Which are the cut-off values of 2D-Shear Wave Elastography (2D-SWE) liver stiffness measurements predicting different stages of liver fibrosis, considering Transient Elastography (TE) as the reference method?

Liver Elastography Methods for Diagnosis of De Novo and Recurrent Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC), a common consequence of chronic liver disease, ranks among the most prevalent cancers globally and contributes significantly to cancer-related mortality. Liver fibrosis is intimately associated with hepatic function and the likelihood of future HCC occurrence. Despite the fact that liver biopsy continues to be the gold standard for diagnosing fibrosis, its utility is hindered by cost and invasiveness, along with patient unease, procedural rejection, and potential adverse effects. Liver elastography has become a leading noninvasive means of assessing tissue stiffness with considerable diagnostic precision. Malignant tumors generally exhibit higher cellularity in comparison to benign ones, resulting in increased stiffness. Elastography techniques capitalize on alterations in tissue elasticity stemming from specific pathological or physiological processes. Technological innovations, such as advanced ultrasound imaging and artificial intelligence (AI)-integrated systems, are paving the way for enhanced diagnostic accuracy and risk prediction. Recent research underscores the potential of elastography in managing HCC patients, presenting novel clinical applications, including prediction of HCC development, differentiation between malignant and benign liver lesions, evaluating treatment response, and forecasting recurrence post-treatment, though certain findings remain contentious. Therefore, this review aims to sum up the latest advancements in liver elastography for HCC patients, outlining its applications while addressing existing limitations and avenues for future progress.

Associations Between Multiparametric US-Based Indicators and Pathological Status in Patients with Metabolic Associated Fatty Liver Disease

OBJECTIVE

Noninvasive evaluation of metabolic dysfunction-associated fatty liver disease (MAFLD) using ultrasonography holds significant clinical value. The associations between ultrasound (US)-based parameters and the pathological spectra remain unclear and controversial. This study aims to investigate the associations thoroughly.

METHODS

The participants with MAFLD undergoing liver biopsy and multiparametric ultrasonography were prospectively recruited from December 2020 to September 2022. Three US-based parameters, namely attenuation coefficient (AC), liver stiffness (LS) and dispersion slope (DS) were obtained. The relationship between these parameters and steatosis grades, inflammation grades and fibrosis stages was examined.

RESULTS

In this study with 116 participants, AC values significantly differed across distinct steatosis grades (p < 0.001), while DS and LS values varied among inflammation grades (p < 0.001) and fibrosis stages (p < 0.001). The area under the receiver operating characteristic curves (AUCs) of AC ranged from 0.82 to 0.84 for differentiating steatosis grades, while AUCs of LS ranged from 0.62 to 0.76 for distinguishing inflammation grades and 0.83-0.95 for discerning fibrosis stages. AUCs for DS ranged from 0.79 to 0.81 in discriminating inflammation grades and 0.80-0.88 for differentiating fibrosis stages. Subgroup analysis revealed that LS demonstrated different trends in inflammation grade but consistent trends in fibrosis stage across subgroups, whereas DS showed consistent trends for both inflammation grade and fibrosis stage across all subgroups.

CONCLUSION

AC values indicate the degree of hepatic steatosis but not inflammation or fibrosis. LS values are determined only by fibrosis stage and are not associated with inflammation grades. DS values are associated with both fibrosis and inflammation grades.

Palm-Sized Wireless Transient Elastography System with Real-Time B-Mode Ultrasound Imaging Guidance: Toward Point-of-Care Liver Fibrosis Assessment

Transient elastography (TE), recommended by the WHO, is an established method for characterizing liver fibrosis via liver stiffness measurement (LSM). However, technical barriers remain towards point-of-care application, as conventional TE requires wired connections, possesses a bulky size, and lacks adequate imaging guidance for precise liver localization. In this work, we report the design, phantom validation, and clinical evaluation of a palm-sized TE system that enables simultaneous B-mode imaging and LSM. The performance of this system was validated experimentally using tissue-equivalent reference phantoms (1.45-75 kPa). Comparative studies against other liver elastography techniques, including conventional TE and two-dimensional shear wave elastography (2D-SWE), were performed to evaluate its reliability and validity in adults with various chronic liver diseases. Intra- and inter-operator reliability of LSM were established by an elastography expert and a novice. A good agreement was observed between the Young's modulus reported by the phantom manufacturer and this system (bias: 1.1-8.6%). Among 121 patients, liver stiffness measured by this system and conventional TE were highly correlated (r = 0.975) and strongly agreed with each other (mean difference: -0.77 kPa). Inter-correlation of this system with conventional TE and 2D-SWE was observed. Excellent-to-good operator reliability was demonstrated in 60 patients (ICCs: 0.824-0.913). We demonstrated the feasibility of employing a fully integrated phased array probe for reliable and valid LSM, guided by real-time B-mode imaging of liver anatomy. This system represents the first technical advancement toward point-of-care liver fibrosis assessment. Its small footprint, along with B-mode guidance capability, improves examination efficiency and scales up screening for liver fibrosis.

Assessment of hepatic fibrosis, portal hemodynamic changes, and disease severity in patients with HCV-related liver cirrhosis after sustained virologic response to direct-acting antiviral drugs (DAAs)

Background

Regression of fibrosis and improvement of portal hemodynamics after achievement of sustained viral response (SVR) in patients with chronic hepatitis C (HCV) is a subject of debate in different studies. Some studies reported improvement in the degree of fibrosis, while others did not find significant changes.

Objective

We aimed to evaluate changes in liver fibrosis, portal hemodynamics and clinical outcomes in patients with chronic HCV-related liver cirrhosis after the achievement of SVR with direct-acting antiviral drugs (DAAs).

Patients and methods

In our prospective longitudinal study, a total of 100 patients with chronic HCV infection-related liver cirrhosis were recruited, received DAAs, and completed the follow-up period. Clinical evaluation for assessment of liver disease severity using MELD and Child–Pugh class and scores were done. A noninvasive assessment of liver fibrosis using serum biomarkers (APRI index & FIB4 score) and share wave elastography (SWE) was done. Portal hemodynamic evaluation using Doppler ultrasound was done. All were done at baseline and 3 and 12 months after the end of therapy.

Results

A significant reduction in the degree of fibrosis was observed. Share wave elastography (SWE) readings showed 19.79% and 30.45% reduction 3 and 12 months after the end of therapy respectively (P < 0.001). Regarding the FIB4 score, the percentage of score reduction was 19.8% and 26.46% 3 and 12 months after the end of therapy, respectively (P < 0.01). APRI scores showed 22.6% and 41.09% reduction 3 and 12 months after the end of therapy respectively (P < 0.001). Significant improvement in Child–Pugh scores 3 and 12 months after the end of treatment was observed. Doppler ultrasound showed a significant increase in portal vein flow velocity, a significant decrease in time average mean velocity, and cross-section area 12 months after the end of treatment.

Conclusion

There was a considerable degree of reduction of liver fibrosis, improvement of portal hemodynamics, and Child–Pugh score in cirrhotic HCV patients who achieved SVR after DAAs.

Trial registration

ClinicalTrials.gov, ID: NCT03241823. Registered on 08 May 2017.

Application of Supersonic Shear Imaging to the Baveno VI Criteria and a Combination Model with Spleen Stiffness Measurement to Rule Out High-Risk Varices in Compensated Advanced Chronic Liver Disease

PURPOSE

Recently, Colecchia et al. reported that by adding a spleen stiffness (SS) criterion sequentially to the Baveno VI criteria, screening endoscopy could be safely avoided. We aimed to compare the Baveno VI criteria, SS values and a sequential combination of the Baveno VI and SS values, measured by supersonic shear imaging (SSI), as approaches for safely avoiding screening endoscopy for high-risk varices (HRV).

MATERIALS AND METHODS

Between April 2017 and July 2018, we enrolled 274 compensated advanced chronic liver disease patients who had successfully undergone liver stiffness (LS) and SS measurements with SSI and esophagogastroduodenoscopy (EGD). 52 HRV patients were included, and we analyzed risk factors for HRV and compared proportions of patients who were spared EGD when Baveno VI criteria, SS cut-off and the combination of the two approaches were used.

RESULTS

The AUROC values for estimating HRV by platelet count, LS and SS were 0.701, 0.757 and 0.844, respectively, and all three measures were found to be independent predictors of HRV. The SS cut-off value for excluding HRV was ≤ 27.3 kPa. The percentages of patients spared EGD were 18.6 % for Baveno VI, 28.8 % for SS cut-off and 36.1 % for the sequential combination of Baveno VI and SS cut-off. Less than 2 % of HRV patients were missed when using all of the criteria.

CONCLUSION

The Baveno VI criteria can be applied to LS measurement by SSI. SS measurement by SSI is an excellent predictor of HRV. Screening endoscopy can be safely avoided when Baveno VI criteria and SS cut-off are applied together.

