Methodology And Clinical Application Of 64-detector Computed Tomography In Diagnosing Congenital Heart Disease In Children

PartⅠ:64-detector Row CT Cardiovascular Angiography on Technique and Image QualityObjective:To establish the approach of multidetector row CT(MDCT) in diagnosing complex congenital heart disease in children.Materials and methods:We prospectively enrolled forty children with complex congenital heart disease referred for diagnostic cardiac catheterization after initial assessment by echocardiography.MDCT was performed using a 64-detector-row CT scanner with power syringe injection,group by the design of examination(assessing aorta or pulmonary artery).All the source images were interpreted and postprocessed by a cardiac radiologist.CT workstation(General Electric,GE) was used for multiplanar reformation(MPR),curved reformation(CPR), volume rendering(VR) and maximum intensity projection(MIP) images.A multidisciplinary congenital heart disease team evaluated the MDCT images and decided if further diagnostic cardiac catheterization was necessary.The accuracy of MDCT in detecting separate cardiovascular anomalies and quality of imaging were evaluated. Results:A total of 40 children underwent the MDCT scan without contrast media side effect in the study.No further diagnostic cardiac catheterization was needed in any patient.There was no significant difference of signal-to-noise ratio(SNR) and contrastto -noise ratio(CNR) between the two groups(p＞0.05).No obvious beam-hardening artefact was observed.Comparing MDCT with ECHO,there was significant difference of detecting rate in cardiovascular anomalies(detecting rates were 96.77%,90.32% respectively,x~2=4.28,p＜0.05),significant difference of detecting rate in extra-cardiac anomalies(detecting rates were 97.67%,86.05%respectively,x~2=7.98,p＜0.05),and no difference of detecting rate in intra-cardiac anomalies(detecting rates were 94.74%, 100%respectively,p=0.247,p＞0.05).Conclusions:MDCT with Smartprep autotrack software is the important noinvasive imaging modality to diagnose complex congenital heart disease in children.PartⅡ:The Application of 64-detector Row CT in the Diagnosis of Congenital Heart Disease in Children SectionⅠ:The Application of 64-detector Row CT in the Diagnosis of Coarctation of the Arota in Young ChildrenObjective:To assess the reliability of MDCT and reconstruction technique in diagnosing coarctation of the aorta.Materials and methods:Twenty-six patients with suspected coarctation of the aorta underwent both echocardiography and MDCT.In addition to the CT axial slices,reconstructions such as multiple planar reformation,curved reformation and volume rendering were used to diagnose coarctation and associated cardiac abnormalities by two independent observers.The sensitivities of diagnosis were evaluated compared with MDCT and echocardiography.The diameter and distance of coarctation were measured by two independent observers.Results:Twenty-six cases were diagnosed as coarctation of the aorta by MDCT.This included hypoplasia of the aortic arch(n=11).The results were confirmed by surgery.Diagnosis sensitivities of coarctation were 88.46%(23/26) for axial,and 100%for both multiplanar and 3D volume-rendered images.MDCT imaging was able to clearly display the location and extent of the coarctation.The sensitivity of MDCT with three-dimensional reconstructions diagnosis for coarctation of the aorta was 100%,which was higher than that of echocardiography(88.46%,23/26).However,there was no significant difference (x~2=1.41,p＞0.05).Ventricular septum defect(n=15),patent ductus arteriosus(n=12), arotic arch hypoplasia(n=11),and double outlet right ventricle(n=2) were diagnosed by MDCT.Comparing MDCT with ECHO,there was significant difference of detecting rate in cardiovascular anomalies(detecting rates were 97.06%,86.76%respectively,x~2=4.85, p＜0.05).There was an excellent agreement in quantifying the diameters and distances of coarctation by two independent observers(diameters bias 0.11±0.42 mm,and distances bias 0.04±0.47 mm).Conclusions:MDCT with imaging post proceeding represents a reliable noninvasive technique for the assessment of coarctation.It may serve as a noninvasive diagnostic tool before intervention or surgical treatment.SectionⅡ:Evaluation of Pulmonary Blood Supply and Pulmonary Arteries in Children with Complex Congenital Heart Disease by 64-detector Row Computed TomographyObjective:To assess the feasibility of MDCT for the analysis of complex pulmonary blood supply and evaluation of pulmonary