title: Imaging cerebral blood flow in the cognitively normal aging brain with arterial spin labeling: implications for imaging of neurodegenerative disease.
abstract: BACKGROUND
  Arterial spin labeling (ASL) is a safe, noninvasive imaging method for evaluating cerebral blood flow (rCBF). The purpose of this article is to present ASL imaging features of 38 elderly cognitively normals (CN) with their rCBF values and an averaged profile of targeted anatomic regions rCBF values.
  
  
  METHODS
  Thirty-eight CN underwent MR imaging especially ASL with voxel morphometric techniques fusing the MR anatomical and ASL images to a standard reference brain (colin27). The ASL images were fused to echo planar images, which were then coregistered to high-resolution anatomical SPGR images. rCBF was calculated per region of interest using a modified continuous arterial spin labeling (CASL) convolutional method. Anatomical regions were selected and identified by the Talairach atlas in SPM2.
  
  
  RESULTS
  We identified areas of decreased and increased perfusion (compared to the averaged rCBF of all 38 CN) corresponding to decreased and increased quantified rCBF. The most common sites for decreased perfusion were precuneus (53%), superior temporal (48%), and orbitofrontal (37%), and for increased perfusion the caudate (39%), posterior cingulate (34%), anterior cingulate (32%), and amygdala (32%).
  
  
  CONCLUSIONS
  There are regional variations in rCBF both increased and decreased with the posterior cingulate and precuneus cortex showing the highest averaged values and signal intensity (bright spots). These variations represent the normal profile of a CN elderly brain, with higher perfusion in areas associated with cognition, memory, and behavior. It is necessary to understand these normal variations in order to determine if there are perfusion changes in ASL detected in neurodegenerative disorders such as Alzheimer's disease.
authors.affiliation: Department of Radiology, Neuroradiology Division, University of Pittsburgh Medical Center, Pittsburgh, PA 15213-2582, USA. leec@upmc.edu
authors.forename: Charles
authors.initials: C
authors.lastname: Lee
authors.forename: Oscar L
authors.initials: OL
authors.lastname: Lopez
authors.forename: James T
authors.initials: JT
authors.lastname: Becker
authors.forename: Cyrus
authors.initials: C
authors.lastname: Raji
authors.forename: Weiying
authors.initials: W
authors.lastname: Dai
authors.forename: Lewis H
authors.initials: LH
authors.lastname: Kuller
authors.forename: H Michael
authors.initials: HM
authors.lastname: Gach
mesh_terms: D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D001921:Brain / Q000098:blood supply* / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D002560:Cerebrovascular Circulation; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D019636:Neurodegenerative Diseases / Q000503:physiopathology; D012815:Signal Processing, Computer-Assisted; D013113:Spin Labels
chemical_list: D013113:Spin Labels