title: Reappraisal of right portal segmental ramification based on 3-dimensional volume rendering of computed tomography during arterial portography.
abstract: OBJECTIVE
  To investigate and describe the segmental ramification patterns of the right portal vein (RPV) according to the Couinaud system.
  
  
  METHODS
  Between February 2004 and June 2005, 127 patients with hepatic tumors underwent computed tomography during arterial portography with a 16-slice multidetector computed tomography. The final analysis included 90 patients without RPV thrombosis or obvious vascular distortion. The ramification patterns of RPV were verified by 3-dimensional portograms using volume-rendering technique.
  
  
  RESULTS
  Seventy-five patients (83.3%) had bifurcation of the main portal vein, 12 (13.3%) had trifurcation, and 3 (3.3%) had the right posterior portal vein (RPPV) arising from main portal vein. A total of 5 segmental types and 3 subsegmental subgroups of RPV ramification patterns were clarified: type I, the classic ramification pattern with right anterior portal vein (RAPV) branching to S8/S5 and RPPV branching to S7/S6 (63; 70%); II, two separate segmental branches to S7 and S6 without a definite main stem of RPPV (18; 20%); III, "whisk-like" ramification pattern of RPV (2; 2.2%); IV, RAPV branching to S8 alone and RPPV to S5, S6, and S7, consecutively (5; 5.6%); and V, RPV first branching to S8/S5 and then to S7/S6 after a common path (2; 2.2%); subgroup a with dorsocranially directed branches arising from P8 and supplying S8 posterior to the right hepatic vein (28; 31.1%); subgroup b with RPPV branching to the dorsal part of S5 (11; 12.2%); and subgroup a + b, combination of the aforementioned 2 subgroups (45; 50%). In most patients, RAPV had dorsocranially directed branches posterior to the right hepatic vein (73; 81.1%), and RPPV gave off branches to the dorsal part of S5 (56; 62.2%).
  
  
  CONCLUSIONS
  Recognition of these ramification patterns could be helpful for more accurate anatomical resection of right hemiliver and preoperative planning, although some variants are present.
authors.affiliation: Department of Radiology, Taipei Veterans General Hospital, Taipei, Taiwan.
authors.forename: Te-Chang
authors.initials: TC
authors.lastname: Wu
authors.forename: Rheun-Chuan
authors.initials: RC
authors.lastname: Lee
authors.forename: Gar-Yang
authors.initials: GY
authors.lastname: Chau
authors.forename: Jen-Huey
authors.initials: JH
authors.lastname: Chiang
authors.forename: Cheng-Yen
authors.initials: CY
authors.lastname: Chang
mesh_terms: D000328:Adult; D000368:Aged; D003287:Contrast Media; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D007472:Iohexol / Q000031:analogs & derivatives; D008113:Liver Neoplasms / Q000098:blood supply / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011169:Portal Vein / Q000000981:diagnostic imaging*; D011172:Portography / Q000379:methods*; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
chemical_list: D003287:Contrast Media; D007472:Iohexol; C038192:iopromide