Reliable protocol for shear wave elastography of lower limb muscles at rest and during passive stretching

Ex vivo mechanical properties of human thoracolumbar fascia and erector spinae aponeurosis under traction loading and shear wave elastography

The thoracolumbar fascia (TLF) and the erector spinae aponeurosis (ESA) play an important role in the biomechanics of the spine and could be a source of low back pain. Although the TLF and ESA are key structures in several musculoskeletal dysfunctions and in tissue engineering, there is still a lack of evidence in the literature to prove that they have different mechanical properties and roles when considered as a single tissue. Furthermore, no methods are currently available to study these structures in vivo. The objective of this study was to analyze the ex-vivo tensile properties TLF and ESA, and to test the potential of ultrasound shearwave elastography (SWE) to characterize these tissues. Hundred samples from N = 10 fresh-frozen human donors were studied. Shear wave speed (SWS) was measured in all samples with SWE, and their tensile properties were measured with mechanical testing. Results show that TLF is anisotropic, and more compliant than ESA. SWS was not significantly correlated to tensile moduli. These findings could potentially aid surgeons in their daily practices, assist engineers with in silico simulations, and support physiotherapists in musculoskeletal rehabilitation by enabling them to customize medical interventions for each specific patient and clinical condition. However, further research is necessary to further investigate the behavior in terms of time-dependent response and link between the tissue anisotropy and microstructural organization.

Upper and lower limb muscle stiffness in children with cerebral palsy compared to typically developing children: Insights from shear wave elastography

Children with spastic cerebral palsy (CP) experience altered muscle tone due to biomechanical changes, traditionally assessed through clinical scales. Shear wave elastography (SWE) offers a non-invasive way to quantify these changes. This study aimed to compare SWE measurements in spastic CP and typically developing (TD) children and investigate influencing factors such as joint position, range of motion, demographics, physical condition and, in CP children, the characteristics of CP. It also examined correlations between SWE measurements and spasticity scales in CP children. SWE measured the elastic modulus (kPa) of biceps brachii (BB), pronator teres (PT), adductor longus (AL), lateral gastrocnemius (LG), and soleus (SOL) muscles at rest and during maximum passive stretching (MPS) in 34 spastic CP children (age: 3-17) and 44 TD children (age: 3-14). Significant differences (p < 0.05) in SWE were found between CP and TD children. CP children had lower values in upper limb muscles and higher values in lower limb muscles at rest, with the opposite pattern during MPS. The Ashworth and Tardieu scales were associated with the elastic modulus in lower limb muscles (AL, GL, and SOL) at rest in CP children. Differences in elastic modulus at rest and MPS between upper and lower limbs and in spastic CP and TD children showed no consistent links to spasticity scales, reflecting neurological dysregulation, muscle architecture, and joint structure involvement. These variations were linked to neurological dysregulation and muscle architecture, with joint structures also affecting. SWE may offer a more precise assessment of muscle spasticity, minimizing the impact of confounding joint structures.

Feasibility of shear wave elastography to assess upper limb spasticity in patients after brain injury

PURPOSE

To assess the feasibility of Shear Wave Elastography (SWE) for quantifying upper limb spasticity in people after brain injury.

METHODS

This observational study included 52 patients with upper limb spasticity after brain injury. Participants underwent a two-week rehabilitation treatment. The modified Ashworth scale (MAS), upper extremity section of the Fugl-Meyer motor scale (FMMS-UE), Barthel index (BI) and SWE were assessed before and after a two-week rehabilitation. The shear modulus was used to evaluate the stiffness of the biceps brachii at the transverse and longitudinal plane of 0°and 90°elbow flexion.

RESULTS

In our study, paretic side shear modulus values were significantly larger than non-paretic sides (all p-values < 0.05), with significant reductions only on the paretic side (all p-values < 0.001) after 2-week rehabilitation treatment. At baseline, MAS and shear modulus had a significant positive correlation. After rehabilitation, only the longitudinal plane shear modulus showed a correlation with MAS. No significant correlations were found between shear modulus and FMMS-UE or BI scores, except for a negative correlation between shear modulus and BI at 0° transverse plane flexion.

CONCLUSIONS

Our findings indicate that SWE effectively quantifies upper limb spasticity and can assess the impact of rehabilitation treatment.

