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The World Federation for Ultrasound in Medicine and Biology (WFUMB) has promoted the development of this document on multiparametric ultrasound. Part 2 is a guidance on the use of the available tools for the quantification of liver fat content with ultrasound. These are attenuation coefficient, backscatter coefficient, and speed of sound. All of them use the raw data of the ultrasound beam to estimate liver fat content. This guidance has the aim of helping the reader in understanding how they work and interpret the results. Confounding factors are discussed and a standardized protocol for measurement acquisition is suggested to mitigate them. The recommendations were based on published studies and experts' opinion but were not formally graded because the body of evidence remained low at the time of drafting this document., Competing Interests: Conflict of interest G.F. has received a speaker honorarium from Canon Medical Systems, Fujifilm Healthcare, Mindray Medical Imaging, Philips Ultrasound, Siemens Healthineers. She has served on advisory boards for Philips Healthcare and Siemens Healthineers and her university has received ultrasound equipment grants and unrestricted research grants from Canon Medical Systems, Esaote SpA, Fujifilm Medical Systems, Philips Ultrasound. She receives royalties from Elsevier Publisher. R.G.B. has received a speaker honorarium from Canon Medical systems, Philips Ultrasound, Siemens Healthineers, Mindray, Samsung Ultrasound, Hologic Ultrasound. He has received research grants from Philips Ultrasound, Canon Ultrasound, Canon MRI, Samsung, Siemens Healthineers, Hologic, Mindray and equipment grants from Canon Medical Systems, Philips Ultrasound, Mindray, Samsung Ultrasound and Siemens Healthineers. He is on the advisory board of Lantheus Medical. He receives royalties from Thieme Publishers and Elsevier Publisher. A.B. is consultant for Boehringer-Ingelheim and has received speaker honoraria from GE Healthcare and Hologic Ultrasound. She has received research ultrasound equipment support from GE Healthcare. I.S. has received speaker fees from Siemens Healthineers, General Electric, Samsung Ultrasound, Canon Medical Systems. V.W.W. served as a consultant or advisory board member for AbbVie, Boehringer Ingelheim, Echosens, Gilead Sciences, Intercept, Inventiva, Novo Nordisk, Pfizer, Sagimet Biosciences, TARGET PharmaSolutions, and Visirna; and a speaker for Abbott, AbbVie, Gilead Sciences, Novo Nordisk, Unilab. He has received a research grant from Gilead Sciences and is a co-founder of Illuminatio Medical Technology. T.R. received grant support from Abbvie, Boehringer Ingelheim, Gilead, Intercept/Advanz Pharma, MSD, Myr Pharmaceuticals, Philips Healthcare, Pliant, Siemens and W. L. Gore & Associates; speaking honoraria from Abbvie, Gilead, Intercept/Advanz Pharma, Roche, MSD, W. L. Gore & Associates; consulting/advisory board fee from Abbvie, Astra Zeneca, Bayer, Boehringer Ingelheim, Gilead, Intercept/Advanz Pharma, MSD, Resolution Therapeutics, Siemens; and travel support from Abbvie, Boehringer Ingelheim, Dr. Falk Pharma, Gilead and Roche. T.K. has received speaker honoraria from Echosens, Falk Foundation and Jazz Pharmaceuticals. He has served on advisory boards for Echosens and his university has received ultrasound equipment and unrestricted research grants from Canon Medical Systems and Echosens. M.T. has received a speaker honorarium from Siemens Healthcare, Echosens, Norgine, Madrigal, Takeda, and Tillotts Pharma. Advisory fee from Boehringer Ingelheim, AstraZeneca, GSK. Co-founder and board member of Evido. Board member for Alcohol & Society (non-governmental organisation). A.C.C. has received speaker honorarium from Novo Nordisk. O.T.A. has served as a consultant or adviser to Novo Nordisk, Resonance Health, Norgine and Sun Pharma. He has received research ultrasound equipment support from Canon Medical Systems. L.C. has served as a consultant for Boston Pharmaceuticals, Echosens, GSK, Madrigal, MSD, Novo Nordisk, Pfizer, Sagimet and Siemens Healthineers; and lecture fees from Echosens, Gilead, Inventiva, Madrigal and Novo Nordisk. C.F.D. has received speaker honorarium from AbbVie, Bracco, Falk Foundation, Fujifilm Healthcare, GE Healthcare, Janssen, Mindray Medical Imaging, Olympus, Pentax, Siemens Healthcare, Sonoscape. H.I. has received research grants from Canon Medical Systems and GE Healthcare. She has received research ultrasound equipment support from Canon Medical Systems. D.H.L. has received research grants and speaker honorarium from Canon Medical Systems. W.K. has received speaker honorarium from Novo Nordisk, Eaisi, Roche. C.P.O. has been a consultant or participant in clinical trials for NovoNordisk, Pfizer, Inventiva, Astra-Zeneca, Boehringer Ingelheim. S.K.S. declares no conflict of interest., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

