title: Mild cognitive impairment and alzheimer disease: patterns of altered cerebral blood flow at MR imaging.
abstract: OBJECTIVE
  To examine regional cerebral blood flow (rCBF) in incident mild cognitive impairment (MCI) and Alzheimer disease (AD) by using continuous arterial spin-labeling (CASL) magnetic resonance (MR) imaging.
  
  
  METHODS
  This study was approved by the local institutional review board and was compliant with HIPAA regulations. Informed consent was obtained. rCBF was measured in 38 control subjects, 29 MCI patients, and 37 AD patients who were participating in a longitudinal epidemiologic study. Multisection CASL MR imaging with alternating single and double adiabatic inversion pulses and ramp-sampled echo-planar imaging were performed to acquire 19 contiguous axial sections. Voxel-level rCBF was compared among groups by using an analysis of variance design; clusters of voxels with significant group differences were identified. Multiple regression models controlled for age, sex, and presence of hypertension and related the mean rCBF in those clusters to the presence of MCI and AD.
  
  
  RESULTS
  MCI and AD patients had decreased rCBF in the posterior cingulate gyrus (P = .01) with extension to the medial precuneus compared with that in control subjects. MCI patients had increased rCBF in the left hippocampus (P < .001), right amygdala (P = .007), and rostral head of the right caudate nucleus and ventral putamen and globus pallidus (P = .003) compared with that in control subjects. AD patients had decreased rCBF relative to that in control subjects and MCI patients in the left inferior parietal (P = .005), left lateral frontal (P < .001), left superior temporal (P = .001), and left orbitofrontal (P = .003) cortices. AD patients had increased rCBF in the right anterior cingulate gyrus (P = .02) compared with that in control subjects.
  
  
  CONCLUSIONS
  The transition from normal cognition to AD is associated with dynamic pathologic processes in the brain, and this is reflected by both decreases and increases in rCBF. Increases in rCBF suggest a cellular and vascular compensatory process associated with incipient AD.
  
  
  BACKGROUND
  http://radiology.rsnajnls.org/cgi/content/full/2503080751/DC1.
authors.affiliation: Department of Radiology, Harvard Medical School, Boston, Mass, USA.
authors.forename: Weiying
authors.initials: W
authors.lastname: Dai
authors.forename: Oscar L
authors.initials: OL
authors.lastname: Lopez
authors.forename: Owen T
authors.initials: OT
authors.lastname: Carmichael
authors.forename: James T
authors.initials: JT
authors.lastname: Becker
authors.forename: Lewis H
authors.initials: LH
authors.lastname: Kuller
authors.forename: H Michael
authors.initials: HM
authors.lastname: Gach
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000150:complications* / Q000175:diagnosis*; D001921:Brain / Q000098:blood supply*; D002560:Cerebrovascular Circulation; D003072:Cognition Disorders / Q000150:complications* / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male