Abdominal aortic aneurysm
- Adominal aortic aneurysms (AAA) are segmental dilatations of the aortic wall that cause the vessel to be larger than 1.5 times its normal diameter or that cause the distal aorta to exceed 3 cm.
- These can continue to expand and rupture spontaneously, exsanguinate, and cause death.
- The diameter of an aneurysm is directly related to its risk of rupture.
- For aneurysms smaller than 4 cm in diameter, the risk of rupture is less than 10%.
- Once an aneurysm is 4-5 cm in diameter, the risk of rupture increases to almost 25%, with an associated mortality rate as high as 75%.
- The accepted surgical mortality rate remains less than 5% with the elective repair of these 4- to 5-cm aneurysms.
- Approximately one third of AAAs originate close to or at the level of the renal arteries, and suprarenal involvement has been reported in as many as 10% of patients.
- The morphologic features, including the maximum diameter in both the anteroposterior and transverse dimensions and the length of the aneurysm, should be reported.
- The shape of the aneurysm (fusiform or saccular) and its relationship to branch vessels should also be described.
 Imaging Findings
Patient #1: CT images demonstrate a large abdominal aortic aneurysm
Patient #2: CT images demonstrate a large abdominal aortic aneurysm