Comparison of magnetic resonance elastography and diffusion-weighted imaging for staging hepatic fibrosis

Diffusion tensor imaging quantifying the severity of chronic hepatitis in rats

BACKGROUND

Diffusion tensor imaging (DTI) is mainly used for detecting white matter fiber in the brain. DTI was applied to assess fiber in liver disorders in previous studies. However, the data obtained have been insufficient in determining if DTI can be used to exactly stage chronic hepatitis. This study assessed the value of DTI for staging of liver fibrosis (F), necroinflammatory activity (A) and steatosis (S) with chronic hepatitis in rats.

METHODS

Seventy male Sprague-Dawley rats were divided into a control group(n = 10) and an experimental group(n = 60). The rat models of chronic hepatitis were established by abdominal subcutaneous injections of 40% CCl₄. All of the rats underwent 3.0 T MRI. Regions of interest (ROIs) were subjected to DTI to estimate the MR parameters (rADC value and FA value). Histopathology was used as the reference standard. Multiple linear regression was used to analyze the associations between the MR parameters and pathology. The differences in the MR parameters among the pathological stages were evaluated by MANOVA or ANOVA. The LSD test was used to test for differences between each pair of groups. ROC analysis was also performed.

RESULTS

The count of each pathology was as follows: F0(n = 15), F1(n = 11), F2(n = 6), F3(n = 9), F4(n = 6); A0(n = 8), A1(n = 16), A2(n = 16), A3(n = 7); S0(n = 10), S1(n = 7), S2(n = 3), S3(n = 11), S4(n = 16). The rADC value had a negative correlation with liver fibrosis (r = - 0.392, P = 0.008) and inflammation (r = - 0.359, P = 0.015). The FA value had a positive correlation with fibrosis (r = 0.409, P = 0.005). Significant differences were found in the FA values between F4 and F0 ~ F3 (P = 0.03), while no significant differences among F0 ~ F3 were found (P > 0.05). The AUC of the FA value differentiating F4 from F0 ~ F3 was 0.909 (p < 0.001) with an 83.3% sensitivity and an 85.4% specificity when the FA value was at the cut-off of 588.089 (× 10^- 6 mm²/s).

CONCLUSION

The FA value for DTI can distinguish early cirrhosis from normal, mild and moderate liver fibrosis, but the rADC value lacked the ability to differentiate among the fibrotic grades. Both the FA and rADC values were unable to discriminate the stages of necroinflammatory activity and steatosis.

Hepatoprotective effects and mechanisms of Ixeris denticulate water extract on liver cirrhosis in experimental rat

BACKGROUND

To explore the protective effect and mechanisms of Ixeris denticulate water extract (IDWE) in the development of liver cirrhosis in experimental rat.

METHODS

Sixty rats were randomly divided into five groups: control group, model group and IDWE (2, 4 and 8 g/kg) treatment groups. Alanine transferase (ALT), aspartate transaminase (AST), albumin (ALB), tumor necrosis factor-alpha (TNF-α), Interleukin (IL)-6 and IL-8 in serum and superoxide dismutase (SOD), malondialdehyde (MDA) in liver tissue were evaluated, respectively. The liver index, liver morphology and liver histopathological analysis were detected as a supportive data. The liver protein expression of Bcl-2 and Bax were assessed by western blot, and NF-κB p65 protein expression was determined by immunohistochemistry analysis.

RESULTS

The result showed that a significantly decrease in the levels of serum AST, ALT and serum inflammatory factors TNF-α, IL-6 and IL-8 in IDWE-treated rats. The levels of serum ALB and SOD in liver tissue were markedly increased after IDWE treated, compared with model rats. Furthermore, IDWE-treated group also exhibited a down-regulated protein expression of NF-κB p65 and Bax, up-regulated Bcl-2 protein expression.

CONCLUSIONS

IDWE could effectively alleviate the course of liver cirrhosis in rat model, which may be a potent hepatoprotective agent in clinical therapy in the future.

Hepatoprotective effects of Cassia semen ethanol extract on non-alcoholic fatty liver disease in experimental rat

CONTEXT

Cassia semen (Cs), a seed of Cassia obtusifolia L. (Leguminosae), is a popular functional beverage. Previous studies reported that Cs displayed antioxidant, antifungal and strong liver protective effects.

