Shear-Wave Dispersion Slope from US Shear-Wave Elastography: Detection of Allograft Damage after Liver Transplantation

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.

Usefulness of Picture Archiving and Communication System-Based Quantitative Ultrasound Measurements in Evaluation of Allograft Dysfunction in Patients With Liver Transplantation

OBJECTIVE

The aim of this study was to assess the usefulness of picture archiving and communication system (PACS)-based quantitative grayscale ultrasonography (US) measurements in detecting allograft dysfunction in posttransplant patients.

METHODS

In this retrospective study, 116 patients with liver transplantation who underwent biopsy for allograft evaluation were recruited from the database. All participants had US images prior to procedure. Normal, acute cellular rejection (ACR), recurrent hepatitis (Hep), or combined (ACR/Hep) groups were generated based on pathology results. Region of interests were drawn for liver and rectus abdominus muscle to perform quantitative US analysis. The liver/muscle mean ratio (L/M) and heterogeneity index (HI; liver standard deviation/liver mean) were obtained. The ratios of groups were compared, and receiver-operating-characteristic analysis was performed.

RESULTS

There was a significant difference between normal (n = 16) and each of other groups (ACR, 39; Hep, 36; combined, 25) for L/M and HI (P < 0.05). No significant difference was detected between ACR, Hep, and combined groups. The areas under the curve for L/M and HI were 0.755 (moderate) and 0.817 (good), respectively. To differentiate abnormal (ACR, Hep, and combined) from normal allografts sensitivity, specificity, PPV, and NPV were 50.0%, 87.5%, 96.2%, and 21.9% for cut point of L/M ≥1 and 84.0%, 68.8%, 94.4%, and 40.7% for cut point of HI ≥0.2 with odds ratios of 7.52 (for L/M ≥1) and 13.10 (for HI ≥0.2), respectively (P < 0.01).

CONCLUSIONS

L/M has moderate and HI has good discrimination of normal from abnormal allograft in liver transplant patients. PACS-based quantitative US measurements is an objective, easy to use, noninvasive auxiliary tool to discriminate hepatic allograft dysfunction.

Prediction of acute rejection in renal allografts using shear-wave dispersion slope

OBJECTIVES

To evaluate the role of shear-wave dispersion slope for predicting renal allograft dysfunction.

METHODS

We retrospectively reviewed 128 kidney transplant recipients (median age, 55 years [interquartile range, 43-62 years]; male, 68) who underwent biopsy for allograft evaluation from November 2022 to February 2023. Cortex and renal sinus fat stiffness and shear-wave dispersion slope were obtained at shear-wave elastography (SWE). Cortex-to-sinus stiffness ratio (SR) and dispersion slope ratio (DSR)-related clinical and pathologic factors were evaluated using multivariable linear regression analysis. We conducted univariate and multivariate analyses for multiparametric ultrasound (US) parameters for identifying acute rejection and calculated the area under the receiver operating curve (AUC) values.

RESULTS

Of 128 patients, 31 (24.2%) demonstrated acute rejection. The SR value did not differ between patient groups (1.21 vs. 1.20, p = 0.47). Patients with acute rejection demonstrated a higher DSR than those without rejection (1.4 vs. 1.21, p < 0.01). Interstitial fibrosis and tubular atrophy grade (IFTA; coefficient, 0.11/grade; p = 0.04) and renal transplant and biopsy interval (coefficient, 0.00007/day; p = 0.03) were SR determinant factors, whereas only IFTA grade (coefficient, 0.10/grade; p = 0.01) for DSR. Multivariate analysis revealed mean resistive index (odds ratio [OR] 1.08, 95% confidence interval [CI] 1.02-1.14, p = 0.01) and DSR value (OR 16.0, 95% CI 3.0-85.8, p = 0.001) as independent factors for predicting acute rejection. An AUC of 0.74 for detecting acute rejection was achieved by combining the resistive index and DSR value.

CONCLUSION

Shear-wave dispersion slope obtained at SWE may help identify renal allograft dysfunction.

CLINICAL RELEVANCE STATEMENT

Acute rejection in renal allografts is a major cause of allograft failure, but noninvasive diagnosis is a challenge. Shear-wave dispersion slope can identify acute rejection non-invasively.

KEY POINTS

• The interstitial fibrosis and tubular atrophy grade was a determinant factor for stiffness ratio and shear-wave dispersion slope ratio between cortex and renal sinus fat. • Shear-wave dispersion slope ratio between cortex and renal sinus fat could identify acute rejection in renal allografts. • A shear-wave dispersion slope has a potential to reduce unnecessary renal biopsy for evaluating renal allografts.

Shear wave elastography and dispersion imaging for hepatic veno-occlusive disease prediction after pediatric hematopoietic stem cell transplantation: a feasibility study

BACKGROUND

Non-invasive imaging modalities are warranted for diagnosing and monitoring veno-occlusive disease because early diagnosis and treatment improve the prognosis.

OBJECTIVE

To evaluate the usefulness of liver shear wave elastography (SWE) and shear wave dispersion (SWD) imaging in diagnosing and monitoring veno-occlusive disease in pediatric patients.

MATERIALS AND METHODS

We conducted a prospective cohort study at a single tertiary hospital from March 2021 to April 2022. The study protocol included four ultrasound (US) sessions: a baseline US and three follow-up US after hematopoietic stem cell transplantation. Clinical criteria, including the European Society for Blood and Marrow Transplantation criteria, were used to diagnose veno-occlusive disease. We compared clinical factors and US parameters between the veno-occlusive disease and non-veno-occlusive disease groups. The diagnostic performance of US parameters for veno-occlusive disease was assessed by plotting receiver operating characteristic (ROC) curves. We describe temporal changes in US parameters before and after veno-occlusive disease diagnosis.

RESULTS

Among the 38 participants (mean age 10.7 years), eight developed veno-occlusive disease occurring 17.0 ± 5.2 days after hematopoietic stem cell transplantation. Liver stiffness, as measured by SWE (15.0 ± 6.2 kPa vs. 5.8 ± 1.8 kPa; P<0.001), and viscosity, as assessed with SWD (17.7 ± 3.1 m/s/kHz vs. 14.3 ± 2.8 m/s/kHz; P=0.015), were significantly higher in the veno-occlusive disease group compared to the non-veno-occlusive disease group at the time of diagnosis. Liver stiffness demonstrated the highest area under the ROC (AUROC) curves at 0.960, with an optimal predictive value of >6.5 kPa, resulting in sensitivity and specificity of 100% and 83.3%, respectively. Viscosity demonstrated an AUROC of 0.783, with an optimal cutoff value of 13.9 m/s/kHz for predicting veno-occlusive disease, with a sensitivity of 100% and specificity of 53.3%, respectively. Liver stiffness increased with disease severity and decreased during post-treatment follow-up.

CONCLUSION

SWE may be a promising technique for early diagnosis and severity prediction of veno-occlusive disease. Furthermore, liver viscosity assessed by SWD may serve as an additional marker of veno-occlusive disease.

Ultrasound Viscosity Imaging in Breast Lesions: A Multicenter Prospective Study

RATIONALE AND OBJECTIVES

To explore and validate the clinical value of ultrasound (US) viscosity imaging in differentiating breast lesions by combining with BI-RADS, and then comparing the diagnostic performances with BI-RADS alone.

MATERIALS AND METHODS

This multicenter, prospective study enrolled participants with breast lesions from June 2021 to November 2022. A development cohort (DC) and validation cohort (VC) were established. Using histological results as reference standard, the viscosity-related parameter with the highest area under the receiver operating curve (AUC) was selected as the optimal one. Then the original BI-RADS would upgrade or not based on the value of this parameter. Finally, the results were validated in the VC and total cohorts. In the DC, VC and total cohorts, all breast lesions were divided into the large lesion, small lesion and overall groups respectively.

RESULTS

A total of 639 participants (mean age, 46 years ± 14) with 639 breast lesions (372 benign and 267 malignant lesions) were finally enrolled in this study including 392 participants in the DC and 247 in the VC. In the DC, the optimal viscosity-related parameter in differentiating breast lesions was calculated to be A'-S2-Vmax, with the AUC of 0.88 (95% CI: 0.84, 0.91). Using > 9.97 Pa.s as the cutoff value, the BI-RADS was then modified. The AUC of modified BI-RADS significantly increased from 0.85 (95% CI: 0.81, 0.88) to 0.91 (95% CI: 0.87, 0.93), 0.85 (95% CI: 0.80, 0.89) to 0.90 (95% CI: 0.85, 0.93) and 0.85 (95% CI: 0.82, 0.87) to 0.90 (95% CI: 0.88, 0.92) in the DC, VC and total cohorts respectively (P < .05 for all).

CONCLUSION

The quantitative viscous parameters evaluated by US viscosity imaging contribute to breast cancer diagnosis when combined with BI-RADS.

Evaluation of Robustness of S-Transform Based Phase Velocity Estimation in Viscoelastic Phantoms and Renal Transplants

Ultrasound shear wave elastography (SWE) methods are being used to differentiate healthy versus diseased tissue on the basis of their viscoelastic mechanical properties. Tissue viscoelasticity is often studied by analyzing shear wave phase velocity dispersion curves, which is the variation of phase velocity with frequency or wavelength. Recently, a unique approach using a generalized Stockwell transformation (GST-SFK) was proposed for the calculation of dispersion curves in viscoelastic media over expanded frequency band. In this work, the method's robustness was evaluated on data from five custom-made viscoelastic tissue-mimicking phantoms and sixty in vivo renal transplants. For each phantom, 15 shear wave motion data acquisitions were taken, while 10-13 acquisitions were acquired for renal transplants measured in the renal cortex. For each data-set mean and standard deviation (SD) of estimated phase velocity dispersion curves were studied. In addition, the viscoelastic parameters of the Zener model were examined, which were preceded by a convergence analysis. For viscoelastic phantoms scanned with a research ultrasound scanner, and for the in vivo renal transplants scanned with a clinical scanner, the decisive advantage of the GST-SFK method over the standard two-dimensional Fourier transform (2D-FT) method was shown. The GST-SFK method provided dispersion curve estimates with lower SD over a wider frequency band in comparison to the 2D-FT method. These advantages are relevant to the analysis of the mechanical properties of tissues in clinical practice to discriminate healthy from diseased tissue.

