Intra-Individual Comparison between 2-D Shear Wave Elastography (GE System) and Virtual Touch Tissue Quantification (Siemens System) in Grading Liver Fibrosis

Serum omentin-1 is correlated with the severity of liver disease in patients with chronic hepatitis C

BACKGROUND

Patients with chronic hepatitis C virus (HCV) infection have increased serum omentin-1. Omentin-1 is an anti-inflammatory adipokine, and higher levels may be a direct effect of HCV infection. Successful elimination of HCV by direct acting antivirals almost normalized circulating levels of various molecules with a role in inflammation.

AIM

To evaluate the effect of HCV infection on serum omentin-1, serum omentin-1 levels of HCV patients were measured before therapy and at 12 wk after therapy end. Associations of serum omentin-1 with parameters of inflammation and liver function were explored at both time points. Serum omentin-1 levels of patients with and without liver cirrhosis, which was defined by ultrasound or the fibrosis-4 (FIB-4) score, were compared.

METHODS

Serum omentin-1 levels were measured by enzyme-linked immunosorbent assay in 84 chronic HCV patients before therapy and at 12 wk after therapy end where sustained virological response 12 (SVR12) was achieved in all patients. Serum omentin-1 of 14 non-infected controls was measured in parallel.

RESULTS

In patients with chronic HCV, serum omentin-1 levels were not related to viral load or viral genotype. HCV patients with liver steatosis and HCV patients with diabetes had serum omentin-1 levels comparable to patients not suffering from these conditions. Serum omentin-1 levels at SVR12 were similar in comparison to pretreatment levels. In addition, serum levels did not differ between HCV-infected patients and non-infected controls. Serum omentin-1 levels did not correlate with leukocyte count or C-reactive protein. Positive correlations of serum omentin-1 with bilirubin and the model for end-stage liver disease score (MELD) were detected before therapy and at SVR12 in the whole cohort. Bilirubin and the MELD score also positively correlated with serum omentin-1 levels in the subgroup of patients with ultrasound diagnosed liver cirrhosis before therapy. At SVR12, serum omentin-1 levels of patients with liver cirrhosis negatively correlated with albumin. Before therapy start, patients with high FIB-4 scores had increased serum omentin-1 in comparison to patients with a low score. Serum omentin-1 levels of patients with liver cirrhosis defined by ultrasound were increased at baseline and at SVR12.

CONCLUSION

Present study showed that liver cirrhosis, but not HCV infection per se, is related to elevated serum omentin-1 levels.

Comparison Between Different Manufacturers' 2-D and Point Shear Wave Elastography Techniques in Staging Liver Fibrosis in Chronic Liver Disease Using Liver Biopsy as the Reference Standard: A Prospective Study

The purpose of this study was to assess the utility of 2-D shear wave elastography (SWE) in assessing liver fibrosis in patients with chronic liver disease by comparing its performance with that of point shear wave elastography (pSWE) using liver histological staging as the reference standard. In this ethics committee-approved, single-institution prospective study, pSWE and 2-D SWE velocity measurements were obtained in 121 adult patients (age: 18-70 y, median: 45 y) immediately before a liver biopsy for chronic liver disease. Shear wave velocity (SWV) and Ishak scores were compared using the Kruskal-Wallis test, Spearman's correlation and receiver operating characteristic (ROC) curve analysis. Youden's index was used to determine the optimal cutoff point. There was no technical failure using pSWE and 2-D SWE. The mean difference for SWV between pSWE and 2-D SWE was 0.0223 (limits of agreement: -1.1009, 1.1145). Values for both pSWE and 2-D SWE were significantly correlated with fibrosis stage (Spearman's ρ = 0.606, p < 0.0001; ρ = 0.722, p < 0.001 respectively). The area under the ROC curve differentiating F ≥3 was 0.855 (95% confidence interval: 0.778-0.932) for pSWE and 0.884 (95% CI: 0.817-0.951) for 2-D SWE. The AUC for differentiating F ≥5 was 0.890 (95% CI: 0.826-0.954) for pSWE and 0.926 (95% CI: 0.88-0.973) for 2-D SWE. This study indicates that 2-D SWE provides feasible and accurate assessment of liver fibrosis, comparable to that provided by pSWE from two different manufacturers' machines.

