Shear wave velocity is a useful marker for managing nonalcoholic steatohepatitis

Liver Ultrasound Elastography in Non-Alcoholic Fatty Liver Disease: A State-of-the-Art Summary

Non-alcoholic fatty liver disease (NAFLD) is a chronic disease which is currently the most common hepatic disorder affecting up to 38% of the general population with differences according to age, country, ethnicity and sex. Both genetic and acquired risk factors such as a high-calorie diet or high intake of saturated fats have been associated with obesity, diabetes and, finally, NAFLD. A liver biopsy has always been considered essential for the diagnosis of NAFLD; however, due to several limitations such as the potential occurrence of major complications, sampling variability and the poor repeatability in clinical practice, it is considered an imperfect option for the evaluation of liver fibrosis over time. For these reasons, a non-invasive assessment by serum biomarkers and the quantification of liver stiffness is becoming the new frontier in the management of patients with NAFLD and liver fibrosis. We present a state-of-the-art summary addressing the methods for the non-invasive evaluation of liver fibrosis in NAFLD patients, particularly the ultrasound-based techniques (transient elastography, ARFI techniques and strain elastography) and their optimal cut-off values for the staging of liver fibrosis.

Different Ultrasound Shear Wave Elastography Techniques as Novel Imaging-Based Approaches for Quantitative Evaluation of Hepatic Steatosis-Preliminary Findings

BACKGROUND

Modern ultrasound (US) shear-wave dispersion (SWD) and attenuation imaging (ATI) can be used to quantify changes in the viscosity and signal attenuation of the liver parenchyma, which are altered in hepatic steatosis. We aimed to evaluate modern shear-wave elastography (SWE), SWD and ATI for the assessment of hepatic steatosis.

METHODS

We retrospectively analyzed the US data of 15 patients who underwent liver USs and MRIs for the evaluation of parenchymal disease/liver lesions. The USs were performed using a multifrequency convex probe (1-8 MHz). The quantitative US measurements for the SWE (m/s/kPa), the SWD (kPa-m/s/kHz) and the ATI (dB/cm/MHz) were acquired after the mean value of five regions of interest (ROIs) was calculated. The liver MRI (3T) quantification of hepatic steatosis was performed by acquiring proton density fat fraction (PDFF) mapping sequences and placing five ROIs in artifact-free areas of the PDFF scan, measuring the fat-signal fraction. We correlated the SWE, SWD and ATI measurements to the PDFF results.

RESULTS

Three patients showed mild steatosis, one showed moderate steatosis and eleven showed no steatosis in the PDFF sequences. The calculated SWE cut-off (2.5 m/s, 20.4 kPa) value identified 3/4 of patients correctly (AUC = 0.73, p > 0.05). The SWD cut-off of 18.5 m/s/kHz, which had a significant correlation (r = 0.55, p = 0.034) with the PDFF results (AUC = 0.73), identified four patients correctly (p < 0.001). The ideal ATI (AUC = 0.53 (p < 0.05)) cut-off was 0.59 dB/cm/MHz, which showed a significantly good correlation with the PDFF results (p = 0.024).

CONCLUSION

Hepatic steatosis can be accurately detected using all the US-elastography techniques applied in this study, although the SWD and the SWE showed to be more sensitive than the PDFF.

Variability, Validity and Operator Reliability of Three Ultrasound Systems for Measuring Tissue Stiffness: A Phantom Study

Introduction

Ultrasound elastography is a method of measuring soft tissue stiffness to detect the presence of pathology. There are several ultrasound elastography devices on the market. The aim of this study was twofold. Firstly, to determine the validity of three different ultrasound systems used to measure tissue stiffness. Secondly, to determine the operator reliability and repeatability when using these three systems.

Materials and methods

Two observers undertook multiple stiffness measurements from a phantom model using three different ultrasound systems; the LOGIQ E9, the Aixplorer, and the Acuson S2000. The phantom model had four cylindrical-shaped inclusions (Type 1-4) of increasing stiffness values and diameter embedded within. The background phantom stiffness was fixed. The mean, standard deviation, and coefficient of variation (CV) were calculated from measured stiffness readings per diameter per inclusion. Intra-observer variability was assessed. The validity of the measured stiffness value was assessed by calculating the difference between the measured elasticities and actual phantom elasticities. Bland-Altman plots with limits of agreement were used to display the inter-observer agreement. The intraclass correlation coefficients (ICC) were used to measure intra-observer, inter-observer, and inter-system reliability.

Results

Each observer undertook 1020 measurements. All three systems generally underestimated the stiffness values for the inclusions; the higher the actual stiffness value, the more significant the underestimation. The percentage difference between measured stiffness and actual stiffness varied from -79.1% to 12.7%. The intra-observer variability was generally less than 5% for observers using the LOGIQ E9 and the Aixplorer systems but more than 10% over the stiffer inclusions (Types 3 and 4) for the Acuson system. There was 'almost perfect' intra-observer reliability and repeatability for both the LOGIQ E9 and the Aixplorer systems; this was 'moderate' for the Acuson system over specific inclusions. For all systems, there was 'almost perfect' inter-observer reliability and repeatability between Observer A and Observer B. The inter-system reliability and repeatability were 'almost perfect' between the LOGIQ E9 system and the Aixplorer system but 'poor' and 'moderate' when the Acuson system was matched with the LOGIQ E9 system and the Aixplorer system, respectively.

Conclusion

This study has demonstrated that the Acuson, LOGIQ E9, and Aixplorer ultrasound systems have low variability, high reproducibility, and good intra-observer and inter-observer reliability when used to measure tissue stiffness. However, they all underestimated the stiffness values during this in vitro study. This study also revealed that not all ultrasound systems are comparable when measuring tissue stiffness, with some having better inter-system reliability than others. Ongoing standardization of technology is required at the manufacturer level.

Current Techniques for the Objective Measures of Erectile Hardness

INTRODUCTION

One of the most discussed topics in the urology provider's office is that of the male penile erection. Moreover, this is also a frequent basis for consultation by primary care practitioners. As such, it is essential that urologists are familiar with the various means by which the male erection may be evaluated.

OBJECTIVES

This article describes several techniques presently available that may serve to objectively quantify the rigidity and hardness of the male erection. These techniques are meant to bolster information gathered from the patient interview and physical examination to better guide patient management.

METHODS

An extensive literature review was performed examining publications in PubMed on this subject, including corresponding contextual literature.

RESULTS

While validated patient questionnaires have been routinely employed, the urologist has many additional means available to uncover the extent of the patient's pathology. Many of these tools are noninvasive techniques that involve virtually no risk to the patient and take advantage of pre-existing physiologic properties of the phallus and its blood supply to estimate corresponding tissue stiffness. Specifically, Virtual Touch Tissue Quantification which precisely quantifies axial and radial rigidity, can provide continuous data on how these forces change over time, thus providing a promising comprehensive assessment.

CONCLUSION

Quantification of the erection allows for the patient and provider to assess response to therapy, aids the surgeon in choice of appropriate procedure, and guides effective patient counseling regarding expectation management. Rohrer GE, Premo H, Lentz AC. Current Techniques for the Objective Measures of Erectile Hardness. Sex Med Rev 2022;XX:XXX-XXX.

Gravity assistance enables liver stiffness measurements to detect liver fibrosis under congestive circumstances

BACKGROUND

As survival has been prolonged owing to surgical and medical improvements, liver failure has become a prognostic determinant in patients with congestive heart diseases. Congestive hepatopathy, an abnormal state of the liver as a result of congestion, insidiously proceed toward end-stage liver disease without effective biomarkers evaluating pathological progression. Regular measurements of shear wave elastography cannot qualify liver fibrosis, which is a prognosticator in any type of chronic liver disease, in cases of congestion because congestion makes the liver stiff without fibrosis. We hypothesized that the effects of congestion and fibrosis on liver stiffness can be dissociated by inducing architectural deformation of the liver to expose structural rigidity.

AIM

To establish a strategy measuring liver stiffness as a reflection of architectural rigidity under congestion.

METHODS

Two-dimensional shear wave elastography (2dSWE) was measured in the supine (Sp) and left decubitus (Ld) positions in 298 consecutive cases as they were subjected to an ultrasound study for various liver diseases. Regions of interest were placed at twelve sites, and the median and robust coefficient of variation were calculated. Numerical data were compared using the Mann-Whitney U or Kruskal-Wallis test followed by Dunn's post-hoc multiple comparisons. The inferior vena cava (IVC) diameters at different body positions were compared using the Wilcoxon matched pairs signed rank test. The number of cases with cardiothoracic ratios greater than or not greater than 50% was compared using Fisher's exact test. A correlation of 2dSWE between different body positions was evaluated by calculating Spearman correlation coefficients.

