Use of Liver Imaging and Biopsy in Clinical Practice

A practical clinical approach to liver fibrosis

Liver fibrosis is a slow, insidious process involving accumulation of extracellular matrix protein in the liver. The stage of liver fibrosis in chronic liver disease (CLD) determines overall morbidity and mortality; the higher the stage, the worse the prognosis. Noninvasive composite scores can be used to determine whether patients with CLD have significant or advanced fibrosis. Patients with low composite scores can be safely followed up in primary care with periodic reassessment. Those with higher scores should be referred to a specialist. As the epidemic of diabetes mellitus, obesity and non-alcoholic fatty liver diseases is rising, CLD is becoming more prevalent. Easy-to-use fibrosis assessment composite scores can identify patients with minimal or advanced fibrosis, and should be an integral part of decision-making. Patients with cirrhosis, high composite scores, chronic hepatitis B with elevated alanine aminotransferase and aspartate aminotransferase, or deranged liver panel of uncertain aetiology should be referred to a specialist.

Clinical outcomes and management of patients with chronic hepatitis B and liver stiffness measurement in the grey zone

BACKGROUND

A significant number of patients have liver stiffness measurements in the grey zone where liver biopsy is recommended.

AIMS

To study chronic hepatitis B patients with initial liver stiffness measurements in the grey zone with regards to rates of liver biopsy, repeat liver stiffness measurements and outcomes.

METHODS

Consecutive chronic hepatitis B patients who underwent transient elastography from August 2006 to July 2017 were retrospectively studied. Liver-related events were defined as hepatocellular carcinoma or cirrhotic complications. Grey zone was defined as liver stiffness measurements: 6.1-9.0 kPa (normal ALT) or 7.6-12.0 kPa (ALT 1-5 × upper limit of normal) on M-probe and 6.9-10.0 kPa on XL-probe.

RESULTS

Of the 3212 patients analysed, 837 (26%) had initial liver stiffness measurements in grey zone. Only 3.6% of grey zone patients proceeded to liver biopsy within 6 months of transient elastography, of which 33% had METAVIR F3-4 fibrosis. Repeat liver stiffness measurements was performed in 44% of grey zone patients. Liver biopsy and repeat liver stiffness measurements prompted change in management in 47% and 31% of patients respectively. Independent predictors for liver-related events in grey zone patients included increased age, low albumin and low platelet count. Liver-related events rates were increased (9%-17%) in patients with METAVIR > F2 fibrosis on biopsy or repeat liver stiffness measurements which did not improve.

CONCLUSIONS

Chronic hepatitis B patients with initial liver stiffness measurements in the grey zone rarely proceed to a clarifying liver biopsy which would reveal advanced fibrosis or cirrhosis in one-third of patients. Both liver biopsy and repeat liver stiffness measurements in grey zone patients have clinical utility in prompting changes in management and providing prognostic information.

Current trials and novel therapeutic targets for alcoholic hepatitis

Alcoholic hepatitis is a clinical syndrome in which patients present with acute-on-chronic liver failure and a high risk of short-term mortality. The current treatment of alcoholic hepatitis is suboptimal. Results recently published from the STOPAH study have improved our understanding of how best to design clinical trials for this condition. Although emerging data on liver transplantation for patients with alcoholic hepatitis are encouraging, less than 2% of these patients qualify. Clearly, there is an unmet need for novel treatments to improve the survival of these patients. Changes in the gut microbiota, inflammatory and cytokine signalling, oxidative stress and mitochondrial dysfunction, and abnormalities in the hepatic regenerative capacity alone or in combination contribute to the pathology of alcoholic hepatitis. In this chapter, we will describe the novel therapeutic agents targeting various pathways in the pathophysiology of alcoholic hepatitis. Specifically, we will describe the ongoing clinical trials in which some of these agents are being studied.

The Role of EUS in Liver Biopsy

PURPOSE OF REVIEW

EUS-guided liver biopsy (EUS-LB) is being used with increased frequency to perform parenchymal liver biopsy. Evolution of the technique can now achieve excellent liver tissue cores. This review covers important developments in this procedure.

RECENT FINDINGS

Clinical studies have recently demonstrated that the 19G EUS core biopsy needle is superior to non-core needles for liver tissue acquisition. In addition, wet suction provides more robust tissue samples than dry suction. Heparin priming of the needle (instead of saline) can prevent blood clogging within the needle lumen. A 1-hour recovery time after the EUS-LB is sufficient in almost all cases. The EUS-LB can deliver bilobar biopsies, which can decrease sampling error. Patients who need a liver biopsy in addition to an endoscopy or EUS are best served by the EUS-LB, as the combination procedure saves time and cost. The EUS-LB is a safe and effective means for procuring good liver core biopsies. Incremental improvements in technique have increased quality of the resulting specimen. Future directions of this technique are discussed.