The World Federation for Ultrasound in Medicine and Biology (WFUMB) endorsed the development of this document on multiparametric ultrasound. Part 1 is an update to the WFUMB Liver Elastography Guidelines Update released in 2018 and provides new evidence on the role of ultrasound elastography in chronic liver disease. The recommendations in this update were made and graded using the Oxford classification, including level of evidence (LoE), grade of recommendation (GoR) and proportion of agreement (Oxford Centre for Evidence-Based Medicine [OCEBM] 2009). The guidelines are clinically oriented, and the role of shear wave elastography in both fibrosis staging and prognostication in different etiologies of liver disease is discussed, highlighting advantages and limitations. A comprehensive section is devoted to the assessment of portal hypertension, with specific recommendations for the interpretation of liver and spleen stiffness measurements in this setting., Competing Interests: Conflict of interest G.F. has received a speaker honorarium from Canon Medical Systems, Fujifilm Healthcare, Mindray Medical Imaging, Philips Ultrasound and Siemens Healthineers. She has served on advisory boards for Philips Healthcare and Siemens Healthineers, and her university has received ultrasound equipment grants and unrestricted research grants from Canon Medical Systems, Esaote SpA, Fujifilm Medical Systems and Philips Ultrasound. She receives royalties from Elsevier. R.G.B. has received a speaker honorarium from Canon Medical systems, Philips Ultrasound, Siemens Healthineers, Mindray, Samsung Ultrasound and Hologic Ultrasound. He has received research grants from Philips Ultrasound, Canon Ultrasound, Canon MRI, Samsung, Siemens Healthineers, Hologic and Mindray, and equipment grants from Canon Medical Systems, Philips Ultrasound, Mindray, Samsung Ultrasound and Siemens Healthineers. He is on the advisory board of Lantheus Medical. He receives royalties from Thieme and Elsevier. A.B. is consultant for Boehringer–Ingelheim and has received speaker honoraria from GE Healthcare and Hologic Ultrasound. She has received research ultrasound equipment support from GE Healthcare. I.S. has received speaker fees from Siemens Healthineers, General Electric, Samsung Ultrasound and Canon Medical Systems. V.W.S.W. served as a consultant or advisory board member for AbbVie, Boehringer Ingelheim, Echosens, Gilead Sciences, Intercept, Inventiva, Novo Nordisk, Pfizer, Sagimet Biosciences, TARGET PharmaSolutions and Visirna, and as a speaker for Abbott, AbbVie, Gilead Sciences, Novo Nordisk and Unilab. He has received a research grant from Gilead Sciences and is a co-founder of Illuminatio Medical Technology. T.R. received grant support from Abbvie, Boehringer Ingelheim, Gilead, Intercept/Advanz Pharma, MSD, Myr Pharmaceuticals, Philips Healthcare, Pliant, Siemens and W. L. Gore & Associates; speaking honoraria from Abbvie, Gilead, Intercept/Advanz Pharma, Roche, MSD and W. L. Gore & Associates; a consulting/advisory board fee from Abbvie, Astra Zeneca, Bayer, Boehringer Ingelheim, Gilead, Intercept/Advanz Pharma, MSD, Resolution Therapeutics and Siemens; and travel support from Abbvie, Boehringer Ingelheim, Dr. Falk Pharma, Gilead and Roche. T.K. has received speaker honoraria from Echosens, Falk Foundation and Jazz Pharmaceuticals, and has served on advisory boards for Echosens and his university has received ultrasound equipment and unrestricted research grants from Canon Medical Systems and Echosens. M.T. has received a speaker honorarium from Siemens Healthcare, Echosens, Norgine, Madrigal, Takeda and Tillotts Pharma and an advisory fee from Boehringer Ingelheim, AstraZeneca and GSK; she is a co-founder and board member of Evido and is a board member for Alcohol & Society (non-governmental organization). ACC has received speaker honorarium from Novo Nordisk. O.T.A. has served as a consultant or adviser to Novo Nordisk, Resonance Health, Norgine and Sun Pharma; he has received research ultrasound equipment support from Canon Medical Systems. L.C. has received consulting fees from Boston Pharmaceutical, Echosens, Gilead, GSK, Madrigal, MSD, Novo Nordisk, Pfizer, Sagimet and Siemens Healthineers, and speaker fees from Echosens, Gilead, Inventiva, Madrigal and Novo Nordisk. C.F.D. has received a speaker honorarium from AbbVie, Bracco, Falk Foundation, Fujifilm Healthcare, GE Healthcare, Janssen, Mindray Medical Imaging, Olympus, Pentax, Siemens Healthcare and Sonoscape. H.I. has received research grants from Canon Medical Systems and GE Healthcare and research ultrasound equipment support from Canon Medical Systems. D.H.L. has received research grants and a speaker honorarium from Canon Medical Systems. W.K. has received a speaker honorarium from Novo Nordisk, Eaisi and Roche. C.P.O. has been a consultant or participant in clinical trials for NovoNordisk, Pfizer, Inventiva, Astra-Zeneca and Boehringer Ingelheim. S.K.S. declares no conflicts of interest., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

