第3代双源CT低剂量心脏一站式成像的可行性

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

目的评估第3代双源CT低剂量心脏一站式成像的可行性。方法 2016年3月至9月在北京协和医院就诊的冠心病患者23例,采用第3代双源CT行ATP负荷70 kV动态心肌灌注成像(MPI)(前瞻性心电触发摇篮床扫描模式,收缩末期采集,扫描时间32 s)联合前瞻性心电触发大螺距扫描冠状动脉血管成像(CCTA)。基于AHA-17段模型,定量计算ATP负荷下心肌血流量(MBF),比较血流灌注正常及异常节段MBF值;基于SCCT-18段模型评价CCTA图像质量,计算CT检查有效剂量(ED)。以后续介入冠状动脉造影(CCA)为参照,分析CCTA(对CCA≥50%狭窄)及MPI(分别对CCA≥50%及≥70%狭窄)的诊断准确性。结果 23例行ATP负荷MPI联合CCTA检查的患者中,有12例行后续CCA检查。ATP负荷MPI中,共13例(56.5%)患者的77个(19.7%)心肌节段有血流灌注缺损,其MBF值明显低于血流灌注正常心肌节段[(93±22)ml/(100 ml·min)比(147±27)ml/(100 ml·min);t=15.978,P=0.000]。CCTA检查中,93.9%(308/328)的冠状动脉节段图像可用于诊断。分别以冠状动脉血管及节段为单位评价,CCTA对CCA中≥50%狭窄病变的诊断敏感性、特异性和准确性分别为94.1%、93.5%和93.7%及90.9%、97.8%、96.8%;ATP负荷MPI对CCA中单支血管≥50%及≥70%狭窄的诊断敏感性、特异性和准确性分别为68.7%、100%和89.5%及91.7%、100%和97.9%。MPI联合CCTA一站式扫描的总ED为(3.9±1.3)m Sv[MPI:(3.5±1.2)m Sv,CCTA:(0.3±0.1)m Sv]。结论第3代双源CT下ATP负荷70 kV动态MPI联合前瞻性大螺距CCTA扫描方案具有临床可行性和诊断可靠性,并可显著降低检查辐射剂量。

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） pa-tients 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 %, and93. 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 %, and97. 9 %. The total ED of MPI and CCTA was（ 3. 9 ± 1. 3） m Sv [MPI：（ 3. 5 ± 1. 2） m Sv, CCTA：（ 0. 3 ±0. 1） m Sv]. 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.