Brain in Creutzfeldt-Jakob disease. FLAIR magnetic resonance imaging (MRI) scan of a section through the brain of a 47-old patient, showing hyperintensities around the area of the cortex and basal ganglia, suggestive of Creutzfeldt-Jakob disease (CJD). CJD is the result of virus-like prions (misfolded proteins) within the brain that cause vacuoles and plaques to form, making the brain spongy and killing off the tissue. Symptoms include dementia and sudden muscle contractions, leading to death. The similarly fatal cattle disease BSE (bovine spongiform encephalopathy) has now been linked to human CJD.