We aimed to investigate the diagnostic performance of new 2-D shear-wave elastography (SWE) with propagation maps and attenuation imaging (ATI) for quantification of fibrosis and steatosis in non-alcoholic fatty liver disease (NAFLD). Consecutive patients with NAFLD and healthy volunteers underwent liver stiffness measurement and steatosis quantification by means of vibration-controlled transient elastography coupled with the controlled attenuation parameter as the reference and by 2-D shear-wave elastography (2-D-SWE) with propagation maps and ATI as the investigational methods. We included 232 participants (164 in the NAFLD group and 68 in the healthy control group): 51.7%/49.3% women/men; mean age, 54.2 ± 15.2 y; mean body mass index, 29.4 ± 6.5 kg/m 2 . Significant correlations were found between 2-D-SWE and vibration-controlled transient elastography (r = 0.71, p < 0.0001) and between ATI and the controlled attenuation parameter (r = 0.72, p < 0.0001). NAFLD-specific 2-D-SWE liver stiffness measurement cutoffs were as follows-F ≥ 2: 7.9 kPa (area under the curve [AUC] = 0.91); F ≥ 3: 10 kPa (AUC = 0.92); and F = 4: 11.4 kPa (AUC = 0.95). For steatosis, the best cutoffs by ATI were as follows-S1 = 0.73 dB/cm/MHz (AUC = 0.86); S2 = 0.76 dB/cm/MHz (AUC = 0.86); and S3 = 0.80 dB/cm/MHz (AUC = 0.83). According to Baveno VI criteria, the optimal 2-D-SWE liver stiffness measurement for diagnosing liver cirrhosis is 15.5 kPa (AUC = 0.94), and for ruling out compensated advanced chronic liver disease it is 9.2 kPa (AUC = 0.92). To conclude, 2-D-SWE with propagation maps and ATI is reliable for quantification of liver fibrosis and steatosis in patients with NAFLD., (Copyright © 2021 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.)

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., (Copyright © 2021 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.)

