OBJECTIVE:Liver Imaging Reporting and Data System category M (LR-M) is associated with a poor prognosis in intrahepatic cholangiocarcinoma (iCCA). However, the prognostic value of individual LR-M features across imaging modalities remains unclear. We aimed to determine, through intraindividual comparisons, whether the prognostic value of individual LR-M features differs between CT and MRI in patients with iCCA at risk for hepatocellular carcinoma. MATERIALS AND METHODS:This retrospective study included consecutive patients with cirrhosis or chronic hepatitis B who underwent curative-intent resection for iCCA and preoperative multiphasic CT and MRI between 2010 and 2019. CT and MRI images were reviewed in separate sessions ≥4 weeks apart. Cox proportional hazards regression analyses with and without adjustment for LI-RADS categorization (non-LR-M vs. single-modality LR-M or dual-modality LR-M) were performed to evaluate the associations of CT- and MRI-based targetoid and non-targetoid LR-M features and other variables with recurrence-free survival (RFS) and overall survival (OS). RESULTS:A cohort of 122 patients (mean age, 57.9 ± 10.4 years) was included. MRI demonstrated significantly higher frequencies than CT for targetoid (84.4% vs. 73.8%, P = 0.007) and non-targetoid features (43.4% vs. 20.5%, P < 0.001), resulting in a higher rate of LR-M categorization (90.2% vs. 81.1%, P = 0.003). In the multivariable analysis, CT-based targetoid features (hazard ratio [HR] = 2.31 for RFS, P = 0.010; HR = 1.85 for OS, P = 0.043) and MRI-based non-targetoid features (HR = 2.15 for RFS, P = 0.005; HR = 2.09 for OS, P = 0.008) were independently associated with poorer survival. After adjustment for LI-RADS categorization, MRI-based non-targetoid features remained independently associated with poorer RFS (HR = 1.76, P = 0.041) and OS (HR = 1.79, P = 0.038). Dual-modality LR-M designation was independently associated with poorer RFS (HR = 8.02, P = 0.042). CONCLUSION:The prognostic implications of LR-M features in iCCA vary by imaging modality and feature type. CT-based targetoid and MRI-based non-targetoid features were associated with poorer survival, and the associations between MRI-based non-targetoid features and survival remained significant after adjustment for LI-RADS categorization.