Kidney cortex shear wave motion simulations based on segmented biopsy histology

BACKGROUND AND OBJECTIVE

Biopsy stands as the gold standard for kidney transplant assessment, yet its invasive nature restricts frequent use. Shear wave elastography (SWE) is emerging as a promising alternative for kidney transplant monitoring. A parametric study involving 12 biopsy data sets categorized by standard biopsy scores (3 with normal histology, 3 with interstitial inflammation (i), 3 with interstitial fibrosis (ci), and 3 with tubular atrophy (ct)), was conducted to evaluate the interdependence between microstructural variations triggered by chronic allograft rejection and corresponding alterations in SWE measurements.

METHODS

Heterogeneous shear wave motion simulations from segmented kidney cortex sections were performed employing the staggered-grid finite difference (SGFD) method. The SGFD method allows the mechanical properties to be defined on a pixel-basis for shear wave motion simulation. Segmentation techniques enabled the isolation of four histological constituents: glomeruli, tubules, interstitium, and fluid. Baseline ex vivo Kelvin-Voigt mechanical properties for each constituent were drawn from established literature. The parametric evaluation was then performed by altering the baseline values individually. Shear wave velocity dispersion curves were measured with the generalized Stockwell transform in conjunction with slant frequency-wavenumber analysis (GST-SFK) algorithm. By fitting the curve within the 100-400 Hz range to the Kelvin-Voigt model, the rheological parameters, shear elasticity (µ1) and viscosity (µ2), were estimated. A time-to-peak algorithm was used to estimate the group velocity. The resultant in silico models emulated the heterogeneity of kidney cortex within the shear wave speed (SWS) reconstructions.

RESULTS

The presence of inflammation showed considerable spatial composition disparities compared to normal cases, featuring a 23 % increase in interstitial area and a 19 % increase in glomerular area. Concomitantly, there was a reduction of 12 % and 47 % in tubular and fluid areas, respectively. Consequently, mechanical changes induced by inflammation predominate in terms of rheological differentiation, evidenced by increased elasticity and viscosity. Mild tubular atrophy showed significant elevation in group velocity and µ1. Conversely, mild and moderate fibrosis exhibited negligible alterations across all parameters, compatible with relatively limited morphological impact.

CONCLUSIONS

This proposed model holds promise in enabling patient-specific simulations of the kidney cortex, thus facilitating exploration into how pathologies altering cortical morphology correlates to modifications in SWE-derived rheological measurements. We demonstrated that inflammation caused substantial changes in measured mechanical properties.

Diagnostic Performance of Quantitative Ultrasound Parameters in Non-alcoholic Fatty Liver Disease

RATIONALE AND OBJECTIVES

Marked liver steatosis, steatohepatitis, and significant fibrosis are risk factors for unfavorable outcomes in non-alcoholic fatty liver disease (NAFLD). In this study, the diagnostic performance of attenuation coefficient (AC), liver stiffness (LS), and dispersion slope (DS) was evaluated separately and combined in the diagnosis of liver steatosis and fibrosis in NAFLD suspects using biopsy or magnetic resonance imaging (MRI) as a reference standard.

MATERIALS AND METHODS

Seventy-four NAFLD suspects were prospectively imaged with an Aplio i800 ultrasound scanner (Canon Medical Systems, Tustin, CA). AC, LS, and DS measurements were obtained from the right liver lobe.

RESULTS

Thirty-four patients underwent liver biopsy, and 40 had MRI. There were 32 patients (43%) with liver steatosis and fibrosis (S + F), 22 (30%) with steatosis (S), 5 (7%) with fibrosis (F), and 15 (20%) with normal liver (N). Mean ACs were significantly higher in steatotic livers (n = 54) than in non-steatotic livers (n = 20) (P < 0.0001). LS and DS were significantly higher in patients with liver fibrosis (n = 37) compared to non-fibrotic livers (n = 37) (P = 0.0004 and P = 0.0002, respectively). In detecting (S + F), the area under the receiver operating characteristic curve (AUROCC) was 0.87 for combined ultrasound parameters of LS and AC (negative predictive value [NPV]: 75%, positive predictive value [PPV]: 77%, P < 0.0001). In detecting patients with liver steatosis and fibrosis stage ≥2, LS had an AUROCC of 0.93 (NPV: 87%, PPV: 82%, P < 0.0001). In the biopsy group, 32% (11/34) were diagnosed with non-alcoholic steatohepatitis (NASH). DS values showed a significant difference among patients with (n = 23) or without (n = 11) hepatocellular ballooning (P = 0.02). AUROCC was 0.87 for combined ultrasound parameters of AC, LS, and DS with body mass index (BMI) in detecting NASH (NPV: 80%, PPV: 87%, P = 0.0006).

CONCLUSION

AC and LS showed high diagnostic value in detecting liver steatosis and fibrosis, respectively. The combined AC and LS values further improved the diagnostic accuracy in detecting NAFLD and high-risk NAFLD patients.

A Comprehensive Review of Liver Allograft Fibrosis and Steatosis: From Cause to Diagnosis

Despite advances in posttransplant care, long-term outcomes for liver transplant recipients remain unchanged. Approximately 25% of recipients will advance to graft cirrhosis and require retransplantation. Graft fibrosis progresses in the context of de novo or recurrent disease. Recurrent hepatitis C virus infection was previously the most important cause of graft failure but is now curable in the majority of patients. However, with an increasing prevalence of obesity and diabetes and nonalcoholic fatty liver disease as the most rapidly increasing indication for liver transplantation, metabolic dysfunction-associated liver injury is anticipated to become an important cause of graft fibrosis alongside alloimmune hepatitis and alcoholic liver disease. To better understand the landscape of the graft fibrosis literature, we summarize the associated epidemiology, cause, potential mechanisms, diagnosis, and complications. We additionally highlight the need for better noninvasive methods to ameliorate the management of graft fibrosis. Some examples include leveraging the microbiome, genetic, and machine learning methods to address these limitations. Overall, graft fibrosis is routinely seen by transplant clinicians, but it requires a better understanding of its underlying biology and contributors that can help inform diagnostic and therapeutic practices.

Shear wave elastography and shear wave dispersion correlated to biopsy at the scheduled follow-up of pediatric liver grafts

BACKGROUND

It is unknown how shear wave dispersion (SWD) is displayed in pediatric liver transplant recipients and not fully elucidated how ultrasound shear wave elastography (2D-SWE) display within this cohort, which is important to determine to improve noninvasive surveillance of these patients. The study aimed to compare SWE and SWD values with histopathology in pediatric liver recipients.

METHODS

Forty-eight pediatric liver recipients were examined with SWE in conjunction with an elective liver biopsy (clinically without complication). Additionally, SWD values were measured in 21 children. SWE and SWD values were compared to histologically determined fibrosis graded as none-to-mild (F0-1) and moderate-to-severe (F2-4), and inflammation graded as low (grade 0-1) and high (grade 2-4).

RESULTS

Two children were excluded due to SWE IQR/median > 30% kPa. The mean age across 46 included patients was 10.9 years (range 1.4-18). The number of patients and median (range) SWE value (kPa) for each stage of fibrosis were: F0-1 [n = 23; 5.8 (3.2-16.1)], F2 [n = 22; 6.0 (4.5-25.9)], F3 [n = 1; 33.3], and F4 [n = 0]. Significantly higher SWE values and greater variability were registered in F2-4 vs. F0-1 (p = .05). Grade of fibrosis correlated weakly to SWE values (r = .3; p = .05), but not to SWD values (r = .2; p = .27). In patients with low-grade inflammation, median SWD was 13.7 m/s KHz (10.7-17.6). Only one patient had high-grade inflammation.

CONCLUSIONS

Uncomplicated transplanted liver grafts in a small pediatric cohort revealed slightly increased SWE and SWD values compared to previously reported values in healthy children. This likely reflect both the fibrotic and inflammatory elements in the grafts; however, other confounders impacting the liver's viscoelastic properties are also probable factors.

The value of shear wave elasticity and shear wave dispersion imaging to evaluate the viscoelasticity of renal parenchyma in children with glomerular diseases

BACKGROUND

To study the value of shear wave elasticity and shear wave dispersion imaging to evaluate the viscoelasticity of renal parenchyma in children with glomerular diseases.

METHODS

Forty-three children with glomerular diseases were prospectively evaluated by shear wave elasticity (SWE) and shear wave dispersion imaging (SWD); 43 healthy volunteers served as the control group. The shear wave velocities (SWV) and the dispersion slopes were measured at the upper, middle, and lower poles of both kidneys. The analysis of mean SWV and mean dispersion slope in control and patient groups was used to further evaluate the value of SWE and SWD in the viscoelasticity of renal parenchyma in children with glomerular disease.

RESULTS

The mean SWV in children with glomerular disease was higher than that in the healthy control group (1.61 ± 0.09 m/s vs. 1.43 ± 0.07 m/s, p < 0.001). Compared with healthy group, the mean dispersion slope in children with glomerular disease was significantly increased (13.5 ± 1.39 (m/s)/kHz vs. 12.4 ± 1.40 (m/s)/kHz, p < 0.001). Correlation analysis showed absence of correlation between the SWV and dispersion slope of occult blood, serum creatinine, 24-h urine protein, blood albumin, BMI and ROI box depth of children with glomerular disease.

CONCLUSIONS

The present study shows that it is feasible to use SWE and SWD to evaluate the difference of viscoelasticity of the renal parenchyma between healthy children and those with glomerular disease.

Clinical applications of shear wave dispersion imaging for breast lesions: a pictorial essay

Shear wave dispersion (SWD) imaging is a newly developed ultrasound technology designed to evaluate the dispersion slope of shear waves, which is related to tissue viscosity. This advanced imaging technique holds potential for distinguishing malignant lesions from benign lesions and normal breast tissue. The SWD slope, as determined by shear wave elastography (SWE), could offer crucial insights into the characterization of breast lesions. This article presents SWE and SWD images of both malignant and benign breast lesions, in addition to normal breast tissue.

Variability of Transrectal Shear Wave Elastography in a Phantom Model

Purpose

This study aimed to assess the variability of transrectal shear wave elastography (SWE) using a designed phantom.

