Name two major contraindications to iodinated contrast used in CT angiography.

• A. Diabetes mellitus with nephropathy.
• B. History of iodinated contrast allergy and severe chronic kidney disease (low eGFR).
• C. Pregnancy.
• D. Penicillin allergy.

Answer: (B)

When deciding about iodinated contrast for CT angiography, two clear red flags stop us from using it: a known history of reaction to iodinated contrast and severely reduced kidney function. A prior contrast allergy means the risk of an immediate hypersensitivity reaction is high, so clinicians either avoid the contrast or take special precautions. Severe chronic kidney disease, reflected by a low eGFR, raises the danger of contrast-induced nephropathy, potentially causing further kidney damage. In that situation, alternatives or careful risk–benefit planning are essential.

Diabetes with nephropathy raises kidney risk but is not an outright ban on contrast. Pregnancy is generally a precaution rather than a strict contraindication, depending on the clinical scenario. Penicillin allergy has no direct relevance to iodinated contrast.