci) but not in detecting branch points. Both FpCT and histology allowed us to detect low-attenuation foci as small as 0.3 mm in diameter, whereas 64-CT allowed us to detect only low-attenuation foci ≥ 1.5 mm in diameter.ConclusionsFlat-panel CT seemed to have more potential for quantitatively screening low-risk small atherosclerotic lesions, whereas 64-CT was apparently more useful when imaging established, well-characterized lesions, particularly when measuring the vascular wall thickness in a rabbit model of atherosclerosis.