Evaluating Inflammation and Fibrosis Without Fat Influence in Metabolic Dysfunction-Associated Fatty Liver Disease: Pathological and Radiological Correlation in Rats

Motivation: In metabolic dysfunction-associated fatty liver disease (MAFLD), fat, fibrosis, and inflammation coexist during disease progression. Therefore, MRI parameters, including fat-corrected T1, are needed to reflect inflammation and fibrosis. Goal(s): To identify MRI images that accurately reflect inflammation and fibrosis, excluding fat. Approach: Rats were fed a choline-deficient, L-amino acid-defined high-fat diet to induce MAFLD. We quantitatively compared MRI parameters with histopathological measures of whole liver fat, fibrosis, ferritin, and inflammation. Results: Fat-corrected T1 values strongly correlated with fat, fibrosis, and inflammatory cells (CD45, CD68). Multiple linear regression revealed that fibrosis and inflammatory cells significantly affected fat-corrected T1 values, while fat did not. Impact: In metabolic dysfunction-associated fatty liver disease, fat-corrected T₁ values vary in response to the levels of inflammation and fibrosis rather than fat. Therefore, fat-corrected T₁ values may be useful in distinguishing simple fatty liver from fatty hepatitis or predicting of prognosis.