Comparative study on the effects of IMR algorithm and iDose4 algorithm on the image quality of low-dose left atrial pulmonary vein CT

DU Guoxiang; LIANG Zhimei; LI Min; LUO Yingyi; LU Bingfeng; LI Weixiong

doi:10.3969/j.issn.1674-3806.2024.10.14

Abstract：Objective To compare the effects of iterative model reconstruction(IMR)algorithm and hybrid iterative reconstruction(iDose4)algorithm on the image quality of low-dose left atrial pulmonary vein CT.Methods A total of 30 patients undergoing radiofrequency ablation due to atrial fibrillation in the Second Affiliated Hospital of Guangxi Medical University from January 2020 to December 2020 were recruited.The recruited patients received low-dose left atrial pulmonary vein CT examination with tube voltage of 80 kV and tube current of 350 mA.After scanning,the images were reconstructed by using IMR algorithm(IMR group)and iDose4 algorithm(iDose4 group),and the image quality in the two groups was subjectively scored.The region of interest(ROI)was delineated at the opening of the right superior pulmonary vein(RSPV),the right inferior pulmonary vein(RIPV),the left superior pulmonary vein(LSPV)and the left inferior pulmonary vein(LIPV),and the ROI was delineated for the left atrium,descending aorta and chest wall fat at the central level of the left atrium.The areas with uniform density in the ROI were selected and delineated,and the CT value and noise value[standard deviation(SD)value]in each ROI were recorded.The contrast-to-noise ratio(CNR)and signal-to-noise ratio(SNR)of the left atrium,RSPV,RIPV,LSPV and LIPV were calculated,and the objective scores were compared between the two groups.Results The subjective evaluations of the images in the IMR group and the iDose4 group by two radiologists were highly consistent,with intra-class correlation coefficient(ICC)being 0.895(P＜0.001)and 0.920(P＜0.001),respectively.The IMR group had significantly higher subjective scores of image quality than the iDose4 group[(4.50±0.57)points vs(3.86±0.68)points;t=3.898,P＜0.001].The image noise values(SD values)of the left atrium,RSPV,RIPV,LSPV and LIPV in the IMR group were lower than those in the iDose4 group,and the SNR and CNR in the IMR group were higher than those in the iDose4 group,and the differences were statistically significant(P＜0.05).The CT values of the left atrium,RSPV,RIPV,LSPV and LIPV in the IMR group were lower than those in the iDose4 group,and the differences were statistically significant(P＜0.05).Conclusion Compared with iDose4 algorithm,IMR algorithm can significantly reduce noise,improve SNR and CNR in low-dose left atrial pulmonary vein CT images,thereby improving the image quality.IMR algorithm is worth promoting in clinical application.