自动协议选取能谱联合自适应迭代计算法重建技术降低腹部增强及血管成像辐射剂量及对比剂剂量的可行性

目的 探讨利用自动协议选取能谱（ASIS）扫描模式联合自适应迭代算法重建（ASiR）技术降低腹部增强及血管成像辐射剂量及对比剂剂量的可行性。方法 将64例接受腹部增强患者随机分为两组：试验组32例，采用ASIS扫描模式，应用30% ASiR和50% ASiR重建算法；对照组32例，采用120 kVp管电压，FBP重建。比较两组扫描方法辐射剂量及对比剂剂量；比较70 keV+30% ASiR图像与对照组动脉期及门静脉期肝脏及胰腺噪声、竖脊肌噪声（SMN）、肝脏CNR、胰腺CNR；对55 keV+50% ASiR图像与对照组动脉期腹主动脉及各主要分支血管CNR及门静脉期门静脉CNR以及血管图像主观评分进行统计学分析。结果 试验组动脉期及门静脉期的CTDIvol、DLP较对照组下降23.68%、23.57%和25.59%、18.45%，对比剂注射总量试验组较对照组减少16.86%。70 keV+30% ASiR动脉期及门静脉期肝脏、胰腺和竖脊肌的噪声均低于对照组（P均<0.05）。试验组55 keV+50% ASiR动脉期腹主动脉、肠系膜上动脉、腹腔干的CNR均高于对照组（P均<0.05）；静脉期门静脉的CNR和血管评分与对照组比较差异无统计学意义（P>0.05）。结论 采用ASIS扫描模式联合ASiR技术，70 keV+30% ASiR及55 keV+50% ASiR图像显示腹部脏器及腹部血管图像质量均优于传统120 kVp扫描模式的图像质量，且降低了辐射剂量及对比剂剂量。

Feasibility of automatic spectral imaging protocol selection and adaptive statistical iterative reconstruction in reducing radiation and iodine contrast dose in abdominal CTA

Objective To investigate the feasibility of automatic spectral imaging protocol selection (ASIS) and adaptive statiatical iterative reconstruction (ASiR) technique to reduce radiation dose and dose of contrast agent. Methods Sixty-four patients underwent routine abdominal examination were randomly divided into two groups. The test group used ASIS technique, with 30% ASiR and 50% ASiR reconstruction algorithm. The control group used 120 kVp tube voltage, FBP reconstruction method. The noise of liver, pancreas, sacrospinal muscle, CNR of liver and pancreas, subjective image score in arterial phase and portal venous phase were compared between the image of 70 keV+30% ASIR and control group. CNR of abdominal aorta and its branchs, CNR of portal vein, and subjective image score were statistically analyzed between image 55 keV+50% ASiR and control group in the arterial phase and portal venous phase. Results Compared with control group, CT dose index volume for arterial phase and portal venous phase in test group decreased by 23.68%, 23.57% and dose length product decreased by 25.61%, 18.45%, total contrast injection decreased 16.86%, the noise of liver, pancreas and sacrospinal muscle in 70 keV+30% ASiR were lower than those of control group in abdominal arterial and portal phase (all P<0.05). CNR of abdominal aorta, superior mesenteric artery, celiac axis and score in 55 keV+50% ASiR were higher than those of control group in abdominal arterial phase (all P<0.05), CNR of portal vein and score in portal phase had no statistically difference (all P>0.05). Conclusion Combining of ASIS and ASiR including 70 keV+30% ASiR and 55 keV+50% ASiR, images are superior to that of the conventional 120 kVp+FBP scan mode for abdominal CT image and vessel image quality, which can reduce the radiation dose and the dose of contrast agent.