Changes in forearm muscle stiffness in relation to grip strength.

Longitudinal Assessment of Quantitative Metrics for Skeletal Muscle Health Using 3D Rotational Shear Wave Elasticity Imaging in the Vastus Lateralis.

Assessment of the uncertainty of shear wave speed measurements in ultrasound elastography.

Screening patients with liver fibrosis and identifying those at risk of developing advanced liver fibrosis is of clinical interest. Shear wave elastography (SWE), a promising non-invasive screening tool used to distinguish healthy tissue from diseased tissue, measures tissue shear wave speed (SWS) to describe tissue stiffness and identify liver fibrosis. However, considerable variations in the reported results have been found. We propose that the heterogeneity of the liver tissue background, such as the presence of fatty liver tissue and the preferred local orientation of the scarred fibrotic liver tissues embedded into the liver parenchyma, may contribute to the uncertainty in SWE measurements. Therefore, this study aims to systematically investigate four cofounding factors, the size, volume fraction, and orientation of the fibrotic inclusions, as well as the fatty background, using computer simulations, to describe the multifaceted impact on SWS variability (i.e., SWS standard deviation). The simulations implemented in this preliminary study demonstrated that both fibrosis and fatty background impact the SWS STD and that the SWS STD distributions do not follow a Gaussian distribution. While the SWS STD increased with fibrosis size and volume fraction, the SWS STD decreased as the fatty background increased. The shape of the distribution did not follow a consistent trend across fibrosis inclusion levels, fibrosis sizes, fibrosis orientations, and percent fatty background for either the Mean SWS or the SWS STD. The current study provided evidence that the current clinical guidelines, regarding cut-off values for the different METAVIR Fibrosis stages, overestimate the fibrosis levels in the presence of steatosis.

Shear wave elastography quantifies tissue stiffness. This study aimed to assess the stiffness of the flexor tendons of the fingers under physiological conditions in healthy individuals and compare the results with cases of tendon rupture. Twenty-two healthy volunteers were enrolled in this study. Shear wave speed (SWS) measurements of the flexor tendons were obtained in three positions (rest, extension, and flexion) by two independent observers. The effects of laterality, fingers, time (repeating the measurements at 0, 2.5, and 5 min after initial positioning in extension), age, and sex were analyzed. Additionally, eight patients with tendon rupture after primary repair were assessed, and their SWS values were compared with those of healthy volunteers. We observed statistically significant differences in SWS values between rest and extension, as well as between rest and flexion. Tendon size also showed a statistically significant effect. Excellent inter-rater reliability was found between the two observers' measurements. Notably, the difference in SWS between a ruptured tendon and the contralateral healthy tendon of the same digit was considerably greater than the difference between any two healthy fingers. This study establishes a reference standard for SWS values in healthy flexor tendons and demonstrates the potential of shear wave elastography as a diagnostic tool for detecting tendon rupture in vivo. A standardized protocol is required for its reliability and reproducibility. Diagnostic IV.

Objective. The biomechanical properties of tissue are of interest in preclinical cancer research where their changes can be related to treatment response. Preclinical shear wave elastography (SWE) may be used to measure the viscoelastic properties of tumours although their small size presents challenges. Here we study the repeatability of 3D shear wave speed (SWS) measurements using continuous harmonic vibrations under different conditions in a preclinicalin-vivotumour model.Approach. Subcutaneous tumours (MDA-MB-231) grown on the flank of athymic nude mice (n= 4) were imaged using a system comprising a research ultrasound scanner and a mechanically translated 18 MHz linear imaging probe. Shear waves were induced in the tumours by external contactors driven at three different vibration frequencies (500, 700 and 1000 Hz), in two orientations (top and side), sedated in separate sessions using injectables or breathable anaesthesia. Measurements were repeated over three consecutive days. 3D tumour volume outlines were used to determine the spatial transformation required to register sets of 3D SWS data, allowing measurement of repeatability of the 3D pattern of SWS using normalised cross correlation.Main results. Analysis of variance of mean SWS measurements (2-5 m s-1) revealed significant differences between the tumours (p< 0.001), and vibration frequencies (p< 0.001). Mean SWS was not significantly affected by the choice of anaesthetic or tumour orientation. Intratumoural SWS spatial distributions showed improved day-to-day repeatability when obtained from the same tumour (+76% increase in normalised cross correlation compared to different tumours), the same orientation (+39% compared to different orientations), and when using a side orientation at 500 Hz (+18% compared to top orientations). Breathing motion with gaseous anaesthesia was found to be slower (∼1.5 s vs ∼0.5 s period) but with greater amplitude (<0.6 vs <0.3 mm) than with injectable. Side orientation was found to reduce respiratory motion amplitude. SWS measurements and their repeatability however were not significantly affected by the choice of anaesthesia, and therefore variation in breathing motion.Significance. SWE with continuous vibration is a repeatable and feasible technique forin-vivopreclinical use.

