For an adult patient with intraductal tubulopapillary neoplasm of the bile ducts (ITPN‑B), which MRI contrast agent—Eovist (gadoxetate disodium) or Elucirem (gadopiclenol)—is preferred to best evaluate the lesion, considering the need for hepatobiliary phase imaging and renal function?

MRI Contrast Selection for ITPN-B Evaluation

For evaluating intraductal tubulopapillary neoplasm of the bile ducts (ITPN-B), Eovist (gadoxetate disodium) is the preferred contrast agent because it provides essential hepatobiliary phase imaging that allows visualization of the biliary tree and characterization of intraductal lesions, which is critical for detecting the papillary masses and assessing bile duct involvement characteristic of ITPN-B. 1, 2, 3

Rationale for Eovist Preference

Hepatobiliary Phase Imaging Advantage

• Eovist is a hepatobiliary-specific contrast agent that is taken up by functioning hepatocytes and excreted into the bile ducts, creating a delayed hepatobiliary phase (20-120 minutes post-injection) that provides direct visualization of the biliary tree. 2, 3
• This hepatobiliary phase acts as a contrast-enhanced cholangiography, where the bile ducts are opacified by the excreted contrast, making intraductal masses appear as filling defects against the bright bile—exactly what is needed to detect ITPN-B lesions. 3
• The combination of dynamic phases (arterial, portal venous) plus hepatobiliary phase imaging significantly improves diagnostic capability compared to conventional T2-weighted MRCP alone. 1, 3

ITPN-B-Specific Imaging Requirements

• ITPN-B characteristically presents as intraductal papillary masses with bile duct dilatation, and these lesions show mild enhancement in arterial phase with gradual delayed enhancement on dynamic imaging. 4, 5
• The intraductal solid components of ITPN-B appear as filling defects on MRCP, and Eovist's hepatobiliary phase enhances detection of these masses by providing superior contrast between the tumor and bile. 4, 3
• ITPN-B lesions can be extensive (often >20mm along the bile duct) and may show various morphologic patterns including diffuse bile duct dilatation, aneurysmal dilatation, or segmental dilatation—all better characterized with hepatobiliary phase imaging. 4, 5

Elucirem Limitations

• Elucirem (gadopiclenol) is a traditional extracellular gadolinium agent that does not provide hepatobiliary phase imaging, limiting its utility for biliary tree evaluation. 1
• Without hepatobiliary excretion, Elucirem cannot opacify the bile ducts or provide the contrast-enhanced cholangiography effect that is crucial for detecting and characterizing intraductal lesions like ITPN-B. 1, 3
• Elucirem would only provide standard dynamic contrast phases (arterial, portal venous, delayed), which are insufficient for optimal ITPN-B evaluation compared to the added value of hepatobiliary imaging. 1

Renal Function Considerations

Patients with Normal to Mild Renal Impairment (eGFR ≥30 mL/min/1.73m²)

• Eovist can be safely administered at the standard dose of 0.1 mL/kg (0.025 mmol/kg) in patients with eGFR ≥30 mL/min/1.73m². 2
• Gadolinium-based contrast agents like Eovist are not nephrotoxic and are safer than iodinated CT contrast in patients with mild renal insufficiency. 1

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

• Avoid Eovist in patients with severe kidney disease (GFR <30 mL/min/1.73m²) or acute kidney injury due to the risk of nephrogenic systemic fibrosis (NSF), unless the diagnostic information is essential and not available with non-contrast MRI. 2
• In patients with severe renal dysfunction, unenhanced MRCP using heavily T2-weighted sequences can still detect ITPN-B by showing intraductal masses as filling defects and demonstrating bile duct dilatation patterns. 6, 7, 4
• However, unenhanced MRCP lacks the dynamic enhancement patterns and hepatobiliary phase that improve lesion characterization and detection of smaller lesions. 3

Practical Imaging Protocol

Standard Eovist Protocol for ITPN-B

• Perform pre-contrast T1WI, T2WI with fat suppression, and conventional MRCP sequences first. 4
• Administer Eovist at 0.1 mL/kg as an intravenous injection at 1-2 mL/second. 2
• Obtain dynamic phases: arterial (15-25 seconds post-injection), portal venous (60 seconds), and equilibrium (120 seconds). 2
• Acquire hepatobiliary phase images at 20 minutes post-injection, which can be extended up to 120 minutes if needed. 2
• Include diffusion-weighted imaging (DWI), as ITPN-B lesions show restricted diffusion with lower ADC values compared to normal bile. 4

Special Considerations for ITPN-B

• If bilirubin is elevated (>3 mg/dL), perform hepatobiliary phase imaging no later than 60 minutes post-injection, as elevated bilirubin reduces hepatic contrast effect. 2
• Use 3D-reconstruction MRCP images to identify the relationship between aneurysmal bile duct dilatation and the main bile duct, which is characteristic of some ITPN-B cases. 4
• Look for associated findings including bile duct stones (present in 40% of ITPN-B cases), proximal and distal bile duct dilatation, and the absence of adjacent tissue invasion. 4

Common Pitfalls and Caveats

• Do not confuse ITPN-B with bile duct stones, sludge, or blood clots—the dynamic enhancement pattern (mild arterial enhancement with gradual delayed enhancement) and restricted diffusion on DWI help differentiate ITPN-B from these mimics. 4, 8
• ITPN-B can show atypical imaging findings mimicking chronic pancreatitis or cholangiocarcinoma in up to 37.5% of cases, so correlation with clinical context and consideration of lesion multiplicity is important. 9
• Screen patients for acute kidney injury before Eovist administration, particularly in elderly patients (>60 years), those with hypertension or diabetes, or those with recent surgery or severe infection. 2
• The intense enhancement rim at the base of intraductal masses during portal venous or delayed phases is a characteristic finding of ITPN-B that should be actively sought. 5