Radioisotope cisternography in acute viral encephalitis. A reappraisal.

Five cases of presumed acute viral encephalitis with convulsions were examined with radioisotope (RI) cisternography six and 24 hours after an intrathecal injection of 1 mCi of pentetic acid labeled with either ytterbium 169 or indium 111. All cases showed abnormalities with this study. The "cold" areas observed with RI cisternography were well correlated with abnormal foci on the EEG. Although the findings are nonspecific, the CSF dynamics and patency of the subarachnoid space are easily examined by RI cisternography without appreciable complications. It is a useful supplementary diagnostic method to depict the extent of lobar abnormalities of cerebral cortex, particularly at an early stage, that either narrow or obliterate subarachnoid space and CSF pathways.