Utility of diffusion-weighted imaging in the evaluation of liver fibrosis.

OBJECTIVES: To evaluate the usefulness of diffusion- weighted MRI (DWI) in the detection and staging of liver fibrosis and inflammation. METHODS: DWI was performed with b-factors of 0, 500 and 1000 s/mm². ADC values were obtained by placing circular regions of interest in four segments of the liver. Differences between the study (n = 34) and control groups' (n = 25) ADC values were examined. Further, this study investigated if and how ADC values were related to fibrosis stages and histological activity index (HAI) scores. RESULTS: The mean ADC value of the liver was smaller in the study group compared with the control group (P < 0.001). Spearman rho correlation analyses showed lower ADC values were associated with higher fibrosis and HAI scores (P < 0.01). There were statistically significant differences in liver ADC values between each combination of fibrosis stages (e.g. stages 0 and 1, 0 and 2) except for stages 1 and 2. CONCLUSIONS: ADC values prove to be a valuable technique for the diagnosis of liver fibrosis and inflammation. They can also be useful in fibrosis staging, particularly in distinguishing later stages of fibrosis from intermediate and early stages. KEY POINTS: Diffusion Weighted MRI is a promising technique for diagnosis of liver fibrosis. Apparent Diffusion Coefficients provide valuable information for staging of liver fibrosis. DWI may offer alternative to biopsy for assessing liver fibrosis.