Current status of musculoskeletal application of shear wave elastography

Effect of focused ultrasound on shearwave production in a hyperelastic media

Focused ultrasound (FUS) is an emerging noninvasive modality for treating various medical conditions. It encompasses both therapeutic and diagnostic applications, utilizing ultrasound waves at different intensities. In diagnostic modalities, ultrasound energy is deposited at the focus to generate acoustic radiation force (ARF), resulting in the generation of shear stress and waves, which are utilized in elastography to evaluate the mechanical properties of tissue. However, therapeutic modalities utilizing higher intensities may lead to elevated shear stress levels. The shear stress induced in the focal region during FUS procedures can potentially affect biological processes, such as cell membrane permeability and gene regulation. To better understand the mechanical stress generated during FUS procedures, we developed a finite element model (FEM) to simulate sonication using a single-element FUS transducer. We modeled soft tissue using a neo-Hookean hyperelastic constitutive behavior, offering a more realistic representation of tissue behavior compared to the linear elasticity assumptions commonly employed in ultrasound-based elastography techniques. Operational parameters were varied to simulate different acoustic powers of the transducer by applying mechanical surface pressure at various operating frequencies. The model depicted FUS wave propagation with amplified surface pressure at the focus, generating relevant focal pressures consistent with clinical setups. The focal beam size within the soft tissue material was characterized and exhibited dependency on the operating frequency of the transducer. As the FUS wave converged at the focus, an ARF was exerted, resulting in displacement and induced shear stress around the focal region, which were quantified. The displacement and shear stress that were analyzed were dependent on the applied transducer surface pressure. These findings deepen the understanding of the mechanics of low-intensity FUS and provide valuable insights into its shear-related effects due to displacement and deformation of the media.

Patellar height changes sequentially after medial open wedge high tibial osteotomy: Evaluation using shear wave elastography

BACKGROUND

This study was performed to evaluate changes in patellar tendon tissue after medial open wedge high tibial osteotomy (MOWHTO) using shear wave elastography (SWE) and to clarify the factors contributing to patellar height changes after MOWHTO.

METHODS

The study cohort comprised 24 knees of 24 patients. Patellar tendon length, thickness, and elasticity were evaluated using SWE preoperatively, 2 weeks postoperatively, and 3, 6, and 12 months postoperatively. The Caton-Deschamps index (CDI) was also measured at these time points. Lower limb alignment and factors related to sequential changes in patellar height were evaluated.

RESULTS

The CDI was significantly different between preoperatively and 2 weeks postoperatively and between 2 week postoperatively and 3, 6, and 12 months postoperatively (p < 0.05 for all) The patellar tendon length at 12 months postoperatively was significantly shorter than that at 2 weeks postoperatively. The postoperative patellar tendon thickness was thicker than preoperative patellar tendon at all sites. The postoperative patellar tendon thickness significantly increased from preoperatively at middle and distal sites. The only factor associated with Δpre-post2WCDI (preCDI - post2WCDI) was ΔMPTA(medial proximal tibial angle) (postoperative MPTA - preoperative MPTA) (p = 0.042). The significant predictor of Δpost2W-post12MCDI was Δpost2W-post12 M distal elasticity (p = 0.022).

CONCLUSION

Patellar height changed sequentially after MOWHTO. The factors that caused patellar height change were related to the change in patellar tendon quality after OWHTO.

Assessing Supraspinatus Tendon Elasticity at Different Locations and Loading Conditions Using Ultrasound Shear-Wave Elastography in Young Healthy Population

Objective: This prospective study aims to investigate the feasibility of Shear-Wave Elastography (SWE) for assessing the mechanical properties of the normal supraspinatus tendon and describing the elastographic features of the supraspinatus tendon under different loading conditions and positions. Methods: Twenty healthy volunteers (10 males and 10 females, aged 18-25 years) were examined by SWE using an 18-4 MHz linear array transducer. The elasticity of the supraspinatus tendon of the dominant hand was measured at three distinct locations: the insertion, middle, and myotendinous junction of the tendon. These measurements were taken under various conditions, including non-loading and the application of 5, 10, and 20 lb forces at five different positions. Results: The average elasticity was 69.2 ± 26.5 kilopascals across all positions and forces, with the middle part of the tendon exhibiting the highest elasticity (72.6 ± 6.2 kPa). An ascending trend in elasticity was observed by increasing the applied load, and the highest elasticity was observed with a 20 lb load. Determining the normal elasticity of the tendon is an important clinical implication, as understanding what is normal is essential for identifying pathological conditions. Conclusions: SWE is a feasible and promising technology for the collection of data on how the supraspinatus tendon behaves under loading conditions. There is a need for further study to better understand tendon response to activity and resultant injuries.

Do functionality, strength, vascularization, inflammatory and biopsychosocial status improve by biopsychosocial model-based exercise in SSc?

OBJECTIVES

This study aimed to investigation of the effects of the Cognitive Exercise Therapy Approach [Bilişsel Egzersiz Terapi Yaklaşımı (BETY)], a supervised biopsychosocial model-based exercise intervention, on functionality, muscle strength, vascularization, anti-inflammatory and biopsychosocial status in SSc patients.

METHODS

Thirty-seven SSc patients were included. Twenty of them were recruited into the study group (SG) undergoing BETY group exercise sessions three times a week for 3 months and seventeen were in the control group (CG) following a home exercise program. Assessment tools were the Modified Rodnan Skin Score (mRSS), Scleroderma HAQ (SHAQ), Modified Hand Mobility in Scleroderma (mHAMIS), Duruoz Hand Index (DHI), Six-Min Walk Test (6-MWT), skeletal muscle strength measurements using an isokinetic dynamometer (Biodex System 3 Pro), Shear Wave Elastography, ELISA kits (for tumour necrosis factor-alpha, Interleukin-6, IL-10, serum irisin level), BETY-Biopsychosocial Questionnaire (BETY-BQ), Hospital Anxiety and Depression Scale (HADS) and Short Form-36 (SF-36).

RESULTS

The SG demonstrated improvements in SHAQ, mHAMIS, 6-MWT, BETY-BQ, HADS and SF-36 values, excluding the DHI scores (P < 0.05). In contrast, CG showed worsening in SHAQ-general scleroderma symptoms and HADS scores compared with SG (P < 0.05). IL-10 and TNF-alpha increased in both groups, also various vascular parameters were significantly different changed in SG than CG (P < 0.05). Muscle strength values improved in the SG but decreased in the CG, however, this was statistically not significant (P > 0.05).

CONCLUSION

BETY can be recommended as a non-pharmacological approach to the disease management of SSc patients.

Enhanced diagnosis and severity assessment of carpal tunnel syndrome using combined shear wave elastography and cross-sectional area analysis: A prospective case-control study

Carpal tunnel syndrome (CTS) is a prevalent neuropathy resulting from median nerve compression, typically diagnosed through electrodiagnostic studies. Shear wave elastography (SWE) has emerged as an essential imaging technique, especially in evaluating tissue elasticity, which could enhance the diagnosis and severity assessment of CTS. This study aimed to examine the combined effect of the median nerve's cross-sectional area (CSA) and elasticity assessed through SWE in diagnosing CTS and evaluating its severity. A total of 50 participants were involved in this prospective study, with 99 wrists analyzed (51 affected by CTS and 48 normal controls). Measurements of both CSA and elasticity were taken at the carpal tunnel inlet. The findings indicated that CSA and elasticity were considerably higher in CTS patients than in the controls. The combined parameter of CSA ×  elasticity outperformed other measures for differentiating between normal and CTS cases (Area Under the Curve 0.91, sensitivity 0.90, specificity 0.83, cutoff 753.7 kPa·mm²). This combined metric also showed potential for distinguishing CTS severity levels, particularly between mild and severe cases. Although CSA and elasticity alone had limitations in severity classification, their combined values illustrated significant distinctions across severity levels. Integrating SWE with CSA notably improves diagnostic accuracy for CTS and shows potential for severity grading. This approach offers a more detailed evaluation of the structural and mechanical changes in the median nerve, potentially enhancing both the diagnosis and management of CTS.

Preliminary study on assessing skin changes in Henoch-Schönlein purpura patients using high-frequency ultrasound and shear wave elastograph

Henoch-Schönlein purpura (HSP) is a prevalent allergic vasculitis. We aimed to investigate the characteristics of skin lesions and assess the degree of the skin damage in HSP patients using high-frequency ultrasound (HFUS) and shear wave elastography (SWE). By leveraging these imaging modalities, we sought to provide an objective and quantitative method for the clinical assessment of HSP, offering valuable insights for the evaluation and management of this condition. Thirty patients diagnosed with HSP were included in the study group (Group B). Among them, patients were further categorized into three subgroups based on the timing of evaluation: Group B1 consisted of patients at the time of admission, Group B2 included patients at the time of discharge, and Group B3 comprised patients at the time of discontinuation of treatment. The control group (Group A) consisted of 30 healthy individuals from the Health Management Center. General clinical data were systematically gathered from both groups. 20 MHz HFUS and SWE were used to assess the thickness and stiffness of the dermis and hypodermis on the left anterior tibial skin of both groups. Laboratory parameters, including WBC, CRP, ESR, and IgE, were documented for the case group, and their correlations with MEmean, MEmax, and MEmin were analyzed. It was found that compared to Group A, the thickness and stiffness of the dermis and hypodermis were significantly increased in the Groups B1 and B2, with dermal stiffness also increased in the Group B3 (all P < 0.05). However, no significant differences were observed in the thickness of the dermis and hypodermis, as well as in the stiffness of hypodermal between the Group B3 and Group A (all P > 0.05). This study showed that the overall skin thickness and stiffness of HSP lesions increased compared to group A. HFUS and SWE can monitor the clinical efficacy of HSP and quantitatively assess the extent of skin involvement in HSP patients, providing clinicians with a precise ultrasound basis for more objective evaluation of treatment outcomes.

