title: Analysis of the venous channel within the clivus using multidetector computed tomography digital subtraction venography.
abstract: OBJECTIVE
  Although neuroradiologists and skull base neurosurgeons are aware of the existence of veins within the clivus, such vessels have seldom been described in the literature. The aim of the present study is to elucidate the detailed venous structure of the clivus.
  
  
  METHODS
  Computed tomography digital subtraction venography (CT-DSV) images of 50 unruptured aneurysm cases were examined retrospectively.
  
  
  RESULTS
  Eighteen emissary veins were identified in 14 (28.0%) cases. A half of the emissary veins connected the inferior petrosal sinus with the inferior petro-occipital vein (IPOV) in the middle clivus. The clival diploic vein (CDV) was identified in 14.0% of cases, 42.9% of which had the clivus of the presellar type. The CDV was connected to the posterior intercavernous sinus or the rostral end of the basilar plexus superiorly, and was connected to the IPOV, anterior condylar vein, marginal sinus, or the anterior condylar confluence.
  
  
  CONCLUSIONS
  The CDV provides collateral channels between the cavernous sinus and the internal jugular vein and the inferior petrosal sinus and the IPOV. Understanding of the emissary veins in the clivus and the CDV is valuable for skull base surgery, especially for endonasal endoscopic skull base procedures.
authors.affiliation: Department of Neurosurgery, Keio University School of Medicine, 35 Shinanomachi Shinjuku City, Tokyo, 160-0016, Japan. katsu512@yahoo.co.jp.
authors.forename: Katsuhiro
authors.identifier: http://orcid.org/0000-0002-3158-0189
authors.initials: K
authors.lastname: Mizutani
authors.affiliation: Department of Neurosurgery, Keio University School of Medicine, 35 Shinanomachi Shinjuku City, Tokyo, 160-0016, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Toda
authors.affiliation: Department of Radiology, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Kurasawa
authors.affiliation: Department of Neurosurgery, Keio University School of Medicine, 35 Shinanomachi Shinjuku City, Tokyo, 160-0016, Japan.
authors.forename: Takenori
authors.initials: T
authors.lastname: Akiyama
authors.affiliation: Department of Radiology, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Fujiwara
authors.affiliation: Department of Radiology, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Jinzaki
authors.affiliation: Department of Neurosurgery, Keio University School of Medicine, 35 Shinanomachi Shinjuku City, Tokyo, 160-0016, Japan.
authors.forename: Kazunari
authors.initials: K
authors.lastname: Yoshida
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015901:Angiography, Digital Subtraction; D002550:Cerebral Veins / Q000000981:diagnostic imaging*; D003287:Contrast Media; D003388:Cranial Fossa, Posterior / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography / Q000379:methods*; D012189:Retrospective Studies
chemical_list: D003287:Contrast Media
keywords: Clival diploic vein; Clivus; Emissary vein; Endonasal endoscopic skull base surgery