Materials and Methods

In a phantom, the SWE values were examined by two radiologists using agarose and emulsion silicone of different sizes (1, 2, and 3 cm) and shapes (round, cubic) at three depths (1, 2, and 3 cm), two region of interest (ROI) and locations (central, peripheral) using two ultrasound machines (A, B from different vendors). Variability was evaluated using the coefficient of variation (CV).

Results

The CVs decreased with increasing phantom size. Significant changes in SWE values included; agarose phantom at 3 cm depth (p < 0.001; machine A), 1 cm depth (p = 0.01; machine B), emulsion silicone at 2 cm depth (p = 0.047, p = 0.020; both machines). The CVs increased with increasing depth. Significant changes in SWE values included; 1 cm agarose (p = 0.037, p = 0.021; both machines) and 2 cm agarose phantom (p = 0.047; machine A). Significant differences in SWE values were observed between the shapes for emulsion silicone phantom (p = 0.032; machines A) and between ROI locations on machine B (p ≤ 0.001). The SWE values differed significantly between the two machines (p < 0.05). The intra-/inter-operator agreements were excellent (intraclass correlation coefficient > 0.9).

Conclusion

The phantom size, depth, and different machines affected the variability of transrectal SWE.

Novel multi-parametric diagnosis of non-alcoholic fatty liver disease using ultrasonography, body mass index, and Fib-4 index

BACKGROUND

Shear wave speed (SWS), shear wave dispersion (SWD), and attenuation imaging (ATI) are new diagnostic parameters for non-alcoholic fatty liver disease. To differentiate between non-alcoholic steatohepatitis (NASH) and non-alcoholic fatty liver (NAFL), we developed a clinical index we refer to as the “NASH pentagon” consisting of the 3 abovementioned parameters, body mass index (BMI), and Fib-4 index.

AIM

To investigate whether the area of the NASH pentagon we propose is useful in discriminating between NASH and NAFL.

METHODS

This non-invasive, prospective, observational study included patients diagnosed with fatty liver by abdominal ultrasound between September 2021 and August 2022 in whom shear wave elastography, SWD, and ATI were measured. Histological diagnosis based on liver biopsy was performed in 31 patients. The large pentagon group (LP group) and the small pentagon group (SP group), using an area of 100 as the cutoff, were compared; the NASH diagnosis rate was also investigated. In patients with a histologically confirmed diagnosis, receiver-operating characteristic (ROC) curve analyses were performed.

RESULTS

One hundred-seven patients (61 men, 46 women; mean age 55.1 years; mean BMI 26.8 kg/m²) were assessed. The LP group was significantly older (mean age: 60.8 ± 15.2 years vs 46.4 ± 13.2 years; P < 0.0001). Twenty-five patients who underwent liver biopsies were diagnosed with NASH, and 6 were diagnosed with NAFL. On ROC curve analyses, the areas under the ROC curves for SWS, dispersion slope, ATI value, BMI, Fib-4 index, and the area of the NASH pentagon were 0.88000, 0.82000, 0.58730, 0.63000, 0.59333, and 0.93651, respectively; the largest was that for the area of the NASH pentagon.

CONCLUSION

The NASH pentagon area appears useful for discriminating between patients with NASH and those with NAFL.

Shear Wave Dispersion in Chronic Liver Disease: From Physical Principles to Clinical Usefulness

The development of new applications in ultrasound (US) imaging in recent years has strengthened the role of this imaging technique in the management of different pathologies, particularly in the setting of liver disease. Improved B-mode imaging (3D and 4D), contrast-enhanced US (CEUS) and especially US-based elastography techniques have created the concept of multiparametric ultrasound (MP-US), a term borrowed from radiological sectional imaging. Among the new elastography techniques, shear wave dispersion is a newly developed imaging technology which enables the assessment of the shear waves' dispersion slope. The analysis of the dispersion qualities of shear waves might be indirectly related to the tissue viscosity, thus providing biomechanical information concerning the pathologic state of the liver such as necroinflammation. Some of the most recent US devices have been embedded with software that evaluate the dispersion of shear waves/liver viscosity. In this review, the feasibility and the clinical applications of liver viscosity are reviewed based on the preliminary findings of both animal and human studies.

Role of Multiparametric Ultrasound in Evaluating Hepatic Acute Graft-versus-Host Disease: An Animal Study

OBJECTIVE

Hepatic acute graft-versus-host disease (aGVHD) is a serious complication of allogeneic hematopoietic stem cell transplantation (allo-HSCT) and is one of the leading causes of early non-recurrent death. The current diagnosis is based mainly based on clinical diagnosis, and there is a lack of non-invasive quantitative diagnosis methods. We propose a multiparametric ultrasound (MPUS) imaging method and explore its effectiveness in evaluating hepatic aGVHD.

METHODS

In this study, 48 female Wistar rats were used as receptors and 12 male Fischer 344 rats were used as donors for allo-HSCT to establish aGVHD models. After transplantation, 8 rats were randomly selected for ultrasonic examination weekly, including color Doppler ultrasound, contrast-enhanced ultrasound (CEUS) and shear wave dispersion (SWD) imaging. The values of nine ultrasonic parameters were obtained. Hepatic aGVHD was subsequently diagnosed by histopathological analysis. A classification model for predicting hepatic aGVHD was established using principal component analysis and support vector machines.

RESULTS

According to the pathological results, the transplanted rats were categorized into the hepatic aGVHD and non-GVHD (nGVHD) groups. All parameters obtained by MPUS differed statistically between the two groups. The first three contributing percentages of principal component analysis results were resistivity index, peak intensity and shear wave dispersion slope, respectively. The accuracy of classifying aGVHD and nGVHD using support vector machines reached 100%. The accuracy of the multiparameter classifier was significantly higher than that of the single parameter.

CONCLUSION

The MPUS imaging method has proven to be useful in detecting hepatic aGVHD.

Technical Acoustic Measurements Combined with Clinical Parameters for the Differential Diagnosis of Nonalcoholic Steatohepatitis

Background and aim: Diagnosing nonalcoholic steatohepatitis (NASH) is challenging. This study intended to explore the diagnostic value of multiple technical acoustic measurements in the diagnosis of NASH, and to establish a diagnostic model combining technical acoustic measurements with clinical parameters to improve the diagnostic efficacy of NASH. Methods: We consecutively enrolled 75 patients with clinically suspected nonalcoholic fatty liver disease (NAFLD) who underwent percutaneous liver biopsy in our hospital from June 2020 to December 2021. All cases underwent multiple advanced acoustic measurements for liver such as shear wave dispersion (SWD), shear wave speed (SWS), attenuation imaging (ATI), normalized local variance (NLV), and liver-kidney intensity ratio (Ratio) examination before liver biopsies. A nomogram prediction model combining the technical acoustic measurements and clinical parameters was established and the model is proposed to improve the diagnostic performance of NASH. Results: A total of 75 cases were included in this study. The classification of pathological grade for NASH was as follows: normal liver, (n = 15, 20%), nonalcoholic fatty liver (NAFL), (n = 44, 58.7%), and NASH, (n = 16, 21.3%). There were statistically significant differences in SWS (p = 0.002), acoustic coefficient (AC) (p = 0.018), NLV (p = 0.033), age (p = 0.013) and fasting blood glucose (Glu) (p = 0.049) between NASH and non-NASH. A nomogram model which includes SWS, AC, NLV, age and Glu was built to predict NASH, and the calibration curves showed good calibrations in both training and validation sets. The AUCs of the combined nomogram model for the training set and validation set were 0.8597 and 0.7794, respectively. Conclusion: There were statistically significant differences in SWS, AC, NLV, age and Glu between NASH and non-NASH. A nomogram model which includes SWS, AC, NLV, age and Glu was built to predict NASH. The predictive model has a higher diagnostic performance than a single factor model in the diagnosis of NASH and has good clinical application prospects.

Different Ultrasound Shear Wave Elastography Techniques as Novel Imaging-Based Approaches for Quantitative Evaluation of Hepatic Steatosis-Preliminary Findings

BACKGROUND

Modern ultrasound (US) shear-wave dispersion (SWD) and attenuation imaging (ATI) can be used to quantify changes in the viscosity and signal attenuation of the liver parenchyma, which are altered in hepatic steatosis. We aimed to evaluate modern shear-wave elastography (SWE), SWD and ATI for the assessment of hepatic steatosis.

METHODS

We retrospectively analyzed the US data of 15 patients who underwent liver USs and MRIs for the evaluation of parenchymal disease/liver lesions. The USs were performed using a multifrequency convex probe (1-8 MHz). The quantitative US measurements for the SWE (m/s/kPa), the SWD (kPa-m/s/kHz) and the ATI (dB/cm/MHz) were acquired after the mean value of five regions of interest (ROIs) was calculated. The liver MRI (3T) quantification of hepatic steatosis was performed by acquiring proton density fat fraction (PDFF) mapping sequences and placing five ROIs in artifact-free areas of the PDFF scan, measuring the fat-signal fraction. We correlated the SWE, SWD and ATI measurements to the PDFF results.

RESULTS

Three patients showed mild steatosis, one showed moderate steatosis and eleven showed no steatosis in the PDFF sequences. The calculated SWE cut-off (2.5 m/s, 20.4 kPa) value identified 3/4 of patients correctly (AUC = 0.73, p > 0.05). The SWD cut-off of 18.5 m/s/kHz, which had a significant correlation (r = 0.55, p = 0.034) with the PDFF results (AUC = 0.73), identified four patients correctly (p < 0.001). The ideal ATI (AUC = 0.53 (p < 0.05)) cut-off was 0.59 dB/cm/MHz, which showed a significantly good correlation with the PDFF results (p = 0.024).

CONCLUSION

Hepatic steatosis can be accurately detected using all the US-elastography techniques applied in this study, although the SWD and the SWE showed to be more sensitive than the PDFF.

Impact of Breathing Phase, Liver Segment, and Prandial State on Ultrasound Shear Wave Speed, Shear Wave Dispersion, and Attenuation Imaging of the Liver in Healthy Volunteers

OBJECTIVES

Measurement location and patient state can impact noninvasive liver assessment and change clinical staging in ultrasound examinations. Research into differences exists for Shear Wave Speed (SWS) and Attenuation Imaging (ATI), but not for Shear Wave Dispersion (SWD). The aim of this study is to assess the effect of breathing phase, liver lobe, and prandial state on SWS, SWD, and ATI ultrasound measurements.

