Transsynaptic degeneration of lateral geniculate bodies in blind children: in vivo MR demonstration.

PURPOSE To investigate signal alterations in the thalamic lateral geniculate bodies of blind patients compatible with transsynaptic degeneration of these nuclei caused by pregeniculate or postgeniculate interruption of the visual pathway.

METHODS Six patients were selected from a group of blind children in our care. Four had cerebral palsy caused by periventricular leukomalacia, one had infantile neuroaxonal dystrophy, and one had Chiari I malformation and hydrocephalus, which was worsened by bilateral ischemic lesions of the occipital lobes. MR examinations (obtained at 0.5 T) were reviewed retrospectively by two neuroradiologists, with particular attention to the visual pathway.

RESULTS Symmetric, focal areas of T2 prolongation were found at the precise site of the lateral geniculate bodies.

CONCLUSION Anterograde (pregeniculate) and retrograde (postgeniculate) transsynaptic degeneration of the second neurons of the visual pathway produce alterations in MR signal.