title: Right double inferior vena cava: Report of 5 cases and literature review.
abstract: OBJECTIVE
  To describe the computed tomography appearance, embryology, and clinical implications of right double inferior vena cava (IVC).
  
  
  METHODS
  Computed tomography imaging findings were retrospectively reviewed in our 5 patients and in 2 cases reported in the literature with right double IVC. The relationship of the 2 postrenal IVCs, their diameter, level of confluence of the 2 IVCs, course of the left common iliac vein, draining site of the right gonadal vein, and the presence of retrocaval ureter were evaluated.
  
  
  RESULTS
  In all cases, the relationship of 2 IVCs was ventral-dorsal, and the left common iliac vein passed ventral to the aortic bifurcation or the right common iliac artery. The relationship of the diameters and level of confluence of the 2 IVCs were variable. The right gonadal vein drained into the ventral vessel in 4 cases and into the IVC between the renal venous confluence and the confluence of the 2 vessels in 1 case. In all cases, the retrocaval ureter was not identified.
  
  
  CONCLUSIONS
  Characteristic computed tomography findings of right double IVC were a ventral-dorsal relationship between the 2 vessels and the unusual course of the left common iliac vein. Embryologically, the ventral vessel originates from the right subcardinal vein, whereas the dorsal vessel originates from the right supracardinal vein. Although this anomaly is extremely rare, radiologists should recognize it.
authors.affiliation: Department of Radiology, Yokohama City University Hospital, Yokohama, Kanagawa, Japan. tn1011@med.yokohama-cu.ac.jp
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Nagashima
authors.forename: Jin
authors.initials: J
authors.lastname: Lee
authors.forename: Kazuo
authors.initials: K
authors.lastname: Andoh
authors.forename: Takashi
authors.initials: T
authors.lastname: Itoh
authors.forename: Kazunori
authors.initials: K
authors.lastname: Tanohata
authors.forename: Mito
authors.initials: M
authors.lastname: Arai
authors.forename: Tomio
authors.initials: T
authors.lastname: Inoue
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D014682:Vena Cava, Inferior / Q000002:abnormalities* / Q000000981:diagnostic imaging