Feasibility of shear wave elastography (2D -SWE) to evaluate cristalline lens in healthy dogs

BACKGROUND

2D shear wave elastography (2D SWE) is an emerging technique in veterinary medicine able to assess tissue stiffness in a non-invasive way. Nowadays no report is yet available about its application in assessing the mechanical properties of canine lenses.

OBJECTIVES

This study aimed to evaluate the repeatability and reproducibility of 2D SWE in assessing normal lens elasticity in healthy and ageing dogs.

METHODS

Trans-corneal lens 2D SWE was performed under physical restraint on 33 dogs by two operators who collected triplicate kPa and m/s measures, with the aim to assess reproducibility and reliability of the technique, followed by the evaluation of eventual difference of stiffness in different ages (G1 < 1.5 years, G2 1.5 years-7 years and G3 > 7 years). The project has been approved by the CEISA Ethical Committee (Prot. N. 12/2019 361 CEISA). Written informed consent was obtained by all the owners.

RESULTS

Mean elasticity values were respectively 4.78 ± 1.48 m/s and 74.9 ± 43.7 kPa for the left eye and 4.45 ± 0.98 m/s and 75.9 ± 43.6 kPa for the right eye. Despite a slight difference observed in the measurements obtained in m/s between the two operators, the intra-observer assessment was excellent in the overall population of dogs for both values in KPa and m/s, as well as the inter-observer one (ICC > 0.75). All the sCV% computed evidence a low measurement dispersion (< 12%). Mean lens stiffness for G1 was 3.1 ± 0.5 m/s and 28.9 ± 9.3 kPa, for G2 4.61 ± 0.62 m/s and 65 ± 18.4 kPa and for G3 6.46 ± 0.36 m/s and 126 ± 14.5 kPa; a significant difference P (< 0.001) was detected between all the groups.

CONCLUSIONS

It can be concluded that 2D SWE is a rapid and non-invasive US-based technique able to assess lens mechanical properties in companion animals since it is characterized by high reliability and reproducibility, providing also information regarding lens stiffness in aging dogs.

Shear wave elastography as a marker of anisotropy in denervated muscle tissue

Objectives

To assess the capability of shear wave elastography (SWE) to detect muscle denervation.

Methods

36 patients underwent electrodiagnostic studies (EDX) of the lower limbs and volunteered to undergo ultrasound examination of the Tibialis anterior (TA) and the Gastrocnemius medialis (GCM) muscles. A variable reflecting the level of anisotropy was created by calculating the difference between the longitudinal and transverse shear wave velocity (SWE-D).

Results

In the TA muscles, SWE-D correlated negatively with the quantity of fibrillation potentials (FP) and the degree of interference pattern (IP) reduction (p = 0.032, r = -0.185 and p = 0.006, r = -0.236, respectively). In the GCM muscles, SWE-D only correlated with the amount of IP reduction among patients of normal weight (p = 0.030, r = -0.285). There was also a significant difference in the overall SWE-D values in the GCM muscles between patients of normal weight and obese patients (p = 0.007).

Conclusions

Loss of anisotropy caused by denervation of muscle tissue may be measured quantitatively by calculating the differences between longitudinal and transverse shear wave velocities. However, obesity seems to hinder the SWE-based assessment of muscle denervation.

Significance

Being able to measure anisotropy caused by denervation acts as a base for further development of SWE methods to evaluate neurogenic injury.

Time-dependent changes in the stiffness of the neck extensor muscles with prolonged sitting and the effect of exercise

BackgroundNeck and shoulder exercises are recommended to improve Neck and Shoulder Pain (NSP). However, it is unclear why exercises for the neck and shoulder improve NSP, and methods for evaluating the effects of these exercises have not been clear.ObjectiveThe purpose of this study was to investigate time-dependent changes in stiffness of the neck extensor muscles due to prolonged sitting and the effect of exercise.MethodsTwenty-five healthy adult women sat with their hands on a desk for 90 min looking at a computer screen and then performed neck and shoulder exercise. Shear wave velocities (SWV) of the neck extensor muscles (the upper trapezius, levator scapulae, rhomboid major, and splenius capitis muscles) were measured at 0, 30, 60, and 90 min after the start of sitting and after the exercise. At the same time, changes in NSP were recorded.ResultsDuring prolonged sitting, SWV in the upper trapezius increased significantly with time (p < 0.001). Neck and shoulder exercise significantly decreased SWV and NSP (p < 0.001).ConclusionsThe results of this study revealed objective changes in neck muscle stiffness by prolonged sitting. Neck and shoulder exercise may reduce muscle stiffness and contribute to relieve NSP.

Relationship Between Muscle Tone and Elasticity: Simultaneous Quantitative Assessment Using Train-of-Four Monitoring and Continuous Shear Wave Elastography During Anesthesia Induction-A Prospective Observational Study

Background/Objectives: Non-invasive evaluations of muscle elasticity and tone are crucial in musculoskeletal medicine. Shear wave elastography (SWE) provides quantitative assessments of muscle elasticity, whereas train-of-four (TOF) monitoring measures muscle tone during neuromuscular blockades. This study investigated the relationship between muscle elasticity and tone during anesthesia induction using continuous SWE (C-SWE) and TOF monitoring. Methods: Fifteen patients who underwent general anesthesia with rocuronium were recruited. The muscle elasticity of the vastus lateralis was assessed using C-SWE, and muscle tone was evaluated using TOF monitoring. Measurements were taken at two time points: before rocuronium administration and during complete muscle relaxation, confirmed by the TOF ratio (TOF = 0). Statistical analyses were performed using paired t-tests and correlation analyses. Results: Data from 11 patients were analyzed. The mean shear wave velocity (SWV) decreased significantly from 5.0 ± 0.4 m/s before rocuronium administration to 3.1 ± 0.3 m/s during complete relaxation (p < 0.0001). A significant negative correlation was observed between the baseline SWV and the degree of reduction in the SWV (r = -0.728, p = 0.011). No significant correlations were found between SWV and demographic factors such as age, sex, height, or body mass index. Conclusions: C-SWE and TOF monitoring are reliable and sensitive methods for evaluating muscle elasticity and tone during general anesthesia. This study highlights the interplay between muscle tone and elasticity, suggesting that muscles with a higher baseline tone exhibit a greater reduction in elasticity after relaxation. These findings have implications for improving intraoperative muscle function assessments and advancing the application of C-SWE in clinical practice.

Identifying Heterogeneous Micromechanical Properties of Biological Tissues via Physics-Informed Neural Networks

The heterogeneous micromechanical properties of biological tissues have profound implications across diverse medical and engineering domains. However, identifying full-field heterogeneous elastic properties of soft materials using traditional engineering approaches is fundamentally challenging due to difficulties in estimating local stress fields. Recently, there has been a growing interest in data-driven models for learning full-field mechanical responses, such as displacement and strain, from experimental or synthetic data. However, research studies on inferring full-field elastic properties of materials, a more challenging problem, are scarce, particularly for large deformation, hyperelastic materials. Here, a physics-informed machine learning approach is proposed to identify the elasticity map in nonlinear, large deformation hyperelastic materials. This study reports the prediction accuracies and computational efficiency of physics-informed neural networks (PINNs) in inferring the heterogeneous elasticity maps across materials with structural complexity that closely resemble real tissue microstructure, such as brain, tricuspid valve, and breast cancer tissues. Further, the improved architecture is applied to three hyperelastic constitutive models: Neo-Hookean, Mooney Rivlin, and Gent. The improved network architecture consistently produces accurate estimations of heterogeneous elasticity maps, even when there is up to 10% noise present in the training data.

An Observational Study on the Prediction of Range of Motion in Soldiers Diagnosed with Patellar Tendinopathy Using Ultrasound Shear Wave Elastography

INTRODUCTION

This study hypothesized that changes in the elasticity of the quadriceps and patellar tendons before and after the diagnosis of patellar tendinopathy would correlate with the range of motion (ROM) following conservative treatment. We aimed to prospectively assess post-treatment ROM using multinomial logistic regression, incorporating elasticity measurements obtained via shear wave elastography (SWE).

MATERIALS AND METHODS

From March 2023 to April 2024, 95 patients (86 men; aged 20-45 years, mean 25.62 ± 5.49 years) underwent SWE preoperatively and two days post-diagnosis of patellar tendinopathy. Elasticity measurements of the rectus femoris, vastus medialis, vastus lateralis, patellar tendon, and biceps tendon were obtained during full flexion and extension. Based on ROM 56 days post-treatment, patients were categorized into two groups: Group A (ROM > 120 degrees) and Group B (ROM < 120 degrees). A multinomial logistic regression algorithm was employed to classify the groups using patient information and tendon elasticity measurements both at diagnosis and 1-week post-diagnosis.

