Application Of CT-based 3D Reconstruction And 3d Printing Technology In Children With Congenital Heart Disease

Part 1 Clinical value of CT in diagnosis of pediatric complex congenital heart diseaseObjective: To investigate the clinical value of CT compared with transthoracic echocardiography in diagnosis of complex congenital heart disease in children.Methods: From November 2017 to June 2018,127 children diagnosed with complex congenital heart disease were retrospectively included in this study,among which there were 75 males and 52 females.All of the children underwent CT and transthoracic 2Dechocardiography examination before operations.The diagnoses were divided into intracardiac malformation,heart and great vessel connection malformation and extracardiac malformation.Sensitivity,specificity,positive predictive value and negative predictive value of CT and transthoracic echocardiography were calculated and compared.Results: The age of these 127 children was ranged from 3 days to 24 months,with an average of 6.3 ± 6.2 months,weight was ranged from 2.8 to 12.5 kg,with an average of 6.6 ± 2.8 kg.Totally 409 malformations were confirmed after surgery,among which there were 174 intracardiac malformations,62 heart and great vessel connection malformations and 173 extracardiac malformations.In CT examination results,168 intracardiac malformations were detected,missed diagnosis and misdiagnosis were 6/4,60 heart and great vessel malformations were detected,missed diagnosis and misdiagnosis were 2/0,166 extracardiac malformations were detected,missed diagnosis and misdiagnosis were 7/1.In echocardiographic examination results,172 intracardiac malformations were detected,missed diagnosis and misdiagnosis were 2/0,59 heart and great vessel malformations were detected,missed diagnosis and misdiagnosis were 3/0,147 extracardiac malformations were detected,missed diagnosis and misdiagnosis were 26/0.The overall sensitivity,specificity,positive predictive value,negative predictive value of CT and echocardiography were 96.3%,99.8%,98.7%,99.5% and 92.4%,100%,100%,98.9% respectively.Overall sensitivity of CT was higher than that of echocardiography 96.3% vs.92.4%,the difference was statistically significant(?2=7.03,P<0.05).In the diagnosis of extracardiac malformation,the sensitivity of CT was higher than that of echocardiography,95.9% vs.84.9%(?2=15.42,P<0.05).In the diagnosis of intracardiac malformation,the sensitivity of CT was lower than that of echocardiography,96.5% vs 98.8%,but the difference was not statistically significant(?2=1.12,P>0.05).Conclusion: CT is of great importance and value in the diagnosis of complex congenital heart disease in children,especially in the diagnosis of extracardiac malformations,with a higher sensitivity compared to transthoracic echocardiography.However,echocardiography has advantages in detection of intracardiac malformation.CT combined with transthoracic echocardiography is of great value in the diagnosis of complex congenital heart disease in children,which can improve the accuracy of diagnosis.Part 2 Clinical value of three-dimensional printing in children with complex congenital heart diseaseObjective: Preoperative planning for children with complex congenital heart diseases remains crucial and challenging.This study aimed to investigate the clinical value of three-dimensional printed patient-specific heart models in the presurgical planning for children with complex congenital heart disease.Methods: From May 2017 to January 2018,15 children diagnosed with complex congenital heart disease were included in this study.The Digital Imaging and Communications in Medicine(DICOM)files of computed tomography angiography images were collected and imported into Mimics 19.0 and 3-Matic 11.0 software for reconstruction based on 3D threshold segmentation method.Upon reconstruction,the data were exported as 3D virtual models in STL form and imported into 3D printer.At last,15 patient-specific heart models were successfully printed based on CT imaging reconstruction by a 3D printer with photosensitive resin material using the stereolithography technology.For children with complex congenital heart disease,their surgery options were evaluated by a sophisticated cardiac surgeon group with medical history,imaging and 3D printed heart models.Surgeries were performed in those who had surgery indications.Results: Fifteen patient-specific 3D printed heart models were successfully printed before decision-makings.Based on medical history,imaging and 3D heart models,12 children had surgery indications and underwent operations,one child diagnosed with ascending aorta and aortic arch dysplasia,hypoplastic left heart syndrome,patent ductus arteriosus,ventricular septal defect,atrial septal defect and pulmonary artery hypertension had surgery indications,but the parents gave up treatment.While the other two did not have surgery indications because mild malformations and no obvious symptoms were manifested.All surgical procedures for children undergoing surgeries are consistent with preoperative planning.The anatomical information detected during surgeries were completely consistent with 3D heart models.Unfortunately,one child diagnosed with complete transposition of great arteries combined