What does gliosis on a brain mri mean? a few scattered punctate foci of increased flow signal consistent with areas of gliosis are identified in the bilateral cerebral hemisphere?

This will depend on the device used and how the doctor reads them. Best to discuss your question with Dr who has seen both you and the scan.

Gliosis could be considered the brain's equivalent of scarring, and represents areas of prior pathology. This would require clinical correlation with your prior symptoms, as many potential causes. Discuss fully with the radiologist and your doctor.