A Cross-Machine Comparison of Shear-Wave Speed Measurements Using 2D Shear-Wave Elastography in the Normal Female Breast

Quantitative measures of radiation-induced breast stiffness are required to support clinical studies of novel breast radiotherapy regimens and exploration of personalised therapy, however, variation between shear-wave elastography (SWE) machines may limit the usefulness of shear-wave speed (cs) for this purpose. Mean cs measured in four healthy volunteers’ breasts and a phantom using 2D-SWE machines Acuson S2000 (Siemens Medical Solutions) and Aixplorer (Supersonic Imagine) were compared. Shear-wave speed was measured in the skin region, subcutaneous adipose tissue and parenchyma. cs estimates were on average 2.3% greater when using the Aixplorer compared to S2000 in vitro. In vivo, cs estimates were on average 43.7%, 36.3% and 49.9% significantly greater (p << 0.01) when using the Aixplorer compared to S2000, for skin region, subcutaneous adipose tissue and parenchyma, respectively. In conclusion, despite relatively small differences between machines observed in vitro, large differences in absolute measures of shear wave speed measured were observed in vivo, which may prevent pooling of cross-machine data in clinical studies of the breast.

Liver stiffness assessed by shear-wave elastography declines in parallel with immunoregulatory proteins in patients with chronic HCV infection during DAA therapy

BACKGROUND

A rapid decline of liver stiffness (LS) was detected by non-invasive methods in patients with chronic hepatitis C (HCV) infection during treatment with direct-acting antivirals (DAA).

OBJECTIVE

To investigate the influence of inflammation on LS.

METHODS

We prospectively examined LS by sonographic shear-wave elastography in 217 patients during DAA therapy from treatment initiation (BL) to 12 weeks after end of therapy (SVR12). Demographic data, laboratory findings and serum levels of cytokines were determined.

RESULTS

Values of LS decreased from 1.86 m/s to 1.68 m/s (p = 0.01) which was most pronounced in patients who had F4 fibrosis at BL (3.27 m/s to 2.37 m/s; p <  0.001). Initially elevated values of aminotransferases, ferritin, IgG (p <  0.001 each) and international normalized ratio (p <  0.003) declined, thrombocyte count (p = 0.007) increased. Correlations of these laboratory parameters with BL levels of LS measurement (LSM) were most apparent in patients with F1-F3 fibrosis. Tumor necrosis factor (TNF)-α (p = 0.031), interleukin (IL)-10 (p = 0.005) and interferon y inducible protein (IP)-10 (p <  0.001) decreased in parallel with LSM under DAA therapy and corelated with BL values.

CONCLUSION

Decrease of systemic inflammatory parameters correlated with LSM under DAA therapy. We conclude that regression of LSM is attributable to the decline of inflammation rather than reflecting fibrosis.

Shear wave-based sound touch elastography in liver fibrosis assessment for patients with autoimmune liver diseases

Background

Shear wave-based ultrasonic elastography (USE) has been widely used for the assessment of liver fibrosis in patients with chronic liver diseases (CLD). However, diagnostic criteria and accuracy vary between different etiologies and specific elastography techniques. We aimed to evaluate the tissue stiffness measured by shear wave-based sound touch elastography (STE) in staging liver fibrosis in patients with autoimmune liver diseases (AILD).

Methods

One hundred and two AILD patients who had undergone STE liver stiffness measurements (LSMs) by using a Resona 7 ultrasound system were retrospectively studied. With the Scheuer liver fibrosis staging system as the reference, we investigated the diagnostic performance and cutoff values of STE measured liver stiffness in staging liver fibrosis through receiver operating characteristic (ROC) curve analysis. Moreover, comparisons of areas under the curve (AUCs) were made between LSMs and calculated biomarker scores, including the aspartate aminotransferase (AST)-to-platelet ratio index (APRI), and fibrosis-4 (FIB-4) index.