with interruption of aortic arch(type A)died 5 days after operation due to postoperative low cardiac output syndrome.The other 11 children who underwent operations were discharged from hospital uneventfully.Two cases of supracardiac TAPVC were followed-up 6 months after surgery and their 3D cardiac model were printed,and the left superior pulmonary vein of one case was slightly stenotic,the other one had no obvious stenosis.The cardiac surgeons,especially the younger ones,considered that these 3D printed heart models with tangible,physical and comprehensive illustrations,were beneficial for preoperative planning of complex congenital heart diseases.Conclusion: 3D printed heart models are beneficial and promising in personalized preoperative planning for complex congenital heart disease and are able to help confirm or even improve the surgery options.Part 3 Accuracy of CT based on semiautomatic 3D thresholdbased segmentation in quantification of ventricular volume of porcine heart in vitroObjective: To investigate the accuracy of CT based on semiautomatic 3D threshold-based segmentation in quantification of ventricular volume of porcine heart in vitro.Methods: Eight fresh isolated porcine hearts were obtained,the atrial structure was removed,remained the left and right ventricle structure,medical gauze was inserted into the left and right ventricles to form the ventricular cavity,and the porcine hearts were placed in 10% formalin solution for 10 days for fixation.After fixation,the curable silica gel was perfused into the left and right ventricles and subjected to CT scanning.After scanning,based on 3D threshold-based segmentation,the post-processing software was used to calculate the volume of the left and right ventricles of the isolated porcine heart,and the solidified ventricular silicone mold was taken out.The actual mold volume measured by drainage method was recognized as the gold standard of the ventricular volume,each volumetric value was calculated and measured three times to average.The CT measuring results of ventricular volume were compared with the gold standard.Results: There was no significant difference between the left and right ventricular volume of the isolated porcine heart measured by CT based on 3D threshold-based segmentation method and the average volume of the silicone mold.The left ventricular volume of CT measurement and gold standard was 12.9 ± 1.2 ml vs.13.2 ± 1.3 ml(t =-1.059,P=0.325).The right ventricle was 27.7 ± 3.6 ml vs.28.2 ± 3.2 ml(t=-1.121,P=0.299),and the calculated volume was highly correlated with the water displacement(left ventricle r=0.845,P=0.008;right ventricle r=0.933,P =0.001),Bland-Altman consistency analysis showed a high consistency between the two methods.Conclusion: CT is able to evaluate the left and right ventricular volume of isolated porcine hearts based on semiautomatic 3D threshold-based segmentation method with high accuracy.Part 4 CT quantification of ventricular volumetric parameters based on semiautomatic 3D threshold-based segmentation in children with tetralogy of FallotObjective: To investigate the clinical value of CT based on semiautomatic 3D thresholdbased segmentation method in evaluating cardiac volume in children with tetralogy of Fallot.Methods: Twenty-three children with tetralogy of Fallot who underwent surgery in our hospital from November 2017 to July 2018 were included in this study.CT scanning were performed before and 6 months after surgery.CT images were acquired and segmented by semiautomatic 3D threshold-based segmentation method to evaluate left and right ventricular volume and cardiac function parameters including left and right ventricular end-diastolic volume,end-systolic volume,stroke volume,and ejection fraction.The left and right ventricular volume and cardiac function parameter changes of children with tetralogy of Fallot preoperatively and 6 months after operation were statistically compared.Results: CT based on semiautomatic 3D threshold-based segmentation can both simultaneously evaluate left and right cardiac function parameters in children with tetralogy of Fallot.There was no significant changes in left ventricular function parameters between the six month after surgery and the preoperative period,the difference was not statistically significant.Right ventricular end-systolic volume six months after surgery was higher than the preoperative period,23.93 ± 7.44 ml/m~2 vs.19.80 ± 6.52 ml/m~2,but the difference was not statistically significant(P=0.061).Right ventricular end-diastolic volume six months after surgery was higher than preoperative volume,49.67 ± 14.82 ml/m~2 vs.46.59 ± 14.46 ml/m~2,but the difference was not statistically significant(P=0.086);and the right ventricular ejection fraction was significantly lower than that before surgery 51.83 ± 4.26% vs.57.50 ± 5.04%,the difference was statistically significant(P=0.001).Conclusion: CT based on semiautomatic 3D threshold-based segmentation method can accurately evaluate the preoperative and postoperative left and right cardiac function in children with tetralogy of Fallot,and can detect the early decline of right cardiac function after surgery,which is important for the assessment of prognosis in children with repaired tetralogy of Fallot.