3.0T intravoxel incoherent motion magnetic resonance imaging evaluation for the hepatic warm-ischemia injury in a rabbit model

Abstract

Objective To investigate the feasibility and diagnostic efficacy of 3.0T intravoxel incoherent motion (IVIM) magnetic resonance imaging (MRI) in the evaluation of hepatic warm ischemia-reperfusion injury (WIRI) in a rabbit model. Methods Fifty healthy, adult, male New Zealand white rabbits were randomly divided into sham-operation group (n=10) and four test groups (each n=10), which depended on different warm ischemia time (ie, 10, 20, 30, and 40 min group). Hepatic WIRI was induced by occluding hepatic inflow for different minute and reperfusion for 6 hours. Traditional MRI and IVIM were performed on a 3.0T clinical magnetic resonance (MR) scanner, four diffusion parameters, that is apparent diffusion coefficient (ADC), true diffusion (Dslow), pseudodiffusion (Dfast) and perfusion fraction (PF), were calculated from IVIM image. Rabbits were sacrificed for biochemical and histomorphological analysis after MR scanning, which including alanine transaminase (ALT), aspartate transaminase (AST), lactate dehydrogenase (LDH) of serum, and malondialdehyde (MDA), superoxide dismutase (SOD) and myeloperoxidase (MPO) of liver tissue. Statistical analysis was performed using one-way analysis of variance (ANOVA) or non-parametric test for multiple group comparisons of the IVIM parameters and biochemical parameters. The Pearson’s or Spearman’s correlation coefficient was calculated to assess the correlations between IVIM parameters and biochemical parameters. Receiver operating characteristic (ROC) curves were used to determine the diagnostic accuracy of IVIM parameters for predicting the hepatic WIRI. Results Compared with the sham group, the hepatic ADC, Dslow, Dfast, and PF were reduced in the test groups. Meanwhile, the values of IVIM parameters gradually decreased as prolonged warm ischemia time (ADC was 1.36±0.15, 1.28±0.07, 1.10±0.13, 1.10±0.15 and 0.98±0.18, Dslow was 1.29±0.14, 1.24±0.07, 1.08±0.11, 1.03±0.18 and 0.94±0.15, Dfast was 31.33±6.44, 25.53±2.10, 24.90±1.84, 23.00±1.59 and 23.76±1.41, PF was 30.44±2.80, 26.26±4.41, 24.50±2.24, 19.97±3.39 and 17.42±3.25, respectively) (P=0.005). IVIM parameters corresponded well with biochemical parameters (P=0.005). The area under curve (AUC) of ADC, Dslow, Dfast, and PF was 0.876, 0.824, 0.897 and 0.937, respectively. Histopathological analysis showed hepatocyte edema, inflammatory cell infiltration, sinusoids and central vein congestion, and different levels of fibrous tissue proliferation in the test groups. Conclusion 3.0T IVIM imaging is a noninvasive and quantitative technique in assessing the hepatic WIRI in a rabbit model, which implies its further application for dynamic monitoring of hepatic WIRI, and preclinical assessment of new pharmaceutics. Key words: Hepatic warm ischemia-reperfusion injury; Diffusion weighted imaging; Intravoxel incoherent motion; Magnetic resonance imaging