Results

Median LSMs increased with the advancing fibrosis stages with values of 6.89 kPa (1.51 m/s), 8.00 kPa (1.63 m/s), 9.60 kPa (1.79 m/s), 11.37 kPa (1.95 m/s) and 14.50 kPa (2.20 m/s), from stage 0 to stage 4 respectively. The cutoff values of STE for identifying significant fibrosis (≥ stage 2), severe fibrosis (≥ stage 3) and cirrhosis (stage 4) were 9.07 kPa (1.74 m/s), 9.97 kPa (1.82 m/s) and 10.48 kPa (1.87 m/s), respectively, with corresponding sensitivity of 79.1%, 93.3%, and 100%; specificity of 80.0%, 70.8% and 71.8%. The AUCs of LSMs in identifying fibrosis ≥ stage 2, ≥ stage 3 and stage 4 (0.82, 0.87, and 0.91, respectively) were significantly higher than that of APRI (0.67, 0.64, and 0.72, respectively) and FIB-4 (0.70, 0.68, and 0.75, respectively) (all P<0.05).

Conclusions

LSM obtained by STE exhibited its good capability to evaluate liver fibrosis stages in patients with AILD. As a noninvasive modality for liver fibrosis staging, STE is superior to APRI and FIB-4 biomarker scores.

Interobserver and Intraobserver Reliability of Hepatic Shear Wave Elastography and the Influence of Fasted Versus Nonfasted States in Healthy Volunteers

OBJECTIVES

The primary objective of this study was to assess the effect of fasting versus ingestion of food and water on hepatic measurements by shear wave elastography (SWE) in healthy participants. The secondary objective was to assess inter- and intra-reader reliability of hepatic elastography in healthy participants.

METHODS

Twenty healthy participants were enrolled in this prospective study and underwent quantitative SWE under fasting conditions and after the ingestion of water and food and water. Two blinded sonographers each independently performed a total of 6 sessions of hepatic SWE in each participant. Sessions 1 to 3 were performed on day 0 and sessions 4 to 6 on day 7. Statistical tests used included the Wilcoxon signed ranks test, the intraclass correlation coefficient, and Bland-Altman plots.

RESULTS

There were no significant differences in hepatic SWE measurements after the ingestion of water versus the fasting state. Statistical significance was assessed as P < 0.05. The postprandial status had a statistically significant effect on hepatic SWE measurements at 1 hour (P = .04) but not at 3 hours (P = .08). By the intraclass correlation coefficient, there was poor-to-moderate inter-reader agreement and minimal-to-moderate intra-reader agreement. The median inter-reader difference in SWE measurements ranged from 0.66 to 0.96 kPa. The median intra-reader difference ranged from 0.43 to 0.55 kPa.

CONCLUSIONS

Our study shows that the ingestion of water has no effect on hepatic SWE measurements in healthy participants. The postprandial state had a significant effect on SWE measurements at 1 hour after ingestion but not at 3 hours. The inter-reader and intra-reader agreements were variable and moderate at best.

Shear wave elastography-based ultrasomics: differentiating malignant from benign focal liver lesions

PURPOSE

Ultrasomics is a radiomics technique that extracts high-throughput quantitative data from ultrasound imaging. The aim of this study was to differentiate malignant from benign focal liver lesions (FLLs) using two-dimensional shear wave elastography (2D-SWE)-based ultrasomics.

METHODS

A total of 175 FLLs in 169 patients were prospectively analyzed. The study population was divided into a training cohort (n = 122) and a validation cohort (n = 53). The maxima, minima, mean, and standard deviation of 2D-SWE measurements were expressed in kilopascals (E_max, E_min, E_mean, and E_SD). The ultrasonics technique was used to extract the features from the 2D-SWE images. Support vector machine was used to establish two prediction models: the ultrasomics score (ultrasomics features only) and the combined score (SWE measurements and ultrasomics features). The diagnostic performance of the models in differentiating FLLs was analyzed.

