Detection of coronary artery anomaly in patients with complex congenital heart disease by dual-source CT

Abstract

Objective To explore the clinical usefulness of low-dose dual-source CT (DSCT) angiography in detecting coronary artery anomaly (CAA) in patients with complex congenital heart disease (CHD). Methods A total of 615 consecutive patients with complex CHD who underwent DSCT angiography between 2008 and 2012 were retrospectively reviewed. According to the ultrasonic results, a total of 312 patients with tetralogy of Fallot (n=176 cases) or double outlet right ventricle (n=72 cases) or pulmonary artery atresia (n=64 cases) were included. Scans were divided into 3 groups: retrospective electrocardiogram (ECG)-triggered spiral scanning in 75 cases, prospective ECG-triggered spiral scanning in 158 cases, and prospective ECG-triggered high-pitch spiral scanning in 79 cases. The subjective image quality was evaluated with a four-point scale by two radiologists. Radiation dose values were calculated. Interobserver agreement in subjective image quality grading was assessed by using Kappa statistics. The scanning groups were compared with the Kruskal-Wallis test. Results The incidence of CAA was 8.0% (25/312) . CAA was detected in 7.9% (14/176) patients with tetralogy of Fallot, 8.3% (6/72) patients with double outlet right ventricle, 7.8% (5/64) patients with pulmonary artery atresia. In 76% (19/25) of the patients, the anomalous vessels were crossing the right ventricular outflow tract (RVOT). Thirty of 312 CT examinations were nondiagnostic (9.6%). Two radiologists acquired good agreement (Kappa=0.72, P<0.01). The median subjective image quality score of three scan groups was 3 (range 1—4). The score in high-pitch spiral scanning group was significantly lower than those in other two groups (H=29.1, P<0.01) . Retrospective ECG-triggered scans had a median dose of 1.19 mSv (range 0.52—3.29 mSv) , prospectively ECG-triggered scans had a median dose of 0.51 mSv (range 0.27—2.13 mSv) , and prospectively ECG-triggered high-pitch spiral scans had a median effective dose of 0.30 mSv (range 0.18—0.62 mSv) . The difference between groups was statistically significant (H=160.0, P<0.01) . Conclusions DSCT angiography is a reliable diagnostic method for the assessment of CAA with complex CHD and low-dose prospectively ECG-triggered DSCT scan is the best choice. Key words: Coronary artery disease; Heart defects, congenital; Tomography, X-ray computed