Transient elastography for the assessment of chronic liver disease: Ready for the clinic?

Assessment of Ultra-Early-Stage Liver Fibrosis in Human Non-Alcoholic Fatty Liver Disease by Second-Harmonic Generation Microscopy

Non-alcoholic fatty liver disease (NAFLD) is associated with the chronic progression of fibrosis. In general, the progression of liver fibrosis is determined by a histopathological assessment with a collagen-stained section; however, the ultra-early stage of liver fibrosis is challenging to identify because of the low sensitivity in the collagen-selective staining method. In the present study, we demonstrate the feasibility of second-harmonic generation (SHG) microscopy in the histopathological diagnosis of the liver of NAFLD patients for the quantitative assessment of the ultra-early stage of fibrosis. We investigated four representative NAFLD patients with early stages of fibrosis. SHG microscopy visualised well-matured fibrotic structures and early fibrosis diffusely involving liver tissues, whereas early fibrosis is challenging to be identified by conventional histopathological methods. Furthermore, the SHG emission directionality analysis revealed the maturation of each collagen fibre of each patient. As a result, SHG microscopy is feasible for assessing liver fibrosis on NAFLD patients, including the ultra-early stage of liver fibrosis that is difficult to diagnose by the conventional histopathological method. The assessment method of the ultra-early fibrosis by using SHG microscopy may serve as a crucial means for pathological, clinical, and prognostic diagnosis of NAFLD patients.

Establishing ultrasound based transient elastography cutoffs for different stages of hepatic fibrosis and cirrhosis in Egyptian chronic hepatitis C patients

BACKGROUND AND STUDY AIM

Transient elastography is widely used to assess fibrosis stage in chronic hepatitis C (CHC). We aimed to establish and validate different transient elastography cut-off values for significant fibrosis and cirrhosis in CHC genotype 4 patients.

PATIENTS AND METHODS

The data of 100 treatment-naive CHC patients (training set) and 652 patients (validation set) were analysed. The patients were subjected to routine pretreatment laboratory investigations, liver biopsy and histopathological staging of hepatic fibrosis according to the METAVIR scoring system. Transient elastography was performed before and in the same week as liver biopsy using FibroScan (Echosens, Paris, France). Transient elastography results were correlated to different stages of hepatic fibrosis in both the training and validation sets.

RESULTS

ROC curves were constructed. In the training set, the best transient elastography cut-off values for significant hepatic fibrosis (≥F2 METAVIR), advanced hepatic fibrosis (≥F3 METAVIR) and cirrhosis (F4 METAVIR) were 7.1, 9 and 12.2 kPa, with sensitivities of 87%, 87.5% and 90.9% and specificities of 100%, 99.9% and 99.9%, respectively. The application of these cut-offs in the validation set showed sensitivities of 85.5%, 82.8% and 92% and specificities of 86%, 89.4% and 99.01% for significant hepatic fibrosis, advanced hepatic fibrosis and cirrhosis, respectively.

CONCLUSION

Transient elastography performs well for significant hepatic fibrosis, advanced hepatic fibrosis and cirrhosis, with validated cut-offs of 7.1, 9 and 12.2 kPa, respectively, in genotype 4 CHC patients.

Magnetization-tagged MRI is a simple method for predicting liver fibrosis

Background/Aims:

To assess the usefulness of magnetization-tagged magnetic resonance imaging (MRI) in quantifying cardiac-induced liver motion and deformation in order to predict liver fibrosis.

Methods:

This retrospective study included 85 patients who underwent liver MRI including magnetization-tagged sequences from April 2010 to August 2010. Tagged images were acquired in three coronal and three sagittal planes encompassing both the liver and heart. A Gabor filter bank was used to measure the maximum value of displacement (MaxDisp) and the maximum and minimum values of principal strains (MaxP1 and MinP2, respectively). Patients were divided into three groups (no fibrosis, mild-to-moderate fibrosis, and significant fibrosis) based on their aspartate-aminotransferase-to-platelet ratio index (APRI) score. Group comparisons were made using ANOVA tests.

