Abdominal Aortic Aneurysm (AAA)

Left Image: Abdominal axial CT with contrast demonstrating a large AAA with extensive intraluminal thrombosis.  Patent central lumen containing contrast surrounded by thrombus peripherally.  Aortic wall evident due to circumferential calcification (atherosclerosis).
 
Right Image: Abdominal axial CT with contrast showing abdominal aorta of normal diameter.
[Courtesy of Dr. N. Jaffer]