Intracranial metrizamide following myelography.

Twenty patients were studied by cranial computed tomography within 24 hours of myelography with metrizamide (Amipaque) to determine the intracranial manifestations of the use of this nonionic water soluble contrast medium. The findings ranged from relative hypodensity of the white matter due to ventricular opacification and gray matter penetration of metrizamide, to apparent trans-ependymal migration of the contrast agent resulting in what we have termed "pseudohydrocephalus." Trans-ependymal migration in normal humans has not been previously described. We were unable to establish precise radiologic correlates with the neurologic complications which some of the patients developed.