Diabetes Mellitus–Related Fractional Glucose Uptake in Men and Women Imaged With (18)F-FDG PET-CT

CONTEXT: Cohort studies show that cognitive dysfunction and both vascular and Alzheimer’s dementia are more common in patients with type 2 diabetes mellitus (T2DM). OBJECTIVE: To review and compare brain volume and (18)F-fluorodeoxyglucose (FDG) uptake in brain of individuals age 60 to 70 years with or without type 2 diabetes. DESIGN: We searched 620 medical records for negative (18)FDG PET-CT scans obtained during 33 months. Records showing history of cognitive impairment, Alzheimer’s disease, neurologic disorders, any history of brain atrophy, or documented cerebral infarction on neuroimaging were excluded from the study. RESULTS: A total of 119 medical records met the inclusion criteria. Data from 63 women and 56 men (without T2DM, 86; with T2DM, 33) were analyzed. Brain volume was larger in men than women (mean ± SD, 1411 ± 225 cm(3) vs 1325 ± 147 cm(3), respectively; P = 0.02), but men had a significantly lower fractional glucose uptake (SUV(gluc)), calculated as fasting blood glucose × SUV(max.) [median (minimum, maximum), 63.6 (34.6, 126.6) vs 70.0 (36.4, 134.3); P = 0.02]. Brain volume was also larger in persons without T2DM than in those with T2DM (1392 ± 172 cm(3) vs 1269 ± 183 cm(3); P < 0.001), but SUV(gluc) was similar between these groups. Brain volume correlated with SUV(gluc) in both men and women overall (P < 0.001) but not in men and women with T2DM (P = 0.20 and 0.36, respectively). CONCLUSION: In men without T2DM, median brain volume was larger and fractional glucose uptake was less than in women without T2DM. In men and women with T2DM, brain volume and fractional glucose uptake were similar. The findings support the hypothesis that fractional glucose uptake becomes impaired in men with T2DM.