Shear wave elastography in the assessment of gastrocnemius spastic muscle elasticity: influences of ankle position and muscle contraction

BACKGROUND

Following upper motor neuron syndromes (UMNS), intrinsic viscoelastic muscle properties such as elastic stiffness may be altered, which leads to muscle hyper-resistance to passive mobilization. So far, no gold standard assessment of hyper-resistance, whether clinical or instrumental, is available. Shear wave elastography (SWE) has been increasingly used for non-invasive evaluation of elastic stiffness of skeletal muscles in people with hyper-resistance.

AIM

Our study aimed to evaluate the validity of SWE at ankle neutral resting position (ANRP). Additional objectives included assessing the influence of ankle position, muscle contraction, and laterality on elastic stiffness, and evaluating the reproducibility and responsiveness of SWE.

DESIGN

Observational cohort study.

SETTING

Outpatients of the physical and rehabilitation medicine department of a university hospital in Brussels.

POPULATION

Thirty hemiparetic patients following UMNS with hyper-resistance in gastrocnemii muscles.

METHODS

Elastic stiffness was quantified by shear wave velocity (SWV) measurements of gastrocnemii muscles. A higher SWV corresponds to a higher elastic stiffness. Measurements were performed on the affected and less-affected limbs in ANRP, in passive dorsiflexion and during isometric contraction. Assessments were performed 3 times. Criterion validity, reproducibility, and responsiveness were evaluated. A linear mixed model was used to study position and laterality effect.

RESULTS

In ANRP, reproducibility was excellent and SWV was significantly higher in the affected limb than in the less-affected limb. This laterality effect disappeared in passive dorsiflexion and was even reversed during isometric contraction. SWV was significantly higher on both sides in passive dorsiflexion and during contraction than in ANRP.

CONCLUSIONS

Our results suggest that SWE measurements in ANRP are reliable and may provide a more valid measurement of gastrocnemii elastic stiffness following UMNS.

CLINICAL REHABILITATION IMPACT

SWE may be a useful clinical tool as an extension of the physical exam for longitudinal monitoring of passive muscle elastic stiffness, to assist with treatment decisions and to better quantify the therapeutic effect of procedures to reduce muscle overactivity. However, a standardized protocol should be used. ANRP seems to be the most valid position for assessing gastrocnemius elastic stiffness in neurological populations. This should be kept in mind for the choice of positioning in further studies.

Biomechanical assessment of ligament maturation after arthroscopic ligament reconstruction of the anterior talofibular ligament

BACKGROUND

Many techniques have been described for lateral ankle ligament reconstruction. Although the biomechanical properties of gracilis tendons are different from those of ligaments, the use of a gracilis tendon autograft is a popular option for anatomical reconstruction. Graft maturation and the biomechanical processes over time remain unclear. This study describes changes in graft stiffness following anterior talofibular ligament (ATFL) reconstruction and graft reaction to varus stress.

HYPOTHESIS

The reconstruction would be stiffer than the native ATFL, but would decrease during follow-up.

METHODS

Twenty patients were prospectively included after arthroscopic reconstruction of the ATFL and calcaneofibular ligament for ankle stabilization. All patients were followed up 3, 6, and 12 months after surgery to assess graft stiffness by shear wave elastography (SWE) at different angles of varus in the ankle. At one year the EFAS and AOFAS functional scores were obtained. A control group of twenty healthy subjects were included to compare graft stiffness to that of a native ATFL.

RESULTS

The stiffness of the native ATFL in the control group was 12.8 +/- 2.4 kPa in neutral position, 18.4 +/- 4.8 kPa at 15 ° of varus, 31.9 +/- 6.6 kPa at 30 ° of varus. One year after surgery, graft stiffness was statistically higher and averaged 56 +/- 9 kPa, 70.2 +/- 11.6 kPa and 84.9 +/- 10.5 kPa, respectively. Postoperative graft stiffness at three, six, and twelve months was not correlated with any of these scores, reflecting patient satisfaction and good function at one year.

CONCLUSION

Graft stiffness decreases over time but remains four times stiffer than that of a native ATFL at one year in the neutral position. ATFL graft stiffness at one year during varus stress appears to be different from that of a native ATFL.

LEVEL OF EVIDENCE

III.

Shear wave elastography characteristics of the gastrocnemius muscle in postural instability gait disorder vs tremor dominant Parkinson's disease patients

OBJECTIVES

This study explored the characteristics of muscle stiffness of lower gastrocnemius in resting and exercise states in patients with postural instability gait difficulty (PIGD) and tremor dominant (TD) Parkinson's disease patients using shear wave elastography (SWE).

