title: Evaluation of cerebral blood flow using multi-phase pseudo continuous arterial spin labeling at 3-tesla.
abstract: OBJECTIVE
  Arterial spin labeling (ASL) methods have been widely used for evaluation of cerebral blood flow (CBF) by magnetic resonance imaging. However, ASL methods require setting of the post labeling delay (PLD) time for obtaining images. As the hemodynamic status cannot be estimated in each patient, the resultant quantitative values of blood flow may not be accurate. The multi-phase pseudo continuous arterial spin labeling (pCASL) method can be used to obtain images at various time-points. The purpose of this study was to create the transit-time maps for correcting the delayed blood flow and evaluate CBF using the transit-time maps obtained by the multi-phase pCASL method.
  
  
  METHODS
  Twelve patients who underwent both 3.0-tesla magnetic resonance imaging (MRI) and single photon emission computed tomography with iodine-123-N-isopropyl-p-iodoamphetamine (123I-IMP) were investigated. This study was approved by the institutional review board of our institution. MRI acquisitions included PLD time-fixed (1525ms) and multi-phase pCASL sequences. The transit-time maps were calculated from multi-phase pCASL images by software. The transit-time maps were applied to PLD-fixed pCASL images pixel by pixel, for calculating the CBF value corrected for peak blood transit time. Regions of interest were drawn on the brain. IMP-CBF, ASL-CBF (default and corrected) and transit time were measured for each segment.
  
  
  RESULTS
  Twelve patients and 264 segments were investigated. The mean IMP-CBF, ASL-CBF (default, corrected) and transit time were 28.4, 23.0, 29.6, [ml/min/100g] and 1977.5 [ms], respectively. There were no significant differences between IMP-CBF and ASL-CBF (corrected).
  
  
  CONCLUSIONS
  CBF values can be corrected by using the transit-time maps obtained using the multi-phase pCASL method.
authors.affiliation: Department of Radiological Technology, Hokkaido University Hospital, North-14, West-5, Kita-ku, Sapporo, Hokkaido, Japan 060-8648. Electronic address: sugimori@huhp.hokudai.ac.jp.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Sugimori
authors.affiliation: Department of Diagnostic and Interventional Radiology, Hokkaido University Hospital, North-15, West-7, Kita-ku, Sapporo, Hokkaido, Japan 060-8638. Electronic address: fujima@med.hokudai.ac.jp.
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Fujima
authors.affiliation: Philips Electronics Japan, 2-13-37 Kohnan, Minato-Ku, Tokyo, Japan, 108-8507. Electronic address: yuriko.suzuki@philips.com.
authors.forename: Yuriko
authors.initials: Y
authors.lastname: Suzuki
authors.affiliation: Department of Radiological Technology, Hokkaido University Hospital, North-14, West-5, Kita-ku, Sapporo, Hokkaido, Japan 060-8648. Electronic address: hhummer@huhp.hokudai.ac.jp.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Hamaguchi
authors.affiliation: Graduate School of Health Sciences, Hokkaido University, North-12, West-5, Kita-ku, Sapporo, Hokkaido, Japan 060-0812. Electronic address: moto@hs.hokudai.ac.jp.
authors.forename: Motomichi
authors.initials: M
authors.lastname: Sakata
authors.affiliation: Department of Diagnostic and Interventional Radiology, Hokkaido University Hospital, North-15, West-7, Kita-ku, Sapporo, Hokkaido, Japan 060-8638. Electronic address: kkudo@huhp.hokudai.ac.jp.
authors.forename: Kohsuke
authors.initials: K
authors.lastname: Kudo
mesh_terms: D000368:Aged; D001921:Brain / Q000098:blood supply*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D015203:Reproducibility of Results; D013113:Spin Labels
chemical_list: D013113:Spin Labels
keywords: Arterial spin labeling; Arterial transit time; Cerebral blood flow; Multi-phase pseudo continuous arterial spin labeling