Utility of the Apparent Diffusion Coefficient Value in Differentiating Gallbladder Cancer from Chronic Cholecystitis with Wall Thickening

Background: Gallbladder carcinoma and chronic cholecystitis are commonly encountered in clinical practice. However, the differential diagnosis between the two diseases can be complicated. Purpose: The aim of this study was to explore whether the apparent diffusion coefficient (ADC) value can be used to differentiate gallbladder carcinoma (GBC) from chronic cholecystitis with wall thickening. Materials and Methods: Preoperative magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI) were performed on 15 patients with GBC and 18 patients with chronic cholecystitis. The signal intensity of the thickened gallbladder wall in DWI was visually evaluated. The mean ADC values of the thickened gallbladder wall were measured. Results: Among the 18 cases with chronic cholecystitis, the average wall thickness was 0.57 +/- 0.46 cm. In the 15 patients with GBC, the average wall thickness was 0.68 +/- 0.21 cm. Visually increased signal on high b-value DWI was not different between GBC (93%) and chronic cholecystitis (67%) (P > 0.05). Multiple-layer patterns of the thickened gallbladder wall were observed in patients with chronic cholecystitis (14/18) using DWI. Gallbladder cancer patients (10/15) showed a loss of the multiple-layer pattern of the thickened gallbladder wall. Loss of the multiple-layer pattern of the thickened gallbladder wall on high b-value images was more frequent (P < 0.05) in GBC than chronic cholecystitis. Sensitivity and specificity of loss of the multiple-layer pattern of the thickened gallbladder wall on high b-value images for gallbladder carcinoma were 67%/78%. The mean ADC values of patients with chronic cholecystitis and GBC were (1.30 +/- 0.29) x10(-3) mm(2)/s and (1.10 +/- 0.17)x10(-3) mm(2)/s, respectively (P < 0.05). Conclusion: DWI and ADC values can be helpful for differentiating GBC from chronic cholecystitis.