Exploring Gadolinium-Based Contrast Media for Retrograde Pyelography in the Context of Iodine Allergy

Iodinated contrast media can rarely cause severe allergic reactions during nonvascular urologic imaging procedures. Alternatives like gadolinium-based contrast may help mitigate this risk in susceptible patients. A 66-year-old woman with a documented iodine allergy presented with an obstructing stone in the right ureter. To avoid the risk of an allergic reaction, the decision was made to use an alternative non-iodinated contrast agent for retrograde pyelography prior to ureteral stent placement. Gadobenate dimeglumine, an MRI contrast agent, was diluted 50:50 with saline and utilized successfully to provide adequate opacification for safe stent placement without adverse reaction. The patient underwent repeat pyelography with gadobenate dimeglumine one month later during ureteroscopy without complication. This case demonstrates that diluted gadobenate can serve as an effective alternative to iodinated contrast media in patients at high risk of reaction to iodine-containing agents. While severe reactions to iodinated contrast are uncommon in nonvascular urologic procedures, they can still occur even with premedication. Gadolinium-based agents have been reported to provide sufficient opacification for most urologic interventions, though inferior radiographically to iodinated contrast. Further study on gadolinium efficacy and safety in this setting is warranted. However the present case supports gadobenate dimeglumine as a viable option for retrograde pyelography when allergy risk precludes iodinated contrast use.