Results:

The patients were divided into three groups according to APRI scores: no fibrosis (≤0.5; n=41), moderate fibrosis (0.5–1.5; n=23), and significant fibrosis (>1.5; n=21). The values of MaxDisp were 2.9±0.9 (mean±SD), 2.3±0.7, and 2.1±0.6 in the no fibrosis, moderate fibrosis, and significant fibrosis groups, respectively (P<0.001); the corresponding values of MaxP1 were 0.05±0.2, 0.04±0.02, and 0.03±0.01, respectively (P=0.002), while those of MinP2 were –0.07±0.02, –0.05±0.02, and –0.04±0.01, respectively (P<0.001).

Conclusions:

Tagged MRI to quantify cardiac-induced liver motion can be easily incorporated in routine liver MRI and may represent a helpful complementary tool in the diagnosis of early liver fibrosis.

Quantitative elastography of liver fibrosis and spleen stiffness in chronic hepatitis B carriers: comparison of shear-wave elastography and transient elastography with liver biopsy correlation

PURPOSE

To document utility of shear-wave (SW) elastography for assessing liver fibrosis in chronic hepatitis B and to compare its performance with that of transient elastography.

MATERIALS AND METHODS

Ethics committee approved the study, and informed consent was obtained. Patients with liver biopsy correlation (n = 226) and healthy patients (n = 171) were analyzed. Results of SW elastography of liver, SW elastography of spleen, and transient elastography of liver were compared and correlated according to METAVIR scores. Areas under the receiver operating characteristic curve (AUCs), binary logistic regression, and Delong test were used.

RESULTS

AUC for SW elastography of liver, transient elastography of liver, and SW elastography of spleen was, respectively, 0.86, 0.80, and 0.81 for fibrosis (≥ F1 stage); 0.88, 0.78, and 0.82 for moderate fibrosis (≥ F2 stage); 0.93, 0.83, and 0.83 for severe fibrosis (≥ F3 stage); and 0.98, 0.92, and 0.84 for cirrhosis (F4 stage). SW elastography of liver showed significantly higher accuracy than transient elastography of liver and SW elastography of spleen in all fibrosis stages (P = .01-.04). SW elastography of spleen showed similar accuracy with transient elastography of liver (P = .21-.99). Combination SW elastography of liver and SW elastography of spleen to predict fibrosis staging showed diagnostic accuracy not further improved compared with SW elastography of liver alone (similar AUC; ≥ F1, P = .87; ≥ F2, P = .81; ≥ F3, P = .84; ≥ F4, P = .88). SW elastography of liver had higher successful rate than transient elastography of liver (98.9% vs 89.6%). Prevalence of discordance in at least two stages with liver histologic staging was 10.2% (23 of 226) for SW elastography of liver and 28.2% (58 of 206) for SW elastography of spleen.

CONCLUSION

SW elastography provides more accurate correlation of liver elasticity with liver fibrosis stage compared with transient elastography, especially in identification of stage F2 or greater.

Molecular MR imaging of liver fibrosis: a feasibility study using rat and mouse models

BACKGROUND & AIMS

Liver biopsy, the current clinical gold standard for fibrosis assessment, is invasive and has sampling errors, and is not optimal for screening, monitoring, or clinical decision-making. Fibrosis is characterized by excessive accumulation of extracellular matrix proteins including type I collagen. We hypothesize that molecular magnetic resonance imaging (MRI) with a probe targeted to type I collagen could provide a direct and non-invasive method of fibrosis assessment.

METHODS

Liver fibrosis was induced in rats with diethylnitrosamine and in mice with carbon tetrachloride. Animals were imaged prior to and immediately following i.v. administration of either collagen-targeted probe EP-3533 or non-targeted control Gd-DTPA. Magnetic resonance (MR) signal washout characteristics were evaluated from T1 maps and T1-weighted images. Liver tissue was subjected to pathologic scoring of fibrosis and analyzed for gadolinium and hydroxyproline.

