Apparent Diffusion Coefficient and Its Standard Deviation from Diffusion-weighted Imaging to Differentiate Tumor-adjacent and Tumor-distant liver tissues in T3 staged Resectable Gallbladder Carcinoma

Abstract Background An extended cholecystectomy is generally recommended for patients with gallbladder carcinoma (GBC) at stage T2 or above, and involves cholecystectomy and a limited hepatic resection. It is important to differentiate tumor-adjacent and tumor-distant liver tissues before surgery for surgical strategies decision making. Diffusion-weighted imaging (DWI) can provide functional information by depicting the diffusion of water in biological tissue and can be quantitated by apparent diffusion coefficient (ADC). Our study aimed to evaluate feasibility of ADC and its standard deviation (ADCsd) to differentiate between tumor-adjacent and tumor-distant liver tissues in T3 staged resectable GBC. Methods A total of 41 consecutive patients with T3 staged resectable GBC were included in this retrospective study and divided into two sets with (n = 27) and without (n = 14) liver invasion. All patients underwent DWI at b-values of 0, 20, 50, 80, 100, 200, 400, 600, 800 and 1000 sec/mm2 with a 3.0-T magnetic resonance scanner before surgery. Mean ADC and ADCsd of tumor-adjacent and tumor-distant liver tissues were measured on DWI, and were compared by Mann-Whitney U tests. If there was a significant difference in any derived parameter, area under the receiver operating characteristic curve (AUC) was used to assess performance of this parameter for differentiating tumor-adjacent and tumor-distant liver tissues. Results In the set with liver invasion, mean ADC and ADCsd of tumor-adjacent liver tissue were lower than those of tumor-distant liver tissue when b = 0, 800 sec/mm2, and b = 0, 1000 sec/mm2, respectively (all P-values < 0.05). In the set without liver invasion, ADC and ADCsd at all b values had no statistical differences between tumor-adjacent and tumor-distant liver tissues (all P-values > 0.05). To differentiate tumor-adjacent from tumor-distant liver tissues in the set with liver invasion, AUCs of ADC were 0.687 (b = 0, 800 sec/mm2) and 0.680 (b = 0, 1000 sec/mm2), respectively; and those of ADCsd were 0.673 (b = 0, 800 sec/mm2) and 0.731 (b = 0, 1000 sec/mm2), respectively. Conclusions In patients with liver invasion by T3 staged GBC, ADC and ADCsd could have potential value in differentiating tumor-adjacent from tumor-distant liver tissues.