After multiple hepatic artery embolization, the original arterial blood supply of hepatocellular carcinoma is reduced or disappeared, and collateral circulation will certainly be established. If there is a lack or scarcity of local hepatic arterial vessels or a bias of iodine oil deposition in the tumor, the possibility of collateral circulation formation should be considered and other vessels should be explored. There are many types of collateral circulation in hepatocellular carcinoma, which are classified as follows: intrahepatic collateral circulation: there are two types: intrahepatic lobe and interhepatic lobe. The former shows abundant reticular vessels connecting to the occluded hepatic artery branches, while the latter shows thickening of the arteries in the adjacent liver lobe, feeding the lesion through the side branches of the original interlobular artery or the tumor directly feeding from the branches of the adjacent hepatic lobe artery. Extrahepatic collateral circulation: It can come from the abdominal arterial system, such as gastroduodenal artery, common hepatic artery, omental artery, left or right gastric artery, dorsal pancreatic artery, etc.; left and right subphrenic arteries; superior mesenteric artery system, commonly via inferior pancreaticoduodenal artery → superior pancreaticoduodenal artery → gastroduodenal artery → intrinsic hepatic artery, which is the supply via the pancreatic arch artery, commonly due to occlusion or valvular occlusion of common hepatic artery; other The arteries of the pancreatic arch are commonly occluded by the common hepatic artery or valvular occlusion; others: such as intercostal artery, right renal artery, adrenal artery, etc. Feeding from the mesocolic artery has also been reported.