title: Age related preservation and loss in optimized brain SPECT.
abstract: BACKGROUND
  Recent single photon emission computed tomography (SPECT) studies have reported age related increases in regional brain perfusion (called preservation here) as well as losses.
  
  
  OBJECTIVE
  To apply optimized SPECT processing to better define and understand both age related preservation and loss in brain SPECT.
  
  
  METHODS
  Brain SPECT was performed on 85 healthy subjects using Tc hexamethylpropylene amine oxime (HMPAO), processed using findings from recent optimization work, and subjected to voxel based statistical analysis.
  
  
  RESULTS
  SPECT preservation was seen in white matter. This distribution differs from other SPECT reports, but is similar to that for preservation observed with structural magnetic resonance imaging (MRI). This suggests that SPECT preservation may arise from age related changes in brain anatomy, not regional cerebral blood flow (rCBF), and we demonstrate that it can arise from the partial-volume effect in areas where white matter contracts with age. Age related losses extended over the whole pre-frontal midline area and an extended pattern of focal losses was seen in the peripheral cortex that was consistent with major sulci. There were also focal losses in the cerebellum. The most significant SPECT loss was in the anterior cingulate, although no structural changes were observed there in the MRI study. A model of sulcal widening at the junction of the inter-hemispheric fissure and cingulate sulcus, when degraded by the partial-volume effect, could explain this anterior cingulate loss.
  
  
  CONCLUSIONS
  Optimized processing has revealed spatial patterns for age related preservation and losses in brain SPECT that indicate their origin is primarily structural. Correction for structural effects in optimized SPECT is needed to confirm whether any regional ageing effects derive from changes in rCBF.
authors.affiliation: Department of Nuclear Medicine, The Queen Elizabeth Hospital, Adelaide, South Australia, Australia. Leighton.Barnden@nwahs.sa.gov.au
authors.forename: Leighton R
authors.initials: LR
authors.lastname: Barnden
authors.forename: Setayesh
authors.initials: S
authors.lastname: Behin-Ain
authors.forename: Richard
authors.initials: R
authors.lastname: Kwiatek
authors.forename: Rey
authors.initials: R
authors.lastname: Casse
authors.forename: Lisa
authors.initials: L
authors.lastname: Yelland
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D016477:Artifacts; D001921:Brain / Q000098:blood supply* / Q000000981:diagnostic imaging* / Q000502:physiology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D002648:Child; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008297:Male; D008875:Middle Aged; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D019690:Technetium Tc 99m Exametazime / Q000493:pharmacokinetics; D014018:Tissue Distribution; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*
chemical_list: D019275:Radiopharmaceuticals; D019690:Technetium Tc 99m Exametazime