Inflammatory aortic aneurysm (periaortic fibrosis): radiologic imaging.

Inflammatory aneurysms represent a distinct surgical entity with a reported incidence varying from 5% to 23% of all abdominal aortic aneurysms. Surgical repair of inflammatory aneurysms is associated with a higher morbidity and mortality than is repair of simple aortic aneurysms. Complicated cases require suprarenal aortic control, and the surgeon must be forewarned to maximize the chance for successful aneurysm repair. Preoperative diagnosis of this entity by cross-sectional imaging facilitates improved planning of the operative approach and permits the institution of preoperative steroid treatment to reduce the volume of the periaortic fibrotic mass. Ultrasound demonstrates the inflammatory process as a hypoechoic mass surrounding the intensely echogenic, thickened aortic wall. Computed tomography reveals a thickened, often calcified aortic wall and a mass of periaortic inflammatory tissue. Dynamic scanning reveals rapid intraluminal enhancement, slightly delayed enhancement of the inflammatory mass, and nonenhancement of the thick fibrous adventitia.