Aortogram and CT scan of infrarenal abdominal aortic aneurysm

The digital subtraction aortogram (A) shows a fusiform AAA (arrow). The contrast column shows the luminal diameter and not the true diameter of the aneurysm. Aortic diameter is best evaluated on cross-sectional CT, which shows the outside margin of the aortic wall (B). Note that there is a large amount of eccentric, mural thrombus within the aorta (arrow) on the CT scan. Also, a horseshoe kidney is quite obvious on the CT scan (arrowhead) but is only vaguely outlined on the arteriogram (black arrows in panel A). The presence of a horseshoe kidney may alter the approach to AAA repair.