Imaging of the Portal Venous System

3D CE MR portography is regarded as a safe, quick and robust imaging modality for evaluation of the portal-venous system. This technique has been shown to be advantageous compared to currently used techniques such as ultrasonography, catheter angiography, computed tomography (CT), and non-enhanced MR angiography with TOF and phase contrast (PC) techniques [22].

There are no major differences between MRA of the abdominal arterial system and MR portog-raphy in terms of patient management, coil selection and MR sequences. After acquisition of a pre-contrast coronal 3D gradient echo dataset, contrast agent is injected and image acquisition commences. Typically, image acquisition on MR por-tography is timed to the arterial vessel system with an additional acquisition delay of 40-60 sec after contrast agent injection prior to acquisition of the portal-venous dataset. At post-processing, the pre-contrast and CE arterial phase datasets are subtracted from the portal-venous phase dataset to enable visualization of the portal-venous system without arterial overlay. MIP reconstruction and multiplanar reformation techniques permit accurate evaluation of the portal-venous system.

The simultaneous availability of coronal source images permits demonstration of parenchymal lesions of the liver, pancreas, biliary tract and spleen. Precise and reliable assessment of the portal-venous system in patients with hepatic cirrhosis and portal hypertension is essential before liver transplantation, non-surgical transjugular shunting or surgical portosystemic shunting. In patients with portal hypertension and a history of gastro-esophageal bleeding, it is mandatory to ascertain whether the portal-venous system is patent or if the portal vein or its main branches are throm-bosed [28].

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Blood Pressure Health

Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...

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