Application of the Low-dose One-stop-shop Cardiac CT Protocol with Third-generation Dual-source CT

Objective To evaluate the feasibility of a low-dose one-stop-shop cardiac CT imaging protocol with third-generation dual-source CT (DSCT). Methods Totally 23 coronary artery disease (CAD) patients were prospectively enrolled between March to September in 2016. All patients underwent an ATP stress dynamic myocardial perfusion imaging (MPI) (data acquired prospectively ECG-triggered during end systole by table shuttle mode in 32 seconds) at 70 kV combined with prospectively ECG-triggered high-pitch coronary artery angiography (CCTA) on a third-generation DSCT system. Myocardial blood flow (MBF) was quantified and compared between perfusion normal and abnormal myocardial segments based on AHA-17-segment model. CCTA images were evaluated qualitatively based on SCCT-18-segment model and the effective dose(ED) was calculated. In patients with subsequent catheter coronary angiography (CCA) as reference,the diagnosis performance of MPI (for per-vessel ≥50% and ≥70% stenosis) and CCTA (for≥50% stenosis) were assessed. Results Of 23 patients who had completed the examination of ATP stress MPI plus CCTA,12 patients received follow-up CCA. At ATP stress MPI,77 segments (19.7%) in 13 patients (56.5%) had perfusion abnormalities. The MBF values of hypo-perfused myocardial segments decreased significantly compared with normal segments [(93±22)ml/(100 ml·min) vs. (147±27)ml/(100 ml·min);t=15.978,P=0.000]. At CCTA,93.9% (308/328) of the coronary segments had diagnostic image quality. With CCA as the reference standard,the per-vessel and per-segment sensitivity,specificity,and accuracy of CCTA for stenosis≥50% were 94.1%,93.5%,and 93.7% and 90.9%,97.8%,and 96.8%,and the per-vessel sensitivity,specificity and accuracy of ATP stress MPI for stenosis≥50% and ≥70% were 68.7%,100%,and 89.5% and 91.7%,100%,and 97.9%. The total ED of MPI and CCTA was (3.9±1.3) mSv [MPI:(3.5±1.2) mSv,CCTA:(0.3±0.1) mSv]. Conclusion The third-generation DSCT stress dynamic MPI at 70 kV combined with prospectively ECG-triggered high-pitch CCTA is a feasible and reliable tool for clinical diagnosis,with remarkably reduced radiation dose.