Is combined MDCT and echocardiography needed to guarantee accuracy in diagnosis and surgical planning of DORV and associated anomalies?

Background The term of Double-outlet right ventricle (DORV) is used to describe a spectrum of complex congenital cardiac malformations where anomalies of the ventriculo-arterial alignment are noted where both great arteries (pulmonary artery and aorta) originate completely or predominantly from the right ventricle. The purpose of this study is to evaluate the diagnostic accuracy of electrocardiography (ECG) gated multidetector computed tomography (MDCT) in preoperative assessment of DORV and its associated malformations, providing key anatomic parameters that affect surgical planning. Results A total of 50 patients diagnosed by echocardiography with DORV referred from our institute between September 2018 and August 2020 were enrolled. The location of the ventricular septal defect (VSD) to the great vessels and the alignment of the great vessels to each other as well as other associated malformations that affect the surgical planning were assessed by MDCT. The patients were retrospectively classified into subgroups according to the relative positions of the great arteries, the relationship between the great arteries and the VSD, and the presence of associated malformations according to the classification of Society of Thoracic Surgeons database. The diagnostic value of MDCT and transthoracic echocardiography (TTE) in evaluation of associated cardiac malformations apart from double outlet right ventricle was compared in 20 patients, whom surgeries were performed and surgical results were obtained. Fallot type of DORV was the most common clinical type which represented 48% of the patients in which the VSD is committed to the aorta. The second most common clinical type was Taussig–Bing anomaly which represented 30% of the patients and the VSD was seen committed to the pulmonary artery. The atrio-ventricular septal defect (AVSD)/uni-ventricular type represented 16% of the patients in the current study, with pulmonary and systemic venous anomalies, heterotaxy syndrome and situs anomalies were commonly associated. A total of 53 malformations apart from DORV were found in 20 patients whom performed surgical interventions. MDCT detected different vascular and situs anomalies in those patients with 100% sensitivity and 100% positive predictive value compared to 71.4% and 94% respectively in TTE. On the other hand, in our study TTE was superior to MDCT for detection of intracardiac anomalies with 100% sensitivity and 100% accuracy compared to 87.5% and 95% respectively in MDCT. Conclusions Our study suggested that ECG gated MDCT serves as a rapid, noninvasive imaging modality with good spatial resolution and provides excellent diagnostic image quality and has satisfactory diagnostic accuracy in the preoperative assessment of DORV. It is superior to echocardiography in providing a comprehensive mapping of the anatomy of complex anomalies especially that of extra-cardiac structures such as aorta, systemic veins, pulmonary veins, and pulmonary arteries. However, it can miss tiny intracardiac malformations. So combining the results of MDCT and echocardiography would be beneficial to guarantee the accuracy of diagnosis of DORV.