title: The anterior medullary-anterior pontomesencephalic venous system and its bridging veins communicating to the dural sinuses: normal anatomy and drainage routes from dural arteriovenous fistulas.
abstract: BACKGROUND
  We evaluated the normal venous anatomy of the anterior medullary/anterior pontomesencephalic venous (AMV/APMV) system and bridging veins connected to the dural sinuses using magnetic resonance (MR) imaging and demonstrated cases of dural arteriovenous fistulas (DAVFs) with bridging venous drainage.
  
  
  METHODS
  MR images obtained using a 3D gradient echo sequence in 70 patients without lesions affecting the deep or posterior venous channels were reviewed to evaluate the normal anatomy of the AMV/APMV system and bridging veins. MR images and digital subtraction angiography in 80 cases with intracranial or craniocervical junction DAVFs were reviewed to evaluate the bridging venous drainage from DAVFs.
  
  
  RESULTS
  MR images clearly revealed AMV/APMV in 35 cases. Fifteen cases showed a direct connection between AMV and APMV, while 15 cases showed an indirect communication via the transverse pontine vein or the bridging vein. In the five remaining cases, the AMV and APMV end separately to the bridging vein or the transverse pontine vein. Bridging veins were identified in 34 cases, connecting to the cavernous sinus in 33, to the suboccipital cavernous sinus in 11, and the inferior petrosal sinus in five cases. In 80 DAVF cases, seven of 40 cavernous sinus DAVFs, two craniocervical junction DAVFs, and one inferior petrosal sinus DAVF drained via bridging veins to the brain stem.
  
  
  CONCLUSIONS
  The AMV/APMV and bridging veins showed various anatomies and frequently showed a connection to the cavernous sinus. Knowledge of the venous anatomy is helpful for the diagnosis and intravascular treatment of DAVFs.
authors.affiliation: Department of Radiology, Oita University Faculty of Medicine, Hasama, Yufu City, Oita, Japan. hkiyosue@med.oita-u.ac.jp
authors.forename: Hiro
authors.initials: H
authors.lastname: Kiyosue
authors.forename: Shuichi
authors.initials: S
authors.lastname: Tanoue
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Sagara
authors.forename: Yuzo
authors.initials: Y
authors.lastname: Hori
authors.forename: Mika
authors.initials: M
authors.lastname: Okahara
authors.forename: Junji
authors.initials: J
authors.lastname: Kashiwagi
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Nagatomi
authors.forename: Hiromu
authors.initials: H
authors.lastname: Mori
mesh_terms: D000328:Adult; D000368:Aged; D001933:Brain Stem / Q000098:blood supply*; D020785:Central Nervous System Vascular Malformations / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology*; D002550:Cerebral Veins / Q000473:pathology / Q000503:physiopathology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D015331:Cohort Studies; D003392:Cranial Sinuses / Q000473:pathology / Q000503:physiopathology; D017352:Echo-Planar Imaging; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D011859:Radiography; D012189:Retrospective Studies