<prompt> Acute disseminated encephalomyelitis ADEM is a white matter disease that is indistinguishable from multiple sclerosis by all exceptMonophasicRapidly lethalAssociated with brainstem and spinal cord diseaseAssociated with MRI lesions which may resolve  <response>: ADEM is a demyelinating disease of the brain ,brainstem and spinal cord that is indistinguishable from MS on MRI. However,it is monophasic, that is it occurs acutely on a single occasion and not in a recurrent fashion like MS. 