Metabolites Alterations and Liver Injury in Hepatic Encephalopathy Models Evaluated by Use of 7T-MRI

Abstract

This study is to observe a thioacetamide (TAA) administered Hepatic encephalopathy (HE) model rats at three and ten days after TAA administration using liver MRI and brain MR Spectroscopy (MRS) by use of 7T-MRI. Forty-two Wistar rats (control group, n = 14) were intraperitoneally administered at 300 mg/kg (low-dose group, n = 14) or 400 mg/kg (high-dose group, n = 14) doses of TAA for induced of HE. At three days after TAA administration, glutamine (Gln) measured by MRS in high-dose and low-dose TAA groups showed significant increases in comparison to those of the control group (p < 0.05). Other metabolites measured by MRS showed no significant changes. Liver T1ρ and T2 relaxation times significantly increased three days after TAA injection compared to pre-injection. There was a correlation between Gln levels in the brain and the relaxation time of the liver. Furthermore, Gln levels and relaxation time changed depending on the TAA dose. The Gln concentration in the brain increased with the deterioration of liver function, as inferred from the prolonged relaxation time of the liver. The prolonged relaxation time of the liver corresponded with the level of Gln in the brain. Gln concentration for the alterations of brain metabolites and T1ρ relaxation time for the assessment of liver damage are useful markers for inter-organ association analysis in the HE model.

Preclinical magnetic resonance imaging and spectroscopy in the fields of radiological technology, medical physics, and radiology

“…In preclinical small-bore high filed MRI, diffusion tensor imaging (DTI) [ 45 ], magnetic resonance spectroscopy (MRS) [ 30 , 46 ], magnetic resonance angiography (MRA) [ 47 ], arterial spin labeling (ASL) [ 48 ], susceptibility-weighted imaging (SWI) [ 49 ], and other imaging techniques that use these sequences are available. ASL, SWI, chemical exchange saturation transfer imaging (CEST) [ 23 , 29 , 31 , 50 ], Q-space imaging (QSI) [ 51 ], and relaxation time measurements of T1-, T2-, and T1rho-mapping [ 27 ] are available and can be used for most imaging methods applied in clinical practice.…”

“…Arihara et al [ 27 ] and Saito et al [ 30 ] measured the relaxation times such as T1rho and T2 values the liver of acute liver inflammation model administered carbon tetrachloride (CCl4) or a thioacetamide (TAA) after dispensed, and they compared and examined whether each relaxation time can be used for detect acute liver inflammation. The T1rho value changed significantly compared to the T2 value, and a continuous change was observed even after 6 days CCl4 administration.…”