Elastic properties of materials can be measured by observing shear wave propagation following localized, impulsive excitations and comparing the spatiotemporal signals with signals calculated using a mechanical model of the material. These calculations are difficult in anisotropic materials because of the complex relations among the material symmetries, propagation directions, and wave polarizations. This study presents a new analytic model of wave propagation in an incompressible transversely isotropic (ITI) material, which is a commonly used model for anisotropic biological tissues such as skeletal muscle. The model solves the Cauchy equation of motion in the spatial and temporal Fourier domains by separating the system response function that relates the excitation force and shear wave signal into two terms corresponding to shear horizontal and shear vertical shear wave polarizations. Sample results are reported for an ITI material with model parameters similar to parameters measured in in vivo muscle and for model parameters determined by fitting the model to experimentally measured shear wave speeds in in vivo muscle. Calculation times for the analytic model are significantly shorter compared to similar calculations based on finite element simulations or Green's function calculations, and thus, the analytic model is well-suited for iterative fitting of model parameters.

ObjectiveTo evaluate the diagnostic potential of viscosity (Vi) imaging and shear wave elastography (SWE) of the tibial nerve in diabetic peripheral neuropathy (DPN).Materials and MethodsThis prospective study enrolled 40 patients with type II diabetes mellitus (T2DM) accompanied by DPN, 40 T2DM patients without DPN, and 40 healthy controls between January 2025 and April 2025. The bilateral tibial nerves were examined using SWE and Vi imaging to measure shear wave speed (Cs, m/s) and Vi (Pa·s). The reference standards for the DPN diagnosis comprised clinical examination, electromyography, and quantitative sensory testing. Diagnostic performance was assessed using receiver operating characteristic curve analysis and by calculating sensitivity and specificity at the optimal cutoff values for Cs and Vi. The areas under the curve (AUCs) were compared using DeLong’s test.ResultsOn the right side, the DPN group exhibited significantly higher Csmean (median: 4.05 m/s [interquartile range: 3.30–4.51] vs. 3.25 m/s [2.95–3.45]; P < 0.05) and Vimean (median: 3.51 Pa·s [2.70–4.58] vs. 2.43 Pa·s [2.20–2.97]; P < 0.05) compared to the non-DPN group, with similar trends observed on the left side. Both Csmean (AUC = 0.826 [95% confidence interval: 0.725–0.902]) and Vimean (AUC = 0.765 [0.657–0.852]) demonstrated favorable diagnostic performance for DPN, without a significant difference (P = 0.144). Combining Csmean and Vimean resulted in a sensitivity of 62.5% (25/40), a specificity of 95.0% (38/40), and an AUC of 0.828 (0.727–0.903), without significant improvement compared to Csmean or Vimean alone (P = 0.573 and 0.148, respectively).ConclusionVi imaging quantifies nerve Vi in DPN and offers a novel, non-invasive diagnostic approach to distinguish patients with DPN from those without the condition. However, viscoelastic imaging does not provide greater diagnostic value than SWE.