METHODS

Two experienced examiners performed SWS, SWD, and ATI measurements in 20 healthy volunteers using a Canon Aplio i800 system. Measurements were taken in the recommended condition (right lobe, following expiration, fasting state), as well as (a) following inspiration, (b) in the left lobe, and (c) in a nonfasting state.

RESULTS

SWS and SWD measurements were strongly correlated (r = 0.805, p < 0.001). Mean SWS was 1.34 ± 0.13 m/s in the recommended measurement position and did not change significantly under any condition. Mean SWD was 10.81 ± 2.05 m/s/kHz in the standard condition and significantly increased to 12.18 ± 1.41 m/s/kHz in the left lobe. Individual SWD measurements in the left lobe also had the highest average coefficient of variation (19.68%). No significant differences were found for ATI.

CONCLUSION

Breathing and prandial state did not significantly affect SWS, SWD, and ATI values. SWS and SWD measurements were strongly correlated. SWD measurements in the left lobe showed a higher individual measurement variability. Interobserver agreement was moderate to good.

How to Identify Advanced Fibrosis in Adult Patients with Non-Alcoholic Fatty Liver Disease (NAFLD) and Non-Alcoholic Steatohepatitis (NASH) Using Ultrasound Elastography-A Review of the Literature and Proposed Multistep Approach

Non-alcoholic fatty liver disease (NAFLD), and its progressive form, non-alcoholic steatohepatitis (NASH), represent, nowadays, real challenges for the healthcare system. Liver fibrosis is the most important prognostic factor for NAFLD, and advanced fibrosis is associated with higher liver-related mortality rates. Therefore, the key issues in NAFLD are the differentiation of NASH from simple steatosis and identification of advanced hepatic fibrosis. We critically reviewed the ultrasound (US) elastography techniques for the quantitative characterization of fibrosis, steatosis, and inflammation in NAFLD and NASH, with a specific focus on how to differentiate advanced fibrosis in adult patients. Vibration-controlled transient elastography (VCTE) is still the most utilized and validated elastography method for liver fibrosis assessment. The recently developed point shear wave elastography (pSWE) and two-dimensional shear wave elastography (2D-SWE) techniques that use multiparametric approaches could bring essential improvements to diagnosis and risk stratification.

Clinical application of preoperative shear wave dispersion for prediction of post liver failure in patients with hepatocellular carcinoma after hepatectomy

OBJECTIVE

The aim in this study was to determine the efficacy of shear wave dispersion (SWD) technique for the prediction of post hepatectomy liver failure (PHLF) in patients with hepatocellular carcinoma after hepatectomy and develop an SWD based risk prediction model.

METHODS & MATERIALS

We prospectively enrolled 205 consecutive patients who were scheduled to undergo hepatectomy for hepatocellular carcinoma (HCC), pre-operative SWD examination, laboratory data and some other clinicopathological tests were collected. The risk factors of PHLF were identified according to univariate and multivariate analysis, a predictive model was established based on logistic regression analyses.

RESULTS

SWD examination was successfully performed in 205 patients. PHLF occurred in 51 patients (24.9%), including 37/11/3 patients with Grade A/B/C, respectively. There was a high correlation between SWD value of liver and liver fibrosis stage (r = 0.873, p < 0.05). Patients with PHLF has a higher median SWD value of liver than patients without PHLF [17.4 vs 14.7 (m/s)/kHz, p < 0.05]. The SWD value of liver, total bilirubin (TB), international normalized ratio of prothrombin time (INR) and splenomegaly were significantly related to PHLF based on the multivariate analysis. A new prediction model (PM) for PHLF was established (PM = -12.918 + 0.183× SWD + 6.668× INR +0.100×TB+1.240×splenomegaly). The optimal cutoff value of SWD for predicting PHLF was 16.7 (m/s)/kHz. The area under the curve (AUC) of the PM for PHLF was 0.833, which was higher than that of SWD, INR, Forns, FIB4, APRI (p < 0.005, respectively).

CONCLUSION

SWD is a promising and reliable method for PHLF prediction in patients with HCC who were undergoing hepatectomy. Compared with SWD, Forns, APRI and FIB-4, PM demonstrate better efficacy for preoperative PHLF prediction.

Fontan-associated liver disease: Diagnosis, surveillance, and management

The Fontan operation is a lifesaving procedure for patients with functional single-ventricle congenital heart disease, where hypoplastic left heart syndrome is the most frequent anomaly. Hemodynamic changes following Fontan circulation creation are now increasingly recognized to cause multiorgan affection, where the development of a chronic liver disease, Fontan-associated liver disease (FALD), is one of the most important morbidities. Virtually, all patients with a Fontan circulation develop liver congestion, resulting in fibrosis and cirrhosis, and most patients experience childhood onset. FALD is a distinctive type of congestive hepatopathy, and its pathogenesis is thought to be a multifactorial process driven by increased nonpulsatile central venous pressure and decreased cardiac output, both of which are inherent in the Fontan circulation. In the advanced stage of liver injury, complications of portal hypertension often occur, and there is a risk of developing secondary liver cancer, reported at young age. However, FALD develops with few clinical symptoms, a surprisingly variable degree of severity in liver disease, and with little relation to poor cardiac function. The disease mechanisms and modifying factors of its development are still not fully understood. As one of the more important noncardiac complications of the Fontan circulation, FALD needs to be diagnosed in a timely manner with a structured monitoring scheme of disease development, early detection of malignancy, and determination of the optimal time point for transplantation. There is also a clear need for consensus on the best surveillance strategy for FALD. In this regard, imaging plays an important role together with clinical scoring systems, biochemical workups, and histology. Patients operated on with a Fontan circulation are generally followed up in cardiology units. Ultimately, the resulting multiorgan affection requires a multidisciplinary team of healthcare personnel to address the different organ complications. This article discusses the current concepts, diagnosis, and management of FALD, with special emphasis on the role of different imaging techniques in the diagnosis and monitoring of disease progression, as well as current recommendations for liver disease surveillance.

Validation of attenuation imaging coefficient, shear wave elastography, and dispersion as emerging tools for non-invasive evaluation of liver tissue in children

Introduction

The number of children with acute and chronic liver disease is rising. Moreover, liver involvement may be limited to subtle changes in organ texture especially in early childhood and some syndromic conditions, such as ciliopathies. Attenuation imaging coefficient (ATI), shear wave elastography (SWE), and dispersion (SWD) are emerging ultrasound technologies providing data about attenuation, elasticity, and viscosity of liver tissue. This additional and qualitative information has been correlated with certain liver pathologies. However, limited data are available for healthy controls and have mainly been raised in adults.

Methods

This prospective monocentric study was conducted at a university hospital with a specialization in pediatric liver disease and transplantation. Between February and July 2021, 129 children aged 0-17.92 years were recruited. Study participants attended outpatient clinics due to minor illnesses excluding liver or cardiac diseases, acute (febrile) infections or other conditions affecting liver tissue and function. ATI, SWE, and SWD measurements were performed on an Aplio i800 (Canon Medical Systems) with an i8CX1 curved transducer by two different investigators with long-standing experience in pediatric ultrasound according to a standardized protocol.

Results

Considering multiple potential covariates, we derived percentile charts for all 3 devices relying on the Lambda-Mu-Sigma (LMS) approach. 112 children were considered for further analysis, excluding those with abnormal liver function and under-/overweight (BMI SDS<-1.96/> 1.96, respectively). Age range was 0-17.92 years (mean 6.89±0.50SD), 58% were male. The mean duration of the ultrasound examination (basic ultrasound plus SWE, SWD, and ATI) was 6.67±0.22 minutes and it was well tolerated in 83% (n=92) of cases. While ATI was related to age, SWD was found to depend on BMI SDS, and SWE on abdominal wall thickness and sex. ATI correlated with neither SWE nor SWD, but SWE was correlated with SWD.

Conclusions

Our study provides norm values and reference charts for ATI, SWE, and SWD considering important covariates including age, sex and, BMI. This may help to implement these promising tools into imaging diagnostics of liver disease and to improve the diagnostic relevance of liver ultrasound. In addition, these noninvasive techniques proved to be time-effective and highly reliable, which make them ideal for application in children.

Stratifying Non-alcoholic Steatohepatitis With the Non-invasive Ultrasound Markers Shear Wave Dispersion Slope and Shear Wave Velocity: An Animal Study

We evaluated the significance of the ultrasound (US) markers shear wave dispersion slope (SWDS) and shear wave velocity (SWV) for identification of non-alcoholic steatohepatitis (NASH) and high-risk NASH; the latter was defined as the presence of steatohepatitis, a non-alcoholic fatty liver disease activity score (NAS) ≥4 or a fibrosis stage ≥2. Thirty-six male Sprague-Dawley (SD) rats were assigned to two groups: the study (n = 30) and control (n = 6) groups. To initiate non-alcoholic steatohepatitis, study group rats were fed a diet deficient in methionine and choline. All rats were examined using ultrasonography to obtain the SWDS and SWV parameters of the liver at the same time points. Fatty liver pathological grades were determined after euthanasia; the livers were categorized in the normal (n = 6), NAFL (non-alcoholic fatty liver) (n = 10) and NASH (n = 20) subgroups based on the NAS scoring system. They were also categorized into subgroups F0 (n = 22), F1 (n = 3), F2 (n = 7) and F3 (n = 4) on the basis of the METAVIR (Meta-analysis of Histological Data in Viral Hepatitis) scoring system. Measurement differences between various grades were evaluated by analysis of variance (ANOVA) or the Mann-Whitney U-test. We used logistic regression to calculate a combination of the two parameters for combined assessment of parameters. The diagnostic value of SWDS, SWV and the two-variable model was determined by receiver operating characteristic (ROC) curve analysis. This analysis revealed stepwise increases in SWDS and SWV with increasing NAFLD severity. The accuracy of SWDS in diagnosing NASH was good (area under the ROC curve [AUC]: 0.88) and was superior to that of SWV (AUC: 0.76). The combination of SWV and SWDS exhibited higher performance (AUC: 0.90). SWV was higher than SWDS in participants with a fibrosis grade ≥2 (high-risk NASH). For identification of high-risk NASH, SWV exhibited the best diagnostic performance (AUC: 0.89), which was equivalent to that of the two-variable model (AUC: 0.88) and slightly higher than that of SWDS (AUC: 0.85). This study indicates that of the US-based markers, SWDS outperforms SWV in identifying NASH in rats and that combining the two markers may increase their clinical utility in guiding NAFLD and NASH treatment.

