Conventional and Cross-Sectional Venography

Conventional venography has long been considered the gold standard for evaluation of the venous system. This exam is performed in an angiography suite using real-time X-ray imaging (fluoroscopy) to visualize intravenously injected iodinated contrast media. Digital subtraction angiography (DSA) is a technique that allows depiction of only the venous structures of interest by “subtracting” out the nonvascular structures, such as bone. This greatly improves visualization of intravascular contrast material. Cross-sectional venography, comprised of CT venography and MR venography, has the unique advantage of allowing visualization of any obstructing masses or other extrinsic structures that impact the venous system. The entire central venous system can be evaluated by injection through a central venous catheter or a single peripheral IV at any site using indirect imaging. MRV is the preferred method for evaluation of the central veins because the excellent signal intensity generated by gadolinium agents allows excellent visualization with indirect injection. With time-resolved MRA, the contrast bolus can be visualized passing through the vasculature in real-time manner, which allows excellent evaluation of collateral veins and routes of preferential blood flow. High-spatial resolution imaging can also be performed, allowing accurate characterization of lesions. This chapter discusses conventional and cross-sectional venography with a focus on particular disease processes.