artery morphology in children with cyanotic congenital heart disease such as tetralogy of Fallot(TOF) and pulmonary atresia(PA). Material and Methods:Fifty-four patients with TOF,and/or PA underwent MDCT and cardiac catheterization.MDCT and cardiac catheterization were analyzed by two independent observers.Using MPR,and VR,the pulmonary arteries,patent ductus arteriousus(PDA),and aortopulmonary collateral arteries(APCAs) were displayed.The complex pulmonary blood supply was analyzed.Left pulmonary arteries(LPA),right pulmonary arteries(RPA),and the site of maximum stenosis(reduction exceeding 30% diameter was defined as stenosis) were measured independently on MDCT and cardiac catheterization in 54 children.Results:MDCT accurately imaged the pulmonary arteries, PDA,and the origin,course of APCAs,compared to conventional X-ray angiography. There were 31 cases pulmonary blood flow only from ventricle,17 only from PDA and/or APCAs,and 6 from both pulmonary arterial blood flow and systemic arterial blood flow.There was an excellent correlation between MDCT and conventional pulmonary angiography in quantifying the diameter of the left pulmonary arteries(r=0.90, p=0.000) and right pulmonary arteries(r=0.91,p=0.000,respectively).MDCT correctly detected 20 pulmonary arteries stenotic lesions,but 19 pulmonary arteries were detected on invasive angiography,one was misdiagnosed by conventional X-ray angiography. There was an excellent correlation between MDCT and conventional angiograms with respect to evaluation of stenotic sites(n=19,r=0.86,p=0.000).Conclusions:This study demonstrates the feasibility of MDCT in assessing pulmonary artery morphology in children with complex congenital heart disease.SectionⅢ:The Diagnoses of Trachea and Bronchus stenoses by using 64-detector Row Computed Tomography in Children with Congenital Heart DiseaseObjective:To investigate the value of 64-detector row spiral computed tomography in diagnosing tracheobronchial stenosis in children with congenital heart disease.Materials and methods:Sixteen children with congenital heart disease and suspected tracheobronchial stenosis were examined by contrast enhanced MDCT.Conventional axial slices,MPR and VR,virtual tracheobronchoscopy(VTB) were used.Interobserver agreement for the diameters and areas of the narrow tracheobronchus were evaluated with Bland-Altman analysis.Results:CT demonstrated tracheobronchus stenosis in all 16 children due to vascular compression because of left pulmonary artery sling(n=5), pulmonary artery dialatation(n=6),pulmonary artery malposition(n=2),right aortic arch (n=2),and double aortic arch(n=1).All straitness were correctly depicted by conventional axial slices,MPR,VR,and VTB.There was an excellent agreement in quantifying the diameters and areas of tracheobronchus by two independent observers (minor axis bias 0.04±0.35mm,major axis bias 0.24±0.48mm,and area bias 0.11±l.17mm~2).Conclusion:MDCT with reconstruction techniques is effective for the evaluation of tracheobronchial stenosis in children with congenital heart disease.SectionⅣ:the Application of 64-detector Row CT in the Diagnosis of Congenital Coronary Artery Anomalies in ChildrenObjective:To Evaluate the reliability of MDCT with ECG-gated techniques in detection of coronary arteries in children.Materials and methods:Sixteen children were divided into two groups,one needed to detect coronary artery and another needed to detect great artery.The CT scan was acquired using an ECG-gated technique,and the most quiescent phase of the RR interval was selected to represent the ECG-gated images in coronary artery group.Another group acquired images non-ECG-gated.The detection rate and image quality of ten coronary artery segments in the two sets of images were then compared.A two-tailed paired t test was used with P values＜0.05 considered as statistically significant.Results:In all coronary segments the ECG-gated technique had a better detection rate and produced images of better quality.100%of left main coronary artery was detected by MDCT with ECG-gated technique,and 87.5%was detected by MDCT with ECG-gated technique.No significant difference was observed(p=0.5). However,100%distal right coronary artery was detected by MDCT with ECG-gated technique,while 0 was detected by MDCT with ECG-gated technique.The difference was significant(p=0.000).Conclusions:MDCT with ECG-gated techniques is able to detect coronary arteries in most pediatric patients,it is suitable to serve as a noninvasive diagnostic tool to coronary artery anatomy in children.