Liver Ultrasound Attenuation: An Ultrasound Attenuation Index for Liver Steatosis Assessment

OBJECTIVES

Nonalcoholic fatty liver disease (NAFLD) is the most widespread chronic liver disease type in the Western countries. Ultrasound (US) is used for NAFLD and hepatic steatosis (HS) grading. The most popular US method for NAFLD assessment is the hepatorenal index (HRI), but because of its limitations, other noninvasive methods have been developed. The Resona 7 US system has recently incorporated an US attenuation-related quantitative feature, liver ultrasound attenuation (LiSA), for HS estimation. The purpose of this study is to compare LiSA's and HRI's performance on NAFLD assessment.

METHODS

A total of 159 NAFLD patients having a magnetic resonance imaging-proton density fat fraction (MRI-PDFF) examination were examined by 2 radiologists, who performed LiSA and HRI measurements in the liver. Correlation of LiSA's and HRI's measurements with MRI-PDFF values was calculated through Pearson correlation coefficient (PCC). To further investigate the performance of LiSA and HRI, optimum cutoffs, provided by the literature, were used to correspond HS grades to MRI-PDFF results. Moreover, a receiver operating characteristic (ROC) analysis on LiSA measurements and steatosis grades was performed.

RESULTS

Magnetic resonance imaging-PDFF was better correlated with LiSA (PCC = 0.80) than HRI (PCC = 0.67). Receiver operating characteristic analysis showed better performance range for LiSA (77.8%-91.8%) than for HRI (72.8%-85.4%) on all HS grades for all studies used for corresponding MRI-PDFF values to HS grades.

CONCLUSIONS

The results indicate that LiSA is more accurate than HRI in HS differentiation and can lead to more accurate grading of HS on NAFLD patients.

Liver Stiffness Is Markedly Decreased After Chronic Hepatitis C Treatment

AIM

The aim of the study was to demonstrate the liver stiffness (LS) change in chronic hepatitis C (CHC) patients obtained by elastography point quantification technique in before and after antiviral treatment (AVT).

MATERIAL AND METHODS

This prospective study included 84 patients diagnosed with CHC who had not previously received treatment for CHC and who had an indication for using direct-acting AVT. Necessary measurements were recorded with noninvasive liver fibrosis (LF) examinations. Posttreatment control of patients was carried out (ombitasvir + paritaprevir + ritonavir) + 3 months after the start of treatment for those treated with dasabuvir and 6 months after the start of treatment for patients treated with sofosbuvir + ribavirin. Liver stiffness changed after AVT is accepted as (Δ-LS), LS before AVT-LS after AVT.

RESULTS

Basal LS was found to decrease significantly after AVT (8.00 ± 2.56 kPa vs 6.95 ± 2.86 kPa, P < 0.05). Similar aspartate aminotransferase-to-platelet ratio index and platelet number fibrosis 4 indices were observed before and after AVT (P > 0.05). It was observed that Δ-LS value after AVT was lower in patients with Child-Pugh class A cirrhosis than patients without cirrhosis (P < 0.05). In the comparison between Δ-LS value after AVT and LF score determined by liver biopsy, it was seen that the greatest Δ-LS value was in patients with fibrosis score of 3. An independent relationship was found between Δ-LS after AVT and LF score determined by biopsy (P < 0.05).

CONCLUSIONS

The LS value determined by the elastography point quantification technique is more effective than other noninvasive laboratory methods in demonstrating the CHC treatment response in clinical practice.

Two-dimensional shear wave elastography for assessing liver fibrosis in patients with chronic liver disease: a prospective cohort study

BACKGROUND/AIMS

The objective of this study was to determine whether the newly developed two-dimensional shear wave elastography (2D-SWE, RS85, Samsung-shearwave imaging) was more valid and reliable than transient elastography (TE) for predicting the stage of liver fibrosis.

METHODS

The study prospectively enrolled a total of 116 patients with chronic liver disease who underwent 2D-SWE, TE, laboratory testing, and liver biopsy on the same day from two tertiary care hospitals. One patient with unreliable measurement was excluded. The measurement of 2D-SWE was considered acceptable when a homogenous color pattern in a region of interest of at least 10 mm was detected at 10 different sites. Diagnostic performance was calculated using area under the receiver operating characteristic curve (AUROC).

RESULTS

Liver fibrosis stages included F0 (18%), F1 (19%), F2 (24%), F3 (22%), and F4 (17%). Interclass correlation coefficient for inter-observer agreement in 2D-SWE was 0.994 (95% confidence interval [CI], 0.988 to 0.997). Overall, the results of 2D-SWE and stages of histological fibrosis were significantly correlated (r = 0.601, p < 0.001). For The 2D-SWE showed good diagnostic ability (AUROC, 0.851; 95% CI, 0.773 to 0.911) comparable to TE (AUROC, 0.859; 95% CI, 0.781 to 0.916) for the diagnosis of significant fibrosis (≥ F2), and the cut-off value was 5.8 kPa. AUROC and optimal cut-off of 2D-SWE for the diagnosis of liver cirrhosis were 0.889 (95% CI, 0.817 to 0.940) and 9.6 kPa, respectively. TE showed similar diagnostic performance in distinguishing cirrhosis (AUROC, 0.938; 95% CI, 0.877 to 0.974; p = 0.08).

CONCLUSION

2D-SWE is comparable to TE in diagnosing significant fibrosis and liver cirrhosis with high reliability.

Pancreatic Steatosis Is Associated with Both Metabolic Syndrome and Pancreatic Stiffness Detected by Ultrasound Elastography

INTRODUCTION

There is increasing evidence that pancreatic steatosis (PS) is associated with metabolic syndrome (MS). However, it is not known whether it is associated with PS grade and pancreatic stiffness, or not. We aimed to evaluate the relationship between PS and its grade detected by transabdominal ultrasound, and pancreatic stiffness determined by two-dimensional shearwave elastography (2D-SWE), whether it has clinical significance and its relationship with MS.

METHODS

Patients with and without PS were evaluated prospectively.

RESULTS

Patients with PS had higher odds ratio for MS (OR 5.49). Also, ultrasonographic grade of PS was associated with MS parameters and hepatosteatosis. Pancreatic SWE value was significantly higher in PS group and positively correlated with PS grade, liver fat, MS, number of MS criteria.

DISCUSSION/CONCLUSION

PS and its grade were associated with MS. In this first comprehensive PS-SWE study, we found that pancreas stiffness increased in the presence of PS, in correlation with PS grade and MS.

Nonlinear Characterization of Tissue Viscoelasticity With Acoustoelastic Attenuation of Shear Waves

Shear-wave elastography (SWE) measures shear-wave speed (SWS), which is related to the underlying shear modulus of soft tissue. SWS in soft tissue changes depending on the amount of external strain that soft tissue is subjected to due to the acoustoelastic (AE) phenomenon. In the literature, variations of SWS as a function of applied uniaxial strain were used for nonlinear characterization, assuming soft tissues to be elastic, although soft tissues are indeed viscoelastic in nature. Hence, nonlinear characterization using SWS alone is insufficient. In this work, we use SWS together with shear-wave attenuation (SWA) during incremental quasi-static compressions in order to derive biomechanical characterization based on the AE theory in terms of well-defined storage and loss moduli. As part of this study, we also quantify the effect of applied strain on measurements of SWS and SWA since such confounding effects need to be taken into account when using SWS and/or SWA, e.g., for staging a disease state, while such effects can also serve as an additional imaging biomarker. Our results from tissue-mimicking phantoms with varying oil percentages and ex vivo porcine liver experiments demonstrate the feasibility of our proposed methods. In both experiments, SWA was observed to decrease with applied strain. For 10% compression in ex vivo livers, shear-wave attenuation decreased, on average, by 28% (93 Np/m), while SWS increased, on average, by 20% (0.26 m/s).

Liver Fibrosis Assessment Using Transient Elastography by FibroScan and Shear Wave Elastography by Sonography: A Comparative Cross-sectional Study in an Outpatient Liver Clinic

Background: Non-alcoholic fatty liver disease (NAFLD) is the second most common cause of liver transplantation in the United States, with a continuously growing prevalence. There are several non-invasive methods to detect liver fibrosis, which is defined as the accumulation of extracellular matrix proteins, particularly collagens. It is most commonly associated with chronic liver diseases, such as NAFLD. Objectives: This study aimed to investigate the concordance between transient elastography (TE) and shear wave elastography (SWE) for liver fibrosis staging and also to examine the congruence between the controlled attenuation parameter (CAP) and the B-mode hepatorenal ratio for hepatic steatosis grading in patients with NAFLD. Patients and Methods: In this cross-sectional study conducted during March 2018 - 2019, NAFLD patients, referred to the liver clinic of our center for the non-invasive assessment of hepatic fibrosis, were enrolled. However, patients with sonographic features of cirrhosis, multiple hepatic masses, or moderate to large ascites were excluded; also, patients who were uncooperative during the tests were excluded. Measurements obtained by different tools were recorded. Kolmogorov-Smirnov test, Chi-square test, independent t-test, or Mann-Whitney tests, as well as Pearson’s correlation coefficient test, were used to analyze the data. Results: Sixty-five patients (male-to-female ratio, 1:13), with a median age of 47 years, were included in the study. The tools for assessing fibrosis (r = 0.9538, 95% CI: 0.9252 - 0.9717, P < 0.0001) and steatosis (r = 0.429, 95% CI: 0.2048 - 0.6104, P < 0.0001) were perfectly and moderately correlated, respectively. Sex, age, and body mass index (BMI) did not affect the results. Conclusion: The two elastography modalities showed a strong correlation for fibrosis staging in our study population. Also, the CAP and B-mode hepatorenal ratio were moderately correlated for grading hepatosteatosis. Overall, selection of the best assessment method among the studied modalities depends on factors other than internal validity.