The study evaluates the utility of spleen (SS) and liver stiffness (LS) associated with spleen size (SSZ) as non-invasive markers for predicting high-risk varices (HRV). One hundred thirty-two patients with compensated liver cirrhosis who underwent abdominal ultrasound SS (SSM) and LS measurements (LSM) using a 2-D shear wave elastography (2-D-SWE) technique from General Electric and upper endoscopy were included. Similar rates of reliable SSM and LSM were obtained (95.4% and 97.7% respectively); therefore, 124 patients were included in the final analysis. The optimal cutoff values for SS, LS and SSZ for predicting HRV were 13.2 kPa (area under the receiver operating characteristic curve [AUROC] = 0.84), 12.1 kPa (AUROC = 0.86) and 12.9 cm (AUROC = 0.71), respectively. Including these factors in multiple regression analysis, we obtained the scores for predicting HRV: 0.053 × SS + 0.054 × LS + 0.059 × SSZ - 1.84. The score's optimal cutoff value for predicting HRV was >0.34 (AUROC = 0.93). By comparing the AUROC's, the score including SSZ, SSM and LSM performed better than each independent factor for predicting HRV (p = 0.0091; p = 0.0341; p < 0.0001)., Competing Interests: Conflict of interest disclosure The authors have no conflicts of interest to declare., (Copyright © 2020 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.)

The study compared the diagnostic performance of two shear-wave elastography techniques, elastography point quantification (ElastPQ) and 2-D shear-wave elastography by General Electric (2-D-SWE.GE), for the non-invasive assessment of liver fibrosis in a cohort of patients with chronic hepatitis C virus (HCV) infection, using transient elastography (TE) as the reference method. There was no significant difference between the feasibility rates of TE, ElastPQ and 2-D-SWE.GE (p = 0.507). A good correlation was found between the liver stiffness (LS) values obtained using the two elastographic methods (r = 0.78). The mean LS values obtained using the ElastPQ technique were significantly higher than those obtained using 2-D-SWE.GE (12.1 ± 7.3 kPa vs. 10.4 ± 4.0 kPa, p < 0.0001). Pairwise comparisons of receiver operator characteristics curves between 2-D-SWE.GE and ElastPQ have shown that there are no significant differences in their performance for staging F ≥ 2 fibrosis (p = 0.89), F ≥ 3 fibrosis (p = 0.76) and F = 4 fibrosis (p = 0.86) in patients with chronic HCV infection., Competing Interests: Conflict of interest disclosure The authors declare no competing interests., (Copyright © 2020 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.)

The present, updated document describes the fourth iteration of recommendations for the hepatic use of contrast-enhanced ultrasound, first initiated in 2004 by the European Federation of Societies for Ultrasound in Medicine and Biology. The previous updated editions of the guidelines reflected changes in the available contrast agents and updated the guidelines not only for hepatic but also for non-hepatic applications. The 2012 guideline requires updating as, previously, the differences in the contrast agents were not precisely described and the differences in contrast phases as well as handling were not clearly indicated. In addition, more evidence has been published for all contrast agents. The update also reflects the most recent developments in contrast agents, including U.S. Food and Drug Administration approval and the extensive Asian experience, to produce a truly international perspective. These guidelines and recommendations provide general advice on the use of ultrasound contrast agents (UCAs) and are intended to create standard protocols for the use and administration of UCAs in liver applications on an international basis to improve the management of patients., (Copyright © 2020 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.)

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., (Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.)

