The Model Appliance And Clinical Study Of IDose~4 Iterative Reconstruction On Double Dose Reduction With Head And Neck CTA

Objective: To evaluate the selection of i Dose4 iterative reconstruction and investigate the ability to detect double dose reduction in head and neck CTA using high level i Dose4.To evaluate the clinical application value of i Dose4 iterative reconstruction reducing radiation dose,iodine intake and controlling image quality in normal body mass index(BMI)patients with head and neck CTA.Methods: Model study: Eight neck vascular models with different concentration were established,and scanned with 100 k V tube voltage and 250 m As tube current using Philips Brilliance 256 scanner.The images were respectively reconstructed with i Dose4 3-5 and evaluated the quality of images.Then all the neck vascular models were scanned among any two of following conditions: tube voltage of 100 k V or 120 k V,tube current of 200 m As,250 m As,300 m As,350 m As.All the images were reconstructed with i Dose4-5.The CT values of vascular model were recorded and the relationship between CT value and concentration was analyzed.Clinical study: Fifty-two patients with normal body mass index(BMI)were referred for head and neck CTA,the patients were randomly assigned into groups: double-low group and routine group.The patients in the double-low group were scanned with 100 k V,reconstructed with i Dose4-5 and used 40 ml iodixanol(270 mg I/ml).Routine patients were scanned with 120 k V,reconstructed with FBP and used 50 ml iopamidol(370 mg I/ml).The general situation,image quality,radiation dose and average iodine intake were analyzed statistically.Result: Model study: There was no significant difference(P>0.05)in CNR(100 k V,250 m As)i Dose4-3,i Dose4-4,i Dose4-5 reconstructed images;However,i Dose4-5 reconstructed image SNR was significantly better than i Dose4-3 reconstruction,the difference was statistically significant(P<0.05).There was a positive correlation between iodine concentration and CT value of vascular model(100k V: r=0.997,P<0.01;120k V: r=0.993,P<0.01).Clinical study: Age,body weight,height and BMI of the two groups were not statistically significant(all P>0.05);The CT values of the common carotid artery,internal carotid artery,vertebral artery were lower than those of the routine group(all P<0.05);There were no significant differences in subjective score,SNR and CNR between the two groups(all P>0.05);The bilateral jugular vein pollution scores of the double-low group were higher than that of the routine group(all P<0.05);The radiation dose and mean iodine intake of both groups were lower than those of the routine group(all P <0.05).Conclusion: High-level iterative reconstruction can get better quality images.Low tube voltage can increase the CT value of target vessel.High-level iterative reconstruction techniques with double dose reduction in normal BMI patients undergoing head and neck CTA can not only achieve high-quality image images,but also reduce radiation dose and iodine intake significantly.