How does liver steatosis affect diagnostic performance of 2D-SWE.SSI: assessment from aspects of steatosis degree and pathological types

Understanding confounding factors allows for accurate interpretation of liver stiffness measurements by ElastQ, a novel 2D shear wave elastography technique

PURPOSE

Liver stiffness measurement (LSM) using vibration-controlled transient elastography (VCTE) or two-dimensional shear wave elastography (2D-SWE) is recommended to assess the risk of liver fibrosis and advanced chronic liver disease. Even though both techniques measure liver stiffness, their numerical results often diverge. Confounders and reliability criteria for 2D-SWE have not been systematically investigated.

MATERIALS AND METHODS

We prospectively recruited participants with paired LSM by VCTE and the novel 2D-SWE technique ElastQ (Philips) in three European tertiary centers. The following parameters were recorded: sex, age, body mass index (BMI), etiology, laboratory markers of liver damage and function, as well as cholestasis, LSM by VCTE and controlled attenuation parameter (CAP), interquartile range (IQR)/median for VCTE-LSM and ElastQ-LSM, and the skin-to-liver capsule distance.

RESULTS

We included 840 participants: 447 (53.2%) males; median age 57.0 [IQR:19.0] years; median BMI 25.4 [6.0] kg/m2; median VCTE-LSM 7.25 [9.2] kPa; median ElastQ-LSM 6.7 [5.4] kPa. On uni- and multivariable modeling (adjusted for LSM), we found that the discrepancy increased with liver stiffness and markers of disease severity. Skin-to-liver capsule distance and BMI affected VCTE-LSM more compared to ElastQ-LSM and significantly increased the discordance between the two measurements.

CONCLUSION

The discrepancy of ElastQ-LSM to VCTE-LSM increases with liver stiffness and disease severity. BMI and skin-to-liver capsule distance increase the discrepancy between VCTE- and ElastQ-LSM but affect ElastQ-LSM less. The quality criterion IQR/median ≤ 30% indicates reliable ElastQ-LSM.

WFUMB Guideline/Guidance on Liver Multiparametric Ultrasound: Part 1. Update to 2018 Guidelines on Liver Ultrasound Elastography

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.

The Effect of Steatosis on Shear-Wave Velocity and Viscoelastic Properties Related to Liver Fibrosis Progression in Rat Models

OBJECTIVE

Hepatic fibrosis has recently been evaluated using ultrasonography or magnetic resonance elastography. Although the shear wave velocity (SWV) obtained using point shear wave elastography (pSWE) provides a valuable measure of fibrosis, underlying steatosis may affect its measurement.

METHODS

Using hepatic fibrosis samples, this study evaluated the effect of steatosis on the shear wave velocity of pSWE (Vs) and viscoelastic properties (assessed by dynamic mechanical analysis) of rat liver. Fifty rats with various grades of steatosis and fibrosis underwent open abdominal in vivo Vs measurements using a commercial ultrasound scanner. The mechanical properties of hepatic tissue were also characterized under ex vivo conditions using dynamic mechanical analysis and the Zener model of viscoelasticity.

RESULTS

Fibrosis and steatosis progression influenced Vs and elasticity. The SWV computed using the Zener model and Vs showed a substantial correlation (r > 0.8). Fibrosis progression increased SWV. Steatosis was also related to SWV. Steatosis progression obscured the SWV change associated with fibrosis progression.

CONCLUSION

We conclude that steatosis progression affects the evaluation of fibrosis progression. This finding could aid discrimination of non-alcoholic steatohepatitis from non-alcoholic fatty liver disease using SWV.

Imaging of Alcohol-Associated Liver Disease

Alcohol-associated liver disease (ALD) continues to be a global health concern, responsible for a significant number of deaths worldwide. Although most individuals who consume alcohol do not develop ALD, heavy drinkers and binge drinkers are at increased risk. Unfortunately, ALD is often undetected until it reaches advanced stages, frequently associated with portal hypertension and hepatocellular carcinoma (HCC). ALD is now the leading indication for liver transplant. The incidence of alcohol-associated hepatitis (AH) surged during the COVID-19 pandemic. Early diagnosis of ALD is therefore important in patient management and determination of prognosis, as abstinence can halt disease progression. The spectrum of ALD includes steatosis, steatohepatitis, and cirrhosis, with steatosis the most common manifestation. Diagnostic techniques including ultrasound, CT, and MRI provide useful information for identifying ALD and excluding other causes of liver dysfunction. Heterogeneous steatosis and transient perfusion changes on CT and MRI in the clinical setting of alcohol-use disorder are diagnostic of severe AH. Elastography techniques are useful for assessing fibrosis and monitoring treatment response. These various imaging modalities are also useful in HCC surveillance and diagnosis. This review discusses the imaging modalities currently used in the evaluation of ALD, highlighting their strengths, limitations, and clinical applications.

