Fig. 11
From: CT imaging features of atrioventricular shunts: what the radiologist must know
Four-chamber view (a) and short-axis (b) contrast-enhanced CT images showing a large OP defect (asterisk) allowing a communication between the left atrium (LA) and right atrium (RA). These defects are located in the part of the interatrial septum adjacent to the AV valves. Because OP defects are often large and lack a septal flap as in a patent foramen ovale, a shunt-induced volume overload with subsequent enlargement of the RA and ventricle can be seen