In vivo gallbladder bile diffusion coefficient measurement by diffusion-weighted echo planar imaging in hamster fed normal and lithogenic diets

It is shown that in vivo measurement of bile water apparent diffusion coefficient (ADC) by diffusion-weighted echo-planar imaging (EPI) in hamster gallbladder is possible providing motion artifact-free ADC values. These ADC values are used to estimate bile viscosity variation induced by normal diets, cholesterol gallstone-inducing diets, and an antilithiasic drug, and to determine if a link exists between bile viscosity and cholesterol gallstone formation. Measurements were performed at 4.7 T with respiratory triggering in five groups of hamsters fed a commercial (RC) or a semisynthetic (SSD) diet, a SSD containing 0.2% hyodeoxycholic acid (SSD+HDC) and two lithogenic diets (LD5, LD10). ADC decreased significantly in LD10 (2.15 ± 0.07 × 10⁻³ mm²s⁻¹) and SSD+HDC (2.03 ± 0.04) compared to RC (2.40 ± 0.05) but not in the most lithogenic LD5 diet (2.33 ± 0.06). No direct relationship was found between bile viscosity and gallstone incidence; however, viscosity seems to be related to lipid contents of diets. Magn Reson Med 43:854–859, 2000. © 2000 Wiley-Liss, Inc.