The course and prognostic value of increased pancreas stiffness detected by ultrasound elastography during acute pancreatitis

BACKGROUND

In this study, we determined the pancreatic stiffness (PS) changes in the course of acute pancreatitis (AP) by ultrasound elastography and evaluated its relation with prognosis.

MATERIAL/METHODS

Pancreatic shear wave velocity measurements (SWM) were evaluated at the time of admission to the hospital, following clinical improvement, and one-month after for AP patients and compared to healthy volunteers. Its relationship with clinical severity indexes was evaluated.

RESULTS

The pancreatic SWM value in the healthy group was 7.72 ± 2.50 kPa, and in AP group was 10.97 ± 2.26 kPa (p = 0.000). There was no difference between mild and severe pancreatitis. The mean SWM was 8.96 ± 1.53 kPa after disease remission, and 8.83 ± 1.24 kPa after 1-month.

CONCLUSIONS

PS increases significantly during AP and decreases with clinical improvement, but this was still higher than controls, and it kept its elevation after 1-month. We think that larger, long-term studies are needed to determine the clinicopathological significance of this.

Utility of Hepatic 2D Shear-Wave Elastography in Monitoring Response to Image-Guided Intervention in Children With Chronic Budd-Chiari Syndrome: A Prospective Study

Background: Image-guided interventions for Budd-Chiari syndrome (BCS) reduce hepatic congestion, thereby reducing liver stiffness. Liver stiffness measurements (LSM) by ultrasound may provide a noninvasive marker for assessing treatment response. Objective: To assess the utility of 2D shear-wave elastography (SWE) for monitoring response to image-guided intervention in children with BCS, with attention to changes in LSM in patients with disease recurrence. Materials and Methods: This prospective study included children with chronic BCS and planned image-guided intervention. Color Doppler ultrasound (CDUS) and 2D SWE were performed at baseline; at 24 hours, one month, and three months after intervention; and thereafter every three months or at the time of clinically suspected recurrence. Eighteen children underwent liver biopsy at the time of intervention for fibrosis staging using METAVIR criteria. Disease recurrence was diagnosed by CDUS. Statistical evaluation was performed using non-parametric tests. Results: A total of 32 children (28 boys, 4 girls; mean age: 9.0 years; range: 3-14 years) were included. Median LSM was at baseline 43.7 kPa [interquartile range (IQR): 33.0-65.4), at 24 hours 22.5 kPa (IQR: 16.8-32.0), at one month 18.7 kPa (IQR: 14.2-32.0), and at three months 16.7 kPa (IQR: 11.5-22.5) (p<.05 for all post-intervention time points vs baseline). Nine (28.1%) patients developed recurrence after intervention at mean of 4.4 months. In one patient with recurrence, LSM was higher at 24 hours (52.3 kPa) than at baseline (44.2 kPa). In the remaining eight patients with recurrence, LSM increased at the time of recurrence compared with the prior post-intervention LSM measurement [median absolute increase of 11.0 kPa (IQR: 6.1-24.4 kPa)]. Fibrosis stage was not significantly correlated with baseline LSM (r=0.11, 95% CI: -0.37, 0.54; p=.51) or 24-hour post-intervention LSM (r=0.39, 95% CI: -0.11, 0.73; p=.11). Conclusion: LSM decreased significantly after image-guided intervention for chronic BCS in children, showing a maximal decrease at 24 hours post-intervention. Disease recurrence was typically associated with an increase in LSM compared with the patient's prior measurement. Clinical Impact: LSM obtained by 2D SWE may serve as a useful quantitative adjunct to CDUS in monitoring children with chronic BCS for disease recurrence after percutaneous interventional treatment.

Liver Fibrosis Assessment

Early diagnosis of hepatic fibrosis (HF) is pivotal for management to cease progression to cirrhosis and hepatocellular carcinoma. HF is the telltale sign of chronic liver disease, and confirmed by liver biopsy, which is an invasive technique and inclined to sampling errors. The morphologic parameters of cirrhosis are assessed on conventional imaging such as on ultrasound (US), computed tomography (CT) and magnetic resonance imaging (MRI). Newer imaging modalities such as magnetic resonance elastography and US elastography are reliable and accurate. More research studies on novel imaging modalities such as MRI with diffusion weighted imaging, enhancement by hepatobiliary contrast agents, and CT using perfusion are essential for earlier diagnosis, surveillance and accurate management. The purpose of this article is to discuss non-invasive CT, MRI, and US imaging modalities for diagnosis and stratify HF.

Ultrasound-Based Quantification of Fibrosis and Steatosis with a New Software Considering Transient Elastography as Reference in Patients with Chronic Liver Diseases

The goal of this study was to evaluate the performance of two new ultrasound-based techniques (ShearWave PLUS elastography [2-D-SWE PLUS], SSp PLUS Imaging [SSp PLUS]) implemented on the Aixplorer Mach 30 ultrasound system (Supersonic Imagine, Aix-en-Provence, France) for the non-invasive assessment of liver steatosis and fibrosis, using transient elastography (TE) with the controlled attenuation parameter (CAP) as reference. This monocentric cross-sectional study included 133 consecutive adult patients with chronic hepatopathies. Liver stiffness and steatosis were evaluated in the same session using the techniques mentioned above. An excellent correlation was observed between liver stiffness measurements obtained with 2-D-SWE PLUS and TE (r = 0.92, p < 0.0001). The best cutoff value of 2-D-SWE PLUS for predicting F≥2 was 6.8 kPa; for F≥3, 8.4 kPa; and for F4, 11 kPa. With respect to steatosis evaluation, a strong negative correlation between CAP and SSp PLUS values (r = -0.70, p < 0.0001) was obtained. The best SSp PLUS cutoff value for predicting steatosis was 1537 m/s.

Diagnostic performance of 2D shear wave elastography in predicting liver fibrosis in patients with chronic hepatitis B and C: a histopathological correlation study

PURPOSE

In this study, we investigated the diagnostic efficacy of 2D-Shear Wave Elastography (2D-SWE) in detecting stages of liver fibrosis and determining the disease-specific cut-off values in patients with chronic hepatitis B and C infection, using histopathological analysis as the reference method.

METHOD

Our study included 103 consecutive adult patients with chronic hepatitis B and C infection (CHB and CHC) who had liver biopsy within three months of elastography examination. A real-time 2D-SWE was performed using the LOGIQ E9 system (GE Medical Systems, Wisconsin, USA). The correlation between the liver stiffness measurements and the METAVIR scores was evaluated. The diagnostic performance of 2D-SWE was assessed, and cut-off values were set.

RESULTS

We found a statistically significant positive correlation between elastography values and the degree of liver fibrosis (Spearman's correlation coefficient = 0.76 and 0.83 for CHB and CHC; respectively) (p = 0.0001). The stiffness cut-off values were F ≥ 1: 5.92 kPa, F ≥ 2: 7.69 kPa, F ≥ 3: 8.97 kPa, F ≥ 4: 12.15 kPa in CHB; and F ≥ 1: 6.09 kPa, F ≥ 2: 7.81 kPa, F ≥ 3: 9.0 kPa, F ≥ 4: 12.47 kPa in CHC patients.

CONCLUSION

2D-SWE is reliable and accurate for the diagnosis of liver fibrosis. In selected patients, 2D-SWE may be useful in reducing the need for liver biopsy when staging fibrosis. Further studies in larger prospective series are needed to confirm these results and determine the most appropriate cut-off values for each stage of liver fibrosis.

Hepatic Elastometry and Glissonian Line in the Assessment of Liver Fibrosis

The aim of this study was to identify a method for staging hepatic fibrosis using a non-invasive, rapid and inexpensive technique based on ultrasound morphologic hepatic features. A total of 215 patients with different liver diseases underwent B-mode (2-D brightness mode) ultrasonography, vibration-controlled transient elastography, 2-D shear wave elastography and measurement of the controlled attenuation parameter with transient elastography. B-Mode images of the anterior margin of the left lobe were obtained and processed with automatic Genoa Line Quantification (GLQ) software based on a neural network for staging liver fibrosis. The accuracy of GLQ was 90.6% during model training and 78.9% in 38 different patients with concordant elastometric measures. Receiver operating characteristic curve analysis of GLQ performance using vibration-controlled transient elastography as a reference yielded areas under the curves of 0.851 for F ≥ F1, 0.793 for F ≥ F2, 0.784 for F ≥ F3 and 0.789 for F ≥ F4. GLQ has the potential to be a rapid, easy-to-perform and tolerable method in the staging of liver fibrosis.

