[Iotrolan versus iopamidol. A controlled double-blind study with lumbar myelography]

Within the frame work of lumbar myelography, 158 patients were entered in a double-blind study in order to test a dimeric contrast medium (iotrolan) against a monomeric one (iopamidol), both of them non-ionic. A three-step scheme was applied to evaluate the X-ray pictures with respect to contrast quality. Particular attention was paid to the visibility of details, i.e. the nerve root and its course, as well as to how well it could be distinguished in the nerve root sheath. On the basis of a high level of significance (P less than 0.05), comparison of the two contrast media showed no difference in contrast quality. Sixty-nine percent of the examinations using iotrolan resulted in excellent contrast quality, whereas the corresponding very good results using iopamidol lay at 76%. Twenty-nine percent of the patients examined with iotrolan and 27% of those examined with iopamidol showed side effects. Headache occurred most frequently, followed by nausea, dizziness and neck pain. Sixty percent of the patients suffering from postmyelographic reactions reported delayed headache, which occurred most often with iotrolan rather than iopamidol. As for manifestation of other postmyelographic side effects, there were no significant differences (P less than 0.05, Fischer's test) between the two groups of contrast media.