Feasibility of coronary artery calcium scoring on virtual unenhanced images derived from single-source fast kVp-switching dual-energy coronary CT angiography

Abstract Background Dual-energy CT technology enables acquisition of virtual unenhanced (VUE) images from contrast-enhanced scans. Objective To assess the feasibility of coronary artery calcium (CAC) scoring on VUE images derived from fast kVp-switching dual-energy coronary CT angiography. Methods Twenty-seven patients underwent true noncontrast CAC-scoring CT followed by routine single-energy (120-kVp) and fast kVp-switching dual-energy coronary CT angiography, in a random acquisition order on the same day. We calculated the CAC scores on true noncontrast and VUE images. The image noises and the signal-to-noise and contrast-to-noise ratios of the aorta and coronary arteries were measured on both the single-energy coronary CT angiography images and dual-energy coronary CT angiography images (70 keV virtual monochromatic spectral images). The Pearson correlation coefficient test and paired t test were used for statistical analysis. Results Excellent correlation was observed between the CAC scores on the true noncontrast and those on the VUE images ( r  = 0.88; P P P Conclusions Excellent correlation was observed between the CAC scores on the VUE images and true noncontrast images. Thus, fast kVp-switching dual-energy coronary CT angiography could allow prediction of the true CAC scores, potentially reducing the total radiation exposure and image acquisition time by obviating the need for true noncontrast CAC-scoring CT.