OBJECTIVE

This study evaluates the hepatoprotective effects of Cs on non-alcoholic fatty liver disease (NAFLD).

MATERIALS AND METHODS

Seventy-two male Wistar rats raised with high-fat diet (HFD) were randomly allotted into model, metformin (0.2 g/kg) and Cs (0.5, 1, and 2 g/kg)-treated groups. Another 12 rats were raised with normal feed as control group; all the rats were orally administrated with drugs and vehicle for 6 weeks. Alanine transferase (ALT), aspartate transaminase (AST), triglycerides (TG), total cholesterol (TC), malondialdehyde (MDA), superoxide dismutase (SOD), glutathione (GSH), tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-8 and low density lipoprotein receptor (LDL-R) mRNA levels were measured at the end of the experiment.

RESULTS

Twelve weeks of HFD administration significantly increased the levels of AST, ALT, TG, TC, TNF-α, IL-6, IL-8 and MDA, decreased SOD (199.42 vs. 137.70 U/mg protein) and GSH (9.76 vs. 4.55 mg/g protein) contents, compared to control group. Cs administration group significantly decreased the elevated biomarkers with the ED₅₀ = 1.2 g/kg for NAFLD rats. Cs treatment also prevents the decreased expression of LDL-R mRNA, and improved the histopathological changes compared to model group.

CONCLUSIONS

The hepatoprotective effect of Cs on NAFLD may possibly be due to its antioxidant effect. Cs may become a potent hepatoprotective agent in clinical therapy in the future.

Magnetic Resonance Diffusion Kurtosis Imaging for Evaluating Stage of Liver Fibrosis in a Rabbit Model

RATIONALE AND OBJECTIVES

As an extension of the conventional diffusion weighted imaging, diffusion kurtosis imaging (DKI) is based on the non-Gaussian diffusion model that can inherently account for restricted water diffusion within the complex microstructure of most tissues. This study aimed to investigate association of liver DKI derived parameter with stage of liver fibrosis.

MATERIALS AND METHODS

Fifty-six healthy New Zealand white rabbits were enrolled into this study, among which 48 rabbits were randomly given carbon tetrachloride to model liver fibrosis, and 8 rabbits treated with normal saline served as control subjects. All rabbits underwent liver DKI followed by biopsy to stage fibrosis (stages F0-F4) on 6th, 8th, 10th, and 12th weekends after initiation of modeling fibrosis. Mean kurtosis (MK), fractional anisotropy (FA), and mean diffusion (MD) were derived from DKI data. Statistical analysis was to evaluate association of DKI derived parameter with stage of fibrosis.

RESULTS

FA (r = 0.512) and MK (r = 0.567) increased, and MD (r = -0.574) decreased with increasing stage of fibrosis from F0 to F4 (all p values < 0.05). Significant differences were found in all parameters between F0 and F3 or F4, F1 and F4, F0 and F1-4, and F0-1 and F2-4 (all p values < 0.05). FA and MD could distinguish between F0 from F2, MD, and MK could distinguish F1 from F3, F0-2 from F3-4, and F1-2 from F3-4, and MK and FA could distinguish F2 from F4, and F0-3 from F4 (all p values < 0.05). According to receiver operating characteristic analysis, MK could best predict stage ≥F1, ≥F2, ≥F3, and F4, and discriminate F1-2 from F3-4 with areas under receiver operating characteristic curve of 0.766-0.930.

CONCLUSION

DKI derived parameters can help stage fibrosis.

Magnetic resonance elastography of liver and spleen: Methods and applications

The viscoelastic properties of the liver and spleen can be assessed with magnetic resonance elastography (MRE). Several actuators, MRI acquisition sequences and reconstruction algorithms have been proposed for this purpose. Reproducible results are obtained, especially when the examination is performed in standard conditions with the patient fasting. Accurate staging of liver fibrosis can be obtained by measuring liver stiffness or elasticity with MRE. Moreover, emerging evidence shows that assessing the tissue viscous parameters with MRE is useful for characterizing liver inflammation, non-alcoholic steatohepatitis, hepatic congestion, portal hypertension, and hepatic tumors. Further advances such as multifrequency acquisitions and compression-sensitive MRE may provide novel quantitative markers of hepatic and splenic mechanical properties that may improve the diagnosis of hepatic and splenic diseases.