RESULTS

The IVC diameter was significantly reduced in Ld in subjects with higher 2dSWE values in Ld (LdSWE) than in Sp (SpSWE) (P = 0.007, (average ± SD) 13.9 ± 3.6 vs 13.1 ± 3.4 mm) but not in those with lower LdSWE values (P = 0.32, 13.3 ± 3.5 vs 13.0 ± 3.5 mm). In 81 subjects, SpSWE was increased or decreased in Ld beyond the magnitude of robust coefficient of variation, which suggests that body postural changes induced an alteration of liver stiffness significantly larger than the technical dispersion. Among these subjects, all 37 with normal SpSWE had a higher LdSWE than SpSWE (Normal-to-Hard, SpSWE - LdSWE (∆2dSWE): (minimum-maximum) -0.74 - -0.08 m/sec), whereas in 44 residual subjects with abnormal SpSWE, LdSWE was higher in 27 subjects (Hard-to-Hard, -0.74 - -0.05 m/sec) and lower in 17 subjects (Hard-to-Soft, 0.04 - 0.52 m/sec) than SpSWE. SpSWE was significantly correlated with ∆2dSWE only in Hard-to-Soft (P < 0.0001). ∆2dSWE was larger in each lobe than in the entire liver. When Hard-to-Hard and Hard-to-Soft values were examined for each lobe, fibrosis-4 or platelet counts were significantly higher or lower only for Hard-to-Soft vs Normal-to-Hard cases.

CONCLUSION

Gravity alters the hepatic architecture during body postural changes, causing outflow blockage in hepatic veins. A rigid liver is resistant to structural deformation. Stiff-liver softening in the Ld position suggests a fibrous liver.

Extrahepatic biliary obstruction can interfere with hepatic fibrosis prediction using two-dimensional shear wave elastography in dogs

Two-dimensional shear wave elastography (2D-SWE) can be used to quantitatively evaluate the elastic modulus of the liver as shear wave velocity (SWV), which can noninvasively predict clinically relevant hepatic fibrosis in both dogs and humans. However, extrahepatic biliary obstruction (EHBO), regardless of the presence of clinically relevant hepatic fibrosis, can influence SWVs in humans and thus may interfere with hepatic fibrosis prediction using 2D-SWE in dogs. The aim of this prospective, observational, and one-group pretest-posttest study is to investigate whether SWV measured by 2D-SWE displays a difference between dogs with and without EHBO. A total of 20 dogs were included (7 with EHBO and 13 with gallbladder pathology but no EHBO) that underwent preoperative SWV measurement using 2D-SWE. In all dogs, stages of hepatic fibrosis were evaluated histopathologically using a scoring scheme. In addition, postoperative SWVs in dogs with EHBO relieved via laparotomy were also evaluated. The median (range) SWVs in the dogs with and without EHBO were 1.91 (1.81-2.54) m/s and 1.57 (1.37-1.64) m/s, respectively. Although there was no significant difference in the histopathological hepatic fibrosis stages between the dogs with and without EHBO, the preoperative SWVs in the dogs with EHBO were significantly higher than in dogs without EHBO (P = .0004), and SWVs were found to decrease significantly after surgery (P = .0097). This study demonstrates that EHBO can increase the SWV of dogs without clinically relevant hepatic fibrosis and can interfere with the prediction of noninvasive hepatic fibrosis using 2D-SWE.

Diagnosis and Staging of Pediatric Non-Alcoholic Fatty Liver Disease: Is Classical Ultrasound the Answer?

The increased prevalence of non-alcoholic fatty liver disease (NAFLD) requires special attention in pediatric patients, as it manifests in them in a more severe and progressive way compared to adults. The implementation of the appropriate therapeutic interventions is determinant of the attempts to treat it. For that purpose, early diagnosis and staging of the disease is essential. The purpose of this review was to find and reveal the most appropriate diagnostic strategies and tools for diagnosis and staging of pediatric NAFLD/NASH based on their accuracy, safety and effectiveness. The methodology followed was that of the literature review. Particular emphasis was put on the recent bibliography. A comparative study of published articles about the diagnosis and management of pediatric NAFLD/NASH was also performed. In terms of diagnosis, the findings converged on the use of classical ultrasound. Ultrasound presented average sensitivity and specificity for diagnosing the disease in children, while in the adult population, sensitivity and specificity were significantly higher. Proton density fat fraction magnetic resonance imaging has been increasingly used for the diagnosis of steatosis in pediatric patients. Elastography is an effective tool for staging liver fibrosis and discriminating NASH from NAFLD in children. Even though liver biopsy is the gold standard, especially for NASH, it should be avoided for pediatric patients. Biochemical tests are less specific and less sensitive for the diagnosis of NAFLD, and some of them are of high cost. It seems that diagnostic imaging should be a first-line tool for the staging and monitoring pediatric NAFLD/NASH in order for appropriate interventions to be implanted in a timely way.

Multiparametric in vivo ultrasound shear wave viscoelastography on farm-raised fatty duck livers: human radiology imaging applied to food sciences

Nine mulard ducks that were being raised for foie gras (steatosis) production went through in vivo shear wave (SW) elastography imaging of their liver during the force-feeding period to investigate changes in liver tissue characteristics. A total of 4 imaging sessions at an interval of 3 to 4 d were conducted at the farm on each animal. Three ducks were sacrificed at the second, third, and fourth imaging sessions for histopathology analysis of all animals at these time points. Six SW elastography parameters were evaluated: SW speed, SW attenuation, SW dispersion, Young's modulus, viscosity, and shear modulus. Shear waves of different frequencies propagate with different phase velocities. Thus, SW speed and other dependent parameters such as Young's modulus, viscosity, and shear modulus were computed at 2 frequencies: 75 and 202 Hz. Each parameter depicted a statistically significant trend along the force-feeding process (P-values between 0.001 and 0.0001). The fat fraction of the liver increased over the 12-day period of feeding. All parameters increased monotonically over time at 75 Hz, whereas modal relations were seen at 202 Hz. Shear wave dispersion measured between 75 and 202 Hz depicted a plateau from day 5. Based on this validation, proposed imaging methods are aimed to be used in the future on naturally fed ducks and geese.

Clinical assessment and management of liver fibrosis in non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is among the most frequent etiologies of cirrhosis worldwide, and it is associated with features of metabolic syndrome; the key factor influencing its prognosis is the progression of liver fibrosis. This review aimed to propose a practical and stepwise approach to the evaluation and management of liver fibrosis in patients with NAFLD, analyzing the currently available literature. In the assessment of NAFLD patients, it is important to identify clinical, genetic, and environmental determinants of fibrosis development and its progression. To properly detect fibrosis, it is important to take into account the available methods and their supporting scientific evidence to guide the approach and the sequential selection of the best available biochemical scores, followed by a complementary imaging study (transient elastography, magnetic resonance elastography or acoustic radiation force impulse) and finally a liver biopsy, when needed. To help with the selection of the most appropriate method a Fagan′s nomogram analysis is provided in this review, describing the diagnostic yield of each method and their post-test probability of detecting liver fibrosis. Finally, treatment should always include diet and exercise, as well as controlling the components of the metabolic syndrome, +/- vitamin E, considering the presence of sleep apnea, and when available, allocate those patients with advanced fibrosis or high risk of progression into clinical trials. The final end of this approach should be to establish an opportune diagnosis and treatment of liver fibrosis in patients with NAFLD, aiming to decrease/stop its progression and improve their prognosis.

Screening and follow-up of chronic liver diseases with understanding their etiology in clinics and hospitals

BACKGROUND AND AIM

Considering the increasing prevalence of non-alcoholic fatty liver disease and non-alcoholic steatohepatitis (NASH), the development of an effective screening and follow-up system that enables the recognition of etiological changes by primary physicians in clinics and specialists in hospitals is required.

METHODS

Chronic hepatitis B (HBV) and C (HCV), NASH, and alcoholic steatohepatitis (ASH) patients who were assayed for Mac-2-binding protein glycosylation isomer (M2BPGi) (n = 272) and underwent magnetic resonance elastography (MRE) (n = 119) were enrolled. Patients who underwent MRE were also tested by ultrasound elastography (USE) (n = 80) and for M2BPGi (n = 97), autotaxin (ATX) (n = 62), and platelet count (n = 119), and their fibrosis-4 (FIB-4) index was calculated (n = 119).

RESULTS

FIB-4 index >2, excluding HBV-infected patients, M2BPGi >0.5, ATX >0.5, and platelet count <20 × 104/μL were the benchmark indices, and we took into consideration other risk factors, such as diabetes mellitus and age, to recommend further examinations, such as USE, based on the local situation to avoid overlooking hepatocellular carcinoma (HCC) in the clinic. During specialty care in the hospital, MRE exhibited high diagnostic ability for fibrosis stages >F3 or F4; it could efficiently predict collateral circulation with high sensitivity, which can replace USE. We also identified etiological features and found that collateral circulation in NASH/ASH patients tended to exceed high-risk levels; moreover, these patients exhibited more variation in HCC-associated liver stiffness than the HBV and HCV patients.

CONCLUSIONS

Using appropriate markers and tools, we can establish a stepwise, practical, noninvasive, and etiology-based screening and follow-up system in primary and specialty care.

