Cerebral metabolic changes accompanying conversion of mild cognitive impairment into Alzheimer's disease: a PET follow-up study

Eur J Nucl Med Mol Imaging. 2003 Aug;30(8):1104-13. doi: 10.1007/s00259-003-1194-1. Epub 2003 May 23.

Abstract

A high percentage of patients with mild cognitive impairment (MCI) develop clinical dementia of the Alzheimer type (AD) within 1 year. The aim of this longitudinal study was to identify characteristic patterns of cerebral metabolism at baseline in patients converting from MCI to AD, and to evaluate the changes in these patterns over time. Baseline and follow-up examinations after 1 year were performed in 22 MCI patients (12 males, 10 females, aged 69.8+/-5.8 years); these examinations included neuropsychological testing, structural cranial magnetic resonance imaging and fluorine-18 fluorodeoxyglucose positron emission tomography (PET) evaluation of relative cerebral glucose metabolic rate (rCMRglc). Individual PET scans were stereotactically normalised with NEUROSTAT software (Univ. of Michigan, Ann Arbor, USA). Subsequently, statistical comparison of PET data with an age-matched healthy control population and between patient subgroups was performed using SPM 99 (Wellcome Dept. of Neuroimaging Sciences, London, UK). After 1 year, eight patients (36%) had developed probable AD (referred to as MCI(AD)), whereas 12 (55%) were still classified as having stable MCI (referred to as MCI(MCI)). Compared with the healthy control group, a reduced rCMRglc in AD-typical regions, including the temporoparietal and posterior cingulate cortex, was detected at baseline in patients with MCI(AD). Abnormalities in the posterior cingulate cortex reached significance even in comparison with the MCI(MCI) group. After 1 year, MCI(AD) patients demonstrated an additional bilateral reduction of rCMRglc in prefrontal areas, along with a further progression of the abnormalities in the parietal and posterior cingulate cortex. No such changes were observed in the MCI(MCI) group. In patients with MCI, characteristic cerebral metabolic differences can be delineated at the time of initial presentation, which helps to define prognostic subgroups. A newly emerging reduction of rCMRglc in prefrontal cortical areas is associated with the transition from MCI to AD.

Publication types

  • Clinical Trial
  • Comparative Study
  • Controlled Clinical Trial

MeSH terms

  • Aged
  • Alzheimer Disease / complications
  • Alzheimer Disease / diagnosis
  • Alzheimer Disease / diagnostic imaging*
  • Alzheimer Disease / metabolism*
  • Brain Mapping / methods
  • Cerebral Cortex / diagnostic imaging*
  • Cerebral Cortex / metabolism*
  • Cognition Disorders / complications
  • Cognition Disorders / diagnosis
  • Cognition Disorders / diagnostic imaging*
  • Cognition Disorders / metabolism*
  • Disease Progression
  • Female
  • Fluorodeoxyglucose F18 / pharmacokinetics*
  • Follow-Up Studies
  • Glucose / metabolism
  • Humans
  • Longitudinal Studies
  • Male
  • Neuropsychological Tests
  • Prognosis
  • Reproducibility of Results
  • Risk Assessment / methods
  • Sensitivity and Specificity
  • Severity of Illness Index
  • Statistics as Topic
  • Tomography, Emission-Computed / methods

Substances

  • Fluorodeoxyglucose F18
  • Glucose