Radiology of Liver Circulation

The liver blood flow disorders are usually described under the term 'portal hypertension', which is a well­ known syndrome since it has been widely studied for years from a clinical, radiological and therapeutic point of view. In fact, portal hypertension is only the result of an obstacle to the portal flow, the clinical manifestations of which often occur at a late stage of the disease: bleeding esophageal varices, splenomegaly, ascites. In addition, it is well known that there is not always a precise relationship between the degree of the obstruction, i.e. the decrease of the portal inflow and the level of the portal hypertension. A severe obstruction to the portal flow may therefore sometimes remain clinically inconspicuous for a long time. For this reason improvement of our knowledge of portal hypertension mainly relies on angiographic investigations. Thus, splenoportography permits the discovery of prehepatic obstructions whereas hepa­ tic venography permitted the recognition of two different types of intrahepatic obstruction according to the pre-sinusoidal or post -sinusoidal site of the obstacle. More recently, arterial hepatic changes could be evidenced through arteriography. However, these angiographic investigations have not yet allowed for all the problems about portal hypertension to be clearly identified.