RESUMEN
Objective To study the anatomical variations adjacent to the umbilical portion of the left portal vein (U-point) radiologically and to determine their impact on treatment of hilar cholangiocarcinoma (HCCA).Methods From January 2014 to February 2016,47 consecutive patients who were diagnosed to suffer from Bismuth type Ⅰ,Ⅱ or Ⅲ a HCCA in our institution were retrospectively studied.All these patients underwent enhanced CT examination preoperatively and three-dimensional (3D) models were then reconstructed.Results Any variations of the left biliary system in relation to the U-point were analyzed.The findings showed that:B2 and B3 united above or lateral to the U-point in 31 patients (65.9％);B2 and B3 united medial to the U-point in 4 patients (8.5％);and B4 converged into B3 prior to B2 in 6 patients (12.8％).Rare variations were observed in 6 patients (12.8％).For the confluence patterns of B4:the central type was found in 10 patients (21.3％),the peripheral type in 35 patients (74.5％) and the combined type in 2 patients (4.2％).Analysis of the relationship between B1l and the confluence of B2 and B3 showed the distance to be (31.6 ± 6.2) mm in the above or the lateral patterns and (13.7 ± 4.7) mm in the medial pattern.The difference was significant (P ＜0.05).The distance from B1l to B4 was (7.1 ± 2.0) mm in the central and combined types but (16.4 ±4.0) mm in the peripheral type.The difference was significant (P ＜ 0.05).The left hepatic artery showed variations in the origin and course pattern in 4 (8.5％) and 6 patients (12.8％),respectively.The two-dimensional (2D) and 3D imagings showed excellent consistency in the evaluation of variations of the left biliary system in relation to the U-point and the left hepatic artery.Conclusions It is very important to know the variations of the left biliary and the vascular systems adjacent to the U-point in preoperative evaluating on resectability of HCCA.An accurate assessment could be accomplished using 2D imaging alone.However,3D reconstruction is a useful technique to use in complex case with locally advanced tumors.