DATA AND METHODS

75 PD patients from the Department of Parkinson's Disease Center in the Hospital from September 2021 to December 2022 were prospectively included, including 44 patients with PIGD and 31 with TD. In the same period, 40 healthy subjects matching gender and age were included as the control group. SWE was used to detect Young's modulus of both sides (right and left, R- and L-) of the lateral head of the gastrocnemius in resting (YM1) and exerciser states (YM2) in all participants and the absolute difference Young's modulus between resting and exercise state (ΔYM) was calculated.

RESULTS

R-YM2 and R-ΔYM were the highest in the normal controls, followed by the TD group, and lowest in the PIGD group. There were no differences in L-YM2 and L-ΔYM between the PIGD group and the TD group (all p > 0.05), but they were lower than those in the normal control group (all p < 0.05). In addition, R-YM2 and R-ΔYM were negatively correlated with disease duration and UPDRS III scores in the PIGD group (all p < 0.05). R-ΔYM has the highest value in the differential diagnosis of PIGD and TD patients. The area under the receiver operating characteristic curve (ROC) curve is 0.812 (95%CI, 0.730-0.893), and the diagnostic threshold is 120.5 Kpa with a sensitivity of 63.6%, a specificity of 90.1%, a positive predictive of 80%, and a negative predictive value of 80%.

CONCLUSION

Shear wave elastography is a sensitive ultrasound method for evaluating muscle strength in patients with PIGD and TD. It also provides a new biological indicator to distinguish between different phenotypes of patients with PD.

Ultrasound Shear Wave Elastography of the Arch-Supporting Structures in Symptomatic Flatfoot: A Pilot Study

Background

The posterior tibial tendon (PTT), deltoid ligament, and spring ligament are often torn or attenuated in patients with progressive collapsing foot deformity. The goal of this pilot study was to measure the ultrasound shear wave velocity (SWV) of these arch-supporting structures in feet with varying degrees of deformity to improve our understanding of their role in the progression of deformity.

Methods

Two observers measured the SWV of the supramalleolar and inframalleolar PTT in long and short axes, in the tibiospring portion of the deltoid ligament, and in the superomedial band of the spring ligament in 8 neutrally aligned feet, 5 asymptomatic flatfeet, and 7 symptomatic flatfeet. Each measurement was repeated 3 times both with and without an applied eversion stress.

Results

Average SWV was lower at all locations in the symptomatic flatfeet compared with normal feet, but these differences were statistically significant only for the inframalleolar PTT and the spring ligament. Externally applied stress led to an increase in the SWV of the ligaments but a paradoxical decrease in the SWV in the supramalleolar PTT. The SWV of the PTT was lower along the short axis compared with the long axis.

Conclusion

SWV may be useful in evaluating the severity of degenerative disease of arch-supporting structures, but further study is needed before this technique can be applied clinically.

Level of Evidence

Level III, case-control study.

Epimuscular myofascial force transmission between nerve and myotendinous unit: A shear-wave elastography study

INTRODUCTION

Epimuscular myofascial force transmission can occur bidirectionally between muscles and nerves through a connecting neurovascular tract. The purpose of this study was to determine whether a neurodynamic stress test produces stiffness changes in the adjacent myotendinous complex. The authors also assessed which anatomical variables had an impact on elasticity changes provoked by the maneuver.

METHODS

A convenience sample of healthy adults (n = 39) recruited from a university population who met the inclusion criteria participated voluntarily in this study. Using Shear-Wave elastography, stiffness data were obtained for the ulnar nerve, flexor carpi ulnaris tendon and muscle before and after a neural tensioning maneuver.

RESULTS

Following an ulnar nerve stretch, statistically significant differences were obtained in neural stiffness increase in nerve (p < 0.001), tendon (p < 0.001) and muscle (p = 0.046), with a moderate (d = 0.538), small (d = 0.485) and small (d = 0.224) effect sizes, respectively. The changes obtained were greater in those individuals with a smaller anatomical distance between nerve and tendon.

CONCLUSIONS

Alterations in peripheral neural tissue tension involves elasticity changes in adjacent musculoskeletal tissue mediated by the neurovascular tract. Collateral force transmission was determined by the individual anatomical differences of each subject. Future research should assess whether the observed increase in myotendinous stiffness due exclusively to the passive transmission of force through the connective bridges between the two tissues studied or if there is a "neuroprotective" muscle contraction following neural stress.

