Detection of perfusion areas of the gallbladder vein on computed tomography during arterial portography (CTAP)--the background for dual S4a.S5 hepatic subsegmentectomy in advanced gallbladder carcinoma.

Background/Aims: It has been speculated that the veins of the gallbladder join the intrahepatic portal veins supplying the Couinaud's S 4a -S 5 . This has been the theoretical ground for the resection of these 2 hepatic subsegments in advanced gallbladder carcinoma. However, no consensus has been reached on this concept. Methodology: The current study describes the non-neoplastic perfusion defects in connection with the gallbladder bed in 100 consecutive hepatic CTAP (computed tomographies during arterial portography). The suitability of S 4a and S 5 subsegmentectomies of the liver for advanced gallbladder carcinoma was also investigated by examining CTAP images of the branches of the portal vein involved in the perfusion defect. Results: Two types of gallbladder venous perfusion were observed: 1) sphenoid distribution from the gallbladder bed into the P 4a (37%), P 5 (52%) and P 6 (3%), and 2) perfusion into the P 4 (9%) or directly into the middle hepatic vein (9%) after communicating with the hepatic hilum at the dorsal side of S 4 . Conclusions: These results support liver resection at S4a and S5 as the surgical approach for cases of advanced gallbladder carcinoma.