Feasibility of automatic spectral imaging protocol selection and adaptive statistical iterative reconstruction in reducing radiation and iodine contrast dose in abdominal CTA / 中国医学影像技术

ABSTRACT

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 Sixtyfour 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 im age 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.