Numerical modeling of the abdominal wall biomechanics and experimental analysis for model validation

The evaluation of the biomechanics of the abdominal wall is particularly important to understand the onset of pathological conditions related to weakening and injury of the abdominal muscles. A better understanding of the biomechanics of the abdominal wall could be a breakthrough in the development of new therapeutic approaches. For this purpose, several studies in the literature propose finite element models of the human abdomen, based on the geometry of the abdominal wall from medical images and on constitutive formulations describing the mechanical behavior of fascial and muscular tissues. The biomechanics of the abdominal wall depends on the passive mechanical properties of fascial and muscle tissue, on the activation of abdominal muscles, and on the variable intra-abdominal pressure. To assess the quantitative contribution of these features to the development and validation of reliable numerical models, experimental data are fundamental. This work presents a review of the state of the art of numerical models developed to investigate abdominal wall biomechanics. Different experimental techniques, which can provide data for model validation, are also presented. These include electromyography, ultrasound imaging, intraabdominal pressure measurements, abdominal surface deformation, and stiffness/compliance measurements.

Effects of a Manual Treatment on Lumbar Microcirculation and Tissue Stiffness Following Submaximal Eccentric Trunk Extensor Exercise: A Randomized Controlled Trial

Recent studies have shown that the extramuscular connective tissue (ECT) is thickened and stiffened in delayed onset muscle soreness (DOMS). However, contrarily to the normal population, severe DOMS is rare in athletes or highly trained individuals. The present randomized, controlled trial therefore aimed to investigate pain as well as microcirculation and stiffness of the ECT and the erector spinae muscle following submaximal eccentric trunk extension exercise not causing DOMS. The effect of manual treatment by a therapist (myofascial release; MFR) on these parameters was to be studied. Trained healthy participants (n = 21; 31.3 ± 9.6 years; > 4 h exercise per week) performed submaximal eccentric exercise of the trunk extensors. One group was manually treated (n = 11), while the other group (n = 10) received placebo treatment with sham laser therapy. Stiffness of the ECT and the erector spinae muscle (shear wave elastography), microcirculation (white light and laser Doppler spectroscopy), palpation pain (100 mm visual analogue scale, VAS) and pressure pain threshold (indentometry, PPT) were assessed before (t0), 24 h (t24) and 48 h (t48) after conditions. Erector spinae muscle stiffness increased after eccentric exercise from t0 to t24 (0.875 m/s) and from t0 to t48 (0.869 m/s). After MFR, erector spinae muscle stiffness decreased in contrast to placebo treatment at t24 (-0.66 m/s), while ECT stiffness remained unchanged. Oxygen saturation increased (17-20.93%) and relative haemoglobin decreased (-9.1 - -12.76 AU) after eccentric exercise and MFR differed from placebo treatment at t48 (-3.71 AU). PPT differed after MFR from placebo treatment at t48 (20.69 N/mm), while VAS remained unchanged. Multiple linear regression showed that ECT stiffness and group membership predicted erector spinae muscle stiffness. MFR could have a positive effect on pain, microcirculation and muscle stiffness after submaximal eccentric exercise, suggesting better recovery, which needs to be confirmed by future work.

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.

Quantifying lower limb muscle stiffness in typically developing children and adolescents using acoustic radiation force impulse shear wave elastography (ARFI/SWE)-a pilot study

OBJECTIVE

To investigate and quantify age-related changes in lower limb muscle stiffness in typically developing children and adolescents using acoustic radiation force impulse shear wave elastography.

MATERIALS AND METHODS

Shear wave velocities of bilateral rectus femoris, tibialis anterior, and medial gastrocnemius muscles at rest were obtained in typically developing children and adolescents aged 3 to 18 years. The participants were classified into three age groups: Group 1 (children), 3 to 7 years old; Group 2, 8 to 12 (pre-adolescent); and Group 3 (adolescent), 13 to 18. The shear wave velocities of muscle were compared across the three age groups, as well as compared between right- and left-side limbs. The correlation between shear wave velocities and body weight or body mass index was assessed.

RESULTS

Of the 47 participants, 21 were in Group 1, 17 in Group 2, and 9 in Group 3. There were no significant differences among the three age groups' shear wave velocities of bilateral lower limb muscles, and no significant differences between right and left sides. There was no correlation between muscle stiffness and body weight or body mass index.

CONCLUSION

The present pilot study applied acoustic radiation force impulse shear wave elastography to quantify lower limb muscle stiffness in typically developing children and adolescents aged 3 to 18 years, suggesting no marked change in muscle stiffness occurs as they develop.

Quantifying Plantar Flexor Muscles Stiffness During Passive and Active Force Generation Using Shear Wave Elastography in Individuals With Chronic Stroke

OBJECTIVES

This study aims to investigate the mechanical properties of paretic and healthy plantar flexor muscles and assesses the spatial distribution of stiffness between the gastrocnemius medialis (GM) and lateralis (GL) during active force generation.