RESULTS

A total of 1044 features were extracted and 15 features were selected. The AUC for the combined score, ultrasomics score, E_max, E_mean, E_min and E_SD were 0.94, 0.91, 0.92, 0.89, 0.67, and 0.89, respectively. The combined score had the best diagnostic performance. The sensitivity, specificity, PPV, NPV, +LR, LR of the combined score were 92.59%, 87.50%, 94.59%, 82.50%, 7.35%, and 0.09%, respectively. The decision curve analysis results showed that when the threshold probability was > 29%, the combined score showed improved benefits for patients compared to using the ultrasomics score and 2D-SWE measurements.

CONCLUSION

The results of this study demonstrated that the combined score had good diagnostic accuracy in differentiating malignant from benign FLLs.

Noninvasive assessment of liver fibrosis in chronic hepatitis B carriers with sound touch elastography: study of surgical pathology specimens

PURPOSE

To evaluate the diagnostic performance of sound touch elastography (STE) for staging liver fibrosis in chronic hepatitis B (CHB) patients using pathological stage of surgical specimens as the reference standard.

METHOD

239 CHB patients were included. Liver stiffness measurements (LSMs) on STE and Supersonic shear imaging (SSI), gamma glutamyl transferase-to-platelet ratio (GPR), aspartate aminotransferase-to-platelet ratio index (APRI) and four-factor Fibrosis-4 (FIB-4) index were obtained. Areas under the receiver operating characteristic (ROC) curves (AUCs) for the diagnosis of fibrosis stage were calculated and compared.

RESULTS

The LSMs obtained by STE and SSI significantly correlated with the fibrosis stages (r = 0.757; r = 0.758, respectively, both p < 0.001). No significant differences in AUCs were observed between STE and SSI in identifying fibrosis ≥stage 1 (0.92 vs. 0.94), ≥stage 2 (0.89 vs. 0.91), ≥stage 3 (0.90 vs. 0.91) or stage 4 (0.92 vs. 0.91). Both STE and SSI had significantly higher AUCs in identifying each fibrosis stage than the GPR (0.68, 0.77, 0.76 and 0.79), APRI (0.53, 0.66, 0.74 and 0.69) and FIB-4 (0.61, 0.77, 0.79 and 0.74).

CONCLUSIONS

STE is an efficient tool for assessing liver fibrosis in CHB patients, with performance comparable to that of SSI and superior to that of biomarkers.

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.

Quantitative ultrasound approaches for diagnosis and monitoring hepatic steatosis in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease is a major global health concern with increasing prevalence, associated with obesity and metabolic syndrome. Recently, quantitative ultrasound-based imaging techniques have dramatically improved the ability of ultrasound to detect and quantify hepatic steatosis. These newer ultrasound techniques possess many inherent advantages similar to conventional ultrasound such as universal availability, real-time capability, and relatively low cost along with quantitative rather than a qualitative assessment of liver fat. In addition, quantitative ultrasound-based imaging techniques are less operator dependent than traditional ultrasound. Here we review several different emerging quantitative ultrasound-based approaches used for detection and quantification of hepatic steatosis in patients at risk for nonalcoholic fatty liver disease. We also briefly summarize other clinically available imaging modalities for evaluating hepatic steatosis such as MRI, CT, and serum analysis.

Point Shear Wave Elastography Using Machine Learning to Differentiate Renal Cell Carcinoma and Angiomyolipoma

The question of whether ultrasound point shear wave elastography can differentiate renal cell carcinoma (RCC) from angiomyolipoma (AML) is controversial. This study prospectively enrolled 51 patients with 52 renal tumors (42 RCCs, 10 AMLs). We obtained 10 measurements of shear wave velocity (SWV) in the renal tumor, cortex and medulla. Median SWV was first used to classify RCC versus AML. Next, the prediction accuracy of 4 machine learning algorithms-logistic regression, naïve Bayes, quadratic discriminant analysis and support vector machines (SVMs)-was evaluated, using statistical inputs from the tumor, cortex and combined statistical inputs from tumor, cortex and medulla. After leave-one-out cross validation, models were evaluated using the area under the receiver operating characteristic (ROC) curve (AUC). Tumor median SWV performed poorly (AUC = 0.62; p = 0.23). Except logistic regression, all machine learning algorithms reached statistical significance using combined statistical inputs (AUC = 0.78-0.98; p < 7.1 × 10-3). SVMs demonstrated 94% accuracy (AUC = 0.98; p = 3.13 × 10-6) and clearly outperformed median SWV in differentiating RCC from AML (p = 2.8 × 10-4).

