Assessment Of Correlation Between Anatomic Information Of Plaque With Calcification And Coronary Computed Tomography Angiography-based Fractional Flow Reserve

Objectives To explore the effect of morphologic indices and geometry configurations on coronary computed tomography angiography-based fractional flow reserve(CT-FFR)by quantifying the atherosclerotic plaque with calcification composition,and assess the diagnostic performance of CT-FFR for coronary artery disease(CAD)with the reference of single photon emission computed tomography-myocardial perfusion imaging(SPECT-MPI).Methods A total of 267 patients clinical implicated CAD underwent coronary computed tomography angiography(CCTA)were retrospectively analyzed.Morphologic indices and geometry configurations of plaque with calcification were automatically extracted using semi-automatic plaque quantified analysis software.Morphology of the calcification shape was categorized into spotty calcification,nodule calcification,and strip-bulk calcification according to the maximal section area and length,and scored.The position of plaque in terms of coronary vessels and segments was determined for all lesion with calcification.Eccentric index(EI),the value of Poiseuille’s equation(the ratio of lesion length to the fourth power of minimal lumen diameter,LL/MLD4),the ratio of impaired lumen volume and volume to myocardial mass of lesion coronary segment were calculated,respectively.CCTA data setting was split into two groups defined as normal coronary hemodynamics(CT-FFR>0.8)and lesion specific ischemia(CT-FFR≤0.8)at the level of individual plaque,respectively.Bivariate correlation analysis was used for the correlation of anatomic quantified-information of plaque with calcification with CT-FFR measurements.Independent-samples T test or Mann-Whitney U test was performed for the difference of anatomic quantified values of plaque with calcification between two groups(CT-FFR>0.8 and CT-FFR≤0.8).Bland-Altman test was executed for the consistency of CT-FFR measurements obtained at two different time points,and based on different reconstruction kernels(FC43 and FC05).Multiple logistic regression analysis was used to explore the quantified indices of plaque with calcification to predominantly impact on CT-FFR.CT-FFR was converted into binary data,and then was test by using the continuity corrected McNemar test to assess the diagnostic performance of CT-FFR and SPECT-MPI.With the reference of SPECT-MPI,diagnostic sensitivity,specificity,negative predictive value,positive predictive value and accuracy to identify lesion specific ischemia were calculated at the level of per patient.Results ①Morphological indices and geometric configurations including Agatston score,gross scores of all calcification,accumulated scores of nodule and strip-bulk shape calcification,aggregate volume and burden of plaque,volume and percent of calcification and non-calcification,percent of maximal diameter stenoses and area stenoses,lesion length,eccentric index,LL/MLD4,tortuosity,the ratio of impaired lumen volume and volume to myocardial mass of lesion coronary segment were negatively associated with the measurements of CT-FFR(r=-0.340,-0.267,-0.249,-0.256,-0.256,-0.289,-0.150,-0.199,-0.183,-0.238,-0.185,-0.272,-0.218,-0.446,-0.157,-0.258,-0.185,P=0.000,0.000,0.000,0.000,0.000,0.000,0.004,0.000,0.005,0.000,0.000,0.000,0.000,0.000,0.000,0.000,0.000).However,remodeling index was not significantly correlated with CT-FFR measurements(r=-0.066,P=0.196).②Agatston score,gross scores of all calcification,accumulated scores of nodule and strip-bulk shape calcification,aggregate volume and burden of plaque,volume and percent of calcification,volume of non-calcification,percent of maximal diameter stenoses and area stenoses,lesion length,eccentric index,LL/MLD4,tortuosity,the ratio of volume to myocardial mass of lesion coronary segment and the percent of lesion position located at the proximal and medial segment in the group of lesion specific ischemia were all significantly greater than those in the group of normal coronary hemodynamics(P=0.000,0.000,0.000,0.000,0.000,0.000,0.000,0.001,0.000,0.000,0.000,0.000,0.000,0.000,0.000,0.000,0.003,0.038).The ratio of non-calcification and the ratio of impaired volume in the group of lesion specific ischemia were significantly smaller than those in the group of normal coronary hemodynamics(P=0.001).However,no statistically significances between two groups were found with respective to the percent of lesion position located at the left anterior descending branch and the values of remodeling index(P=0.133,0.396).③The lesion position located at the middle segment of coronary vessels(OR=25.319,95%CI:4.347～147.470),eccentric index(OR=6.493,95%CI:1.457～28.928),lesion length(OR=1.104,95%CI:1.047～1.165),Agatston score(OR=1.005,95%CI:1.002～1.007)and aggregate volume of plaque(OR=0.994,95%CI:0.990～0.999)were the predominant factors of lesion specific ischemia of plaque with calcification.④The averaged differences of CT-FFR measurements obtained at different time points were-0.001(-0.045～0.044)and-0.001(-0.022～0.025)based on images with reconstruction kernel of FC 43 and FC05,respectively.The averaged difference between the CT-FFR measurements of the images reconstructed with both FC43 and FC05 was 0.002(-0.106～0.110).There was no statistically significance between diagnostic performance of CT-FFR and SPECT-MPI to identify CAD(P=0.564).With the reference of SPECT-MPI,the diagnostic sensitivity,specificity,negative predictive value,positive predictive value and accuracy were 80.00%,85.00%,94.44%,57.14%and 84.00%in a per-patient basis for the whole cohort underwent CT-FFR measuring and SPECT-MPI,respectively.Conclusions ①Agatston score,gross scores of all calcification,accumulated scores of nodule and strip-bulk shape calcification,volume and percent of calcification,percent of maximal diameter stenoses and area stenoses,lesion length,eccentric index,LL/MLD4,tortuosity,the ratio of impaired lumen volume and volume to myocardial mass of lesion coronary segment were negatively associated with CT-FFR measurements,except for remodeling index.②Lesion position located at the middle segment of coronary vessels,eccentric index,lesion length,Agatston score and aggregate volume of plaque were the predominant factors of lesion specific ischemia of plaque with calcification.However,calcification shape incorporating maximal section area and length revealed nonsignificant effect on lesion specific ischemia correlated with plaque with calcification.③The measurements of domestic CT-FFR software showed excellent reproducibility in terms of different time points and reconstruction algorithm,and provided reliable diagnostic performance to identify CAD in a per-patient basis compared with SPECT-MPI.