title: Flow velocity of the superior sagittal sinus is reduced in patients with idiopathic normal pressure hydrocephalus.
abstract: BACKGROUND
  The pathogenesis and diagnostic methods for idiopathic normal pressure hydrocephalus (iNPH) have been active areas of research in recent years. This study was performed to determine whether there is a venous return abnormality in the intracranial circulation of patients with iNPH.
  
  
  METHODS
  The subjects were 20 patients with iNPH (Group N) and 24 normal controls (Group C). MR venography (MRV) was performed at the superior sagittal sinus 2 cm above the confluence of the sinuses, and the flow velocities were compared between Groups N and C.
  
  
  RESULTS
  During normal breathing, the maximum velocities were significantly lower in Group N (18.8 cm/second) than in Group C (22.9 cm/second; (P < .01). During the Valsalva maneuver, compared to normal breathing, the velocity decreased in both groups, but both the maximum (Max V) and minimum (Min V) velocities were significantly lower in Group N than in Group C (P < .01).
  
  
  CONCLUSIONS
  The flow velocity at the superior sagittal sinus was lower and the flow velocity during the Valsalva maneuver decreased more in patients with iNPH than in controls. The results may reflect the presence of abnormal intracranial venous flow in iNPH.
authors.affiliation: Department of Neurology, Kyoto Prefectural University of Medicine, Kyoto, Japan. nkuriyam@koto.kpu-m.ac.jp
authors.forename: Nagato
authors.initials: N
authors.lastname: Kuriyama
authors.forename: Takahiko
authors.initials: T
authors.lastname: Tokuda
authors.forename: Kei
authors.initials: K
authors.lastname: Yamada
authors.forename: Kentaro
authors.initials: K
authors.lastname: Akazawa
authors.forename: Makoto
authors.initials: M
authors.lastname: Hosoda
authors.forename: Koji
authors.initials: K
authors.lastname: Sakai
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Watanabe
authors.forename: Masanori
authors.initials: M
authors.lastname: Nakagawa
mesh_terms: D000368:Aged; D001783:Blood Flow Velocity / Q000502:physiology*; D005260:Female; D006801:Humans; D006850:Hydrocephalus, Normal Pressure / Q000000981:diagnostic imaging / Q000503:physiopathology*; D008297:Male; D010690:Phlebography; D054063:Superior Sagittal Sinus / Q000000981:diagnostic imaging / Q000503:physiopathology*; D014463:Ultrasonography; D014636:Valsalva Maneuver