The influence of obesity on cerebral blood flow in young adults using arterial spin labeling MRI

Obesity causes damage to several organs, including the brain. Recent studies have been focusing on understanding the mechanisms through which obesity affects brain structure and function using neuroimaging techniques. A functional biomarker, such as cerebral blood flow (CBF), is a powerful tool that can be used to explore neural dysfunction. However, there is currently limited information regarding the association between CBF and obesity. The study was conducted to investigate the potential effect of obesity on brain perfusion in a young cohort aged 20‐30 years. A total of 21 obese (body mass index (BMI) > 26 kg/m2) and 21 lean (BMI < 24 kg/m2) right‐handed volunteers were included in this study. CBF was acquired using the 2D single post‐labeling delay (PLD) arterial spin labeling (ASL) technique on a 3 T MRI scanner. A multiple regression analysis was performed to examine the difference in global and regional gray matter (GM) CBF between the groups. CBF value was assigned as the dependent variable, whereas age, sex, and group (obese or lean) were considered as the independent variables. Results showed that group‐related differences in CBF were homogeneous across brain regions, as obese subjects had significantly lower global GM CBF than lean subjects (P < 0.05). In the voxelwise analysis, obese individuals had significantly lower CBF in the left pulvinar of the thalamus and visual association areas, including Brodmann area (BA) 7, BA18, and BA19, than lean subjects. Although the signal‐to‐noise ratio was slightly compromised for 2D sequences and subject‐specific arterial transit time was not estimated due to a single PLD sequence, this study demonstrated alterations in CBF in obese subjects, particularly in regions of the pulvinar of the thalamus and its synchronously related areas such as visual association areas. These results suggest that ASL provides a potential platform for further obesity‐related research. Compared with lean subjects, obese individuals had lower cerebral blood flow (CBF) in the left pulvinar of the thalamus and visual‐associated areas, including Brodmann area (BA) 7, BA18, and BA19. The opposite result, ie lean subjects having lower CBF than obese individuals, was not detected. These findings suggest that ASL can provide a useful tool to further investigate obesity‐related diseases.