Computed tomography of primary aortocaval fistula.

Spontaneous aortocaval fistula is a rare but documented complication of arteriosclerotic abdominal aortic aneurysm. Most cases reported have presented clinically with a palpable aneurysm, abdominal bruit, and high output congestive heart failure. A diagnosis in such cases requires active demonstration of findings secondary to arteriovenous shunting, which can be optimized utilizing proper CT bolus technique and dynamic scanning. We describe several CT findings--all of which may be typical for and support the diagnosis of this potentially lethal complication of abdominal aortic aneurysm.