Factors influencing apparent diffusion coefficient value in extrahepatic cholangiocarcinoma: A retrospective study.

Background: Most cases of extrahepatic cholangiocarcinoma (ECC) show various degrees of hyperintensity on diffusion-weighted imaging (DWI) and hypointensity on apparent diffusion coefficient (ADC). However, the factors influencing ADC values in ECC have not yet been explored extensively. Therefore, this study explored the independent factors influencing ADC values in ECC.

Methods: A total of 88 patients with ECC confirmed by surgical pathology were retrospectively assessed. All patients underwent abdominal magnetic resonance imaging (MRI) at 3.0 T and ADC values of the tumor were measured. The correlation between ADC values and multiple clinicopathological features in ECC was analyzed, and independent factors influencing the ADC values in ECC were explored further.

Results: The ADC value of the tumor showed a significant difference in different perineural invasion group (p = 0.048), microvascular invasion group (p = 0.001), vascular endothelial growth factor expression group (p < 0.001), lymphatic status group (p = 0.003), and differentiation degree (DD) group (p < 0.001). However, there were no significant differences in different sex (p = 0.715), tumor location (p = 0.659), and degree of T stage (p = 0.879). Moreover, ADC value was negatively correlated with microvascular density (r = -0.725, p < 0.001) and lesion size (r = -0.244, p = 0.023). Nevertheless, there was no correlation between ADC value and patient age (r = 0.026, p = 0.812). Further regression analysis indicated that ADC value was independently associated with pathological DD of ECC (R = 0.678, p < 0.001) but not with other clinicopathological factors (p > 0.05).

Conclusion: ADC value of ECC is independently correlated with pathological DD of ECC, indicating that ADC value is a potential imaging biomarker for predicting the degree of ECC malignancy.