320排CT前瞻性与回顾性心电门控一个心动周期内冠状动脉成像的对照研究

目的 比较前瞻性心电门控和回顾性心电门控320排CT在一个心动周期内冠状动脉成像的成功率、辐射剂量、成像质量和诊断结果,探讨低剂量前瞻性心电门控320排CT冠状动脉成像的可行性.方法 对本院临床拟诊冠心病、心率＜65次/min的500例病例依次分别采用了前瞻及回顾性心电门控冠状成像扫描方案,分为P组（前瞻组）和R组（回顾组）.根据Frank J的冠状动脉CTA图像质量评价标准,将冠状动脉CTA图像质量分为1分（不可评价）、2分（可接受）、3分（好）、4分（优秀）.评价两组成像的成功率、射线剂量、图像质量及诊断结果.结果 P组和R组检查成功率均为100%.P组和R组平均射线剂量为（3.28±1）mSv、（14.36±2.3）mSv,P组平均射线剂量较R组降低75.04%,差异有统计学意义（P＜0.01）.P组和R组各有3750（15×250）个冠脉节段,P组和R组冠脉节段管径太小（＜1.5 mm）难于评估分别占3.49%（131/3750）、3.78%（142/3750）,可评估占96.51%（3619/3750）、96.12%（3608/3750）,差异无统计学意义（P＞0.05）.P组和R组4分（优秀）图像分别为95.09%、95.23%,3分图像为1.09%、0.74%,2分图像为0.32%、0.24%,差异无统计学意义（P＞0.05）.两组2、3分图像均为运动伪影,无阶梯伪影及1分（不可评价）图像.P组的敏感性、特异性、阳性预测价值及阴性预测价值为86.49%、98.70%、88.89%、98.38%,R组的敏感性、特异性、阳性预测价值及阴性预测价值为83.87%.,98.74%,89.65%,97.93%,2组差异无统计学意义（P＞0.05）.结论 对于心率稳定在65次/min以下的患者,前瞻性心电门控320排CT冠状动脉成像可在一个心动周期内能以较低的辐射剂量达到回顾性心电门控的检查成功率、图像质量及诊断准确率,是切实可行的方法.

Comparison of prospective versus retrospective electrocardiogram-gating 320-detector computed tomography coronary angiography with sing heartbeat

Objective To compare the diagnostic performance of prospective electrocardiogram (ECG)-gating 320-detectorcomputed tomography coronary angiography (CTCA) versus retrospective ECG-gating CTCA. Methods 500consecutive patients suspected coronary artery disease with heart rate of less than 65 bpm were performed coronary computed tomography angiography (CCTA) with prospective (group P)and retrospective (group R) ECG gating in turn. The image quality was divided into four levels. Success rates, effective radiation dose,image quality and diagnosis were evaluated. Results Success rates of examination in group P and R are100%.Mean patient radiation dose was significantly different in group P (3.28±1mSv) and R(14.36 ±2.3 mSv).131 and 142 of 3750 segments (250 patients x 15 segments per patient) were too small(1.5mm)tobe characterized in group P and R. 96. 51% (3619/3750) and 96.12% (3608/3750) characterized segments were not significantly different in group P and R. 95.09% segments received a score of 4 and 1.09% segments received a score of 3 in group P, while 95.23% and 0.74% in group R.The cause of 2 and 3 points in the two groups was motion artifact. Stair-step artifacts and images scored as 1were not found.Compared with CAG,the sensitivity,specificity,false positive andfalse negative value in group P(86. 49% ,98. 70% ,88. 89% ,98.38%) and R(83. 87% ,98.74% ,89. 65%,97.93%) were not significantly different. Conclusion Although the patient radiation exposure was significantly lower, the diagnostic performance of prospective ECG-gating 320-detector CTCA was comparable with that of retrospective ECG-gating 320-detector CTCA on patients with stable heart rates less than 65 bpm.