E4945. Evaluation of Hepatic Metabolic Change for Monitoring the Progression of Hepatitis to Liver Fibrosis Using Hyperpolarized 13C MRI
  1. Sang Soo Shin; Chonnam National University Medical School
  2. Chung Man Moon; Chonnam National University Medical School
This study aimed to investigate the feasibility of in vivo hyperpolarized 13C MRI to assess hepatic metabolic changes for monitoring the progression of hepatitis B virus (HBV)-related hepatitis to liver fibrosis from normal liver.

Materials and Methods:
Hepatitis in the mice (n = 8) was induced by hydrodynamic injection of 25 µg of HBV 1.2 plasmid via tail vein, and liver fibrosis in the mice (n = 8) was induced by the weight-adapted administration of thioacetamide with ethanol. Normal control mice (n = 8) were injected with phosphate buffer solution. Hyperpolarized 13C MRI was performed on a 3-T clinical MRI scanner (Discovery MR750; GE Healthcare, Milwaukee, WI, USA) using a 1H/13C dual mouse coil (Rapid Biomedical, Würzburg, Germany). Four metabolites, including lactate, pyruvate-hydrate, alanine, and pyruvate, were measured from 13C MR spectra. To quantify the 13C label exchange reaction rates of lactate and alanine converted from pyruvate, the AUC ratios were calculated. After 13C MRI examination, blood chemistry, including the level of hepatitis B surface antigen (HBsAg), and histopathological analysis were performed. Data were compared among the groups using the Kruskal-Wallis one-way analysis of variance.

HBsAg was absent in the normal and fibrosis groups, and its presence was confirmed in the hepatitis group. HBV-infected mice showed advanced viral cytopathic changes, but no fibrosis was observed, as with normal control. In the fibrosis group, five and three mice were categorized as stage 1 and stage 2, respectively. The ratios of lactate/pyruvate and alanine/pyruvate in normal group were significantly lower than in both hepatitis and fibrosis groups (p < 0.05). Further, these ratios in fibrosis group were significantly higher than in the hepatitis group (p < 0.05). The 13C label exchange reaction rates of both lactate and alanine were significantly higher in hepatitis and fibrosis groups than in control group, and higher in fibrosis group than in hepatitis group (p < 0.05).

Hyperpolarized 13C MRI may play a role for differentiating among hepatitis, hepatic fibrosis, and normal liver through quantifying the levels of lactate and alanine.