Credit: ZEPHYR / SCIENCE PHOTO LIBRARY

Caption: Acute disseminated encephalomyelitis. Coloured magnetic resonance imaging (MRI) scan of an axial section through the brain of a 56-year-old patient with acute disseminated encephalomyelitis (ADEM) following a viral infection. ADEM is a rare autoimmune disease characterised by widespread inflammation of the brain and spinal cord. It causes destruction of the white matter of the brain and is often triggered by a viral infection or vaccination.