A comparison of 31P magnetic resonance spectroscopy and microbubble-enhanced ultrasound for characterizing hepatitis c-related liver disease

Evaluation of Rabbits Liver Fibrosis Using Gd-DTPA-BMA of Dynamic Contrast-Enhanced Magnetic Resonance Imaging

Objective

To evaluate the different pharmacokinetic parameters of the DCE-MRI method on diagnosing and staging of rabbits' liver fibrosis.

Methods

We had performed DCE-MRI for rabbits that had been divided into the experiment group and the control group. Then, rabbits' images were transferred to a work station to get three parameters such as K _trans, K _ep, and V _e, which had been measured to calculate. After data were analyzed, ROC analyses were performed to assess the diagnostic performance of K _trans, K _ep, and V _e to judge liver fibrosis.

Results

The distribution of the different liver fibrosis group was as follows: F1, n = 8; F2, n = 9; F3, n = 6; F4, n = 5. No fibrosis was deemed as F0, n = 6. K _ep is statistically significant (P < 0.05) for F0 and mild liver fibrosis stage, and the K _ep shows AUC of 0.814. Three parameters are statistically significant for F0 and advanced liver fibrosis stage (K _trans and K _ep, P < 0.01; V _e, P < 0.05), and the K _trans shows AUC of 0.924; the K _ep shows AUC of 0.909; the V _e shows AUC of 0.848; K _trans and K _ep are statistically significant for mild and advanced liver fibrosis stages (K _trans, P < 0.01; K _ep, P < 0.05), and the K _trans shows AUC of 0.840; the K _ep shows AUC of 0.765. Both K _trans and K _ep are negatively correlated with the liver fibrosis stage. V _e is positively correlated with the liver fibrosis stage.

Conclusion

K _trans is shown to be the best DCE parameter to distinguish the fibrotic liver from the normal liver and mild and advanced fibrosis. On the contrary, K _ep is moderate and V _e is worst. And K _ep is a good DCE parameter to differentiate mild fibrosis from the normal liver.

Diagnostic Accuracy of Hepatic Vein Arrival Time Performed with Contrast-Enhanced Ultrasonography for Cirrhosis: A Systematic Review and Meta-Analysis

Background/Aims

We identified reports in the literature regarding the diagnostic accuracy of hepatic vein arrival time (HVAT) measured by contrast-enhanced ultrasonography (CEUS) to assess hepatic fibrosis in cirrhosis.

Methods

The Ovid MEDLINE, Embase, and Cochrane databases were searched for all studies published up to 23 July 2015 that evaluated liver status using CEUS and liver biopsy (LB). The QUADAS-II (quality assessment of diagnostic accuracy studies-II) was applied to assess the internal validity of the diagnostic studies. Selected studies were subjected to a meta-analysis with MetaDisc 1.4 and RevMan 5.3.

Results

A total of 12 studies including 844 patients with chronic liver disease met our inclusion criteria. The overall summary sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio of the HVAT measured by CEUS for the detection of cirrhosis compared to LB were 0.83 (95% confidence interval [CI], 0.77 to 0.89), 0.75 (95% CI, 0.69 to 0.79), 3.45 (95% CI, 1.60 to 7.43), and 0.28 (95% CI, 0.10 to 0.74), respectively. The summary diagnostic odds ratio (random effects model) was 15.23 (95% CI, 3.07 to 75.47), the summary receiver operator characteristics area under the curve was 0.74 (standard error [SE]=0.14), and the index Q was 0.69 (SE=0.11).

Conclusions

Based on a systematic review, the measurement of HVAT by CEUS exhibited an increased accuracy and correlation for the detection of cirrhosis.

Hepatic gadoxetic acid uptake as a measure of diffuse liver disease: Where are we?

MRI has emerged as the most comprehensive noninvasive diagnostic tool for focal liver lesions and diffuse hepatobiliary disorders. The introduction of hepatobiliary contrast agents, most notably gadoxetic acid (GA), has expanded the role of MRI, particularly in the functional imaging of chronic liver diseases, such as nonalcoholic fatty liver disease (NAFLD). GA-enhanced MRI (GA-MRI) may help to distinguish between the two subgroups of NAFLD, simple steatosis and nonalcoholic steatohepatitis. Furthermore, GA-MRI can be used to stage fibrosis and cirrhosis, predict liver transplant graft survival, and preoperatively estimate the risk of liver failure should major resection be undertaken. The amount of GA uptake can be estimated, using static images, by the relative liver enhancement, hepatic uptake index, and relaxometry of T1-mapping during the hepatobiliary phase. On the contrary, the hepatic extraction fraction and liver perfusion can be measured on dynamic imaging. Importantly, there is currently no clear consensus as to which of these MR-derived parameters is the most suitable for assessing liver dysfunction. This review article aims to describe the current role of GA-enhanced MRI in quantifying liver function, primarily in diffuse hepatobiliary disorders.

