Objective:To evaluate the impacts of whole heart motion correction algorithm(snap-shot freeze 2.0,SSF2)on image quality and measuring consistency in contrast-enhanced cardiac com-puted tomography(CT)imaging for pre-TAVR aortic annulus CT evaluation.Methods:The CT data-sets of 57 patients(from 2020 Dec.to 2021 Aug.)with aortic valve diseases for pre-TAVR evaluation were retrospectively analyzed.All patients without control of heart rate were proceeded prospective ECG triggering contrast enhanced cardiac CT scan within a single beat.The images acquired at 35％and 75％R-R interval were both post-processed by coronary artery motion correction algorithm(snap-shot freeze 1.0,SSF1)and SSF2,thus four data sets(SSF1-35％,SSF1-75％,SSF2-35％,SSF2-75％)were obtained.The measurement of area,short/long axis,perimeter,mean diameter,left and right cor-onary height were performed by two independent radiologists blinded to the reconstruction informa-tion.The subjective evaluation on overall image quality was also conducted by them using 5-point Lik-ert score.CT values and SD values on aortic annulus,openings of left coronary and right coronary were measured,then signal to noise ratio(SNR)and contrast to noise ratio(CNR)were measured.Then the image quality and measuring consistency were compared.Results:SSF2 images had higher subjective scores than SSF1 images(P＜0.05)at both 35％and 75％R-R intervals,therein,for images acquired at 35％R-R interval,SSF2 improved the subjective image scoring from non-interpretable(＜3 points)to good(≥4 points).In terms of objective image quality,at 35％phase,SSF2 images had lower SD on aortic annulus,and at 75％phase,SSF2 images had higher SNR on opening of left coronary(both P＜0.05).For the specific radiologist,the measurements of aortic annulus were not statistically different between SSF1 and SSF2 images(all P＞0.05).As shown in consistency analysis,for images acquired at 35％R-R interval,SSF2 images resulted in narrower limit of agreement(LOA)in Bland-Altman results and higher interclass correlation coefficients(ICC)than SSF1 images when measuring the long axis,short axis,mean diameter,perimeter and area of aortic valve annulus,but there was no statistical difference.For 75％images,SSF2 also led to narrower LOA and higher ICC on measured mean diame-ter,area and the height of the left and right coronary arteries.Therein,for the measurement of the height of the left coronary artery,[SSF1-75％vs SSF2-75％,bias:-0.2246 vs.-0.3211,LOA:(-3.411,2.962)vs.(-2.034,1.392);ICC:0.892 vs.0.966,95％confidence interval:(0.824,0.935)vs.(0.943,0.98)],the consistency improvement by SSF2 was statistically significant.Conclusion:SSF2 could greatly reduce motion artifacts and improve the image quality of cardiac CT imaging,leading to higher consistency for the measurement of aortic annulus,which is valuable for the pre-TAVR evalua-tion of patients.
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