title: Dynamic physostigmine effects on hippocampus perfusion.
abstract: OBJECTIVE
  To characterize the dynamic response of hippocampus blood flow to physostigmine infusion and to determine an infusion duration sufficiently long for robust detection of effects with arterial spin labeling (ASL) and sufficiently short to avoid peripheral side effects of physostigmine.
  
  
  METHODS
  Two female (49 ± 15 years) and nine male (53 ± 13 years) subjects were studied to determine the time course of the physostigmine effect on hippocampus blood flow with ASL perfusion imaging during 20 minutes of baseline, 30 minutes of physostigmine infusion at 1.0 mg/hr, and 70 minutes of recovery.
  
  
  RESULTS
  Hippocampus perfusion decreased steadily over the course of the infusion, with the reduction in flow becoming significant after 20 minutes of infusion, reaching lowest levels near the end of infusion, and remaining significantly low and stable in the 70-minute recovery period. Percentage changes of hippocampus perfusion were -13.3%, -13.4%, and -13.4% for left, right, and bilateral hippocampus, respectively, at the end of infusion.
  
  
  CONCLUSIONS
  At a dose rate of 1.0 mg/hr it is feasible to use an infusion time as short as 20 minutes, performing perfusion imaging up to an hour after physostigmine infusion is discontinued, to minimize chances for adverse side effects.
authors.affiliation: Radiology, UT Southwestern Medical Center, Dallas, Texas 75390-8896, USA.
authors.forename: Xiufeng
authors.initials: X
authors.lastname: Li
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Spence
authors.forename: David M
authors.initials: DM
authors.lastname: Buhner
authors.forename: Robert W
authors.initials: RW
authors.lastname: Haley
authors.forename: Richard W
authors.initials: RW
authors.lastname: Briggs
mesh_terms: D000328:Adult; D002800:Cholinesterase Inhibitors / Q000008:administration & dosage / Q000493:pharmacokinetics*; D005260:Female; D006624:Hippocampus / Q000098:blood supply*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007262:Infusions, Intravenous; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010830:Physostigmine / Q000008:administration & dosage / Q000493:pharmacokinetics*; D013113:Spin Labels; D013997:Time Factors
chemical_list: D002800:Cholinesterase Inhibitors; D013113:Spin Labels; D010830:Physostigmine