Although not visible on post-contrast T1 and pre-contrast FLAIR, there is extensive smooth thin sulcal enhancement on the more sensitive post-contrast FLAIR sequence. The CT is normal and the remainder of the MRI is normal.

Diffuse leptomeningeal enhancement is in-keeping with meningitis. The lumbar puncture demonstrated clear and colourless CSF with a CSF lymphocytosis. The gram stain and culture were negative. The differential in this case includes viral meningitis, or less likely TB or fungal meningitis.