Application of prospective ECG-gated high-pitch 128-slice dual-source CT angiography in the diagnosis of congenital extracardiac vascular anomalies in infants and children

Abstract

Purpose: To investigate the value of prospective ECG-gated high-pitch 128-slice dual-source CT (DSCT) angiography in the diagnosis of congenital extracardiac vascular anomalies in infants and children in comparison with transthoracic echocardiography (TTE).

Methods: Eighty consecutive infants or children clinically diagnosed of congenital heart disease and suspected with extracardiac vascular anomaly were enrolled, and 75 patients were finally included in this prospective study. All patients underwent prospective ECG-gated high-pitch DSCT angiography after TTE with an interval of 1-7 days. The diagnostic accuracy and sensitivity of high-pitch DSCT angiography and TTE were compared according to the surgical/CCA findings. The image quality of DSCT was assessed using a five-point scale. The effective radiation dose (ED) was calculated.

Results: A total of 17 congenital heart diseases and 162 separate extracardiac vascular anomalies were confirmed by surgical/CCA findings in 75 patients. The diagnostic accuracy of high-pitch DSCT angiography and TTE was 99.67% and 97.89%, respectively. The sensitivity of high-pitch DSCT angiography and TTE was 97.53% and 79.62%, respectively. There was significant difference regarding to the diagnostic accuracy and the sensitivity between high-pitch DSCT angiography and TTE (χ2 = 23.561 and 28.013, P<0.05). The agreement on the image quality scoring of DSCT between the two observers was excellent (κ = 0.81), and the mean score of image quality was 4.1±0.7. The mean ED of DSCT was 0.29±0.08 mSv.

Conclusions: Prospective ECG-gated high-pitch 128-slice DSCT angiography with low radiation dose and high diagnostic accuracy has higher sensitivity compared to TTE in the detection of congenital extracardiac vascular anomalies in infants and children.

Figure 1. An 18-months boy with absence of the right pulmonary artery and major aortopulmonary collateral artery (MAPCA).

Prospective ECG-triggering high-pitch DSCT angiography was performed at 80 kV and 80 mAs/rotation (effective radiation dose, 0.29 mSv). (a) Axial multiplanar reformatted image shows the main pulmonary artery (MPA) continues to the left pulmonary artery (LPA). (b) Volume-rendered (VR) image (inferior view) and (c) VR image (posterior view) show the absence of the right pulmonary artery (RPA), and the right lung is supplied by a MAPCA arising from the descending aorta (DA). (d) Two dimensional echocardiography from the parasternal approach mistakes the top of left atrium (LA) for RPA, and the LPA is not shown as being obscured by the aerated lung. This case was misdiagnosed as pulmonary sling on TTE. AA =  ascending aorta, SVC =  superior vena cava.

Figure 2. A 20-months boy with double aortic arch and tracheal stenosis.

Prospective ECG-triggering high-pitch DSCT angiography was performed at 80 kV and 80 mAs/rotation (effective radiation dose, 0.21 mSv). (a) Thin-section axial MIP, (d) volume-rendered (VR) image (posterior view) and (e) VR image (superior view) show the vascular ring formed by two aortic arches. (b) Thin-section coronal minIP, (c) airway VR image and (f) airway and vascular VR image show the tracheal stenosis compressed by the vascular ring. LAr  =  left aortic arch, RAr  =  right aortic arch.

Figure 3. A 6-months girl with coarctation of the aorta (CoA), aortic dysplasia and ventricular septal defect (VSD).

Prospective ECG-triggering high-pitch DSCT angiography was performed at 80 kV and 60 mAs/rotation (effective radiation dose, 0.24 mSv). (a) Axial multiplanar reformatted image shows VSD. (b) Thin-section oblique sagittal MIP and (c) volume-rendered image (posterior view) show coarctation of the aorta (white arrow) and aortic dysplasia. (d) Two dimensional echocardiography identified CoA, but it missed the aortic dysplasia. RV  =  right ventricle, LV  =  left ventricle, Ar  =  aortic arch, DA  =  descending aorta.

Figure 4. A 5-year girl with Tetralogy of Fallot and pulmonary sling.

Prospective ECG-triggering high-pitch DSCT angiography was performed at 80 kV and 100 mAs/rotation (effective radiation dose, 0.29 mSv). (a) Oblique coronal multiplanar reformatted (MPR) image, (b) Oblique sagittal MPR image, (c) axial thin-section MIP and (d) volume-rendered image are before operation, these images show ventricular septal defect (VSD), overriding aorta, right ventricular outflow tract stenosis, pulmonary sling and the stenosis of the initial part of the left pulmonary artery (LPA). (e), (f), (g) and (h) are after operation. (i) is the operation picture. RV  =  right ventricle, LV  =  left ventricle, AA  =  ascending aorta, MPA  =  main pulmonary artery, RPA  =  right pulmonary artery, SVC  =  superior vena cava.