Hepatocellular Carcinoma and Non-Alcoholic Fatty Liver Disease: A Step Forward for Better Evaluation Using Ultrasound Elastography

Simple Summary

Non-alcoholic fatty liver disease (NAFLD) attracts a lot of attention, due to the increasing prevalence and progression to fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). Consequently, new non-invasive, cost-effective diagnostic methods are needed. This review aims to explore the diagnostic performance of ultrasound (US) elastography in NAFLD and NAFLD-related HCC, adding a new dimension to the conventional US examination—the liver stiffness quantification. The vibration controlled transient elastography (VCTE), and 2D-Shear wave elastography (2D-SWE) are effective in staging liver fibrosis in NAFLD. VCTE presents the upside of assessing steatosis through the controlled attenuation parameter. Hereby, we critically reviewed the elastography techniques for the quantitative characterization of focal liver lesions (FLLs), focusing on HCC: Point shear wave elastography and 2D-SWE. 2D-SWE presents a great potential to differentiate malignant from benign FLLs, guiding the clinician towards the next diagnostic steps. As a disease-specific surveillance tool, US elastography presents prognostic capability, improving the NAFLD-related HCC monitoring.

Abstract

The increasing prevalence of non-alcoholic fatty liver disease (NAFLD) in the general population prompts for a quick response from physicians. As NAFLD can progress to liver fibrosis, cirrhosis, and even hepatocellular carcinoma (HCC), new non-invasive, rapid, cost-effective diagnostic methods are needed. In this review, we explore the diagnostic performance of ultrasound elastography for non-invasive assessment of NAFLD and NAFLD-related HCC. Elastography provides a new dimension to the conventional ultrasound examination, by adding the liver stiffness quantification in the diagnostic algorithm. Whilst the most efficient elastographic techniques in staging liver fibrosis in NAFLD are vibration controlled transient elastography (VCTE) and 2D-Shear wave elastography (2D-SWE), VCTE presents the upside of assessing steatosis through the controlled attenuation parameter (CAP). Hereby, we have also critically reviewed the most important elastographic techniques for the quantitative characterization of focal liver lesions (FLLs), focusing on HCC: Point shear wave elastography (pSWE) and 2D-SWE. As our paper shows, elastography should not be considered as a substitute for FLL biopsy because of the stiffness values overlap. Furthermore, by using non-invasive, disease-specific surveillance tools, such as US elastography, a subset of the non-cirrhotic NAFLD patients at risk for developing HCC can be detected early, leading to a better outcome. A recent ultrasomics study exemplified the wide potential of 2D-SWE to differentiate benign FLLs from malignant ones, guiding the clinician towards the next steps of diagnosis and contributing to better long-term disease surveillance.

Diagnostic Accuracy of Shear Wave Elastography as a Non-invasive Biomarker of High-Risk Non-alcoholic Steatohepatitis in Patients with Non-alcoholic Fatty Liver Disease

In this study, we evaluated the diagnostic accuracy of shear wave elastography (SWE) for differentiating high-risk non-alcoholic steatohepatitis (hrNASH) from non-alcoholic fatty liver and low-risk non-alcoholic steatohepatitis (NASH). Patients with non-alcoholic fatty liver disease scheduled for liver biopsy underwent pre-biopsy SWE. Ten SWE measurements were obtained. Biopsy samples were reviewed using the NASH Clinical Research Network Scoring System and patients with hrNASH were identified. Receiver operating characteristic curves for SWE-based hrNASH diagnosis were charted. One hundred sixteen adult patients underwent liver biopsy at our institution for the evaluation of non-alcoholic fatty liver disease. The area under the receiver operating characteristic curve of SWE for hrNASH diagnosis was 0.73 (95% confidence interval: 0.61-0.84, p < 0.001). The Youden index-based optimal stiffness cutoff value for hrNASH diagnosis was calculated as 8.4 kPa (1.67 m/s), with a sensitivity of 77% and specificity of 66%. SWE may be useful for the detection of NASH patients at risk of long-term liver-specific morbidity and mortality.

The diagnostic accuracy of liver fibrosis in non-viral liver diseases using acoustic radiation force impulse elastography: A systematic review and meta-analysis

BACKGROUND

Acoustic radiation force impulse (ARFI) imaging is an ultrasound-based elastography method that has been studied in the staging of hepatic fibrosis, especially in chronic hepatitis. However, the diagnostic accuracy of ARFI in non-viral hepatopathies, such as autoimmune hepatitis and non-alcoholic fatty liver disease, has not been systematically determined.

AIM

To systematically assess the diagnostic accuracy of ARFI in non-viral hepatopathies.

METHODS

The databases of PubMed, Embase, Cochrane Library and clinicaltrials.gov were systematically searched for candidate studies reporting the diagnostic accuracy of ARFI for hepatic fibrosis. The pooled estimates of the sensitivity, specificity, diagnostic odds ratio, and positive and negative likelihood ratios were calculated with the summary receiver operating curve (sROC) performed using STATA software.

RESULTS

In detail, a total of 29 diagnostic studies were included for further analysis. The quality of the included studies was relatively high using QUADAS method. The pooled sensitivity and specificity were 0.79 (0.73, 0.83) and 0.81 (0.75, 0.86), with AUROC 0.87 (0.83, 0.89) for the staging of significant fibrosis (F≥2). Meanwhile, for the staging of severe fibrosis (F≥3), the pooled sensitivity and specificity were 0.92 (0.87, 0.95) and 0.85 (0.80, 0.89), with AUROC 0.94 (0.92, 0.96). Furthermore, the pooled sensitivity and specificity were 0.89 (0.79, 0.95) and 0.89 (0.85, 0.92), with AUROC 0.94 (0.92, 0.96) for ARFI in staging cirrhosis (F = 4), which were similar to the data for severe fibrosis. No significant publication bias was present in this study.

CONCLUSION

This meta-analysis demonstrated that ARFI exerted satisfactory diagnostic performance in staging non-viral hepatic fibrosis, especially severe fibrosis (F≥3) and cirrhosis (F = 4).

Acoustic Radiation Force Impulse and Conventional Ultrasound in the Prediction of Cirrhosis Complicating Fatty Liver: Does Body Mass Index Independently Alter the Results?

We investigated whether ultrasound (US) could quantify steatosis and fibrosis in non-alcoholic fatty liver disease (NAFLD). Estimates of fat by gray-scale, hepatorenal index (HRI) and fibrosis by acoustic radiation force impulse (ARFI) were made using the interquartile range (IQR)/median for ARFI quality. Biopsy was the gold standard. US fat assessment correlated with histologic grade and predicted steatosis. HRI predicted steatosis but did not improve accuracy. ARFI of good quality was highly sensitive toward severe fibrosis. The median ARFI value depended linearly on body mass index (BMI). Poor quality ARFI data had higher histologic steatosis, leading to higher mean steatosis grades in rejected data (p = 0.018). The ARFI quality cut with IQR/median >0.15 or >0.3 excluded many more patients with severe steatosis versus normal, influenced by increasing BMI. By combining the baseline US with ARFI, patients can be concurrently diagnosed for steatosis and fibrosis, two of the key pathologies of NAFLD and non-alcoholic steatohepatitis (NASH). However, severe steatosis and high BMI may falsely alter ARFI results.

Usefulness of noninvasive shear wave elastography for the assessment of hepatic fibrosis in dogs with hepatic disease

BACKGROUND

Two-dimensional shear wave elastography (2D-SWE) can noninvasively evaluate hepatic elastic modulus as shear wave velocity (SWV). Additionally, it may predict the presence of clinical relevant hepatic fibrosis (≥F2) in dogs with hepatic disease.

OBJECTIVES

To investigate whether SWV measured by 2D-SWE can differentiate between dogs with (≥F2) and without (F0-1) clinically relevant hepatic fibrosis.

ANIMALS

Twenty-eight client-owned dogs with hepatic disease and 8 normal healthy Beagle dogs were enrolled.

METHODS

In this cross-sectional prospective study, SWVs were measured using 2D-SWE in all dogs. Hepatic fibrosis stages and necroinflammatory activity grades were histopathologically evaluated using a histological scoring scheme that was adapted from the Ishak schema used in human medicine.

RESULTS

Median SWVs were significantly higher in dogs with clinically relevant hepatic fibrosis (2.04 m/s; range, 1.81-2.26 m/s) than in healthy dogs (1.51 m/s; range, 1.44-1.66 m/s; P = .007), and dogs without clinically relevant hepatic fibrosis (1.56 m/s; range, 1.37-1.67 m/s; P < .001). However, no significant difference was found in the SWVs between dogs without clinically relevant hepatic fibrosis and healthy dogs (P = .99). Furthermore, median SWVs were not significantly different among dogs with necroinflammatory activity, those without necroinflammatory activity, and healthy dogs (Kruskal-Wallis test, P = .12).

CONCLUSIONS AND CLINICAL IMPORTANCE

The 2D-SWE may be useful for predicting the presence of hepatic fibrosis in dogs with hepatic disease.

The clinical usefulness of elastography in the evaluation of nonalcoholic fatty liver disease patients: A biopsy-controlled study

BACKGROUND

We aimed at determination of the usefulness of elastography [acoustic radiation force impulse (ARFI) and FibroScan] for evaluation of nonalcoholic fatty liver disease (NAFLD) patients.