When heart disease progresses to heart failure, congestion develops in various organs, including the liver and kidneys. Although organ congestion is a critical factor closely associated with the prognosis of heart failure, a simple and quantitative method for evaluating the degree of organ congestion has not yet been established. Two-dimensional shear wave elastography (2D-SWE) is a noninvasive ultrasound technique that can estimate tissue stiffness by measuring shear wave speed (SWS), an index of tissue viscoelasticity, and dispersion slope (DS), which reflects tissue viscosity alone. This study aimed to assess the utility of SWS and DS in evaluating hepatic and renal congestion in transfused dogs by performing 2D-SWE before and after blood transfusion. The ratio of the short diameter (SD) to the long diameter (LD) of the caudal vena cava (CVC SD/LD) was used as an index of congestion. Twenty transfusions were administered to 17 dogs. After transfusion, both the liver and kidney SWS and DS, along with CVC SD/LD, significantly increased. A moderate positive correlation was observed between the CVC SD/LD and liver SWS (r=0.781, p<0.01) and kidney SWS (r=0.744, p<0.01). Conversely, a strong positive correlation was found between the CVC SD/LD and liver DS (r=0.900, p<0.01) and kidney DS (r=0.850, p<0.01). These findings suggest that 2D-SWE may be a valuable tool for assessing liver and kidney congestion, with DS potentially serving as a reliable indicator of congestion.

Objective.This study aimed to establish a link between the microstructure of simulated fibrotic liver tissues and the measured shear wave speed (SWS) variability using a machine-learning (ML)-based approach.Approach. Fibrotic liver tissues were simulated using biphasic random fields. The underlying microstructure of the simulated fibrotic liver pathology (sFLP) was characterized using spatial pattern distribution analysis. A ML technique was implemented to identify top-rated spatial characteristic (SC) features and provide context for SWS variability, ultimately enabling us to use the SWS variability to infer its underlying tissue microstructure. Different combinations of top three features were tested to understand the sensitivity of our parameter selection.Main results. Even though volume fraction and the SWS estimates were highly correlated, percent inclusion by itself as a single predictive factor was not an accurate indicator of the SWS estimates. For the sFLP tissue models developed for the current study, none of the individual SC features were able to predict the SWS estimates. Regardless of the top features identified, the model prediction correlation remained constant for each prediction iteration. However, even though the top three features across the five ML-based prediction iterations had different specific names, the features were all highly correlated.Significance. The findings from our current study suggest that while the percent inclusion rate was highly correlated to the mean SWS and SWS-STD, the percent inclusion rate alone cannot predict mean SWS or SWS-STD. mean SWS and SWS-STD provide unique information regarding the sFLP tissue microstructure, and both SWS estimates should be considered when analyzing fibrotic liver tissue. Consistent feature identification with previous published studies demonstrated that the sFLPs developed for this study may be representative of real-world patient data.

BackgroundEarly detection and treatment of tendinopathy may prevent progression to partial tears or complete rupture. Shear wave elastography (SWE) may help address the need for better tendon pathology characterization. This study aimed to quantify the effect of structural damage in an ex vivo animal tendinopathy model using SWE.MethodsForty-two porcine flexor tendons were injected with a 0.05-mL bolus of 1.5% collagenase solution to induce focal structural damage without surface tears. Control tendons were injected with saline (n = 42). Twenty-one tendons from each group were incubated at 37 °C for 3.5 h, while the remaining 21 from each group were incubated for 7 h. Each group was then divided into three groups of seven, and tendon incisions were made at 25%, 50%, and 75% of the tendon thickness. Tendons were mechanically stretched axially during simultaneous collection of SWE at the injection site.ResultsThere were significant differences in shear wave speed (SWS) (saline > collagenase) at 3.5-h incubation (p < 0.001) and 7-h incubation (p < 0.001). Additionally, there was a significant difference in SWS between tendons cut at 25% and tendons cut at 50% and 75% (p = 0.040 and p = 0.001, respectively). Collagenase-treated tendons ruptured at a lower force than saline-treated tendons at both incubation times (both p < 0.001) when controlling for cut depth. Tendons treated with collagenase ruptured at a lower force than the saline control group at each cut thickness (all p < 0.001) controlling for incubation time.ConclusionIn a controlled ex vivo porcine model, SWE can be used to detect structural damage associated with tendinopathy.Relevance statementShear wave elastography can be used to show differences in abnormal tendons that may be translatable to clinical use as an adjunctive measure of tendon elasticity and injury.Key PointsTendon abnormality was quantitatively characterized using shear wave elastography in an ex vivo porcine experimental model.Shear wave speed was an accurate imaging biomarker for tendon health.Shear wave elastography was effective at detecting the extent of tendon damage.Tendons with decreased shear wave speed measurements rupture at smaller applied mechanical force.Graphical

