Infected Aneurysm Complicated with AV Fistula and Thrombosis of the Iliac Veins and Inferior Vena Cava: a case demonstrated with Computed Tomography

Reprint requests to: Dr. Tzu-Lung Ho Department of Radiology, Kuang Tien General Hospital. No.117, Shatian Road, Shalu, Taichung 433, Taiwan, R.O.C. Infected aneurysm of the abdominal artery has been found occasionally, but being accompanied with arteriovenous fistula detected by CT angiography has rarely been reported. A preoperative clinical diagnosis of infected aneurysm and arteriovenous fistula is difficult. We report a case of infected aneurysm of right common iliac artery, with the complication of arteriovenous f istula, causing thrombosis of the bilateral iliac veins and inferior vena cava. This case showed the periarterial abscess extension with partial thrombosis of iliac veins and inferior vena cava, which was not mentioned before in the literature. A contrastenhanced 64-row multiple detector CT scan with three-dimensional CT angiography is an effective, non-invasive method to detect the presence of aneurysm and its associated complications. Infected aneurysm is an infectious break in the wall of an artery with the formation of a blind, saccular outpouching that is contiguous with the arterial lumen [1]. Early detection of infected aneurysms is critical for effective treatment. Delayed t reatment of infected aneurysms of ten leads to sepsis, ar ter ial r upture, and death. Tradit ional investigations such as ultrasonography or a plain film radiography study are not effective for early diagnosis. Angiography is a more invasive diagnostic method, and the procedure has a relative high risk of aneurysm rupture. Computed tomography (CT) is the preferred imaging modality because it is widely available, fast and able to depict associated imaging details, such as gas and periaortic findings [2]. CT angiography by 64-row multiple detector CT (64-row MDCT) is a vascular imaging technique made clinically feasible by the combination of isotropic, high resolution imaging, fast rotation time, and wide scan coverage to provide a volume image during a single breath hold, which allows high-quality postprocessing of the three-dimensional (3D) image [3]. In this case report, the presence of peri-arterial abscess leading to partial thrombosis of iliac veins and inferior vena cava was not mentioned before in the literature. The infected aneurysm of right common iliac artery and its complications can be clearly identified by the 64-row MDCT reconstruction images.