Evaluation of fibrosis and inflammation in diffuse liver diseases using intravoxel incoherent motion diffusion-weighted MR imaging

Purpose The purpose of the study was to evaluate the role of intravoxel incoherent motion (IVIM) diffusion model for the assessment of liver fibrosis and inflammation in diffuse liver disorders, also considering the presence of liver steatosis and iron deposits. Methods Seventy-four patients were included, with liver biopsy and a 3 Tesla abdominal magnetic resonance imaging examination, with an IVIM diffusion-weighted sequence (single-shot spin-echo echo-planar sequence, with gradient reversal fat suppression; 6 b -values: 0, 50, 200, 400, 600, and 800 s/mm 2 ). Histological evaluation comprised the Ishak modified scale, for grading inflammation and fibrosis, plus steatosis and iron loading classification. The liver apparent diffusion coefficient (ADC) and IVIM parameters ( D , D *, f ) were calculated from the IVIM images. The relationship between IVIM parameters and histopathological scores were evaluated by ANOVA and Spearman correlation tests. A test–retest experiment assessed reproducibility and repeatability in 10 healthy volunteers and 10 randomly selected patient studies. Results ADC and f values were lower with higher fibrosis stages ( p = 0.009, p = 0.006, respectively) and also with higher necro-inflammatory activity grades ( p = 0.02, p = 0.017, respectively). Considered together, only fibrosis presented a significant effect on ADC and f measurements ( p 0.05). A mild correlation was found between ADC and f with fibrosis ( R S = −0.32 and R S = −0.38; p