Influence of intrathecally used contrast dye (Iotrol) on cerebral cortical activities.

-Quantitative EEG study-

Abstract

The potential neurotoxicity of Iotrol used in cervical myelography was determined by examining three criteria; clinical symptoms, EEG recordings with frequency analysis (by quantitative EEG study), and CT scan of the brain of 25 patients. The CT observation informed how far the contrast dye diffused into the subarachnoid spaces. Clinical symptoms developed in two patients with EEG abnormalities; in one case, hallucination (visual) appeared, and other, headache. Two other patients showed EEG abnormalities without clinical symptoms. Such abnormalities diminished within a week. Quantitative EEG study showed increased delta activities, most frequently in the left O area (p<0.05-0.10), as well as decreased alpha activities mostly the left O area (p<0.05). We conclude that quantitative EEG study is very important in the evaluation of neurotoxicity of contrast dye to central nervous system, especially among patients who show penetration of the dye into brain parenchyma, and that EEG recordings obtained 3-4 hrs after injection can be used to predict adverse effects which may appear more than 24 hrs later.