Diffusion-Weighted MRI for Quantification of Liver Fibrosis: Preliminary Experience

Abstract

OBJECTIVE. The purpose of this study was to evaluate our preliminary experience using diffusion-weighted MRI for quantification of liver fibrosis. SUBJECTS AND METHODS. Diffusion-weighted MRI with single-shot echo-planar technique at b values of 50, 300, 500, 700, and 1,000 s/mm² was prospectively performed on 23 patients with chronic hepatitis and on seven healthy volunteers. The apparent diffusion coefficient (ADC) was measured in four locations in the liver. Liver biopsy results (n = 19) were retrospectively reviewed by two hepatopathologists in consensus to determine stage of fibrosis and grade of inflammation. A Mann-Whitney test was used to compare the ADCs between patients classified with respect to having stage 2 or greater versus stage 1 or less fibrosis and stage 3 or greater versus stage or less 2 fibrosis. Receiver operating characteristics analysis was used to assess the performance of ADC in prediction of the presence of stage 2 or greater and stage 3 or greater fibrosis. RESULTS. Using a b value of 500 s/mm² and all combined b values, we found significantly lower hepatic ADCs in stage 2 or greater versus stage 1 or less fibrosis and stage 3 or greater versus stage 2 or less fibrosis. The mean ADCs (× 10^–3 mm²/s) with all b values were 1.47 ± 0.11 (SD) versus 1.65 ± 0.10 for stage 2 or greater versus stage 1 or less fibrosis (p < 0.001) and 1.44 ± 0.07 versus 1.66 ± 0.10 for stage 3 or greater versus stage 2 or less fibrosis (p –3 mm²/s or less). CONCLUSION. Diffusion-weighted MRI can be used for prediction of the presence of moderate and advanced liver fibrosis.