Clinical Scorecard: Evaluation of Functional Strictures in Primary Sclerosing Cholangitis Patients Through Hepatobiliary Contrast-Enhanced MRI: A Proof-of-Concept Investigation

At a Glance

Key Highlights

• Dominant strictures (DS) defined by lumen diameter thresholds on ERCP are difficult to apply to conventional T2-MRCP due to technical differences.
• The term 'potential functional stricture' (PFS) is proposed, defined by impaired gadoxetic acid excretion on 20-min hepatobiliary phase T1-weighted MRI, reflecting either true functional stricture or hepatocellular dysfunction.
• PFS diagnosis via GA-MRI shows promise for improved inter-reader agreement and prognostic value compared to DS or high-grade stricture (HGS) definitions on T2-MRCP.

Guideline-Based Recommendations

Diagnosis

• Use ERCP as the gold standard for diagnosing dominant strictures in PSC.
• Apply T2-MRCP with stricture severity grading (≥75% narrowing as high-grade stricture) cautiously due to limited clinical relevance.
• Consider gadoxetic acid-enhanced MRI (GA-MRI) with hepatobiliary phase imaging to identify potential functional strictures (PFS) based on impaired bile excretion.
• Exclude secondary sclerosing cholangitis and confounding liver diseases before confirming PSC diagnosis.

Management

• Early diagnosis and localization of dominant or functional strictures are critical to optimize management and prognosis.
• Orthotopic liver transplantation remains the only effective treatment for advanced PSC.
• In ambiguous cases or when clinically indicated, perform ERCP to further evaluate strictures.

Monitoring & Follow-up

• Monitor cholestatic symptoms and liver biochemistry (bilirubin, alkaline phosphatase) for changes suggestive of stricture development.
• Use serial imaging with GA-MRI and T2-MRCP to assess stricture progression and hepatocellular function.
• Evaluate for complications such as cholangiocarcinoma, gallbladder carcinoma, and hepatocellular carcinoma, especially in cirrhotic patients.

Risks

• Risk of cholangiocarcinoma and gallbladder carcinoma in PSC patients.
• Increased risk of colorectal cancer in PSC patients with concurrent inflammatory bowel disease.
• Potential for progression to portal hypertension and hepatic dysfunction within 10 to 15 years of diagnosis.

Patient & Prescribing Data

PSC patients undergoing diagnostic evaluation for biliary strictures and hepatic function assessment

Gadoxetic acid-enhanced MRI provides functional imaging to detect impaired bile excretion indicative of functional strictures or hepatocellular dysfunction, aiding in timely diagnosis and management decisions.

Clinical Best Practices

• Adopt a binary classification system using GA-MRI hepatobiliary phase to distinguish potential functional strictures (PFS) from no functional strictures (NFS).
• Integrate clinical, laboratory, and radiologic data for comprehensive assessment of stricture significance.
• Exclude secondary causes and confounding liver diseases rigorously before diagnosing PSC.
• Use high-quality imaging protocols and standardized definitions to improve inter-reader agreement and diagnostic accuracy.
• Consider ERCP selectively for confirmation or therapeutic intervention in cases with ambiguous imaging or clinical deterioration.

References

• American Association for the Study of Liver Diseases (AASLD) Guidelines
• European Association for the Study of the Liver (EASL) Guidelines
• International PSC Study Group Consensus
• Gadoxetic Acid-Enhanced MRI in Biliary Disorders