Abstract
The route, distribution and clearance of intraarterially administered Lipiodol in the liver has been the subject of much speculation. The hepatic microcirculation was therefore studied by in vivo microscopy after injection of Lipiodol into the hepatic artery and the portal vein in rats. After intraarterial injection, Lipiodol rapidly entered the portal branches through arterio-portal communications. Lipiodol also passed through the sinusoids from the portal into the hepatic veins and then into the systemic circulation. Sinusoidal congestion occurred when the oil droplets filled the liver microcirculation and resolved as the oil was cleared. It is of clinical significance to note the passage of the oil into the systemic circulation after arterial injection.