Extrahepatic blood supply to hepatocellular carcinoma – a pictorial essay

Transarterial chemoembolization is a standard locoregional therapy for intermediate stage hepatocellular carcinoma. The tumour is typically supplied by the hepatic arteries, however, extrahepatic collateral arteries may significantly contribute parasitic blood supply to the tumour. Large and exophytic tumour, subcapsular location, direct invasion and adhesion to adjacent organs, hepatic artery dissection, stenosis and occlusion resulting from multiple embolizations are risk factors of extrahepatic collateral arteries. Understanding the prevalence and prediction of these parasitic supplies on pre-procedural imaging is of utmost importance for optimizing technical and clinical outcomes.