Shear Wave Dispersion Slope Measured with Shear Wave Dispersion Imaging Is Associated with Variceal Hemorrhage in Cirrhotic Patients

Background and Objectives: Portal hypertension (PH), as the main consequence of cirrhosis, leads to the development of gastroesophageal varices (GEVs). Variceal hemorrhage (VH) caused by the rupture of GEVs is a life-threatening emergency. Thus, the prediction of VH risk is considerably important. Our pilot study aimed to identify the risk factors of variceal hemorrhage (VH) in cirrhosis. Materials and Methods: Cirrhotic patients were prospectively included and divided into two groups according to the presence or absence of VH. Conventional ultrasound and shear wave dispersion (SWD) imaging were conducted to detect the portal vein diameter, spleen diameter, ascites, liver stiffness (LS) and shear wave dispersion slope (SWDS). The laboratory tests were recorded, including platelets (PLT), alanine transaminase (ALT), aspartate aminotransferase (AST), total bilirubin (TBIL) and albumin (ALB). The risk factors of VH were screened using univariate analyses and identified using multivariate logistic regression. The ROC curves were used to assess diagnostic accuracy. Comparisons between AUCs were performed using the Delong method. Results: Sixty-five patients with 22 VHs were finally included. The SWDS, spleen diameter and ascites were identified as independent risk factors for VH. The SWDS showed good performance for diagnosing VH (AUC = 0.768, 95% CI: 0.647−0.864), and sensitively identified 95.5% (95% CI: 77.2%−99.9%) of patients with VH. Including the three risk factors in multivariate logistic regression, we obtained a formula for diagnosing VH: −20.749 + 0.804 × SWDS + 0.449 × spleen diameter + 1.803 × ascites (no ascites = 0, ascites = 1). Comparison of AUCs revealed that the formula (AUC = 0.900, 95% CI: 0.800−0.961) performed better than LS, SWDS, and spleen diameter in diagnosing VH (p < 0.001; p < 0.05; p < 0.05). Conclusions: SWDS is a sensitive parameter for assessing the risk of VH. Combining the SWDS, spleen diameter and ascites resulted in good diagnostic accuracy.

Efficacy of shear wave dispersion imaging for viscoelastic assessment of the liver in acute graft-versus-host disease rats

BACKGROUND

To investigate the feasibility of using shear wave dispersion (SWD) imaging to evaluate hepatic acute graft-versus-host disease (aGVHD) in a rat model.

METHODS

To establish an aGVHD model, 30 Wistar rats were subjected to bone marrow transplantation, 10 Fischer 344 rats were used as donors, and 6 Wistar rats were used as the control group. Each week, 6 rats were randomly chosen and divided into groups of 1 week (1 w) to 5 weeks (5 w). For each subgroup, the rats received a clinical index assessment and shear wave dispersion (SWD) examination with 2 quantitative values, shear wave (SW) speed and SWD slope. The histological characteristics were then used as the reference standard to divide the rats into the aGVHD group and the no aGVHD (nGVHD) group.

RESULTS

In the 2 weeks (2 w) group, only SWD slope [median: 7.26, interquartile range (IQR): 7.04 to 7.31] showed a significant increase in the measured value (P<0.05). The value of the 3 weeks (3 w) group (median: 7.88, IQR: 7.84 to 8.49) significantly increased compared with the 2 w value (P<0.05). Although the value increased gradually from week 3 to week 5, it had no statistical significance (P>0.05). The SW speed [mean ± standard deviation (SD): 1.54±0.11, 95% confidence interval (CI): 1.48 to 1.59] and SWD slope (mean ± SD: 8.29±0.56, 95% CI: 7.99 to 8.59) of the aGVHD group were higher than those of the control group and the nGVHD group (P<0.001). The correlation of SWD slope with pathological grade was the highest (r=0.798, P<0.01), followed by SW speed (r=0.785, P<0.01), and the correlation of clinical index with pathological grade was the lowest (r=0.751, P<0.01). In addition, the area under the receiver operating characteristic (ROC) curve (AUC) value of aGVHD using the SWD slope was 0.844 (95% CI: 0.67 to 0.95, sensitivity: 93.75%, specificity: 78.57%), which was higher than the AUC of both SW speed and clinical index, and the difference was statistically significant compared to the AUC of the clinical index.

CONCLUSIONS

The SWD slope could show significant abnormalities earlier than SW speed and clinical index and is also more consistent with the change in aGVHD severity level. The SWD slope may help in detecting hepatic aGVHD during ultrasound SWD examination.

Viscoelasticity assessment for in vivo quantification of muscle contusion injury in rats using shear wave elastography

The aim of the study described here was to investigate the role of viscoelasticity in assessing muscle fibrosis and inflammation in a rat model of contusion using quantitative shear wave elastography (SWE). Unilateral gastrocnemius muscle contusion was induced in 32 male rats using an impactor apparatus. The contralateral muscles served as the control group. SWE was applied to the control group and rats 1, 3, 14 and 21 d after successful modeling (each time point group, n = 8). Histologic features were used as reference standards. The degree of fibrosis was moderately correlated with shear wave speed (r = 0.53), whereas the degree of inflammation was well correlated with shear wave dispersion (SWD) slope (r = 0.74). The area under the receiver operating characteristic curve (AUC) for the dispersion slope for muscle inflammation and fibrosis assessment was 0.87 (95% confidence interval: 0.705-0.963), which exceeded that of the shear wave speed (0.68, 95% confidence interval: 0.494-0.834). The larger decline in dispersion slope in the fibrotic stage than in the inflammation stage (1-d group vs. 14-d group or 21-d group, p &lt; 0.05) indicated better predictive performance than the shear wave speed.

US Shear-Wave Elastography Dispersion for Characterization of Chronic Liver Disease

Background Little is known about the benefits of the use of dispersion slope (DS) as a viscosity-related parameter derived from two-dimensional (2D) shear-wave elastography (SWE) in the stratification of hepatic pathologic stages. Purpose To evaluate whether DS as an additional parameter can improve the diagnostic performance in detecting liver necroinflammation, fibrosis, and steatosis. Materials and Methods In this prospective study, consecutive participants with chronic liver disease who underwent liver biopsy and 2D SWE were recruited between July 2019 and September 2020. DS and liver stiffness (LS) measurements were obtained with use of a 2D SWE system immediately before biopsy. The biopsy specimens were assessed to obtain the scores of fibrosis, necroinflammation, and steatosis. Differences in the area under the receiver operating characteristic curve (AUC) were used to compare the diagnostic performance of DS, LS, and a combination of DS and LS. Results There were 159 participants evaluated (among them, 79 participants with chronic hepatitis B and 11 participants with nonalcoholic fatty liver disease). The distributions of DS values among various necroinflammatory activities (P = .02) and fibrosis stages (P < .001) were different. Moreover, DS was only associated with fibrosis after subgroup analysis based on the fibrosis stages and necroinflammatory activities (P < .001). The AUCs of DS in detecting clinically significant fibrosis (fibrosis stage ≥F2), cirrhosis (fibrosis stage of F4), and moderate to severe necroinflammatory activity (necroinflammatory activity ≥A2) were 0.72 (95% CI: 0.64, 0.79), 0.71 (95% CI: 0.63, 0.78), and 0.64 (95% CI: 0.55, 0.71), respectively. The differences of AUCs were not apparent for the DS and LS combination model after excluding DS (fibrosis stage ≥F2: 0.00 [95% CI: 0.00, 0.01], fibrosis stage of F4: -0.01 [95% CI: -0.02, 0.00], and necroinflammatory activity ≥A2: 0.00 [95% CI: 0.00, 0.01]). Conclusion The addition of dispersion slope derived from two-dimensional shear-wave elastography did not improve the diagnostic performance in detecting liver fibrosis, necroinflammation, or steatosis in patients with primarily viral hepatitis. ClinicalTrials.gov registration no.: NCT03777293 © RSNA, 2022 Online supplemental material is available for this article.

Clinical Feasibility of Shear Wave Dispersion Slope for Noninvasive Diagnosis of Nonalcoholic Steatohepatitis in Patients With Morbid Obesity: Preliminary Results Using US Shear Wave Elastography

ABSTRACT

We aimed to investigate the clinical feasibility of shear wave dispersion slope for assessing nonalcoholic steatohepatitis (NASH) in patients with morbid obesity before bariatric surgery.This prospective study collected data from 25 participants who received liver biopsy during bariatric surgery between February 2019 and December 2020. All participants underwent ultrasonography shear wave elastography before surgery and shear wave speed and shear wave dispersion slope were measured. Liver specimens were evaluated by 1 pathologist scored histologically for nonalcoholic fatty liver disease (NAFLD). Ultrasonography measurements were compared according to histopathologic findings. Diagnostic performance in differentiating NASH from NAFLD was evaluated using the area under the receiver operating characteristic curve (AUC). Median shear wave speed (1.48 vs 1.62 m/s, P = 0.014) and dispersion slope (8.40 vs 11.80 [m/s]/kHz, P = 0.004) were higher in NASH group than in NAFLD group. Shear wave dispersion slope tended to increase step by step as the severity of activity grade (P = 0.032) and hepatic fibrosis (P = 0.015) increased. The AUC of shear wave dispersion slope for differentiating NASH from NAFLD (AUC, 0.83; 95% confidence intervals, 0.66-1.00) was higher than that of shear wave speed (AUC, 0.78; 95% CI, 0.60-0.97), although it did not reach statistical significance (P = 0.729). Shear wave dispersion slope could be a feasible tool for assessing NASH in patients with morbid obesity.

