Risk of Seizures After Myelography : Comparison of lohexol and Metrizamide 879

A parallel, double-blind, randomized study comparing iohexol and metrizamide-both 180 mg I/ml-in lumbar myelography was carried out in 60 consecutive patients. Eight to 15 ml of contrast medium were administered with the upper level at the middle thoracic column. A detailed neurologic examination was performed before and 24 hr after myelography. EEG recordings-evaluated visually and with fast Fourier transformation analysis-and somatosensory evoked responses were registered before, 6 hr after, and 24 hr after myelography. All patients were observed for adverse reactions for 24-48 hr. lohexol did not produce any epileptiform activity but epileptiform activity was detected in five patients receiving metrizamide. lohexol produced significantly less frequent and less severe EEG changes than did metrizamide both at visual evaluation (p < .0025) and at fast Fourier transformation analysis (p < .04). No Significant changes occurred in the early components of the somatosensory evoked potentials after either contrast medium. lohexol caused significantly (p < .002) less frequent and less severe adverse reactions than did metrizamide. The neurologic examination revealed no changes of clinical importance with either contrast agent.