METHODS

Shear wave elastography measurements were conducted on a control group (CNT, n=14; age=59.9±10.6 years; BMI=24.5±2.5 kg/m2) and a stroke survivor group (SSG, n=14; age=63.2±9.6 years; BMI=23.2±2.8 kg/m2). Shear modulus within the GM and GL was obtained during passive ankle mobilization at various angles of dorsiflexion (P0 =0°; P1=10°; P2=20°; P3=-20° and P4=-30°) and during different levels (30%, 50%, 70%, 100%) of maximal voluntary contraction (MVC). Muscle activations of GM, GL, soleus and tibialis anterior were also evaluated.

RESULTS

The results revealed a significant increase in passive stiffness within the paretic plantar flexor muscles under high tension during passive mobilization (p<0.05). Yet, during submaximal and maximal MVC, the paretic plantar flexors exhibited decreased active stiffness levels (p<0.05). A notable discrepancy was found between the stiffness of the GM and GL, with the GM demonstrating greater stiffness from 0° of dorsiflexion in the SSG (p<0.05), and from 10° of dorsiflexion in the CNT (p<0.05). No significant difference in stiffness was observed between the GM and GL muscles during active condition.

CONCLUSION

Stroke affects the mechanical properties differently depending on the state of muscle activation. Notably, the distribution of stiffness among synergistic plantar flexor muscles varied in passive condition, while remaining consistent in active condition.

Biomechanical evaluation of the anterior talo-fibular and calcaneo-fibular ligaments using shear wave elastography in young healthy adults

BACKGROUND

The objective of this study was to evaluate the stiffness of the anterior talo-fibular ligament (ATFL) and calcaneo-fibular ligament (CFL) using shear wave elastography (SWE) with the ankle in the neutral position and in varus, in young healthy adult volunteers. We also evaluated the reliability and reproducibility of the SWE measurements.

HYPOTHESIS

The stiffness of both ligaments increases with increasing ankle varus. SWE may be a reliable tool for evaluating the lateral collateral ligament complex of the ankle.

MATERIAL AND METHODS

We used SWE to evaluate both ankles of each of 20 healthy volunteers (10 females and 10 males). For each test, the foot was placed on a hinged plate and tested in the neutral position and in 15° and 30° of varus. Stiffness was evaluated based on shear wave velocity (SWV).

RESULTS

Stiffness of both the ATFL and CFL was minimal in the neutral position (2.06m/s and 3.43m/s, respectively). Stiffness increased significantly for both ligaments in 15° of varus (2.48m/s and 4.11m/s, respectively; p<0.0001) and was greatest in 30° of varus (3.15m/s and 4.57m/s, respectively; p<0.0001). ATFL stiffness was greater in males than in females in 15° (p=0.04) and 30° (p=0.02) of varus. For the CFL, in contrast, stiffness was not different between males and females. Stiffness of the ATFL and CFL was not associated with age, dominant side, height, or foot morphology. No correlations were found between stiffness of the two ligaments in any of the positions. Repeating each measurement three times produced excellent concordance for both ligaments in all three positions.

CONCLUSION

The ATFL and CFL are the main lateral stabilisers of the ankle, and each exerts a specific function. Their stiffness increases with the degree of varus. This study describes a protocol for evaluating ATFL and CFL density by SWE, which is a reliable and reproducible technique that provides a normal range.

LEVEL OF EVIDENCE

IV.

The Influence of Mobility Training on the Myofascial Structures of the Back and Extremities

BACKGROUND

The subject of the study was the effect of a multicomponent program (Mobility Routine) on muscular and fascial stiffness, flexibility, subjective well-being, and body perception.

METHODS

The assumption was that high physical stress affects myofascial structures and joint range of motion. The assessment of myofascial stiffness employed a Shear Wave Elastography. The joint flexibility, pressure pain threshold, and subjective experiences with regard to tension, pain, and general discomfort were documented.

RESULTS

In the CT group, a greater increase in stiffness was measured in fewer measurement areas compared to the MR group. MR demonstrated superior gains in flexibility compared to CT. Both groups experienced significant reductions in pain, tension, and discomfort. In conclusion, repetitive motion patterns akin to CT lead to increased myofascial stiffness, whereas MR yields more balanced stiffness development, compensates for asymmetries, and improves body awareness.

