CT evidence of grey matter calcification secondary to radiation therapy.

There are four previously reported cases of post-irradiation calcification in the basal ganglia as demonstrated on the conventional skull roentgenograms. We have described two additional cases with grey matter calcification, which were demonstrated 10 and 14 yr after radiation therapy for an optic glioma and a medulloblastoma, respectively. The calcification was clearly demonstrated on CT scan, although it was not apparent on the skull roentgenogram. The extract pathogenesis of this condition is not clear. It appears, however, to be related to radiation vasculitis of the small vessels of the brain with resultant hyalinization and calcification. A long-term follow up study would be necessary to evaluate the significance and implication of post-irradiation calcification of the grey matter. CT is the most sensitive method of demonstrating the intracranial calcification in vivo.