A PROSPECTIVE CLINICAL-TRIAL COMPARING METRIZAMIDE AND IOHEXOL FOR EQUINE MYELOGRAPHY

A prospective clinical trial comparing adverse postmyelographic effect s and myelographic quality of metrizamide and iohexol was conducted. U sing a predetermined, randomized assignment, 23 horses exhibiting neur ologic signs were administered either metrizamide (180 mgl/ml) or iohe xol (180 mgl/ml) via cerebellomedullary puncture. Each horse was evalu ated postmyelographically for adverse effects. Myelographic quality wa s assessed by a numerical scoring method. Adverse effects were observe d more frequently with metrizamide (21) compared with iohexol (6) myel ography (p < 0.05). Seizures, intensification of preexisting neurologi c signs and prolonged anesthetic recovery were the most common complic ations after myelography. There was no difference in myelographic qual ity (p > 0.05). We conclude that iohexol is safer than metrizamide for equine myelography and that quality myelograms can be obtained with e ither contrast medium.