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[P‐073]: Prediction of progression to dementia in patients with mild cognitive impairment combining FDG‐PET imaging with apolipoprotein E genotyping
Author(s) -
Grimmer Timo,
Drzezga Alexander,
Riemenschneider Matthias,
Lautenschlager Nicola,
Minoshima Satoshi,
Foerstl Hans,
Kurz Alexander
Publication year - 2005
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2005.06.147
Subject(s) - apolipoprotein e , dementia , medicine , memory clinic , genotyping , oncology , pathology , disease , genotype , gastroenterology , biology , biochemistry , gene
Background: Etiology and prognosis of mild cognitive impairment (MCI) are heterogeneous. Progression to dementia is frequently associated with Alzheimer’s disease (AD) pathology. Prediction of outcome is difficult on clinical grounds. Objective(s): To determine the predictive value of neurobiological markers of AD (FDG-PET and apoE genotype) for the progression from MCI to dementia. Methods: Patients with (MCI) defined by Mayo Clinic criteria were consecutively recruited in our memory clinic. All patients underwent F18-FDG-PET imaging and apoE genotyping. PET data was analyzed by an established observer-independent method. The pattern of metabolic impairment was evaluated by an experienced clinician. Significant hypometabolism in temporal, parietal or posterior cingulate areas were rated as consistent with AD. Patients were re-examined to determine the individual outcome, i. e. progression to dementia. Positive and negative predictive value (PPV and NPV) for apoE genotype and FDG PET alone and in combination were calculated. Results: 30 patients (14 female, 16 male) were included (baseline: age 70 /8 years; MMSE 27.2 1.7). 17 (57%) were apoE e4 carriers. FDG-PET was consistent with AD in 13 patients (43%). All patients were followed-up after 16 2 months. 12 patients (40%) had deteriorated to dementia. Of 17 apoE e4 carriers, 9 progressed to dementia. The PPV and NPV of the genetic marker were 53 % and 77 %, respectively. Of 13 patients with AD-typical PET, 11 were found to be demented at re-examination. The PPV and NPV of the imaging marker were 85 % and 94 %. respectively. All 8 patients who carried the e4 allele and had AD-typical PET findings were diagnosed with dementia at follow-up. On the other hand, all 8 patients who lacked both markers were still diagnosed with MCI. The combination of the apoE e4 allele and a PET scan suggestive of AD achieved a PPV and NPV of 100 %. Conclusions: ApoE genotyping and FDG-PET imaging both contribute to establishing the individual prognosis in patients with MCI. When used in combination these markers achieve very high positive and negative predictive values. These findings require confirmation in larger and less selected patient populations.