title: Gender differences in cerebellar metabolism: test-retest reproducibility.
abstract: OBJECTIVE
  The purpose of this study was to evaluate gender differences in baseline measures of regional brain metabolism and to assess their reproducibility.
  
  
  METHODS
  Fifteen male and 13 female healthy subjects, whose mean age was 44 years, were tested with positron emission tomography and [18F]fluorodeoxyglucose (FDG) under resting conditions; eight of the men and 11 of the women underwent a second FDG scan under the same conditions 4-6 weeks later to assess the reproducibility of the previous results.
  
  
  RESULTS
  There were no differences in whole brain metabolism between the women and the men. In the first evaluation the female subjects showed significantly higher metabolism in the temporal poles and cerebellum than the male subjects. During the second evaluation the female subjects had significantly higher metabolism only in the cerebellum.
  
  
  CONCLUSIONS
  This study documents significant and reproducible gender differences in cerebellar metabolism; their functional significance merits further evaluation.
authors.affiliation: Department of Psychiatry, State University of New York at Stony Brook, USA. volkow@brain.med.bnl.gov
authors.forename: N D
authors.initials: ND
authors.lastname: Volkow
authors.forename: G J
authors.initials: GJ
authors.lastname: Wang
authors.forename: J S
authors.initials: JS
authors.lastname: Fowler
authors.forename: R
authors.initials: R
authors.lastname: Hitzemann
authors.forename: N
authors.initials: N
authors.lastname: Pappas
authors.forename: K
authors.initials: K
authors.lastname: Pascani
authors.forename: C
authors.initials: C
authors.lastname: Wong
mesh_terms: D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging / Q000378:metabolism; D002531:Cerebellum / Q000000981:diagnostic imaging / Q000378:metabolism*; D003847:Deoxyglucose / Q000031:analogs & derivatives / Q000378:metabolism; D005260:Female; D019788:Fluorodeoxyglucose F18; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D008297:Male; D015203:Reproducibility of Results; D012737:Sex Factors; D013702:Temporal Lobe / Q000000981:diagnostic imaging / Q000378:metabolism; D014055:Tomography, Emission-Computed
chemical_list: D019788:Fluorodeoxyglucose F18; D003847:Deoxyglucose; D005947:Glucose