Longitudinal correlations between MRE, MRI-PDFF, and liver histology in patients with non-alcoholic steatohepatitis: Analysis of data from a phase II trial of selonsertib

BACKGROUND & AIMS

Non-invasive tools for monitoring treatment response and disease progression in non-alcoholic steatohepatitis (NASH) are needed. Our objective was to evaluate the utility of magnetic resonance (MR)-based hepatic imaging measures for the assessment of liver histology in patients with NASH.

METHODS

We analyzed data from patients with NASH and stage 2 or 3 fibrosis enrolled in a phase II study of selonsertib. Pre- and post-treatment assessments included centrally read MR elastography (MRE)-estimated liver stiffness, MR imaging-estimated proton density fat fraction (MRI-PDFF), and liver biopsies evaluated according to the NASH Clinical Research Network classification and the non-alcoholic fatty liver disease activity score (NAS).

RESULTS

Among 54 patients with MRE and biopsies at baseline and week 24, 18 (33%) had fibrosis improvement (≥1-stage reduction) after undergoing 24 weeks of treatment with the study drug. The area under the receiver operating characteristic curve (AUROC) of MRE-stiffness to predict fibrosis improvement was 0.62 (95% CI 0.46-0.78) and the optimal threshold was a ≥0% relative reduction. At this threshold, MRE had 67% sensitivity, 64% specificity, 48% positive predictive value, 79% negative predictive value. Among 65 patients with MRI-PDFF and biopsies at baseline and week 24, a ≥1-grade reduction in steatosis was observed in 18 (28%). The AUROC of MRI-PDFF to predict steatosis response was 0.70 (95% CI 0.57-0.83) and the optimal threshold was a ≥0% relative reduction. At this threshold, MRI-PDFF had 89% sensitivity and 47% specificity, 39% positive predictive value, and 92% negative predictive value.

CONCLUSIONS

These preliminary data support the further evaluation of MRE-stiffness and MRI-PDFF for the longitudinal assessment of histologic response in patients with NASH.

LAY SUMMARY

Liver biopsy is a potentially painful and risky method to assess damage to the liver due to non-alcoholic steatohepatitis (NASH). We analyzed data from a clinical trial to determine if 2 methods of magnetic resonance imaging - 1 to measure liver fat and 1 to measure liver fibrosis (scarring) - could potentially replace liver biopsy in evaluating NASH-related liver injury. Both imaging methods were correlated with biopsy in showing the effects of NASH on the liver.

SCCA-IgM as a Potential Biomarker of Non-Alcoholic Fatty Liver Disease in Patients with Obesity, Prediabetes and Diabetes Undergoing Sleeve Gastrectomy

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) has a high prevalence in obesity and its presence should be screened. Laparoscopic sleeve gastrectomy (LSG) is an effective treatment for obesity, but its effects on NAFLD are still to be firmly established. The diagnosis of non-alcoholic steatohepatitis (NASH) is currently performed by liver biopsy, a costly and invasive procedure. Squamous cell carcinoma antigen-IgM (SCCA-IgM) is a biomarker of viral hepatitis to hepatocellular carcinoma development and its role in NAFLD to NASH progression has not yet been investigated.

OBJECTIVE

The aim of this study was to evaluate SCCA-IgM as a non-invasive biomarker of NAFLD/NASH in patients with different degrees of metabolic-complicated obesity before and after LSG.

METHOD

Fifty-six patients with obesity were studied before and 12 months after LSG; anthropometric, biochemical, clinical, and imaging data were collected.

RESULTS

At baseline steatosis was strongly associated with the glycaemic profile (p = 0.016) and was already present in prediabetic patients with obesity (82%). Only 3 patients had an SCCA-IgM level above the normal cut-off. SCCA-IgM titre did not change according to glycaemic profile or steatosis. Metabolic and inflammatory factors and transaminases significantly reduced after LSG-induced weight loss, except for SCCA-IgM. The ALT/AST ratio decreased post-LSG correlated with BMI (r = 0.297, p = 0.031), insulin (r = 0.354, p = 0.014), and triglycerides (r = 0.355, p = 0.009) reduction.

CONCLUSIONS

Our results confirm the tight link between NAFLD and metabolic complications, suggesting prediabetes as a new risk factor of steatosis. SCCA-IgM does not seem to have a role in the identification and prognosis of NAFLD.