PATIENTS AND METHODS

A prospective cross-sectional study included 60 biopsy-proven NAFLD patients (mean age: 45 years) was carried out. All patients were subjected to lab works, liver biopsy, and measurement of liver stiffness by ARFI and FibroScan and steatosis by controlled attenuation parameter (CAP). CAP measurements were adjusted for the presence of NAFLD and presence or absence of diabetes and according to BMI.

RESULTS

Linear regression analysis showed that CAP is an independent predictor for significant hepatic steatosis (P<0.001). No significant difference was found in diagnostic accuracy between adjusted and nonadjusted CAP values for diagnosis of mild (>S1) or significant (>S2) hepatic steatosis (P=0.17 and 0.29 respectively). The median ARFI velocities for F1, F2, F3, and F4 were 0.92, 1.08, 1.07, and 2.58 m/s, respectively. Although there was an overall significant increase in ARFI values across the fibrosis grades (P<0.04), the difference in ARFI values was only significant between fibrosis grades F1 and F4 (P=0.02).

CONCLUSION

Elastography is a promising noninvasive tool for diagnosis and grading of hepatic steatosis and fibrosis in patients with NAFLD/nonalcoholic steatohepatitis with good sensitivity and specificity, especially in moderate to marked grades.

Rational arrangement of measuring shear wave speed in the liver

BACKGROUND

Shear wave speed has been widely applied to quantify a degree of liver fibrosis. However, there is no standardized procedure, which makes it difficult to utilize the speed universally.

AIM

To provide procedural standardization of shear wave speed measurement.

METHODS

Point shear wave elastography (pSWE) was measured in 781 patients, and two-dimensional shear wave elastography (2dSWE) was measured on the same day in 18 cases. Regions-of-interest were placed at 12 sites, and the median and robust coefficient-of-variation (CVR) were calculated. A residual sum-of-square (Σdi²) was computed for bootstrap values of 1000 iterations in 18 cases with each assumption of 1 to 12 measurements. The proportion of the Σdi² (%Σdi²) was calculated as the ratio of Σdi² to pSWE after converting it based on the correlation between pSWE and 2dSWE.

RESULTS

The CVR showed a significantly broader distribution in the left lobe (P < 0.0001), and the smallest CVR in the right anterior segment that covered 95% cases was 40.4%. pSWE was significantly higher in the left lobe than in the right lobe (1.63 ± 0.78 m/s vs 1.61 ± 0.78 m/s, P = 0.0004), and the difference between the lobes became further discrete when the subjects were limited to the cases with a CVR less than 40.4% in any segment (1.76 ± 0.80 m/s vs 1.70 ± 0.82 m/s, P < 0.0001). The highest values of the CVR in every 0.1 m/s interval were plotted in convex upward along pSWE and peaked at 1.93 m/s. pSWE and 2dSWE were significantly correlated (P < 0.0001, r = 0.95). In 216000 resamples from 18 cases, the %Σdi² of 12 sites was 8.0% and gradually increased as the acquisition sites decreased to reach a significant difference with a %Σdi² of 7 sites (P = 0.027).

CONCLUSION

These data suggest that shear wave speed should be measured at 8 or more sites of spreading in both lobes.

Evaluation of liver and spleen stiffness of healthy dogs by use of two-dimensional shear wave elastography

OBJECTIVE

To assess liver and spleen stiffness in healthy dogs by use of a novel 2-D shear wave elastography (SWE) technique and to investigate the repeatability and reproducibility of the technique.

ANIMALS

8 healthy adult Beagles.

PROCEDURES

2-D SWE was performed on each dog to assess liver and spleen stiffness. Repeatability (intraday variability) and reproducibility (interday variability) of 2-D SWE were investigated. For all 8 dogs, 2-D SWE was performed 3 times in 1 day (4-hour intervals) and on 3 separate days (1-week interval). Data were expressed as mean ± SD values for shear wave velocity and the Young modulus in the liver and spleen. Intraday and interday coefficients of variation were assessed for all variables.

RESULTS

Mean ± SD shear wave velocity obtained for the liver and spleen was 1.51 ± 0.08 m/s and 2.18 ± 0.27 m/s, respectively. Mean value for the Young modulus obtained for the liver and spleen was 6.93 ± 0.79 kPa and 14.66 ± 3.79 kPa, respectively. Elasticity values were significantly higher for the spleen than for the liver. Intraday and interday coefficients of variation for all variables were < 25% (range, 3.90% to 20.70%).

CONCLUSIONS AND CLINICAL RELEVANCE

2-D SWE was a feasible technique for assessing liver and spleen stiffness of healthy dogs. Future studies on the application of 2-D SWE for dogs with chronic hepatitis, cirrhosis, and portal hypertension are needed to evaluate the clinical applicability of 2-D SWE.

A cut-off value of shear wave speed to distinguish nonalcoholic steatohepatitis candidates

To distinguish and characterize nonalcoholic steatohepatitis (NASH) candidates from among medical checkup visitor diagnosed with nonalcoholic fatty liver diseases (mcNAFLDs).A cut-off value has not been established to differentiate NASH at the earliest stage in NAFLD.Shear wave speed (SWS) was measured in the livers of 480 mcNAFLDs. NASH candidates were screened out by adopting a statistically defined cut-off value of SWS and were characterized in terms of food preference.SWS ranged between 1.11 and 2.18 m/s and fit a Gaussian distribution (r = 0.98) with an average and SD of 1.324 and 0.0847 m/s, respectively, in 320/160 males/females 64.4 (interquartile range 57.3-69.4) years old. The average plus SD (1.41 m/s) screened out 82 (17.1%) NASH candidates, who were significantly older (66.8 vs. 64.1 years old, P = 0.001) and had higher fibrosis 4 index values (1.58 vs. 1.33, P < 0.0001) than the remaining mcNAFLDs. The number of patients with a BMI greater than 25 kg/m was 118 (29.6%) mcNAFLDs and 34 (41.5%) NASH candidates, with a significantly higher frequency in NASH candidates (P = 0.05). Obese patients preferentially ate fatty acids in general, while NASH candidates preferred to consume several long-chain unsaturated fatty acids irrespective of their BMI.These results suggest that NASH candidates who have a longer disease duration and pathological progression can be distinguished from mcNAFLDs by a statistically defined cut-off value of SWS. The defined value indicates that there are different food habitats associated with obesity and NAFLD progression.

A cut-off value of shear wave speed to distinguish nonalcoholic steatohepatitis candidates

To distinguish and characterize nonalcoholic steatohepatitis (NASH) candidates from among medical checkup visitor diagnosed with nonalcoholic fatty liver diseases (mcNAFLDs).A cut-off value has not been established to differentiate NASH at the earliest stage in NAFLD.Shear wave speed (SWS) was measured in the livers of 480 mcNAFLDs. NASH candidates were screened out by adopting a statistically defined cut-off value of SWS and were characterized in terms of food preference.SWS ranged between 1.11 and 2.18 m/s and fit a Gaussian distribution (r = 0.98) with an average and SD of 1.324 and 0.0847 m/s, respectively, in 320/160 males/females 64.4 (interquartile range 57.3-69.4) years old. The average plus SD (1.41 m/s) screened out 82 (17.1%) NASH candidates, who were significantly older (66.8 vs. 64.1 years old, P = 0.001) and had higher fibrosis 4 index values (1.58 vs. 1.33, P < 0.0001) than the remaining mcNAFLDs. The number of patients with a BMI greater than 25 kg/m was 118 (29.6%) mcNAFLDs and 34 (41.5%) NASH candidates, with a significantly higher frequency in NASH candidates (P = 0.05). Obese patients preferentially ate fatty acids in general, while NASH candidates preferred to consume several long-chain unsaturated fatty acids irrespective of their BMI.These results suggest that NASH candidates who have a longer disease duration and pathological progression can be distinguished from mcNAFLDs by a statistically defined cut-off value of SWS. The defined value indicates that there are different food habitats associated with obesity and NAFLD progression.

Liver Ultrasound Elastography: An Update to the World Federation for Ultrasound in Medicine and Biology Guidelines and Recommendations

The World Federation for Ultrasound in Medicine and Biology has produced these guidelines for the use of elastography techniques in liver diseases. For each available technique, the reproducibility, results and limitations are analyzed, and recommendations are given. This set of guidelines updates the first version, published in 2015. Since the prior guidelines, there have been several advances in technology. The recommendations are based on the international published literature, and the strength of each recommendation is judged according to the Oxford Centre for Evidence-Based Medicine. The document has a clinical perspective and is aimed at assessing the usefulness of elastography in the management of liver diseases.

Diagnostic accuracy of point shear wave elastography and transient elastography for staging hepatic fibrosis in patients with non-alcoholic fatty liver disease: a meta-analysis

OBJECTIVE

This study aimed to assess the accuracy of staging liver fibrosis in patients with non-alcoholic fatty liver disease (NAFLD) usingpoint shear wave elastography (pSWE) and transient elastography (TE).

SETTING

Relevant records on NAFLD were retrieved from PubMed, Embase, Web of Science and the China National Knowledge Infrastructure databases up to 20 December 2017. A bivariate mixed-effects model was conducted to combine sensitivity, specificity, positive likelihood ratio, negative likelihood ratio and area under the summary receiver operating characteristic curve (AUC) between pSWE and TE. A sensitivity analysis was implemented to explore the source of heterogeneity.

