ABSTRACT
Diagnostic evaluation of disorders of the venous system has benefited from advances in state-of-the-art computed tomography (CT) and magnetic resonance imaging (MRI) applications. One additional distinct advantage of CT compared with MRI is the ability to demonstrate calcified densities such as calcified granulomatous lymph nodes as a cause of superior vena cava obstruction on pre-contrast acquisitions. A blood pool gadolinium-based MRI contrast agent has been introduced, with an intravascular half-life of approximately 30 minutes. Contrast-to-noise ratios of venous blood are significantly higher with MRI, although signal-to-noise ratios are occasionally lower. Magnetic resonance (MR) venography is preferred in patients with allergies to iodinated contrast or renal insufficiency. MR venography is also the test of choice in patients without venous access, since many non-contrast techniques are available with MRI. CT and MR are both effective tools for answering a large number of clinical questions regarding the venous system.