Background/Objectives: The quadratus lumborum (QL) muscle is a key structure involved in patients with low back pain (LBP). Since the discriminative capability of morphological descriptors is uncertain and considering the high prevalence of myofascial trigger points and the poor reliability of manual palpation in this condition, developing a reliable procedure for assessing the QL's tenderness is needed for facilitating the diagnosis and monitoring changes over time. We aimed to analyze the intra- and inter-examiner reliability of SWE for calculating the QL tenderness in patients with LBP. Methods: Using a convex transducer, longitudinal shear wave elastography (SWE) images of the QL muscle were acquired bilaterally twice in 52 volunteers with moderate LBP and disability by one experienced examiner and one novel examiner to measure shear wave speed and Young's modulus as stiffness metrics. Results: Intra-examiner reliability estimates demonstrated high consistency independently of the examiner's experience (intraclass correlation coefficients (ICCs) > 0.930) for both metrics. However, experienced examiners showed smaller minimal detectable changes. Additionally, inter-examiner reliability was lower, with ICCs ranging from 0.57 to 0.68, and significant differences in mean values between examiners (p < 0.01) were found. Conclusions: This procedure exhibited excellent intra-examiner reliability for assessing QL muscle stiffness in patients suffering LBP, indicating high repeatability of measurements when performed by the same examiner. In addition, experienced examiners demonstrated greater sensitivity in detecting real changes not attributed to measurement errors. However, inter-examiner reliability was moderate, highlighting the need for consistent examiner use to avoid measurement variability and averaging multiple measurements to enhance the accuracy.

Magnetic resonance elastography (MRE) provides detailed maps of tissue stiffness, helping to diagnose various health conditions, but requires the use of expensive clinical MRI scanners. Our approach utilizes compact, cost-effective portable MR sensors that offer bulk characterization of material properties in a region of interest close to the surface (within 1-2cm). This accessible instrument could enable routine monitoring and prevention of diseases not readily evaluated with conventional tools. The method was tested on tissue-mimicking phantoms with varying stiffness. The gels were excited with acoustic pulses (one cycle of a sinusoidal waveform) at a fixed distance from the MR sensor. A series of delays between acoustic excitation and MR signal detection allowed time for the pulse to travel to the sensitive region. The "arrival time" of the shear wave, determined by the time-dependent MR signal response, was used to calculate the shear wave speed. MR measurements of shear wave speed were compared with optical sensor measurements and manufacturer-tabulated values, aligning with expected relative differences between samples. A portable MR-based transient elastometry technique for measuring tissue elasticity was developed and demonstrated on tissue-mimicking phantoms. Future improvements include using a new portable magnet to investigate depth-dependent changes in elasticity in stratified samples and integrating MR relaxation and diffusion measurements for comprehensive tissue analysis. This approach can complement conventional MRE in applications where a portable, affordable, and localized assessment of tissue stiffness is required.