RESULTS

EP-3533-enhanced MR showed greater signal intensity on delayed imaging (normalized signal enhancement mice: control=0.39 ± 0.04, fibrotic=0.55 ± 0.03, p<0.01) and slower signal washout in the fibrotic liver compared to controls (liver t(1/2)=51.3 ± 3.6 vs. 42.0 ± 2.5 min, p<0.05 and 54.5 ± 1.9 vs. 44.1 ± 2.9 min, p<0.01 for fibrotic vs. controls in rat and mouse models, respectively). Gd-DTPA-enhanced MR could not distinguish fibrotic from control animals. EP-3533 gadolinium concentration in the liver showed strong positive correlations with hydroxyproline levels (r=0.74 (rats), r=0.77 (mice)) and with Ishak scoring (r=0.84 (rats), r=0.79 (mice)).

CONCLUSIONS

Molecular MRI of liver fibrosis with a collagen-specific probe identifies fibrotic tissue in two rodent models of disease.

Transient elastography for assessment of fibrosis in paediatric liver disease

The prognosis and management of chronic liver diseases in children largely depend on the extent and progression of liver fibrosis, which is often the most important predictor of disease outcome, and thus influences the indication for potential therapy. Unfortunately, liver biopsy continues to be the gold standard for the staging and grading of fibrosis. Liver biopsy is an invasive and painful technique with several limitations. These limitations have led to the development of alternative noninvasive methods for the accurate assessment of fibrosis and for the maintenance of an acceptable risk/benefit ratio. In the last decades, transient elastography (TE) has received increasing consideration as a means of evaluating disease progression in paediatric chronic liver disease. TE is an accurate and reproducible methodology for identifying subjects without fibrosis or significant fibrosis, or with advanced fibrosis. In this review, we provide an outline of liver fibrosis in paediatric liver diseases, including fibrogenesis, and noninvasive techniques for the diagnosis and follow-up of fibrosis, and then focus on the characteristics of TE and on its strength in the assessment of liver fibrosis, paying particular attention to studies conducted in children.

Liver fibrosis in paediatric liver diseases

Numerous paediatric liver diseases from different origins may be complicated by development of liver fibrosis and progression to cirrhosis. Although fibrogenesis, which represents a major driving force for the development of liver fibrosis, has common tracts whatever the aetiology, liver fibrosis has different histopathological patterns in paediatric liver disease. In these diseases management choices may depend upon the stage of liver fibrosis. Thus, the accurate estimation of histological pattern of liver fibrosis is important for the prevention of the subsequent complications. Liver biopsy has long been considered as a gold standard diagnostic method for assessing liver fibrosis. However, due to its several disadvantages, in the last decades alternative and accurate non-invasive means to estimate fibrosis are developed. In this review, we characterised the most frequent histological patterns of liver fibrosis in paediatric liver diseases. Furthermore, we describe use of liver biopsy in diagnosis and staging of liver fibrosis, list the alternative non-invasive techniques that have an emerging role in the assessment of liver fibrosis, and propose a management algorithm.

Liver stiffness assessment by tagged MRI of cardiac-induced liver motion

Cirrhosis is an important and growing public health problem, affecting millions of Americans and many more people internationally. A pathological hallmark of the progression to cirrhosis is the development of liver fibrosis, so that monitoring the appearance and progression of liver fibrosis can be used to guide therapy. Here, we report a method to use magnetization-tagged magnetic resonance imaging to measure the cardiac-induced motion and deformation in the liver, as a means for noninvasively assessing liver stiffness, which is related to fibrosis. The initial results show statistically significant differences between healthy and cirrhotic subjects in the direct comparisons of the maximum displacement (mm), and the maximum (P1) and minimum (P2) two-dimensional strains, through the cardiac cycle (3.514 ± 0.793, 2.184 ± 0.611; 0.116 ± 0.043, 0.048 ± 0.011; -0.094 ± 0.020, -0.041 ± 0.015; healthy, cirrhosis, respectively; P < 0.005 for all). There are also significant differences in the displacement-normalized P1 and P2 strains (mm(-1) ) (0.030 ± 0.008, 0.017 ± 0.007; -0.024 ± 0.006, -0.013 ± 0.004; healthy, cirrhosis, respectively; P < 0.005 for all). Therefore, this noninvasive imaging-based method is a promising means to assess liver stiffness using clinically available imaging tools.

