Prognosis Study And Morphological Evaluation Of Multi-slice Computed Tomography In Congenital Heart Disease Patients With Pulmonary Atresia With Ventricular Septal Defect

Purpose1.To compare the image quality between filtered back projection(FBP)reconstruction algorithm and iterative model reconstruction(IMR)algorithm in infants with congenital heart disease(CHD).2.To assess the predictive value of preoperative cardiac computed tomography angiography(CTA)for survival in patients with pulmonary atresia with ventricular septal defect and major aortopulmonary collateral arteries(PA-VSD-MAPCAs).3.To assess the frequency and imaging anatomy of retro-oesophageal aortopulmonary collateral arteries(REMs)in PA-VSD-MAPCAs patients.Materials and Methods1.Fifty-one infants with CHD who underwent cardiac computed tomography in our institution were prospectively included.Images were obtained using a 256-slice multi-detector CT with a tube voltage of 80 kV.The effective radiation doses were calculated.Imaging data were reconstructed using the FBP and IMR algorithms.Parameters of objective image quality(noise,signal-to-noise ratio(SNR)and contrast-to-noise ratio(CNR));subjective image quality(overall image quality,image noise and margin sharpness);segments of coronary artery visualization;and diagnostic accuracy for the two algorithms were measured and compared.2.We retrospectively analysed PA-VSD-MAPCA patients with preoperative CT who underwent right ventricular outflow tract reconstruction and MAPCA unifocalization(n = 24)or right ventricular outflow tract reconstruction and pulmonary artery rehabilitation(n = 28).CT parameters including:McGoon ratio,total neopulmonary artery tndex(TNPAI),pulmonary vein index(PVI),the absence or presence of native pulmonary artery(NPA)and the number of bronchopulmonary segments supplied by native pulmonary arteries(BSSNPAs).The end-point was overall survival.Prognostic values of CTA were assessed using Cox univariate and multivariate analyses.The significant threshold of independent CTA parameters was calculated using receiver-operating characteristic(ROC)curves.3.A total of 130 consecutive PA-VSD-MAPCA patients with preoperative CT data who underwent cardiac surgery were included.Detailed analyses of the MAPCA anatomical variables were including:the total number of MAPCAs relative to the bilateral lungs;MAPCA origin(the height of the origin site of the MAPCAs;the angle of the origin site of the MAPCAs);the presence or absence of a retro-oesophageal course for the MAPCAs;the relationship between the MAPCAs and the bronchus at the pulmonary hilum;stenosis of MAPCAs;the side of the aortic arch and the disease classification.Results1.The mean effective radiation dose was 0.61 ± 0.32 mSv.Compared to FBP,IMR yielded significantly lower noise(P<0.01),higher SNR(P<0.01)and CNR(P<0.01)values,and a greater subjective image quality score(overall image quality,image noise and margin sharpness)(all P<0.01).The total number of coronary segments visualized was significantly higher for IMR than for FBP(P = 0.01).There was no significant difference in the diagnostic accuracy between the FBP and IMR algorithms(?2 = 0.08,P = 0.78).2.During a median follow-up of 1145 days,a total of 13 deaths were observed.Multivariate analysis identified a high pulmonary vein index(PVI)[hazard ratio(HR)= 0.03;95%confidence interval(CI):0.03,0.28;P<0.01]and the presence of native pulmonary artery(HR = 0.06;95%CI:0.10,0.35;P<0.01)as independent positive predictors of better survival.The area under the ROC curve for PVI was 0.79(P<0.01),and a cut-off point of 438 mm2/m2 was deemed the significant threshold for survival(sensitivity 92%,specificity 72%).3.A REM was identified in 82/130 included patients(63%).A total of 277 MAPCAs were observed in these 82 patients and were divided into groups based on REM status:REM(n = 94)and non-REM(n = 183).Compared with non-REMs,REMs originated at a lower level(P<0.01)and tended to originate from the lateral side of the aorta(P<0.01).REMs had a higher probability of suffering stenosis(?2 = 9.79,P<0.01),particularly midsegment stenosis(?2=6.27,P = 0.01).Relative to the bronchus,REMs were more commonly located posterior to the bronchus at the pulmonary hilum than non-REMs(91%of REMs were located posterior to the bronchus compared with 51%of non-REMs)(?2=50.81,P<0.01).Conclusions1.For infants with CHD undergoing cardiac CTA,the IMR reconstruction algorithm provided significantly increased objective and subjective image quality compared with the FBP algorithm with accessible radiation.However,IMR did not improve the diagnostic accuracy compared with FBP.2.Preoperational high PVI and native pulmonary artery presence were significant morphologic predictors of a positive survival advantage in PA-VSD-MAPCA patients.A PVI ? 438 mm2/m2 may be a reliable positive prognosticator that could improve the decision-making strategy for PA-VSD-MAPCA patients.3.The unique CTA data obtained in this study showing the anatomy of REMs will be highly useful for surgeons in identifying REMs during unifocalization procedure.