Laszlo Vecsei, MD, PhD, DSc, University of Szeged, Szeged, Hungary, discusses how the use of PET imaging can help our understanding of multiple sclerosis (MS). Currently, in everyday clinical practice, only a small part of what is happening in the brain can be seen with MRI. However, with the multitude of PET markers, many things such as microglial activity can be investigated. Using this method, the relationship between cerebral spinal fluid (CSF) and microglial activity in the hippocampus can be evaluated. This interview took place during the Virtual World Congress on Controversies in Neurology (CONy) 2020.