PARTICIPANTS

Patients with NAFLD who had a liver stiffness measurement using pSWE and TE before liver biopsy were enrolled according to the following criteria: 2×2 contingency tables can be calculated via the reported number of cases; sensitivity and specificity were excluded according to the following criteria: history of other hepatic damage, such as chronic hepatitis C, concurrent active hepatitis B infection, autoimmune hepatitis, suspicious drug usage and alcohol abuse.

RESULTS

Nine pSWE studies comprising a total of 982 patients and 11 TE studies comprising a total of 1753 patients were included. For detection of significant fibrosis, advanced fibrosis and cirrhosis, the summary AUC was 0.86 (95% CI 0.83 to 0.89), 0.94 (95% CI 0.91 to 0.95) and 0.95 (95% CI 0.93 to 0.97) for pSWE, and the summary AUC was 0.85 (95% CI 0.82 to 0.88), 0.92 (95% CI 0.89 to 0.94) and 0.94 (95% CI 0.93 to 0.97) for TE, respectively. The proportion of failure measurement was over tenfold as common with TE using an M probe compared with pSWE.

CONCLUSION

pSWE and TE, providing precise non-invasive staging of liver fibrosis in NAFLD, are promising techniques, particularly for advanced fibrosis and cirrhosis.

Clinical strategy of diagnosing and following patients with nonalcoholic fatty liver disease based on invasive and noninvasive methods

Nonalcoholic fatty liver disease (NAFLD) is an important cause of chronic liver injury in many countries. The incidence of NAFLD is rising rapidly in both adults and children, because of the currently ongoing epidemics of obesity and type 2 diabetes. Notably, histological liver fibrosis is recognized as the main predictive factor for the overall long-term outcome of NAFLD, including cardiovascular disease and liver-related mortality. Thus, staging of liver fibrosis is essential in determining the prognosis and optimal treatment for patients with NAFLD and in guiding surveillance for the development of hepatocellular carcinoma (HCC). Whereas liver biopsy remains the gold standard for staging liver fibrosis, it is impossible to enforce liver biopsy in all patients with NAFLD. Noninvasive biological markers, scoring systems and noninvasive modalities are increasingly being developed and investigated to evaluate fibrosis stage of NAFLD patients. This review will highlight recent studies on the diagnosis and staging of NAFLD based on invasive (liver biopsy) or noninvasive (biomarker, scoring systems, US-based elastography and MR elastography) methods.

Role of Point Shear Wave Elastography in the Determination of the Severity of Fibrosis in Pediatric Liver Diseases With Pathologic Correlations

OBJECTIVES

Our aims in this study were as follows: (1) to determine the cutoff value that can distinguish between advanced liver fibrosis and normal liver tissue for two different elastographic techniques; (2) to determine the cutoff value that can distinguish mild liver fibrosis from normal liver tissue for the techniques; and (3) to assess tissue stiffness in nonalcoholic fatty liver disease (NAFLD).

METHODS

Seventy-five patients assessed for liver biopsy on the same day were evaluated by point shear wave elastography. Thirty-one healthy children and 11 children with NAFLD were also evaluated. A 9L4 transducer with Virtual Touch quantification (VTQ) and Virtual Touch imaging and quantification (VTIQ) modes (Siemens Medical Solutions, Mountain View, CA) was used for quantification.

RESULTS

The shear wave speed of the patients with NAFLD was higher than that of the control group. The only predictive factor for VTQ and VTIQ was the histologic fibrosis score (model-adjusted R²  = 0.56 for VTQ and 0.75 for VTIQ). Shear wave speed cutoffs were 1.67 m/s for VTQ and 1.56 m/s for VTIQ in detecting fibrosis or inflammation and 2.09 m/s for VTQ and 2.17 m/s for VTIQ in discriminating children with low and high histologic liver fibrosis scores.

CONCLUSIONS

The VTQ and VTIQ values reveal high-grade histopathologic fibrosis and have high success rates when distinguishing high- from low-grade fibrosis. However, they have limited success rates when differentiating low-grade fibrosis from normal liver tissue.

Ultrasound shear wave elastography and liver fibrosis: A Prospective Multicenter Study

AIM

To assess the accuracy of shear wave elastography (SWE) alone and in combination with aminotransferase platelet ratio index (APRI) score in the staging of liver fibrosis.

METHODS

A multicenter prospective study was conducted to assess the accuracy of SWE (medians) and APRI to predict biopsy results. The analysis focused on distinguishing the different stages of liver disease, namely, F0 from F1-4, F0-1 from F2-4, F0-2 from F3-4 and F0-3 from F4; F0-F1 from F2-F4 being of primary interest. The area under the receiver operating characteristic (AUROC) curve was computed using logistic regression model. The role of age, gender and steatosis was also assessed.

RESULTS

SWE alone accurately distinguished F0-1 from F2-4 with a high probability. The AUROC using SWE alone was 0.91 compared to 0.78 for using the APRI score alone. The APRI score, when used in conjunction with SWE, did not make a significant contribution to the AUROC. SWE and steatosis were the only significant predictors that differentiated F0-1 from F2-4 with an AUROC of 0.944.

CONCLUSION

Our study validates the use of SWE in the diagnosis and staging of liver fibrosis. Furthermore, the probability of a correct diagnosis is significantly enhanced with the addition of steatosis as a prognostic factor.

Diagnostic Accuracy of Acoustic Radiation Force Impulse (ARFI) in Diagnosis of Liver Fibrosis among Egyptian Patients with Chronic HCV Infection

BACKGROUND:

Acoustic radiation force impulse (ARFI) evaluates liver stiffness non-invasively and was invented recently. This technique can easily and accurately assess the degree of liver fibrosis in clinical practice.

AIM:

The aim of this study was to detect the diagnostic performance of ARFI elastography in the staging of fibrosis in some Egyptian patients with chronic HCV infection.

PATIENTS AND METHODS:

One hundred ninety patients with chronic HCV infection; 142 men and 48 women were enrolled in the study. They underwent liver biopsy examination for liver fibrosis detection. All demographic; clinical and biochemical data were recoded. ARFI examination was done for all subjects to detect liver stiffness measurement in relation to liver fibrosis detected by pathological examination of liver biopsies.

RESULTS:

Medians of liver stiffness measurement by shear wave velocity showed a significant increase as a grade of liver fibrosis increases (p ≤ 0.0001, highly significant). Liver stiffness was directly correlated to age, AST; ALT; INR and liver steatosis (p values were: 0.009; 0.0001; 0.013; 0.006 and 0.04 respectively, significant). On the other hand, liver stiffness was inversely correlated to albumin; prothrombin concentration and platelets (p values were: 0.0001; 0.001, and 0.0001, respectively, significant). We found that shear wave velocity can predict F1; F2; F3 and F4 at cut-off values: 1.22; 1.32; 1.44 and 1.8 respectively.

CONCLUSION:

ARFI is a diagnostic noninvasive promising technique for liver fibrosis diagnosis among Egyptian patients with chronic HCV infection.

ACOUSTIC RADIATION FORCE IMPULSE IS EQUIVALENT TO LIVER BIOPSY TO EVALUATE LIVER FIBROSIS IN PATIENTS WITH CHRONIC HEPATITIS C AND NONALCOHOLIC FATTY LIVER DISEASE

BACKGROUND

Liver biopsy is recommended as the gold standard method for assessing the stage of liver fibrosis in patients with chronic liver disease. However, it is invasive, with potential risks and complications. Elastography is an ultrasound technique that provides information of changes in the liver tissue, evaluating tissue elasticity and acoustic radiation force impulse is one of the available techniques.

OBJECTIVE

The main objective of this study was to evaluate the sensitivity and specificity of acoustic radiation force impulse comparing to liver biopsy to evaluate fibrosis in patients with chronic hepatitis C virus and nonalcoholic fatty liver disease.

METHODS

Twenty four patients were included, everyone underwent liver biopsy and acoustic radiation force impulse, and the results were compared with values described in the literature by several authors.

RESULTS

In the population of patients with chronic hepatitis C, our data were better correlated with data published by Carmen Fierbinteanu-Braticevici et al., with an accuracy of 82.4%, sensitivity of 71.4% and specificity of 90%. For nonalcoholic fatty liver disease, our data were better correlated with data published by Masato Yoneda et al., with an accuracy of 85.7%, sensitivity 80% and specificity of 100%.

CONCLUSION

Acoustic radiation force impulse is a method with good accuracy to distinguish initial fibrosis from advanced fibrosis in hepatitis C virus and nonalcoholic fatty liver disease and can replace biopsy in most cases.

Relationship between liver tissue stiffness and histopathological findings analyzed by shear wave elastography and compression testing in rats with non-alcoholic steatohepatitis

PURPOSE

The aim of the present study was to investigate two methods of determining liver stiffness in rats with various degrees of non-alcoholic steatohepatitis induced by a methionine- and choline-deficient (MCD) diet by comparing each finding with reference to histopathological liver findings.

