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 ADCHigh and ADCLow 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 ADCLow group tended to have a higher rate of advanced stage disease (P=0.09). Disease-free survival and overall survival (OS) of the ADCLow group were worse compared with the ADCHigh 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.