Quantitative Evaluation of Nonalcoholic Fatty Liver in Rat by Material Decomposition Techniques using Rapid-switching Dual Energy CT.

RATIONALE AND OBJECTIVES: To evaluate the material decomposition (MD) techniques in rapid kVp switching dual-energy CT (rsDECT) for quantifying liver fat content in rats with nonalcoholic fatty liver. MATERIALS AND METHODS: Fifty male Sprague-Dawley (SD) rats were divided into study group (n=37) and control group (n = 13) and underwent rsDECT examination at different intervals. All the data analysis was performed using AW4.7 workstation. The fat contents under the traditional fat(water), fat(blood), and fat(muscle) material decomposition (MD) images and the fat volume fraction (FVF) from the liver fat maps generated using multi-material decomposition (MMD) technique were measured. The pathological grades (grade 0, 1, 2 and 3) of fatty liver were determined after euthanasia. The measurement differences among different grades and the correlation of measurements with different grades was analyzed using ANOVA and Spearman correlation, respectively. A receiver operating characteristics (ROC) curve was used to analyze the diagnostic efficacies of fat contents and FVF. RESULTS: There were statistically significant differences in FVF and fat contents under fat(water), fat(blood), fat(muscle) based MD images among different grades. These values correlated well with the pathological grades (R-value: 0.90, 0.75, 0.79, 0.80, all p <0.001), with FVF having the highest correlation. The area-under-the-curve in ROC of using FVF was the highest, with the cut-off value of 0.92 for sensitivity of 89.2% and specificity of 100%. CONCLUSION: The rsDECT MD techniques could quantitatively evaluate the fat content of fatty liver in rat, with the FVF from MMD having the highest correlation with pathological grades.

Noninvasive evaluation of esophageal varices in cirrhotic patients based on spleen hemodynamics: a dual-energy CT study.

OBJECTIVE: To evaluate noninvasively the severity of esophageal varices (EV) in cirrhotic patients using splenic hemodynamics obtained with dual-energy CT. METHODS: We retrospectively analyzed 72 cirrhotic patients with EV between December 2018 and June 2019. Patients were divided into three groups: mild (EV1), medium (EV2), or severe (EV3) EV groups based on severity of EV assessed by endoscopy. An additional control group included 20 patients with normal liver CT. All patients underwent contrast-enhanced dual-energy CT. The iodine weight in spleen (IW-S) was calculated as IW-S = IC-S (iodine concentration in spleen) × V-S (spleen volume). Differences between EV and control groups were analyzed using one-way analysis of variance with Welch's correction. Games-Howell test made further pairwise comparison. The diagnostic value of IW-S on high-risk EV (EV2, EV3, or EV1 with red color sign) was evaluated using the ROC curve. p < 0.05 indicated statistical significance. RESULTS: The overall difference of IW-S between the control and EV groups was statistically significant (p < 0.001). Patients with more severe EV had higher IW-S values. Pairwise comparisons showed that except for control vs. EV1 groups, the IW-S between any other two groups was significantly different (p < 0.05). With a cutoff value at 1087 mg, the AUC for using IW-S for the detection of high-risk EV was 0.87 (95% CI 0.77~0.94). Sensitivity and specificity were 84.9% and 84.2%, respectively. CONCLUSION: IW-S obtained with dual-energy CT can noninvasively predict EV severity. KEY POINTS: • A higher iodine weight in spleen (IW-S) was observed in case of severe esophageal varices. • Cirrhotic patients have significantly higher IW-S than normal-liver patients. • IW-S in dual-energy CT maybe used to evaluate the severity of EV.

Assessing Liver Hemodynamics in Children With Cholestatic Cirrhosis by Use of Dual-Energy Spectral CT.