Elastografía en tiempo real (Supersonic), experiencia de un centro en Bogotá

Introducción: la elastografía en tiempo real, 2D-SWE (Supersonic), es una prueba no invasiva que se utiliza para determinar la elasticidad del hígado y, de esa forma, calcular el grado de fibrosis hepática. En Colombia, la prueba se introdujo en 2016 y no existen hasta el momento estudios del comportamiento de la prueba en todos los pacientes hepáticos, solo se han publicado en pacientes sanos y cirróticos. Objetivo: analizar la experiencia de la aplicación de la elastografía en tiempo real, en sujetos atendidos en el centro de enfermedades hepáticas y digestivas de Bogotá, Colombia. Materiales y métodos: estudio descriptivo retrospectivo de una cohorte de sujetos atendidos entre marzo de 2016 y julio de 2017. Se realizó una historia clínica completa y una prueba de elastografía en tiempo real (Supersonic). Resultados: se incluyeron 654 sujetos, con una mediana de edad de 55 años (rango intercuartílico [RIC]: 45-64). La mediana de valores de fibrosis expresada en kilopascales (kPs) fue de 8,3, con un promedio de 5 mediciones. Se observó una diferencia significativa en el grado de fibrosis entre los grupos de edad y en relación con el diagnóstico final, donde se evidenció una mayor fibrosis en el grupo de enfermedades colestásicas (autoinmune, colangitis biliar primaria [CBP] y superposición autoinmune-CBP). La tasa global de fracaso fue menor al 1 %. Conclusiones: es la primera descripción del comportamiento de la prueba a nivel nacional. Los valores de rigidez hepática observados en los diferentes estadios demuestran la utilidad de la prueba para la determinación de la fibrosis hepática en pacientes con diferentes patologías.

Estimation of liver elasticity using the finite element method and four-dimensional computed tomography images as a biomarker of liver fibrosis

PURPOSE

Current radiotherapy planning procedures are generally designed based on anatomical information only and use computed tomography (CT) images that do not incorporate organ-functional information. In this study, we developed a method for estimating liver elasticity using the finite element method (FEM) and four-dimensional CT (4DCT) images acquired during radiotherapy planning, and we subsequently evaluated its feasibility as a biomarker for liver fibrosis.

MATERIALS AND METHODS

Twenty patients who underwent 4DCT and ultrasound-based transient elastography (UTE) were enrolled. All patients had chronic liver disease or cirrhosis. Liver elasticity measurements of the UTE were performed on the right lobe of the patient's liver in 20 patients. The serum biomarkers of the aspartate aminotransferase (AST)-to-platelet ratio index (APRI) and fibrosis-4 index (FIB-4) were available in 18 of the 20 total patients, which were measured within 1 week after undergoing 4DCT. The displacement between the 4DCT images obtained at the endpoints of exhalation and inspiration was determined using the actual (via deformable image registration) and simulated (via FEM) respiration-induced displacement. The elasticity of each element of the liver model was optimized by minimizing the error between the actual and simulated respiration-induced displacement. Then, each patient's estimated liver elasticity was defined as the mean Young's modulus of the liver's right lobe and that of the whole liver using the estimated elasticity map. The estimated liver elasticity was evaluated for correlations with the elasticity obtained via UTE and with two serum biomarkers (APRI and FIB-4).

RESULTS

The mean ± standard deviation (SD) of the errors between the actual and simulated respiration-induced displacement in the liver model was 0.54 ± 0.33 mm. The estimated liver's right lobe elasticity was statistically significantly correlated with the UTE (r = 0.87, P < 0.001). Furthermore, the estimated whole liver elasticity was statistically significantly correlated with the UTE (r = 0.84, P < 0.001), APRI score (r = 0.62, P = 0.005), and FIB-4 score (r = 0.54, P = 0.021).

CONCLUSION

In this study, liver elasticity was estimated through FEM-based simulation and actual respiratory-induced liver displacement obtained from 4DCT images. Furthermore, we assessed that the estimated elasticity of the liver's right lobe was strongly correlated with the UTE. Therefore, the estimated elasticity has the potential to be a feasible imaging biomarker for assessing liver fibrosis using only 4DCT images without additional inspection or equipment costs. Because our results were derived from a limited sample of 20 patients, it is necessary to evaluate the accuracy of elasticity estimation for each liver segment on larger groups of biopsied patients to utilize liver elasticity information for radiotherapy planning.

Role of Noninvasive Tests in Clinical Gastroenterology Practices to Identify Patients With Nonalcoholic Steatohepatitis at High Risk of Adverse Outcomes: Expert Panel Recommendations

Nonalcoholic fatty liver disease (NAFLD) is generally considered a silent and potentially reversible condition. The subtype of NAFLD that can be classified as nonalcoholic steatohepatitis (NASH) can progress to advanced fibrosis and cirrhosis. Because of the metabolic nature of the pathogenic mechanism underlying NAFLD and NASH, it is often accompanied by common comorbidities such as obesity, insulin resistance, and type 2 diabetes mellitus. The increase in the prevalence of these comorbidities has resulted in a parallel increase in the prevalence of NAFLD and NASH, globally, nationally, and even in children. In recent years, it has been identified that the stage of fibrosis is the most important predictor of liver outcomes; therefore, identifying patients with NAFLD and NASH with more advanced stages of fibrosis can be essential for optimal management. Several noninvasive tools for diagnosing and staging NAFLD and NASH are available, but simple and straightforward recommendations on the use of these tools are not. Recognizing these unmet needs, hepatologists who are members of the American College of Gastroenterology and the Chronic Liver Disease Foundation created a practical decision tree/algorithm to risk stratify NAFLD/NASH as a resource in gastroenterology/hepatology clinical practices. This review will provide insight into how this algorithm was developed, describe it in detail, and provide recommendations for its use in clinical practice.

Agreement Between 2-Dimensional Shear Wave and Transient Elastography Values for Diagnosis of Advanced Chronic Liver Disease

BACKGROUND & AIMS

Inter-platform variation in liver stiffness evaluation (LSE) could hinder dissemination and clinical implementation of new ultrasound methods. We aimed to determine whether measurements of liver stiffness by bi-dimensional shear wave elastography (2D-SWE) with a Supersonic Imagine apparatus are comparable to those made by vibration-controlled transient elastography (VCTE).

METHODS

We collected data from 1219 consecutive patients with chronic liver disease who underwent LSE by VCTE and 2D-SWE (performed by blinded operators), on the same day, at a single center in France from September 2011 through June 2019. We assessed the ability of liver stiffness value distributions and 2D-SWE performances to identify patients with compensated advanced chronic liver disease (cACLD) according to the Baveno VI criteria, based on VCTE cut-off values.

RESULTS

VCTE and 2D-SWE values correlated (Pearson's correlation coefficient, 0.882; P < .0001; Lin concordance coefficient, 0.846; P < .0001). The median stiffness values were 6.7 kPa with VCTE (interquartile range, 4.8-11.6 kPa) and 7.1 kPa with 2D-SWE (interquartile range, 5.4-11.1 kPa) (P = .736). 2D-SWE values were slightly higher in the low percentiles and lower in the high percentiles; the best match with VCTE values were at approximately 7-9 kPa. The area under the curve of 2D-SWE for identifying of VCTE values below 10 was 0.964 (95% CI, 0.952-0.976) and for VCTE values above 15 kPa was 0.976 (95% CI, 0.963-0.988), with Youden index-associated cut-off values of 9.5 and 13kPa and best accuracy cut-off values of 10 kPa and 14 kPa, respectively. A 2D-SWE cut-off value of 10 kPa detected VCTE values below 10k Pa with 92% sensitivity, 87% specificity, and 91% accuracy.

CONCLUSIONS

Measurement of liver stiffness by VCTE or 2D-SWE produces comparable results. 2D-SWE accurately identifies patients with cACLD according to the Baveno VI criteria based on VCTE cut-off values. A 10 kPa 2D-SWE cut-off value can be used to rule out cACLD.

