Study Of Imaging Modalities In Diagnosing Tracheobronchial Anomalies Of Congenital Heart Disease

ObjectiveTo study the low dose CT scan mode and scan parameters and to optimize the low dose scan protocols in animal-miniature Bama pigs experiment. To further evaluate the value of low dose cardiac CT in diagnose of pediatric congenital heart disease(CHD) with tracheobronchial anomaliesTo study the different MR sequences for displaying the tracheobronchial tree in animal-miniature Bama pigs experiment. To further evaluate the value of MR sequences in diagnose of pediatric congenital heart disease with tracheobronchial anomalies and to investigate the feasibility of using MR sequences to diagnose the tracheobronchial anomalies. Materials and Methods 1, Four Bama pigs(weight range from 7.5-14.4kg) underwent cardiac CT scan under anesthesia. Prospective ECG-triggering and retrospective ECG-gating cardiac CT were performed with regular 80 KVp, tube current range from 60-180 m A and ECG-controlled tube current modulation(tube current range from 80-220 m A. ASIR(80%) reconstruction was used.Two Bama pigs(weight range from7.5-10.5kg) underwent cardiac MRI under anesthesia. Three sequences which inchuded CE-MRA, 3D-TFE and 3D-B-TFE were performed. 2, Three hundred twenty three patients underwent low dose Prospective ECG-triggering cardiac CT. Three groups were divided by body weight, which were 0-5kg, 6-11 kg and 11-15 kg. Regular tube voltage and different tube current were used. 3, Three hundred fifty seven patients underwent cardiac MRI. 3D-TFE was used in all cases. In 46/357 cases, the results of 3D-TFE compared with those of CT. Twenty-six cases underwent 3D-TFE and 3D-B-TFE sequences simultaneously and the results of MRI compared with those of CT. Results 1, Comparison of radiation dose estimation was performed between prospective ECGtriggering and retrospective ECG-gating cardiac CT under same scan parameter and subjective imaging score. The reduction rate of effective radiation dose in two pigs was 81% and 77% respectively. The effective radiation dose was subm Sv. The subjective imaging scores in great vessels under low dose protocols(80KVp, 100 m A) were good(3.9-4.5). The scores were excellent in tracheobronchial tree(over 4) under different scan parameters.The subjective imaging score of 3D-TFE was highest(5.0) among three sequences. 2, The Interobsever agreement was reached in subjective scores of evaluation of great vessels and tracheobronchial tree among three groups under same scan parameters(Kappa 0.72-0.89; 0.59-0.91). There was significant difference under different scan parameters in 0-5kg and 6-10 kg groups, no significant difference existed in 11-15 kg group. There was no significant difference among three groups in CNR.The reduction rate of radiation dose under different scan parameters among three groups were 64.3%, 38.8% and 32.9%. Comparing with the virtual conventional retrospective ECG-gated mode, there was a significant difference in effective radiation dose. The reduction rate was 75%, 79% and 85% respectively.In 323 cases, the ratio of acyanotic and cyanotic CHD was 2.3:1. The preoperative cases were account for 88.2%. Acyanotic CHD included left-right shunt diseases mainly and cyanotic CHD included conotruncal anomalies mainly. There were 83 cases of tracheobronchial anomalies in 323 cases, in which 65 cases of tracheobronchial stenosis, 13 cases of trachea bronchus, 4 cases of bronchial isomerism and 1 case of situs inversus’ type of bronchus. The causes of tracheobronchial stenosis were mainly vascular anomalies such as double aortic arch and right aortic arch with aberrant subclavian artery.The findings of 214 preoperative cardiac CT were compared with surgical results for assessing diagnostic accuracy. The diagnostic accuracies of extracardiac vessels and intracardiac structures were 100% and 94% respectively. 3, In 357 cases, most cases were preoperative which were account for 92%, postoperative cases were account for 8%. Acysnotic CHD cases were account for 71% and cyanotic CHD 29%. There were 97 cases of tracheobronchial anomalies in 357 cases, in which 66 cases of tracheobronchial stenosis, 18 cases of trachea bronchus, 13 cases of bronchial isomerism and 3 case of situs inversus’ type of bronchus. There was excellent intermodality agreement between 3D-TFE and MSCT for the detection of tracheobronchial anomalies(Kappa 0.868). The sensitivity, specificity, PPV, NPV, PLR and NLR of 3DTFE and 3D B-TFE were 90%, 84%, 83%, 91%, 5.6, 0.1 and 80%、62%、71%、2.1、0.3, respectively. ConclusionsProspective ECG-triggering cardiac CT scan mode is the first choice in low dose cardiac CT scan mode and the effective dose estimation can reach subm Sv. Low dose cardiac CT will be widely used in diagnosing congenital heart disease.3D-TFE can be the first choice of MRI sequences for congenital heart disease with tracheobronchial anomalies at present. MRI can be used in diagnosis of tracheobronchial anomalies.