The aim of the study described here was to evaluate the reproducibility of a new shear-wave elastography (SWE) technique, 2-D SWE.GE, and the impact of ultrasound experience in acquiring reliable measurements, as no official recommendations are available for this system. Elastographic measurements (EMs) were obtained in 60 patients using 2-D-SWE with the GE Logiq E9. Three examiners with different levels of experience in ultrasound-based elastography performed 10 valid EMs on each subject: a novice (C.P.) who had no experience in liver elastography and had performed fewer than 50 ultrasound examinations; an elastography expert (A.M.S.) who had more than 1 y of liver elastographic experience in four elastographic methods and had performed more than 1000 ultrasonography examinations; and an ultrasound expert (T.M.) who had no experience in liver elastography and had performed more than 1000 ultrasound examinations. Medians and interquartile ranges were calculated (m/s). We used the inter-class correlation coefficient and Bland-Altman plots with 95% lower and upper limits of agreement to assess the inter- and intra-observer reproducibility of 2-D-SWE.GE measurements. The final study group included 60 patients, 56.7% women and 43.3% men, with a mean age of 33.08 ± 13.83 y and mean body mass index of 22.85 ± 4.04 kg/m 2 . In this group, 73.3% were healthy volunteers and 26.7% had compensated liver cirrhosis. We did not find significant differences between EMs taken by the examiners overall and across study groups. The overall agreement between examiners was excellent: 0.915 (95% confidence interval [CI]: 0.870-0.946). The agreement between the novice and the experienced examiners, respectively, was good to excellent (novice and ultrasound expert: 0.908, 95% CI: 0.846-0.945; novice and elastography expert: 0.885, 95% CI: 0.808-0.931). The intra-observer reproducibility for each of the examiners was excellent; however, the inter-class correlation coefficients were higher for the examiners more experienced in elastography: 0.936 (95% CI: 0.896-0.963) versus 0.966 (95% CI: 0.943-0.980) versus 0.984 (95% CI: 0. 973-0.991). The good ICCs for the median values indicate that 2-D-SWE.GE is a reproducible method. Ultrasound experience did not significantly influence the results., (Copyright © 2018 World Federation for Ultrasound in Medicine and Biology. Published by Elsevier Inc. All rights reserved.)

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., (Copyright © 2018 World Federation for Ultrasound in Medicine and Biology. Published by Elsevier Inc. All rights reserved.)

In previous studies of acoustic radiation force impulse (ARFI) elastography, using Virtual Touch tissue quantification (VTQ) (Siemens Acuson S2000), it was reported that the measurement of renal shear wave speed in patients with chronic kidney disease (CKD) is not influenced exclusively by renal fibrosis. The purpose of the present study was to analyze the role of VTQ in patients with diabetic kidney disease, considered the main cause of CKD. The study group included 164 patients: 80 patients with diabetic kidney disease (DKD) and 84 without renal disease or diabetes mellitus. In each subject in lateral decubitus, five valid VTQ measurements were performed in each kidney and a median value was calculated, the result being expressed in meters/second. The following means of the median values were obtained In DKD patients, the means of the median values were for VTQ right kidney, 2.21 ± 0.71 m/s, and for VTQ left kidney, 2.13 ± 0.72 m/s, whereas in the normal controls statistically significant higher values were obtained: 2.58 ± 0.78 m/s for VTQ right kidney (p = 0.0017) and 2.46 ± 0.81 m/s for VTQ left kidney (p = 0.006). Patients with an estimated glomerular filtration rate (eGFR) >60 mL/min (DKD stages 1 and 2 together with normal controls) had a significantly higher kidney shear wave speed compared with patients with an eGFR <60 mL/min (2.53 m/s vs. 2.09 m/s, p < 0.05). In the DKD group, there was a significant correlation between eGFR and VTQ levels for the right kidney (r = 0.28, p = 0.04). There was no correlation of VTQ values with proteinuria level, stage of diabetic retinopathy or glycated hemoglobin. Our study indicates that shear wave speed values in patients with diabetic kidney disease and eGFRs <60 mL/min are significantly lower compared with those of patients with eGFRs >60 mL/min (either normal controls or diabetic patients with DKD stages 1 and 2), and values decrease with the decrease in eGFR. However, proteinuria, diabetic retinopathy and glycated hemoglobin have no influence on VTQ., (Copyright © 2017 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.)

The breast section of these Guidelines and Recommendations for Elastography produced under the auspices of the World Federation of Ultrasound in Medicine and Biology (WFUMB) assesses the clinically used applications of all forms of elastography used in breast imaging. The literature on various breast elastography techniques is reviewed, and recommendations are made on evidence-based results. Practical advice is given on how to perform and interpret breast elastography for optimal results, with emphasis placed on avoiding pitfalls. Artifacts are reviewed, and the clinical utility of some artifacts is discussed. Both strain and shear wave techniques have been shown to be highly accurate in characterizing breast lesions as benign or malignant. The relationship between the various techniques is discussed, and recommended interpretation based on a BI-RADS-like malignancy probability scale is provided. This document is intended to be used as a reference and to guide clinical users in a practical way., (Copyright © 2015. Published by Elsevier Inc.)

