Diagnostic Performance of Apparent Diffusion Coefficient Values for The Differentiation of Intrahepatic Cholangiocarcinoma from Gastrointestinal Adenocarcinoma Liver Metastases

BackgroundWe aimed to investigate whether there is a difference between intrahepatic cholangiocarcinoma (IHCC) and liver metastases of gastrointestinal system (GIS) adenocarcinoma in terms of apparent diffusion coefficient (ADC) values.Patients and methodsFrom January 2018 to January 2020, we retrospectively examined 64 consecutive patients with liver metastases due to gastrointestinal system adenocarcinomas and 13 consecutive IHCC in our hospital’s medical records. After exclusions, fifty-three patients with 53 liver metastases and 10 IHCC were included in our study. We divided the patients into two groups as IHCC and liver metastases of GIS adenocarcinoma. For mean apparent diffusion coefficient (ADC_mean) values, the region of interests (ROI) was placed in solid portions of the lesions. ADC_mean values of groups were compared.ResultsThe mean age of IHCC group was 62.50 ± 13.49 and mean age of metastases group was 61.15 ± 9.18. ADC_mean values were significantly higher in the IHCC group compared to the metastatic group (p < 0.001). ROC curves method showed high diagnostic accuracy (AUC = 0.879) with cut-off value of < 1178 x 10^-6 mm²/s for ADC_mean (Sensitivity = 90.57, Specificity = 70.0, positive predictive value [PPV] = 94.1, negative predictive value [NPV] = 58.3) in differentiating adenocarcinoma metastases from IHCC.ConclusionsThe present study results suggest that ADC values have a potential role for differentiation between IHCC and GIS adenocarcinoma liver metastases which may be valuable for patient management.Key words: cholangiocarcinoma, gatrointestinal system, liver metastases, apparent diffusion coefficient, diffusion weighted image, MRI