METHODS

Twenty male Wister rats were fed an MCD diet for up to 32 weeks, and four were fed a normal diet. Ultrasound-based shear wave elastography (SWE) and mechanical compression testing using an Instron Universal Testing machine were performed on each rat at designated time points. After each examination, liver histopathology was analyzed to evaluate the degrees of steatosis, inflammation, and fibrosis based on non-alcoholic fatty liver disease (NAFLD) activity score, and each finding was compared with reference to liver histopathologic findings.

RESULTS

Median liver stiffness values measured using SWE showed a stepwise increase with increasing histological inflammation score (P = 0.002), hepatic fibrosis stage (P = 0.029), ballooning score (P = 0.012), and steatosis grade (P = 0.030). Median liver stiffness measured using an Instron machine showed a stepwise increase only with increasing histological fibrosis stage (P = 0.033).

CONCLUSIONS

Degree of liver stiffness measured by SWE and the Instron machine differed. SWE reflected mainly inflammation, whereas Instron machine-derived values primarily reflected fibrosis. This is the main source of discrepancies between measurements made with these two modalities.

Formulation for Effective Screening and Management of Nonalcoholic Steatohepatitis: Noninvasive NAFLD Management Strategy

To establish a versatile means for screening and management of nonalcoholic steatohepatitis (NASH), shear wave velocity was measured in 20 normal controls and 138 consecutive nonalcoholic fatty liver disease (NAFLD) cases. Referencing biochemical properties in 679 healthy volunteers, a formula to distinguish NASH suspects was established and validated in another cohort of 138 histologically proven NAFLD cases. NASH and simple steatosis (SS) suspects were selected based on a plot of shear wave velocity against age. A formula consisting of five factors (γ-glutamyl transpeptidase, alkaline phosphatase, platelet counts, body mass index, and presence/absence of type 2 diabetes mellitus) distinguished NASH suspects from SS suspects with area under the receiver operating characteristic curve values of 86% and 84% in the development and validation cohorts. Among 25 NAFLD cases in which shear wave velocity was repeatedly measured, 8 and 9 cases revealed an increase or decrease, respectively, of shear wave velocity in the entire liver, and the corresponding change in shear wave velocity was primarily observed in the right lobe or the left lateral segment, respectively. These results suggest that the new formula and sequential shear wave velocity measurements at each segment enable high throughput screening of NASH suspects and noninvasive assessment of pathophysiological alleviation/aggravation in cases of NASH.

Feasibility study for assessing liver fibrosis in paediatric and adolescent patients using real-time shear wave elastography

INTRODUCTION

The objective of this study was to evaluate the feasibility of shear wave elastography (SWE), as a non-invasive means of assessing liver fibrosis stage in paediatric and adolescent patients.

MATERIALS AND METHODS

Consecutive paediatric and adolescent subjects scheduled for liver biopsy (LB) evaluation of known or suspected diffuse liver disease were included after informed guardian consent and subject assent in this IRB-approved single institution study. Elastograms were acquired prior to liver biopsy, from the liver under a breath-hold after normal inspiration when possible. Biopsy specimens underwent blinded pathologist review using the METAVIR scoring system.

RESULTS

Twenty-four patients (M : F = 13:11) with a mean age of 17 years (range: 1-21 years) underwent liver biopsy. The distribution of fibrosis on pathological examination was: F0 = 10, F1 = 9, F2 = 1, F3 = 3, and F4 = 1. Subjects with stages F0 and F1 fibrosis had a mean SWE value of 6.93 kPa (95% CI: 6.33-7.44 kPa) and 8.33 kPa (95% CI: 6.83-10.80 kPa) respectively. The SWE value for the one subject with stage F2 fibrosis was 6.36 kPa, whereas for F3 and F4 were 8.86 (95% CI: 5.70-11.40) and 17.85 kPa respectively. The correlation between SWE values and fibrosis grade was strong (r = 0.58, P = 0.003), and the area under the ROC curve differentiatiang ≥F2 fibrosis was 0.62 (95% CI: 0.26-0.98).

CONCLUSION

Estimation of liver stiffness using real-time SWE is feasible using the SC6-1 ultrasound probe in paediatric and adolescent patients and strongly correlates with the stage of fibrosis.

Hyaluronic acid as a non-invasive biomarker of liver fibrosis

Chronic liver diseases may cause inflammation and progressive scarring, over time leading to irreversible hepatic damage (cirrhosis). As a result, the need to assess and closely monitor individuals for risk factors of components of matrix deposition and degradation, as well as the severity of the fibrosis using biomarkers, has been increasingly recognized.

AIM

Our aim is to review the use of biomarker for diagnosing and defining the severity of liver fibrosis.

METHODS

A systematic literature review was done using the terms "hyaluronic acid" and "liver fibrosis" as well as the name of each biomarker or algorithm known to be employed. PubMed and Google Scholar were searched, and English language articles indexed between January 2010 and October 2014 in which HA was used as a marker of liver fibrosis were retrieved, regardless of the underlying liver disease. Each author read the publications separately and the results were analyzed and discussed.

RESULTS

Biomarkers offer a potential prognostic or diagnostic indicator for disease manifestation, progression, or both. Serum biomarkers, including HA, have been used for many years. Emerging biomarkers such as metalloproteinases have been proposed as tools that provide valuable complementary information to that obtained from traditional biomarkers. Moreover, markers of extracellular matrix degradation provide powerful predictions of risk. In order for biomarkers to be clinically useful in accurately diagnosing and treating disorders, age-specific reference intervals that account for differences in gender and ethnic origin are a necessity.

CONCLUSIONS

This review attempts to provide a comprehensive analysis of the emerging risk biomarkers of liver fibrosis and to describe the clinical significance and analytical considerations of each biomarker pointing out sentinel features of disease progression.

Acoustic Radiation Force Impulse Elastography for the Non-Invasive Evaluation of Hepatic Fibrosis in Non-Alcoholic Fatty Liver Disease Patients: A Systematic Review & Meta-Analysis

Background

In order to better monitor non-alcoholic fatty liver disease (NAFLD) patients at higher risk for HCC, there is a need for non-invasive diagnostic approaches to screen for the presence of advanced fibrosis in these patients. The aim of this systematic review and meta-analysis will be to evaluate the diagnostic efficacy of ARFI elastography in detecting hepatic fibrosis in NAFLD patients.

Methods

Relevant studies were identified from systematic searches of several major electronic databases (PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials). The primary outcomes were the summary sensitivity, summary specificity, the diagnostic odds ratio, and the summary receiver operating characteristic curve (SROC) of ARFI elastography in detecting significant fibrosis (defined as 4>F≥2) in NAFLD patients. Study quality was assessed using the Quality Assessment of Studies of Diagnostic Accuracy included in Systematic Review (QUADAS-2).

Results

The summary sensitivity and specificity of ARFI in detecting significant fibrosis were 80.2% (95% confidence interval (CI): 0.758–0.842; p = 0.0000) and 85.2% (95% CI: 0.808–0.890), p = 0.1617), respectively. The pooled diagnostic odds ratio of ARFI in detecting significant fibrosis was 30.13 (95% CI: 12.08–75; chi-squared = 14.59, p = 0.0237). The area under the SROC curve (AUC) was 0.898 (standard error (SE): 0.031) with a Q* index of 0.830 (SE: 0.033).

Conclusions

ARFI elastography appears to be modestly accurate in detecting significant fibrosis in NAFLD patients. Future studies in this field should provide head-to-head comparisons of ARFI elastography versus other elastographic imaging modalities in NAFLD patients.

WFUMB guidelines and recommendations for clinical use of ultrasound elastography: Part 3: liver

The World Federation for Ultrasound in Medicine and Biology (WFUMB) has produced these guidelines for the use of elastography techniques in liver disease. For each available technique, the reproducibility, results, and limitations are analyzed, and recommendations are given. Finally, recommendations based on the international literature and the findings of the WFUMB expert group are established as answers to common questions. The document has a clinical perspective and is aimed at assessing the usefulness of elastography in the management of liver diseases.

Role of ultrasound in the diagnosis and treatment of nonalcoholic fatty liver disease and its complications

We review the role of liver ultrasonography (US) and related techniques as non-invasive tools in predicting metabolic derangements, liver histology, portal hypertension and cardiovascular risk as well as allowing early diagnosis and management of hepatocellular carcinoma in patients with nonalcoholic fatty liver disease. In this setting, US detects fatty changes as low as ≥20% and hepatic steatosis identified ultrasonographically, in its turn, closely mirrors coronary and carotid atherosclerosis burden. Semi-quantitative US indices (to exclude nonalcoholic steatohepatitis) and sonoelastography (to quantify fibrosis) help in predicting liver histology and selecting patients to submit to liver biopsy. Surveillance for hepatocellular carcinoma conducted through biannual US is mandatory and US has a role in guiding locoregional treatment and in evaluating the efficacy of treatment. High-intensity focused ultrasound can be delivered with precision resulting in coagulative necrosis of hepatocellular carcinoma without puncturing the liver. Costs and inconveniences have so far hampered its diffusion.

Non-invasive Testing for NASH and NASH with Advanced Fibrosis: Are We There Yet?

