Does a Focal Nodular Hyperplasia (FNH) liver lesion require MRI with Eovist (gadoxetate disodium) contrast with and without contrast to confirm the diagnosis or can regular MRI contrast be used?

MRI with Hepatobiliary Contrast Agent (Eovist) is Superior for Confirming FNH Diagnosis

Gadoxetate disodium (Eovist) contrast-enhanced MRI is the preferred imaging modality for confirming Focal Nodular Hyperplasia (FNH) liver lesions due to its superior diagnostic accuracy of 88-99% compared to standard extracellular gadolinium contrast agents. 1

Diagnostic Accuracy of Different MRI Contrast Agents for FNH

Hepatobiliary Contrast Agents (Eovist/Gadoxetate disodium)

• Provides highest accuracy (88-99%) for diagnosing FNH in patients with incidentally discovered liver lesions 1
• Offers unique hepatobiliary phase imaging that significantly improves FNH characterization
• For differentiation between adenoma and FNH:
  • Low signal on hepatobiliary phase is 100% specific, 92% sensitive, and 97% accurate for hepatocellular adenoma 1
  • FNH typically shows hyperintensity or isointensity in the hepatobiliary phase 2

Standard Extracellular Gadolinium Contrast

• While useful for many liver lesions, lacks the specific hepatobiliary phase that is crucial for FNH diagnosis
• Cannot reliably differentiate FNH from hepatocellular adenoma in challenging cases
• May require additional imaging or even biopsy in indeterminate cases

Diagnostic Algorithm for FNH Confirmation

1. Initial detection: Ultrasound typically identifies the lesion but cannot definitively characterize it
2. Confirmation imaging: MRI with hepatobiliary contrast agent (Eovist)
   • Provides both dynamic vascular phases AND hepatobiliary phase
   • Hepatobiliary phase occurs approximately 20 minutes after injection 1
3. Key diagnostic features on Eovist-enhanced MRI:
   • Arterial phase: Strong hyperperfusion from center outward ("spoke-wheel" appearance) 1
   • Portal venous phase: Iso- or hyperintense compared to liver
   • Hepatobiliary phase: Hyperintense or isointense (critical differentiating feature) 2

Evidence-Based Advantages of Eovist MRI for FNH

• Combination of diffusion-weighted imaging (DWI) and hepatobiliary phase allows correct classification of lesions as benign or malignant in 91% of cases 1
• Visual strong uptake of FNH vs. hypointensity of hepatocellular adenomas in the hepatobiliary phase results in an accuracy of 92% 2
• Hepatobiliary phase imaging is superior to all other morphological and dynamic vascular criteria alone and in combination (accuracy 54-85%) 2

Important Clinical Considerations

• Inflammatory adenoma can mimic FNH on MRI and represents a potential diagnostic pitfall 1
• Some atypical FNH lesions may show hypointensity during hepatobiliary phase, particularly those with:
  • Large central scar
  • Substantial fat component
  • Abundant radiating fibrous septa 3
• MRI with hepatobiliary contrast can reduce the need for invasive diagnostic procedures like biopsy 4

Conclusion

For confirming FNH diagnosis, MRI with hepatobiliary contrast agent (Eovist/gadoxetate disodium) provides superior diagnostic accuracy compared to standard gadolinium contrast agents. The hepatobiliary phase is the critical differentiating feature that allows confident diagnosis without the need for biopsy in most cases.