Deep learning networks on chronic liver disease assessment with fine-tuning of shear wave elastography image sequences

Chronic liver disease (CLD) is currently one of the major causes of death worldwide. If not treated, it may lead to cirrhosis, hepatic carcinoma and death. Ultrasound (US) shear wave elastography (SWE) is a relatively new, popular, non-invasive technique among radiologists. Although many studies have been published validating the SWE technique either in a clinical setting, or by applying machine learning on SWE elastograms, minimal work has been done on comparing the performance of popular pre-trained deep learning networks on CLD assessment. Currently available literature reports suggest technical advancements on specific deep learning structures, with specific inputs and usually on a limited CLD fibrosis stage class group, with limited comparison on competitive deep learning schemes fed with different input types. The aim of the present study is to compare some popular deep learning pre-trained networks using temporally stable and full elastograms, with or without augmentation as well as propose suitable deep learning schemes for CLD diagnosis and progress assessment. 200 liver biopsy validated patients with CLD, underwent US SWE examination. Four images from the same liver area were saved to extract elastograms and processed to exclude areas that were temporally unstable. Then, full and temporally stable masked elastograms for each patient were separately fed into GoogLeNet, AlexNet, VGG16, ResNet50 and DenseNet201 with and without augmentation. The networks were tested for differentiation of CLD stages in seven classification schemes over 30 repetitions using liver biopsy as the reference. All networks achieved maximum mean accuracies ranging from 87.2%-97.4% and area under the receiver operating characteristic curves (AUCs) ranging from 0.979-0.990 while the radiologists had AUCs ranging from 0.800-0.870. ResNet50 and DenseNet201 had better average performance than the other networks. The use of the temporal stability mask led to improved performance on about 50% of inputs and network combinations while augmentation led to lower performance for all networks. These findings can provide potential networks with higher accuracy and better setting in the CLD diagnosis and progress assessment. A larger data set would help identify the best network and settings for CLD assessment in clinical practice.

Noninvasive imaging assessment of portal hypertension

Portal hypertension (PH) is a spectrum of complications of chronic liver disease (CLD) and cirrhosis, with manifestations including ascites, gastroesophageal varices, splenomegaly, hypersplenism, hepatic hydrothorax, hepatorenal syndrome, hepatopulmonary syndrome and portopulmonary hypertension. PH can vary in severity and is diagnosed via invasive hepatic venous pressure gradient measurement (HVPG), which is considered the reference standard. Accurate diagnosis of PH and assessment of severity are highly relevant as patients with clinically significant portal hypertension (CSPH) are at higher risk for developing acute variceal bleeding and mortality. In this review, we discuss current and upcoming noninvasive imaging methods for diagnosis and assessment of severity of PH.

Early development of hepatic fibrosis after Fontan procedure: A non-invasive study of a subclinical liver disease

BACKGROUND

To evaluate subclinical liver fibrosis after Fontan procedure using a comprehensive method that reflects the overall liver status rather than the focal biopsy lesion.

METHOD

This cross-sectional study included 66 patients without symptoms of liver disease who had at least 5 years of elapsed time since the Fontan procedure (time since Fontan procedure 17.5 ± 7.3 years). Serum enhanced liver fibrosis (ELF) scores and 2D shear wave elastography (SWE), which are expected to detect liver fibrosis earlier than liver enzyme tests and ultrasonography, were evaluated along with general examinations.

RESULTS

Liver cirrhosis diagnosed by ultrasonography showed a marked increase 16 years after surgery (elapsed time: 6-15 years since Fontan, 43.8%; 16-25 years, 70.8%; 26-35 years, 90.0%). The age-adjusted ELF score and liver stiffness according to SWE were elevated during the early postoperative period (6-15 years since Fontan). In adulthood (elapsed time > 16 years), the adjusted ELF score was correlated with liver stiffness (r = 0.514, p = .009) and liver enzyme levels. There was no correlation between liver fibrosis and the Fontan palliation type. AST to platelet count ratio and FIB-4, which are non-invasive fibrosis markers, presumed absence of fibrosis in approximately 90% of patients.

CONCLUSIONS

In the evaluation of early liver fibrosis after the Fontan procedure, abnormal findings of 2D SWE and ELF scores were observed before abnormal ultrasound and liver enzyme results. Therefore, these indicators may be helpful for the diagnosis of early liver fibrosis, and further longitudinal study might be needed.

Technical Performance of Two-Dimensional Shear Wave Elastography for Measuring Liver Stiffness: A Systematic Review and Meta-Analysis

Objective

To assess the technical performance of two-dimensional shear wave elastography (2D-SWE) for measuring liver stiffness.

Materials and Methods

The Ovid-MEDLINE and EMBASE databases were searched for studies reporting the technical performance of 2D-SWE, including concerns with technical failures, unreliable measurements, interobserver reliability, and/or intraobserver reliability, published until June 30, 2018. The pooled proportion of technical failure and unreliable measurements was calculated using meta-analytic pooling via the random-effects model and inverse variance method for calculating weights. Subgroup analyses were performed to explore potential causes of heterogeneity. The pooled intraclass correlation coefficients (ICCs) for interobserver and intraobserver reliability were calculated using the Hedges-Olkin method with Fisher's Z transformation of the correlation coefficient.

Results

The search yielded 34 articles. From 20 2D-SWE studies including 6196 patients, the pooled proportion of technical failure was 2.3% (95% confidence interval [CI], 1.3–3.9%). The pooled proportion of unreliable measurements from 20 studies including 6961 patients was 7.5% (95% CI, 4.7–11.7%). In the subgroup analyses, studies conducting more than three measurements showed fewer unreliable measurements than did those with three measurements or less, but no intergroup difference was found in technical failure. The pooled ICCs for interobserver reliability (from 10 studies including 517 patients) and intraobserver reliability (from 7 studies including 679 patients) were 0.87 (95% CI, 0.82–0.90) and 0.93 (95% CI, 0.89–0.95), respectively, suggesting good to excellent reliability.

Conclusion

2D-SWE shows good technical performance for assessing liver stiffness, with high technical success and reliability. Future studies should establish the quality criteria and optimal number of measurements.

Ultrasound-guided transient elastography and two-dimensional shear wave elastography for assessment of liver fibrosis: emphasis on technical success and reliable measurements

Purpose

This study investigated whether the use of ultrasound (US) guidance in transient elastography (TE) improved the technical success and reliability of liver stiffness (LS) measurements and whether 2-dimensional (2D) shear wave elastography (SWE) provided reliable LS measurements if TE measurements failed.

Methods

In this prospective study, 292 participants (male:female, 189:103; median age, 60 years) with chronic liver disease (CLD) were enrolled. LS was measured via the consecutive use of conventional TE, 2D-SWE, and US-guided TE. The technical success rates and reliable LS measurement rates of the three elastography techniques were compared. The risk factors for TE failure were assessed through univariate and multivariate logistic regression models.

Results

US-guided TE was associated with a higher technical success rate (281 of 292, 96.2%) and a higher reliable measurement rate (266 of 292, 91.1%) than conventional TE (technical success: 256 of 292, 87.7%; reliable measurements: 231 of 292, 79.1%; P<0.001 for both). In participants for whom conventional TE failed, 2D-SWE provided high rates of technical success (36 of 36, 100%) and reliable measurements (30 of 36, 83.3%). TE failure was associated with female sex (odds ratio [OR], 5.85; 95% confidence interval [CI], 1.30 to 26.40), severe reverberation artifacts (OR, 8.79; 95% CI, 3.93 to 19.69), and high skin-to-liver capsule depth (OR, 1.23; 95% CI, 1.09 to 1.39).

Conclusion

US guidance in TE improved the technical success and reliable measurement rates in the assessment of LS in patients with CLD. In participants for whom TE failed, subsequent 2D-SWE successfully delivered reliable LS measurements.

Why Are Viscosity and Nonlinearity Bound to Make an Impact in Clinical Elastographic Diagnosis?

The adoption of multiscale approaches by the biomechanical community has caused a major improvement in quality in the mechanical characterization of soft tissues. The recent developments in elastography techniques are enabling in vivo and non-invasive quantification of tissues' mechanical properties. Elastic changes in a tissue are associated with a broad spectrum of pathologies, which stems from the tissue microstructure, histology and biochemistry. This knowledge is combined with research evidence to provide a powerful diagnostic range of highly prevalent pathologies, from birth and labor disorders (prematurity, induction failures, etc.), to solid tumors (e.g., prostate, cervix, breast, melanoma) and liver fibrosis, just to name a few. This review aims to elucidate the potential of viscous and nonlinear elastic parameters as conceivable diagnostic mechanical biomarkers. First, by providing an insight into the classic role of soft tissue microstructure in linear elasticity; secondly, by understanding how viscosity and nonlinearity could enhance the current diagnosis in elastography; and finally, by compounding preliminary investigations of those elastography parameters within different technologies. In conclusion, evidence of the diagnostic capability of elastic parameters beyond linear stiffness is gaining momentum as a result of the technological and imaging developments in the field of biomechanics.

Shear Wave Elastography to Assess Perineal Body Stiffness During Labor

OBJECTIVES

The objective of this study was to evaluate perineal body stiffness intrapartum using shear wave elastography ultrasound and to study its association with maternal and labor characteristics.

METHODS

This was a prospective observational study. Pregnant women with term pregnancy who had been admitted for labor management were recruited into the study. Transperineal shear wave elastography of perineal body was performed. Maternal and labor data were retrieved from electronic medical charts.

