title: Arterial spin-labeling magnetic resonance imaging: the timing of regional maximal perfusion-related signal intensity revealed by a multiphase technique.
abstract: OBJECTIVE
  We investigated the time interval from labeling to peak (TLP) of perfusion-signal intensity (SIs) in normal brain using a multiphase arterial spin-labeling (ASL) magnetic resonance imaging (MRI) technique as a fundamental study to assess the temporal characteristics of perfusion SIs.
  
  
  METHODS
  Twenty temporal phases of a pulsed ASL-MRI [QUASAR, quantitative signal targeting by alternating radiofrequency pulses (STAR) labeling of arterial regions] in single-slice imaging were performed in 9 volunteers. Perfusion SIs were measured and TLPs were calculated in 14 regions of interest (ROIs), 7 in each hemisphere: thalamus, lentiform nucleus, medial frontal cortex in the anterior cerebral artery (ACA) territory, temporal cortex in the middle cerebral artery (MCA) territory, medial occipital cortex in the posterior cerebral artery (PCA) territory, anterior watershed region (AWR) and posterior watershed region (PWR).
  
  
  RESULTS
  Mean TLP varied with ROI (region and mean ± standard deviation in seconds): thalamus, 1.60 ± 0.11; lentiform nucleus, 1.52 ± 0.11; ACA territory, 1.53 ± 0.16; MCA territory, 1.59 ± 0.18; PCA territory, 1.68 ± 0.20; AWR, 1.79 ± 0.14; PWR, 2.00 ± 0.20. TLP in the PWR was significantly longer than those in all other regions except the AWR, and TLP in the AWR was significantly longer than those in the lentiform nucleus and the ACA territory.
  
  
  CONCLUSIONS
  Our results revealed regional differences in the temporal characteristics of perfusion SIs on ASL-MRI.
authors.affiliation: Department of Radiology, Faculty of Medicine, Saga University, 5-1-1 Nabeshima, Saga, Saga, 849-8501, Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Noguchi
authors.forename: Takashi
authors.initials: T
authors.lastname: Yoshiura
authors.forename: Akio
authors.initials: A
authors.lastname: Hiwatashi
authors.forename: Osamu
authors.initials: O
authors.lastname: Togao
authors.forename: Koji
authors.initials: K
authors.lastname: Yamashita
authors.forename: Eiki
authors.initials: E
authors.lastname: Nagao
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Honda
mesh_terms: D000328:Adult; D002560:Cerebrovascular Circulation; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D013113:Spin Labels; D055815:Young Adult
chemical_list: D013113:Spin Labels