Ultrasound Shear Wave Elastography, Shear Wave Dispersion and Attenuation Imaging of Pediatric Liver Disease with Histological Correlation

Aim: To evaluate the feasibility of multiple ultrasound markers for the non-invasive characterization of fibrosis, inflammation and steatosis in the liver in pediatric patients. Materials and methods: The quantitative ultrasound measures shear wave elastography (SWE), shear wave dispersion (SWD) and attenuation imaging (ATI) were compared and correlated with percutaneous liver biopsies and corresponding measures in a control cohort. Results: The median age of the 32 patients was 12.1 years (range 0.1−17.9), and that of the 15 controls was 11.8 years (range: 2.6−16.6). Results: There was a significant difference in SWE values between histologic grades of fibrosis (p = 0.003), with a positive correlation according to the grade (r = 0.7; p < 0.0001). Overall, a difference in SWD values between grades of inflammation was found (p = 0.009) but with a lack of correlation (r = 0.1; p = 0.67). Comparing inflammation grades 0−1 (median:13.6 m/s kHz [min; max; 8.4; 17.5]) versus grades 2−3 (16.3 m/s kHz [14.6; 24.2]) showed significant differences between the groups (p = 0.003). In the 30 individuals with a steatosis score of 0, ATI was measured in 23 cases with a median value of 0.56 dB/cm/MHz. Conclusion: Comprehensive ultrasound analysis was feasible to apply in children and has the potential to reflect the various components of liver affection non-invasively. Larger studies are necessary to conclude to what extent these image-based markers can classify the grade of fibrosis, inflammation and steatosis.

A Kalman Filter Approach for Estimating Tendon Wave Speed from Skin-Mounted Accelerometers

Shear wave tensiometry is a noninvasive approach for assessing in vivo tendon forces based on the speed of a propagating shear wave. Wave speed is measured by impulsively exciting a shear wave in a tendon and then assessing the wave travel time between skin-mounted accelerometers. Signal distortion with wave travel can cause errors in the estimated wave travel time. In this study, we investigated the use of a Kalman filter to fuse spatial and temporal accelerometer measurements of wave propagation. Spatial measurements consist of estimated wave travel times between accelerometers. Temporal measurements are the change in wave arrival at a fixed accelerometer between successive impulsive taps. The Kalman filter substantially improved the accuracy of estimated wave speeds when applied to simulated tensiometer data. The variability of estimated wave speed was reduced by ~55% in the presence of random sensor noise. It was found that increasing the number of accelerometers from two to three further reduced wave speed errors by 45%. The use of redundant accelerometers (>2) also improved the robustness of wave speed measures in the presence of uncertainty in accelerometer location. We conclude that the use of a Kalman filter and redundant accelerometers can enhance the fidelity of using shear wave tensiometers to track tendon wave speed and loading during movement.

Shear wave elastography and shear wave dispersion imaging in primary biliary cholangitis-a pilot study

Background

Primary biliary cholangitis (PBC) is a chronic liver disease that can lead to liver fibrosis and cirrhosis. Two-dimensional shear wave elastography (2D-SWE) is a modern technique for fibrosis assessment. However, data regarding its performance in PBC is sparse. We aimed to characterize severity of liver disease in PBC patients using non-invasive 2D-SWE and the new methods of attenuation imaging (ATI) and shear wave dispersion imaging (SWD).

Methods

Twenty two PBC patients were examined with 2D-SWE, SWD and ATI, alongside established non-invasive fibrosis and steatosis assessment methods as well as liver function tests.

Results

Median 2D-SWE values were 1.48 m/s (range, 1.14-2.13 m/s) and 6.7 kPa (range, 3.8-14.7 kPa), respectively. Median SWD, ATI, transient elastography (TE) and controlled attenuation parameter (CAP) values were 13.9 m/s/kHz (range, 11.6-21 m/s/kHz), 0.57 dB/cm/MHz (range, 0.5-0.68 dB/cm/MHz), 7 kPa (range, 3.7-14.6 kPa), and 208 dB/m (range, 107-276 dB/m), respectively. 2D-SWE displayed a significant correlation with spleen length, platelet count, non-invasive fibrosis scores (FIB-4, APRI) and with TE. SWD correlated with alkaline phosphatase (ALP) levels, which is a prognostic marker in PBC.

Conclusions

Our findings add further evidence that 2D-SWE is a reliable method for fibrosis assessment in PBC. Even though the cohort size was small, the correlation of SWD with the prognostic marker ALP suggests a potentially valuable role of this new non-invasive method in evaluating liver disease activity in PBC.

Quantification of Nerve Viscosity Using Shear Wave Dispersion Imaging in Diabetic Rats: A Novel Technique for Evaluating Diabetic Neuropathy

Objective

Viscoelasticity is an essential feature of nerves, although little is known about their viscous properties. The discovery of shear wave dispersion (SWD) imaging has presented a new approach for the non-invasive evaluation of tissue viscosity. The present study investigated the feasibility of using SWD imaging to evaluate diabetic neuropathy using the sciatic nerve in a diabetic rat model.

Materials and Methods

This study included 11 diabetic rats in the diabetic group and 12 healthy rats in the control group. Bilateral sciatic nerves were evaluated 3 months after treatment with streptozotocin. We measured the nerve cross-sectional area (CSA), nerve stiffness using shear wave elastography (SWE), and nerve viscosity using SWD imaging. The motor nerve conduction velocity (MNCV) was also measured. These four indicators and the histology of the sciatic nerves were then compared between the two groups. The performance of CSA, SWE, and SWD imaging in distinguishing the two groups was assessed using receiver operating characteristic (ROC) analysis.

Results

Nerve CSA, stiffness, and viscosity in the diabetic group was significantly higher than those in the control group (all p < 0.05). The results also revealed a significantly lower MNCV in the diabetic group (p = 0.005). Additionally, the density of myelinated fibers was significantly lower in the diabetic group (p = 0.004). The average thickness of the myelin sheath was also lower in the diabetic group (p = 0.012). The area under the ROC curve for distinguishing the diabetic neuropathy group from the control group was 0.876 for SWD imaging, which was significantly greater than 0.677 for CSA (p = 0.030) and 0.705 for SWE (p = 0.035).

Conclusion

Sciatic nerve viscosity measured using SWD imaging was significantly higher in diabetic rats. The viscosity measured using SWD imaging performed well in distinguishing the diabetic neuropathy group from the control group. Therefore, SWD imaging may be a promising method for the evaluation of diabetic neuropathy.

Quantitative Evaluation of Hepatic Steatosis Using Advanced Imaging Techniques: Focusing on New Quantitative Ultrasound Techniques

Nonalcoholic fatty liver disease, characterized by excessive accumulation of fat in the liver, is the most common chronic liver disease worldwide. The current standard for the detection of hepatic steatosis is liver biopsy; however, it is limited by invasiveness and sampling errors. Accordingly, MR spectroscopy and proton density fat fraction obtained with MRI have been accepted as non-invasive modalities for quantifying hepatic steatosis. Recently, various quantitative ultrasonography techniques have been developed and validated for the quantification of hepatic steatosis. These techniques measure various acoustic parameters, including attenuation coefficient, backscatter coefficient and speckle statistics, speed of sound, and shear wave elastography metrics. In this article, we introduce several representative quantitative ultrasonography techniques and their diagnostic value for the detection of hepatic steatosis.

Shear-Wave Dispersion Slope of the Liver: Effect of Study Protocol and Ascites on the Measurement Applicability

This study aimed to evaluate the shear-wave dispersion (SWD) scanning protocol including the minimum number of measurements and better size of the region of interest (ROI), as well as the influence of ascites on the measurement applicability. Patients who had undergone serial SWD examinations between July 2019 and December 2020 were included. In patients with chronic liver disease (group A), two different ROI sizes were applied, and at least 10 measurements were repeated to determine the minimum number of measurements and better ROI size. In patients with liver failure (group B), failure and unreliable results were compared between patients with and without ascites. A minimum of five measurements when using a 20-mm ROI and six measurements when using a 10-mm ROI were required. Compared with using a 20-mm ROI, a 10-mm ROI showed a higher unreliable rate. The failure and unreliable rates of SWD in patients with ascites were significantly higher than those in patients without ascites. SWD examination required at least five measurements when using a 20-mm ROI and six measurements when using a 10-mm ROI. A larger ROI was associated with higher reliability, and ascites influenced the failure and reliability of the SWD measurement.

Inflammatory activity affects the accuracy of liver stiffness measurement by transient elastography but not by two-dimensional shear wave elastography in non-alcoholic fatty liver disease

BACKGROUND

In patients with non-alcoholic fatty liver disease (NAFLD), the impact of the severity of steatosis and inflammatory activity on the accuracy of liver stiffness measurement (LSM) by transient elastography (TE) and by two-dimensional shear wave elastography (2D-SWE) in staging liver fibrosis is still debated and scarce. We aimed to focus on this aspect.

METHODS

We prospectively studied 104 patients requiring biopsy for the assessment of NAFLD. We used ordinary least squares regression to test for differences in the association between fibrosis and LSM by TE and 2D-SWE when other factors (steatosis and inflammatory activity) are considered.

RESULTS

Among 104 patients, 102 had reliable LSM by TE, and 88 had valid LSM by 2D-SWE. The association between fibrosis based on histology and LSM was significantly stronger when 2D-SWE assessed LSM compared to TE (Spearman's correlation coefficient of .71; P < .001 vs .51, P < .001; Z = 2.21, P = .027). Inflammatory activity was an independent predictor of LSM by TE but not of LSM by 2D-SWE. After controlling for fibrosis, age, sex and body mass index, the inflammatory activity and the interaction between inflammatory activity and fibrosis independently explained 11% and 13% of variance in LSM by TE respectively. Steatosis did not affect the association of fibrosis and LSM by either method.

CONCLUSION

Inflammatory activity on histology significantly affects LSM by TE, but not LSM by 2D-SWE in NAFLD. LSM by 2D-SWE reflects liver fibrosis more accurately than LSM by TE. Furthermore, the severity of steatosis on histology did not influence the association of LSM and fibrosis by either elastography method.

Sources of Variability in Shear Wave Speed and Dispersion Quantification with Ultrasound Elastography: A Phantom Study

There is a growing interest in quantifying shear-wave dispersion (SWD) with ultrasound shear-wave elastography (SWE). Recent studies suggest that SWD complements shear-wave speed (SWS) in diffuse liver disease diagnosis. To accurately interpret these metrics in clinical practice, we analyzed the impact of operator-dependent acquisition parameters on SWD and SWS measurements. Considered parameters were the acquisition depth, lateral position and size of the region of interest (ROI), as well as the size of the SWE acquisition box. Measurements were performed using the Canon Aplio i800 system (Canon Medical Systems, Otawara, Tochigi, Japan) and four homogeneous elasticity phantoms with certified stiffness values ranging from 3.7 to 44 kPa. In general, SWD exhibited two to three times greater variability than SWS. The acquisition depth was the main variance-contributing factor for both SWS and SWD, which decayed significantly with depth. The lateral ROI position contributed as much as the acquisition depth to the total variance in SWD. Locations close to the initial shear-wave excitation pulse were more robust to biases because of inaccurate probe-phantom coupling. The size of the ROI and acquisition box did not introduce significant variations. These results suggest that future guidelines on multiparametric elastography should account for the depth- and lateral-dependent variability of measurements.