RESULTS

The predictive accuracy using only patient information was 62%, while using only elasticity measurements yielded 68% accuracy. When combining patient information with elasticity measurements taken at diagnosis and two days post-diagnosis, the algorithm achieved an accuracy of 79%, sensitivity of 92%, and specificity of 56%.

CONCLUSIONS

The combination of patient information and tendon elasticity measurements obtained via SWE at pre-conservative treatment and early post-conservative treatment periods effectively predicts post-treatment ROM. This algorithm can guide rehabilitation strategies for soldiers with patellar tendinopathy.

Ultrasound Imaging Comparison of Crural Fascia Thickness and Muscle Stiffness in Stroke Patients with Spasticity

BACKGROUND/OBJECTIVE

Spasticity following stroke causes structural changes in the muscles and fascia, affecting the mobility and functional recovery of patients. Understanding these structural changes is critical to optimizing the rehabilitation strategies for patients. Therefore, in this study, we aimed to investigate the differences in crural and epimysial fascia thickness and muscle stiffness in the affected and unaffected lower limbs of chronic stroke patients with spasticity.

METHODS

A total of 88 patients with chronic stroke (mean age: 62.7 ± 10.2 years) were included in this study. Ankle range of motion, crural fascial thickness, and muscle stiffness in affected and unaffected lower limbs were assessed using ultrasound.

RESULTS

For the affected lower limbs, 59 patients (67.1%) exhibited a modified Ashworth scale score of 2, whereas 29 patients (32.9%) exhibited a score of 3. Ankle range of motion, fascia thickness, and muscle stiffness were also measured. The range of motion in ankle dorsiflexion and plantar flexion was significantly reduced on the affected side (p < 0.05). Crural fascia thickness was significantly greater in all regions of the affected side (anterior: 0.96 ± 0.14 vs. 0.72 ± 0.08 mm [p < 0.001]; lateral: 1.01 ± 0.14 vs. 0.75 ± 0.14 mm [p < 0.001]), and the epimysial fascia of the tibialis anterior muscle was similarly greater in the affected side (0.46 ± 0.07 vs. 0.34 ± 0.03 mm [p < 0.001]). However, no significant differences in muscle stiffness were observed between the affected and unaffected sides (p > 0.05).

CONCLUSIONS

Overall, these findings revealed significant fascial thickening with only minimal changes in muscle stiffness on the affected side, highlighting the importance of controlling fascial changes for post-stroke spasticity management.

Age and sex-related differences in elastic properties of the gastrocnemius muscle-tendon unit: an observational prospective study

Introduction

Changes in the mechanical properties of the gastrocnemius muscle-tendon unit can lead to abnormal biomechanics of lower limbs, which is a risk factor for the development of many diseases. However, fewer studies have explored physiological changes in the gastrocnemius muscle-tendon unit stiffness. This study aimed to investigate the age- and sex-related differences in the gastrocnemius muscle-tendon unit stiffness.

Methods

The study included 20 older women, 20 young women, and 20 older men. Shear wave elastography (SWE) was used to measure the stiffness of the medial gastrocnemius (MG), lateral gastrocnemius (LG), and Achilles tendon (AT) in all subjects in relaxed, neutral, and standing positions.

Results

The results showed no significant differences in the MG, LG, and AT stiffness between the dominant and non-dominant sides (p > 0.05). The MG, LG, and AT stiffness changed with positions (p < 0.05). The LG stiffness in older women was lower than in older men and young women in any position (p < 0.05). The MG stiffness in older men was greater than that in older women in any position, and age-related changes were found only in the relaxed and standing positions (p < 0.05). The AT stiffness was higher in older men only in the relaxed position (p < 0.05). There was no significant difference in AT stiffness between older and younger women at any position (p > 0.05).

Discussion

These results suggest that the bilateral gastrocnemius muscle-tendon unit stiffnesses were similar regardless of sex, age, and position. The stiffness of the gastrocnemius in women decreased with age. However, the effect of aging on AT stiffness was slight. Men have greater gastrocnemius stiffness in older adults.

Plantar Fascia Thickness and Stiffness in Healthy Individuals vs Patients With Plantar Fasciitis

BACKGROUND

Plantar fasciitis is a major cause of heel pain, resulting from repetitive trauma to the plantar fascia and leading to structural changes within the fascia. It has been observed that plantar fascia thickness in plantar fasciitis patients exceeds that of normal individuals. However, the biomechanical properties of the plantar fascia in patients with plantar fasciitis remain unclear. Therefore, this study aimed to compare plantar fascia stiffness between healthy individuals and patients with plantar fasciitis across different areas.

METHODS

Fifty-eight participants were divided into 2 groups: 29 healthy individuals and 29 individuals with plantar fasciitis. B-mode ultrasonography was used to assess plantar fascia thickness, whereas shear wave elastography was employed to measure plantar fascia stiffness. The study focused on 3 distinct areas: calcaneal insertion, 1-cm distal area, and 2-cm distal area. Additionally, the most painful area reported by patients was marked in the plantar fasciitis group.

RESULTS

The findings showed that the plantar fasciitis group exhibited significantly greater plantar fascia stiffness in almost all areas compared to the healthy group (P < .05). Moreover, the stiffness of the plantar fascia in the most painful area demonstrated the highest value compared with other areas within the plantar fasciitis group (P < .05).

CONCLUSION

This study suggests structural and mechanical changes in the plantar fascia in patients with plantar fasciitis.

Viability of shear wave elastography to predict mechanical/ultimate failure in the anterolateral and medial collateral ligaments of the knee

The purpose of this study was (1) to determine the utility of shear wave elastography as a predictor for the mechanical failure of superficial knee ligaments and (2) to determine the viability of shear wave elastography to assess injury risk potential. Our hypothesis was that shear wave elastography measurements of the anterolateral ligament and medial collateral ligament would directly correlate with the material properties and the mechanical failure of the ligament, serving as a prognostic measurement for injury risk. 8 cadaveric specimens were acquired, and tissue stiffness for the anterolateral ligament and medial collateral ligament were evaluated with shear wave elastography. The anterolateral ligament and medial collateral ligament were dissected and isolated for unilateral mechanical failure testing. Ultimate failure testing was performed at 100 % strain per second after 50 cycles of 3 % strain viscoelastic conditioning. Each specimen was assessed for load, displacement, and surface strain throughout failure testing. Rate of force, rate of strain development, and Young's modulus were calculated from these variables. Shear wave elastography stiffness for the anterolateral ligament correlated with mean longitudinal anterolateral ligament strain at failure (R2 = 0.853; P<0.05). Medial collateral ligament shear wave elastography calculated modulus was significantly greater than the anterolateral ligament shear wave elastography calculated modulus. Shear wave elastography currently offers limited reliability in the prediction of mechanical performance of superficial knee ligaments. The utility of shear wave elastography assessment for injury risk potential remains undetermined.

3D Ultrasound Shear Wave Elastography for Musculoskeletal Tissue Assessment Under Compressive Load: A Feasibility Study

Given its real-time capability to quantify mechanical tissue properties, ultrasound shear wave elastography holds significant promise in clinical musculoskeletal imaging. However, existing shear wave elastography methods fall short in enabling full-limb analysis of 3D anatomical structures under diverse loading conditions, and may introduce measurement bias due to sonographer-applied force on the transducer. These limitations pose numerous challenges, particularly for 3D computational biomechanical tissue modeling in areas like prosthetic socket design. In this feasibility study, a clinical linear ultrasound transducer system with integrated shear wave elastography capabilities was utilized to scan both a calibrated phantom and human limbs in a water tank imaging setup. By conducting 2D and 3D scans under varying compressive loads, this study demonstrates the feasibility of volumetric ultrasound shear wave elastography of human limbs. Our preliminary results showcase a potential method for evaluating 3D spatially varying tissue properties, offering future extensions to computational biomechanical modeling of tissue for various clinical scenarios.

Shear-Wave Elastography of the Achilles tendon: reliability analysis and impact of parameters modulating elasticity values

PURPOSE

Shear wave elastography (SWE) has seen many advancements in Achilles tendon evaluation in recent years, yet standardization of this technique is still problematic due to the lack of knowledge regarding the optimal way to perform the examination. The purpose of this study was to evaluate the effects of ankle position, probe frequency and physical effort on the shear modulus of the Achilles tendon, but also to determine the intra and inter-observer reliability of the technique.

METHODS

37 healthy volunteers were included; SWE protocol was performed by two examiners. We analyzed the shear modulus of the tendon with the ankle in neutral, maximum dorsiflexion and maximum plantar flexion using two different high frequency probes. Afterwards, the subjects performed a brief physical exercise and SWE measurements were repeated.

RESULTS

The L18-5 probe showed the highest ICC values (ICC = 0.798, 95% CI 0.660-0.880, p < 0.001) when positioned at 2 cm from the calcaneal insertion with the ankle in a neutral state. Conversely, utilizing the same L18-5 probe at 1 cm from the insertion during maximum plantar flexion of the ankle resulted in the lowest ICC (ICC = 0.422, 95% CI 0.032-0.655, p = 0.019). Significant variations in elasticity values were noted among different ankle positions and probe types, while no significant changes in elasticity were observed post-physical exercise.