RESULTS

Thirty-two patients' data were available for analysis. Mean (SD) melastography modulus was 15.33 (5.49). While comparing the mean elastography modulus across maternal and labor characteristics, the difference was statistically different between parity, cervical dilation, and perineal laceration presence groups (P < 0.05). The mean of elastography modulus of primiparous women with cervical dilation less than 3 cm was 21.47 kPa, whereas that of multiparous women was 13.17 kPa (P = 0.0511). Perineal laceration was more prevalent in women with stiffer perineal body. The risk of having perineal laceration compared with no perineal laceration was 29.1% higher for each additional unit increase in perineal body elastography modulus (odds ratio, 0.709; 95% confidence interval, 0.507-0.992).

CONCLUSIONS

Shear wave elastography can be used to quantify perineal body stiffness. Primiparous women in early stages of labor have stiffer perineal body than multiparous women in any stage of labor and primiparous women in late stage of labor.

Comparison of Sound Touch Elastography, Shear Wave Elastography and Vibration-Controlled Transient Elastography in Chronic Liver Disease Assessment using Liver Biopsy as the "Reference Standard"

Chronic liver disease (CLD) is currently a major cause of death. Ultrasound elastography (USE) is an imaging method that has been developed for CLD assessment. Our aim in the study described here was to evaluate and compare a new commercial variant of USE, sound touch elastography (STE), with already established USE methods, shear wave elastography (SWE) and vibration-controlled transient elastography (VCTE), using liver biopsy as the "reference standard." For our study, 139 consecutive patients underwent standard liver STE, SWE and VCTE examinations with the corresponding ultrasound devices. A receiver operator characteristic (ROC) curve analysis was performed on the stiffness values measured with each method. ROC analysis revealed, for SWE, STE and VCTE, areas under the ROC curve of 0.9397, 0.9224 and 0.9348 for fibrosis stage (F), F ≥ F1; 0.9481, 0.9346 and 0.9415 for F ≥ F2; 0.9623, 0.9591 and 0.9631 for F ≥ F3; and 0.9581, 0.9541 and 0.9632 for F = F4, respectively. In conclusion, STE performs similarly to SWE and VCTE in CLD stage differentiation.

Accuracy of real-time shear wave elastography in staging hepatic fibrosis: a meta-analysis

Background

Chronic liver disease (CLD) is an important cause of morbidity and mortality and can lead to hepatic fibrosis. This study was conducted to evaluate the diagnostic value of real-time shear wave elastography (SWE) in the assessment of hepatic fibrosis.

Methods

A systematic search of databases was performed for publications on SWE during the period between 2010 and 2017. The identified studies were analyzed using Meta-disc 1.4 software to integrate and analyze the data.

Results

Eleven studies comprising 1560 patients were included for analysis. The pooled sensitivity, specificity and diagnostic odds ratio were 0.85 (95% CI: 0.82–0.87), 0.79 (95% CI: 0.76–0.82) and 30.81 (95% CI: 16.55–57.34), respectively for patients with a Metavir-score of ≥ F2; 0.87 (95% CI: 0.84–0.91), 0.84 (95% CI: 0.82–0.87), 41.45 (95% CI:18.25–94.45), respectively for patients with ≥ F3; 0.88(95% CI: 0.83–0.91), 0.91 (95% CI: 0.89–0.92), 67.18 (95% CI:30.02–150.31), respectively for patients with ≥ F4. The areas under the receiver operating characteristic curve of the three groups were 0.9147, 0.9223 and 0.9520, respectively.

Conclusions

Our work demonstrates that SWE is highly accurate for detecting and staging hepatic fibrosis.

Non-invasive assessment of hepatic fibrosis: comparison of MR elastography to transient elastography and intravoxel incoherent motion diffusion-weighted MRI

OBJECTIVE

To compare the ability of MR elastography (MRE) with transient elastography (TE) and intravoxel incoherent motion (IVIM) diffusion-weighted MRI in staging hepatic fibrosis (HF).

MATERIALS AND METHODS

100 patients with chronic liver disease and 25 healthy volunteers underwent preoperative MRE, IVIM on a 3T MRI unit, and ultrasound-based TE. Liver stiffness measurement from MRE (LSM-MRE) and liver stiffness measurement from TE (LSM-TE) were measured; four diffusion parameters including the true diffusion coefficient (D_t), pseudo-diffusion coefficient, perfusion fraction (f), and apparent diffusion coefficient (ADC) were calculated. Receiver operating characteristic (ROC) curves were performed for significant parameters to compare the diagnosis performance for detecting HF.

RESULTS

LSM-MRE and LSM-TE values showed positive correlation with the fibrosis stage (r = 0.910 and 0.813, P < 0.001). D_t, f, and ADC values showed negative correlation with the fibrosis stage (r = - 0.727, - 0.503, and - 0.601, all P < 0.001). The area under the ROC curve (AUC) of LSM-MRE (AUC = 0.965, 0.957, 0.983) was significantly higher than that of LSM-TE (AUC = 0.906, 0.913, 0.931) and D_t (AUC = 0.875, 0.879, 0.861) in discriminating significant HF (≥ F2), advanced HF (≥ F3), or cirrhosis (F4) (all P < 0.05). Although LSM-TE showed higher AUCs than D_t in detecting fibrosis stages, there were no significant differences between LSM-TE and D_t (P > 0.05) except for detecting F4 (P < 0.05).

CONCLUSION

MRE shows excellent diagnostic performance for predicting significant fibrosis, advanced fibrosis compared with TE and IVIM, while TE and IVIM have comparable diagnostic performance.

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.

Temporal stability assessment in shear wave elasticity images validated by deep learning neural network for chronic liver disease fibrosis stage assessment

PURPOSE

To automatically detect and isolate areas of low and high stiffness temporal stability in shear wave elastography (SWE) image sequences and define their impact in chronic liver disease (CLD) diagnosis improvement by means of clinical examination study and deep learning algorithm employing convolutional neural networks (CNNs).

MATERIALS AND METHODS

Two hundred SWE image sequences from 88 healthy individuals (F0 fibrosis stage) and 112 CLD patients (46 with mild fibrosis (F1), 16 with significant fibrosis (F2), 22 with severe fibrosis (F3), and 28 with cirrhosis (F4)) were analyzed to detect temporal stiffness stability between frames. An inverse Red, Green, Blue (RGB) colormap-to-stiffness process was performed for each image sequence, followed by a wavelet transform and fuzzy c-means clustering algorithm. This resulted in a binary mask depicting areas of high and low stiffness temporal stability. The mask was then applied to the first image of the SWE sequence, and the derived, masked SWE image was used to estimate its impact in standard clinical examination and CNN classification. Regarding the impact of the masked SWE image in clinical examination, one measurement by two radiologists was performed in each SWE image and two in the corresponding masked image measuring areas with high and low stiffness temporal stability. Then, stiffness stability parameters, interobserver variability evaluation and diagnostic performance by means of ROC analysis were assessed. The masked and unmasked sets of SWE images were fed into a CNN scheme for comparison.

RESULTS

The clinical impact evaluation study showed that the masked SWE images decreased the interobserver variability of the radiologists' measurements in the high stiffness temporal stability areas (interclass correlation coefficient (ICC) = 0.92) compared to the corresponding unmasked ones (ICC = 0.76). In terms of diagnostic accuracy, measurements in the high-stability areas of the masked SWE images (area-under-the-curve (AUC) ranging from 0.800 to 0.851) performed similarly to those in the unmasked SWE images (AUC ranging from 0.805 to 0.893). Regarding the measurements in the low stiffness temporal stability areas of the masked SWE images, results for interobserver variability (ICC = 0.63) and diagnostic accuracy (AUC ranging from 0.622 to 0.791) were poor. Regarding the CNN classification, the masked SWE images showed improved accuracy (ranging from 82.5% to 95.5%) compared to the unmasked ones (ranging from 79.5% to 93.2%) for various CLD stage combinations.

CONCLUSION

Our detection algorithm excludes unreliable areas in SWE images, reduces interobserver variability, and augments CNN's accuracy scores for many combinations of fibrosis stages.

Diagnostic Accuracy of 2-Dimensional Shear Wave Elastography for the Staging of Liver Fibrosis: A Meta-analysis

OBJECTIVES

To evaluate the overall accuracy of 2-dimensional shear wave elastography (SWE) for the staging of liver fibrosis.

METHODS

Literature databases and conference abstracts were searched from 2000 to September 2017. Sensitivity, specificity, and other information were extracted from the included studies. Methodological quality was assessed with Quality Assessment of Diagnostic Accuracy Studies 2 tools. Data were synthesized by a bivariate hierarchical model.

RESULTS

The summary sensitivity and specificity were 0.85 (95% confidence interval [CI], 0.80-0.89) and 0.79 (95% CI, 0.72-0.85) for fibrosis stage F≥2, 0.90 (95% CI, 0.87-0.93) and 0.85 (95% CI, 0.80-0.89) for F≥3, and 0.89 (95% CI, 0.84-0.93) and 0.92 (95% CI, 0.89-0.95) for F=4, respectively. The areas under the summary receiver operating characteristic curve for F≥2, F≥3, and F=4 was 0.81, 0.77, and 0.84.

