In MS patients, significant differences in the uptake of a radioligand for TSPO were identified in specific regions of cortical GM areas compared to healthy controls; a recent study by Singhal et al. (2019) detected an increase in radioligand uptake in the hippocampus, amygdala, posterior cingulate, midcingulate, and rolandic operculum, indicating higher levels of microglial activation in these GM areas compared to healthy controls (Figure 2). Here, TSPO is linked to myeloid sarcoma.