Differences in hippocampal metabolism between amnestic and non-amnestic MCI subjects: automated FDG-PET image analysis.
OBJECTIVE
The aim of this study was to assess whether 18F-fluorodeoxyglucose positron emission tomography differentiates amnestic (aMCI) from single-non-amnestic mild cognitive impairment (snaMCI) with executive dysfunction.


METHODS
Sixteen aMCI subjects (62% females, age 75+/-8 years) and 14 snaMCI subjects (71% females, age 74+/-6 years) underwent [18F]FDG-PET and clinical follow-up. Comparisons between MCI subgroups and with seven cognitively normal elderly subjects were performed using SPM2.


RESULTS
At baseline aMCI and snaMCI exhibited a similar pattern of hypometabolism, mostly in the posterior cingulate gyrus, as compared with controls. In the comparison between the MCI subtypes, the aMCI subjects showed reduced metabolism in the medial temporal lobes (MTL) (hippocampus, fusiform gyrus and amygdala). At follow-up 12 aMCI developed Alzheimer's disease (AD), while snaMCI had a heterogeneous course, including five subjects who developed Lewy body dementia.


CONCLUSIONS
The patterns of altered brain metabolism in aMCI and snaMCI subjects compared to controls are similar and do not provide evidence for making clinical distinctions between them. Comparison between the two MCI subtypes showed MTL hypometabolism in aMCI subjects, possibly reflecting the fact that most had prodromal AD.
Clerici
F
F
Center for Research and Treatment of Cognitive Dysfunctions, Institute of Clinical Neurology Department of Clinical SciencesUniversity of Milan, Luigi Sacco Hospital, Milan, Italy. francesca.clerici1@unimi.it
Del Sole
A
A
Chiti
A
A
Maggiore
L
L
Lecchi
M
M
Pomati
S
S
Mosconi
L
L
Lucignani
G
G
Mariani
C
C
D000368:Aged; D000647:Amnesia / Q000175:diagnosis / Q000473:pathology*; D001331:Automation; D003072:Cognition Disorders / Q000175:diagnosis / Q000473:pathology*; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000494:pharmacology*; D005947:Glucose / Q000378:metabolism; D006624:Hippocampus / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D020961:Lewy Body Disease / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D049268:Positron-Emission Tomography / Q000379:methods*; D013702:Temporal Lobe / Q000473:pathology
D019788:Fluorodeoxyglucose F18; D005947:Glucose