Portal vein patency

Later phase imaging is necessary to detect other less vascular lesions, the degree of multifocality, and to identify portal vein patency. MRl is also a sensitive modality to identify and characterize lesions, given specific attention to diffusion weighted imaging sequences. 

CT/MRI scan of the abdomen and pelvis with assessment of portal vein patency... 

All patients undergo analysis of baseline liver function, electrolytes, renal function, complete blood count, and coagulation studies within 1-4 weeks prior to the procedure. CT or MRI is performed prior to treatment primarily for assessment of portal vein patency and to document lesion size and distribution. 

Splenoportographic procedures allow an accurate depiction of the portal vein and its afferent flow areas. Despite the development of new techniques, these methods are of importance in clarifying the cause of portal hypertension, and they are (still) deemed to be a prerequisite for operations aimed at reducing the pressure and vol-mne in the portal venous circulation. Vessels with a diameter of <1 cm are unsuitable for long-term patency of a shunt. Direct and indirect procedures are available. (16, 35)... 

Indirect splenoportography via the femoral artery is not only very important, but also low-risk. (s. p. 182) Using radiography, the arterial branches of the abdominal aorta initially become visible, followed by the spleen, the splenic vein and the portal vein together with its afferent veins and collaterals. This procedure provides information on (7.) localization of vascular resistance-related hypertension, (2.) cause of portal hypertension (in individual cases), (3.) patency and diameter of the respective vessel, 4.) extent of collateral circulation, (5.) hepatopetal or hepatofugal direction of flow in the portal vein, and 6.) shunt capacity of the splenic vein or superior mesenteric vein. (s. p. 182)... 

Patency of the portal vein should be assessed, as portal vein thrombosis may occur in patients with end-stage cirrhosis. Portal vein thrombosis is not a contraindication to liver transplant, but requires modification of the surgical technique to create extra-anatomical venous grafts (Fig. 4.2.11). 

The patency of hepatic veins and the inferior vena cava should be evaluated. Transjugular intrahepatic portal-systemic shunts (TIPS), when present, should be assessed for patency and their location should be described (Fig. 4.2.13). The distal end of the TIPS should be in the right hepatic vein when being positioned in the inferior vena cava it constitutes a contraindication to liver transplantation. 

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