Low-dose prospective ECG-triggering dual-source CT angiography in infants and children with complex congenital heart disease: first experience Ximing Wang, M.D., Zhaoping Cheng, M.D., Dawei Wu, M.D., Lebin Wu, M.D., Yanhua Duan, M.D. Shandong Medical Imaging Research Institute P.R. China
Study Background Conventional angiocardiography (CA) 1. the gold standard method 2. Invasive mortality of around 1% 3. high effective dose 4.6 msv Transthoracic echocardiography (TTE) 1. the first-line method noninvasive, safe 2. operator-dependent 3. relatively small acoustic window Magnetic resonance imaging (MRI) 1. require sedation time-consuming Computed Tomography angiography (CTA) 1. a new noninvasive method fast 2. key point How to reduce the dose?
Dose Reduction Strategy Use low voltage technique whenever possible. Minimize Tube current according to body size. Use highest pitch for a given heart rate. Use ECG x-ray modulation. Prospective ECG-triggering
Purpose To explore the clinical value of low-dose prospective ECG-triggering dual-source CT (DSCT) angiography in infants and children with complex congenital heart disease (CHD).
Materials and Methods Fifteen children (mean age: 10 months, range: 2months-3years; male 9; mean weight: 8.5Kg; mean heart rate: 106) All patients underwent both DSCT angiography and Transthoracic echocardiography (TTE) Diagnosis proven by operations (palliative or corrective n=13) or Conventional angiocardiography (n=2)
Individual DSCT scan parameters Weight (kg) Tube Voltage (kv) Tube Current (mas) <5 80 40~60 5~10 80 60~80 10~20 100 80~100
Result 1 Final diagnosis of fifteen patients tetralogy of Fallot n=5 double outlet right ventricle n=2 transposition of great arteries n=2 total anomalous pulmonary venous return n=1 pulmonary artery atresia with ventricle septal defect n=2 interrupted aortic arch n=1 coarctation of aorta n=1 anomalous origin of one pulmonary artery n=1
Result 2 A total of 56 cardiac deformities Incardiac deformities(25): the accuracy of DSCT and TTE were 88% and 100% respectively. Extrocardiac deformities(31) :the accuracy of DSCT and TTE were 97% and 68% respectively.
Result 3 Radiation Dose in prospective ECGtriggering dual-source CT (DSCT) angiography Volume CT Dose Index (mgy) DSCT 1.33±0.29 (0.83 1.65) Effective Dose (msv) 0.46±0.12 (0.27 0.65)
Pulmonary atresia with coronary artery fistula 80 Kv/80 mas (Effective Dose 0.42mSv) (a) MIP and (b) VR reformatted images show the fistula (thick arrow) between the proximal RCA and MPA. (c) MIP reformatted image shows the VSD and overriding aorta. (d) VR reformatted images shows two MAPCAs (slim arrows) arising from the descending aorta.
Coarctation of aorta 80 Kv/60 mas (Effective Dose 0.29mSv) Six-month-old girl with coarctation of aorta. (a) MPR image shows simultaneously the ASD and muscular ventricular VSD. (b) VR reformatted image (posterior view) demonstrates narrowing of the aorta (arrow).
Tetralogy of Fallot 80 Kv/60 mas (Effective Dose 0.31mSv) (a) VSD and overriding aorta on the reformatted images. (b) MIP image during systole shows critical stenosis of the right ventricular outflow tract (RVOT)
Tetralogy of Fallot with coronary artery anomaly 80 Kv/80 mas (Effective Dose 0.43mSv) MIP reformatted image shows critical stenosis of the right ventricular outflow tract (RVOT). The branches of anomalous right coronary artery crossed anteriorly the ROVT.
Transposition of great arteries with single coronary artery anomaly 80 Kv/100 mas (Effective Dose 0.58mSv) MPR and VR images show the transposition anatomy. and Single coronary artery. Both right coronary artery and left coronary artery arose from the non-coronary sinus of Valsalva (NSV) with a common trunk. The left main coronary crossed between the MPA and the left atrium.
Interruption of aortic arch,iaa 80 Kv/100 mas (Effective Dose 0.52mSv) Type A: The left subclavian artery origins from the ascending aorta.
Conclusions Low-dose prospective ECG-triggering DSCT angiography was more sensitive to evaluate the anomalies of systemic vessel, pulmonary vessel, and coronary artery compared with TTE. It is extremely valuable for planning the operative procedure especially in the patients with complicated congenital heart disease. Low-dose prospectively ECG-triggering DSCT angiography allows the accurate diagnosis of anomalies in infants and children with complex CHD compared with TTE..