OBJECTIVE. The purpose of this study was to evaluate the value of dual-energy CT (DECT) in assessing liver hemodynamics in children with cholestatic cirrhosis. MATERIALS AND METHODS. The cases of 60 children with cholestatic cirrhosis (study group) and 15 children with inherited metabolic diseases but normal liver function (control group) were retrospectively evaluated. Enhanced CT scans were obtained in spectral imaging mode. Iodine concentration (IC) of hepatic parenchyma in the arterial phase (ICA) and portal venous phase (ICP) was measured on iodine-water material decomposition images. The hepatic arterial iodine fraction (AIF) was calculated as: AIF = ICA / ICP. The ICA, ICP, and AIF of children in the control and study groups were analyzed by one-way ANOVA and post hoc test with Bonferroni correction. The radiation dose was recorded. RESULTS. There were differences in ICA and AIF between the control and study groups. The values in patients in the Child-Pugh class C group were the highest and those in the control group the lowest (p < 0.05). Statistically significant differences in ICP were not found (p > 0.05). Specifically, the multiple comparison results indicated that there were differences in both ICA and AIF in most of the groups (p < 0.05). The volume CT dose index value for all patients was the same at 10.14 mGy for each enhanced phase, and the total dose-length product varied between 402.68 and 679.18 mGy-cm. CONCLUSION. ICA and AIF obtained at dual-energy CT can be used as semiquantitative indicators to evaluate the liver hemodynamics of children with cholestatic cirrhosis.

Evaluation on Heterogeneity of Fatty Liver in Rats: A Multiparameter Quantitative Analysis by Dual Energy CT.

RATIONALE AND OBJECTIVES: To investigate the value of using rapid kVp switching dual energy computed tomography (rsDECT) for the multi-parameter analysis of the heterogeneity of fatty liver in rat. MATERIALS AND METHODS: Twenty-four male rats were randomly divided into experimental (n = 16) and control (n = 8) groups. Four rats in the experimental group and two in the control group were examined by rsDECT every 3 weeks starting from week 8. The liver fat contents (LFC) of the left and right liver lobes were measured on the fat(water)-based material decomposition images to calculate fat content and CT value of liver and spleen were measured on the 70keV monochromatic images to calculate the liver-to-spleen CT value ratio [(L/S)70 keV] and difference at 70keV[(L-S)70 keV], and the spectral curve slopes of the left and right liver lobes (Slope-L, Slope-R). Measurements were evaluated statistically. RESULTS: The statistical analysis showed that the (L/S)70 keV, (L-S)70 keV, Slope and LFC in the different fatty liver groups were all significantly different (p < 0.05). Pearson correlation analysis results showed that the rsDECT results of the left and right liver lobes correlated with the fat percentage from pathological analysis (p < 0.05), with the left liver lobe having better correlation. Paired t-tests showed that the fat percentage of the left liver lobe was significantly higher than that of the right one, while (L/S)70 keV, and (L-S)70 keV were significantly lower. Diagnostic analysis using ROC curve showed that the areas under the curves with parameters of the left liver lobe were also greater than those of the right liver lobe. CONCLUSION: rsDECT multi-parameter imaging could quantitatively evaluate the heterogeneity of fat deposition in the liver, providing valuable information for the accurate and effective assessment of the heterogeneity of fatty liver.

Targeted metabolomic study indicating glycyrrhizin's protection against acetaminophen-induced liver damage through reversing fatty acid metabolism.

The present study aimed to give a short report on a possible mechanism of glycyrrhizin to acetaminophen-induced liver toxicity. Seven-day intraperitoneal administration of glycyrrhizin (400 mg/kg/day) to 2- to 3-month-old male C57BL/6N mice (mean weight 27 g) significantly prevents acetaminophen-induced liver damage, as indicated by the activity of alanine transaminase and aspartate aminotransferase. Metabolomics analysis and principal component analysis (PCA) using ultra-fast liquid chromatography coupled to triple time-of-flight mass spectrometer were performed. PCA separated well the control, glycyrrhizin-treated, acetaminophen-treated, and glycyrrhizin+acetaminophen-treated groups. Long-chain acylcarnitines were listed as the top ions that contribute to this good separation, which include oleoylcarnitine, palmitoylcarnitine, palmitoleoylcarnitine, and myristoylcarnitine. The treatment of glycyrrhizin significantly reversed the increased levels of long-chain acylcarnitines induced by acetaminophen administration. In conclusion, this metabolomic study indicates a significant glycyrrhizin protection effect against acetaminophen-induced liver damage through reversing fatty acid metabolism.