Fig. 22

Atrial septal defect (ASD) with left to right shunt. a Sagittal MIP demonstrates a posterior left atrium (LA), with a more anterior right atrium (RA). The superior vena cava (SVC) is identified as it enters the right atrium. A jet of contrast material (arrowhead) extends from the left atrium through an ASD into the right atrium, just below the orifice of the SVC. The proximity of the ASD to the SVC is clearly demonstrated. b Axial MIP demonstrates the ASD with left to right shunting of contrast (arrowhead). The proximity of the ASD to the aortic root (Ao) is clearly demonstrated. The location of the ASD and the presence of a rim of tissue must be ascertained prior to attempted percutaneous closure. If the ASD is too close to the aortic root, the closure device may clamp the root with a possible long-term complication of erosion into the aortic root