Iohexol vs. Iopamidol for Myelography

Three hundred sixty-three patients undergoing myelography were examined on a random basis with either iohexol (179) or iopamidol (184). All patients underwent neurologic or psychological assessment before and after the examination; 100 patients also submitted to cardiovascular and hematologic tests. Sixty patients were examined with electroencephalography before and after myelography. Incidence and severity of side effects were carefully evaluated in all patients and, wherever possible, by an independent observer, who was not told which contrast medium had been used. Radiographic quality was independently estimated and graded and was equally adequate with both media. Both iohexol and iopamidol will, in competent hands, provide myelograms of good radiographic quality without producing any permanent adverse sequelae. Incidence and severity of adverse side effects were slightly but significantly less with iohexol than with iopamidol. Three patients of the 25 examined with iopamidol showed EEG evidence of neuronal excitability following myelography. None of the 35 examined with iohexol showed this change.