Accuracy, image quality and radiation dose comparison of prospective ECG-gated sequential and high-pitch acquisition on 128-slice dual-source CT angiography in infants and children with congenital heart disease / 中华放射学杂志

ABSTRACT

Objective To compare the accuracy, image quality and radiation dose between prospective ECG?gated sequential and high?pitch acquisition on 128?slice dual?source CT (DSCT) angiography in infants and children with congenital heart disease (CHD). Methods Ninety?two children with CHD from October 2011 to February 2013 were prospectively enrolled and assigned into two groups according to random number table. Forty?six patients underwent DSCT angiography with sequential mode, and the other 46 patients were examined with high?pitch mode. With surgical and/or DSA results as the standard, the diagnostic accuracy and sensitivity of the two groups for the intracardiac structures, extracadiac and coronary artery anomalies were evaluated, and the comparison was analyzed by Fisher exact test. A 5?grade scoring system was used to interpret the image quality of intracardiac structures, great vessels and the proximal and middle segments of coronary arteries. Interobserver agreement on grades of image quality was assessed by Kappa statistics. The image quality scores were compared using the Mann?Whitney U test. The Student t test or the Mann?Whitney U test was used to analyze the differences between the two groups regarding to patients' age, weight , heat rate, CT attenuation, image noise and SNR in the ascending aorta and the pulmonary trunk as well as radiation dose. Results All 92 patients successfully underwent DSCT angiography. The diagnostic accuracies of intracardiac anomalies by high?pitch group and sequential group were 95.65%(88/92) and 99.28%(274/276), showed significant difference between the two groups (P0.05) .There was no significant difference in the diagnostic accuracy and sensitivity of extracadiac anomalies between the two groups (P>0.05). The diagnostic accuracies of coronary artery anomalies by high?pitch group and sequential group were 93.48%(43/46) and 100.00%(46/46), showed no significant difference between the two groups (P>0.05), but there was significant difference in the sensitivity of coronary artery anomalies (50.00%(3/6) , 100.00% (11/11)) (P0.05). The median image quality scores of intracardiac structures and proximal and middle segments of coronary arteries respectively by high?pitch group were 4.00 and 3.00, and 5.00 and 4.00 respectively by sequential group. The image quality of intracardiac structures (U=594.500, P<0.05) and proximal and middle segments of coronary arteries (U=397.500, P<0.05) was significantly better in the sequential group than that in the high?pitch group. There was no significant difference between the two groups in CT attenuation, noise and SNR of the ascending aorta and pulmonary trunk. The mean effective doses of the high?pitch group and the sequential group were(0.27±0.11)and(0.39±0.17)mSv, and showed significant difference between the two groups (t=4.316, P<0.05). Conclusions Both sequential and high?pitch mode of 128?slice DSCT angiography provide high accuracy for the assessment of CHD in infants and children, while the high?pitch mode, though with some image quality declined, shows further significantly lower radiation dose.