Assessment of chronic liver disease by multiparametric ultrasound: results from a private practice outpatient facility

PURPOSE

To assess chronic liver disease (CLD) using multiparametric US in a private practice setting in a cohort of patients with increased skin-to-liver distance.

METHODS

110 consecutive patients with increased skin-to-liver distance scheduled for US assessment of CLD were reviewed for study completion time, liver stiffness values (LS), attenuation imaging, and shear wave dispersion slope. The ROI was placed 2 cm below the liver capsule. The study included patients with NAFLD/NASH (68), hepatitis C (30), prior Fontan surgery (1), elevated liver function tests (5), alcohol abuse (3), hepatitis B (2), and primary biliary cirrhosis (1). IQR/M values were obtained. Comparison of less experienced sonographers (LES) and more experienced sonographers (MES) were evaluated through Student's t test for independent data. Pearson coefficient r of correlation among quantitative variables was calculated.

RESULTS

The mean time to perform the exam was 129.7 ± 62.1 s. There was a statistically significant difference between LES and MES. The mean IQR/M for LS was 12.3 ± 5.5% m/s. Overall, in a cohort of difficult patients, 4.5% of LS values were not reliable. Fat quantification using attenuation imaging had a mean value of 0.60 ± 0.15 dB/cm/MHz (range 0.35-0.98 cm/dB/MHz) with an IQR/M of 14.7 ± 9.2%. Less reliable measurements of steatosis were obtained in 4.5% of patients. The mean shear wave dispersion slope was 12.74 ± 4.05 (m/s)/kHz (range 7.7-27.5 (m/s)/kHz) with an IQR/M of 38.7 ± 20.2% (range 3-131%). 20.9% of patients had values suggestive of compensated advanced chronic liver disease (cACLD).

CONCLUSION

Multiparametric US can provide assessment of CLD in less than 3 min in most patients and identify patients at risk for cACLD.

Multiparametric US for Identifying Patients with High-Risk NASH: A Derivation and Validation Study

Background Nonalcoholic fatty liver disease (NAFLD) is common in the general population but identifying patients with high-risk nonalcoholic steatohepatitis (NASH) who are candidates for pharmacologic therapy remains a challenge. Purpose To develop a score to identify patients with high-risk NASH, defined as NASH with an NAFLD activity score (NAS) of 4 or greater and clinically significant fibrosis (stage 2 [F2] or higher). Materials and Methods This was a cross-sectional secondary analysis of data prospectively collected between April 2017 and March 2019 for a group of patients with NAFLD in Japan (Japan NAFLD, the derivation data set) with contemporaneous two-dimensional shear-wave elastography and biopsy-proven NAFLD (age range, 20-89 years). Three US markers (liver stiffness [LS, measured in kilopascals], attenuation coefficient [AC, measured in decibels per centimeter per megahertz], and dispersion slope [DS, measured in meters per second per kilohertz]) were determined, together with aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels and the AST-to-ALT ratio. The best-fit multivariate logistic regression model for identifying patients with high-risk NASH was determined. Diagnostic performance was assessed by using the area under the receiver operating characteristic curve (AUC). The findings were validated in an independent data set (Korea NAFLD; age range, 20-78 years). Results The Japan NAFLD data set included 111 patients (mean age, 53 years ± 18 [standard deviation]; 57 men), 84 (76%) with NASH. The Korea NAFLD data set included 102 patients (mean age, 48 years ± 18; 43 men), 55 (36%) with NASH. The most predictive model (LAD NASH score) combined LS, AC, and DS. Performance was satisfactory in both the derivation sample (AUC, 0.86; 95% CI: 0.79, 0.93) and the validation sample (AUC, 0.88; 95% CI: 0.80, 0.95). The LAD NASH score showed a positive predictive value of 86.5% and a negative predictive value of 87.5% for high-risk NASH in the derivation sample. Conclusion A score combining three US markers may be useful for noninvasive identification of patients with high-risk nonalcoholic steatohepatitis for inclusion in clinical trials and pharmacologic therapy. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Lockhart in this issue.

Reduction of Shear Wave Elastography but Not Shear Wave Dispersion After Successful Hepatitis C Treatment With Direct-Acting Antiviral Agents

OBJECTIVES

Successful antiviral treatment in patients with hepatitis C can lead to reduced liver stiffness. In this study, we attempted to compare 2-dimensional (2D) shear wave elastography (SWE), shear wave dispersion (SWD), and attenuation imaging (ATI) with transient elastography (TE) and the controlled attenuation parameter (CAP) in patients under direct-acting antiviral (DAA) therapy.

METHODS

Patients with chronic hepatitis C infection undergoing DAA therapy from January 2017 to June 2020 were retrospectively examined. The results of 2D SWE, SWD, ATI, TE, and CAP were recorded before and 12 weeks after the completion of DAA therapy.

RESULTS

A total of 122 patients with a median age of 61 years were investigated; among them, 121 (99.2%) achieved a sustained virologic response at 12 weeks after DAA therapy. Fibrosis 4, the aspartate aminotransferase-to-platelet ratio index, 2D SWE, and TE were reduced after DAA therapy. The CAP was increased; however, SWD and ATI showed no statistically significant changes after DAA therapy. Two-dimensional SWE and TE were strongly correlated (r = 0.885-0.897; P < .001). Albumin and the baseline liver stiffness measurement were independent factors of liver stiffness measurement changes after DAA therapy.

CONCLUSIONS

Direct-acting antiviral therapy can significantly decrease liver stiffness (using both 2D SWE and TE) but not SWD and ATI values in patients with hepatitis C. An increased CAP is also observed after DAA therapy.

A Multidisciplinary Approach to Evaluate the Presence of Hepatic and Cardiac Abnormalities in Patients with Post-Acute COVID-19 Syndrome-A Pilot Study

(1) Background: Patients suffering from the novel coronavirus 2019 (COVID-19) disease could experience several extra-pulmonary involvements, including cardiovascular complications and liver injury. This study aims to evaluate the presence of cardiac and liver alterations in patients with post-acute COVID-19 syndrome using transthoracic echocardiography (TTE) and liver elastography (LE). (2) Methods: A total of 97 subjects recovering from COVID-19, attending the hospital's specialized outpatient clinic for persisting symptoms at 3 to 11 weeks after the acute illness, were included in this study. They all had a basal COVID-19 assessment, and subsequently, a clinical evaluation, laboratory tests, TTE, and LE. (3) Results: considering the presence of pulmonary injury during COVID-19, patients were divided into two groups. Although none of them had altered systolic function, we evidenced pulmonary hypertension, diastolic dysfunction, increased liver stiffness, viscosity, and steatosis in around one-third of the patients, with significantly higher values in subjects with pulmonary injury compared to those without. (4) Conclusion: persisting symptoms characterizing the post-acute COVID-19 syndrome could be explained by residual cardiac and hepatic lesions, which were worse in more severe COVID-19 forms. These patients may be at risk of developing liver fibrosis and cardiac alterations and should be investigated in the first 12 weeks after the onset of the infection.

An initial trial of quantitative evaluation of autoimmune pancreatitis using shear wave elastography and shear wave dispersion in transabdominal ultrasound

BACKGROUND/OBJECTIVES

We aimed to examine therapeutic efficacy and prognosis prediction of autoimmune pancreatitis (AIP) using shear wave elastography (SWE) and shear wave dispersion (SWD) in transabdominal ultrasound (US).

METHODS

The subjects were 23 patients with diffuse type 1 AIP who underwent SWE and SWD, and 34 controls with a normal pancreas. Elasticity and dispersion were defined as the pancreatic elastic modulus (PEM) and dispersion slope, respectively. PEM and dispersion slope were compared between AIP and control cases, and the short-term therapeutic effect and long-term prognosis were examined.

RESULTS

PEM (30.9 vs. 6.6 kPa, P < 0.001) and dispersion slope (15.3 vs. 13.0 (m/sec)/kHz, P = 0.011) were significantly higher in AIP cases than in controls. Among the 17 AIP patients followed-up in two weeks after treatment, these parameters were 12.7 kPa and 10.5 (m/sec)/kHz with median decrease rate of 37.2% and 32.8%, respectively, which were significantly higher than the change in the size of pancreatic parenchyma (14.4%, P = 0.026). Fourteen of these subjects were followed up for >12 months, during which 2 had relapse; diabetes improved in 5 and worsened in 2; in 60% of cases, the pancreatic parenchyma was atrophied. The % change in PEM after two weeks was tended to be higher in non-atrophy cases.

CONCLUSION

SWE and SWD measurement in US may be useful for quantitative assessment of AIP and evaluation of short-term treatment efficacy.

Shear Wave Elastography in the Detection of Sinusoidal Obstruction Syndrome in Adult Patients Undergoing Allogenic Hematopoietic Stem Cell Transplantation

Hepatic sinusoidal obstruction syndrome (SOS), also known as veno-occlusive disease (VOD) can be a life-threatening complication after hematopoietic stem cell transplantation (HSCT). Diagnosis is often difficult and traditionally based on clinical parameters. Shear wave elastography (SWE) is a modern non-invasive liver stiffness measurement technique using ultrasound. In this monocentric study, we evaluated the role of SWE in diagnosing SOS/VOD in 63 adult patients undergoing HSCT from February 2020 to August 2020 in real world settings. Three patients developed SOS/VOD. This was accompanied by an increase in shear wave velocity in all three patients, indicating that this method may contribute to establishing the diagnosis SOS/VOD after HSCT.

Accuracy of Two-Dimensional Shear Wave Elastography and Attenuation Imaging for Evaluation of Patients With Nonalcoholic Steatohepatitis

BACKGROUND & AIMS

We evaluated the accuracy of a multiparametric approach using attenuation imaging and 2-dimensional shear wave elastography (2D-SWE) for the detection of steatosis and fibrosis in patients with nonalcoholic fatty liver disease (NAFLD).

