目的 总结双源光子CT单能大 螺距、低辐射剂量、低对比剂用量扫描 方案在主动脉夹层病变中的应用价值。 方法 对临床怀疑主动脉夹层病变的患 者行双源光子CT血管造影，随机使用大 螺距扫描方案及回顾性门控标准技术扫 描方案进行扫描。观察及分析胸腹主动 脉病变，有无夹层、夹层破口的位置及 数目等，对比这两种扫描方案的图像质 量、辐射剂量、对比剂用量差异。结 果 两种扫描方案得到的图像均可清晰 显示主动脉夹层的破口、内膜片、撕裂 范围、各主要功能血管的累及情况。A 组与B组扫描范围差异无显著性意义。 两组的重建及重组图像质量均达优化标 准。A组扫描时间约(1.37±0.19)s,B组 扫描时间约(14.23±2.01)s，A组辐射 剂量为(4.59±0.88)mSv，B组辐射剂量 为(15.95±0.99)mSv，A组造影剂用量为 (55±5)ml,B组造影剂用量为(85±5)ml, 两组差异有显著性意义。结论 双源光子 CT大螺距、低辐射剂量、低对比剂用量 扫描方案对主动脉夹层病变的检查及诊 断更具优势。

Objective To conclude the application value of dual-source single photons CT with low dose and low -dose contrast agent in chest aortic lesions. Methods Patients suspected aortic dissection in clinical are designed to do dual-source CT angiography, using big pitch scanning solutions or retrospective gating standard scanning technology to scan randomly. Then to observe and analyze the aortic disease in chest and abdomen,with or without dissection, the location and number of interlayer crevasse, the scope of tear, diaphragm, whether the main functional vascular are involved, with or without intramural hematoma, penetrating ulcer and aneurysm. At last, contrast the differences among the image quality, radiation dose and dosage of contrast agent of the two scanning modes. Results Both ways can show the location and number of interlayer crevasse, diaphragm,the scope of tear, whether the main functional vascular are involved. Group A and group B have no significant differences in scanning ranges. The image quality of reconstruction and reorganization of the two groups both reach the optimization criteria. Scanning time of group A is about (1.37±0.19)s, group B is about (14.23±2.01)s, Radiation dose of group A is (4.09±0.88)mSv, group B is (15.95±0.99) mSv. Dosage of contrast agent of group A is (55±5)ml, group B is (85±5)ml, So significant differences between the two groups can be seen. Conclusion The scanning scheme of Dual-source photons CT with big pitch, low radiation dose, and low contrast agent has more advantages in the chest aorta angiography examination.