"Optimized analysis of positron emission tomography (PET) scans using the radiotracer 18-F fluorodeoxyglucose (FDG) can provide early information on Alzheimer's disease (AD) and other conditions, researchers report in the March issue of the
Journal of Nuclear Medicine.This approach, lead investigator Dr. Lisa Mosconi told Reuters Health, "allows one to accurately detect and classify different types of dementia, including AD, frontotemporal dementia, and Lewy body dementia, at the very mild stages of disease."
FDG-PET measures brain glucose metabolism, she added. "A decrease in this rate is indicative of brain cell dysfunction, and is associated with dementia."
Dr. Mosconi, of New York University School of Medicine, New York and colleagues analyzed FDG-PET scans taken of 548 subjects of whom 110 were elderly, but healthy. The remainder had either mild cognitive impairment (MCI) frontotemporal dementia (FTD), Alzheimer's disease (AD), or dementia with Lewy bodies (DLB).
Standardized disease-specific PET patterns correctly classified 94 per cent of the normal subjects, 95 per cent with AD, 92 per cent with DLB and 94 per cent with FTD.
An Alzheimer's PET pattern was seen in 79 per cent of the MCI patients who had deficits in multiple cognitive domains and 31 per cent of those with amnesic MCI. PET findings in MCI without memory deficits were heterogeneous, ranging from no hypometabolism to patterns related to those for FTD and DLB.
"By using our optimized FDG-PET analysis techniques, we improved upon the early and differential diagnosis of the major dementing disorders that affect the elderly," continued Dr. Mosconi.
"Because the incidence of these disorders is expected to increase dramatically as the baby-boom generation ages," she concluded, "accurate diagnosis becomes extremely important, particularly at the early and mild stages of dementia when life-style changes and therapeutic interventions are supposed to be most effective."