Nonalcoholic fatty liver disease (NAFLD) is the most prevalent etiology of chronic liver disease in America. NAFLD can be broadly classified in two subtypes: nonalcoholic fatty liver (NAFL), which is generally considered a benign condition with negligible risk of progression to cirrhosis, and nonalcoholic steatohepatitis (NASH), which is generally considered to be progressive with substantial risk of progression to cirrhosis. Additionally, recent studies suggest the odds of liver mortality increases amongst NASH patients with advanced fibrosis (bridging fibrosis ± cirrhosis). Liver biopsy examination is the current gold standard to accurately discriminate between NAFL vs. NASH as well as diagnose advanced fibrosis. However, due to its invasive nature, risk of bleeding (and even rarely death), prohibitive cost, and sampling error, liver biopsies are imperfect for diagnosis and monitoring of NAFLD. As a result, noninvasive biomarkers that can accurately detect NASH and advanced fibrosis without biopsy are needed. This article will discuss the most novel noninvasive biomarkers in diagnosing NASH and advanced fibrosis.

Preliminary study on the kidney elasticity quantification in patients with chronic kidney disease using virtual touch tissue quantification

Background:

Virtual touch tissue quantification (VTTQ) provides numerical measurements (shear wave velocity (SWV) values) of tissue stiffness.

Objectives:

The purpose of this study was to describe the SWV values of the kidney by VTTQ and to examine the clinical usefulness of this procedure in the evaluation of elasticity changes in the kidneys of patients with chronic kidney disease (CKD).

Patients and Methods:

Sixty-five patients with CKD and seventy healthy participants were included in this study. A total of 270 kidneys were examined by VTTQ. The kidney elasticity was expressed as shear wave velocity. The SWV values, blood serum creatinine (Scr)/BUN and pathological findings were analyzed and compared between patients with CKD and healthy participants.

Results:

In patients with CKD and healthy participants, the SWV values both gradually decreased from the renal cortex to the medulla and renal sinus The SWV value of the renal cortex in patients with CKD was less than that of healthy participants (P < 0.05), and the SWV value of the renal cortex in patients with renal insufficiency was significantly less than in those with normal renal function (2.46 ± 0.15 vs. 3.45 ± 0.26 m/s, P < 0.05). The best cutoff value for predicting renal insufficiency (Scr > 1.24 mg/dL or/and BUN > 21 mg/DL) was a SWV value of the renal cortex of less than 1.92 m/s with a sensitivity of 84.4% (95% CI: 67.2-94.7%) and a specificity of 96.8% (95% CI: 83.3-99.9%) (P < 0.001).

Conclusion:

VTTQ can sensitively detect the elasticity changes in patients with CKD, and it can effectively predict renal insufficiency. This technology provides a valuable tool for the assessment of CKD.

Usefulness of evaluating hepatic elasticity using artificial acoustic radiation force ultrasonography before hepatectomy

AIM

To evaluate hepatic fibrosis and tumor diagnosis preoperatively, we investigated the elasticity calculated by the new parameter of ultrasonography, acoustic radiation force impulse (ARFI).

METHODS

We examined ARFI of the non-tumorous right and left lateral liver and in the tumor by push pulse of probe in 95 patients with hepatic malignancies undergoing hepatectomy. Measurement of ARFI as hepatic stiffness was indicated as the Vs (m/s).

RESULTS

Measuring the Vs in the non-tumor region was achieved in the right liver in 99% and at the left lateral liver in 94%. The Vs in the right liver was significantly lower than in the left lateral liver, and the Vs of the liver tumor was significantly higher than in the non-tumorous liver. The Vs in the right and left lateral liver was correlated with the platelet count, aspartate aminotransferase, fibrotic indices and indocyanine green test. The Vs in the right liver was significantly correlated with the fibrotic marker or index. The Vs of liver cirrhosis and histological stage 4 in the right and left liver was significantly the highest compared to the others. The Vs in the right liver showed a high area under the receiver-operator curve value predicting histological fibrosis. The Vs in the right was significantly correlated with blood loss and postoperative complications, particularly uncontrolled ascites.

CONCLUSION

Non-invasive ARFI imaging elastography is useful in evaluating impaired liver function or in the differential diagnosis of liver malignancies, highly hepatic fibrosis and in predicting posthepatectomy morbidity.

The frequency and determinants of liver stiffness measurement failure: a retrospective study of "real-life" 38,464 examinations

Objective

To investigate the frequency and determinants of liver stiffness measurement (LSM) failure by means of FibroScan in “real-life” Chinese patients.

Methods

A total of 38,464 “real-life” Chinese patients in 302 military hospital of China through the whole year of 2013, including asymptomatic carrier, chronic hepatitis B, chronic hepatitis C, liver cirrhosis (LC), alcoholic liver disease, autoimmune liver disease, hepatocellular carcinoma (HCC) and other, were enrolled, their clinical and biological parameters were retrospectively investigated. Liver fibrosis was evaluated by FibroScan detection. S probe (for children with height less than 1.20 m) and M probe (for adults) were used. LSM failure defined as zero valid shots (unsuccessful LSM), or the ratio of the interquartile range to the median of 10 measurements (IQR/M) greater than 0.30 plus median LSM greater or equal to 7.1 kPa (unreliable LSM).

Results

LSM failure occurred in 3.34% of all examinations (1286 patients out of 38,464), among them, there were 958 cases (2.49%) with unsuccessful LSM, and 328 patients (0.85%) with unreliable LSM. Statistical analyses showed that LSM failure was independently associated with body mass index (BMI) greater than 30 kg/m², female sex, age greater than 50 years, intercostal spaces (IS) less than 9 mm, decompensated liver cirrhosis and HCC patients. There were no significant differences among other diseases. By changing another skilled operator, success was achieved on 301 cases out of 1286, which reduced the failure rate to 2.56%, the decrease was significant (P<0.0001).

Conclusions

The principal reasons of LSM failure are ascites, obesity and narrow of IS. The failure rates of HCC, decompensated LC, elder or female patients are higher. These results emphasize the need for adequate operator training, technological improvements and optimal criteria for specific patient subpopulations.

Value of shear wave velocity measurements for the risk assessment of hepatocellular carcinoma development in patients with nonalcoholic fatty liver disease : HCC risk assessment by VTTQ

PURPOSE

To evaluate the value of measuring shear wave velocity evoked by acoustic radiation force impulse (VTTQ) for the risk assessment of hepatocellular carcinoma (HCC) development in patients with nonalcoholic fatty liver disease (NAFLD).

METHODS

VTTQ was measured three times in each of the four liver segments in 163 NAFLD patients, including 14 HCC cases; the results were statistically evaluated.

RESULTS

The VTTQ was 3.04 ± 0.17 m/s (median ± median absolute deviation) and 1.27 ± 0.25 m/s in patients with and without HCC, respectively, and was significantly higher in HCC cases (p < 0.001). When the patients were classified as F0-F4 based on VTTQ cutoff values, VTTQ was significantly higher in the left lobe than in the right lobe for F0 (p < 0.0001) and for F1 and F2 combined (p < 0.0001), but not significantly higher for F3 and F4 combined (p = 0.070). The robust coefficient of variation was significantly higher in the left than in the right (p = 0.018) and significantly increased as VTTQ increased (p = 0.0002). Multivariate analysis showed that total bilirubin concentration {p = 0.014, 38.9 (2.08-727) [odds ratio (95 % confidence interval)]} and VTTQ [p = 0.006, 113 (3.91-3245)] were the only independent explanatory factors for HCC presence among the seven variables identified by univariate analysis. The area under the receiver-operating characteristic curve in the differentiation of HCC from non-HCC was 0.943 for VTTQ and was comparable to that for other noninvasive markers such as Fib-4 (0.964) or higher than that in BARD (0.838).

CONCLUSIONS

These results suggest that fibrosis occurs heterogeneously throughout the liver and that VTTQ measurements are useful in HCC risk evaluation in a NAFLD cohort.

Systematic review with meta-analysis: non-invasive assessment of non-alcoholic fatty liver disease--the role of transient elastography and plasma cytokeratin-18 fragments

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) affects 15-40% of the general population. Some patients have non-alcoholic steatohepatitis (NASH) and progressive fibrosis, and would be candidates for monitoring and treatment.

AIM

To review current literature on the use of non-invasive tests to assess the severity of NAFLD.

METHODS

Systematic literature searching identified studies evaluating non-invasive tests of NASH and fibrosis using liver biopsy as the reference standard. Meta-analysis was performed for areas with adequate number of publications.

RESULTS

Serum tests and physical measurements like transient elastography (TE) have high negative predictive value (NPV) in excluding advanced fibrosis in NAFLD patients. The NAFLD fibrosis score comprises of six routine clinical parameters and has been endorsed by current American guidelines as a screening test to exclude low-risk individuals. The pooled sensitivities and specificities for TE to diagnose F ≥ 2, F ≥ 3 and F4 disease were 79% and 75%, 85% and 85%, and 92% and 92% respectively. Liver stiffness measurement often fails in obese patients, but the success rate can be improved with the use of the XL probe. A number of biomarkers have been developed for the diagnosis of NASH, but few were independently validated. Serum/plasma cytokeratin-18 fragments have been most extensively evaluated and have a pooled sensitivity of 66% and specificity of 82% in diagnosing NASH.

