MR findings in Murray Valley encephalitis.

Murray Valley encephalitis (MVE) is caused by a flavivirus related to West Nile and St. Louis encephalitis viruses. We report a case of MVE resulting in quadriplegia and respiratory failure. MR imaging demonstrated thalamic hyperintensity on T2-weighted images, with similar involvement of the red nucleus, substantia nigra, and cervical cord. These findings preceded serologic diagnosis and are similar to those of Japanese encephalitis. In the appropriate setting, thalamic T2 hyperintensity is suggestive of flavivirus infection.