Diagnosis of a porto-azygous shunt using helical computed tomography angiography.

Congenital portosystemic shunts occur uncommonly in dogs. Conventional diagnostic methods either do not offer simultaneous diagnosis and anatomic characterization or require an invasive selective catheterization. Helical computed tomography (HCT) is a rapid, noninvasive means of acquiring cross-sectional images of any portion of the body. Combined with a peripheral venous injection of contrast medium, HCT can produce computer-rendered, "angiogram-like" images of vasculature. These computer-generated multiplanar and three-dimensional HCT angiographic images were helpful in the diagnosis and accurate anatomic characterization of a porto-azygous shunt. A brief discussion of scanner and contrast medium protocol considerations necessary to achieve adequate vascular opacification for volumetric data reconstructions and diagnosis are outlined.