The Application Of Flash Spiral Acquisition By Dual-Source CT In Children With Cardiovascular Airway Constriction

Part 1 Multi-mode Comparative Study of Flash Spiral Acquisition and Prospective ECG-gated Sequential by Dual-source CT in Children with Congenital Heart DiseaseObjectiveThe goal of this study was to compare the difference between two CT angiography modes in children with congenital heart disease,the flash spiral acquisition by dual-source CT(DSCT)and the prospective ECG-gated sequential by DSCT.And to explore the application value of dual-source CT flash spiral acquisition in children with CT angiography.MethodsAfter the approval of institutional review board and informed consent was obtained from children's parents,65 children suspected with congenital heart disease were prospectively underwent CT angiography examination,and 60 children were finally enrolled in this study.There were 30 children(male 13,female 17)underwent CT angiography examination with flash spiral acquisition in this study,and the other 30 children(male 10,female 20)underwent prospective ECG-gated sequential.We use CCA or conventional surgical results as the reference golden standard,the diagnostic accuracy of the two groups were evaluated.Images were analyzed by two experienced radiologists using a 5-grade scoring system subjectively as follows:(5=the image is clear,no exactly motion artifact and obvious noise;4=minimal noise and motion artifact,no diagnostic difficulties;3=the image is blurred with moderate noise and motion artifact,but the abnormal structure can be diagnosed;2=serious noise and motion artifact,and the diagnosis is difficult;1=the image is not recognizable.Image scores larger than or equal to 3-grade are considered to be the qualified images).The Volume CT dose index(CTDIvol)and Dose-length product(DLP)were recorded to calculate effective dose(ED).ResultsThere were no statistical difference on the age(t=0.19,P>0.05),body weight(t=0.35,P>0.05)and heart rate(t=0.22,P>0.05)between the two groups.Compared with the reference golden standard,110 cardiovascular anomalies were diagnosed in flash spiral acquisition group,the sensitivity,specificity,PPV,NPV and diagnostic accuracy were 94.55%,99.78%,99.05%,98.71%and 98.77%,respectively.And 117 cardiovascular anomalies were diagnosed in prospective ECG-gated sequential mode group,the diagnostic accuracy of the above parameters were 96.58%,99.56%,98.26%,99.12%and 98.95%,respectively.There was excellent agreement for the total image quality score of the two observers(t=1.90,P>0.05)as follows:(4.53 ± 0.73)and(4.83 ±0.46)respectively.There was significant difference regarding to the CTDIvol(t=11.15,P<0.01),DLP(t=7.85,P<0.01)and ED(t=12.82,P<0.01)between flash spiral acquisition group(0.24 ±0.05mGy,4.27±1.48mGy · cm and 0.27 ±0.06mSv)and prospective ECG-gated sequential mode group(0.96±0.35mGy,10.50±4.09mGy · cm,0.67±0.16mSv).The flash spiral acquisition group decreased the dose by 60%compared with the prospective ECG-gated sequential mode group.ConclusionBoth flash spiral acquisition and prospective ECG-gated sequential mode by dual-source CT can provide high accuracy.Compared with the ECG-gated sequential mode,the radiation dose was significantly decreased in the flash spiral acquisition group,which can be used in children with CT angiography.Part 2 To Explore the Application Value of Flash Spiral Acquisition by Dual-source CT in the Diagnosis of Congenital Heart Disease Accompanied with Airway ConstrictionObjectiveThe object of our study is to explore the application value of flash spiral acquisition by Dual-source CT in the diagnosis of congenital heart disease accompanied with airway constriction.MethodsA total number of 107 children suspected with cardiovascular airway compression underwent flash spiral acquisition by dual-source CT from January 2013 to December 2015,and 99 children were finally included in this study.There were 40 males and 59 females.The mean age was 22 months(1?16months)and the mean body weight was 10±7.7 kg(2.8?45kg).Images were analyzed by two experienced radiologists using a 5-grade scoring system subjectively as follows:(5=the image is clear,no exactly motion artifact and obvious noise;4=minimal noise and motion artifact,no diagnostic difficulties;3=the image is blurred with moderate noise and motion artifact,but the abnormal structure can be diagnosed;2=serious noise and motion artifact,and the diagnosis is difficult;1=the image is not recognizable.Image scores larger than or equal to 3-grade are considered to be the qualified images).The airways were divided into four segments as follows:part ?,lower third of the trachea;part ?,right main bronchus;part ?,left main bronchus;part IV,lobe bronchus.We use the diagnostic criteria to determine airway constriction.Multiple planar reformation(MPR)and volume rendering(VR)were used to show the anatomic structures around the narrow segment,and to define the responsible anomalies and location of the airway constriction.The characteristics of pulmonary lesions were observed in lung window and minimum intensity projection(MinIP).ResultsThe DLP was(7.32±6.19)mGy*cm and ED was(0.39 ±0.20)mSv in the 99 children.All images meet the diagnostic requirements.Two radiologists made good agreement(K=0.754,P<0.05).Of all the 99 children,a total of 104 constriction was diagnosed of having tracheobronchial constriction by vascular abnormalities.Presenting vascular malformations that lead to airways constriction included pulmonary arterial hypertension 38 cases(36.5%),coarctation of aorta 32 cases(30.8%),right-sided aortic arch 14 cases(13.5%),innominate artery tracheal compression 12 cases(11.5%),pulmonary artery sling(5.8%),double aortic arch 1 case(1.0%)and left atrial enlargement 1 case(1.0%).At the same time,we can also see secondary pulmonary lesions,including ground glass opacity 36 cases,consolidation 19 cases,emphysema 66 cases.and post-obstructive pulmonary atelectasis 7 cases.The difference between the type of primary heart disease and the location of the airway constriction was statistically significant(P<0.0001).Airway constrictions caused by congenital heart disease were most likely to occur on the left main bronchus.ConclusionFlash spiral acquisition by dual-source CT can diagnose CHD with airways compression and secondary pulmonary lesions simultaneously,and providing a basis for clinical.