Signal Transducer and Activator of Transcription 3 for the Differentiation of Hepatocellular Carcinoma from Cirrhosis

Background:

Overexpression and constitutive activation of signal transducer and activator of transcription (STAT) 3 have been suggested in the tumorigenesis of many human cancers, including multiple carcinomas, melanoma, and lymphoma. The diagnosis of hepatocellular carcinoma (HCC) in lobectomy specimens is usually straightforward, but distinguishing cirrhosis from well-differentiated HCC can be challenging in core biopsies. Our aims were to investigate the expression level of STAT3 and phosphorylated STAT3 (pSTAT3) in HCC and cirrhosis, and the application of STAT3 in the differential diagnosis of HCC and cirrhosis.

Methods:

Sixty cases were divided into three groups: patients with HCC only (Group 1), HCC and cirrhosis (Group 2), and cirrhosis only (Group 3). Formalin-fixed and paraffin-embedded tissue sections were stained immunohistochemically for STAT3, pSTAT3, and CD163. The values obtained from the tissue sections of each group were compared in statistical analysis.

Results:

STAT3 showed a high level in HCC and was a significant marker for differentiating HCC from cirrhosis (P < 0.0001). The odds ratio between HCC and cirrhosis increased 34.4 times when the intensity of STAT3 increased by 1 level. Spearman's correlation and Chi-square tests also demonstrated that expression level of STAT3 did not correlate with age, gender, or the presence of a cirrhotic background.

Conclusions:

STAT3 staining differs significantly in HCC and cirrhosis. The findings reinforce the role of STAT3 in the tumorigenesis of HCC and provide a useful marker to differentiate HCC from cirrhosis in challenging liver biopsies.

Magnetic Resonance Elastography and Diffusion Weighted Imaging in the Evaluation of Hepatic Fibrosis in Chronic Hepatitis B

Background/Aims

Comparison of the accuracy of magnetic resonance elastography (MRE) and diffusion weighted imaging (DWI) for the diagnosis of liver fibrosis in patients with chronic hepatitis B (CHB).

Methods

In this retrospective analysis, we investigated 63 patients with CHB and liver fibrosis. DWI was performed with both breath-hold (DWI-BH) and free-breathing (DWI-FB) sequences (b=0, 500). The mean liver stiffness and apparent diffusion coefficient (ADC) were calculated by drawing regions of interest maps. Fibrosis staging according to the METAVIR system was independently performed by an experienced pathologist. A receiver operating curve (ROC) analysis was conducted to determine the accuracy of MRE, DWI-BH and DWI-FB in the detection and stratification of liver fibrosis. The performance of the detection of significant fibrosis (≥F2), advanced fibrosis (≥F3), and cirrhosis (F4) was also evaluated by comparing areas under the ROC.

Results

There was a moderate and significantly negative correlation between the ADC values and liver stiffness. The accuracies for the detection of ≥F2/≥F3/F4 stage fibrosis with DWI-FB, DWI-BH and MRE were 0.84/0.76/0.72, 0.72/0.83/0.79 and 0.99/0.99/0.98, respectively. The performance of MRE was significantly better than DWI-FB and DWI-BH. There were no significant differences between the performance of DWI-FB and DWI-BH.

Conclusions

MRE is more accurate than DWI for the detection and stratification of liver fibrosis in CHB.

Prediction of liver cirrhosis, using diagnostic imaging tools

Early diagnosis of liver cirrhosis is important. Ultrasound-guided liver biopsy is the gold standard for diagnosis of liver cirrhosis. However, its invasiveness and sampling bias limit the applicability of the method. Basic imaging for the diagnosis of liver cirrhosis has developed over the last few decades, enabling early detection of morphological changes of the liver by ultrasonography (US), computed tomography, and magnetic resonance imaging (MRI). They are also accurate diagnostic methods for advanced liver cirrhosis, for which early diagnosis is difficult. There are a number of ways to compensate for this difficulty, including texture analysis to more closely identify the homogeneity of hepatic parenchyma, elastography to measure the stiffness and elasticity of the liver, and perfusion studies to determine the blood flow volume, transit time, and velocity. Amongst these methods, elastography using US and MRI was found to be slightly easier, faster, and able to provide an accurate diagnosis. Early diagnosis of liver cirrhosis using MRI or US elastography is therefore a realistic alternative, but further research is still needed.