| Part 1 The value of wide-detector Revolution CT in diagnosis of congenital heart disease in infants: A angiography study using prospective ECG-gated technique and 70 k V tube voltageObjective: To investigate the value of wide-detector Revolution CT in the diagnosis of infants and children with congenital heart disease(CHD),by the angiography using prospective ECG-gated technique and 70 k V tube voltage.Material and Method: Forty-five infants and children with complicated congenital heart disease underwent echocardiography and CT angiography,with prospective ECG-gated technique and 70 k V tube voltage.According to the surgical findings,we calculated and compared diagnostic efficiency of CT angiography and echocardiography.The image quality of cardiac structure and extra-cardiac vascular structures of 256-MDCT and the estimation of beam-hardening artefact were independently evaluated by two cardiac radiologists with more than 5 years’ experience using a five—point scale.The objective quality evaluation of image was measured by the third senior cardiac radiologist.The radiation effective dose(ED)and iodine dose were calculated.Results: There are 25 separate cardiovascular anomalies,including 7 abnormal cardiac structure and 18 extra-cardiac vascular anomalies among all patients.For congenital abnormal cardiac structure,the diagnostic accuracy of Revolution CT angiography and ultrasound was 98.41 % and 99.05 % and the detectable rate of two method was 94.59 % and 95.95 %,respectively.For cardiac vascular anomalies,there was no significant difference in the diagnostic accuracy and detectable rate between two methods(χ2=0.506 and 0.150,P>0.05).However,for extra-cardiac vascular anomalies,there was significant difference regarding to the diagnostic accuracy(99.75 % vs 98.77 %,χ2=5.373,P<0.05)and the detectable rate(98.65 % vs 87.84 %,χ2= 6.864,P<0.05)between these two methods.The sensitivity,specificity,positive predictive value,negative predictive value and coincidence rate were 96.62 %,99.80 %,98.62 %,99.50 % and 99.38 %,respectively by Revolution CT angiography,and 91.89 % 、99.90 %、99.27 % 、98.79 % and 98.84 %,respectively by ultrasound.The mean score of subjective image quality was 4(4-5).The mean beam-hardening artefact scored was 4(3.5-4).The mean attenuation in the ascending aorta,the descending aorta and the pulmonary trunk were(355.65±104.34)HU,(344.35±93.31)HU,[357.80(295.25-460.05)] HU,respectively,the noise of CT value in the ascending aorta,the descending aorta and the pulmonary trunk were [32.80(29.40-38.30)] HU,(29.13±7.57)HU,(31.10±8.00)HU,respectively,and the SNR in the ascending aorta,the descending aorta and the pulmonary trunk were(10.24±2.92),[11.54(9.28-14.60)],[12.04(10.22-14.74)],respectively.ED remains low with an average of [0.20(0.16-0.22)] m Sv and the mean iodine dose was [1.79(1.28-2.69)] g.Conclusions: The wide-detector Revolution CT angiography,with 70 k V tube voltage and the prospective ECG-gated technique,can provide high accuracy for the assessment of CHD in infants and children.Meanwhile,this method can keep good image quality,with the low radiation dose.Part 2 The value of low dose wide-detector revolution CT angiography in the evaluation of left ventricular function for infants and children with congenital heart diseaseObjective: To investigate the value of Revolution CT angiography with low radiation dosage in the evaluation of left ventricular function for infants and children with congenital heart disease(CHD).Material and Method: Forty-three infants and children with CHD(18 males and 25 females;mean age = 6.70 months,range: 2.97-23.00 months;mean body weight = 6.00 kilogram,range: 5.00-10.00 kilogram)were enrolled.There 34 patients whose age were lower than 3 years’ old among all patients.All patients underwent CT angiography on the Revolution CT,a scanner with wide-detector(the wideness = 16 cm)that enables heart scanning with low radiation dosage and two-dimensional echocardiography(2D-ECHO).The CT data were collected in one heart cycle and reconstructed with 10% R-R interval.After that,the time-volume curve was obtained and used to define the left ventricular end-systolic and left ventricular end-diastolic phases.Then,the left ventricular functional parameters,including the Left Ventricle End-systolic Volume(LVESV),Left Ventricle End-diastolic Volume(LVEDV),Left Ventricle Stroke Volume(LVSV)and Left Ventricle Ejection Fraction(LVEF),were calculated.The Wilcoxon signed ranks test and Pearson’s correlation analysis were performed to examine the correlation between the results from CT angiography and 2D-ECHO examination.According to the surgical results,we calculated the diagnostic efficiency of Revolution CT angiography.According to clinical manifestations and the degree of disease,two cardiac surgeons divided patients whose age lower than 3 years’ old into high-risk group and low-risk group.The Mann-Whitney U nonparametric test and binary logistic regression analysis were performed to examine the high-risk group and low-risk group.The radiation effective dose(ED)and iodine dose were recorded.Results: There 29 patients underwent surgical treatment,the sensitivity,specificity,positive predictive value,negative predictive value and coincidence rate were 95.54%、99.81%、99.07%、99.06% and 99.06%,respectively by Revolution CT angiography according to the surgical results.The CT angiography results in the little overestimation of LVESV,LVEDV and LVSV,and little underestimation of LVEF,with 2D-ECHO measurement as standard.Despite that,the strong correlation was found between the results from CT angiography and 2D-ECHO examination: LVES(r = 0.935,P=0.00),LVED(r= 0.922,P=0.00),LVSV(r = 0.907,P=0.00)and LVEF(r = 0.862,P=0.00).There are 34 patients whose age lower than 3 years’ old,the high-risk group including 21 patients and low-risk group including 13 patients.there was significant difference regarding to the LVESV、LVEDV and LVSV between these two groups(P<0.05).However,there was no significant difference in the LVEF between two groups(P>0.05).The recorded ED was 0.30±0.07 m Sv and the mean iodine dosage was [1.54(1.28-2.56)]g,all of which indicate low radiation level during CT angiography.Conclusions: Revolution CT angiography with low radiation dosage is an accurate and feasible method to assess the left ventricular function;it provides an alternative for assessment of CHD. |
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