The role of noninvasive tests and liver biopsy in the diagnosis of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is characterized by hepatic steatosis in the absence of significant alcohol consumption (<40 g/week). The essential metabolic trait is insulin resistance, which is why NAFLD is associated with obesity, diabetes mellitus (DM), hyperlipidemia.

Approximately one-quarter of adults with NAFLD present nonalcoholic steatohepatitis (NASH) leading to progressive hepatic fibrosis and finally cirrhosis and hepatocellular carcinoma.

If liver biopsy (LB) has traditionally been NAFLD’s gold standard, over the past 15 years, its use has undergone an important transformation.

In this review, the role of noninvasive tests (serological markers, imaging techniques) in the NAFLD evaluation is analyzed, starting from the low adherence of patients for LB, the complications of the technique, and the increased cost.

LB is the only investigation that distinguishes between simple steatosis and NASH.

However, in the medical practice, LB has gained lesser value; it is worth mentioning that NASH represents a small proportion compared to NAFLD. For this reason, most patients only show biopsy steatosis, which has a good prognosis. In addition, judging by the appearance of inflammation markers and fibrosis in the diagnosis technique, the use of LB has become increasingly rare in the definition of NASH.

Evaluation of texture features at staging liver fibrosis based on phase contrast X-ray imaging

BACKGROUND

The purpose of this study is to explore the potential of phase contrast imaging to detect fibrotic progress in its early stage; to investigate the feasibility of texture features for quantified diagnosis of liver fibrosis; and to evaluate the performance of back propagation (BP) neural net classifier for characterization and classification of liver fibrosis.

METHODS

Fibrous mouse liver samples were imaged by X-ray phase contrast imaging, nine texture measures based on gray-level co-occurrence matrix were calculated and the feasibility of texture features in the characterization and discrimination of liver fibrosis at early stages was investigated. Furthermore, 36 or 18 features were applied to the input of BP classifier; the classification performance was evaluated using receiver operating characteristic curve.

RESULTS

The phase contrast images displayed a vary degree of texture pattern from normal to severe fibrosis stages. The BP classifier could distinguish liver fibrosis among normal, mild, moderate and severe stages; the average accuracy was 95.1% for 36 features, and 91.1% for 18 features.

CONCLUSION

The study shows that early stages of liver fibrosis can be discriminated by the morphological features on the phase contrast images. BP network model based on combination of texture features is demonstrated effective for staging liver fibrosis.

Virtual Consultations Through the Veterans Administration SCAN-ECHO Project Improves Survival for Veterans With Liver Disease

Access to specialty care has been associated with improved survival in patients with liver disease but universal access is not always feasible. Methods of care delivery using virtual modalities including the SCAN-ECHO (Specialty Access Network-Extension of Community Healthcare Outcome) program were implemented by the Veterans Health Administration (VHA) to address this need but limited data are available on patient outcomes. We sought to evaluate the efficacy of a SCAN-ECHO visit within the context of a regional cohort of patients with liver disease in the VHA (n = 62,237) following implementation in the Ann Arbor SCAN-ECHO Liver Clinic from June 1, 2011, to March 31, 2015. The effect of a SCAN-ECHO visit on all-cause mortality was compared with patients with no liver clinic visit. To adjust for the differences among patients who had a SCAN-ECHO visit versus those with no visit, propensity score matching was performed on condition factors that affect the likelihood of a SCAN-ECHO visit: demographics, geographic location, liver disease diagnosis, severity, and comorbidities. During the study period, 513 patients who had a liver SCAN-ECHO visit were found within the cohort. Patients who had completed a virtual SCAN-ECHO visit were more likely younger, rural, with more significant liver disease, and evidence for cirrhosis. Propensity-adjusted mortality rates using the Cox Proportional Hazard Model showed that a SCAN-ECHO visit was associated with a hazard ratio of 0.54 (95% confidence interval 0.36-0.81, P = 0.003) compared with no visit. Conclusion: Improved survival in patients using SCAN-ECHO suggests that this approach may be an effective method to improve access for selected patients with liver disease, particularly in rural and underserved populations where access to specialty care is limited.

Transfer learning with deep convolutional neural network for liver steatosis assessment in ultrasound images

PURPOSE

The nonalcoholic fatty liver disease is the most common liver abnormality. Up to date, liver biopsy is the reference standard for direct liver steatosis quantification in hepatic tissue samples. In this paper we propose a neural network-based approach for nonalcoholic fatty liver disease assessment in ultrasound.

