Prognostic prediction of apparent diffusion coefficient obtained by diffusion-weighted MRI in mass-forming intrahepatic cholangiocarcinoma

Abstract

Background: We evaluated apparent diffusion coefficient (ADC) of diffusion-weighted image MRI as a prognostic factor for mass-forming intrahepatic cholangiocarcinoma (IHCC).

Methods: We enrolled 26 patients who had undergone hepatic resections for mass-forming-type IHCC in this study, and calculated their mean ADC, using diffusion-weighted image MRI (b: 0, 20, 800 seconds/mm² ; 1.5 T MRI). Patients were divided into the ADC^High and the ADC^Low groups at the median ADC value (n = 13 for both). We also immunohistochemically evaluated hypoxia-inducible factor (HIF)-1α in tumor tissue.

Results: Median age in the ADC^Low was older (P = .03), and showed significant higher rate of scirrhous tumor (P = .02). The 5-year overall survival rate in the ADC^Low group was significantly worse than in the ADC^High group (P = .04). In multivariate analysis, hilar tumor, portal vein invasion and low ADC were independent prognostic factors (P < .05). The ADC^Low group also had a higher rate of high HIF-1α expression than the ADC^High group (P < .05). Representative case of ADC^Low group showed rich stroma and high HIF-1α expression.

Conclusions: The ADC values in MRIs can predict IHCC prognosis, and correlated with stromal density and HIF-1α expression.

Keywords: apparent diffusion coefficient; hypoxia-inducible factor-1; intrahepatic cholangiocarcinoma; magnetic resonance imaging; prognostic prediction.