A patient with serum creatinine 2.8 mg/dL (eGFR 22 mL/min/1.73m²) requires CT pulmonary angiogram for suspected massive PE. Regarding contrast-induced nephropathy (CIN) and gadolinium, the most evidence-based management is:

• A Use gadolinium-based contrast for CT — it avoids nephrotoxicity
• B Withhold IV contrast and perform VQ scan instead
• C Give IV iodinated contrast after adequate IV hydration — benefit outweighs risk in massive PE ✓
• D Administer N-acetylcysteine prophylaxis and use iso-osmolar contrast without IV hydration

Explanation

In life-threatening emergencies such as massive PE, the risk of withholding contrast for CTPA far outweighs the risk of CIN. IV iodinated contrast should be administered after optimising hydration. Gadolinium is contraindicated in severe CKD (eGFR <30) because it causes nephrogenic systemic fibrosis (NSF). V/Q scan is a viable alternative only when the patient is haemodynamically stable and can be transported safely. N-acetylcysteine provides no proven benefit (randomised trials negative), and hydration alone (without NAC) is the only evidence-based CIN prophylaxis.

Reference: Grainger & Allison's Diagnostic Radiology, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.