METHODS

We used the Inception-ResNet-v2 deep convolutional neural network pre-trained on the ImageNet dataset to extract high-level features in liver B-mode ultrasound image sequences. The steatosis level of each liver was graded by wedge biopsy. The proposed approach was compared with the hepatorenal index technique and the gray-level co-occurrence matrix algorithm. After the feature extraction, we applied the support vector machine algorithm to classify images containing fatty liver. Based on liver biopsy, the fatty liver was defined to have more than 5% of hepatocytes with steatosis. Next, we used the features and the Lasso regression method to assess the steatosis level.

RESULTS

The area under the receiver operating characteristics curve obtained using the proposed approach was equal to 0.977, being higher than the one obtained with the hepatorenal index method, 0.959, and much higher than in the case of the gray-level co-occurrence matrix algorithm, 0.893. For regression the Spearman correlation coefficients between the steatosis level and the proposed approach, the hepatorenal index and the gray-level co-occurrence matrix algorithm were equal to 0.78, 0.80 and 0.39, respectively.

CONCLUSIONS

The proposed approach may help the sonographers automatically diagnose the amount of fat in the liver. The presented approach is efficient and in comparison with other methods does not require the sonographers to select the region of interest.

An update on the recent advances in antifibrotic therapy

Chronic injury to the liver, such as viral hepatitis, alcoholism, non-alcoholic fatty liver disease (NAFLD) or nonalcoholic steatohepatitis (NASH), promotes extracellular matrix deposition and organ scarring, termed hepatic fibrosis. Fibrosis might progress to cirrhosis and predisposes to hepatocellular carcinoma (HCC), but is also associated with extrahepatic morbidity and mortality in NAFLD/NASH. The improved understanding of pathogenic mechanisms underlying chronic inflammation and fibrogenesis in the liver prompted recent advances in antifibrotic therapies. Areas covered: We review recent advances in antifibrotic therapy, of which most are currently tested in clinical trials for NAFLD or NASH. This explains the manifold metabolic pathways as antifibrotic targets, including farnesoid X receptor (FXR) agonism (obeticholic acid, nonsteroidal FXR agonists), acetyl-CoA carboxylase inhibition, peroxisome proliferator-activator receptor agonism (elafibranor, lanifibranor, saroglitazar), and fibroblast growth factor (FGF)-21 or FGF-19 activation. Other antifibrotic drug candidates target cell death or inflammation, such as caspase (emricasan) or ASK1 inhibitors (selonsertib), galectin-3 inhibitors and reducing inflammatory macrophage recruitment by blocking chemokine receptors CCR2/CCR5 (cenicriviroc). Expert commentary: The tremendous advances in translational and clinical research fuels the hope for efficacious antifibrotic therapies within the next 5 years. Very likely, a combination of etiology-specific, metabolic, anti-inflammatory, and direct antifibrotic interventions will be most effective.

Candidate Biomarkers of Liver Fibrosis: A Concise, Pathophysiology-oriented Review

Repair of sustained liver injury results in fibrosis (i.e. the accumulation of extracellular matrix proteins), and ultimately the complete distortion of parenchymal architecture of the liver, which we call cirrhosis. Detecting and staging of fibrosis is thus a mainstay in the management of chronic liver diseases, since many clinically relevant decisions, such as starting treatment and/or monitoring for complications including hepatocellular carcinoma, may depend on it. The gold standard for fibrosis staging is liver biopsy, the role of which, however, is questioned nowadays because of cost, hazards and poor acceptance by patients. On the other hand, imaging techniques and/or measurement of direct and indirect serum markers have not proved to be completely satisfactory under all circumstances as alternatives to liver biopsy. Making progress in this field is now more crucial than ever, since treatments for established fibrosis appear on the horizon. Fine dissection of the pathways involved in the pathophysiology of liver diseases has put forward several novel candidate biomarkers of liver fibrosis, such as growth arrest-specific6, Mac-2-binding protein, osteopontin, placental growth factor, growth/differentiation factor 15 and hepatocyte growth factor. All molecules have been suggested to have potential to complement or substitute methods currently used to stage liver diseases. Here, we review the pros and cons for their use in this setting.

Usefulness of Enhanced Liver Fibrosis, Glycosylation Isomer of Mac-2 Binding Protein, Galectin-3, and Soluble Suppression of Tumorigenicity 2 for Assessing Liver Fibrosis in Chronic Liver Diseases

BACKGROUND

Liver biopsies have been partially replaced by noninvasive methods for assessing liver fibrosis. We explored the usefulness of four novel biomarkers, enhanced liver fibrosis (ELF), glycosylation isomer of Mac-2 binding protein (M2BPGi), galectin-3, and soluble suppression of tumorigenicity 2 (sST2), in association with liver fibrosis.

METHODS

ELF, M2BPGi, galectin-3, and sST2 were assayed in 173 patients with chronic liver diseases. The results were analyzed according to fibrosis grade (F0/1, F2, and F3/4) by transient elastography (TE).

