MR imaging and cholangiography show suboptimal performance for diagnosing ductal cholangiocarcinoma in primary sclerosing cholangitis patients.

Objectives: Our purpose was to evaluate the performance of MR imaging/cholangiography for ductal cholangiocarcinoma (CCA) diagnosis and to search for specific MR features of ductal CCA among primary sclerosing cholangitis (PSC) patients.

Methods: We retrospectively analyzed 31 patients from a single center, each with a diagnosis of PSC, and suspicion of ductal CCA. Ductal CCA had been suspected during multidisciplinary team meetings when high-grade biliary stenosis was associated with focal thickening of the biliary wall. Two radiologists blinded to clinical information and imaging history independently reviewed patients' MR examinations using a standardized model created for this study. Fisher's exact test and Student's t-test were used to analyze the population's characteristics. Fisher's exact test and the chi-square test were used to compare associations of categorical variables (each standard model's item) with the final diagnosis. Interobserver agreement was assessed by Cohen's κ coefficient.

Results: Our population had a mean age of 42.7 ± 13.6 years and included 68% males. The final diagnosis was ductal CCA for 14 patients, and inflammatory stenosis for 17 patients. For diagnosing CCA, MR imaging/cholangiography exhibited a sensitivity of 43-50% and specificity of 70-76%, with low positive predictive (58-60%) and negative predictive (62-63%) values. Interobserver agreement ranged from κ = 0.04-0.75. Univariate analysis revealed no significant association between individual MR imaging/cholangiography features and CCA diagnosis.

Conclusion: MR imaging/cholangiography showed suboptimal performance for ductal CCA diagnosis among PSC patients and we did not find any specific feature to distinguish ductal CCA from inflammatory stenosis.

Key Points: Question Diagnosing ductal cholangiocarcinoma in patients with primary sclerosing cholangitis remains challenging without known predictive MR imaging features. Findings MR imaging/cholangiography exhibited low sensitivity, specificity, and interobserver reliability for ductal cholangiocarcinoma diagnosis in primary sclerosing cholangitis and lacks reliability for distinguishing between benign and malignant strictures. Clinical relevance Diagnosing ductal cholangiocarcinoma in patients with primary sclerosing cholangitis remains challenging and our retrospective study demonstrates that MR imaging lacks reliability in distinguishing between benign and malignant high-grade strictures and did not find any specific MR feature of ductal CCA.