Application Study On Myocardial Perfusion Imaging With Spectral CT

ObjectiveTo explore the optimum match of monochromatic energy level and adaptive statistical reconstruction (ASiR) for monochromatic reconstruction of myocardial CT perfusion (CTP) images with dual-energy CT.Materials and MethodsThirty subjects with suspected coronary artery disease (CAD) were scanned on spectral CT. Conventional polychromatic images and 10 sets of monochromatic images (60,65,70,75,80,90,100,110,120, and 130 kiloelectron volts [keV]; each with increasing contributions of ASiR, ie,0%,20%,40%,60%,80%) were obtained from a single gemstone spectral imaging (GSI) acquisition. The background noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and beam-hardening artifacts (BHA) of the specific myocardial segment in monochromatic images were assessed by ANOVA test and were compared with conventional polychromatic groups.ResultsMonochromatic reconstructions and ASiR all had potential to improve image quality in this lower radiation dose scan and had their own specific rules to follow. With the increase of monochromatic energy imaging noise and BHA decreased. Adding 40%or more ASiR contributed to the reduction of the noise, while for BHA this seemed ambiguous. Compared with conventional polychromatic images, reconstructions with 75keV showed the highest improvement in SNR (48%; P＜0.001; combined with 80% ASiR) and CNR (35%; P＜0.001; combined with 60% ASiR).ConclusionMonochromatic reconstruction at 70-75keV combined with 40% ASiR can offer satisfactory reduction of noise and BHA, meanwhile obtains superior SNR and CNR in this myocardial CTP scan with spectral CT.