Fatty liver regeneration after partial hepatectomy: an experimental study based on intravoxel incoherent motion and T2* mapping MRI.

Objectives: To explore the feasibility of assessing liver regeneration (LR) after partial hepatectomy (PH) in a rat model of metabolic dysfunction-associated fatty liver (MAFL) using intravoxel incoherent motion (IVIM) and T2^* mapping.

Animal model: Eighty Sprague-Dawley rats with MAFLD were randomly assigned to a longitudinal MRI group and pathology group. The MRI group (n = 10) included hepatectomy (MRph, n = 5) and control (MRctrl, n = 5) subgroups, which underwent serials MRI scans. The pathology group (n = 70) included hepatectomy (PAph, n = 35) and control (PActrl, n = 35) subgroups, which underwent MRI scans at baseline, days 1, 2, 3, 5, 7, and 14 (five rats per group), followed with histopathological analysis. Correlations between MRI parameters, liver function indicators (ALT, AST, TBIL), and histopathology (Ki-67, hepatocyte hypertrophy rate [ΔH], liver volume [LV]) were analyzed.

Results: In the MRph group, D and T2^* values increased and then decreased post-PH, while D^* and PF values decreased and then increased, with all parameters trending toward baseline. The Ki-67 index, hepatocyte size, ΔH, and liver function indicators initially increased, and then gradually decreased. D^* was significantly negatively correlated with the Ki-67, hepatocyte size, ΔH, ALT, AST, TBIL, and LV (|r|= 0.53-0.83; all P < 0.05).

Conclusions: IVIM and T2^* mapping enabled non-invasive monitoring of LR in MAFL rats. IVIM-derived liver D^* correlated with liver function and pathology, highlighting its potential as a novel LR marker.