During the last 25 years, there have been important developments in visualising the portal vein, in examining its contents, and in measuring the pressure of blood flowing within it. Radiologists have set the scene and now is the time of the scanner. These technical advances have been applied to the diagnosis and treatment of patients with portal hypertension, and many ingenious surgical techniques have been proposed. The problem of successful treatment of the patient with bleeding oesophageal varices and cirrhosis of the liver, however, has not yet been solved. This report discusses the portal vein in terms of pressure, flow, and regeneration factors. Portal hypertension is classified and methods of relief are discussed. Methods of visualising the portal vein RADIOLOGICAL TECHNIQUES Peroperative injection of contrast material directly into portal vein or one of its tributaries This method has the obvious disadvantage of necessitating surgery. Filling of the portal system can be so great that interpretation of anatomy is difficult. Splenic venography This is simple to perform. The portal system and collaterals are seen particularly clearly and the portal pressure can be measured at the same time through the splenic needle. The small risk of haemorrhage from the splenic puncture is a disadvantage. Abnormal blood clotting or deep jaundice are contraindications. .Selective visceral angiography The coeliac axis is catheterised via the femoral artery with a pre-formed opaque catheter and the injection of a bolus of radio-opaque contrast material'. The portion of contrast material that flows into the splenic artery returns through the splenic and portal veins and produces a splenic and portal venogram of variable quality. Similarly, a bolus of contrast material introduced into the superior mesenteric artery returns through the superior mesenteric and portal vein, which can be seen in radiographs exposed at the appropriate intervals. The portal vascular bed is not seen so clearly as with splenic venography. Because splenic venous blood may be diverted into large gastro-oesophageal collaterals a splenic venogram may occasionally show a non-filled portal vein, even though the vein is patent. In such cases, a mesen-70