RESULTS

ELF, M2BPGi, galectin-3, and sST2 values differed significantly according to TE grade; ELF and M2BPGi values were higher in F2 and F3/4 than in F0/1 (P≤0.001, all), sST2 values were higher in F3/4 than in F0/1 and F2 (P<0.05), and galectin-3 values were higher in F3/4 than in F0/1 (P=0.0036). ELF and M2BPGi showed good TE fibrosis detection performance (area under the curves [AUC], 0.841 and 0.833 for ≥F2; and 0.837 and 0.808 for ≥F3). The sensitivity and specificity for predicting TE grade F≥2 were 84.1% and 76.7% for ELF and 63.6% and 91.5% for M2BPGi.

CONCLUSIONS

This is the first study to compare the liver fibrosis assessment of four novel biomarkers: ELF, M2BPGi, galectin-3, and sST2. The biomarkers varied significantly according to TE grade, and each biomarker showed a different trend. ELF and M2BPGi seem to have comparable good performance for detecting liver fibrosis.

Clinical prediction of HBV and HCV related hepatic fibrosis using machine learning

Clinical prediction of advanced hepatic fibrosis (HF) and cirrhosis has long been challenging due to the gold standard, liver biopsy, being an invasive approach with certain limitations. Less invasive blood test tandem with a cutting-edge machine learning algorithm shows promising diagnostic potential. In this study, we constructed and compared machine learning methods with the FIB-4 score in a discovery dataset (n = 490) of hepatitis B virus (HBV) patients. Models were validated in an independent HBV dataset (n = 86). We further employed these models on two independent hepatitis C virus (HCV) datasets (n = 254 and 230) to examine their applicability. In the discovery data, gradient boosting (GB) stably outperformed other methods as well as FIB-4 scores (p < .001) in the prediction of advanced HF and cirrhosis. In the HBV validation dataset, for classification between early and advanced HF, the area under receiver operating characteristic curves (AUROC) of GB model was 0.918, while FIB-4 was 0.841; for classification between non-cirrhosis and cirrhosis, GB showed AUROC of 0.871, while FIB-4 was 0.830. Additionally, GB-based prediction demonstrated good classification capacity on two HCV datasets while higher cutoffs for both GB and FIB-4 scores were required to achieve comparable specificity and sensitivity. Using the same parameters as FIB-4, the GB-based prediction system demonstrated steady improvements relative to FIB-4 in HBV and HCV cohorts with different cutoff values required in different etiological groups. A user-friendly web tool, LiveBoost, makes our prediction models freely accessible for further clinical studies and applications.

Senescence mirrors the extent of liver fibrosis in chronic hepatitis C virus infection

BACKGROUND

Chronic viral hepatitis is linked to fibrotic liver injury that can progress to liver cirrhosis with its associated complications. Recent evidence suggests a role of senescence in liver fibrosis, although the senescence regulators contributing to fibrosis progression remain unclear.

AIM

To investigate the role of senescence and different senescence markers for fibrosis progression in patients with chronic hepatitis C virus (HCV) infection.

METHODS

The expression of the cell cycle inhibitors p21, p27 and p16 as well as the senescence markers p-HP1γ and γ-H2AX was analysed in liver tissue with different fibrosis stages. Senescence-associated chitotriosidase activity was measured in sera of HCV patients (n = 61) and age-matched healthy individuals (n = 22).

RESULTS

We found a remarkable up-regulation of the cell cycle inhibitors and senescence markers in chronic HCV infection compared to healthy liver tissue. Liver tissue with relevant fibrosis stages (F2-3) or cirrhosis (F4) revealed a significant increase in senescent cells compared to livers with no or minimal fibrosis (F0-1). In cirrhotic livers, a significantly higher number of p-HP1γ, p21 and p27 positive cells was detected compared to liver tissue with F2-3 fibrosis. Importantly, we identified T-cells as the dominant cell type contributing to increased senescence during fibrosis progression. Compared to healthy individuals, serum chitotriosidase was significantly elevated and correlated with histological fibrosis stages and liver stiffness as assessed by transient elastography.

CONCLUSIONS

Senescence of hepatic T-cells is enhanced in chronic viral hepatitis and increases with fibrosis progression. Serological detection of senescence-associated chitotriosidase might allow for the non-invasive detection of relevant fibrosis stages.