Diagnostic efficiency on ultrasound shear wave elastography in evaluation of steatosis severity for non-alcoholic fatty liver disease: a rat model

BACKGROUND

The pathological feature of steatosis affects the elasticity values measured by shear wave elastography (SWE) is still controversial in non-alcoholic fatty liver disease (NAFLD). The aim of this study is to demonstrate the influence of steatosis on liver stiffness measured by SWE on a rat model with NAFLD and analyze feasibility of SWE for grading steatosis in absence of fibrosis.

METHODS

Sixty-six rats were fed with methionine choline deficient diet or standard diet to produce various stages of steatosis; 48 rats were available for final analysis. Rats underwent abdominal ultrasound SWE examination and pathological assessment. Liver histopathology was analyzed to assess the degree of steatosis, inflammation, ballooning, and fibrosis according to the non-alcoholic fatty liver disease activity score. The diagnostic performance of SWE for differentiating steatosis stages was estimated according to the receiver operating characteristic (ROC) curve. Decision curve analysis (DCA) was conducted to determine clinical usefulness and the areas under DCA (AUDCAs) calculated.

RESULTS

In multivariate analysis, steatosis was an independent factor affecting the mean elastic modules (B = 1.558, P < 0.001), but not inflammation (B =  - 0.031, P = 0.920) and ballooning (B = 0.216, P = 0.458). After adjusting for inflammation and ballooning, the AUROC of the mean elasticity for identifying S ≥ S1 was 0.956 (95%CI: 0.872-0.998) and the AUDCA, 0.621. The AUROC for distinguishing S ≥ S2 and S = S3 was 0.987 (95%CI: 0.951-1.000) and 0.920 (95%CI: 0.816-0.986) and the AUDCA was 0.506 and 0.256, respectively.

CONCLUSIONS

Steatosis is associated with liver stiffness and SWE may have the feasibility to be introduced as an assistive technology in grading steatosis for patients with NAFLD in absence of fibrosis.

Application of attenuation coefficient in the assessment of hepatic involvement in children and adolescents with Wilson's disease

BACKGROUND

To investigate whether the attenuation coefficient (ATT) can be used as a noninvasive index to assess liver involvement in children and adolescents with Wilson's disease (WD).

METHODS

Children and adolescents diagnosed with WD were retrospectively collected from the First Affiliated Hospital of the Anhui University of Traditional Chinese Medicine between May 2022 and August 2022. The findings on ATT, Shear Wave Measurement (SWM), AST to platelet ratio index (APRI), and fibrosis 4 (FIB-4) score were obtained. The liver involvement of WD was classified into 3 groups based on serum levels of collagen type IV (CIV), hyaluronic acid (HA), laminin (LN) and precollagen type III N-terminal peptide (PIIINP): (1) Group1 (n = 25), no abnormalities in CIV, HA, LN and PIIINP; (2) Group2 (n = 19), elevation of 1 or 2 indexes in CIV, HA, LN, and PIIINP; Group3 (n = 18), elevation of 3 or 4 indicators in CIV, HA, LN, and PIIINP. The levels of ATT, SWM, APRI and FIB-4 were compared between the 3 groups; and correlation of ATT with SWM and triglyceride (TG) was performed using Spearman's correlation analysis. The Receiver operating characteristic (ROC) curve was used to analyze the diagnostic efficacy of ATT alone and its combination with SWM, APRI, and FIB-4 in children and adolescents with WD.

RESULTS

A total of 62 children and adolescents with WD were retrospectively retrieved. ATT levels were significantly different in intergroup comparisons (P < 0.001). The ROC curve showed that the area under the curve (AUC) for the diagnosis of hepatic steatosis using ATT was 0.714, 0.712 and 0.867 in Group 1 versus Group 2, Group 2 versus Group 3, and Group 1 versus Group 3, respectively; the sensitivity for the diagnosis of hepatic steatosis in Group 1 versus Group 2 was 89.47% with the cutoff value of ATT of 0.73 dB/cm/MHz. No significant correlation found between ATT and TG (ρ = 0.154, P = 0.231). Compared to ATT alone, the combination of ATT with APRI and FIB-4 or the combination of ATT with SWM, APRI, and FIB-4 showed a better diagnostic efficacy in Group 1 versus Group 2 (both P = 0.038).

CONCLUSION

ATT could be used as a non-invasive index for the evaluation of liver steatosis in children and adolescents with WD, with a good clinical applicative value. Furthermore, ATT in combination with APRI, FIB-4, and SWM might have better diagnostic efficacy than ATT alone.

Diagnostic Performance of Transient Elastography Versus Two-Dimensional Shear Wave Elastography for Liver Fibrosis in Chronic Viral Hepatitis: Direct Comparison and a Meta-Analysis

Objective

This systematic review and meta-analysis aimed to compare the diagnostic performance of transient elastography (TE) and two-dimensional shear wave elastography (2D-SWE) for staging liver fibrosis in patients with chronic viral hepatitis (CVH).

Methods

Pubmed, Embase, Web of Science, and Cochrane Library were searched (-01/08/2021) for studies comparing TE with 2D-SWE in patients with CVH. Other etiologies of chronic liver disease (CLD) and articles not published in SCI journals were excluded. The bivariate random-effects model was used to pool the performance of the TE and 2D-SWE.

