Imaging and radiological interventions in extra-hepatic portal vein obstruction

Abstract

Extrahepatic portal vein obstruction (EHPVO) is a primary vascular condition characterized by chronic long standing blockage and cavernous transformation of portal vein with or without additional involvement of intrahepatic branches, splenic or superior mesenteric vein. Patients generally present in childhood with multiple episodes of variceal bleed and EHPVO is the predominant cause of paediatric portal hypertension (PHT) in developing countries. It is a pre-hepatic type of PHT in which liver functions and morphology are preserved till late. Characteristic imaging findings include multiple parabiliary venous collaterals which form to bypass the obstructed portal vein with resultant changes in biliary tree termed portal biliopathy or portal cavernoma cholangiopathy. Ultrasound with Doppler, computed tomography, magnetic resonance cholangiography and magnetic resonance portovenography are non-invasive techniques which can provide a comprehensive analysis of degree and extent of EHPVO, collaterals and bile duct abnormalities. These can also be used to assess in surgical planning as well screening for shunt patency in post-operative patients. The multitude of changes and complications seen in EHPVO can be addressed by various radiological interventional procedures. The myriad of symptoms arising secondary to vascular, biliary, visceral and neurocognitive changes in EHPVO can be managed by various radiological interventions like transjugular intra-hepatic portosystemic shunt, percutaneous transhepatic biliary drainage, partial splenic embolization, balloon occluded retrograde obliteration of portosystemic shunt (PSS) and revision of PSS.

Keywords: Extrahepatic portal venous obstruction; Portal cavernoma; Portal hypertension; Transjugular intrahepatic portosystemic shunt; Splenic embolization

Core tip: The present review describes the etiopathogenesis and role of imaging modalities in Extra-hepatic portal vein obstruction and role of various radiological interventional procedures in its management. The advantages and potential limitations of each imaging modality namely endoscopic retrograde cholangiography, ultrasonography and Doppler, multidetector computed tomography, magnetic resonance cholangiography and portovenography, endoscopic ultrasound and ultrasound transient elastography are discussed. Also, the concepts behind the use of interventional procedures like transjugular intra-hepatic portosystemic shunt, percutaneous transhepatic biliary drainage, partial splenic embolization, splenic artery aneurysmal embolization, balloon occluded retrograde obliteration of portosystemic shunt, etc., are described.