Efficacy of three-dimensional fast spin echo t2-weighted magnetic resonance imaging (cube) for evaluating the longitudinal spread of perihilar cholangiocarcinoma after endoscopic biliary stenting: a diagnostic study.

Background: Although accurate assessment of the longitudinal tumor spread is vital for the resection of perihilar cholangiocarcinoma (PHC), endoscopic biliary stent (EBS) placement can make imaging difficult. This study evaluated the diagnostic performance of three-dimensional fast spin-echo T2-weighted MRI (Cube) compared with multidetector computed tomography (MDCT) for determining PHC extension before and after EBS placement.

Materials and methods: This retrospective study included 91 patients who underwent surgical resection for PHC at a single center between 2016 and 2024 with available Cube and MDCT data. Four imaging scenarios were analyzed for each patient: MDCT without EBS, MDCT + EBS, Cube without EBS, and Cube + EBS. Radiological findings were compared with the pathological reference standard. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were calculated for each scenario. Inter-reader agreement was determined using Cohen's kappa coefficient.

Results: MDCT without EBS showed 79.1% accuracy in defining tumor extension, which dropped significantly to 30.2% after EBS placement (p<0.0001). Cube imaging showed 77.3% accuracy without EBS and 70.7% accuracy with EBS, significantly higher than MDCT with EBS (p<0.0001). The evaluability rate of MDCT decreased from 98% to 37% after stenting, whereas Cube retained an 85% evaluability rate with EBS. The inter-reader agreement was moderate to substantial for MDCT without EBS (κ = 0.74) and Cube without EBS (κ = 0.72) but declined for MDCT with EBS (κ = 0.34).

Conclusion: Cube may be the preferred choice to guide surgical planning for PHC in patients without high-quality MDCT images before stent placement,. Collectively, these findings suggest that Cube could bring about a paradigm shift in imaging-based diagnosis of PHC.