title: Forced convective head cooling device reduces human cross-sectional brain temperature measured by magnetic resonance: a non-randomized healthy volunteer pilot study.
abstract: BACKGROUND
  This pilot study in five healthy adult humans forms the pre-clinical assessment of the effect of a forced convective head cooling device on intracranial temperature, measured non-invasively by magnetic resonance spectroscopy (MRS).
  
  
  METHODS
  After a 10 min baseline with no cooling, subjects received 30 min of head cooling followed by 30 min of head and neck cooling via a hood and neck collar delivering 14.5 degrees C air at 42.5 litre s(-1). Over baseline and at the end of both cooling periods, MRS was performed, using chemical shift imaging, to measure brain temperature simultaneously across a single slice of brain at the level of the basal ganglia. Oesophageal temperature was measured continuously using a fluoroptic thermometer.
  
  
  RESULTS
  MRS brain temperature was calculated for baseline and the last 10 min of each cooling period. The net brain temperature reduction with head cooling was 0.45 degrees C (SD 0.23 degrees C, P=0.01, 95% CI 0.17-0.74 degrees C) and with head and neck cooling was 0.37 degrees C (SD 0.30 degrees C, P=0.049, 95% CI 0.00-0.74 degrees C). The equivalent net reductions in oesophageal temperature were 0.16 degrees C (SD 0.04 degrees C) and 0.36 degrees C (SD 0.12 degrees C). Baseline-corrected brain temperature gradients from outer through intermediate to core voxels were not significant for either head cooling (P=0.43) or head and neck cooling (P=0.07), indicating that there was not a significant reduction in cooling with progressive depth into the brain.
  
  
  CONCLUSIONS
  Convective head cooling reduced MRS brain temperature and core brain was cooled.
authors.affiliation: School of Clinical Sciences and Community Health, University of Edinburgh, Edinburgh, UK. b.harris@ed.ac.uk
authors.forename: B A
authors.initials: BA
authors.lastname: Harris
authors.forename: P J D
authors.initials: PJ
authors.lastname: Andrews
authors.forename: I
authors.initials: I
authors.lastname: Marshall
authors.forename: T M
authors.initials: TM
authors.lastname: Robinson
authors.forename: G D
authors.initials: GD
authors.lastname: Murray
mesh_terms: D000328:Adult; D001831:Body Temperature; D001921:Brain / Q000502:physiology*; D004947:Esophagus / Q000502:physiology; D005260:Female; D005542:Forearm / Q000502:physiology; D006257:Head; D006801:Humans; D007036:Hypothermia, Induced / Q000295:instrumentation / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D008875:Middle Aged; D009333:Neck; D010865:Pilot Projects; D012768:Shivering; D012881:Skin Temperature