[Demyelinating diseases in childhood: diagnostic contribution of magnetic resonance].

Magnetic resonance imaging (MRI) exhibits a high sensitivity to detect white matter alteration but lacks specificity to characterize the disorder. We focus on the differential MR finding In two supposed autoimmune demyelinating diseases: multiple sclerosis (MS) and acute disseminated encephalomyelitis (ADEM). In ADEM, the associated finding of T2 prolongation in deep gray matter, specially the thalamic involvement, is a useful distinguishing feature. Given that ADEM is usually a monophasic disease the lesional enhancement should be homogeneous, and new lesions would not be expected to occur in serial MRI. Advances in neuroimaging of myelin disorders are intended for improve the resolution and sensitivity of MRI and for research new techniques to quantify lesion load and to monitor demyelination and neuronal damage.