title: Portal vein branching order helps in the recognition of anomalous right-sided round ligament: common features and variations in portal vein anatomy.
abstract: This study aimed to evaluate the common features and variations of portal vein anatomy in right-sided round ligament (RSRL), which can help propose a method to detect and diagnose this anomaly.
  
  
  
  In this retrospective study of 14 patients with RSRL, the branching order of the portal tree was analyzed, with special focus on the relationship between the dorsal branch of the right anterior segmental portal vein (PA-D) and the lateral segmental portal vein (PLL), to determine the common features. The configuration of the portal vein from the main portal trunk to the right umbilical portion (RUP), the inclination of the RUP, and the number and thickness of the ramifications branching from the right anterior segmental portal vein (PA) were evaluated for variations.
  
  
  
  In all subjects, the diverging point of the PA-Dwas constantly distal to that of the PLL. The portal vein configuration was I- and Z-shaped in nine and five subjects, respectively. The RUP was tilted to the right in all subjects. In Z-shaped subjects, the portal trunk between the branching point of the right posterior segmental portal vein and that of the PLLwas tilted to the left in one subject and was almost parallel to the vertical plane in four subjects. Multiple ramifications were radially distributed from the PAin eight subjects, whereas one predominant PA-Dbranched from the PAin six subjects.
  
  
  
  Based on the diverging points of the PA-Dand PLL, we proposed a three-step method for the detection and diagnosis of RSRL.
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan. rickdom@kuhp.kyoto-u.ac.jp.
authors.forename: Rikiya
authors.initials: R
authors.lastname: Yamashita
authors.affiliation: Department of Diagnostic Imaging and Interventional Radiology, Kyoto-Katsura Hospital, 17 Yamada-Hirao, Nishikyo, Kyoto, 615-8256, Japan.
authors.forename: Toshihide
authors.initials: T
authors.lastname: Yamaoka
authors.affiliation: Department of Surgery, Kyoto-Katsura Hospital, 17 Yamada-Hirao, Nishikyo, Kyoto, 615-8256, Japan.
authors.forename: Ryuta
authors.initials: R
authors.lastname: Nishitai
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan.
authors.forename: Hiroyoshi
authors.initials: H
authors.lastname: Isoda
authors.affiliation: Division of Hepato-Biliary-Pancreatic and Transplant Surgery, Department of Surgery, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan.
authors.forename: Kojiro
authors.initials: K
authors.lastname: Taura
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan.
authors.forename: Shigeki
authors.initials: S
authors.lastname: Arizono
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Furuta
authors.affiliation: Department of Diagnostic Imaging, Osaka Red Cross Hospital, 5-30 Fudegasaki-cho, Tennoji-ku, Osaka, 543-8555, Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Ohno
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan.
authors.forename: Ayako
authors.initials: A
authors.lastname: Ono
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan.
authors.forename: Kaori
authors.initials: K
authors.lastname: Togashi
mesh_terms: D000328:Adult; D000368:Aged; D003287:Contrast Media; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011169:Portal Vein / Q000033:anatomy & histology*; D012189:Retrospective Studies; D000069592:Round Ligament of Liver / Q000002:abnormalities*; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media
keywords: Computed tomography; Portal vein anatomy; Portal vein branching order; Right-sided ligamentum teres; Right-sided round ligament