Assessment of liver fibrosis using 2-dimensional shear wave elastography: a prospective study of intra- and inter-observer repeatability and comparison with point shear wave elastography

PURPOSE

The purpose of this study was to prospectively investigate the intra- and interobserver repeatability of a new 2-dimensional (2D) shear wave elastography (SWE) technique (S-Shearwave Imaging) for assessing liver fibrosis in chronic liver disease patients, and to compare liver stiffness measurements (LSMs) made using 2D-SWE with those made using point SWE (pSWE).

METHODS

This prospective study received institutional review board approval and informed consent was obtained from all patients. Fifty-three chronic liver disease patients were randomly allocated to group 1 (for intra-observer repeatability [n=33]) or group 2 (for inter-observer repeatability [n=20]). In group 1, two 2D-SWE sessions and one pSWE sessions were performed by one radiologist. In group 2, one 2D-SWE session and one pSWE session were performed by the aforementioned radiologist, and a second 2D-SWE session was performed by another radiologist. The intraclass correlation coefficient (ICC) was used to assess intra- and interobserver reliability. LSMs obtained using 2D-SWE and pSWE were compared and correlated using the paired t test and Pearson correlation coefficient, respectively.

RESULTS

LSMs made using 2D-SWE demonstrated excellent intra- and inter-observer repeatability (ICC, 0.997 [95% confidence interval, 0.994 to 0.999]) and 0.995 [0.988 to 0.998], respectively). LSMs made using 2D-SWE were significantly different from those made using pSWE (2.1±0.6 m/sec vs. 1.9±0.6 m/sec, P<0.001), although a significant correlation existed between the 2D-SWE and pSWE LSMs (rho=0.836, P<0.001).

CONCLUSION

S-Shearwave Imaging demonstrated excellent intra- and inter-observer repeatability, and a strong correlation with pSWE measurements of liver stiffness. However, because of the significant difference between LSMs obtained using 2D-SWE and pSWE, these methods should not be used interchangeably.

Reproducibility of liver stiffness measurements made with two different 2-dimensional shear wave elastography systems using the comb-push technique

Purpose

The purpose of this study was to retrospectively compare the technical success and reliability of the measurements made using two 2-dimensional (2D) shear wave elastography (SWE) systems using the comb-push technique from the same manufacturer and to assess the intersystem reproducibility of the resultant liver stiffness (LS) measurements.

Methods

Ninety-four patients with suspected chronic liver diseases were included in this retrospective study. LS measurements were obtained using two 2D-SWE systems (LOGIQ E9 and LOGIQ S8) from the same manufacturer, with transient elastography (TE) serving as the reference standard, on the same day. The technical success rates and reliability of the measurements of the two 2D-SWE systems were compared. LS values measured using the two 2D-SWE systems and TE were correlated using Spearman correlation coefficients and 95% Bland-Altman limits of agreement. Thereafter, Bland-Altman limits of agreement and intraclass correlation coefficients (ICCs) were used to analyze the intersystem reproducibility of LS measurements.

Results

The two 2D-SWE systems showed similar technical success rates (98.9% for both) and reliability of LS measurements (92.3% for the LOGIQ E9, 91.2% for the LOGIQ S8; P=0.185). Despite the excellent correlation (ICC=0.92), the mean LS measurements obtained by the two 2D-SWE systems were significantly different (LOGIQ E9, 6.57±2.33 kPa; LOGIQ S8, 6.90±6.64 kPa; P=0.018).

Conclusion

Significant intersystem variability was observed in the LS measurements made using the two 2D-SWE systems. Therefore, even 2D-SWE systems from the same manufacturer should not be used interchangeably in longitudinal follow-up.