Grand Rounds: Alcoholic Hepatitis

A 33-year-old Caucasian male was admitted to hospital with recent onset of jaundice of 2-3 weeks duration. He reported heavy use of alcohol for the last 10 years with the last drink a day prior to the onset of symptoms. At admission, he was alert and oriented to time, place, and person, and was deeply jaundiced. His laboratory profile can be summarised as follows: haemoglobin 12.1 g/dl, white blood cell count 18,700 with 81% neutrophils, serum bilirubin 33 (direct 22) mg/dl, aspartate aminotransferase 147 IU/L, alanine aminotransferase 62 IU/L, alkaline phosphatase 117 IU/L, serum albumin 2.8 gm/dl, serum creatinine 0.6 mg/dl, prothrombin time 18.3 (control 14.5) seconds, and international normalized ratio 1.48. He was diagnosed with severe alcoholic hepatitis (Maddrey discriminant function score of 50) and treated with prednisolone for 28 days with symptomatic and biochemical improvement. His Lille score at seven days was 0.4, and his serum bilirubin had decreased to 3.5 mg/dl at the end of treatment. He was also seen by the addiction team during hospitalisation; he agreed to follow through on recommendations. He was dismissed after completing a three-week inpatient rehabilitation programme but relapsed to alcohol use three months later, and was readmitted with alcohol withdrawal. He was readmitted two months later (about six months from the first episode) for a second episode of severe alcoholic hepatitis. At admission, his model for end-stage liver disease score was 32 and he was treated again with corticosteroids. His Lille score at seven days was 0.6 and steroids were discontinued. The hospital course was complicated by spontaneous bacterial peritonitis and pneumonia with development of acute kidney injury. He continued to worsen, developing multiorgan failure. After a course of one month, the family's preference was for him to receive comfort measures. This scenario raises several questions.

Non-invasive prediction of NAFLD severity: a comprehensive, independent validation of previously postulated serum microRNA biomarkers

Liver biopsy is currently the only reliable method to establish nonalcoholic fatty liver disease (NAFLD) severity. However, this technique is invasive and occasionally associated with severe complications. Thus, non-invasive diagnostic markers for NAFLD are needed. Former studies have postulated 18 different serum microRNA biomarkers with altered levels in NAFLD patients. In the present study, we have re-examined the predictive value of these serum microRNAs and found that 9 of them (miR-34a, -192, -27b, -122, -22, -21, -197, -30c and -16) associated to NAFLD severity in our independent cohort. Moreover, miR-192, -27b, -22, -197 and -30c appeared specific for NAFLD, when compared with patients with drug-induced liver injury. Preliminary serum RNAseq analysis allowed identifying novel potential miRNA biomarkers for nonalcoholic steatohepatitis (NASH). The classification performance of validated miRNAs (and their ratios) for NASH was better than that reached by AST, whereas for advanced fibrosis prediction miRNAs did not perform better than the FIB-4 algorithm. Cross-validated models combining both clinical and miRNA variables showed enhanced predictivity. In conclusion, the circulating microRNAs validated demonstrate a better diagnostic potential than conventional serum markers to identify NASH patients and could complement and improve current fibrosis prediction algorithms. The research in this field is still open.

Free-breathing quantification of hepatic fat in healthy children and children with nonalcoholic fatty liver disease using a multi-echo 3-D stack-of-radial MRI technique

BACKGROUND

In adults, noninvasive chemical shift encoded Cartesian magnetic resonance imaging (MRI) and single-voxel magnetic resonance (MR) spectroscopy (SVS) accurately quantify hepatic steatosis but require breath-holding. In children, especially young and sick children, breath-holding is often limited or not feasible. Sedation can facilitate breath-holding but is highly undesirable. For these reasons, there is a need to develop free-breathing MRI technology that accurately quantifies steatosis in all children.

OBJECTIVE

This study aimed to compare non-sedated free-breathing multi-echo 3-D stack-of-radial (radial) MRI versus standard breath-holding MRI and SVS techniques in a group of children for fat quantification with respect to image quality, accuracy and repeatability.

MATERIALS AND METHODS

Healthy children (n=10, median age [±interquartile range]: 10.9 [±3.3] years) and overweight children with nonalcoholic fatty liver disease (NAFLD) (n=9, median age: 15.2 [±3.2] years) were imaged at 3 Tesla using free-breathing radial MRI, breath-holding Cartesian MRI and breath-holding SVS. Acquisitions were performed twice to assess repeatability (within-subject mean difference, MD_within). Images and hepatic proton-density fat fraction (PDFF) maps were scored for image quality. Free-breathing and breath-holding PDFF were compared using linear regression (correlation coefficient, r and concordance correlation coefficient, ρ_c) and Bland-Altman analysis (mean difference). P<0.05 was considered significant.

