A comparison of computed tomography, magnetic resonance imaging, and digital subtraction angiography findings in the diagnosis of infected aortic aneurysm.

PURPOSE: To characterize imaging findings from computed tomography, magnetic resonance imaging, and angiogram in patients with infected aortic aneurysm.

METHODS: We retrospectively reviewed the records of 21 patients (men, 17; women, 4) with proven infected aortic aneurysms and compared the imaging findings (computed tomography scans, n = 21; magnetic resonance images, n = 2; and angiograms, n = 2).

RESULTS: Aneurysms were located in the descending thoracic aorta (n = 10; 47.6%), abdominal aorta (n = 6; 28.6%), aortic arch (n = 3; 14.3%), and thoracoabdominal aorta (n = 2; 9.5%). Aneurysms were saccular in 19 (90%) and fusiform in 2 (10%). Maximal diameters were greater than 10 cm in 2 patients (10%), 5 to 10 cm in 11 (52%), and less than 5 cm in 8 (38%). Average diameters were 6.5 cm in the aortic arch, 5.3 cm in the descending thoracic aorta, and 5.1 cm in the abdominal aorta. Obvious aortic wall calcification occurred in 19 patients (90%). Other features included disrupted calcification (n = 15; 71%), prominent and irregular wall thickening (n = 17; 81%), periaortic soft tissue mass (n = 15; 71%), rim enhancement (n = 18; 86%), periaortic gas (n = 7; 33%), periaortic stranding and fluid retention (n = 14; 67%), periaortic hematoma (n = 3; 14%), adjacent bone destruction (n = 1; 5%), pleural effusion (n = 12; 57%), and associated dissecting aneurysm (n = 2; 10%).

CONCLUSIONS: Saccular aneurysms, adjacent soft tissue masses, rim enhancement, stranding, fluid, gas, and unusual adjacent bony destruction highly suggest infected aneurysm.