CONCLUSIONS

Current non-invasive tests are accurate in excluding advanced fibrosis in NAFLD patients, and may be used for initial assessment. Further development and evaluation of NASH biomarkers are needed.

Ultra-high frame rate tissue Doppler imaging

We describe a new tissue Doppler imaging (TDI) method, ultra-high frame rate tissue Doppler imaging (UFR-TDI). With two broad transmit beams covering only the ventricular walls, we achieve 1200 frames/s in a four-chamber apical view. We examined 10 healthy volunteers to study the feasibility of this method. Ultra-high-frame-rate TDI provided peak annular velocities and time to peak S' intervals in good agreement with those measured with conventional TDI. Moreover, UFR-TDI provided additional information in early and late systole: In all subjects, the method was able to separate the timing of electrical activation, start of mechanical contraction, mitral valve closure and start of ejection. The earliest mechanical activation was seen before mitral valve closure. The method was also able to measure the propagation speed of the mechanical wave created by aortic valve closure.

Increased hepatic stiffness as consequence of high hepatic afterload in the Fontan circulation: a vascular Doppler and elastography study

Hepatic dysfunction is a recognized complication after Fontan palliation of congenital heart disease. We sought to quantitatively measure hepatic stiffness and vascular Doppler indices using ultrasound (US) and shear wave elastography (SWE) in a Fontan cohort. Subjects were prospectively recruited for echocardiography and real-time hepatic duplex US with SWE for hepatic stiffness (kPa). Doppler peak velocities, velocity time integral, resistive, pulsatility, acceleration indices (RI, PI, AI), and flow volume were measured in celiac artery, superior mesenteric artery, and main portal vein (MPV). A subset underwent cardiac catheterizations with liver biopsy. Correlations were explored between SWE, duplex, hemodynamic, and histopathologic data. In all, 106 subjects were studied including 41 patients with Fontan physiology (age 13.8 ± 6 years, weight 45.4 ± 23 kg) and 65 controls (age 15.0 ± 8.4 years, weight 47.9 ± 22 kg). Patients with Fontan physiology had significantly higher hepatic stiffness (15.6 versus 5.5 kPa, P < 0.0001), higher celiac RI (0.78 versus 0.73, P = 0.04) superior mesenteric artery RI (0.89 versus 0.84, P = 0.005), and celiac PI (1.87 versus 1.6, P = 0.034); while MPV flow volume (287 versus 420 mL/min in controls, P = 0.007) and SMA AI (829 versus 1100, P = 0.002) were lower. Significant correlation was seen for stiffness with ventricular end-diastolic pressure (P = 0.001) and pulmonary artery wedge pressure (P = 0.009). Greater stiffness correlated with greater degrees of histopathologic fibrosis. No significant change was seen in stiffness or other duplex indices with age, gender, time since Fontan, or ventricular morphology.

CONCLUSION

Elevated hepatic afterload in Fontan, manifested by high ventricular end-diastolic pressures and pulmonary arterial wedge pressures, is associated with remarkably increased hepatic stiffness, abnormal vascular flow patterns, and fibrotic histologic changes. The MPV is dilated and carries decreased flow volume, while the celiac and superior mesenteric arterial RI is increased. SWE is feasible in this population and shows promise as a means for predicting disease severity on liver biopsy.

Quantitative assessment of the elasticity values of liver with shear wave ultrasonographic elastography

BACKGROUND & OBJECTIVES

Tissue stiffness in liver is related to tissue composition, which is changed by cirrhosis, hepatocellular carcinoma or metastases. Shear wave ultrasonographic elastography is a new imaging technique by which the elasticity of soft tissue can be measured quantitatively. The aim of this study was to measure the elasticity values of liver segments in healthy volunteers.

METHODS

One hundred twenty seven healthy volunteers (89 women, 38 men; mean age 37, 72 ± 9.11 yr, range 17-63 yr) were examined on shear wave elastography and ultrasonography by using convex probe with a frequency of 3 MHz. Individuals with liver hepatosteatosis, cirrhosis, chronic liver disease, or focal liver lesions were excluded from the study.

RESULTS

The mean elasticity values of right posterior, right anterior, left medial and left lateral segments of the liver was determined as 4 (±2.2), 3.3 (±2.1), 3.8 (±2.1), and 3.7 (±1.9) kPa for each segments, respectively. There was no significant difference in liver elasticity values between men and women.

INTERPRETATION & CONCLUSIONS

In this preliminary study the elasticity values of liver segments were measured by shear wave ultrasonographic elastography in normal healthy volunteers. Further studies, comparing elasticity values of normal and pathologic tissues are needed to detect the diagnostic role of this new technique.

Value of acoustic radiation force impulse imaging elastography for non-invasive evaluation of patients with nonalcoholic fatty liver disease

The goals of the work described here were to evaluate the clinical utility of acoustic radiation force impulse (ARFI) elastography in differentiating non-alcoholic fatty liver disease (NAFLD) histologic subtypes and to determine if ARFI elastography measurements correlate with the severity of liver fibrosis. We compared ARFI elastography measurements with clinical, biologic and histologic features (simple steatosis or steatohepatitis) in 64 patients with histologically proven NAFLD. ARFI elastography is suitable for distinguishing patients with non-alcoholic steatohepatitis from those with simple steatosis, with an area under the receiver operating characteristic curve (AUROC) of 0.867 (95% confidence interval = 0.782-0.953). There was a highly significant correlation (r = 0.843) between ARFI elastography measurements and fibrosis (p < 0.001). In patients with non-alcoholic steatohepatitis, the diagnostic performance of ARFI elastography in predicting significant fibrosis (F ≥ 2) had an AUROC of 0.944. ARFI elastography better predicted F = 4 fibrosis (AUROC = 0.984). In conclusion, ARFI elastography is a promising method for differentiating patients with non-alcoholic steatohepatitis from patients with simple steatosis and can also predict significant fibrosis in these patients.

Quantitative assessment of the elasticity values of liver with shear wave ultrasonographic elastography

BACKGROUND & OBJECTIVES

Tissue stiffness in liver is related to tissue composition, which is changed by cirrhosis, hepatocellular carcinoma or metastases. Shear wave ultrasonographic elastography is a new imaging technique by which the elasticity of soft tissue can be measured quantitatively. The aim of this study was to measure the elasticity values of liver segments in healthy volunteers.

METHODS

One hundred twenty seven healthy volunteers (89 women, 38 men; mean age 37, 72 ± 9.11 yr, range 17-63 yr) were examined on shear wave elastography and ultrasonography by using convex probe with a frequency of 3 MHz. Individuals with liver hepatosteatosis, cirrhosis, chronic liver disease, or focal liver lesions were excluded from the study.

RESULTS

The mean elasticity values of right posterior, right anterior, left medial and left lateral segments of the liver was determined as 4 (±2.2), 3.3 (±2.1), 3.8 (±2.1), and 3.7 (±1.9) kPa for each segments, respectively. There was no significant difference in liver elasticity values between men and women.

INTERPRETATION & CONCLUSIONS

In this preliminary study the elasticity values of liver segments were measured by shear wave ultrasonographic elastography in normal healthy volunteers. Further studies, comparing elasticity values of normal and pathologic tissues are needed to detect the diagnostic role of this new technique.

Evaluation of cervical cancer detection with acoustic radiation force impulse ultrasound imaging

The aim of this study was to evaluate the application of acoustic radiation force impulse (ARFI) ultrasound imaging and its potential value in the characterization of cervical cancer. ARFI ultrasound imaging of the uterine cervix was performed in 58 patients with cervical cancer prior to surgery. The diagnosis of cervical cancer was confirmed by pathological results in each case. eSie Touch elastography imaging (EI), Virtual Touch tissue imaging (VTI) and Virtual Touch tissue quantification (VTQ; Siemens Medical Solutions, Mountain View, CA, USA) were used to qualitatively and quantitatively analyze the elasticity and hardness of lesions. For statistical analysis, the non-parametric Mann-Whitney U test and the Student’s u test were used to compare the elastic parameters and the results. EI showed that, compared with the surrounding cervical tissue, 72.41% (42 of 58) of the malignant lesions showed 4th or 5th grade images and 27.59% (16 of 58) had 3rd grade images. The EI images showed a significant difference between the malignant lesions and the surrounding normal tissues (P<0.001). VTI showed that compared with the surrounding cervical tissue, 84.48% (49 of 58) of the malignant lesions were stiffer than the surrounding tissues and 15.52% (9 of 58) had black and white honeycomb-like images. The VTI images showed a significant difference between the malignant lesions and normal cervical tissues (P<0.001). The surrounding normal tissues had lower VTQ values, with a mean of 2.11±1.19 m/sec, while the VTQ values in malignant lesions were higher than the surrounding normal tissues (3.41±1.59 m/sec, P<0.001). ARFI ultrasound imaging of the uterine cervix may be an objective method for the assessment of soft tissues. It has high sensitivity and specificity in the evaluation of cervical cancer and therefore has good diagnostic value in clinical applications.