EEG frequency analysis in metrizamide radiography.

Computerized frequency analysis was used to quantitate the EEG effects of intrathecal metrizamide in 22 patients undergoing radiographic procedures. In comparison to baseline recordings, no changes were found immediately after the procedure, but a significant (p less than 0.001) shift to lower frequencies was seen at 16 to 26 hours. Individually significant changes were infrequent with lumbar myelograms or low-dose cisternograms and were most prominent in patients who had the combination of high metrizamide dose, cervical level, and a complex procedure with prolonged supine positioning.