双源CT flash扫描模式在自由呼吸状态下肺动脉成像的可行性探讨

Feasibility of Dual-source CT Flash Scanning Mode in Pulmonary Artery Imaging under Free Breathing

目的总结双源光子CT flash扫描模式在自由呼吸状态下肺动脉成像的应用价值。方法对临床疑诊肺动脉栓塞的患者行CTPA检查,共发现59例肺动脉栓塞患者,其中28例患者(A组)采用了flash扫描方案,无需屏气,螺距3.2,扫描时间(0.64±0.11)s,造影剂流速5ml/s,造影剂用量(40±5)ml,采用对比剂跟踪触发技术,达阈值100HU后延迟3s自动扫描;31例患者(B组)采用屏气扫描方案,螺距1.2,扫描时间(1.67±0.20)s,造影剂流速5ml/s,造影剂用量(80±5)ml,对比剂跟踪触发达阈值100HU后延迟6s自动扫描;两组管电压均为120kv,Care Dose 4D打开;由两名放射科主任医师对图像进行评分,并测量7个肺血管CT值(HU),计算信号噪声比(SNR),比较辐射剂量、造影剂用量差异;使用统计软件对数据进行分析。结果A的图像质量均达优秀标准,B组多个病例有呼吸运动伪影而影响图像质量,而A组的辐射剂量及对比剂用量均低于B组。结论肺动脉造影使用Flash扫描模式能够获得满意的图像并降低了辐射剂量、造影剂用量、消除呼吸运动伪影。

Objective To summarize the application value of dual source photon CT Flash scanning mode in pulmonary artery imaging under free breathing condition. Methods The clinical data of patients with suspected pulmonary embolism, no contraindication of CTPA examination, found a total of 59 cases of pulmonary embolism patients, 28 patients(A group) using flash scanning scheme, without breath, pitch 3.2, scanning time was(0.64±0.11)s, contrast agent flow rate 5 ml/s, the amount of contrast agent(40±5)ml. By contrast trigger technology, tracking threshold 100 HU, threshold delay 3 S automatic scanning;31 patients(group B) using breath hold scanning scheme, pitch 1.2, scanning time was(1.67±0.20)s, contrast agent flow rate 5 ml/s, the amount of contrast agent(80±5)ml, by contrast trigger technology, tracking threshold 100 HU, threshold after a delay of 6 S automatic scanning;two sets of tube voltage for 120 kv, Care Dose 4 D opened;by two radiology physician on the image with 4 points method of subjective evaluation, and measurement of 7 pulmonary vascular CT value(HU), calculate the signal The ratio of noise(SNR) was compared, and the dosage of radiation and the dosage of contrast agent were compared, and the data were analyzed by using the statistical software. Results The image quality of A reached the best standard. B group had respiratory motion artifact affecting image quality, while the radiation dose and contrast dosage of group A were all lower than those of B group. Conclusion pulmonary angiography can obtain satisfactory images by using Flash scan mode and reduce the dose of radiation, the dosage of contrast agent, and eliminate the artifact of respiratory movement.