title: Detection of intracranial venous reflux in patients of transient global amnesia.
abstract: BACKGROUND
  The mechanism of transient global amnesia (TGA) is not clear. Attempting to support the hypothesis that retrograde venous hypertension causing cerebral venous ischemia plays a role in the pathogenesis of TGA, the authors used cranial three-dimensional time-of-flight (TOF) MR angiography (MRA) to detect a possible intracranial retrograde venous flow in TGA patients.
  
  
  METHODS
  The frequency of abnormal venous signals on cranial three-dimensional TOF MRA was compared in 10 TGA patients with the signals in 50 age- and gender-matched normal individuals. In TGA patients with abnormal venous signals, other examinations (cerebral digital subtraction angiography, upper extremity digital subtraction venography [DSV], and thoracic inlet MRI) were performed to elucidate the etiology of these abnormal intracranial venous flow patterns.
  
  
  RESULTS
  Abnormal venous signals on three-dimensional TOF MRA were found in five (50%) of the TGA patients and none of the control subjects (p < 0.001). Compression leading to occlusion of the left brachiocephalic vein by the sternum and aorta during regular breathing, as depicted by upper extremity DSV and thoracic inlet MRI, occurred consistently among these five TGA patients with abnormal venous signals.
  
  
  CONCLUSIONS
  Retrograde intracranial venous flow caused by left brachiocephalic vein occlusion was found only in patients with transient global amnesia (TGA). This result suggests that TGA patients may have an underlying impairment of cerebral venous outflow that increases their vulnerability to TGA attack.
authors.affiliation: Section of Neurovascular Diseases, Neurological Institute, Department of Radiology, Veterans General Hospital-Taipei, National Yang-Ming University, Taipei, Taiwan.
authors.forename: C-P
authors.initials: CP
authors.lastname: Chung
authors.forename: H-Y
authors.initials: HY
authors.lastname: Hsu
authors.forename: A-C
authors.initials: AC
authors.lastname: Chao
authors.forename: F-C
authors.initials: FC
authors.lastname: Chang
authors.forename: W-Y
authors.initials: WY
authors.lastname: Sheng
authors.forename: H-H
authors.initials: HH
authors.lastname: Hu
mesh_terms: D000368:Aged; D020236:Amnesia, Transient Global / Q000175:diagnosis* / Q000209:etiology*; D002550:Cerebral Veins / Q000473:pathology*; D002561:Cerebrovascular Disorders / Q000150:complications* / Q000175:diagnosis*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D013223:Statistics as Topic