Aortoenteric fistula: a diagnostic dilemma

Objective To assess the sensitivity and specificity of computed tomography (CT) in the diagnosis of aortoenteric fistula (AEF) and to determine the most accurate CT signs of the disease. Methods Hospital records were reviewed over a 20-year period. Twenty-three patients in whom a final diagnosis of AEF was made at laparotomy or autopsy were identified. Ten of these had CT performed. Twelve control cases were also collected. The 22 cases, (10 cases of AEF and 12 controls), were reviewed retrospectively by two independent readers, who were blinded to the clinical features and outcome. Each case was examined for six specific radiological findings. The outcome of other adopted investigative modalities was also examined. Results The presence of peri-aortic ectopic gas (>2 weeks following surgery) in the context of gastrointestinal (GI) blood loss was 100% specific for AEF. If AEF was considered to be present where signs of peri-aortic infection were present in a patient with GI bleeding, CT had an overall specificity of 100% (95% confidence interval = 1.0–1.0) and sensitivity of 50%. Conclusion CT can rule in the diagnosis of AEF but cannot rule it out. CT is recommended as the first-line investigation in a stable patient with suspected AEF.