A brief review on molecular, genetic and imaging techniques for HCV fibrosis evaluation

Background

Chronic HCV is one of the major causes of morbidity and mortality in the present day world. The assessment of disease progression not only provides useful information for diagnosis and therapeutic supervision judgment but also for monitoring disease. Different invasive and non invasive methods are applied to diagnose the disease from initial to end stage (mild fibrosis to cirrhosis). Although, liver biopsy is still considered as gold standard to identify liver histological stages, an assessment of the disease development based on non-invasive clinical findings is also emerging and this may replace the need of biopsy in near future. This review gives brief insight on non-invasive methods currently available for predicting liver fibrosis in HCV with their current pros and cons to make easier for a clinician to choose better marker to assess liver fibrosis in HCV infected patients.

Methods

More than 200 studies regarding invasive and noninvasive markers available for HCV liver disease diagnosis were thoroughly reviewed. We examined year wise results of these markers based on their sensitivity, specificity, PPV, NPV and AUROCs.

Results

We found that in all non-invasive serum markers for HCV, FibroTest, Forn's Index, Fibrometer and HepaScore have high five-year predictive value but with low AUROCs (0.60~0.85) and are not comparable to liver biopsy (AUROC = 0.97). Even though from its beginning, Fibroscan is proved to be best with high AUROCs (> 0.90) in all studies, no single noninvasive marker is able to differentiate all fibrosis stages from end stage cirrhosis. Meanwhile, specific genetic markers may not only discriminate fibrotic and cirrhotic liver but also differentiate individual fibrosis stages.

Conclusions

There is a need of marker which accurately determines the stage based on simplest routine laboratory test. Genetic marker in combination of imaging technique may be the better non invasive diagnostic method in future.

Thrombocytopenia is more severe in patients with advanced chronic hepatitis C than B with the same grade of liver stiffness and splenomegaly

BACKGROUND AND AIM

The mechanism responsible for thrombocytopenia in chronic liver diseases (CLD) is not yet fully understood. The prevalence of thrombocytopenia has been reported to be higher in patients with hepatitis C virus-related hepatocellular carcinoma (CLD-C) than in those with hepatitis B virus-related hepatocellular carcinoma (CDC-B). We have examined the potential difference in thrombocytopenia between patients with CLD-B and those with CLD-C in terms of liver fibrosis adjustment and splenomegaly.

METHODS

The study cohort consisted of 102 patients with CLD-B and 143 patients with CLD-C were enrolled. Liver stiffness, which is reported to be well correlated with the degree of liver fibrosis, was measured by transient elastography.

RESULTS

The analysis of covariance with liver stiffness as a covariate revealed that the platelet count was lower in CLD-C patients than in CLD-B patients. Following stratification for liver stiffness, thrombocytopenia was found to be more severe in CLD-C patients than CLD-B patients with advanced liver stiffness, whereas the degree of splenomegaly was not significantly different. The plasma thrombopoietin level was not different between CLD-B and CLD-C patients with advanced liver stiffness, and the immature platelet number was lower in CLD-C patients despite thrombocytopenia being more severe in these patients.

CONCLUSIONS

CLD-C patients with advanced liver stiffness presented with more severe levels of thrombocytopenia than CLD-B patients even with the same grade of splenomegaly. Impaired platelet production rather than enhanced platelet destruction may underlie the mechanism responsible for thrombocytopenia in patients with CLD.

Transient elastography in patients with cystic fibrosis

BACKGROUND

Hepatic involvement is frequent in patients with cystic fibrosis (CF), with focal biliary cirrhosis being the pathognomonic hepatic manifestation. In around one-quarter of CF patients, it results in CF-associated liver disease (CFLD). This occurs as a relatively early complication with the majority of patients presenting in childhood or their early teens. However, a normal US does not preclude significant liver fibrosis and liver biopsy is an invasive procedure that is hampered by potential sampling errors. Transient elastography (TE) (Fibroscan) is a non-invasive, user-friendly and quick technique that provides an objective and reproducible measure of liver stiffness. This is accomplished with a device using an US probe mounted in the axis of a vibrator. Vibrations are transmitted by the transducer, inducing an electronic shear wave that propagates through the underlying tissue.