RESULTS

In patients with NAFLD, free-breathing radial MRI demonstrated significantly less motion artifacts compared to breath-holding Cartesian (P<0.05). Free-breathing radial PDFF demonstrated a linear relationship (P<0.001) versus breath-holding SVS PDFF and breath-holding Cartesian PDFF with r=0.996 and ρ_c=0.994, and r=0.997 and ρ_c=0.995, respectively. The mean difference in PDFF between free-breathing radial MRI, breath-holding Cartesian MRI and breath-holding SVS was <0.7%. Repeated free-breathing radial MRI had MD_within=0.25% for PDFF.

CONCLUSION

In this pediatric study, non-sedated free-breathing radial MRI provided accurate and repeatable hepatic PDFF measurements and improved image quality, compared to standard breath-holding MR techniques.

Noninvasive imaging biomarker assessment of liver fibrosis by elastography in NAFLD

NAFLD is a global epidemic. The prevalence of NAFLD is 20-30% in North America, northern Europe, Australia, Japan, India and China. It is crucial that patients with NAFLD receive an assessment for their risk of advanced fibrosis, which increases the risk of hepatocellular carcinoma and other complications of cirrhosis. Risk stratification that is efficient, cost-effective, patient-centred and evidence-based is one of the most important issues facing clinicians who care for those with liver disease. Given patients' preference to avoid liver biopsy, noninvasive alternatives to assess liver fibrosis are in high demand. The most accurate noninvasive methods are based on liver elastography. Research on these techniques - which include vibration-controlled transient elastography (VCTE), magnetic resonance elastography (MRE), shear-wave elastography and acoustic radiation force impulse - has proliferated. Unfortunately, the literature has not kept pace with clinical practice. There is limited guidance for how clinicians should anticipate and manage the pitfalls of these tests. Furthermore, guidance is unavailable for clinicians regarding the optimal incorporation of VCTE, MRE or the emerging elastographic techniques into their clinical strategy, particularly for patients with NAFLD. In this Review, we summarize the available evidence, highlight gaps to address in further research and explore optimization of these techniques in clinical practice.

Determinants of fibrosis progression and regression in NASH

Cirrhosis has become the major liver-related clinical endpoint in non-alcoholic steatohepatitis (NASH). However, progression to cirrhosis is less predictable in NASH than in other chronic liver diseases. This is due to the complex and multifactorial aetiology of NASH, which is determined by lifestyle and nutrition, multiple genetic and epigenetic factors, and a prominent role of hepatic and extrahepatic comorbidities. Thus, modest changes in these cofactors can also induce fibrosis regression, at least in patients with precirrhotic liver disease. Fibrogenesis in NASH correlates with, but is indirectly coupled to, classical inflammation, since fibrosis progression is driven by repetitive periods of repair. While hepatocyte lipoapoptosis is a key driving force of fibrosis progression, activated hepatic stellate cells, myofibroblasts, cholangiocytes, macrophages and components of the pathological extracellular matrix are major fibrogenic effectors and thus pharmacological targets for therapies aimed at inhibition of fibrosis progression or induction of fibrosis reversal. The advent of novel, highly sensitive and specific serum biomarkers and imaging methods to assess the dynamics of liver fibrosis in NASH will improve detection, stratification and follow-up of patients with progressive NASH . These non-invasive tools will also promote the clinical development of antifibrotic drugs, by permitting the design of lean proof-of-concept studies, and enabling development of a personalised antifibrotic therapy for patients with rapid fibrosis progression or advanced disease.

How to improve access to therapy in hepatitis B patients

Despite the availability of a preventive vaccine and active antiviral treatments that stop disease progression and reduce the risk of hepatocellular carcinoma, hepatitis B is still a major public health problem. Only an estimated 10% of the 257 million people living with HBV have been diagnosed and as few as 1% are being adequately treated. Barriers to diagnosis and treatment include: (i) limited awareness and lack of knowledge about HBV infection and HBV-related diseases; (ii) under-diagnosis with insufficient screening and referral to care; (iii) limited treatment due to drug availability, costs, reimbursement policies and the need for long-term or life-long therapy. These barriers and the actions needed to improve access to treatment are strongly influenced by the prevalence of infection and affect middle-high vs low-middle income countries differently, where most HBV carriers are found. In high-prevalence regions and low-to middle-income countries, the main challenges are availability and cost while in low-prevalence regions and middle-to high-income countries low screening rates, public awareness, social stigma and discrimination play an important role. Overcoming these challenges on a global scale is a complex clinical and public health challenge and multilateral commitment from pharmaceutical companies, governments, funders and the research community is lacking. The new WHO 2016 Global Health Sector Strategy on viral hepatitis targets testing and treatment, suggesting that important but strong actions are needed from advocacy groups, scientific societies and funding agencies to foster awareness and access to cure.

