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

Abstract

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 18F-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 18FDG 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 cm3 vs 1325 ± 147 cm3, respectively; P = 0.02), but men had a significantly lower fractional glucose uptake (SUVgluc), calculated as fasting blood glucose × SUVmax. [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 cm3 vs 1269 ± 183 cm3; P < 0.001), but SUVgluc was similar between these groups. Brain volume correlated with SUVgluc 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.

Brown adipose tissue and regulation of human body weight

“… 28 found that participants with detectable BAT had lower BMI, body fat mass, and abdominal fat area compared to those without detectable BAT. However, it should be noted that blood glucose, which may have been higher in the obese participants, 29 can compete with 18 F‐FDG and result in lower uptake measurements 32 …”

“…However, it should be noted that blood glucose, which may have been higher in the obese participants, 29 can compete with 18 F-FDG and result in lower uptake measurements. 32 Although several 18 F-FDG PET-CT imaging studies have been conducted to detect and quantify BAT in humans, it is difficult to perform objective comparisons. This is because these studies used different protocols, and experimental factors including the ambient temperature, the injected dose of 18 F-FDG and the time from 18 F-FDG injection to imaging can significantly influence the results.…”

“…However, it should be noted that blood glucose, which may have been higher in the obese participants, 29 can compete with 18 F‐FDG and result in lower uptake measurements. 32 …”