Conventional diagnostic ultrasound images of the anatomy (as opposed to blood flow) reveal differences in the acoustic properties of soft tissues (mainly echogenicity but also, to some extent, attenuation), whereas ultrasound-based elasticity images are able to reveal the differences in the elastic properties of soft tissues (e.g., elasticity and viscosity). The benefit of elasticity imaging lies in the fact that many soft tissues can share similar ultrasonic echogenicities but may have different mechanical properties that can be used to clearly visualize normal anatomy and delineate pathologic lesions. Typically, all elasticity measurement and imaging methods introduce a mechanical excitation and monitor the resulting tissue response. Some of the most widely available commercial elasticity imaging methods are 'quasi-static' and use external tissue compression to generate images of the resulting tissue strain (or deformation). In addition, many manufacturers now provide shear wave imaging and measurement methods, which deliver stiffness images based upon the shear wave propagation speed. The goal of this review is to describe the fundamental physics and the associated terminology underlying these technologies. We have included a questions and answers section, an extensive appendix, and a glossary of terms in this manuscript. We have also endeavored to ensure that the terminology and descriptions, although not identical, are broadly compatible across the WFUMB and EFSUMB sets of guidelines on elastography (Bamber et al. 2013; Cosgrove et al. 2013)., (Copyright © 2015. Published by Elsevier Inc.)

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., (Copyright © 2015. Published by Elsevier Inc.)

Our aim was to assess kidney shear wave speed by means of acoustic radiation force impulse (ARFI) elastography in patients without kidney pathology ("normal" patients) and to identify the factors that influence it. We analyzed 91 "normal" patients in whom kidney shear wave speed was assessed by means of ARFI elastography. Five valid ARFI elastographic measurements were obtained in all "normal" patients in both kidneys. In univariate analysis, age (r = -0.370, p = 0.003), gender (female vs. male, r = -0.305, p = 0.003) and measurement depth (r = -0.285, p = 0.01) were significantly correlated with kidney shear wave speed values assessed by ARFI elastography, whereas body mass index, kidney length and renal parenchyma thickness were not correlated. In multivariate analysis, only age (p = 0.006) and gender (p = 0.03) were significantly correlated with kidney shear wave speed values. In conclusion, kidney shear wave speed values assessed by ARFI elastography in "normal" patients are influenced mainly by age and gender and less by measurement depth., (Copyright © 2015 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.)

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., (Copyright © 2013 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.)

Our study compared three elastographic methods--transient elastography (TE), acoustic radiation force impulse (ARFI) imaging and supersonic shear imaging (SSI)--with respect to the feasibility of their use in liver fibrosis evaluation. We also compared the performance of ARFI imaging and SSI, with TE as the reference method. The study included 332 patients, with or without hepatopathies, in which liver stiffness was evaluated using TE, ARFI and SSI. Reliable measurements were defined as a median value of 10 (TE, ARFI imaging) or 5 (SSI) liver stiffness measurements with a success rate ≥60% and an interquartile range interval <30%. A significantly higher percentage of reliable measurements were obtained using ARFI than by using TE and SSI: 92.1% versus 72.2% (p < 0.0001) and 92.1% versus 71.3% (p < 0.0001). Higher body mass index and older age were significantly associated with inability to obtain reliable measurements of liver stiffness using TE and SSI. In 55.4% of patients, reliable liver stiffness measurements were obtained using all three elastographic methods, and ARFI imaging and TE were similarly accurate in diagnosing significant fibrosis and cirrhosis, with TE as the reference method., (Copyright © 2013 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.)

We used supersonic shear imaging to determine the liver stiffness (LS) values of 82 patients without known liver pathology and studied the factors that influence these measurements. Five LS measurements were made in each subject, and the median value, expressed in kilopascals, was calculated. Reliable LS measurements were obtained in 84.5% of patients. Higher body mass index and older age were associated with failure to obtain reliable measurements. The mean value of LS measurements determined by SSI in our cohort of patients without known liver pathology was 6 ± 1.4 kPa. The mean LS measurements determined by SSI for men were significantly higher than those for women; body mass index did not significantly influence SSI measurements. Thus, 6 kPa is the mean SSI value in patients without known liver pathology, with higher values being obtained in men., (Copyright © 2013 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.)

