A prospective clinical trial comparing metrizamide and iohexol for equine myelography.

This clinical study explores the comparison between two contrast mediums, metrizamide and iohexol, for equine myelography, focusing on their resulting side effects and quality of myelograms. The results exhibit that iohexol is safer than metrizamide, with no significant difference in the quality of myelograms.

Research Methodology

• The trial was a prospective clinical one, where the researchers planned the study before embarking on it.
• The study involved 24 horses which displayed neurologic symptoms. The horses were randomly given either metrizamide or iohexol, both at a concentration of 180 mgl/ml, through a cerebellomedullary puncture procedure.
• Following myelography, each horse was evaluated for any adverse effects. The quality of the resulting myelograms was assessed using a numerical scoring method.

Results of the Research

• The experiment findings showed more frequent side effects with the use of metrizamide, compared to iohexol. Pathological side effects like seizures, an increase in already existing neurological symptoms, and delayed recovery from anesthesia were the most commonly observed complications post-myelography.
• The analysis of the adverse effects demonstrated statistical significance with a p-value of less than 0.05. This suggests that horses given metrizamide are more likely to exhibit postmyelographic complications than those given iohexol.
• Although the adverse effects differed between the two contrast mediums, the quality of the resulting myelograms did not. The study found no significant difference in myelogram quality (p > 0.05) between those produced by metrizamide or iohexol.

Conclusion of the Study

• The researchers concluded from the trial that iohexol is a safer contrast medium to use for equine myelography than metrizamide. Despite the difference in safety, both substances provided similar quality myelograms.
• The results suggest a potential change in practice from utilizing metrizamide to iohexol for equine myelography might be beneficial, especially with regard to minimizing negative side effects.