OBJECTIVETo investigate the alteration of apparent diffusion coefficient (ADC) in diffusion-weighted MR imaging (MR-DWI) of liver fibrosis and its pathological basis in rabbits.

METHODSFive rabbits in the control group and 22 with experimental liver fibrosis induced by transperitoneal injection of carbon tetrachloride (CCl4) were examined with MR-DWI. Diffusion-weighted SE EPI sequence with a relatively high b factor (b=600 s/mm2) was used to measure the ADC. The mean values of ADC were compared among the rabbits in different stages of liver fibrosis and analyzed in relation to the pathological findings.

RESULTSThe mean ADC value decreased significantly with increased severity of liver fibrosis (P<0.05). Pathologically, the amount and extension of fibrotic matrix increased, and the hepatic necroinflammation worsened with the progression of the liver fibrosis.

CONCLUSIONThe ADC value decreases with the progression of liver fibrosis possibly as the result of water diffusion limitation due to increased fibrous tissue in the liver and abnormal water diffusion within the intracellular and extracellular spaces.