The present study assessed the influence of food intake on acoustic radiation force impulse elastography (ARFI) measurements. Seventy-three healthy volunteers were included: 57 subjects in the study group (on whom ARFI measurements were performed first in fasting condition, followed by measurements made 1h and 3h after food intake); and 16 subjects in the control group (on whom ARFI measurements were performed 3 times during a 3-h interval without eating). All subjects included in the study group received the same standard solid meal. In the study group, the mean liver stiffness (LS) values by ARFI increased significantly 1 h after food intake (1.51 ± 0.40 m/s vs. 1.27 ± 0.23, p = 0.003), but 3 h after the meal the differences were no longer significant (1.46 ± 0.51 vs. 1.27 ± 0.23, p = 0.06). In the control group, the mean LS values were similar in all 3 measurements. In conclusion, food intake significantly increased the LS values, thus ARFI measurements should be performed in fasting conditions., (Copyright © 2013 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.)

Our study tried to identify the factors associated with discordance between liver stiffness values assessed by acoustic radiation force impulse (ARFI) elastography and histologic fibrosis in 106 chronic hepatitis C patients. Liver biopsy (LB) and ARFI measurements were performed in the same session. A discordance of at least two stages of fibrosis in the Metavir scoring system between ARFI results and LB was defined as significant. The performance of ARFI elastography was assessed using the following cut-offs: F1-1.19 m/s, F2-1.34 m/s, F3-1.55 m/s and F4-1.80 m/s. Discordance of at least two stages of fibrosis between ARFI results and histologic assessment were observed in 31.7% of the patients. In an univariate analysis, female sex (p = 0.004), interquartile range interval (IQR) ≥30% (p = 0.04), high alanine aminotransferases (p = 0.008) and high aspartate aminotransferases levels (p = 0.003) were associated with discordances. In a multivariate analysis, the female sex (p = 0.006) and IQR ≥30% (p = 0.004) were associated with discordances. Therefore, IQR parameter should be used for ARFI measurements., (Copyright © 2013 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.)

Our aim was to compare liver stiffness (LS) measurements by means of acoustic radiation force impulse (ARFI) elastography and transient elastography (TE) in patients with chronic hepatitis B and C, according to the severity of fibrosis. We also compared the correlation strength of ARFI and TE measurements with liver fibrosis. We included 53 patients with hepatitis B and 107 with hepatitis C in which liver biopsy, ARFI and TE measurements were performed in the same session. The mean LS values measured with ARFI were similar in patients with chronic hepatitis B and C and depended on the stage of fibrosis. The correlation strength of LS measurements by ARFI and by TE with fibrosis was similar in chronic hepatitis B and C patients. In conclusion, for the same stage of fibrosis, the mean LS values by ARFI were similar in patients with chronic hepatitis B and C. ARFI had similar predictive value with TE in both chronic viral hepatitis., (Copyright © 2012 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.)

Our study assessed acoustic radiation force impulse (ARFI) reproducibility and the factors influencing it. The intra- and interoperator reproducibility were studied in 33 and 58 patients, respectively. Intraclass correlation coefficient (ICC) was used to assess ARFI reproducibility. The overall intraoperator agreement was better than the interoperator one: ICC 0.90 vs. ICC 0.81. The correlation of repeated ARFI measurements was higher, but not significantly so, in cases in which intraoperator reproducibility was assessed compared with the ones in which interoperator reproducibility was studied: r = 0.848 vs. r = 0.694 (p = 0.08). For both intra- and interoperator reproducibility, the ICCs were smaller in women vs. men (0.88 vs. 0.91 and 0.67 vs. 0.86, respectively), in patients with high body mass index (BMI) ≥25 kg/m² vs. <25 kg/m² (0.88 vs. 0.91 and 0.79 vs. 0.82, respectively), in patients with ascites vs. no ascites (0.80 vs. 0.93 and 0.78 vs. 0.84, respectively) and in noncirrhotic vs. cirrhotic patients (0.77 vs. 0.82 and 0.70 vs. 0.83, respectively)., (Copyright © 2012 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.)