title: Cerebral oxygen metabolism in patients with early Parkinson's disease.
abstract: OBJECTIVE
  Decreased activity of the mitochondrial electron transport chain (ETC) has been implicated in the pathogenesis of Parkinson's disease (PD). This model would most likely predict a decrease in the rate of cerebral oxygen consumption (CMRO(2)). To test this hypothesis, we compared CMRO(2) and cerebral blood flow (CBF) PET scans from PD patients and healthy controls.
  
  
  METHODS
  Nine early-stage PD patients and 15 healthy age-matched controls underwent PET scans for quantitative mapping of CMRO(2) and CBF. Between-group differences were evaluated for absolute data and intensity-normalized values.
  
  
  RESULTS
  No group differences were detected in regional magnitudes of CMRO(2) or CBF. Upon normalization using the reference cluster method, significant relative CMRO(2) decreases were evident in widespread prefrontal, parieto-occipital, and lateral temporal regions. Sensory-motor and subcortical regions, brainstem, and the cerebellum were spared. A similar pattern was evident in normalized CBF data, as described previously.
  
  
  CONCLUSIONS
  While the data did not reveal substantially altered absolute CMRO(2) in brain of PD patients, employing data-driven intensity normalization revealed widespread relative CMRO(2) decreases in cerebral cortex. The detected pattern was very similar to that reported in earlier CBF and CMRglc studies of PD, and in the CBF images from the same subjects. Thus, the present results are consistent with the occurrence of parallel declines in CMRO(2), CBF, and CMRglc in spatially contiguous cortical regions in early PD, and support the hypothesis that ETC dysfunction could be a primary pathogenic mechanism in early PD.
authors.affiliation: Deparment of Nuclear Medicine, Aarhus University Hospital, Denmark. per@pet.auh.dk
authors.forename: Per
authors.initials: P
authors.lastname: Borghammer
authors.forename: Paul
authors.initials: P
authors.lastname: Cumming
authors.forename: Karen
authors.initials: K
authors.lastname: Østergaard
authors.forename: Albert
authors.initials: A
authors.lastname: Gjedde
authors.forename: Anders
authors.initials: A
authors.lastname: Rodell
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Bailey
authors.forename: Manoucher S
authors.initials: MS
authors.lastname: Vafaee
mesh_terms: D000368:Aged; D001921:Brain / Q000098:blood supply / Q000378:metabolism*; D002560:Cerebrovascular Circulation / Q000502:physiology; D042241:Early Diagnosis; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology*; D010300:Parkinson Disease / Q000175:diagnosis* / Q000378:metabolism* / Q000503:physiopathology; D049268:Positron-Emission Tomography / Q000379:methods