CONCLUSION

Ankle position and probe frequency are factors that influence elasticity values of the Achilles tendon. An ankle position between 10 and 20 degrees of plantar flexion is the most suitable for SWE evaluation. However, more research focusing on Achilles tendon SWE is essential due to the challenges encountered in standardizing this region.

Using ultrasound elastography to assess non-invasive, non-pharmacological interventions for musculoskeletal stiffness: a systematic review and meta-analysis

PURPOSE

To evaluate the current evidence regarding the use of ultrasound elastography for assessing non-invasive, non-pharmacological interventions for eliciting changes in musculoskeletal stiffness.

METHODS

A systematic search of MEDLINE, CINAHL, EMBASE, and Web of Science databases was performed in accordance with Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines. Information on measurement and intervention procedures was extracted. Bias was assessed using Cochrane Risk of Bias or Risk of Bias In Non-randomised Studies of Interventions (ROBINS-I) tools for studies with true or quasi-experimental designs, respectively. Analyses were conducted for adequately powered subgroups based on intervention type, measurement site, and population assessed.

RESULTS

Twenty-one studies were included in the review. Overall risk of bias was low for true experimental studies and moderate for quasi-experimental studies. Subgroup analyses indicated a large overall effect for interventions involving manual physiotherapy and taping/splinting for reducing masseter muscle stiffness in patients with masticatory muscle disorders (g = 1.488, 95% CI = 0.320-2.655, p = 0.013). Analyses for other intervention types and patient groups were underpowered.

CONCLUSION

Ultrasound elastography demonstrates clinical applicability for assessing non-invasive, non-pharmacological interventions for musculoskeletal stiffness. However, the comparative efficacy of these interventions for modulating tissue stiffness remains inconclusive.

Effect of Knee Angle, Contractile Activity, and Intensity of Force Production on Vastus Lateralis Stiffness: A Supersonic Shear Wave Elastography Pilot Study

Supersonic shear image (SSI) ultrasound elastography provides a quantitative assessment of tissue stiffness using the velocity of shear waves. SSI's great potential has allowed researchers in fields like biomechanics and muscle physiology to study the function of complex muscle groups in different conditions. The aim of this study is to use SSI to investigate changes in the stiffness of the vastus lateralis (VL) muscle as a consequence of passive elongation, isometric contraction, and repeated muscle activity. In a single session, 15 volunteers performed a series of isometric, concentric, and eccentric contractions. SSI images were collected from the VL to assess its stiffness before and after the contractions and at various knee angles. Two-way within-subjects ANOVA was used to test the effects of muscle contraction type and knee angle on VL stiffness. Linear regression analysis was employed to assess the relationship between muscle stiffness and the intensity of isometric contractions. After maximal contractions, VL stiffness increased by approximately 10% compared to baseline values, and following maximal isometric (p < 0.01) and eccentric contractions (p < 0.05). Yet, there was no change in VL shear modulus at the end of concentric contractions. The relaxed VL shear modulus increased with knee flexion both before and after the knee extensor contractions (p < 0.001). A linear relationship between the shear modulus and the degree of isometric contraction was observed, although with notable individual variation (R2 = 0.125). Maximal contractile activity produces modest increases in relaxed muscle stiffness. The SSI-measured shear modulus increases linearly with the degree of isometric contraction.

Identifying heterogeneous micromechanical properties of biological tissues via physics-informed neural networks

The heterogeneous micromechanical properties of biological tissues have profound implications across diverse medical and engineering domains. However, identifying full-field heterogeneous elastic properties of soft materials using traditional engineering approaches is fundamentally challenging due to difficulties in estimating local stress fields. Recently, there has been a growing interest in using data-driven models to learn full-field mechanical responses such as displacement and strain from experimental or synthetic data. However, research studies on inferring full-field elastic properties of materials, a more challenging problem, are scarce, particularly for large deformation, hyperelastic materials. Here, we propose a physics-informed machine learning approach to identify the elasticity map in nonlinear, large deformation hyperelastic materials. We evaluate the prediction accuracies and computational efficiency of physics-informed neural networks (PINNs) by inferring the heterogeneous elasticity maps across three materials with structural complexity that closely resemble real tissue patterns, such as brain tissue and tricuspid valve tissue. We further applied our improved architecture to three additional examples of breast cancer tissue and extended our analysis to three hyperelastic constitutive models: Neo-Hookean, Mooney Rivlin, and Gent. Our selected network architecture consistently produced highly accurate estimations of heterogeneous elasticity maps, even when there was up to 10% noise present in the training data.

The Role of Ultrasound in the Diagnosis and Treatment of Meniscal Injuries

PURPOSE OF REVIEW

This review evaluates the current understanding of the role of ultrasound in the diagnosis and treatment of meniscal disorders.

RECENT FINDINGS

Ultrasound (US) demonstrates similar sensitivity and specificity when compared to magnetic resonance imaging in the evaluation of meniscal injuries when compared to arthroscopy. Meniscal extrusion (ME) under US can be a reliable metric to evaluate for meniscal root tears in knees with and without osteoarthritis (OA). Sonographic ME is associated with development of OA in knees without OA. US following allograft meniscal transplant may be useful in predicting graft failure. US findings can be used to screen for discoid menisci and may demonstrate snapping of a type 3 discoid lateral meniscus. Shear wave elastography for meniscal injuries is in its infancy; however, increased meniscal stiffness may be seen with meniscal degeneration. Perimeniscal corticosteroid injections may provide short term relief from meniscal symptoms, and intrameniscal platelet-rich plasma injections appear to be safe and effective up to three years. Ultrasound-assisted meniscal surgery may increase the safety of all inside repairs near the lateral root and may assist in assessing meniscal reduction following root repair. Diagnostic US can demonstrate with high accuracy a variety of meniscal pathologies and can be considered a screening tool. Newer technologies such as shear wave elastography may allow us to evaluate characteristics of meniscal tissue that is not possible on conventional imaging. US-guided (USG) treatment of meniscal injuries is possible and may be preferable to surgery for the initial treatment of degenerative meniscal lesions. USG or US-assisted meniscal surgery is in its infancy.

Shear Wave Ultrasonographic Elastography in Pediatric Spleens and Its Role in Differential Diagnosis

Shear wave elastography (SWE) has become popular in clinical practice for many diseases. However, there is not adequate research on spleen-related diseases. This study aimed to investigate the potential of quantitative values obtained through SWE in evaluating spleen pathologies in the pediatric population and to demonstrate its performance to differentiate splenomegaly-related diseases. The research group retrospectively included children with pathological diagnoses related to the spleen from November 2016 to April 2021, and they were categorized into three groups, including portal hypertension (PH), benign lymphoid hyperplasia (BLH), and malignant infiltration (MI). Spleen sizes and parenchymal stiffness were also calculated for each group. Subsequently, mean spleen stiffness in each group was compared with normal values within the same age group. In total, 2781 children (1379 children for the study group; 1402 children for the control group) were enrolled in the study. The highest stiffness was observed in the PH group, which is statistically higher than others (p < 0.05). Although the mean spleen stiffness in the group with BLH was higher than the control and MI group, the difference was not statistically significant (p = 0.08). The mean stiffness in the group with MI was significantly lower than both the control group (p = 0.005) and PH (p = 0.01). In conclusion, using SWE in the differential diagnosis of etiologies causing splenomegaly could make an important contribution.

Reliability of Ultrasound Shear Wave Elastography for Evaluating Psoas Major and Quadratus Lumborum Stiffness: Gender and Physical Activity Effects

OBJECTIVE

We aimed to assess the reliability of quantifying psoas major (PM) and quadratus lumborum (QL) stiffness with ultrasound shear wave elastography (SWE), and to explore the effects of gender and physical activity on muscle stiffness.

METHODS

Fifty-two healthy participants (18-32 y) were recruited. To determine reliability, 29 of them underwent repeated SWE measurements of PM and QL stiffness by an operator on the same day. The intra-class correlation coefficients (ICC3,1), standard error of measurement (SEM) and minimal detectable change with 95% confidence interval (MDC95) were calculated. The rest participants underwent a single measurement. Two-way MANCOVA was conducted for the effects of gender and physical activity on muscle stiffness.

RESULTS

The observed reliability for PM (ICC3,1 = 0.89-0.92) and QL (ICC3,1 = 0.79-0.82) were good-to-excellent and good, respectively. The SEM (kPa) was 0.79-1.03 and 1.23-1.28, and the MDC95 (kPa) was 2.20-2.85 and 3.41-3.56 for PM and QL, respectively. After BMI adjustment, both gender (PM: F = 10.15, p = 0.003; QL: F = 18.07, p < 0.001) and activity level (PM: F = 5.90, p = 0.005; QL: F = 6.33, p = 0.004) influenced muscle stiffness. The female and inactive groups exhibited higher stiffness in both muscles.

CONCLUSION

SWE is reliable for quantifying the stiffness of PM and QL. Female and physical inactivity may elevate PM and QL stiffness, underscoring the importance of accounting for these factors in muscle stiffness investigations. Larger prospective studies are needed to further elucidate their effects.