CONCLUSIONS

Hence, this study highlights the advantages of mobility training over Crosstrainer exercises and provides valuable insights for the recommendation of training regimens aiming at the enhancement of musculoskeletal functionality and overall well-being.

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.

Acute Effects of Stretching Exercises on Posterior Chain: Analysis of Shear Modulus by Elastography SSI

The posterior chain muscles of the lower limb include the hamstrings and triceps surae, along with the Achilles tendon. This study aimed to investigate the acute effects of static stretching exercises commonly used in clinical and training settings on the shear modulus (µ) of these muscles and tendon using Supersonic Shear-Wave Imaging (SSI) elastography. Fifteen healthy adults participated in the study, performing stretching exercises for hamstrings and triceps surae. Shear modulus and joint range of motion (ROM) were measured before and after the stretching protocols. The hip and ankle mean ROM significantly increased by 19.27% and 24.10%, respectively. However, the stretching protocol did not significantly alter in µ of the hamstrings, the gastrocnemius muscles, and the Achilles tendon. K-means clustering analysis identified a group where the subjects with lower initial ROM showed higher amplitude gains and a significant decrease in the semimembranosus stiffness after stretching. These findings suggest that the stretching protocol was effective in improving joint mobility but not sufficient to elicit immediate mechanical changes in muscle and tendon stiffness. Neural adaptations and nonmuscular structures might contribute to increased ROM. The study highlights the importance of considering individual initial ROM and subsequent responses when evaluating the effects of stretching exercises on muscle and tendon properties.

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.

Biomechanical evaluation of the spring ligament and the posterior tibial tendon by shear-waves elastography: validation of a reliable and reproducible measurement protocol

PURPOSE

The anatomy of the spring ligament complex, as well as its pathology, is not well known in daily clinical practice. The purpose of this study was to evaluate the shear-wave elastography properties of the spring ligament and the posterior tibial tendon in healthy adults, and to assess the reliability and reproducibility of these measurements.

METHODS

Shear-wave elastography was used to evaluate both ankles in 20 healthy patients (10 females/10 males) resting on a hinge support with their ankles in neutral, valgus 20° and varus 30° positions. The stiffness of the spring ligament and posterior tibial tendon was assessed by measuring the speed of shear wave propagation through each structure.

RESULTS

Posterior tibial tendon and spring ligament reach a maximum estimated stiffness in valgus 20° position (7.43 m/s vs 5.73 m/s, respectively). Flat feet were associated with greater spring ligament stiffness in the 20° valgus position (p = 0.01), but not for the posterior tibial tendon (p = 0.71). The physiologic weightbearing hindfoot attitude had no impact on the stiffness of the posterior tibial tendon or the spring ligament, regardless of the analysis position. Intra- and inter-observer agreements were all excellent for spring ligament stiffness, regardless of ankle position, and were good or excellent for posterior tibial tendon.

CONCLUSIONS

This study describes a protocol to assess the stiffness of tibialis posterior and the spring ligament by shear-wave elastography, which is reliable, reproducible, and defines a corridor of normality. Further studies should be conducted to define the role of elastography for diagnosis/ evaluation of pathology, follow-up, or surgical strategies.

A Multivariable Model Based on Ultrasound Imaging Features of Gastrocnemius Muscle to Identify Patients With Sarcopenia

OBJECTIVES

Low skeletal muscle mass, strength, or somatic function are used to diagnose sarcopenia; however, effective assessment methods are still lacking. Therefore, we evaluated the effectiveness of ultrasound in identifying patients with sarcopenia.

METHODS

This study included 167 patients, 78 with sarcopenia and 89 healthy participants, from two hospitals. We evaluated clinical factors and five ultrasound imaging features, of which three ultrasound imaging features were used to create the model. In both the training and validation datasets, the sarcopenia detection performances of chosen ultrasonic characteristics and the constructed model were evaluated using receiver operating characteristic (ROC) curves. The predictive performance was evaluated by area under the ROC (AUROC), calibration, and decision curves.

RESULTS

There were statistically significant differences in muscle thickness (MT) of gastrocnemius medialis muscle (GM), flaky myosteatosis echo (FE), pennation angle (PA), average shear wave velocity (SWV) in the relaxed state (RASWV), and average SWV in the passive stretched state (PASWV) between sarcopenic and normal subjects. PA, RASWV, and PASWV were effective predictors of sarcopenia. The AUROC (95% confidence interval) for these three parameters were 0.930 (0.882-0.978), 0.865 (0.791-0.940), and 0.849 (0.770-0.928), respectively, in the training set, and 0.873 (0.777-0.969), 0.936 (0.878-0.993), and 0.826 (0.716-0.935), respectively, in the validation set. The combined model had better detection power. Finally, the calibration curve showed that the combined model had good prediction accuracy.