CONCLUSIONS

Two-dimensional SWE is a good noninvasive method for the diagnosis of substantial liver fibrosis and cirrhosis. Further studies are needed to assess severe fibrosis and to perform head-to-head comparisons of 2-dimensional SWE and other imaging modalities for the evaluation of liver fibrosis.

NAFLD evaluation: Which is more appropriate, multislice computed tomography or ultrasound real-time shear wave elastography?

OBJECTIVE

This study aims to assess the value of ultrasound real-time shear wave elastography (US-SWE) for evaluation of nonalcoholic fatty liver disease (NAFLD) in a rabbit model compared with multislice computed tomography (MSCT).

MATERIAL AND METHODS

Twenty-six rabbits were fed with high-fat, high-cholesterol diet and six rabbits were fed with a standard diet. All rabbits were performed with MSCT and US-SWE at various time points to measure changes in liver parenchyma. The diagnostic efficiency of US-SWE was analyzed using receiver operating characteristics (ROC) curves compared with MSCT based on the liver pathology.

RESULTS

The statistically significant differences in the areas under the ROC curves between using MSCT and US-SWE modalities were detected to discriminate between normal vs. NAFLD or higher severity pathology. Similarly, for normal or NAFLD vs. borderline or NASH livers, statistically significant differences between using US-SWE and MSCT modalities were also detected for nonalcoholic steatohepatitis (NASH) vs. lower severity pathology.

CONCLUSIONS

MSCT, but not US-SWE, had a better ability to differentiate normal or NAFLD livers from higher severity NAFLD livers. However, the diagnostic efficiency of US-SWE was superior to that of MSCT for differentiating NASH from normal or lower severity NAFLD.

Noninvasive assessment and risk factors of liver fibrosis in patients with thalassemia major using shear wave elastography

OBJECTIVES

This study aimed to estimate the prevalence of liver fibrosis and assess the risk factors for developing significant liver fibrosis in patients with Thalassemia Major (TM).

METHODS

All patients with TM over the age of 10 years were included in the study.

RESULTS

A total of 94 eligible patients underwent 2-D SWE. The median age was 26.7 years. The median of the average 5-year serum ferritin (5yrSF) and liver iron concentration (LIC) assessed by MRI T2* were 1326 µg/L and 6.7 mg/g dw, respectively. Hepatitis C and hepatitis B core antibodies were positive in 38% and 1% of the patients respectively. The proportion of patients with significant fibrosis was 60%. Male gender increased the risk of significant fibrosis (Odds ratio of 0.4; p = .0373). Additionally, the 5yrSF (p = .00661), the LIC (p = .0225) and the lowest LIC of the previous 5 years (p = .0211) were significant. In the multivariable logistic regression model, only 5yrSF (p = .0035) and gender (p = .00984) remained significant.

CONCLUSIONS

The risk of liver fibrosis is associated with iron overload and gender in patients with TM.

Accuracy of 2D shear wave elastography in the diagnosis of liver fibrosis in patients with chronic hepatitis C

PURPOSE

This prospective study was conducted to assess the diagnostic accuracy of two-dimensional shear wave elastography (2D SWE) in the diagnosis of liver fibrosis in patients with chronic liver disease and hepatitis C virus (HCV) compared with the serum liver fibrosis biomarkers using the results of liver biopsy as the reference standard.

METHODS

We analyzed 233 consecutive HCV patients. On the same day, 2D SWE m, biochemical tests, and liver biopsy were performed. We used the METAVIR staging system and receiver operating characteristic curves for the analysis.

RESULTS

The success rate of 2D-SWE was 98.7%. The median shear wave velocities (SWVs) of patients in the F0, F1, F2, F3, and F4 stages were 1.35 m/s, 1.42 m/s, 1.58 m/s, 1.83 m/s, and 2.13 m/s, respectively, demonstrating a stepwise increase (P < .0001). The accuracy of 2D-SWE in the prediction of ≥F1, ≥F2, ≥F3, and F4 was .888 (95% CI: .85-.93), .915 (95% CI: .88-095), .940 (95% CI: .91-.97), and .949 (95% CI: .92-.97), respectively. 2D-SWE was significantly superior to serum liver fibrosis biomarkers.

CONCLUSION

2D-SWE was positively correlated with the severity of liver fibrosis and was more useful for to predict all liver fibrosis grades in HCV patients than liver fibrosis biomarkers.

Assessing Liver Stiffness by 2-D Shear Wave Elastography in a Healthy Cohort

The aim of this study was to assess the normal ranges of liver stiffness measurements (LSMs) in participants with healthy livers, using General Electric 2-D shear wave elastography (2-D-SWE-GE) compared with transient elastography (TE). We included 80 participants with healthy livers and without known liver disease, in whom liver stiffness was evaluated in the same session using two elastographic methods, TE and 2-D-SWE-GE. Reliable LSMs were defined for TE as the median of 10 measurements with a success rate of ≥60% and an interquartile range (IQR) < 30%, and for 2-D-SWE-GE, as the median of 10 measurements acquired in a homogenous area and an IQR < 30%. Participants with LSMs > 6.5 kPa by TE were excluded. Reliable LSMs were obtained in 79 participants (98.7%) by means of 2-D-SWE-GE and in 80 participants (100%) by means of TE (p = 0.9). The mean LSM obtained by 2-D-SWE-GE in our cohort of participants with healthy livers was 5.1 ± 1.3 kPa, which was significantly higher than the LSM assessed by TE (4.3 ± 0.9 kPa, p < 0.0001). In 2-D SWE-GE, mean LSMs were significantly higher for men than for women, 5.9 ± 1.2 kPa versus 4.7 ± 1.2 kPa (p = 0.0005). In conclusion, 2-D-SWE-GE has very good feasibility (98.7%) in healthy persons. The mean LSM determined by 2-D-SWE-GE in healthy participants was 5.1 ± 1.3 kPa. LSMs obtained by means of 2-D-SWE-GE were higher than those obtained by TE in participants with healthy livers.

An analysis of intrinsic variations of low-frequency shear wave speed in a stochastic tissue model: the first application for staging liver fibrosis

Shear wave elastography is increasingly being used to non-invasively stage liver fibrosis by measuring shear wave speed (SWS). This study quantitatively investigates intrinsic variations among SWS measurements obtained from heterogeneous media such as fibrotic livers. More specifically, it aims to demonstrate that intrinsic variations in SWS measurements, in general, follow a non-Gaussian distribution and are related to the heterogeneous nature of the medium being measured. Using the principle of maximum entropy (ME), our primary objective is to derive a probability density function (PDF) of the SWS distribution in conjunction with a lossless stochastic tissue model. Our secondary objective is to evaluate the performance of the proposed PDF using Monte Carlo (MC)-simulated shear wave (SW) data against three other commonly used PDFs. Based on statistical evaluation criteria, initial results showed that the derived PDF fits better to MC-simulated SWS data than the other three PDFs. It was also found that SW fronts stabilized after a short (compared with the SW wavelength) travel distance in lossless media. Furthermore, in lossless media, the distance required to stabilize the SW propagation was not correlated to the SW wavelength at the low frequencies investigated (i.e. 50, 100 and 150 Hz). Examination of the MC simulation data suggests that elastic (shear) wave scattering became more pronounced when the volume fraction of hard inclusions increased from 10 to 30%. In conclusion, using the principle of ME, we theoretically demonstrated for the first time that SWS measurements in this model follow a non-Gaussian distribution. Preliminary data indicated that the proposed PDF can quantitatively represent intrinsic variations in SWS measurements simulated using a two-phase random medium model. The advantages of the proposed PDF are its physically meaningful parameters and solid theoretical basis.

A Machine-Learning Algorithm Toward Color Analysis for Chronic Liver Disease Classification, Employing Ultrasound Shear Wave Elastography

The purpose of the present study was to employ a computer-aided diagnosis system that classifies chronic liver disease (CLD) using ultrasound shear wave elastography (SWE) imaging, with a stiffness value-clustering and machine-learning algorithm. A clinical data set of 126 patients (56 healthy controls, 70 with CLD) was analyzed. First, an RGB-to-stiffness inverse mapping technique was employed. A five-cluster segmentation was then performed associating corresponding different-color regions with certain stiffness value ranges acquired from the SWE manufacturer-provided color bar. Subsequently, 35 features (7 for each cluster), indicative of physical characteristics existing within the SWE image, were extracted. A stepwise regression analysis toward feature reduction was used to derive a reduced feature subset that was fed into the support vector machine classification algorithm to classify CLD from healthy cases. The highest accuracy in classification of healthy to CLD subject discrimination from the support vector machine model was 87.3% with sensitivity and specificity values of 93.5% and 81.2%, respectively. Receiver operating characteristic curve analysis gave an area under the curve value of 0.87 (confidence interval: 0.77-0.92). A machine-learning algorithm that quantifies color information in terms of stiffness values from SWE images and discriminates CLD from healthy cases is introduced. New objective parameters and criteria for CLD diagnosis employing SWE images provided by the present study can be considered an important step toward color-based interpretation, and could assist radiologists' diagnostic performance on a daily basis after being installed in a PC and employed retrospectively, immediately after the examination.

