REGIONAL CEREBRAL FUNCTION DETERMINED BY FDG-PET IN HEALTHY-VOLUNTEERS - NORMAL PATTERNS AND CHANGES WITH AGE

The main objective of this study was to determine patterns of regional brain metabolic activity utilizing high-resolution PET in normal heal thy volunteers and variations in different age groups. Methods: High-r esolution [F-18]FDG PET images of the entire brain were obtained in 12 0 healthy normal volunteers (64 men, 56 women), age range from 19 to 7 9 yr. Each anatomic region was assessed using a qualitative rating sca le with a score ranging from 1 to 6 (1 = definitely normal and 6 = def initely abnormal). Local metabolic activity was also estimated as show ing increased (+) or decreased (-) compared to normal (0) states. Resu lts: The most consistent finding in normal aging was decreased cortica l metabolism, particularly in the frontal robes. Temporal, parietal an d occipital robe metabolism varied considerably among subjects within the same age group as well as over decades. Basal ganglia, hippocampal area, thalami, cerebellum, posterior cingulate gyrus and visual corte x remained metabolically unchanged with advancing age. Conclusion: The se data indicate that qualitative interpretation of FDG-PET images all ows accurate assessment of regional metabolic activity of the brain in normal subjects similar to those described with quantitative techniqu es. Adequate knowledge of normal variations and changes related to nor mal aging is necessary for optimal assessment of pathologic states.