Diagnosis of aortoenteric fistulas with CT angiography

To describe the diagnostic findings of primary and secondary aortoenteric fistulas (AEFs) at computed tomographic (CT) angiography in a cohort of patients known to have AEF and to correlate those findings with those from endoscopic gastroduodenoscopy (EGD) and surgery.

CT angiography was performed in nine patients with AEF. There were four men and five women aged 43-85 years (mean age, 67 years). All CT angiograms were retrospectively reviewed for signs of AEF. Reports from EGD, surgery, and pathologic examination were also reviewed.

One patient had a primary AEF, and eight patients had a secondary AEF. Findings at CT angiography were suggestive of the diagnosis in all nine patients. The two definitive CT angiographic findings were identification of the graft within the bowel lumen in two patients (22%) and active extravasation in one patient (11%), allowing the definitive diagnosis in three of the nine patients (33%). Secondary signs, which helped predict the high likelihood of the diagnosis but could also be seen in graft infection or inflammation without AEF, were as follows (in descending order of frequency): effacement of the periaortic or perigraft fat plane and the fat plane between the aorta and bowel (nine patients, 100%), perigraft soft tissue (nine patients, 100%), bowel wall thickening adjacent to the graft (eight patients, 89%), perigraft fluid (seven patients, 78%), perigraft hematoma (six patients, 67%), pseudoaneurysm or aneurysm bulge (six patients, 67%), ectopic gas (five patients, 56%), and dystrophic vascular graft calcification (one patient, 11%). The diagnosis was confirmed surgically in seven patients and with clinical follow-up in two.

CT angiography is well suited for helping make or suggesting the diagnosis of AEF and is potentially more accurate than EGD.