High performance liquid chromatography with multiwavelength detection: a technique for identification of iodinated x-ray contrast agents in human body fluids and brain tissue.

PURPOSE Several cases of a severe adverse reaction, referred to as "ascending tonic-clonic seizure syndrome," have been reported after administration of water-soluble iodinated x-ray contrast agents for myelographic examinations. Because of the bizarre reactions, the identities of the causative contrast media were questioned.

METHODS Analyses of biologic materials from four of these patients were performed by using reverse-phase high-performance liquid chromatography. The chromatographic system was equipped with a fast-scanning UV-visible detector for the analysis of the UV-spectra of the chromatographic peaks.

RESULTS The analyses revealed that the nonionic contrast agents iohexol or ioversol were not present in detectable amounts in any of the samples. On the other hand, the chromatographic analyses revealed peaks that cochromatographed with and showed the same UV-spectra as the ionic agents diatrizoate, metrizoate, and ioxitalamate.

CONCLUSION The results indicate inadvertent injection of ionic contrast medium in all four cases.