Histogram analyses of diffusion kurtosis indices and apparent diffusion coefficient in assessing liver regeneration after ALPPS and a comparative study with portal vein ligation.

PURPOSE: To investigate the value of diffusion kurtosis imaging (DKI) histogram analysis in assessing liver regeneration and the microstructure basis after associating liver partition and portal vein ligation for staged hepatectomy (ALPPS), in comparison with portal vein ligation (PVL). MATERIALS AND METHODS: Thirty rats were divided into the ALPPS, PVL, and control groups. Histograms of DKI using a 3T magnetic resonance imaging (MRI) scanner were performed for corrected apparent diffusion (D), kurtosis (K), and apparent diffusion coefficient (ADC). Mean, median, skewness, kurtosis, and the percentiles (5th , 25th , 50th , 75th , and 95th ) were generated and compared, and radiologic-pathologic correlations were evaluated. RESULTS: There were more significant volume increases of the right median lobe after ALPPS than PVL (P = 0.0304/0.0017). The ALPPS group had larger hepatocyte size (P = 0.009/0.000), higher Ki-67 and hepatocyte growth factor expression (P = 0.001-0.036) compared with both PVL and control groups. Mean, median, 5th , 25th , 50th , 75th percentiles of D map in ALPPS were lower than the control group (P = 0.001-0.022). Skewness and 75th , 95th percentiles of K map in ALPPS were higher than the PVL group (P = 0.011-0.042). No differences existed in the ADC map between groups (P = 0.073-0.291). Mean, median, 5th , 25th , 50th percentiles of D map, and 5th percentile of K map showed significant correlations with hepatocyte size (r = -0.582 to -0.426); no significant correlations were found in ADC parameters (P = 0.460-0.934). CONCLUSION: ALPPS induced true accelerated liver hypertrophy, superior to that seen with PVL. Histogram analysis of diffusion kurtosis indices may provide added values in evaluating liver regeneration and the intrinsic microstructure basis after ALPPS in comparison with the standard monoexponential ADC. LEVEL OF EVIDENCE: 3 Technical Efficacy Stage: Stage 2 J. Magn. Reson. Imaging 2018;47:729-736.