心电门控冠状动脉成像的临床应用

目的 比较320排CT前瞻性和回顾性心电门控冠状动脉成像的检查成功率、辐射剂量、成像质量及诊断结果,探讨320排CT前瞻性心电门控CT冠状动脉成像临床应用的可行性.方法 分别对2009年6至12月中山大学附属第三医院心率稳定＜65次/min的480例患者进行前瞻性和回顾性心电门控冠状动脉成像,分为前瞻组和回顾组各240例.采用最大密度投影(MIP)、曲面重组(CPR)及容积再现(VR)等多种重组技术显示冠状动脉.根据有无运动及阶梯伪影等将图像质量分为优、良、差,计算两组的平均有效辐射剂量,与DSA对比计算CT冠状动脉成像的诊断结果,并进行统计学分析.结果 前瞻组和回顾组的检查成功率均为100%.前瞻组平均有效辐射剂量为(3.3±1. 3)mSv,明显低于回顾组的(13.0±1.6)mSv(P＜0.01).前瞻组诊断性冠状动脉节段和非诊断性冠状动脉节段为95.42%(3435/3600)、4.58%(165/3600),与回顾组的95.81%(3449/3600)、4.19%(151/3600)比较,差异无统计学意义(P＞0.05).前瞻组的敏感性、特异性、阳性预测值及阴性预测值为93.22%、99.21%、91.64%、99.05%,回顾组的敏感性、特异性、阳性预测值及阴性预测值为94.55%、98.80%、95.86%、98.54%,两组差异无统计学意义(P＞0.05).结论 对于心率稳定＜65次/min的患者,320排CT前瞻性心电门控冠状动脉成像明显降低辐射剂量,但与回顾性心电门控冠状动脉成像的检查成功率、图像质量及诊断结果差异无统计学意义,是切实可行的方法.

Clinical application of prospective electrocardiogram-gated 320-detector computed tomography coronary angiography

Objective To compare the success rate, radiation dose, image quality and diagnosis of prospective electrocardiogram (ECG)-gated 320-detector computed tomography coronary angiography (CTCA) versus retrospective ECG-gated CTCA. Methods Patients suspected coronary artery disease were divided into two groups which underwent 320-detector CTCA with prospective ECG-gated and retrospective ECG-gated scanning ( n = 240 each, HR ＜ 65 bpm ). Curved-planar reconstruction ( CPR ), maximum intensity projection (MIP) and volume rendering (VR) were performed to demonstrate the coronary arteries. The image quality was defined as excellent,good and poor by motion and stair-step artifacts. Effective radiation exposure dose was estimated from the dose-length product. Effective radiation dose, image quality and diagnosis were evaluated. Results The success rate of examination was 100% in prospective ECG-gated group and retrospective ECG-gated group. The mean effective radiation dose of prospective ECG-gated CTCA ( 3.3 ± 1.3) mSv] was significantly lower than that of retrospective ECG-gated CTCA ( 13.0 ± 1.6) mSv,P ＜ 0. 01]. Segments of diagnostic image quality ( 95.42%, 3435/3600 ) and non-diagnostic coronary segments (4. 58%, 165/3600) in prospective ECG-gated group were similar as those of retrospective ECG-gated group (95.81%,3449/3600 and 4. 19%, 151/3600, all P ＞0.05). Compared with CAG, the sensitivity, specificity, false positive and false negative value in prospective ECG-gated group (93. 22%,99. 21%, 91.64%, 99.05% ) and retrospective ECG-gated group ( 94. 55%, 98. 80%, 95. 86%,98.54% ) were not significantly different. Conclusion Though the effective radiation dose is significantly lower, the success rate, image quality and diagnosis of prospective ECG-gated 320-detector CTCA is comparable with that of retrospective ECG-gated 320-detector CTCA on patients with stable heart rates less than 65 bpm.