Real‐time shear wave elastography (SWE) is a novel, noninvasive method to assess liver fibrosis by measuring liver stiffness. This single‐center study was conducted to assess the accuracy of SWE in ...patients with chronic hepatitis C (CHC), in comparison with transient elastography (TE), by using liver biopsy (LB) as the reference standard. Consecutive patients with CHC scheduled for LB by referring physicians were studied. One hundred and twenty‐one patients met inclusion criteria. On the same day, real‐time SWE using the ultrasound (US) system, Aixplorer (SuperSonic Imagine S.A., Aix‐en‐Provence, France), TE using FibroScan (Echosens, Paris, France), and US‐assisted LB were consecutively performed. Fibrosis was staged according to the METAVIR scoring system. Analyses of receiver operating characteristic (ROC) curve were performed to calculate optimal area under the ROC curve (AUROC) for F0‐F1 versus F2‐F4, F0‐ F2 versus F3‐F4, and F0‐F3 versus F4 for both real‐time SWE and TE. Liver stiffness values increased in parallel with degree of liver fibrosis, both with SWE and TE. AUROCs were 0.92 (95% confidence interval CI: 0.85‐0.96) for SWE and 0.84 (95% CI: 0.76‐0.90) for TE (P = 0.002), 0.98 (95% CI: 0.94‐1.00) for SWE and 0.96 (95% CI: 0.90‐0.99) for TE (P = 0.14), and 0.98 (95% CI: 0.93‐1.00) for SWE and 0.96 (95% CI: 0.91‐0.99) for TE (P = 0.48), when comparing F0‐F1 versus F2‐ F4, F0‐ F2 versus F3‐F4, and F0 ‐F3 versus F4, respectively. Conclusion: The results of this study show that real‐time SWE is more accurate than TE in assessing significant fibrosis (≥F2). With respect to TE, SWE has the advantage of imaging liver stiffness in real time while guided by a B‐mode image. Thus, the region of measurement can be guided with both anatomical and tissue stiffness information. (HEPATOLOGY 2012;56:2125–2133)
AIM:To estimate the validity of the point shear-wave elastography method by evaluating its reproducibility and accuracy for assessing liver stiffness.METHODS:This was a single-center,cross-sectional ...study.Consecutive patients with chronic viral hepatitis scheduled for liver biopsy(LB)(Group 1)and healthy volunteers(Group 2)were studied.In each subject 10 consecutive point shear-wave elastography(PSWE)measurements were performed using the iU22 ultrasound system(Philips Medical Systems,Bothell,WA,United States).Patients in Group 1 underwent PSWE,transient elastography(TE)using FibroScan(Echosens,Paris,France)and ultrasound-assisted LB.For the assessment of PSWE reproducibility two expert raters(rater 1 and rater 2)independently performed the examinations.The performance of PSWE was compared to that of TE using LB as a reference standard.Fibrosis was staged according to the METAVIR scoring system.Receiver operating characteristic curve analyses were performed to calculate the area under the receiver operating characteristic curve(AUC)for F≥2,F≥3and F=4.The intraobserver and interobserver reproducibility of PSWE were assessed by calculating Lin’s concordance correlation coefficient.RESULTS:To assess the performance of PSWE,134consecutive patients in Group 1 were studied.The median values of PSWE and TE(in kilopascals)were 4.7(IQR=3.8-5.4)and 5.5(IQR=4.7-6.5),respectively,in patients at the F0-F1 stage and 3.5(IQR=3.2-4.0)and 4.4(IQR=3.5-4.9),respectively,in the healthy volunteers in Group 2(P<10-5).In the univariate analysis,the PSWE and TE values showed a high correlation with the fibrosis stage;low correlations with the degree of necroinflammation,aspartate aminotransferase and gamma-glutamyl transferase(GGT);and a moderate negative correlation with the platelet count.A multiple regression analysis confirmed the correlations of both PSWE and TE with fibrosis stage and GGT but not with any other variables.The following AUC values were found:0.80(0.71-0.87)for PSWE and 0.82(0.73-0.89)for TE(P=0.42);0.88(0.80-0.94)for PSWE and 0.95(0.88-0.98)for TE(P=0.06);and 0.95(0.89-0.99)for PSWE and 0.92(0.85-0.97)for TE(P=0.30)for F≥2,F≥3 and F=4,respectively.To assess PSWE reproducibility,116 subjects were studied,including 47consecutive patients scheduled for LB(Group 1)and 69 consecutive healthy volunteers(Group 2).The intraobserver agreement ranged from 0.83(95%CI:0.79-0.88)to 0.96(95%CI:0.95-0.97)for rater 1 and from 0.84(95%CI:0.79-0.88)to 0.96(95%CI:0.95-0.97)for rater 2.The interobserver agreement yielded values from0.83(95%CI:0.78-0.88)to 0.93(95%CI:0.91-0.95).CONCLUSION:PSWE is a reproducible method for assessing liver stiffness,and it compares with TE.Compared with patients with nonsignificant fibrosis,healthy volunteers showed significantly lower values.