Diagnostic utility of shear wave elastography in musculoskeletal injuries: A narrative review

Shear wave elastography (SWE) is an emerging and promising ultrasound modality, and is more recently employed in the diagnosis of musculoskeletal (MSK) pathologies. SWE evaluates tissue stiffness by measuring the speed of propagating acoustic waves through body tissue structures. Knowing the variations in stiffness of MSK soft tissue can provide helpful diagnostic insight for the evaluation of pathology in muscles, tendons, ligaments, nerves, and other soft tissues. The goal of this review is to synthesize recent literature on the utility of SWE for MSK pathology diagnosis. This review reveals that SWE adds important diagnostic data for the evaluation of several pathologies, such as median mononeuropathy at the wrist, Achilles tendinopathy, and plantar fasciitis. The review also reveals a lack of evidence pertaining to appropriate standardization of use and the connection to reliable and valid diagnostic benefit in the clinical setting.

Explorative study using ultrasound time-harmonic elastography for stiffness-based quantification of skeletal muscle function

Time-harmonic elastography (THE) is an emerging ultrasound imaging technique that allows full-field mapping of the stiffness of deep biological tissues. THE's unique ability to rapidly capture stiffness in multiple tissues has never been applied for imaging skeletal muscle. Therefore, we addressed the lack of data on temporal changes in skeletal muscle stiffness while simultaneously covering stiffness of different muscles. Acquiring repeated THE scans every five seconds we quantified shear-wave speed (SWS) as a marker of stiffness of the long head (LHB) and short head (SHB) of biceps brachii and of the brachialis muscle (B) in ten healthy volunteers. SWS was continuously acquired during a 3-min isometric preloading phase, a 3-min loading phase with different weights (4, 8, and 12 kg), and a 9-min postloading phase. In addition, we analyzed temporal SWS standard deviation (SD) as a marker of muscle contraction regulation. Our results (median [min, max]) showed both SWS at preloading (LHB: 1.04 [0.94, 1.12] m/s, SHB: 0.86 [0.78, 0.94] m/s, B: 0.96 [0.87, 1.09] m/s, p < 0.001) and the increase in SWS with loading weight to be muscle-specific (LHB: 0.010 [0.002, 0.019] m/s/kg, SHB: 0.022 [0.017, 0.042] m/s/kg, B: 0.039 [0.019, 0.062] m/s/kg, p < 0.001). Additionally, SWS during loading increased continuously over time by 0.022 [0.004, 0.051] m/s/min (p < 0.01). Using an exponential decay model, we found an average relaxation time of 27 seconds during postloading. Analogously, SWS SD at preloading was also muscle-specific (LHB: 0.018 [0.011, 0.029] m/s, SHB: 0.021 [0.015, 0.027] m/s, B: 0.024 [0.018, 0.037] m/s, p < 0.05) and increased by 0.005 [0.003, 0.008] m/s/kg (p < 0.01) with loading. SWS SD did not change over loading time and decreased immediately in the postloading phase. Taken together, THE of skeletal muscle is a promising imaging technique for in vivo quantification of stiffness and stiffness changes in multiple muscle groups within seconds. Both the magnitude of stiffness changes and their temporal variation during isometric exercise may reflect the functional status of skeletal muscle and provide additional information to the morphological measures obtained by conventional imaging modalities.

Is muscle stiffness a determinant for range of motion in the leg muscles?

Previous training studies with comprehensive stretching durations have reported that an increase in range of motion (ROM) can be related to decreases in muscle stiffness. Therefore, the purpose of this study was to analyze the association between the passive muscle stiffness of three muscle groups (triceps surae, quadriceps, hamstrings) to the respective joint ROM. Thirty-six healthy male soccer players volunteered in this study. After a standardized warm-up, the muscle stiffness was tested via shear wave elastography in six muscles (gastrocnemius medialis and lateralis, rectus femoris, semitendinosus, semimembranosus, and biceps femoris long head). The hip extension, hip flexion, and ankle dorsiflexion ROM were also assessed with a modified Thomas test, a sit and reach test, and a standing wall push test, respectively. We found significant moderate to large correlations between hip flexion ROM and muscle stiffness for the semimembranosus (rP = -0.43; P = 0.01), biceps femoris long head (rP = -0.45; P = 0.01), and overall hamstring stiffness (rP = -0.50; P < 0.01). No significant correlations were found for triceps surae (rP = -0.12; P = 0.51 to 0.67) and rectus femoris muscle stiffness (rP = 0.25; P = 0.14) with ankle dorsiflexion and hip extension ROM, respectively. We conclude that muscle stiffness is an important contributor to hip flexion ROM, but less important for hip extension or ankle joint ROM. Additional contributors to ROM might be tendon stiffness or stretch/pain tolerance.

MRI T2 mapping and shear wave elastography for identifying main pain generator in delayed-onset muscle soreness: muscle or fascia?

INTRODUCTION

The main generator of delayed onset muscle soreness (DOMS) is still unknown. This study aimed to clarify the main generator of DOMS.

METHODS

Twelve participants performed eccentric exercise (EE) on lower legs. MRI and ultrasound were used to assess changes of calf muscle and deep fascia before and after EE. These results were then compared to the muscle pain level.

RESULTS

Compared to baseline, muscle pain peaked at 24-48 h after EE (downstairs 22.25 ± 6.196, 57.917 ± 9.298, F = 291.168, p < 0.01; resting 5.833 ± 1.899, 5.083 ± 2.429, F = 51.678, p < 0.01). Shear wave speed (SWE) of the deep fascia and T2 values of the gastrocnemius muscle and deep fascia all increased and peaked at 48 h after EE (1.960 ± 0.130, F = 22.293; 50.237 ± 2.963, F = 73.172; 66.328 ± 2.968, F = 231.719, respectively, p < 0.01). These measurements were positively correlated with DOMS (downstairs: r = 0.46, 0.76, 0.87, respectively, p < 0.001; resting: r = 0.42, 0.70, 0.77, respectively, p < 0.001). There was a significant positive correlation between SWE and T2 values of deep fascia (r = 0.54, p < 0.01).

CONCLUSION

DOMS is a common result of muscle and fascia injuries. Deep fascia edema and stiffness play a crucial role in DOMS, which can be effectively evaluated MR-T2 and SWE.

CRITICAL RELEVANCE STATEMENT

Delayed-onset muscle soreness is a common result of muscle and deep fascia injuries, in which the edema and stiffness of the deep fascia play a crucial role. Both MRI and shear wave elastography can be effectively used to evaluate soft tissue injuries.

KEY POINTS

• The deep fascia is the major pain generator of delayed-onset muscle soreness. • There is a significant correlation between fascia injury and delayed-onset muscle soreness. • MRI and shear wave elastography are preferred methods for assessing fascia injuries.

Chinese Ultrasound Doctors Association Guideline on Operational Standards for 2-D Shear Wave Elastography Examination of Musculoskeletal Tissues

The Ultrasound Physician Branch of the Chinese Medical Doctor Association sought to develop evidence-based recommendations on the operational standards for 2-D shear wave elastography examination of musculoskeletal tissues. A consensus panel of 22 Chinese musculoskeletal ultrasound experts reviewed current scientific evidence and proposed a set of 12 recommendations for 13 key issues, including instruments, operating methods, influencing factors and image interpretation. A final consensus was reached through discussion and voting. On the basis of research evidence and expert opinions, the strength of recommendation for each proposition was assessed using a visual analog scale, while further emphasizing the best available evidence during the question-and-answer session. These expert consensus guidelines encourage facilitation of the standardization of clinical practices for collecting and reporting shear wave elastography data.

Shear-wave elastography for the evaluation of tendinopathies: a systematic review and meta-analysis

PURPOSE

To compare pathologic and healthy tendons using shear-wave elastography (SWE).

METHODS

A systematic review with meta-analysis was done searching Pubmed and EMBASE up to September 2022. Prospective, retrospective and cross-sectional studies that used SWE in the assessment of pathologic tendons versus control were included. Our primary outcome were SWE velocity (m/s) and stiffness (kPa). Methodological quality was assessed by the methodological index for non-randomized studies (MINORS). We used the mean difference (MD) with corresponding 95% confidence intervals (CIs) to quantify effects between groups. We performed sensitivity analysis in case of high heterogeneity, after excluding poor quality studies according to MINORS assessment. We used Grades of Recommendation, Assessment, Development and Evaluation to evaluate the certainty of evidence (CoE).

RESULTS

Overall, 16 studies with 676 pathologic tendons (188 Achilles, 142 patellar, 96 supraspinatus, 250 mixed) and 723 control tendons (484 healthy; 239 contralateral tendon) were included. Five studies (31.3%) were judged as poor methodological quality. Shear-wave velocity and stiffness meta-analyses showed high heterogeneity. According to a sensitivity analysis, pathologic tendons had a lower shear wave velocity (MD of - 1.69 m/s; 95% CI 1.85; - 1.52; n = 274; I2 50%) compared to healthy tendons with very low CoE. Sensitivity analysis on stiffness still showed high heterogeneity.

