[The comparison of the regional cerebral metabolism rate of glucose in Alzheimer's disease with mild cognitive impairment]

Abstract

Objective: To study the feature of regional cerebral metabolism rate of glucose (rCMRglc) of Alzheimer's disease (AD) and mild cognitive impairment (MCI) by positron emission tomography (PET) and the relationship between MCI and AD.

Methods: 13 AD patients, 10 MCI patients and 10 health volunteers as a control group (HC) were underwent 18F-fluoro deoxyglucose (18F-FDG)-PET scanning.

Results: (1) There was lightly decreasing of radioactivity of temporal lobe and parietal lobe in HC group, a little severer decrease in MCI group, markedly decrease of radioactivity of temporal lobe, parietal lobe and frontal lobe in AD group examined by naked-eye. (2) The rCMRglc of many parts of brain such as frontal lobe, including superior, middle and inferior frontal gyrus, orbital gyrus and rectus gyrus, temporal lobe, including superior, middle and inferior temporal gyrus, parietal lobe, including superior parietal lobe, supramarginal gyrus and angular gyrus, limbic system, including anterior cingulate gyrus, insular lobe, basal ganglions, including thalamus, caudate nucleus and amygdaloid nucleus decreased significantly in AD group, compared to MCI and HC groups (p < 0.05 to p < 0.001). (3) The rCMRglc of many parts of brain such as frontal lobe, temporal lobe, parietal lobe, limbic system, and basal ganglions in MCI group was lower than that in HC group, but not significantly (p > 0.05). Only that of the left caudate nucleus in MCI decreased significantly compared to that in HC group (p < 0.05).

Conclusion: Decreasing of rCMRglc of parietal lobe is sensitive in evaluating cognitive function, next one is temporal lobe, and then frontal lobe. The rCMRglc of frontal lobe, temporal lobe, parietal lobe, limbic system, and basal ganglions decreasing markedly indicates that global function decayed in AD patients. While the rCMRglc of those parts in MCI patients' brain decreases mildly. This indicates that MCI is the middle state of AD and HC. Decreasing of rCMRglc of the left caudate nucleus has a certain role in diagnosis of MCI.