title: A comparison of cerebral hemodynamic parameters between transient monocular blindness patients, transient ischemic attack patients and control subjects.
abstract: OBJECTIVE
  To assess whether patients with transient monocular blindness (TMB) and patients with hemispheric transient ischemic attacks (hTIA) differ from each other with respect to cerebral hemodynamic parameters.
  
  
  METHODS
  Seventeen TMB patients and 23 hTIA patients with a moderate to severe stenosis or an occlusion of the internal carotid artery (ICA) underwent magnetic resonance (MR) angiography, (1)H MR spectroscopy and transcranial Doppler sonography. Thirty-one control subjects were investigated to obtain reference values for the MR investigations. Quantitative flow was measured in the ICAs, the basilar artery and the middle cerebral arteries (MCA). Metabolic changes in the MCA territory were studied by assessing N-acetyl-aspartate (NAA)/choline ratios and prevalences of lactate. The prevalence of collateral flow was assessed in the circle of Willis and the ophthalmic arteries. The vasomotor reactivity was studied by measuring the CO(2) reactivity of the MCA territories.
  
  
  RESULTS
  Quantitative flow in the cerebropetal arteries and the MCAs did not differ between TMB patients and hTIA patients. Also patterns of collateral flow, prevalence of lactate and CO(2) reactivity were similar. The mean ipsilateral NAA/choline ratio was lower in hTIA patients compared with TMB patients (p < 0.01), and was predominantly correlated with symptomatology (p < 0.01), i.e. whether patients had TMB or hTIA, and not with ipsilateral MCA flow (p = 0.2) or ipsilateral CO(2) reactivity (p = 0.7).
  
  
  CONCLUSIONS
  The results of this study indicate that there are no cerebral hemodynamic differences between TMB patients and hTIA patients. It is therefore unlikely that hemodynamic factors account for differences in clinical characteristics between the two patient groups.
authors.affiliation: Department of Radiology, University Medical Center Utrecht, The Netherlands. D.Rutgers@azu.nl
authors.forename: D R
authors.initials: DR
authors.lastname: Rutgers
authors.forename: R C
authors.initials: RC
authors.lastname: Donders
authors.forename: E M
authors.initials: EM
authors.lastname: Vriens
authors.forename: L J
authors.initials: LJ
authors.lastname: Kappelle
authors.forename: J
authors.initials: J
authors.lastname: van der Grond
mesh_terms: D020757:Amaurosis Fugax / Q000000981:diagnostic imaging* / Q000503:physiopathology; D001488:Basilar Artery / Q000502:physiology; D001921:Brain / Q000098:blood supply / Q000378:metabolism; D002560:Cerebrovascular Circulation / Q000502:physiology*; D002941:Circle of Willis / Q000502:physiology; D003097:Collateral Circulation / Q000502:physiology; D004734:Energy Metabolism / Q000502:physiology; D005260:Female; D006801:Humans; D020244:Infarction, Middle Cerebral Artery / Q000000981:diagnostic imaging / Q000503:physiopathology; D002546:Ischemic Attack, Transient / Q000000981:diagnostic imaging* / Q000503:physiopathology; D019344:Lactic Acid / Q000378:metabolism; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D017585:Ultrasonography, Doppler, Transcranial
chemical_list: D019344:Lactic Acid