title: Pulsed arterial spin labeling parameter optimization for an elderly population.
abstract: OBJECTIVE
  To optimize pulsed arterial spin labeling (PASL) parameters for the elderly to take into account possible perfusion changes that occur in the brain with age.
  
  
  METHODS
  Healthy young (N = 14, age range = 21-27 years) and elderly (N = 12, age range = 61-67 years) subjects were scanned using Q2TIPS (QUIPSS II with thin-slice TI, periodic saturation) with varying inversion times (TI(2)) at 1.5T. The difference signal (DeltaM), transit time (deltat), and cerebral blood flow (CBF) were calculated in segmented gray matter (GM).
  
  
  RESULTS
  The young displayed more perfusion-weighted signal difference than the elderly at all TI(2)'s. The peak DeltaM occurred at TI(2) approximately 1300 msec and 1500 msec in the young and elderly groups, respectively. Qualitatively, intravascular signal was minimal in the younger group by TI(2) = 1500 msec, whereas a longer TI(2) of 1800 msec was needed to minimize this signal in the elderly. The transit time was approximately 100 msec longer in the elderly, and CBF was in the range of literature values.
  
  
  CONCLUSIONS
  For acquiring perfusion-weighted images with minimal intravascular signal and adequate tissue signal for PASL studies of cerebral perfusion in the elderly, a longer inversion time is advantageous.
authors.affiliation: Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada T6G 2V2.
authors.forename: Alison M
authors.initials: AM
authors.lastname: Campbell
authors.forename: Christian
authors.initials: C
authors.lastname: Beaulieu
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D002560:Cerebrovascular Circulation; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D013113:Spin Labels
chemical_list: D013113:Spin Labels