LEVEL OF EVIDENCE

3 J. Magn. Reson. Imaging 2017;45:646-659.

[Functional MR imaging of the liver]

The diagnostics of diffuse liver disease traditionally rely on liver biopsies and histopathological analysis of tissue specimens. However, a liver biopsy is invasive and carries some non-negligible risks, especially for patients with decreased liver function and those requiring repeated follow-up examinations. Over the last decades, magnetic resonance imaging (MRI) has developed into a valuable tool for the non-invasive characterization of focal liver lesions and diseases of the bile ducts. Recently, several MRI methods have been developed and clinically evaluated that also allow the diagnostics and staging of diffuse liver diseases, e.g. non-alcoholic fatty liver disease, hepatitis, hepatic fibrosis, liver cirrhosis, hemochromatosis and hemosiderosis. The sequelae of diffuse liver diseases, such as a decreased liver functional reserve or portal hypertension, can also be detected and quantified by modern MRI methods. This article provides the reader with the basic principles of functional MRI of the liver and discusses the importance in a clinical context.

Imaging methods for evaluation of liver fibrosis

Liver fibrosis is a development stage of various chronic liver diseases. Since liver fibrosis is still a reversible process, the development of irreversible cirrhosis can be delayed or prevented if the patient is early diagnosed and receives timely and effective treatment. Therefore, how to accurately, effectively and easily evaluate the severity of liver fibrosis remains a clinical problem to be solved. Ultrasound, CT and MRI are common examinations for hepatic lesions. Imaging examinations can non-invasively and accurately evaluate the degree of liver fibrosis. With the development and application of new imaging technologies, flexible technology has been widely applied in the assessment of liver fibrosis. This article reviews the application of various imaging modalities, especially elastic technology, for assessment of hepatic fibrosis.

A non-invasive magnetic resonance imaging-based model predicts portal venous pressure

OBJECTIVE

To establish a non-invasive model for the assessment of portal venous pressure (PVP) based on the magnetic resonance (MR) parameters.

METHODS

In this prospective study, contrast-enhanced magnetic resonance imaging (MRI) scan was performed in 109 patients indicated for upper abdominal surgeries after their written consents were obtained, and intraoperative PVP measurements were completed in 92 patients. Altogether 17 patients were excluded for not undergoing surgery or unsuccessful catheterization. A linear model was constructed for estimating PVP levels in 56 patients and further validation was conducted in the other 36 patients.

RESULTS

The PVP levels were significantly correlated with MR parameters, including splenic volume (SV), splenic venous diameter (SVD), liver/splenic volume ratio, portal venous diameter, hepatic diameter, portal venous cross-sectional area, ascites, varices and arterial portal shunts. A linear model was established as follows: PVP (mmHg) = 2.529 + 1.572 × SVD (mm) + 0.231 × SV/body mass index (× 10(4) cm(5) /kg) + 3.44 × aspartate aminotransferase-to-platelet ratio index. This model showed excellent accuracy in the detection of portal hypertension, with the area under the receiver operating characteristic curve (AUROC) of 0.945 (95% CI 0.867-1.000), with the sensitivity and specificity of 91.7% and 93.7%, respectively. The agreement analysis revealed that the predictive value using this formula closely reflected the patients' actual PVP level. Moreover, the validation confirmed the accuracy of this model for the assessment of portal hypertension [AUROC 0.935 (95% CI 0.856-1.000)].

CONCLUSIONS

The MRI-based formula has great potential for detecting portal hypertension. As a non-invasive measurement, it may be clinically accepted for the replacement of invasive modalities after further refinement.

1H Magnetic Resonance Spectroscopy Predicts Hepatocellular Carcinoma in a Subset of Patients With Liver Cirrhosis: A Randomized Trial

