Diffusion-tensor imaging in septo-optic dysplasia.

One of the morphological correlates of septo-optic dysplasia is hypoplasia of the optic nerves. As of now, it remains unknown, in how far this disorder also affects the organization of the optic radiation. Using diffusion-tensor imaging (DTI), the non-invasive evaluation of large fiber tracts including the optic radiation has become possible. We have compared DTI-data from a patient suffering from septo-optic dysplasia with those of a group of eleven healthy control subjects. The anisotropy showed statistically significant reduction in the patient with septo-optic dysplasia within the visual fiber tracts and an unordered eigenvector map. A comparison of the anisotropy in the pyramidal tract showed no significant difference. Since the patient was congenitally blind, it remains unclear whether the findings are the results of the underlying disorder or occur in all congenitally blind patients. One might presume, that, in order for the optic radiation to fully develop, an afferent input to the lateral geniculate body is necessarry.