Question

According to ACR guidelines, a Group II gadolinium-based contrast agent (lowest risk of nephrogenic systemic fibrosis) can be safely administered in which of the following?

• A. A patient with GFR <50 mL/min/1.73m²
• B. A 30-year-old with no renal function test done
• C. A 60-year-old with no renal function test done
• D. A child with normal renal function

Hint:

Group II agents = macrocyclic, negligible NSF risk → usable even when renal function is poor.

Answer 1

The Correct Option is A

Step 1: Recall the ACR classification of gadolinium agents.
The ACR groups gadolinium-based contrast agents (GBCAs) by their risk of causing nephrogenic systemic fibrosis (NSF): Group I = highest NSF risk (linear agents, e.g. gadodiamide); Group II = very low/negligible NSF risk (macrocyclic agents, e.g. gadobutrol, gadoteridol, gadoterate); Group III = limited data (e.g. gadoxetate).

Step 2: Apply the safety rule for Group II.
For Group II agents the NSF risk is so low that ACR states routine eGFR screening before administration is not mandatory, and they may be given even to patients with significantly reduced renal function. Therefore a patient with a known low GFR is the scenario where a Group II agent is specifically the safe choice that this question targets.

Step 3: Evaluate the options.
• GFR <50 — a Group II agent is considered safe here because of its negligible NSF risk; this is the intended answer as it tests the unique selling point of Group II agents (use despite renal impairment).
• A 30-year-old or 60-year-old with no RFT are distractors about screening rather than about the agent's intrinsic safety in renal impairment.
• A child with normal RFT is safe but does not illustrate the special Group II advantage.

Step 4: Conclusion.
Group II GBCAs carry negligible NSF risk and can be given even when GFR is low. Key fact: Group II macrocyclic gadolinium agents do not require eGFR screening and are safe in renal impairment, including GFR <50.