Evaluation of malignancy in gallbladder tumors using the apparent diffusion coefficient obtained by diffusion‑weighted MRI.

The utility of the apparent diffusion coefficient (ADC) of diffusion-weighted image (DWI) magnetic resonance imaging was examined for evaluating malignancy and prognosis in gallbladder tumors. A total of 63 patients (benign tumors, n=33; cancer, n=30) were included after surgical resection for gallbladder tumors, and their mean ADC values by DWI were obtained. Cases of advanced gallbladder cancer (n=25) were divided into ADC High and ADC Low groups, and clinicopathological factors were compared. In 63 cases, ADC values in advanced gallbladder cancer were significantly lower compared with benign tumors and non-advanced gallbladder cancer (P<0.05), and ADC values in early gallbladder cancer were also significantly lower compared with benign tumors (P<0.05). In 25 advanced gallbladder cancer cases, the ADC Low group tended to have a higher rate of advanced stage disease (P=0.09). Disease-free survival and overall survival (OS) of the ADC Low group were worse compared with the ADC High group (P<0.01). In the multivariate analysis of OS, poor differentiation and low ADC value were independent prognostic factors. ADC values may be useful for evaluating tumor malignancies in gallbladder tumors.