Inflammatory aneurysms of the abdominal aorta: CT findings

Inflammatory aneurysm of the abdominal aorta (IAAA) is a variant of atherosclerotic aneurysm that is characterized by inflammatory and/or fibrotic changes in the periaortic regions of the retroperitoneum [1, 2]. These inflammatory and/or fibrotic changes are probably the result of a local autoallergic reaction to certain components of atherosclerotic plaques [2]. This distinct entity has important implications, as the periaortic fibrotic tissue adherent to ureters, the duodenum, and the inferior vena cava may complicate surgical repair [1, 2]. The purpose of this essay is to illustrate the CT appearance of IAAA, with emphasis on the identification of IAAA and differentiation from conventional aortic aneurysms, evaluation of the involvement of adjacent structures by the periaortic fibrosis, and evaluation of the retroperitoneum after aneurysmal repair to analyze the resolution or the persistence of the periaortic fibrosis.