Objectives
The main aim was to assess the performance and cutoff value for the detection of liver steatosis (grade S > 0) with the Attenuation Imaging–Penetration (ATI‐Pen) algorithm available on the ...Aplio i‐series ultrasound systems (Canon Medical Systems, Otawara, Japan). The magnetic resonance imaging–derived proton density fat fraction (MRI‐PDFF) was used as the reference standard. Secondary aims were to compare the results to those obtained with the previous ATI algorithm (Attenuation Imaging–General ATI‐Gen) and with the controlled attenuation parameter (CAP) and to generate a regression equation between ATI‐Pen and ATI‐Gen values.
Methods
Consecutive adult patients potentially at risk of liver steatosis were prospectively enrolled. Each patient underwent ultrasound quantification of liver steatosis with ATI‐Pen and ATI‐Gen and a CAP assessment with the FibroScan system (Echosens, Paris, France). The MRI‐PDFF evaluation was performed within a week. The correlations between ATI‐Pen, ATI‐Gen, the CAP, and the MRI‐PDFF were analyzed with the Pearson rank correlation coefficient. The diagnostic performance of ATI‐Pen, ATI‐Gen, and the CAP was assessed with receiver operating characteristic curves and an area under the receiver operating characteristic curve (AUROC) analysis.
Results
Seventy‐two individuals (31 male and 41 female) were enrolled. Correlation coefficients of ATI‐Pen, ATI‐Gen, and the CAP with the MRI‐PDFF were 0.78, 0.83, and 0.58, respectively. The AUROCs of ATI‐Pen, ATI‐Gen, and the CAP for detecting steatosis (S > 0) were 0.90 (95% confidence interval, 0.81–0.96), 0.92 (0.82–0.98), and 0.85 (0.74–0.92), and the cutoffs were greater than 0.69 dB/cm/MHz, greater than 0.62 dB/cm/MHz, and greater than 273 dB/m. The regression equation between ATI‐Pen and ATI‐Gen was ATI‐Pen = 0.88 ATI‐Gen + 0.13.
Conclusions
Attenuation Imaging is a reliable tool for detecting liver steatosis, showing an excellent correlation with the MRI‐PDFF and high performance with AUROCs of 0.90 or higher.
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Two‐dimensional shear wave elastography (2D‐SWE) has proven to be efficient for the evaluation of liver fibrosis in small to moderate‐sized clinical trials. We aimed at running a larger‐scale ...meta‐analysis of individual data. Centers which have worked with Aixplorer ultrasound equipment were contacted to share their data. Retrospective statistical analysis used direct and paired receiver operating characteristic and area under the receiver operating characteristic curve (AUROC) analyses, accounting for random effects. Data on both 2D‐SWE and liver biopsy were available for 1,134 patients from 13 sites, as well as on successful transient elastography in 665 patients. Most patients had chronic hepatitis C (n = 379), hepatitis B (n = 400), or nonalcoholic fatty liver disease (n = 156). AUROCs of 2D‐SWE in patients with hepatitis C, hepatitis B, and nonalcoholic fatty liver disease were 86.3%, 90.6%, and 85.5% for diagnosing significant fibrosis and 92.9%, 95.5%, and 91.7% for diagnosing cirrhosis, respectively. The AUROC of 2D‐SWE was 0.022‐0.084 (95% confidence interval) larger than the AUROC of transient elastography for diagnosing significant fibrosis (P = 0.001) and 0.003‐0.034 for diagnosing cirrhosis (P = 0.022) in all patients. This difference was strongest in hepatitis B patients. Conclusion: 2D‐SWE has good to excellent performance for the noninvasive staging of liver fibrosis in patients with hepatitis B; further prospective studies are needed for head‐to‐head comparison between 2D‐SWE and other imaging modalities to establish disease‐specific appropriate cutoff points for assessment of fibrosis stage. (Hepatology 2018;67:260‐272).