The goal of this study was to investigate the utility of H magnetic resonance spectroscopy (H-MRS) to quantify the differences in liver metabolites. Magnetic resonance spectroscopy was used as a means of predicting the probability of developing hepatocellular carcinoma (HCC) in patients with liver cirrhosis secondary to chronic hepatitis B.This study included 20 healthy volunteers, 20 patients with liver cirrhosis secondary to chronic hepatitis B (cirrhosis group), and 20 patients with small HCC secondary to cirrhosis liver parenchyma (HCC group). All patients underwent routine MRI and H-MRS scanning. LCModel software was used to quantify Cho (Choline), Lip (lipid), and Cho/Lip in the 3 groups, and a one-way ANOVA was used to compare the differences in these metabolites between groups.Choline levels were significantly different between the control and HCC group and between the cirrhosis group and the HCC group (all P < 0.001). There was also a significant difference in Lip levels between the control and cirrhosis group and the control and HCC groups (all P < 0.001). There were also differences in Cho/Lip between the control and cirrhosis groups, the control and HCC groups, and the cirrhosis and HCC groups (all P < 0.001).H-MRS followed by the analysis with LCModel can be used to measure changes in hepatic metabolite levels in patients with liver cirrhosis secondary to chronic hepatitis B and HCC. Thus, H-MRS may be helpful in monitoring HCC and liver cirrhosis development.

The diagnostic efficacy of quantitative liver MR imaging with diffusion-weighted, SWI, and hepato-specific contrast-enhanced sequences in staging liver fibrosis--a multiparametric approach

PURPOSE

To assess the diagnostic efficacy of multiparametric MRI using quantitative measurements of the apparent diffusion coefficient (ADC) of the liver parenchyma on diffusion-weighted imaging (DWI), signal intensity (SI) on susceptibility-weighted imaging (SWI), and gadoxetic acid-enhanced T1-weighted imaging during the hepatobiliary phase for the staging of liver fibrosis.

MATERIALS AND METHODS

Seventy-seven patients underwent a 3T MRI examination, including DWI/SWI sequences and gadoxetic acid-enhanced T1-weighted MRI. Liver fibrosis according to liver biopsy was staged using the Metavir fibrosis score: F0 (n = 21, 27.3%); F1 (n = 7, 9.1%); F2 (n = 8, 10.4%); F3 (n = 12, 15.6%); and F4 (n = 29, 37.7%). SI of the liver was defined using region-of-interest measurements to calculate the ADC values, the relative enhancement (RE) in the hepatobiliary phase, and the liver-to-muscle ratio (LMR) measurements for SWI.

RESULTS

The values of RE, LMR, and ADC measurements were statistically significantly different among the five fibrosis stages (p < 0.004). Combining the three parameters in a multiparametric approach, the AUC for detecting F1 stage or greater (≥ F1) was 94%, for F2 or greater (≥F2) was 95%, for F3 or greater (≥F3) was 90%, and for stage F4 was 93%.

CONCLUSIONS

Multiparametric MRI is an efficient non-invasive diagnostic tool for the staging of liver fibrosis.

KEY POINTS

• Multiparametric MRI has high accuracy in predicting moderate or greater liver fibrosis. • Relative enhancement post- gadoxetic acid is an independent predictor of liver fibrosis. • Liver SWI signal intensity and ADC values enhance the diagnostic ability.

Susceptibility-weighted MR imaging in the grading of liver fibrosis: a feasibility study

PURPOSE

To assess the feasiblity of magnetic resonance (MR) susceptibility-weighted (SW) imaging as a tool to evaluate liver fibrosis grades in patients with chronic liver diseases (CLD) utilizing signal intensity (SI) measurements, with histopathologic findings as the reference standard.

MATERIALS AND METHODS

This retrospective study was approved by the local ethics committee. All subjects gave written informed consent. Eighty consecutive patients (mean age, 56.8 years), 60% of whom were male [n = 48] and 40% of whom were female [n = 32], with CLD due to various underlying causes and histopathologically proved liver fibrosis were included. Biopsies were evaluated for liver fibrosis and necroinflammatory activity (according to METAVIR scoring system), iron load, and steatosis. Two radiologists, blinded to the clinical data, assessed regions of interest in the liver and spinal muscle in consensus. Liver-to-muscle SI ratios were calculated and correlated to histopathologic findings and clinical data by using univariate and multivariate regression analysis.

RESULTS

Liver-to-muscle SI ratio decreased in parallel with the increasing grade of liver fibrosis and correlated strongly with liver fibrosis (r = -0.81, P < .0001) and moderately with necroinflammatory activity (r = -0.52, P < .0001) and iron load (r = -0.37, P = .0002) but did not correlate with steatosis (r = -0.18, P = .11). In multiple regression analysis, liver fibrosis and iron load independently influenced SW imaging measurements, explaining 69% of the variance of liver-to-muscle SI ratio (R(2) = 0.69, P < .001). Liver-to-muscle SI ratio performed well in grading liver fibrosis, with an area under the receiver operating characteristic curve of 0.92 for scores of F2 or higher and 0.93 for score of F4 (liver cirrhosis).

CONCLUSION

SW imaging is a feasible noninvasive tool to detect moderate and advanced liver fibrosis in CLD patients.