Which statement correctly identifies iodinated contrast used in myelography?

• A. Ionic solutions are used
• B. Non-ionic solutions are used
• C. Barium is used
• D. Gadolinium is used

Answer: (B)

In myelography, the contrast medium must be iodinated and water-soluble so it can be injected into the subarachnoid space and appear clearly on radiographs. Among iodinated options, non-ionic contrasts are preferred because they have lower osmolality, which reduces irritation and adverse reactions in the CSF and surrounding neural tissues. Ionic iodinated contrasts, while radiopaque, come with higher osmolality and greater risk of adverse effects, making them less suitable for intrathecal use. Barium isn’t used intrathecally because it’s not water-soluble in CSF and can provoke inflammatory reactions like arachnoiditis; gadolinium-based agents are mainly used for MRI, not standard CT myelography. So the best choice is non-ionic iodinated contrast.