CT imaging features of AAA rupture and impending rupture
AAA rupture most commonly occurs along the posterolateral aspect of the abdominal aorta and is 2 to 4 times more common in women than in men. CT findings of AAA rupture include periaortic and retroperitoneal hemorrhage, sometimes with hemoperitoneum, and active arterial hemorrhage, as described above. Other imaging findings of rupture or impending rupture include high attenuation hemorrhage within the thrombus or wall of an AAA (“crescent” sign); interruption or outward displacement of atherosclerotic calcification, irregular contour, or defect of the aortic wall at the site of rupture; abnormal shape of an AAA; poor visualization of the posterior wall of an AAA that follows the vertebral contour of the spine (“draped aorta” sign); large size (up to 20% of AAA >5 cm rupture within 5 years); and rapid increase in the size of an AAA