Results

Eight articles with a total of 1301 CVH patients were included. The prevalence of significant fibrosis (fibrosis stage ≥ 2), advanced fibrosis (fibrosis stage ≥ 3), and cirrhosis was 50.8%, 44.8%, and 34.7%, respectively. 2D-SWE expressed higher overall accuracy than TE in detecting significant fibrosis (0.93 vs. 0.85, P = 0.04). No significant difference among the overall diagnostic accuracy of TE and 2D-SWE in staging advanced fibrosis and cirrhosis was found.

Conclusion

TE and 2D-SWE express good to excellent diagnostic accuracies to stage fibrosis in CVH patients. 2D-SWE compares favorably with TE especially for predicting significant fibrosis.

Liver Stiffness Measurements by 2D Shear-Wave Elastography: Effect of Steatosis on Fibrosis Evaluation

Background: Hepatic steatosis has been shown to not effect liver stiffness measurements (LSM) by MR elastography (MRE). However, the effect of steatosis on LSM by 2D shear-wave elastography (SWE) remains controversial. Objective: To evaluate the effect of hepatic steatosis on the diagnostic performance of LSM from 2D SWE (hereafter, LSM2D-SWE) for evaluation of liver fibrosis, using LSM from MRE (hereafter, LSMMRE) as the reference standard. Methods: This retrospective study included 888 patients (442 women, 446 men; median age, 67 years) with chronic liver disease who underwent LSM by both 2D SWE and MRE within a 3-month window. Steatosis was also assessed on the ultrasound examinations by ultrasound-guided attenuation parameter (UGAP) and on the MRI examinations by MRI-based proton-density fat fraction (MRI-PDFF). Fibrosis stages and steatosis grades were classified using previously established thresholds. The effect of steatosis on LSM2D-SWE was evaluated using Kruskal-Wallis tests with post hoc tests and ROC analysis. Results: LSM2D-SWE was significantly higher in patients with severe steatosis than no steatosis by MRI-PDFF among patients with F0 fibrosis [5.5 (interquartile range [IQR], 4.7-6.0) vs 4.7 (IQR, 4.2-5.5), p=.009)] and F1 fibrosis [6.3 (IQR, 6.0-7.2) vs 5.9 (IQR, 5.0-6.6), p=.009]. LSM2D-SWE was significantly higher in patients with severe steatosis than no steatosis by UGAP among patients with F1 fibrosis [6.6 (IQR, 5.9-7.3) vs 5.9 (IQR, 5.1-6.5), p=.008)]. Otherwise, LSM2D-SWE did not vary significantly across steatosis grades at a given fibrosis stage (all p>.05). Sensitivity and specificity for ≥F1 fibrosis were 63.8% and 91.5% in patients without, versus 60.4% and 80.9% in patients with, severe steatosis by MRI-PDFF, and were 62.4% and 91.5% in patients without, versus 72.1% and 78.3% in patients with, severe steatosis by UGAP. Conclusion: Severe hepatic steatosis may result in overestimation of LSM2D-SWE in patients with no or mild steatosis, thus reducing specificity for liver fibrosis detection. Clinical impact: UGAP performed at the time of 2D SWE may help identify patients in whom LSM2D-SWE should be assessed with caution. In patients with no or mild steatosis by 2D SWE and severe steatosis by UGAP, MRE may help provide a more reliable measure of liver fibrosis.

Reliability of performing ultrasound derived SWE and fat fraction in adult livers

PURPOSE

The aim of the study was to test the reproducibility of performing conventional point shear wave elastography (pSWE), auto-pSWE, and ultrasound derived fat fraction (UDFF) in adult livers.

METHODS

The Institutional Review Board approved the study and all participants provided written informed consent. Conventional pSWE (obtaining 10 measurements through 10 acquisitions), auto-pSWE (automatically obtaining 15 measurements by a single acquisition), and UDFF (one measurement obtained by one acquisition) of the liver were prospectively performed in 21 participants (10 men, 11 women, mean age 63y) by senior and junior operators in February-May 2021. Shear wave velocity (SWV, m/s) of the liver was measured by conventional pSWE and auto-pSWE. Intraclass correlation coefficient (ICC) and Bland-Altman limits of agreement were used to test intra-observer repeatability and inter-observer reproducibility in measuring pSWE, auto-pSWE, and UDFF.

RESULTS

ICC for testing intra-observer repeatability and inter-observer reproducibility in performing pSWE, auto-pSWE, and UDFF was >0.85 (95% confidence interval 0.85-0.99). The mean difference of 95% Bland-Altman limits of agreement was -0.02 (upper 0.09, lower -0.12) and the correlation of SWV measured between conventional pSWE and auto-pSWE methods was strong (r² = 0.87).

CONCLUSION

Our results suggest good repeatability and reproducibility in measuring UDFF and SWV in adult livers. The auto-pSWE has higher reliability, reproducibility and time efficacy in measuring SWV of adult livers when compared to conventional pSWE method.