The role of diffusion-weighted imaging in differentiation of hepatic alveolar echinococcosis and intrahepatic cholangiocarcinoma

Objective: A technique is proposed for evaluating the utility of apparent diffusion coefficient (ADC) measurements in the differentiation of type 4 hepatic alveolar echinococcosis (HAE) from the mass-forming type of intrahepatic cholangiocarcinoma (IHCC), using diffusion-weighted magnetic resonance imaging (DW-MRI). Methods: This study, conducted from November 2013 to January 2015, was approved by the ethics committee of First Affiliated Hospital of Xinjiang Medical University. All patients were given written informed consent. A total of 11 patients underwent T1WI, T2 fat-saturation, and a respiratory triggered DWI sequence by a 1.5T MR imaging system. An experienced radiologist measured the ADC in both alveolar echinococcosis and cholangiocarcinoma lesions. DWI was performed with a b-value gradient of 0 and 600. The mean ADC values of type 4 hepatic alveolar echinococcosis were compared with those of mass-forming type cholangiocarcinoma, in order to determine variations between the two. Differences in ADC between lesion types were determined by using an independent samples t-test and a statistically significant (P < 0.05) difference was observed. Results: Mean ADC values for IHCC were 1.24 ± 0.23 × 10−3 mm2/s, which was significantly lower than the 1.71 ± 0.23 × 10−3 mm2/s observed for HAE. These results supported the use of this technique as a mechanism for lesion differentiation. Conclusions: Lower ADC in DW-MRI represents restricted diffusion. Due to multicellularity being higher in IHCC than HAE, the mean ADC values for IHCC were lower than for HAE