Angiographic Anatomy and Relevance of 3 and 9 O’clock Arteries During Radioembolization

Selective Chemoembolization of Caudate Lobe Hepatocellular Carcinoma: Anatomy and Procedural Techniques

Transarterial chemoembolization is the most common treatment for unresectable hepatocellular carcinomas (HCCs). However, when an HCC is located in the caudate lobe, many interventional radiologists are reluctant to perform chemoembolization and percutaneous ablation owing to the tumor's complex vascular supply and deep location. With the advent of C-arm CT, rendering the three-dimensional display of the hepatic artery and detecting the tumor-feeding vessels are possible and can help guide interventional radiologists to the tumor. The common origins of the caudate artery include the right hepatic artery, left hepatic artery, right anterior hepatic artery, and right posterior hepatic artery. The origins of the tumor-feeding arteries of a caudate lobe HCC can vary depending on the tumor's subsegmental location. Caudate lobe HCCs are commonly fed by multiple caudate arteries that are connected. In addition, extrahepatic collateral arteries frequently supply recurrent tumors in the caudate lobe. The caudate artery can supply portal vein thrombi or biliary tumor thrombi in patients with HCC. Several techniques such as preshaping the microcatheter or using the shepherd's hook technique are needed to catheterize the caudate artery in complex cases. Although uncommon, bile duct stricture is a serious complication following selective chemoembolization through the caudate artery. Identification and catheterization of the caudate artery have become possible in most patients by using C-arm CT and a fine microcatheter system, respectively. The authors review the anatomy of the caudate artery with C-arm CT and describe basic technical considerations in selective chemoembolization for caudate lobe HCCs. Unusual circumstances that require catheterization and techniques used for catheterizing the caudate artery are also described. Online supplemental material is available for this article. ^©RSNA, 2019.