Risk factors for biopsy-proven advanced non-alcoholic fatty liver disease in the Veterans Health Administration

BACKGROUND

With its increasing incidence, nonalcoholic fatty liver disease (NAFLD) is of particular concern in the Veterans Health Administration (VHA).

AIMS

To evaluate risk factors for advanced fibrosis in biopsy-proven NAFLD in the VHA, to identify patients at risk for adverse outcomes.

METHODS

In randomly selected cases from VHA databases (2005-2015), we performed a retrospective case-control study in adults with biopsy-defined NAFLD or normal liver.

RESULTS

Of 2091 patients reviewed, 399 met inclusion criteria. Normal controls (n = 65) had normal liver function. The four NAFLD cohorts included: NAFL steatosis (n = 76), nonalcoholic steatohepatitis (NASH) without fibrosis (n = 68), NAFLD/NASH stage 1-3 fibrosis (n = 82), and NAFLD/NASH cirrhosis (n = 70). NAFLD with hepatocellular carcinoma (HCC) was separately identified (n = 38). Most patients were older White men. NAFLD patients with any fibrosis were on average severely obese (BMI>35 kg/m² ). Diabetes (54.4%-79.6%) and hypertension (85.8%-100%) were more common in NAFLD with fibrosis or HCC. Across NAFLD, 12.3%-19.5% were enrolled in diet/exercise programs and 0%-2.6% had bariatric surgery. Hispanics exhibited higher rates of NASH (20.6%), while Blacks had low NAFLD rates (1.4%-11.8%), particularly NAFLD cirrhosis and HCC (1.4%-2.6%). Diabetes (OR 11.8, P < .001) and BMI (OR 1.4, P < .001) were the most significant predictors of advanced fibrosis.

CONCLUSIONS

In the VHA, diabetes and severe obesity increased risk for advanced fibrosis in NAFLD. Of these patients, only a small proportion (~20%) had enrolled in diet/exercise programs or had bariatric surgery (~2%). These results suggest that providers should focus/tailor interventions to improve outcomes, particularly in those with diabetes and severe obesity.

Disabling portosystemic encephalopathy in a non-cirrhotic patient: Successful endovascular treatment of a giant inferior mesenteric-caval shunt via the left internal iliac vein

Hepatic encephalopathy is suspected in non-cirrhotic cases of encephalopathy because the symptoms are accompanied by hyperammonaemia. Some cases have been misdiagnosed as psychiatric diseases and consequently patients hospitalized in psychiatric institutions or geriatric facilities. Therefore, the importance of accurate diagnosis of this disease should be strongly emphasized. A 68-year-old female patient presented to the Emergency Room with confusion, lethargy, nausea and vomiting. Examination disclosed normal vital signs. Neurological examination revealed a minimally responsive woman without apparent focal deficits and normal reflexes. She had no history of hematologic disorders or alcohol abuse. Her brain TC did not demonstrate any intracranial abnormalities and electroencephalography did not reveal any subclinical epileptiform discharges. Her ammonia level was > 400 mg/dL (reference range < 75 mg/dL) while hepatitis viral markers were negative. The patient was started on lactulose, rifaximin and low-protein diet. On the basis of the doppler ultrasound and abdomen computed tomography angiography findings, the decision was made to attempt portal venography which confirmed the presence of a giant portal-systemic venous shunt. Therefore, mechanic obliteration of shunt by interventional radiology was performed. As a consequence, mesenteric venous blood returned to hepatopetally flow into the liver, metabolic detoxification of ammonia increased and hepatic encephalopathy subsided. It is crucial that physicians immediately recognize the presence of non-cirrhotic encephalopathy, in view of the potential therapeutic resolution after accurate diagnosis and appropriate treatments.

Imaging biomarkers in liver fibrosis

There is a need for early identification of patients with chronic liver diseases due to their increasing prevalence and morbidity-mortality. The degree of liver fibrosis determines the prognosis and therapeutic options in this population. Liver biopsy represents the reference standard for fibrosis staging. However, given its limitations and complications, different non-invasive methods have been developed recently for the in vivo quantification of fibrosis. Due to their precision and reliability, biomarkers' measurements derived from Ultrasound and Magnetic Resonance stand out. This article reviews the different acquisition techniques and image processing methods currently used in the evaluation of liver fibrosis, focusing on their diagnostic performance, applicability and clinical value. In order to properly interpret their results in the appropriate clinical context, it seems necessary to understand the techniques and their quality parameters, the standardization and validation of the measurement units and the quality control of the methodological problems.