CONCLUSION

Pathological tendons may have reduced SWE velocity compared to controls, but the evidence is very uncertain. Future robust high-quality longitudinal studies and clear technical indications on the use of this tool are needed.

PROTOCOL

PROSPERO identifier: CRD42023405410 CLINICAL RELEVANCE STATEMENT: SWE is a relatively recent modality that may increase sensitivity and diagnostic accuracy of conventional ultrasound imaging promoting early detection of tendinopathy. Non-negligible heterogeneity has been observed in included studies, so our findings may encourage the conduct of future high-quality longitudinal studies which can provide clear technical indications on the use of this promising tool in tendon imaging.

The Use of Shear-Wave Ultrasound Elastography in the Diagnosis and Monitoring of Musculoskeletal Injuries

Ultrasound elastography is a valuable method employed to evaluate tissue stiffness, with shear-wave elastography (SWE) recently gaining significance in various settings. This literature review aims to explore the potential of SWE as a diagnostic and monitoring tool for musculoskeletal injuries. In total, 15 studies were found and included in the review. The outcomes of these studies demonstrate the effectiveness of SWE in detecting stiffness changes in individuals diagnosed with Achilles tendinopathy, Achilles tendon rupture, rotator cuff rupture, tendinosis of the long head of the biceps tendon, injury of the supraspinatus muscle, medial tibial stress syndrome, and patellar tendinopathy. Moreover, SWE proves its efficacy in distinguishing variations in tissue stiffness before the commencement and after the completion of rehabilitation in cases of Achilles tendon rupture and patellar tendinopathy. In summary, the findings from this review suggest that SWE holds promise as a viable tool for diagnosing and monitoring specific musculoskeletal injuries. However, while the field of ultrasound elastography for assessing musculoskeletal injuries has made considerable progress, further research is imperative to corroborate these findings in the future.

Shear wave elastography correlates to degeneration and stiffness of the long head of the biceps tendon in patients undergoing tenodesis with arthroscopic shoulder surgery

BACKGROUND

Tendinopathy of the long head of the biceps (LHB) tendon causes degeneration and changes its stiffness. However, a reliable means of diagnosis has not been established. Shear wave elastography (SWE) provides quantitative tissue elasticity measurements. In this study, the relationship of preoperative SWE values with biomechanically measured stiffness and degeneration of the LHB tendon tissue was investigated.

METHODS

LHB tendons were obtained from 18 patients who underwent arthroscopic tenodesis. SWE values were measured preoperatively at 2 sites, proximal to and within the bicipital groove of the LHB tendon. The LHB tendons were detached immediately proximal to the fixed sites and at their superior labrum insertion. Tissue degeneration was histologically quantified using the modified Bonar score. Tendon stiffness was determined using a tensile testing machine.

RESULTS

The SWE values of the LHB tendon were 502.1 ± 113.6 kPa proximal to the groove and 439.4 ± 123.3 kPa within the groove. The stiffness was 39.3 ± 19.2 N/mm. The SWE values displayed a moderate positive correlation with the stiffness proximal to the groove (r = 0.80) and within it (r = 0.72). The SWE value of the LHB tendon within the groove showed a moderate negative correlation with the modified Bonar score (r = -0.74).

CONCLUSIONS

These findings suggest that preoperative SWE values of the LHB tendon correlate moderately positively with stiffness and moderately negatively with tissue degeneration. Therefore, SWE may predict LHB tendon tissue degeneration and changes in stiffness caused by tendinopathy.

Reliability of lower leg muscle elasticity using shear wave elastography in non-weight-bearing and weight-bearing

PURPOSE

Muscle elasticity can be quantified with shear wave elastography (SWE) and has been used as an estimate of muscle force but reliability has not been established for lower leg muscles. The purpose of this study was to examine the intra-rater and inter-rater reliability of elasticity measures in non-weight-bearing (NWB) and weight-bearing (WB) for the tibialis anterior (TA), tibialis posterior (TP), peroneal longus (PL), and peroneal brevis (PB) muscles using SWE.

METHODS

A total of 109 recreationally active healthy adults participated. The study employed a single-cohort, same-day repeated-measures test-retest design. Elasticity, measured in kilopascals as the Young's modulus, was converted to the shear modulus. All four muscles were measured in NWB and at 90% WB.

RESULTS

Intra-rater reliability estimates were good to excellent for NWB (ICC = 0.930-0.988) and WB (ICC = 0.877-0.978) measures. Inter-rater reliability estimates were moderate to good (ICC = 0.500-0.795) for NWB measures and poor to good (ICC = 0.346-0.910) for WB measures.

CONCLUSION

Despite the studies poor to good inter-rater variability, the intra-rater reproducibility represents the potential benefit of SWE in NWB and WB. Establishing the reliability of SWE with clinical and biomechanical approaches may aid in improved understanding of the mechanical properties of muscle.

Acoustic radiation force impulse shear wave elastography quantifies upper limb muscle in patients with Duchenne muscular dystrophy

We investigated whether the upper limb muscle stiffness quantified by the acoustic radiation force impulse shear wave elastography (ARFI/SWE) is a potential biomarker for age-related muscle alteration and functional decline in patients with Duchenne muscular dystrophy (DMD). 37 patients with DMD and 30 typically developing controls (TDC) were grouped by age (3-8, 9-11, and 12-18 years). ARFI/SWE measured the biceps and deltoid muscle's shear wave velocities (SWVs). Performance of Upper Limb Module (PUL 1.2 module) assessed muscle function in DMD patients. Mann Whitney test compared muscle SWVs between DMD and TDC, stratified by three age groups. We used analysis of variance with Bonferroni correction to compare muscle SWVs between DMD and TDC and correlated muscle SWVs with PUL results in the DMD group. Results showed that the SWVs of biceps differentiated DMD patients from TDC across age groups. Younger DMD patients (3-8 years) exhibited higher SWVs (p = 0.013), but older DMD patients (12-18 years) showed lower SWVS (p = 0.028) than same-aged TDC. DMD patients had decreasing biceps SWVs with age (p < 0.001), with no such age effect in TDC. The SWVs of deltoid and biceps positively correlated with PUL scores (r = 0.527 ∼ 0.897, P < 0.05) and negatively correlated with PUL timed measures (r = -0.425 ∼ -0.542, P < 0.05) in DMD patients. Our findings suggest that ARFI/SWE quantifying the SWVs in upper limb muscle could be a potential biomarker to differentiate DMD from TDC across ages and that DMD patients showed age-related muscle alteration and limb functional decline.

The Role of Superb Microvascular Imaging and Shear Wave Elastography in the Prediction of Hemorrhage Complications After Renal Parenchyma Biopsy

OBJECTIVES

The aim of study was to evaluate the diagnostic utility of the renal parenchyma elasticity with the shear wave elastography (SWE) and microvascularization with the superb microvascular imaging (SMI) technique before kidney biopsy and to predict the complication of hemorrhage before kidney biopsy.

METHODS

A total of 75 patients were included in the prospective study. Before the biopsy, vascularity features of the kidney parenchyma in the area to be biopsied were assessed by SMI and parenchymal stiffness by SWE and were examined by 2 independent radiologists.

RESULTS

A statistically significant difference was found in the SMI and SWE values between the groups with and without hematoma and hematuria when compared with the Student t test and Mann-Whitney U test ( P < 0.05). The SWE hardness cutoff value, which maximizes the prediction of the development of hematuria, was found to be 18.40 kPa, and the sensitivity and specificity values were 84.4% and 62.8%, respectively. In SMI vascularity index values, the cutoff value was found to be 0.247410800 kPa, and sensitivity and specificity values were 81.3% and 83.7%, respectively. The cutoff value of the SMI vascularity index values that maximized the prediction of hematoma development was 0.297009650, and the sensitivity and specificity values were 87% and 87%, respectively.

CONCLUSIONS

We believe that evaluating and standardizing the microvascularization and elasticity of the kidney parenchyma before a percutaneous kidney biopsy will be potentially useful as a guiding method in the prediction of postbiopsy hemorrhage development.

Effects of muscle fatigue on exercise-induced hamstring muscle damage: a three-armed randomized controlled trial

PURPOSE

Hamstring injuries in soccer reportedly increase towards the end of the matches' halves as well as with increased match frequency in combination with short rest periods, possibly due to acute or residual fatigue. Therefore, this study aimed to investigate the effects of acute and residual muscle fatigue on exercise-induced hamstring muscle damage.

METHODS

A three-armed randomized-controlled trial, including 24 resistance-trained males, was performed allocating subjects to either a training group with acute muscle fatigue + eccentric exercise (AF/ECC); residual muscle fatigue + eccentric exercise (RF/ECC) or a control group with only eccentric exercise (ECC). Muscle stiffness, thickness, contractility, peak torque, range of motion, pain perception, and creatine kinase were assessed as muscle damage markers pre, post, 1 h post, and on the consecutive three days.

RESULTS

Significant group × time interactions were revealed for muscle thickness (p = 0.02) and muscle contractility parameters radial displacement (Dm) and contraction velocity (Vc) (both p = 0.01), with larger changes in the ECC group (partial η2 = 0.4). Peak torque dropped by an average of 22% in all groups; stiffness only changed in the RF/ECC group (p = 0.04). Muscle work during the damage protocol was lower for AF/ECC than for ECC and RF/ECC (p = 0.005).

