TSPO and obesity due to melanocortin 4 receptor deficiency: However, recent multimodal PET study indicate that obesity is associated with increased cerebral metabolic activity and resting-state brain activity without corresponding increases in translocator protein (18 kDa; TSPO) availability, suggesting that PET-based markers of neuroinflammation may have limited sensitivity in detecting obesity-related inflammatory processes and should be interpreted with caution [134].