Common atrium and the associated malformations: Evaluation by low-dose dual-source computed tomography

Abstract

Common atrium (CA) is a rare complex congenital heart disease. The studies of CA are mostly case reports, while few have been done regarding its morphological characteristics. We aimed to determine CA characteristics and diagnostic accuracy in assessing associated malformations in these patients with low-dose dual-source computed tomography (DSCT).Twenty-one pediatric and adolescent CA patients underwent low-dose DSCT. Different ventricular types and associated malformations were assessed. The diagnostic accuracy of DSCT and transthoracic echocardiography (TTE) in evaluating associated malformations were assessed. The effective doses of DSCT were calculated.Patients (n = 21) were divided into CA with biventricular physiology (n = 7) and CA with single ventricle (SV) (n = 14). There were 3 types of SV morphology: single left ventricle (n = 5), single right ventricle (n = 6), and undifferentiated ventricle (n = 3). In all, 22 associated malformations were seen in CA and 56 in CA with SV. DSCT was superior to TTE for detecting intracardiac anomalies (sensitivity: DSCT, 92.31% vs TTE, 76.92%), great vessels anomalies (sensitivity: DSCT, 100.00% vs TTE, 77.50%), and of collateral vessels (sensitivity: DSCT, 100% vs TTE, 20.00%). The estimated mean effective dose was 0.95 ± 0.44 mSv (<1 mSv).This study indicated that low-dose DSCT is an ideal alternative for pediatric and adolescent patients with CA, providing morphological details of CA and associated malformations with high accuracy.

Figure 1

Different types of CA based on the morphological characteristics of ventricle. (A) CA with biventricular physiology. The CA is both connected to LV and RV. (B) CA with single LV. The trabeculae (arrow) of main ventricular chamber are thin and there is a rudimentary chamber (∗) located in the right side of the main chamber. (C) CA with single RV. The trabeculae (arrow) of main ventricular chamber are coarse. (D) CA with indeterminate ventricle. Single ventricle chamber is of indeterminate morphology. CA = common atrium; LV = left ventricle, RV = right ventricle, SV = single ventricle.

Figure 2

CA with single right ventricle in a female aged 9 years. (A) Axial image reveals a CA connected to one ventricular chamber with coarse trabeculae. (B) MPR image shows that a funnel-shaped patent ductus arteriosus arise from the aorta arch into the left pulmonary artery (arrow). (C) VR image showed a collateral vessel laying on the back of the descending aorta (arrow). CA = common atrium, MPR = multiple planar reconstruction, SV = single ventricle.

Figure 3

CA with indeterminate ventricle in a female aged 11 years. (A) Axial CT image reveals a CA with SV accompanied by dextrocardia. The morphological characteristics of SV cannot be identified. (B) Axial CT image shows a right-sided AoA and a persistent left superior vena cava (∗). (C) VR image shows a drainage of left pulmonary veins and partial right pulmonary veins into the right superior vena cava. AoA = aortic arch, CA = common atrium, SV = single ventricle, VR = volume reconstruction.