title: Alzheimer's disease: differences in technetium-99m HMPAO SPECT scan findings between early onset and late onset dementia.
abstract: OBJECTIVE
  To compare the HMPAO SPECT cerebral perfusion patterns in early and late onset Alzheimer's disease.
  
  
  METHODS
  Twenty patients with early onset disease (<65 years) and 44 patients with late onset disease (>65 years) were studied. All patients fulfilled NINCDS-ADRDA clinical criteria and had details of disease severity and length of history at the time of imaging. Technetium-99m HMPAO SPECT brain scans were acquired on a multi-detector gammacamera and analysed visually and with statistical parametric mapping (SPM99).
  
  
  RESULTS
  Patients with early onset disease had significantly greater posterior cortical association area involvement whereas those with late onset disease had significantly greater medial temporal hypoperfusion. These findings were unchanged after controlling for disease severity and length of illness.
  
  
  CONCLUSIONS
  These functional imaging findings of the differences between early and late onset Alzheimer's disease are supported by published findings that include histopathological and clinical evidence; namely late onset patients tend to present with the characteristic involvement of the medial temporal lobes producing marked memory loss whereas early onset patients present with predominant posterior cortical association area involvement. These age related findings should be borne in mind when clinically diagnosing, and interpreting functional brain imaging studies in, patients with suspected Alzheimer's disease.
authors.affiliation: Department of Nuclear Medicine, Southampton University Hospitals Trust, Southampton, UK. paul.kemp@suht.swest.nhs.uk
authors.forename: P M
authors.initials: PM
authors.lastname: Kemp
authors.forename: C
authors.initials: C
authors.lastname: Holmes
authors.forename: S M A
authors.initials: SM
authors.lastname: Hoffmann
authors.forename: L
authors.initials: L
authors.lastname: Bolt
authors.forename: R
authors.initials: R
authors.lastname: Holmes
authors.forename: J
authors.initials: J
authors.lastname: Rowden
authors.forename: J S
authors.initials: JS
authors.lastname: Fleming
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000000981:diagnostic imaging*; D001921:Brain / Q000000981:diagnostic imaging* / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000175:diagnosis; D008875:Middle Aged; D009483:Neuropsychological Tests; D010091:Oximes / Q000493:pharmacokinetics; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D012189:Retrospective Studies; D012720:Severity of Illness Index; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D010091:Oximes; D019275:Radiopharmaceuticals; C068296:hexamethylpropyleneamine oxime