Evaluation of hepatic fibrosis: a review from the society of abdominal radiology disease focus panel

Hepatic fibrosis is potentially reversible; however early diagnosis is necessary for treatment in order to halt progression to cirrhosis and development of complications including portal hypertension and hepatocellular carcinoma. Morphologic signs of cirrhosis on ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI) alone are unreliable and are seen with more advanced disease. Newer imaging techniques to diagnose liver fibrosis are reliable and accurate, and include magnetic resonance elastography and US elastography (one-dimensional transient elastography and point shear wave elastography or acoustic radiation force impulse imaging). Research is ongoing with multiple other techniques for the noninvasive diagnosis of hepatic fibrosis, including MRI with diffusion-weighted imaging, hepatobiliary contrast enhancement, and perfusion; CT using perfusion, fractional extracellular space techniques, and dual-energy, contrast-enhanced US, texture analysis in multiple modalities, quantitative mapping, and direct molecular imaging probes. Efforts to advance the noninvasive imaging assessment of hepatic fibrosis will facilitate earlier diagnosis and improve patient monitoring with the goal of preventing the progression to cirrhosis and its complications.

Shear Wave Liver Elastography with a Propagation Map: Diagnostic Performance and Inter-Observer Correlation for Hepatic Fibrosis in Chronic Hepatitis

The aim of this study was to determine the performance of shear wave elastography (SWE) with a propagation map in the diagnosis of hepatic fibrosis, and to assess its reliability with transient elastography (TE) as the reference standard. Our prospective study included 115 consecutive patients with suspected or alleged chronic hepatitis. Patients underwent SWE by two different operators and TE by sonographers on the same day. The correlation coefficient of the intra-class correlation test between an experienced radiologist and a third-year radiology resident was 0.878. There was a moderate correlation between SWE and TE (r = 0.511) in the diagnosis of hepatic fibrosis. The best cutoff values predicting significant hepatic fibrosis and liver cirrhosis by SWE were >1.78 m/s (area under the receiver operating characteristic curve [AUROC] = 0.777) and >2.24 m/s (AUROC = 0.935), respectively. SWE with a propagation map is a reliable method for predicting hepatic fibrosis regardless of operator experience.

Validation of Shear Wave Elastography Cutoff Values on the Supersonic Aixplorer for Practical Clinical Use in Liver Fibrosis Staging

The purpose of this study was to determine the validity of previously established ultrasound shear wave elastography (SWE) cut-off values (≥F2 fibrosis) on an independent cohort of patients with chronic liver disease. In this cross-sectional study, approved by the institutional review board and compliant with the Health Insurance Portability and Accountability Act, 338 patients undergoing liver biopsy underwent SWE using an Aixplorer ultrasound machine (SuperSonic Imagine, Aix-en-Provence, France). Median SWE values were calculated from sets of 10 elastograms. A single blinded pathologist evaluated METAVIR fibrosis staging as the gold standard. The study analyzed 277 patients with a mean age of 48 y. On pathologic examination, 212 patients (76.5%) had F0-F1 fibrosis, whereas 65 (23.5%) had ≥F2 fibrosis. Spearman's correlation of fibrosis with SWE was 0.456 (p < 0.001). A cut-off value of 7.29 kPa yielded sensitivity of 95.4% and specificity of 50.5% for the diagnosis of METAVIR stage ≥F2 liver fibrosis in patients with liver disease using the SuperSonic Imagine Aixplorer SWE system.

2D Shear Wave Elastography of Liver in Patients with Primary Extrahepatic Portal Vein Obstruction

AIMS

To evaluate liver stiffness (LS) in patients of primary extrahepatic portal vein obstruction (EHPVO) using 2D shear wave elastography (SWE) and compare it with healthy volunteers.

METHODS

Fifty patients (mean age: 22.4 years) of EHPVO and 25 healthy volunteers were included in the study. Liver function tests and viral markers were done in both groups and endoscopy in EHPVO group, followed by ultrasonography and SWE of liver. Liver elastography was done with patients/volunteers in supine position through right intercostal space. The LS for right lobe of liver was recorded in kilopascals. Three such measurements were taken and the mean of both groups were compared. The variables were also correlated with mean LS using Pearson's correlation coefficient in EHPVO group.

RESULTS

There was no significant difference in the mean LS in patients of EHPVO (5.96 kPa) and healthy volunteers (5.47 kPa) (P = 0.093). There was no significant correlation between LS with duration of symptoms, hematemesis, esophageal varices, total bilirubin, serum alkaline phosphatase and aspartate aminotranferase levels in EHPVO group.

CONCLUSION

SWE of liver may be used as a simple additional tool in the diagnosis of patients of EHPVO who show LS values similar to normal liver.

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.

Two-dimensional Shear-Wave Elastography Performance in the Noninvasive Evaluation of Liver Fibrosis in Patients with Chronic Hepatitis B: Comparison with Serum Fibrosis Indexes

Purpose To investigate the value of two-dimensional (2D) shear-wave elastography (SWE) in the assessment of hepatic fibrosis in patients with chronic hepatitis B (CHB) and to compare the diagnostic performance of this modality with that of liver fibrosis indexes. Materials and Methods The ethics committee approved this study, and informed consent was obtained. From July 2015 to May 2016, 539 subjects who underwent partial hepatectomy were divided into groups according to the Scheuer system by using a resected liver specimen. All patients were examined with 2D SWE and underwent preoperative serologic testing to measure liver stiffness and values of serum fibrosis models, which were compared with histologic findings. Performance of noninvasive methods was determined for index (304 patients) and validation (155 patients) cohorts by using areas under the receiver operating characteristic curve (AUCs). Results For association with substantial fibrosis (≥S2), severe fibrosis (≥S3), and cirrhosis (S4) in the index cohort, the optimal cutoff values of liver stiffness were 7.6, 9.2, and 10.4 kPa, respectively, and AUC values were 0.97, 0.96, and 0.98, respectively. The 2D SWE findings, aspartate transaminase-to-platelet ratio index (APRI), fibrosis index based on the four factors (FIB-4), King's score, and Forns index significantly correlated with hepatic fibrosis stages (ρ = 0.88, ρ = 0.41, ρ = 0.40, ρ = 0.43 and ρ = 0.45, respectively; P < .05). The AUCs for APRI, FIB-4, King's score, and Forns index were 0.77, 0.73, 0.79, and 0.77, respectively, in the diagnosis of substantial fibrosis and 0.70, 0.71, 0.72, and 0.74, respectively, in the diagnosis of cirrhosis. In the validation cohort, AUCs of noninvasive methods used to assess different fibrosis stages did not significantly differ from those for the index cohort. AUCs of 2D SWE in the diagnosis of substantial fibrosis, severe fibrosis, and cirrhosis were 0.97, 0.97, and 0.98, respectively, which were significantly higher than those in serum models (P < .05). Conclusion The 2D SWE protocol could be used to predict substantial fibrosis, severe fibrosis, and cirrhosis in patients with CHB with notably higher diagnostic accuracy than that attained with serum fibrosis models. ^© RSNA, 2016.

Elastography of shear wave speed imaging for the evaluation of liver fibrosis: A meta-analysis

AIM

A meta-analysis was carried out to assess the accuracies of shear wave speed imaging (SWSI) in predicting significant fibrosis (stages F2-4) and cirrhosis (stage F4).

METHODS

A review was performed of relevant studies published until October 2015. A bivariate binomial model was used to combine the sensitivity, specificity, and the area under the summary receiver operating characteristic (AUC), and 95% confidence intervals were derived to indicate the diagnostic accuracy of imaging modalities.

RESULTS

In total, 10 studies with 2182 patients were included in the analysis. The sensitivity, specificity, and AUC (with 95% confidence intervals) of SWSI were: 0.84 (0.81-0.87), 0.83 (0.77-0.88), and 0.88 (0.85-0.90) for significant fibrosis, respectively; and 0.80 (0.66-0.89), 0.93 (0.88-0.96), and 0.95 (0.92-0.96) for cirrhosis, respectively. When SWSI was compared with well-evaluated transient elastography, the AUCs for the prediction of significant fibrosis were 0.93 and 0.86, respectively. The AUCs for the prediction of cirrhosis were both 0.94.

CONCLUSION

Shear wave speed imaging is a trustworthy tool for staging hepatic fibrosis, with a high combination of sensitivity and specificity. Compared with transient elastography, SWSI showed better diagnostic performance for the prediction of significant fibrosis.