Can MRI contrast agents affect kidney function?

MRI Contrast Agents and Kidney Function

MRI contrast agents can affect kidney function, but the risk varies significantly based on the type of agent used, with macrocyclic gadolinium-based contrast agents having minimal nephrotoxicity compared to linear agents, especially in patients with normal renal function. 1

Risk Stratification Based on Contrast Type

Gadolinium-based contrast agents (GBCAs) are categorized into three groups based on their chemical structure and associated risks:

Group I (Highest Risk)

• Linear agents (gadopentetate dimeglumine, gadodiamide, gadoversetamide)
• Associated with highest risk of Nephrogenic Systemic Fibrosis (NSF)
• Should be avoided in patients with renal impairment

Group II (Low Risk)

• Macrocyclic agents (gadoterate meglumine, gadobutrol, gadoteridol)
• Extremely low risk of NSF even in patients with renal dysfunction
• Preferred agents for patients with any degree of renal impairment

Group III (Limited Data)

• Gadoxetate disodium (hepatobiliary agent)
• No unconfounded cases of NSF reported, but limited data in high-risk patients

Risk Based on Renal Function

The American College of Radiology recommends stratifying patients into risk categories:

eGFR (mL/min/1.73m²)	Risk Category
> 45	Low risk
30-45	Intermediate risk
< 30	High risk

Specific Kidney Concerns

Nephrogenic Systemic Fibrosis (NSF)

• Primary serious concern with gadolinium agents
• Characterized by severe and progressive skin induration
• Risk factors:
  • Acute or chronic severe renal insufficiency (GFR <30 mL/min/1.73m²)
  • Acute renal insufficiency due to hepato-renal syndrome
  • Perioperative liver transplantation period
  • Higher doses of contrast
  • Multiple exposures to Group I agents

Acute Kidney Injury

• Rare with Group II agents
• A 2013 study (RESCUE) showed that meglumine gadoterate (Gd-DOTA) did not affect renal function in patients with chronic kidney disease 2
• A 2022 study demonstrated no significant eGFR decrease in patients with severe kidney disease (eGFR <30 ml/min) who received gadoterate meglumine compared to those who did not receive contrast 3

Contrast Agent Selection for Patients with Renal Impairment

For Patients with Normal Renal Function

• Any approved GBCA can be used
• Macrocyclic agents (Group II) preferred due to lower gadolinium retention

For Patients with Moderate Renal Impairment (eGFR 30-45 mL/min/1.73m²)

• Use macrocyclic GBCAs (Group II)
• Use lowest diagnostic dose possible

For Patients with Severe Renal Impairment (eGFR <30 mL/min/1.73m²)

• Consider non-contrast alternatives when possible
• If contrast is necessary, use only macrocyclic agents (Group II)
• Use minimum necessary dose
• Consider prompt dialysis after the procedure for patients on dialysis

Practical Recommendations

1. Screen patients for renal function before administering any GBCA
2. Select appropriate contrast agent based on renal function:
   • Macrocyclic agents (Group II) for patients with any degree of renal impairment
   • Avoid linear agents (Group I) in patients with impaired renal function
3. Use minimum necessary dose to achieve diagnostic quality
4. Consider alternative imaging methods for patients with severe renal dysfunction
5. Ensure adequate hydration before and after contrast administration
6. Monitor renal function after contrast administration in high-risk patients

Important Caveats

• The safety profile of macrocyclic GBCAs is far more favorable than iodinated contrast used in CT imaging 1
• Higher doses of contrast increase the risk of adverse effects
• Multiple exposures to gadolinium-based contrast, especially Group I agents, increase risk
• FDA drug labeling for gadoterate meglumine (a Group II agent) notes that "acute kidney injury requiring dialysis has occurred with the use of GBCAs" in patients with chronically reduced renal function 4
• Consider gadolinium retention in tissues, which is lower with macrocyclic agents compared to linear agents 4

By following these guidelines and selecting appropriate contrast agents based on patient risk factors, the risk of kidney-related adverse events from MRI contrast can be minimized.