OBJECTIVES

We aimed to prospectively compare TE and transabdominal US scanning in children and adults attending a CF clinic.

MATERIALS AND METHODS

A total of 134 consecutive patients with documented CF were prospectively studied. In each case, transient elastography measurement was performed immediately after the routine annual US evaluation of the liver. Sonographic appearance of the liver was classified from 1 to 5. Ten validated TE measurements were performed in each patient with the result expressed in kilopascals (kPa). The median value was considered representative of the elastic modulus of the liver.

RESULTS

Measurements were performed in 59 CF adults, 75 CF children and 31 control children. There was no relationship between age and liver stiffness in either the control group or CF patients. Elasticity values of controls, CF pancreatic sufficient (PS) patients and pancreatic insufficient (PI) CF patients with a US score <3 were comparable and significantly lower than in CF patients with a US score > or = 3 (all PI) (P < 0.002). Median elasticity in CF patients was significantly higher in males (4.7 kPa) than in females (3.9 kPa) (P = 0.0013).

CONCLUSION

Considering the limitations of US and the low risk-benefit rate of liver biopsy in most CF patients, this preliminary study suggests that TE is an attractive non-invasive way to assess and follow-up liver disease in these patients.

Staging of liver fibrosis in chronic hepatitis B patients with a composite predictive model: A comparative study

AIM: To evaluate the efficacy of 6 noninvasive liver fibrosis models and to identify the most valuable model for the prediction of liver fibrosis stage in chronic hepatitis B (CHB) patients.

METHODS: Seventy-eight CHB patients were consecutively enrolled in this study. Liver biopsy was performed and blood serum was obtained at admission. Histological diagnosis was made according to the METAVIR system. Significant fibrosis was defined as stage score ≥ 2, severe fibrosis as stage score ≥ 3. The diagnostic accuracy of 6 noninvasive liver fibrosis models, including serum aspartate aminotransferase (AST) to platelet ratio index (APRI), FIB-4, Forn’s index, Fibrometer, Hepascore, and Shanghai Liver Fibrosis Group’s index (SLFG), was investigated.

RESULTS: The APRI, FIB-4 and Forn’s index under receiver operating characteristic curve (AUROC) for significant fibrosis were 0.71, 0.75 and 0.79, respectively, with a diagnosis accuracy of 67%, 77% and 80%, respectively, and 0.80, 0.87 and 0.86, respectively, under the AUROC for severe fibrosis. The Hepascore, SLFG, and Fibrometer were 0.80, 0.83 and 0.85, respectively under the AUROC for significant fibrosis (P < 0.01). The diagnosis accuracy of Hepascore and SLFG was 86% and 88%, respectively. The Hepascore, SLFG, and Fibrometer were 0.95, 0.93, and 0.94, respectively, under the AUROC for severe fibrosis (P < 0.01).

CONCLUSION: The models containing direct serum markers have a better diagnostic value than those not containing direct serum markers.

FibroScan and ultrasonography in the prediction of hepatic fibrosis in patients with chronic viral hepatitis

BACKGROUND

The aim of this study was to assess the diagnostic performances of liver stiffness measurement (LSM), ultrasonography (US) and their combined use in predicting the extent of hepatic fibrosis.

METHODS

Consecutive patients with chronic hepatitis B (HBV) or hepatitis C virus (HCV) infections, with indications for liver biopsy, were prospectively enrolled. LSM was performed on the same day as biopsy. US scores, including assessment of liver surface, liver parenchyma, intrahepatic vessels and spleen index, were used to assess the degree of hepatic fibrosis. The pathological findings were used as a reference standard and diagnostic accuracy was assessed and compared.

