title: Intracranial MR venography using low-field magnet: normal anatomy and variations in Nepalese population.
abstract: BACKGROUND
  Magnetic resonance (MR) venography is considered a reliable imaging modality for the evaluation of intracranial venous system. The purpose of this study was to evaluate the normal venous anatomy and its variations in Nepalese population using low field MR technique.
  
  
  METHODS
  One hundred patients with normal MR imaging of brain underwent MR venographic study. MR venograms were performed in 0.35 T MR scanner using a contiguous 2D time-of-flight MR angiographic technique.
  
  
  RESULTS
  The flow gaps in the transverse sinus were seen in 47% of population, of which 91% occurred in the non-dominant side. Right transverse sinus was dominant in 73% population. Flow gap was observed in bilateral transverse sinus in one case, while it was seen in the dominant right transverse sinus in 6.3% population. Inferior sagittal sinus was observed in 11% cases. Internal cerebral vein was seen in 60 cases. Occipital sinus was observed in 4% of the cases. The basal vein of Rosenthal was observed in 34% of the cases, whereas vein of Labbe seen in 8% cases. Unilateralflow gap in the sigmoid sinus was seen in 5 cases.
  
  
  CONCLUSIONS
  MR angiography done at low field MR unit is a reliable tool in cerebral venous sinus assessment, particularly major dural sinuses. The flow gaps in transverse sinus are frequently encountered anatomic variation. Visualization of small veins like inferior sagittal sinus, basal vein of Rosenthal, vein of Labbe, internal cerebral vein was inferior in our study compared to other studies done in high field MR unit.
authors.affiliation: Department of Radiodiagnosis, B & B Hospital, Gwarku, Lalitpur, Nepal.
authors.forename: U K
authors.initials: UK
authors.lastname: Sharma
authors.forename: K
authors.initials: K
authors.lastname: Sharma
mesh_terms: D002533:Cerebral Angiography / Q000379:methods*; D003392:Cranial Sinuses / Q000033:anatomy & histology*; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000379:methods*; D009390:Nepal; D054063:Superior Sagittal Sinus / Q000033:anatomy & histology; D054064:Transverse Sinuses / Q000033:anatomy & histology