Shear Wave Elastography for Evaluation of Liver Fibrosis Ferraioli, Giovanna; Parekh, Parth; Levitov, Alexander B. ...
Journal of ultrasound in medicine,
February 2014, 2014-Feb, 2014-02-00, 20140201, Letnik:
33, Številka:
2
Journal Article
Recenzirano
Odprti dostop
The prognosis and management of chronic viral hepatitis mainly depend on the extent of liver fibrosis, particularly in chronic hepatitis C. Liver histologic analysis is still considered the reference ...standard in the assessment of liver fibrosis despite the interobserver and interobserver variability in staging and some morbidity and mortality risks. Thus, noninvasive methods for assessing liver fibrosis are of great clinical interest. In the last decade, ultrasound‐based techniques to estimate the stage of liver fibrosis have become commercially available. They all have the capability to noninvasively evaluate differences in the elastic properties of soft tissues by measuring tissue behavior when a mechanical stress is applied. Shear wave elastography relies on the generation of shear waves determined by the displacement of tissues induced by the force of a focused ultrasound beam or by an external push. This article reviews the results that have been obtained with shear wave elastography for assessment of liver fibrosis.
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).
Abstract Objective To evaluate the reproducibility of real-time shear wave elastography in assessing liver elasticity in healthy volunteers. Methods Forty-two volunteers were studied in day 1. Shear ...wave elastography studies were performed by using the ultrasound system Aixplorer™ (SuperSonic Imagine S.A., Aix-en-Provence, France) with a convex broadband probe. Measurements were carried by two operators, an expert (operator 1) and a novice (operator 2). Examinations were performed on the right lobe of the liver. Each operator performed 10 consecutive measurements in each volunteer. In a subset of volunteers ( n = 18) measurements were performed twice on two different days (day 1 and day 2). Intraobserver and interobserver agreement were assessed by intraclass correlation coefficient. Results Intraobserver agreement between measurements performed in the same subject in the same day (day 1 or day 2) showed intraclass correlation coefficient values of 0.95 (95% confidence interval, 0.93–0.98) and 0.93 (95% confidence interval, 0.90–0.96) for operator 1 and operator 2, respectively. Intraobserver agreement between measurements performed in the same subject in different days showed intraclass correlation coefficient values of 0.84 (95% confidence interval, 0.69–0.98) and 0.65 (95% confidence interval, 0.39–0.91) for operator 1 and operator 2, respectively. Interobserver agreement was 0.88 (95% confidence interval, 0.82–0.94). Conclusions The results of this study show that shear wave elastography is a reliable and reproducible noninvasive method for the assessment of liver elasticity. Expert operator had higher reproducibility of measurements over time than novice operator.
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.
The primary aim of this study was to determine the inter-system variability of liver stiffness measurements (LSMs) in patients with varying degrees of liver stiffness. The secondary aim was to ...determine the inter-observer variability of measurements.
21 individuals affected by chronic hepatitis C and 5 healthy individuals were prospectively enrolled. The assessment of LSMs was performed using six ultrasound (US) systems, four of which with point shear wave elastography (p-SWE) and two with 2 D shear wave elastography (2D-SWE) systems. The Fibroscan (Echosens, France) was used as the reference standard. Four observers performed the measurements in pairs (A-B, C-D). The agreement between different observers or methods was calculated using Lin's concordance correlation coefficient. The Bland-Altman limits of agreement (LOA) were calculated as well.
There was agreement above 0.80 for all pairs of systems. The mean difference between the values of the systems with 2D-SWE technique was 1.54 kPa, whereas the maximum mean difference between the values of three out of four systems with the pSWE technique was 0.79 kPa. The intra-patient concordance for all systems was 0.89 (95 % CI: 0.83 - 0.94). Inter-observer agreement was 0.96 (95 % CI: 0.94 - 0.98) for the pair of observers A-B and 0.93 (95 % CI: 0.89 - 0.96) for the pair of observers C-D.
The results of this study show that the agreement between LSMs performed with different US systems is good to excellent and the overall inter-observer agreement in "ideal conditions" is above 0.90 in expert hands.
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