Comparison of side effects during cerebral computed tomography with a nonionic (iohexol) and an ionic (metrizoate) contrast medium.

Cerebral computed tomography was performed in 60 patients referred for pre- and postcontrast scanning. The patients were randomly sampled with a nonionic contrast medium, iohexol, and an ionic contrast medium, sodium metrizoate. No complications were seen, and the adverse effects, usually a feeling of warmth, were very minor with both contrast media, but iohexol caused less discomfort than sodium metrizoate. A series of measurements of the attenuation values of well defined intracranial structures was performed and no difference in enhancement was found between the two contrast media.