Diagnosis of aortocaval fistula by computed tomography

A case of an aortocaval fistula documented by contrast-enhancement computed tomography is reported. In the presence of a large abdominal aortic aneurysm, the computed tomography (CT) triad findings of: (1) vena caval effacement, (2) loss of the fat plane between the aorta and vena cava, and (3) rapid flow of contrast from the aorta into a dilated inferior vena cava is characteristic of an aortocaval fistula.

Magnetic resonance angiography in the preoperative evaluation of abdominal aortic aneurysms

Magnetic resonance angiography (MRA) and magnetic resonance imaging (MRI) are noninvasive techniques of visualizing blood vessels without the use of intravenous contrast or ionizing radiation. This prospective study assessed preoperative MRA and MRI in the evaluation of 28 patients with abdominal aortic aneurysm (AAA). MRI and MRA accurately predicted the extent of cephalad AAA, the patency of the superior mesenteric artery, and the course of the left renal vein, but were less accurate in defining the extent of caudal AAA, flow of the inferior mesenteric artery, and multiple renal arteries. This study suggests that MRI and MRA are alternatives to the combination of angiography and computed tomographic scan in the preoperative evaluation of patients with suspected AAA and no evidence of mesenteric or renal ischemia. When combined with preoperative segmental Doppler arterial studies, an accurate surgical plan may be formulated. Further refinements in image acquisition and postprocessing software analysis will advance the use of MRI and MRA for complete evaluation prior to elective AAA repair.