CONCLUSION

Hamstring muscle damage was comparable between the three groups. However, the AF/ECC group resulted in the same amount of muscle damage while accumulating significantly less muscle work during the protocol of the damage exercise.

TRIAL REGISTRATION

This study was preregistered in the international trial registration platform (WHO; registration number: DRKS00025243).

High-Resolution Imaging Insights into Shoulder Joint Pain: A Comprehensive Review of Ultrasound and Magnetic Resonance Imaging (MRI)

Shoulder joint pain is a complex and prevalent clinical concern affecting individuals across various ages and lifestyles. This review delves into the pivotal role of high-resolution imaging techniques, namely ultrasound and magnetic resonance imaging (MRI), in the comprehensive assessment and management of shoulder joint pain. We explore the anatomical foundations of the shoulder, common etiologies of pain, and the significance of precise diagnosis. High-resolution imaging facilitates the identification of various shoulder pathologies and is crucial in treatment planning, surgical interventions, and long-term prognosis assessment. We examine emerging technologies, discuss challenges and limitations, and chart potential future developments, emphasizing the ongoing evolution of imaging in this critical healthcare domain. In conclusion, high-resolution imaging is an indispensable tool, continually advancing to meet the diagnostic and therapeutic needs of individuals grappling with shoulder joint pain.

Musculoskeletal Ultrasound for the Diagnosis of Plantar Fasciitis: An Accuracy and Diagnostic Yield Study

Objective

To evaluate the accuracy of musculoskeletal ultrasound measurement of plantar fascia thickness and shear wave elastography (SWE) calculation of Young's modulus in the diagnosis of plantar fasciitis (PFis), and to explore whether it will have any impact on clinical decision-making, rather than just using established diagnostic methods of clinical symptoms and signs.

Methods

A diagnostic single-center study was conducted in 60 patients with PFis and 64 patients with other types of heel pain. The sensitivity and specificity of musculoskeletal ultrasound in the diagnosis of PFis were calculated according to the diagnostic criteria for PFis recommended by the Clinical Practice Guide for PFis of the American Physical Therapy Association (APTA) Orthopaedic Branch. The analysis of the receiver operating characteristic curve of the subjects was used to study the accuracy of the diagnosis of PFis by two indicators alone and two indicators jointly.

Results

The thickness of plantar fascia measured by musculoskeletal ultrasound and the area under the curve (AUCs) calculated by shear wave elastography for diagnosing PFis were 0.925 and 0.917, respectively, and the optimal cutoff values were 3.15 mm (sensitivity: 100.0%, specificity: 81.3%) and 63.24 kPa (sensitivity: 78.3%, specificity: 92.2%), respectively. The area under the curve (AUCs) for the combined diagnosis of the two is 0.973 (sensitivity: 93.3%, specificity: 93.8%).

Conclusion

The thickness of plantar fascia measured by musculoskeletal ultrasound and Young's modulus calculated by SWE have high accuracy in diagnosing PFis, and the combined diagnosis of the two can improve the diagnostic accuracy of patients with PFis.

A scoping review of current and emerging techniques for evaluation of peripheral nerve health, degeneration and regeneration: part 2, non-invasive imaging

Peripheral neuroregenerative research and therapeutic options are expanding exponentially. With this expansion comes an increasing need to reliably evaluate and quantify nerve health. Valid and responsive measures of the nerve status are essential for both clinical and research purposes for diagnosis, longitudinal follow-up, and monitoring the impact of any intervention. Furthermore, novel biomarkers can elucidate regenerative mechanisms and open new avenues for research. Without such measures, clinical decision-making is impaired, and research becomes more costly, time-consuming, and sometimes infeasible. Part 1 of this two-part scoping review focused on neurophysiology. In part 2, we identify and critically examine many current and emerging non-invasive imaging techniques that have the potential to evaluate peripheral nerve health, particularly from the perspective of regenerative therapies and research.

Measuring Shear Wave Velocity in Adult Skeletal Muscle with Ultrasound 2-D Shear Wave Elastography: A Scoping Review

Ultrasound 2-D shear wave elastography (US 2D-SWE) is a non-invasive, cost-effective tool for quantifying tissue stiffness. Amidst growing interest in US 2D-SWE for musculoskeletal research, it has been recommended that shear wave velocity (SWV) should be reported instead of elastic moduli to avoid introducing unwanted error into the data. This scoping review examined the evolving use of US 2D-SWE to measure SWV in skeletal muscle and identified strengths and weaknesses to guide future research. We searched electronic databases and key review reference lists to identify articles published between January 2000 and May 2021. Two reviewers assessed the eligibility of records during title/abstract and full-text screening, and one reviewer extracted and coded the data. Sixty-six studies met the eligibility criteria, of which 58 were published in 2017 or later. We found a striking lack of consensus regarding the effects of age and sex on skeletal muscle SWV, and widely variable reliability values. Substantial differences in methodology between studies suggest a pressing need for developing standardized, validated scanning protocols. This scoping review illustrates the breadth of application for US 2D-SWE in musculoskeletal research, and the data synthesis exposed several notable inconsistencies and gaps in current literature that warrant consideration in future studies.

Shear-wave elastography of the plantar fascia: a systematic review and meta-analysis

PURPOSE

To assess the efficacy of shear-wave elastography (SWE) of the plantar fascia (PF) in identifying plantar fasciitis.

METHODS

A literature search was conducted on the PubMed and Medline databases for articles published up to August 2022. The Newcastle-Ottawa scale was used to assess the risk of bias. We included original research studies in English dealing with the evaluation of patients with plantar fasciitis by means of SWE and including shear modulus (KPa) and/or shear-wave velocity (m/s). We compared healthy and pathologic PF stiffness using the standardised mean difference (SMD) in a random-effects model (95% CI).

RESULTS

Five studies were included with a total of 158 pathologic PFs and 134 healthy PFs. No significant publication bias was detected. Studies were highly heterogeneous (p < 0.00001; I² = 97%). Pathologic PFs showed significantly lower stiffness, with an SMD of - 3.00 m/s (95% confidence interval: - 4.95 to - 1.06, p = 0.002), compared to healthy PF.

CONCLUSION

Pathologic PFs present significantly lower stiffness than healthy PFs. However, the analysed studies are highly heterogeneous.

Effect of plantar fascia-specific stretching and Achilles tendon stretching on shear wave elasticity of the plantar fascia in healthy subjects

BACKGROUND

The effect of stretching on the mechanical properties of the plantar fascia (PF) remain unclear. This study was performed to determine the effect of PF-specific stretching (PFSS) and Achilles tendon stretching (ATS) on the viscoelastic properties of the PF with shear wave elastography (SWE).

METHODS

We recruited 14 participants (8 men, 6 women) with no history of PF disorders or painful episodes. The mean age of the participants was 30.9 ± 4.8 (range, 25-41) years. All participants performed sustained PFSS (sPFSS) on one foot and intermittent PFSS (iPFSS) on the other foot. Two weeks later, all participants performed sustained ATS (sATS) on one foot and intermittent ATS (iATS) on the other foot. SWE measurements were performed immediately after each stretching.

RESULTS

The PF elasticity immediately before stretching ranged from 133.8 kPa to 144.7 kPa. The PF elasticity after stretching ranged from 158.9 kPa to 215.8 kPa. There was a significant increase in PF elasticity after sPFSS, iPFSS, sATS, and iATS (P < .01). The elasticity after sATS was greater than that after iATS (P = .03). In contrast, there were no differences in PF elasticity after stretching between sPFSS and iPFSS (P = .13), sPFSS and sATS (P = .17), or iPFSS and iATS (P = .50).

CONCLUSIONS

PF elasticity increased after stretching regardless of the frequency and type of PFSS and ATS.

LEVEL OF EVIDENCE

Level II, prospective cohort study.

A New Estimation Scheme for Improving the Performance of Shear Wave Elasticity Imaging

Shear wave velocity (SWV) reconstruction based on time-of-flight (TOF) is widely adopted to realize shear wave elasticity imaging (SWEI). It typically breaks down the reconstruction of a SWV image into many kernels and treats them independently. We hypothesized that information exchange among kernels improves the performance of SWEI. Therefore, we propose the approach of iterative re-weighted least squares based on inter-kernel communication (IKC-IRLS). We also hypothesized that time-to-peak (TTP) is superior to cross-correlation (CC) in visualizing small targets because TTP uses higher shear wave frequencies than CC. To examine the hypotheses, IKC-IRLS was combined with TTP data and compared with four established methods. The five methods were tested by imaging several small-size stiff targets (2.5, 4.0 and 6.4 mm in diameter) using different kernel sizes in the simulation and real experiments. The results indicate that the IKC-IRLS approach can mitigate speckle noise and is robust to TTP outliers. Consequently, the proposed method achieves the highest contrast-to-noise ratio and the lowest mean absolute percentage error of target in almost all tested cases.

Two-dimensional shear wave elastography: a new tool for evaluating respiratory muscle stiffness in chronic obstructive pulmonary disease patients

BACKGROUND

Impaired respiratory function caused by respiratory muscle dysfunction is one of the common consequences of chronic obstructive pulmonary disease (COPD). In this study, two-dimensional shear wave elastography (2D-SWE) was used to measure diaphragm stiffness (DS) and intercostal muscle stiffness (IMS) in patients with COPD; in addition, the value of 2D-SWE in evaluating respiratory function was determined.

