Liver Fibrosis Assessment with Diffusion-Weighted Imaging: Value of Liver Apparent Diffusion Coefficient Normalization Using the Spleen as a Reference Organ

Liver fibrosis staging is of great clinical importance because it is used to assess the severity of the underlying chronic liver disease. Among various imaging-based methods, apparent diffusion coefficient (ADC) measurement using diffusion-weighted imaging (DWI) has the potential to be used as an imaging biomarker for liver fibrosis assessment. In this study, we investigated the usefulness of liver ADC normalization using the spleen as a reference organ in liver fibrosis staging with 66 patients who underwent liver magnetic resonance imaging (MRI), transient elastography (TE), and surgical resection of a hepatic mass. ADC values of the liver (ADC(liver)) and spleen were analyzed, and the spleen was used for ADC(liver) normalization (nADC(liver)). ADC(liver) showed a weak negative correlation with TE (r = −0.246; p = 0.047) and fibrosis stage (r = −0.269; p = 0.029), while n ADC(liver) showed a moderate negative correlation with TE (r = −0.504; p < 0.001) and fibrosis stage (r = −0.579; p < 0.001). AUC values for nADC(liver) (0.777–0.875) were higher than those for ADC(liver) for each stage of fibrosis (0.596–0.713, p = 0.037–0.157). AUC values for TE (0.726–0.884) and nADC(liver) were not statistically different. In conclusion, normalized liver ADC can be useful in diagnosing liver fibrosis stage in patients with variable DWI acquisitions.