Widespread Glial Activation in Primary Progressive Multiple Sclerosis Revealed by 18F-PBR06 PET: A Clinically...

A 64-year-old man with primary progressive multiple sclerosis (Expanded Disability Status Scale 3.5) underwent PET using 18F-PBR06, a second-generation 18-kDa translocator protein ligand targeting activated brain microglia and astrocytes. Voxel-by-voxel statistical comparison of patient's PET images (acquired 60-90 minutes postinjection) with a healthy control data set was performed to generate a 3-dimensional z-score map of increased radiotracer uptake, which showed widespread increased glial activation in normal-appearing cerebral white matter, white matter lesional and perilesional areas, brainstem and cerebellum. In contrast, patient's 3-T MRI scan showed only a few small white matter brain lesions without contrast enhancement.