Portal vein thrombosis: imaging features and associated etiologies.

Thrombosis of the portal vein and its splanchnic tributaries is often unsuspected clinically and may be recognized only after imaging studies of the abdomen are performed for other reasons. Radiologists should be aware of the clinical situations that predispose a patient to portal or mesenteric vein thrombosis and should also be able to recognize the sequelae of chronic thrombosis. Different modalities can be used to image the patient with portal vein thrombosis; each has its strengths and drawbacks. This paper discusses the conditions that predispose to portal and mesenteric vein thrombosis, differentiating intrahepatic portal vein occlusion secondary to liver disease from extrahepatic portal vein occlusion associated with a normal liver. The imaging features of portal vein thrombosis, its associated causes and sequelae will be reviewed as demonstrated on computed tomography (CT), ultrasound, magnetic resonance imaging (MRI), angiography, and plain film.