Review and illustrate the imaging findings in acute rupture and impending rupture of abdominal aortic aneurysms.

An abdominal aortic aneurysm (AAA) is a focal dilatation of the aorta measuring at least 3 cm in maximal diameter or ≥1.5 times the normal proximal diameter. The great majority are true aneurysms (focal bulging that includes all layers of the aortic wall). Pseudoaneurysms or false aneurysms are only contained by the outermost layer, the adventicia, and although are more commonly associated with rupture, they are rarer and usually occur in the setting of trauma. AAA can also be classified based on morphology as either...

In most cases, the aneurysm ruptures along its posterolateral border into the retroperitoneum, causing a retroperitoneal hematoma adjacent to the aneurysm [2, 5, 5] (Fig. 1and Fig. 2). When the rupture is subtler, only stranding of the fat adjacent to AAA may be seen. When large, the hematoma fills the perirenal and pararenal spaces and displaces the kidneys anteriorly or laterally. Haemorrhage directly to the peritoneal cavity can also occur as can, although very rarely, haemorrhage into the gastrointestinal tract (Fig. 3) or the inferior...

Knowledge of the CT features of aneurysmal rupture and impending rupture should be of primary concern to the radiologist, since its tremendous impact on patient outcome. Frank ruptured AAA carry a worrisome prognosis and when identified on CT should prompt rapid surgical intervention. The draped aorta sign and the imaging features of impending rupture should be looked for in patients with AAA, since these could be indications for aneurysmal repair before frank rupture ensues.

C. Lech, A. Swaminathan, Abdominal Aortic Emergencies, Emerg. Med. Clin. North Am. 35 (2017) 847–867. doi:10.1016/j.emc.2017.07.003. D. Rakita, A. Newatia, J.J. Hines, D.N. Siegel, B. Friedman, Spectrum of CT Findings in Rupture and Impending Rupture of Abdominal Aortic Aneurysms, Radiographics. 27 (2007) 497–507. doi:10.1148/rg.272065026. F. Parkinson, S. Ferguson, P. Lewis, I.M. Williams, C.P. Twine, Rupture rates of untreated large abdominal aortic aneurysms in patients unfit for elective repair, J. Vasc. Surg. 61 (2015) 1606–1612. doi:10.1016/j.jvs.2014.10.023. E.L. Chaikof, D.C. Brewster, R.L. Dalman, M.S. Makaroun, K.A. Illig,...