Radiological Diagnosis of Portal/Mesenteric Vein Occlusion

BACKGROUND: In contrast to an acute occlusion of the visceral arteries, which is the most important differential diagnosis for an occlusion of the portal venous system and which poses a highly dangerous situation ending in gangrene of the bowel wall, the symptoms of an acute occlusion of the portal venous system are quite unspecific. To rule out an acute arterial occlusion, diagnostic evaluation has to be carried out quickly in order to decide on the necessity of therapeutic steps concerning a recanalization of the occluded vessels. Only few therapeutic options are available to recanalize and remodel the portal venous system, depending on the underlying disease, the age of the occlusion, its extension, and the effect on the bowel wall, stomach, spleen, and abdominal wall. Moreover, the efficacy of recanalization procedures mainly depends on the formation and number of collateral venous blood supply, its degree, and the anatomic structure. Possible complications of portal hypertension like varices, gastrointestinal vasculopathy, ascites, and splenomegaly also influence the success of recanalization procedures. Only in cases of acute thrombotic occlusion systemic lytic therapy promises to be successful. Therefore, other options such as transjugular intrahepatic recanalization, e.g. by means of the TIPS (transjugular intrahepatic portosystemic shunt) procedure, have to be evaluated. METHODS: Review of the literature. RESULTS: Noninvasive methods such as ultrasound (US), computed tomography, and especially magnetic resonance imaging (MRI) allow the evaluation of therapeutic options as well as their success, the feasibility of technical procedures, the detection of possible risks, and a calculation of risks and benefits. CONCLUSION: In order to arrive at the correct therapeutic decision, a combination of MRI and US methods combined with color Doppler guarantee the most efficient diagnostic results in cases with acute or chronic occlusions of the portal venous system.