CONCLUSION

Our model can be used to identify sarcopenia in primary medical institutions, which is valuable for the early recognition and management of sarcopenia patients.

Utility of Ultrasound Elastography to Evaluate Poststroke Spasticity and Therapeutic Efficacy: A Narrative Review

Poststroke spasticity (PSS) is a common complication that affects function and daily self-care. Conservative PSS treatments include traditional rehabilitation, botulinum toxin injection, and extracorporeal shock wave therapy. Currently, the Modified Ashworth Scale and Modified Tardieu Scale are widely used tools to clinically evaluate spasticity, but the best tool for PSS assessment remained controversial. Ultrasound elastography (UE), including shear wave and strain image as the emerging method to evaluate soft tissue elasticity, became popular in clinical applications. Spastic biceps and gastrocnemius muscles were reported to be significantly stiffer compared to nonparetic muscles or healthy control using shear wave or strain elastography. More studies investigated the utility, reliability, and validity of UE in patients with PSS, but the contemporary consensus for the utility of UE in the measurement and therapeutic follow-up of PSS remained lacking. Therefore, this narrative review aimed to appraise the literature on the shear wave and strain elastography on PSS and summarize the roles of UE in assessing the therapeutic efficacy of different PSS interventions.

Stiffness changes in internal rotation muscles of the shoulder and its influence on hemiplegic shoulder pain

Background

Hemiplegic shoulder pain (HSP) is a common complication in patients with stroke. The pathogenesis of HSP is complex, and muscle hypertonia, especially the hypertonia of internal rotation muscles of the shoulder, may be one of the important causes of shoulder pain. However, the relationship between muscle stiffness and HSP has not been well studied. The purpose of this study is to explore the correlations between the stiffness of internal rotation muscles and clinical symptoms in patients with HSP.

Methods

A total of 20 HSP patients and 20 healthy controls were recruited for this study. The stiffness of internal rotation muscles was quantified using shear wave elastography, and Young's modulus (YM) of the pectoralis major (PM), anterior deltoid (AD), teres major ™, and latissimus dorsi (LD) were measured. Muscle hypertonia and pain intensity were evaluated using the Modified Ashworth Scale (MAS) and Visual Analog Scale (VAS), respectively. The mobility of the shoulder was evaluated using the Neer score. The correlations between muscle stiffness and the clinical scales were analyzed.

Results

YM of internal rotation muscles on the paretic side was higher than that of the control group in the resting and passive stretching positions (P < 0.05). YM of internal rotation muscles on the paretic side during passive stretching was significantly higher than that at rest (P < 0.05). YM of PM, TM, and LD during passive stretching were correlated with MAS (P < 0.05). In addition, the YM of TM during passive stretching was positively correlated with VAS and negatively correlated with the Neer score (P < 0.05).

Conclusion

Increased stiffness of PM, TM, and LD was observed in patients with HSP. The stiffness of TM was associated with pain intensity of the shoulder and shoulder mobility.

Assessment of ultrasound shear wave elastography: An animal ex-vivo study

OBJECTIVES

To explore the influence of the surrounding environment of the target tissue, lesion size, and rectangular sampling box size on shear wave speed (SWS).

METHODS

The tendon SWS was acquired ex-vivo. Then the tendons were dissected and buried in the couplant (gel) and evaluated by two-dimensional shear wave elastography (2D-SWE). Finally, the tendons were placed in the isolated muscles to simulate the intramuscular lesions, and their elasticity was tested under two rectangular sampling box conditions. The isolated complete liver SWS was acquired. Similarly, the large and small pieces of livers were cut out, placed in the muscles, and assessed by SWE under two rectangular sampling box conditions. The SWS acquired under different conditions was compared. Variability was evaluated using the coefficient of variation (CV). The intraclass correlation coefficient (ICC) was used to evaluate repeatability.

RESULTS

The SWS of the tendons ex-vivo, buried in the couplant and placed in the isolated muscles showed significant differences (p < 0.001). The ex-vivo condition produced the highest SWS and CV values. There were significant differences in SWS of livers with different sizes placed in muscles (p < 0.001). The highest SWS value was associated with small pieces of livers. No significant difference was found in SWS acquired under different rectangular box sizes (p > 0.05).

CONCLUSIONS

Under the present study conditions, the surrounding environment of the target tissue makes a big difference to lesion SWS values. The lesion size will affect the assessment of its inherent elasticity. The size of the sampling frame has no significant effect on the tissue SWS.

