A 76-year-old male presented to the emergency room with flank pain and a fever of 101°F. He was referred to the radiology department for noninfused CT angiography (CTA) to exclude nephrolithiasis.

Figure 25-1 Aortic infection with pseudoaneurysm formation. (A) Noninfused CT shows inflammation on the posterior wall (arrows) of the aorta. (B) Infused CT obtained 10 days later shows a saccular aneurysm with increased inflammation. (C) Frontal aortogram shows saccular aneurysm. (D) Lateral aortogram shows pseudoaneurysm to better advantage.

• Angiography is usually reserved for treatment planning or prior to endovascular therapy.
  
• The most common angiographic finding is a lobular, saccular aneurysm in the paravisceral location.

Aortic infection with juxtarenal saccular aneurysm formation.

The patient was taken to the operating room. The midabdominal aorta was resected and oversewn, and grafts were fashioned to the major visceral arteries. An axillobifemoral bypass graft was performed to provide arterial flow to the legs. The patient was placed on long-term antibiotics. Cultures of the resected specimen grew Salmonella.

Infected aneurysms or pseudoaneurysms of the aorta are rare. The classic triad of fever, pain, and pulsatile mass is found in fewer than half of affected patients. The term “mycotic aneurysm” is a misnomer as most infections are due to bacteria, not fungus. Salmonella is the most common causative agent of aortic infections; unlike most bacteria, Salmonella can invade the arterial intima. Staphylococcal aureus