METHODS

We studied 102 patients with increased levels of liver enzymes or suspicion of NAFLD, examined by attenuation imaging and 2D-SWE, immediately before biopsy collection and analysis (reference standard), from January 2018 to July 2019. We collected data on the attenuation coefficient (dB/cm/MHz) from attenuation imaging, liver stiffness measurements, and shear wave dispersion slope (SWDS, [m/s]/kHz) from 2D-SWE. Multivariate linear regression analysis was performed to identify factors associated with each parameter. Diagnostic performance was determined from area under the receiver operating curve (AUROC) values.

RESULTS

The attenuation coefficient was associated with steatosis grade (P < .01) and identified patients with steatosis grades S1 or higher, S2 or higher, and S3 or higher, with AUROC values of 0.93, 0.88, and 0.83, respectively. Liver stiffness associated with fibrosis stage (P < .01) and lobular inflammatory activity was the only factor associated with SWDS (P < .01). SWDS detected inflammation grades I1 or higher, I2 or higher, and I3 or higher with AUROC values of 0.89, 0.85, and 0.78, respectively. We developed a risk scoring system to detect steatohepatitis based on the attenuation coefficient (score of 1 for 0.64 < attenuation coefficient ≤ 0.70; score of 2 for 0.70 < attenuation coefficient ≤ 0.73; and score of 3 for attenuation coefficient >0.73) and SWDS (score of 2 for 10.5 [m/s]/kHz < SWDS ≤ 11.7 [m/s]/kHz; and score of 3 for SWDS >11.7 [m/s]/kHz), using an unweighted sum of each score. Based on histopathology analysis, 55 patients had steatohepatitis. Risk scores correlated with NAFLD activity score (rho = 0.73; P < .01). Our scoring system identified patients with steatohepatitis with an AUROC of 0.93-this value was significantly higher than that of other parameters (P < .05), except SWDS (AUROC, 0.89; P = .18).

CONCLUSIONS

In the evaluation of patients with suspected NAFLD, the attenuation coefficient can identify patients with steatosis and liver stiffness can detect fibrosis accurately. SWDS was associated significantly with lobular inflammation. We developed a risk scoring system based on the attenuation coefficient and SWDS that might be used to detect steatohepatitis.

Efficacy of shear wave elastography for assessment of liver function in patients with heart failure

AIMS

Liver dysfunction is important for prognosis in heart failure (HF). Shear wave elastography (SWE), which is a novel ultrasound technique for charactering tissues, has been used in liver diseases. However, clinical implication of SWE, including dispersion slope, remains unknown in heart diseases. This study aimed to evaluate the efficacy of SWE assessing liver function in the severity of HF.

METHODS AND RESULTS

We enrolled 316 consecutive patients with or suspected heart diseases, who were classified according to the American College of Cardiology Foundation/American Heart Association stage of HF, including 37 with Stage A, 139 with Stage B, 114 with Stage C, and 26 with Stage D, and 45 normal subjects. Elasticity and dispersion slope of shear wave were assessed according to the HF stage. Elasticity and dispersion slope were not elevated in normal subjects and patients with Stage A. Elasticity was slightly increased from Stage A to Stage C and was remarkably elevated in Stage D (normal: 5.2 ± 1.1 kPa, Stage A: 5.4 ± 1.2 kPa, Stage B: 6.4 ± 1.8 kPa, Stage C: 7.8 ± 3.5 kPa, and Stage D: 17.7 ± 12.7 kPa), whereas dispersion slope was gradually increased from Stage A to Stage D (normal: 9.7 ± 1.7m/s/kHz, Stage A: 10.4 ± 1.6m/s/kHz, Stage B: 11.7 ± 2.4m/s/kHz, Stage C: 13.2 ± 3.4m/s/kHz, and Stage D: 17.6 ± 5.6 m/s/kHz). In the early HF stage, dispersion slope was elevated. In the advanced HF stage, both elasticity and dispersion slope were elevated. Liver function test abnormalities were observed only from Stage C or Stage D.

CONCLUSIONS

Dispersion slope could detect early liver damage, and the combination of elasticity and dispersion slope could clarify the progression of liver dysfunction in HF. SWE may be valuable to manage therapeutic strategies in patients with HF.

2D shear wave elastography is better than transient elastography in predicting post-hepatectomy complication after resection

OBJECTIVES

Both transient elastography (TE) and 2D shear wave elastography (SWE) are accurate methods to evaluate liver fibrosis. We aimed to evaluate the diagnostic performance of 2D-SWE in predicting post-hepatectomy complication and to compare it with TE.

METHODS

We prospectively enrolled 125 patients with liver tumors. Liver stiffness (LS) (kilopascal [kPa]) was measured using both TE and 2D-SWE before surgery. All post-operative complication was evaluated using the comprehensive complication index (CCI), and CCI ≥ 26.2 was defined as severe complication. Logistic regression analysis was performed to identify predictive factors for severe complication. Receiver operating characteristic analysis was used to evaluate the diagnostic performance of TE/2D-SWE in detecting liver fibrosis and severe complication.

RESULTS

Severe complication developed in 18 patients. The median LS in patients with severe complication was significantly higher for both 2D-SWE (11.4 kPa vs. 7.0 kPa, p < 0.001) and TE (8.9 kPa vs. 6.2 kPa, p = 0.009). LS obtained from 2D-SWE was a significant factor correlated with severe complication (odds ratio: 1.27 per kPa [1.10-1.46], p = 0.001). The diagnostic performance of 2D-SWE was significantly higher than that of TE in detecting both ≥F3 (p = 0.024) and F4 (p = 0.048). The area under the curve of 2D-SWE to predict severe complication was 0.854, significantly higher than 0.692 of TE (p = 0.004). The optimal cut-off LS from 2D-SWE to predict severe complication was 8.6 kPa, with sensitivity of 88.9% (16/18) and specificity of 73.8% (79/107).

CONCLUSION

LS obtained from 2D-SWE was a significant predictive factor for severe complication, and 2D-SWE showed significantly a better diagnostic performance than TE in detecting liver fibrosis and severe complication.

KEY POINTS

• The diagnostic performance of 2D-SWE was significantly higher than that of TE in detecting both ≥ F3 (AUC: 0.853 vs. 0.779, p = 0.024) and F4 (AUC: 0.929 vs. 0.872, p = 0.048). • Liver stiffness value obtained from 2D-SWE was a significant factor correlated with the development of severe complication defined as CCI ≥ 26.2 after hepatic resection for liver tumors (odds ratio: 1.27 per kPa [1.10-1.46], p = 0.001). • 2D-SWE provided significantly a better diagnostic performance in predicting severe complication after hepatic resection than TE (AUC for 2D-SWE: 0.853 vs. AUC for TE: 0.692, p = 0.004).

Shear Wave Dispersion Predicts Liver Fibrosis and Adverse Outcomes in Patients with Heart Failure

Background: It has been recently reported that liver stiffness assessed by transient elastography reflects right atrial pressure (RAP) and is associated with worse outcomes in patients with heart failure (HF). However, the relationship between shear wave dispersion (SWD, a novel indicator of liver viscosity) determined by abdominal ultrasonography and RAP, and the prognostic impact of SWD on HF patients have not been fully examined. We aimed to clarify the associations of SWD with parameters of liver function test (LFT) and right heart catheterization (RHC), as well as with cardiac events such as cardiac death and worsening HF, in patients with HF. Methods: We performed abdominal ultrasonography, LFT and RHC in HF patients (n = 195), and followed up for cardiac events. We examined associations between SWD and parameters of LFT and RHC. Results: There were significant correlations between SWD and circulating levels of direct bilirubin (R = 0.222, p = 0.002), alkaline phosphatase (R = 0.219, p = 0.002), cholinesterase (R = −0.184, p = 0.011), and 7S domain of collagen type IV (R = 0.177, p = 0.014), but not with RAP (R = 0.054, p = 0.567) or cardiac index (R = −0.015, p = 0.872). In the Kaplan–Meier analysis, cardiac event rate was significantly higher in the high SWD group (SWD ≥ 10.0 (m/s)/kHz, n = 103) than in the low SWD group (SWD < 10.0 (m/s)/kHz, n = 92; log-rank, p = 0.010). In the Cox proportional hazard analysis, high SWD was associated with high cardiac event rates (hazard ratio, 2.841; 95% confidence interval, 1.234–6.541, p = 0.014). In addition, there were no interactions between SWD and all subgroups, according to the subgroup analysis. Conclusions: SWD assessed by abdominal ultrasonography reflects liver fibrosis rather than liver congestion, and is associated with adverse prognosis in HF patients.

Shear wave elastography for evaluation of the urgency of liver transplantation in pediatric patients with biliary atresia

BACKGROUND

To investigate the role of two-dimensional shear wave elastography (2D-SWE) in the preoperative evaluation of pediatric patients with biliary atresia awaiting liver transplantation.

METHODS

Among a total of 152 pediatric patients enrolled in this single-institution prospective study between March 2018 and August 2019, 143 patients (age range, 4-97 months; median age, 7 months; 84 males, 59 females) who underwent successful routine ultrasound examination, SWE examination, and blood test before liver transplantation were included in the final analysis. The values of liver stiffness measured by SWE were compared with ultrasound and blood test parameters by Spearman's correlation analysis.

RESULTS

The overall median liver stiffness with 2D-SWE was 29.0 ± 10.9 kPa, with a range of 9.0-53.3 kPa. The success rate of 2D-SWE measurements was 98.0% (149/152). Liver stiffness measurement (LSMs) had no significant correlation with gender, age, weight, and height of the pediatric recipients. LSMs were correlated with ultrasound parameters including portal vein (PV) maximum velocity, PV direction, hepatic artery resistance index (HARI), spleen diameter, ascites, and blood test parameters (albumin level, platelet count level, and international normalized ratio). In the pediatric recipients with hepatofugal PV flow, high HARI (HARI ≧ 0.90), and ascites, or without Kasai operation, LSMs were significantly higher (P < .05).

CONCLUSIONS

SWE is feasible and valuable for assessing liver damage in children with biliary atresia awaiting liver transplantation and might be used as selection criteria for children in need of priority access to liver transplantation.