The other trial evaluating the effect of oral minocycline on TSPO binding in humans was conducted in traumatic brain injury and it compared the effect of minocycline in seven cases to placebo in five cases, finding a significant 20% reduction of TSPO distribution volume (TSPO VT), an index of TSPO density, in gray matter and white matter regions as measured with [11C]PBR28 PET19. Here, TSPO is linked to injury.