An artery is considered aneurysmal when its size is 50% larger than (or 1.5 times) the normal native artery diameter. Iliac artery aneurysms are found in about 25% of patients with an abdominal aortic aneurysm (AAA); however, the overall prevalence of iliac artery aneurysms in the adult population is just 1%, even when associated with AAA.