Comparison and optimization of b value combinations for diffusion-weighted imaging in discriminating hepatic fibrosis.

Abstract

Diffusion-weighted imaging (DWI) has shown potential in characterizing hepatic fibrosis. However, there are no widely accepted apparent diffusioncoefficient (ADC) values for the b value combination. This study aims to determine the optimal high and low b values of DWI to assess hepatic fibrosis in patients with chronic liver disease. The prospective study included 81 patients with chronic liver disease and 21 healthy volunteers who underwent DWI, Magnetic resonance elastography (MRE), and liver biopsy. The ADC was calculated by twenty combinations of nine b values (0, 50, 100, 150, 200, 800, 1000, 1200, and 1500s/mm2). All ADC values of the healthy volunteers were significantly higher than those of the hepatic fibrosis group (all P < 0.01). With the progression of hepatic fibrosis, ADC values significantly decreased in b value combinations (100 and 1000s/mm2, 150 and 1200s/mm2, 200 and 800s/mm2, and 200 and 1000s/mm2). ADC values derived from b values of both200 and800s/mm2and200 and1000s/mm2were found to be more discriminative for differentiating the stages of hepatic fibrosis. An excellent correlation was between the ADC200-1000 value and MRE shear stiffness (r = -0.750, P < 0.001). DWI offers an alternative to MRE as a useful imaging marker for detecting and staging hepatic fibrosis. Clinically, ADC values for b values ranging from 200-800s/mm2to 200-1000s/mm2 are recommended for the assessment of hepatic fibrosis.