Preoperative cholangiography of the caudate lobe: Surgical anatomy and staging for biliary carcinoma

The biliary branches of the caudate lobe (B1) join the right hepatic duct, the left hepatic duct, the confluence of these ducts, and/or the right posterior segmental bile duct. Therefore, in the preoperative staging of biliary tract carcinoma it is important to delineate the anatomy of B1 and the extent of cancer spread into B1. Tube cholangiography through percutaneous transhepatic biliary drainage or selective cholangiography by percutaneous transhepatic cholangioscopy enables us to obtain fine images of B1. We have developed cholangiography in the cephalad anterior oblique position to visualize B1 more clearly and distinctly. Four separate types of biliary branches are identified in the caudate lobe: (1) A duct running from the cranial portion of the right caudate lobe along the inferior vena cava to the hepatic hilus (B1r); (2) a duct from the cranial portion of the left caudate lobe to the hepatic hilus (B1ls); (3) a duct from the left lateral part of the left caudate lobe to the hepatic hilus (B1li); and (4) a duct from the caudate process to the hepatic hilus (B1c). The findings of the root of B1 in resected patients with biliary tract carcinoma were classified into four groups: not stenotic, short segmental stenosis, long segmental stenosis, and poorly imaged. A study of 64 branches of B1 in 42 resected patients with biliary tract cancer revealed carcinoma invasion in or near the root of B1 in all patients with poorly imaged or long segmental stenosis of B1, and in 33% of those with short segmental stenosis of B1.