From the Guidelines
For evaluating a hepatic lesion, MRI with contrast is generally recommended over MRI without contrast, as it provides superior characterization of liver lesions with an accuracy of 95% to 99% for diagnosis of hemangioma, accuracy of 88% to 99% for the diagnosis of FNH, and accuracy of 97% for diagnosis of HCC 1.
Key Considerations
- The use of contrast-enhanced MRI allows for the assessment of enhancement patterns, which is crucial for differentiating between benign and malignant lesions.
- A combination of diffusion-weighted imaging (DWI) and hepatobiliary phase (HBP) imaging can correctly classify lesions as benign or malignant in 91% of cases and provide exact characterization in 85% of cases 1.
- Gadoxetate-enhanced MRI has been shown to have high accuracy for the diagnosis of various liver lesions, including hemangioma, focal nodular hyperplasia (FNH), and hepatocellular carcinoma (HCC) 1.
Recommendations
- The standard protocol for MRI with contrast typically includes both pre-contrast and post-contrast sequences, using gadolinium-based contrast agents at a dose of 0.1 mmol/kg body weight.
- Multiple phases of contrast enhancement (arterial, portal venous, and delayed phases) should be obtained to assess the vascularity and washout characteristics of the lesion.
- In cases where gadolinium is contraindicated, hepatobiliary-specific contrast agents like Eovist/Primovist may be considered, or non-contrast MRI techniques like diffusion-weighted imaging can provide alternative assessment, though with somewhat reduced diagnostic accuracy compared to contrast-enhanced studies.
Clinical Scenarios
- For patients with a known history of extrahepatic malignancy, MRI with contrast is usually appropriate for the imaging of an indeterminate >1 cm liver lesion on initial imaging with US 1.
- For patients with known chronic liver disease, MRI with contrast is usually appropriate for the imaging of an incidental liver lesion >1 cm on US, noncontrast, or single-phase CT, or noncontrast MRI 1.
From the Research
MRI Techniques for Hepatic Lesions
- MRI has advantages over other imaging modalities in diagnosing focal hepatic masses, including the use of basic T1 and T2 weighted sequences, diffusion weighted imaging (DWI), and hepatobiliary gadolinium contrast agents 2
- The choice of contrast agent depends on the clinical situation and the question to be answered, with extracellular contrast agents (ECAs) providing excellent dynamic phase information and hepatobiliary agents (HBAs) useful for characterizing lesions with functioning hepatocytes 3
Contrast-Enhanced MRI
- Contrast-enhanced MRI using hepatocyte-specific contrast agents (HSCAs) improves lesion detection and characterization compared to other imaging modalities and MRI techniques 4
- HSCAs, such as gadoxetate disodium and gadobenate dimeglumine, have clinical indications, protocols, and emerging uses for characterizing benign and malignant focal liver lesions 4
Characterization of Indeterminate Liver Lesions
- Contrast-enhanced ultrasound (CEUS) is a useful problem-solving tool in the evaluation of liver lesions that are indeterminate on CT and MRI, helping to establish a confident diagnosis and determine the need for further invasive diagnosis or treatment 5
- CEUS can detect arterial phase hyperenhancement, differentiate between hepatocellular carcinoma and intrahepatic cholangiocarcinoma, and determine benign versus malignant tumor thrombus, among other uses 5
Contrast Agent Elimination
- Compensatory elimination of gadobenate ion via the hepatobiliary pathway may occur in cases of impaired renal function, potentially aiding in the prevention of nephrogenic systemic fibrosis (NSF) 6
- The recovery of gadobenate ion in the urine and bile of rats with occluded bile ducts or renal vessels was significantly higher than that in normal rats, suggesting compensatory elimination may be an effective means to overcome compromised renal or hepatobiliary elimination 6