title: Arterial spin labeling and altered cerebral blood flow patterns in the minimally conscious state.
abstract: OBJECTIVE
  To use arterial spin labeling (ASL) to compare cerebral blood flow (CBF) patterns in minimally conscious state (MCS) patients with those in normal controls in an observational study design.
  
  
  METHODS
  Subjects meeting MCS criteria and normal controls were identified. A pseudocontinuous ASL sequence was performed with subjects and controls in the resting awake state. Multiple CBF values for 10 predetermined regions of interest were sampled and average CBF was calculated and compared between controls and subjects.
  
  
  RESULTS
  Ten normal controls were identified, with ages ranging from 26 to 54 years. Four subjects met the MCS criteria and received an ASL study, with one patient receiving a second study at a later date. Subjects ranged in age from 19 to 58 years and had traumatic brain injury, stroke, or hypoxic-ischemic encephalopathy. Regional CBF for controls ranged from 21.6 to 57.2 mL/100 g/min, with a pattern of relatively increased blood flow posteriorly including the posterior cingulate, parietal, and occipital cortices. CBF patterns for MCS subjects showed greater variability (from 7.7 to 33.1 mL/100 g/min), demonstrating globally decreased CBF in gray matter compared with that in normal controls, especially in the medial prefrontal and midfrontal regions. In the one subject studied longitudinally, global CBF values increased over time, which correlated with clinical improvement.
  
  
  CONCLUSIONS
  We identified globally decreased CBF and a selective reduction of CBF within the medial prefrontal and midfrontal cortical regions as well as gray matter in MCS patients. ASL may serve as an adjunctive method to assess functional reserve in patients recovering from severe brain injuries.
authors.affiliation: Beth Israel Deaconess-Harvard University, 330 Brookline Avenue, Boston, MA 02215, USA. aaliu@bidmc.harvard.edu
authors.forename: A A
authors.initials: AA
authors.lastname: Liu
authors.forename: H U
authors.initials: HU
authors.lastname: Voss
authors.forename: J P
authors.initials: JP
authors.lastname: Dyke
authors.forename: L A
authors.initials: LA
authors.lastname: Heier
authors.forename: N D
authors.initials: ND
authors.lastname: Schiff
mesh_terms: D000328:Adult; D001158:Arteries / Q000503:physiopathology*; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000098:blood supply*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D019370:Observation; D010100:Oxygen / Q000097:blood; D018458:Persistent Vegetative State / Q000378:metabolism / Q000503:physiopathology*; D013113:Spin Labels; D055815:Young Adult
chemical_list: D013113:Spin Labels; D010100:Oxygen