Shear wave elastography (SWE) is an advanced ultrasound technique that assesses tissue stiffness by measuring shear wave speed (SWS) produced after an acoustic impulse. It includes bidimensional (2D-SWE) and focal point (pSWE) methods, allowing qualitative and quantitative analysis of tissue stiffness. This study aimed to describe the elastographic features of testicular abnormalities in dogs, supported by histological findings. Eighteen dogs with testicular abnormalities underwent B-mode ultrasound, power and color Doppler ultrasound, 2D-SWE, and pSWE before orchiectomy. Five cryptorchid testes were excluded and thirty-one testes (12 normal, 7 with leydigomas, 6 with seminomas, 1 with a round cell tumor, and 5 with orchitis) were examined. Normal testes, lesions, and adjacent healthy tissues (no evident ultrasound changes, NEUC) were sampled. Testicular abnormalities presented SWS values of 1.05-4.89 m/s (2D-SWE) and 1.35-5.31 m/s (pSWE). Significant differences were observed among normal testes, NEUC areas, and those with orchitis, leydigomas, and seminomas by both 2D-SWE and pSWE. Normal testes were significantly softer than ones with leydigomas, seminomas, and orchitis, and NEUC areas also had different SWS values compared to those with tumors and orchitis (p < 0.05). However, SWE techniques lacked specificity in differentiating between orchitis and tumors. Diagnostic accuracy of SWE techniques for testicular lesions remains challenging and requires further investigation to fully address its clinical potential.

Ultrasound shear wave elasticity imaging (SWEI) quantifies the mechanical properties of soft tissue by relating measurements of shear wave speed (SWS) to a material model. Many SWEI algorithms estimate the time-of-flight (TOF) over some fixed distance along a given trajectory and calculate the wave velocity as the ratio of that distance over the TOF. To balance spatial resolution and SWS precision, most high-resolution 2D-SWEI algorithms average together multiple noisy velocity estimates to generate the final SWS. However, velocity calculated over a fixed distance with an estimated TOF can be prone to divide-by-near-zero (DBNZ) errors, especially as the true TOF approaches zero. The reciprocal of velocity, slowness, will never experience DBNZ errors as long as the fixed distance over which TOF is estimated is greater than zero. In this work, we modify an existing 2D-SWEI algorithm to be based on point estimates of slowness. We propose a statistical model assuming normal TOF distributions and use it to evaluate the accuracy and the precision of the velocity- and slowness-based SWS algorithms in Monte Carlo simulations. We then extend our analysis of TOF data to empirically describe the bounds of the proposed model in the presence of speckle bias. Finally, we evaluate both algorithms in heterogeneous media and quantify the achievable lesion conspicuity across a range shear wave SNR and SWS algorithm reconstruction parameters. We conclude that slowness-based SWS can achieve similar accuracy and precision as velocity-based SWS at less than one tenth the TOF SNR with no additional computational cost. For a fixed shear wave and TOF SNR in isotropic homogeneous media, we experimentally demonstrate a reduction in bias greater than 5% and reduction in variability greater than 15%. We also demonstrate that the slowness-based approach achieves superior or equal lesion conspicuity as the velocity based approach - regardless of imaging condition or algorithm parameters.

Effect of joint angle positioning on shearwave speed and variability with ultrasound shearwave elastography in asymptomatic Achilles and patellar tendons

