Heterogeneity of brain glucose metabolism in mild cognitive impairment and clinical progression to Alzheimer disease.
BACKGROUND
Subjects with amnesic mild cognitive impairment (aMCI) may include patients at high risk for progression to Alzheimer disease (AD) and a population with different underlying pathologic conditions.


OBJECTIVE
To evaluate the potential roles of positron emission tomography with fluorodeoxyglucose F 18 (18FDG-PET) and memory scores in identifying subjects with aMCI and in predicting progression to dementia.


METHODS
Sixty-seven patients at European centers for neurologic and AD care who were diagnosed as having aMCI each underwent an extensive clinical and neuropsychological examination and an 18FDG-PET study. Forty-eight subjects were followed up periodically for at least 1 year, and progression to dementia was evaluated.


METHODS
Brain glucose metabolism and memory scores.


RESULTS
Fourteen subjects with aMCI who converted to AD within 1 year showed bilateral hypometabolism in the inferior parietal, posterior cingulate, and medial temporal cortex. Subjects with "stable" aMCI presented with hypometabolism in the dorsolateral frontal cortex. The severity of memory impairment, as evaluated by the California Verbal Learning Test-Long Delay Free Recall scores, correlated with the following brain metabolic patterns: scores less than 7 were associated with a typical 18FDG-PET AD pattern, and scores of 7 or higher were associated with hypometabolism in the dorsolateral frontal cortex and no progression to AD.


CONCLUSIONS
These data provide evidence for clinical and functional heterogeneity among subjects with aMCI and suggest that 18FDG-PET findings combined with memory scores may be useful in predicting short-term conversion to AD.
Anchisi
Davide
D
Istituto di Ricovero e Cura a Carattere Scientifico San Raffaele, Milan, Italy.
Borroni
Barbara
B
Franceschi
Massimo
M
Kerrouche
Nasser
N
Kalbe
Elke
E
Beuthien-Beumann
Bettina
B
Cappa
Stephano
S
Lenz
Olaf
O
Ludecke
Stephan
S
Marcone
Alessandra
A
Mielke
Rüdiger
R
Ortelli
Paola
P
Padovani
Alessandro
A
Pelati
Oriana
O
Pupi
Alberto
A
Scarpini
Elio
E
Weisenbach
Simon
S
Herholz
Karl
K
Salmon
Erik
E
Holthoff
Vjera
V
Sorbi
Sandro
S
Fazio
Ferruccio
F
Perani
Daniela
D
D000368:Aged; D000544:Alzheimer Disease / Q000209:etiology* / Q000378:metabolism; D001931:Brain Mapping; D016022:Case-Control Studies; D003072:Cognition Disorders / Q000378:metabolism*; D003710:Demography; D018450:Disease Progression; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000378:metabolism; D005500:Follow-Up Studies; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods; D011581:Psychological Tests / Q000706:statistics & numerical data; D012372:ROC Curve
D019788:Fluorodeoxyglucose F18; D005947:Glucose