Application of non-linear blending technique in abdominal aortic angiography involving novel injection protocol with reduced contrast medium dose and low flow rate

Abstract:

Objective：To investigate the feasibility of enhancing image quality of abdominal aorta Computed Tomography Angiography （CTA） under low contrast agent and individualized injection of low injection rate with non-linear blending（NLB） of third-generation dual-resource CT device. Methods：A total of 30 patients who were likely to undergo dual-energy abdominal aorta CTA were enrolled. The third-generation dual-source CT device with a tube voltage at 70/sn150 kVp combined with intelligent tube current adjustment technology of CARE Dose 4D was used. The dose of contrast medium was obtained in accordance with patients’ weight plus 0.5，and then the injection velocity was defined by contrast agent/examining time（scanning time + delay time after achieving the trigger threshold value）. NLB image and regular linear blending（LB） with a fusion coefficient of 0.5 were re-constructed. Images’ CT values，signal to noise ratio（SNR） and contrast to noise ratio（CNR） on abdominal aorta and initial part of its main branches in two groups were evaluated by using paired t-test. Subjective quality score of images in two group was compared via Mann-Whitney U test and consistency of the score was analyzed by Kappa test. Results：The average effective radiation dose was （4.80±0.77） mSv，the average iodine intake was （12.30±1.71） g，the average contrast volume was （35.3±4.91） mL，and the average injection velocity was （3.30±0.47） mL/s. Vascular CT value，SNR and CNR in the NLB group were significantly increased than those in LB group（P<0.05）. Average CT value and SD value of muscles at the back of chest in two groups had no statistically significant difference（P>0.05）. Subjective score of images in two groups had good consistency（?资=0.618，P<0.05），and it in the NLB group was higher than that in the LB group，with an improvement of 0.55（P<0.05）. Conclusion：NLB of third-generation dual-source CT device under low contrast agent and individualized injection of low injec－tion rate can significantly improve the image quality of abdominal aorta CTA.