Utility of diffusion-weighted MRI for assessing liver fibrosis in patients with chronic active hepatitis.

PURPOSE We evaluated the utility of quantitative diffusion-weighted magnetic resonance imaging (DW-MRI) for assessing both the relationship between the degree of fibrosis and the histological activity index (HAI) in chronic hepatitis (CH) cases and attempted to determine whether the apparent diffusion coefficient value (ADC) could be used as a reference for the degree of fibrosis detected by histology. MATERIALS AND METHODS The study population consisted of 55 CH patients (Group I) and a control group of 30 volunteers (Group II). Group I consisted of 31 CH-B (CHB), 18 CH-C (CHC) and 6 non-alcoholic steatohepatitis patients. DW-MRI of the liver with b values of 0, 500 and 1000 s/mm(2) was performed, and liver biopsies of the patients were obtained two weeks later. The ADC value, degree of liver fibrosis and HAI were compared within Group I, and the ADC values of both groups were compared with each other. RESULTS The ADC was lower in Group I than in Group II (P < 0.05). The ADC of the left lobe lateral (LL) (P < 0.05), left lobe medial (LM) and right lobe anterior (RA) segments (P < 0.01) in Group I were lower than those of Group II. There was no relationship between HAI and the ADC of LL, LM, RA and right lobe posterior (RP) segments in Group I. Additionally, there was no correlation between fibrosis scores and ADC in Group I, whereas there was a negative correlation between fibrosis scores and ADC values of the LL (28.3%) and RP (29.5%). CONCLUSION CH patients had lower ADC values. There was no correlation between ADC values and fibrosis stages or ADC and HAI values. Quantitative DW-MRI was not useful in determining the degree of fibrosis in liver tissue.