Background Attenuation coefficient (AC) and shear-wave speed (SWS) are established US markers for assessing patients with metabolic dysfunction-associated steatotic liver disease (MASLD), while shear-wave dispersion slope (DS) is not. Purpose To assess the relationship between the multiparametric US imaging markers DS, AC, and SWS and liver histopathologic necroinflammation in patients with MASLD. Materials and Methods This international multicenter prospective study enrolled consecutive patients with biopsy-proven MASLD between June 2019 and March 2023. Before biopsy, all participants underwent multiparametric US, and measurements of DS, AC, and SWS were obtained. Multivariable linear regression analyses were performed to assess the association of clinical variables and imaging markers with pathologic findings. The diagnostic performance of imaging markers for determining inflammation grade, steatosis grade, and fibrosis stage was assessed using the area under the receiver operating characteristic curve (AUC). Results A total of 124 participants (mean age, 53 years ± 15 [SD]; 62 males) were evaluated. In multivariable regression, lobular inflammation was associated with DS (regression coefficient, 0.06; P = .02), alanine aminotransferase level (regression coefficient, 0.002; P = .002), and Hispanic or Latino ethnicity (regression coefficient, -0.68; P = .047), while steatosis was associated with AC (regression coefficient, 3.66; P < .001) and fibrosis was associated with SWS (regression coefficient, 2.02; P < .001) and body mass index (regression coefficient, 0.05; P = .02). DS achieved an AUC of 0.72 (95% CI: 0.63, 0.82) for identifying participants with inflammation grade A2 or higher (moderate to severe inflammation). AC showed excellent performance for identifying participants with grade S1 (mild) or higher steatosis (AUC, 0.92 [95% CI: 0.87, 0.97]), while SWS showed excellent performance for identifying participants with fibrosis stage F2 or higher (clinically significant fibrosis) (AUC, 0.91 [95% CI: 0.86, 0.96]). Of the three US markers, SWS showed the highest AUC (0.81 [95% CI: 0.74, 0.89]) for the diagnosis of metabolic dysfunction-associated steatohepatitis. Conclusion Of the three US imaging markers (DS, AC, and SWS), DS was most associated with lobular inflammation grade at histologic examination and demonstrated fair diagnostic performance in distinguishing moderate to severe lobular inflammation. ClinicalTrials.gov Identifier: NCT04012242 Published under a CC BY 4.0 license. Supplemental material is available for this article. See also the editorial by Yin in this issue.

Assessment of the effects of direct myofascial release in the lateral gastrocnemius muscle of tennis athletes using ShearWave™ elastography

Ultrasound shear-wave elastography has emerged as a promising non-invasive technique for assessing tissue stiffness and elasticity, enabling the detection and monitoring of pathological changes for disease diagnosis, treatment and monitoring. Crawling Waves Sonoelastography (CWS) is an elastography approach that generates mechanical waves to measure Shear Wave Speed (SWS). However, current estimation techniques for CWS present important limitations such as the presence of artifacts leading to potential diagnostic inaccuracies. The paper proposes two quality parameters for CWS, the coefficient of variation and the normalized spectral deviation, which can be evaluated and used to discard regions where SWS measurements are inaccurate. The proposed quality parameters are tested on gelatin homogeneous and heterogeneous phantoms. Evaluation is carried out across frequencies ranging from 200 Hz to 500 Hz. Results show that both methods can help reduce the variation in SWS and increase the CNR by up to 6dB while reducing the bias by up to 20%.

This study aimed to evaluate the inter-examiner reliability of shear wave elastography (SWE) for measuring cervical multifidus (CM) muscle stiffness in asymptomatic controls and patients with chronic neck pain. A longitudinal observational study was conducted to assess the diagnostic accuracy of a procedure. SWE images, following a detailed procedure previously tested, were acquired by two examiners (one novice and one experienced) to calculate the shear wave speed (SWS) and Young’s modulus. The painful side was examined for the experimental cases while the side examined in the control group was selected randomly. Data analyses calculated the intra-class correlation coefficients (ICCs), absolute errors between examiners, standard errors of measurement, and minimal detectable changes. A total of 125 participants were analyzed (n = 54 controls and n = 71 cases). The Young’s modulus and SWS measurements obtained by both examiners were comparable within the asymptomatic group (both, p > 0.05) and the chronic neck pain group (both, p > 0.05). Nonetheless, a notable distinction was observed in the absolute error between examiners for shear wave speed measurements among patients with neck pain, where a significant difference was registered (p = 0.045), pointing to a sensitivity in measurement consistency affected by the presence of chronic neck pain. ICCs demonstrated moderate-to-good reliability across both groups, with ICC values for asymptomatic individuals reported as >0.8. Among the chronic neck pain patients, ICC values were slightly lower (>0.780). The study revealed moderate-to-good consistency, highlighting the practicality and generalizability of SWE.