目的 探讨128层CT前门控低剂 量扫描在小儿复杂先天性心脏病(CHD) 的临床应用。方法 收集行128层CT前门 控低剂量扫描技术检查的先心病患儿35 例，记录其容积CT剂量指数(CTDIvol)和 剂量长度乘积(DLP)，计算出有效辐射 剂量(ED)。比较128层CT前门控与心脏 超声心电图(UCG)结果的符合率，采用 χ2检验，以P＜0.05为差异有统计学意 义。结果 35例前门控低剂量扫描的容 积CT剂量指数为(0.90±0.24)mGy；剂 量长度乘积为(12.9±4.7)mGy·cm；有 效辐射剂量是(0.29±0.09)mSv，最低 0.156mSv，最高0.52mSv。图像质量评分 为(4.3±0.7)，图像均符合诊断要求。 128层CT前门控的诊断准确率明显优于 超声心电图(UCG)，诊断准确率分别为 97.2%(104/107)、90.6%(97/107)，差异 有统计学意义(χ2=4.013,P＜0.05)。其 中心内畸形准确率分别为98.2%(57/58) 和96.6%(56/58)，差异无统计学意义 (χ2=0.342,P＞0.05),心脏-大血管连 接异常诊断准确率均为100.0%(24/24), 心外大血管畸形诊断准确率分别为 92.0%(23/25)和68.0%(17/25)，差异有 统计学意义(χ2=4.500,P＜0.05)，明显 优于UCG。同时，MSCT能观察患儿肺部情 况，共检出合并气道异常3例。结论 128 层CT前门控低剂量扫描在小儿复杂性先天 性心脏病诊断中具有重要的临床价值，显 著降低辐射剂量。

Objective To evaluate the low-dose prospective ECG-gated 128-slice spiral CT angiography in the diagnosis of complex congenital heart disease in children. Methods Thirty-five children with congenital heart disease received low-dose prospective ECGgated 128-slice spiral CT angiography, The CT dose index volume(CTDIvol) and dose length product(DLP) were recorded in order to calculate effective(ED). Diagnosis and overall image quality were assessed by two experienced radiologists by using a five point scale independently. The surgical results were taken as the diagnostic standards, and the CT angiography data were compared with UCG results using χ2 test. Results The CTDIvol was(0.90±0.24)mGy. The DLP was (12.9±4.7)mGy·cm. The ED was (0.29±0.09)mSv with a range of 0.156 mSv to 0.52 mSv. The average subjective image quality score was (4.3±0.7). All images were diagnosable. The definitive diagnosis of extracardiac vascular anomalies was made in 97.2%(104/107) of patients by using 128-slice spiral CT angiography, which were significantly superior to UCG results[90.6%(97/107)] (χ2=4.013,P＜0.05). In the cardiac malformations, the definitive diagnosis by 128-slice spiral CT angiography was 98.2%(57/58) and there was no significant difference between 128-slice spiral CT angiography results and UCG results [96.6%(56/58)](χ2=0.342,P ＞0.05). The definitive diagnosis of the cardiac/large-vessel malformations was made in 100％(24/24) of the patients by both 128-slice spiral CT and UCG. The definitive diagnosis of extracardiac vascular anomalies was made in 92.0%(23/25) of patients by using 128-slice spiral CT angiography, which were significantly superior to UCG results[68.0%(17/25)](χ2=4.500, P＜0.05). In addition, 128-slice spiral CT angiography detected airway abnormality in 3 cases. Conclusion The low-dose prospective ECGgated 128-slice spiral CT angiography exhibits great application value in the diagnosis of complex congenital heartdisease, which significantly reduce the radiation dose．