METHODS

In total, 219 consecutive patients with COPD and 20 healthy adults were included. 2D-SWE was used to measure the DS and IMS, and lung function was also measured. The correlation between respiratory muscle stiffness and lung function and the differences in respiratory muscle stiffness in COPD patients with different severities were analysed.

RESULTS

2D-SWE measurements of the DS and IMS presented with high repeatability and consistency, with ICCs of 0.756 and 0.876, respectively, and average differences between physicians of 0.10 ± 1.61 and 0.07 ± 1.65, respectively. In patients with COPD, the DS and IMS increased with disease severity (F₁ = 224.50, F₂ = 84.63, P < 0.001). In patients with COPD, the correlation with the forced expiratory volume in one second (FEV₁)/forced vital capacity (FVC), predicted FEV₁% value, residual volume (RV), total lung capacity (TLC), RV/TLC, functional residual capacity (FRC) and inspiratory capacity (IC) of DS (r₁=-0.81, r₂=-0.63, r₃ = 0.65, r₄ = 0.54, r₅ = 0.60, r₆ = 0.72 and r₇=-0.41, respectively; P < 0.001) was stronger than that of IMS (r₁=-0.76, r₂=-0.57, r₃ = 0.57, r₄ = 0.47, r₅ = 0.48, r₆ = 0.60 and r₇=-0.33, respectively; P < 0.001).

CONCLUSION

2D-SWE has potential for use in evaluating DS and IMS. A specific correlation was observed between respiratory muscle stiffness and lung function. With the worsening of the severity of COPD and the progression of lung function impairment, the DS and IMS gradually increased.

The Role of Ultrasound in the Evaluation of Elbow Medial Ulnar Collateral Ligament Injuries in Throwing Athletes

PURPOSE OF REVIEW

Although ultrasound (US) imaging is commonly used to evaluate the elbow medial ulnar collateral ligament (mUCL) in throwing athletes, significant technical heterogeneity exists in the published literature and in practice. This has resulted in variable and often ambiguous US diagnostic criteria for mUCL injury. This review summarizes the literature on sonographic evaluation of the mUCL and outlines recommendations for consistent descriptive terminology, as well as future clinical and research applications.

RECENT FINDINGS

Both acute and chronic throwing loads in overhead athletes cause the mUCL to become thicker and more lax on stress testing, and these changes tend to revert after a period of prolonged rest. Stress US (SUS) can aid in the diagnosis of mUCL tears and may help identify athletes at risk of mUCL injury. Variability exists in terminology, elbow flexion angle, amount of stress applied, and technique of stress testing. Recent studies have suggested an injured elbow stress delta (SD-change in ulnohumeral joint (UHJ) space with valgus stress) of 2.4 mm and a stress delta difference (SDD-side-side difference in SD) of 1 mm each denote abnormal UHJ laxity due to mUCL injury. US imaging is a powerful and widely accessible tool in the evaluation elbow mUCL injuries. Sonologists should consider how their US techniques compare with published methods and use caution when applying diagnostic criteria outside of those circumstances. Currently, an SD of 2.4 mm and an SDD of 1 mm provide the best diagnostic accuracy for mUCL tears requiring surgery. Finally, preliminary work suggests that shear wave elastography may be helpful in evaluating the biomechanical properties of the mUCL, but additional research is needed.

Shear wave elastography combined with electromyography to assess the effect of botulinum toxin on spastic dystonia following stroke: A pilot study

Background

Shear wave elastography (SWE) is a method for carrying out a quantitative assessment of the mechanical properties of soft tissues in terms of stiffness. In stroke survivors, the paretic muscles may develop hypertonia due to both neural-mediated mechanisms and structural alterations with consequent muscular fibrous-fatty remodeling.

Methods

Fourteen adult patients with spastic dystonia following stroke were recruited. Muscle hypertonia was assessed using the modified Ashworth scale (MAS). Muscle activation was measured by surface electromyography (sEMG) with the selected muscle in shortened (spastic dystonia) and stretched (dynamic stretch reflex) positions. SWE was performed on a selected paretic muscle and on the contralateral non-paretic one to calculate shear wave velocities (SWV) along and across muscular fibers. The modified Heckmatt scale (MHS) pattern was also determined. All evaluations were performed shortly before BoNT-A injections (T0) and one month later (T1).

Results

All SWV on paretic muscles were higher than contralateral non-paretic ones (p < 0.01). After BoNT-A injection, a significant reduction in MAS (p = 0.0018), spastic dystonia (p = 0.0043), and longitudinal SWE measurements, both in shortened (p = 0.001) and in stretched muscular conditions (p = 0.0029), was observed. No significant changes in SWV on non-paretic muscles were observed. Higher SWV resulted along the direction of muscular fibers vs. across them (p = 0.001). No changes resulted from the MHS evaluations after BoNT-A. There was a positive correlation between MHS scores and SWV values while the muscle was in the shortened position, but not with spastic dystonia recorded by sEMG.

Conclusions

This is the first study evaluating the effect of BoNT-A on muscle hypertonia following stroke, assessed by both SWE and sEMG. These findings support SWE as a useful method to disclose intrinsic muscular remodeling, independently of the effect of spastic dystonia, in particular, while muscles were assessed in a neutral position. SWE measurements of muscle stiffness cannot tell apart neural-mediated and intrinsic muscle hypertonia. Interestingly, when sEMG activity is very limited, as in spastic muscles kept in a shortened position, SWE can provide a measurement of stiffness due almost completely to intrinsic muscle changes. Alongside sEMG, SWE could aid clinicians in the assessment of responses to treatments.

2D-SWE of the Metacarpophalangeal Joint Capsule in Horses

(1) Two-dimensional shear wave elastography (2D-SWE) employs an ultrasound impulse to produce transversely oriented shear waves, which travel through the surrounding tissue according to the stiffness of the tissue itself. The study aimed to assess the reliability of 2D-SWE for evaluating the elastosonographic appearance of the distal attachment of the fetlock joint capsule (DJC) in sound horses and in horses with osteoarthritis (OA) (2). According to a thorough evaluation of metacarpophalangeal joint (MCPJ), adult horses were divided in a sound Group (H) and in OA Group (P). Thereafter, a 2D-SWE of MCPJs was performed. Shear wave velocity (m/sec) and Young’s modulus (kPa) were calculated independently by two operators at each selected ROI. Statistical analysis was performed with R software. (3) Results: 2D-SWE had good–excellent inter-CC and intra-CC in both groups. Differences in m/s and kPa between Groups H and P were found in transverse scans with lower values in Group P. No correlation with age or DJC thickness was found. (4) Conclusions: 2D-SWE was repeatable and reproducible. In Group H, DJC was statistically stiffer than in Group P only in transverse scan. The technique showed poor sensitivity and specificity in differentiating fetlocks affected by OA.

Shear-Wave Elastography and Viscosity PLUS for the Assessment of Peripheric Muscles in Healthy Subjects: A Pre- and Post-Contraction Study

Viscosity is a novel parameter, recently introduced in the use of elastographic techniques, correlating to shear-wave dispersion. The purpose of this study was to provide normal reference viscosity values for the peripheral muscles in healthy volunteers. This prospective study included 38 subjects who underwent US examinations between November 2021 and January 2022. Measurements were taken on the calf and the deltoid muscles in both pre- and post-contraction states. The age range was 21–29 years, with a median of 26 years. The SWE and ViPLUS values in the deltoid muscles were significantly higher than in the soleus muscles in both pre- and post-contraction sets (p = 0.002). There were statistically significant differences between the pre- and post-contraction values for both the SWE and ViPLUS values in the subgroup analysis. The ICC estimates and the 95% confidence intervals were based on a mean rating (k = 2), an absolute agreement, and a two-way random-effects model, demonstrating excellent agreement between the measurements taken by the two examiners.

Intestinal Elastography in the Diagnostics of Ulcerative Colitis: A Narrative Review

Ulcerative colitis (UC) is an inflammatory bowel disease (IBD) that mainly affects developed countries, but the number of cases in developing countries is increasing. We conducted a narrative review on the potential application of ultrasound elastography in the diagnosis and monitoring of UC, as this newly emerging method has promising results in other gut diseases. This review fulfilled the PRISMA Statement criteria with a time cut-off of June 2022. At the end of the review, of the 1334 identified studies, only five fulfilled all the inclusion criteria. Due to the small number of studies in this field, a reliable assessment of the usefulness of ultrasound elastography is difficult. We can only conclude that the transabdominal elastography examination did not significantly differ from the standard gastrointestinal ultrasonography examination and that measurements of the frontal intestinal wall should be made in the longitudinal section. The reports suggest that it is impossible to estimate the clinical scales used in disease assessment solely on the basis of elastographic measurements. Due to the different inclusion criteria, measurement methodologies, and elastographic techniques used in the analysed studies, a reliable comparative evaluation was impossible. Further work is required to assess the validity of expanding gastrointestinal ultrasonography with elastography in the diagnosis and monitoring of UC.