Diffusion analysis with triexponential function in liver cirrhosis

Abstract

To acquire more detailed information noninvasively through on diffusion and perfusion in normal and cirrhotic livers, we analyzed three diffusion components using triexponential function. Thirty-nine subjects (10 with noncirrhotic liver, 29 with cirrhosis) were assessed using diffusion-weighted magnetic resonance imaging (DWI) with multiple b-values. We derived perfusion-related diffusion, fast free diffusion, and slow restricted diffusion coefficients (Dp , Df , Ds ) and fractions (Fp , Ff , Fs ) calculated from triexponential function using DWI data. Moreover, the triexponential analysis was compared with biexponential and monoexponential analyses. All derived diffusion coefficients were correlated with relative enhancement ratio (RER) using dynamic contrast-enhanced MRI. In triexponential analysis, Fp , Dp , and Ds were significantly reduced in cirrhosis, whereas Ff was significantly increased in cirrhosis. There was no correlation between each diffusion coefficient obtained with the triexponential analysis in both groups, i.e., Dp , Df , and Ds , did not necessarily provide the same kind of information, but there was a positive correlation between each diffusion coefficient with the biexponential analysis in cirrhosis. A positive correlation was found between Dp and RER in the portal phase. Triexponential analysis makes it possible to noninvasively obtain more detailed tissue diffusion and perfusion information and to assist in the diagnosis of liver cirrhosis.