第3代双源CT低剂量心脏一站式成像的可行性

摘要

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/(100ml·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 stressMPI 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.%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);l=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)mSv [MPI:(3.5±1.2)mSv,CCTA:(0.3±0.1)mSv].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.