title: Study on the segmentation of the right anterior sector of the liver.
abstract: The segmentation of the right anterior sector of the liver still is debatable due to the lack of an anatomic landmark of the boundary between Couinaud segments V and VIII (cranio-caudal segmentation). Some authors have proposed the concept of a ventro-dorsal segmentation. The aim of this study was to evaluate which concept of segmentation better reflects the anatomy.
  
  
  
  Using 3-dimensional computed tomography software, the ramification pattern of the right anterior portal vein was examined in 100 patients. A thick, hepatic, venous branch that passes through Couinaud segment VIII was termed V8, and its course was investigated using a virtual hepatectomy.
  
  
  
  Regarding the anatomy of the portal vein in the right anterior sector, the cranio-caudal type was found in 53 patients, the ventro-dorsal type in 23 patients, and the trifurcation type in 13 patients. The remaining 11 patients had miscellaneous patterns of ramification. In the cranio-caudal type, the volume of the cranial segment was greater (P < .001) than that of the caudal segment. In the ventro-dorsal type, the volume of the ventral segment was greater (P = .007) than that of the dorsal segment. The V8 was identified in 81 of the 89 (91%) patients analyzed. The proportion of cases in which the V8 functioned as a landmark of the border between the ventral and dorsal segments was 63% (56/89 patients).
  
  
  
  Regarding the segmentation of the right anterior sector of the liver, the cranio-caudal segmentation introduced by Couinaud is dominant (53%), while ventro-dorsal segmentation is less common (23%). Therefore, universalization of the concept of the ventro-dorsal segmentation is unrealistic.
authors.affiliation: Division of Surgical Oncology, Department of Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Tomoki
authors.initials: T
authors.lastname: Kobayashi
authors.affiliation: Division of Surgical Oncology, Department of Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Tomoki
authors.initials: T
authors.lastname: Ebata
authors.affiliation: Division of Surgical Oncology, Department of Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Yokoyama
authors.affiliation: Division of Surgical Oncology, Department of Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Igami
authors.affiliation: Division of Surgical Oncology, Department of Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Gen
authors.initials: G
authors.lastname: Sugawara
authors.affiliation: Division of Surgical Oncology, Department of Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Mizuno
authors.affiliation: Division of Surgical Oncology, Department of Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Junpei
authors.initials: J
authors.lastname: Yamaguchi
authors.affiliation: Division of Surgical Oncology, Department of Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan. Electronic address: nagino@med.nagoya-u.ac.jp.
authors.forename: Masato
authors.initials: M
authors.lastname: Nagino
mesh_terms: D000328:Adult; D000368:Aged; D001650:Bile Duct Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D018281:Cholangiocarcinoma / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D015331:Cohort Studies; D005260:Female; D006498:Hepatectomy / Q000379:methods*; D006801:Humans; D021621:Imaging, Three-Dimensional; D008099:Liver / Q000000981:diagnostic imaging* / Q000601:surgery; D008113:Liver Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography / Q000379:methods; D011169:Portal Vein / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000601:surgery; D018570:Risk Assessment; D016896:Treatment Outcome