RESULTS

Three-hundred and twenty patients, including 199 men and 121 women, with a mean age of 50.8 years, were analyzed. There were 214 (66.9%) HCV patients, 88 (27.5%) HBV patients and 18 (5.6%) patients with both HCV and HBV. LSM correlated significantly with the hepatic fibrosis (F) scores, necro-inflammatory activity and US scores in multivariate analysis. The diagnostic accuracy of LSM is significantly superior to US, and equal to combined LSM with US, in the prediction of all HCV-related fibrosis scores. The cut-off value of LSM is 6 kPa for diagnosing F > =1, with a positive predictive value of 91%. Also, the cut-off value is 12 kPa for the prediction of cirrhosis, with a negative predictive value of 94%.

CONCLUSIONS

LSM is useful for predicting hepatic fibrosis and excluding cirrhosis. A combination of LSM and US does not improve the accuracy in assessing hepatic fibrosis.

Coinheritance of hereditary spherocytosis and reversibility of cirrhosis in a young female patient with hereditary hemochromatosis

Here we report a 33-years-old woman with hereditary spherocytosis and hemochromatosis due to homozygosity for the C282Y mutation of the HFE gene. The coinheritance of both conditions led to severe iron overload and liver cirrhosis at young age. The patient was treated by repeated phlebotomy, and reversibility of cirrhosis was documented by transient elastography. This report discusses the pathophysiology of iron accumulation in patients with hemolytic anemia combined with HFE C282Y homozygosity. The case indicates that patients with hematological disorders characterized by increased erythropoetic activity should be screened for HFE mutations.

Measurement of liver stiffness with two imaging techniques: magnetic resonance elastography and ultrasound elastometry

PURPOSE

To cross-validate the magnetic resonance elastography (MRE) technique with a clinical device, based on an ultrasound elastometry system called Fibroscan.

MATERIALS AND METHODS

Ten healthy subjects underwent an MRE and a Fibroscan test. The MRE technique used a round pneumatic driver at 60 Hz to generate shear waves inside the liver. An elastogram representing a map of the liver stiffness was generated allowing for the measurement of the average liver stiffness inside a region of interest. The Fibroscan technique used an ultrasound probe (3.5 MHz) composed of a vibrator that sent low-frequency (50 Hz) shear waves inside the right liver lobe. The probe acts as an emitter-receptor that measures the velocity of the waves propagated inside the liver tissue.

RESULTS

The mean shear stiffness measured with the MRE and Fibroscan techniques were 1.95+/-0.06 kPa and 1.79+/-0.30 kPa, respectively. A higher standard deviation was found for the same subject with Fibroscan.

CONCLUSION

This study shows why MRE should be investigated beyond the Fibroscan. The MRE technique provided elasticity of the entire liver, meanwhile the Fibroscan provided values of elasticity locally.

Can imaging modalities diagnose and stage hepatic fibrosis and cirrhosis accurately?

The accurate diagnosis and staging of hepatic fibrosis is crucial for prognosis and treatment of liver disease. The current gold standard, liver biopsy, cannot be used for population-based screening, and has well known drawbacks if used for monitoring of disease progression or treatment success. Our objective was to assess performance and promise of radiologic modalities and techniques as alternative, noninvasive assessment of hepatic fibrosis. A systematic review was conducted. Six hundred twenty-eight studies were identified via electronic search. One hundred fifty-three papers were reviewed. Most described techniques that could differentiate between cirrhosis or severe fibrosis and normal liver. Accurate staging of fibrosis or diagnosis of mild fibrosis was often not achievable. Ultrasonography is the most common modality used in the diagnosis and staging of hepatic fibrosis. Elastographic measurements, either ultrasonography-based or magnetic resonance-based, and magnetic resonance diffusion weighted imaging, show the most promise for accurate staging of hepatic fibrosis. Most currently available imaging techniques can detect cirrhosis or significant fibrosis reasonably accurately. However, to date only magnetic resonance elastography has been able to stage fibrosis or diagnose mild disease. Utrasonographic elastography and magnetic resonance diffusion weighted appear next most promising.