Sinus Venosus Atrial Septal Defect in Adults: Utility of Cardiovascular MRI in resolving this Diagnostic Dilemma

Sinus venosus atrial septal defect (SV-ASD) can be a challenging diagnostic problem. It can present with non-specific signs and symptoms and, on imaging, can mimic other causes of right heart dilatation. Transthoracic echocardiography using standard scan planes may be limited, due to the defect and any associated anomalous pulmonary venous drainage lying outside the confines of the fossa ovalis. At our institution, we use cardiovascular magnetic resonance imaging (CMRI) as a problem-solving tool in these patients. In this article, we discuss the utility of CMRI in establishing the diagnosis by presenting our recent experience and illustrating it with sample cases. We wish to highlight the problems relating to making a diagnosis of SV-ASD in adult patients, and how CMRI has contributed to overcoming these in our practice.