Tibialis posterior muscle stiffness assessment in flat foot subjects by ultrasound based Shear-Wave Elastography

BACKGROUND

Few methodologies are used to assess Tibialis Posterior muscle stiffness. Those present limitations leading to a lack of evidence. Muscle stiffness assessment can help in the injuries risk factors identification while coupling with Ultrasound based Shear-Wave Elastography for its management. However, a precise and reliable methodology needs to be utilized to increase stiffness accuracy among the entire Tibialis Posterior muscle. Therefore, this study aims to investigate the stiffness association between Tibialis posterior deep and superficial layer and between flat and neutral footed subjects.

METHODS

The sample consisted of 18 participants, where 9 subjects represent the flatfoot group and 9 the neutral foot group. Only the subjects who presented a Navicular Drop Test value of > 9 mm were included in the flatfooted group. All participants were submitted to the Tibialis posterior stiffness assessment with the help of Ultrasound base Shear-Wave Elastography in a lying supine position. Association between Tibialis Posterior deep and superficial layers were determined by Pearson's correlation analysis and group differences were assessed using the U-Mann Whitney test in the comparison between flat foot and neutral foot group (p < 0.05).

RESULTS

No significant correlations between Tibialis Posterior layers stiffness were found (p = 0.194), nor in the comparison between both neutral and flat foot groups (p = 0.424/p = 0.258).

CONCLUSION

Among participants, no associations between tibialis posterior layers stiffness were found. Also, we did not find any differences in the stiffness between flat and neutral foot groups. In this study, the stiffness did not differentiate flat-footed subjects from neutral subjects.

Viscoelasticity in trapezius myofascial pain syndrome: quantitative assessment using Real-Time Shear-Wave Elastography

OBJECTIVE

To investigate the differences in the viscoelastic properties between normal trapezius muscles and those in patients with trapezius myofascial pain syndrome (MPS) using real-time shear-wave elastography (SWE).

MATERIALS AND METHODS

This study included 31 patients with trapezius MPS and 31 volunteers. Sixty-one trapezius muscles (41 and 20 on the affected and non-affected side, respectively) of patients with MPS and 62 normal trapezius muscles in volunteers were assessed. Conventional ultrasonic parameters, including skeletal muscle thickness, resistance index (RI), and mean shear wave velocity (SWVmean) of trapezius muscles, were obtained in the seated position with the shoulders and neck relaxed. The daily neck leaning time (unit:hours) of all participants was obtained using a questionnaire.

RESULTS

Ultrasound showed no statistically significant differences in thickness or RI of the trapezius muscles of the affected and non-affected sides in MPS patients versus normal trapezius muscles (p = 0.976 and 0.106, respectively). In contrast, the SWVmean of trapezius muscles in patients with MPS was significantly higher than that of normal trapezius muscles in both the affected and non-affected sides (4.41 ± 1.02 m/s vs. 3.35 ± 0.79 m/s, p < 0.001; 4.05 ± 0.63 m/s vs. 3.35 ± 0.79 m/s, p = 0.002). There was no significant difference between the SWVmean of the trapezius muscles on the affected and non-affected sides in patients with MPS (4.41 ± 1.02 m/s vs. 4.05 ± 0.63 m/s, p = 0.225). Correlation analysis showed that daily neck forward time was positively correlated with the SWVmean of the trapezius muscles on the affected and non-affected sides in patients with MPS (r = 0.635, p < 0.001; r = 0.576, p = 0.008).

CONCLUSION

SWE can quantitatively evaluate stiffness of trapezius muscles in patients with trapezius MPS. The stiffness of both affected and non-affected trapezius muscles increased in patients with trapezius MPS, and the degree of increase positively correlated with the time of cervical forward leaning.

A shear-wave sonoelastography investigation of calf muscle pump biomechanics in patients with chronic venous disease and healthy controls

BACKGROUND

chronic venous disease (CVD) is a common progressive disorder with incompetence of calf muscle pump due to weakness and ankle mobility abnormality is an important etiological factor in CVD, but the biomechanical properties of calf muscle pump are remain unknown.

OBJECTIVES

The purpose of the present study was to evaluate group differences between the biomechanical properties changes of the medial gastrocnemius muscle (GM) and its fascias in participants with CVD and healthy controls.

METHODS

In this case-control study, thirty patients with CVD in three equal groups (mild: C1 - C2, moderate: C3 - C4, severe: C5 - C6) and 20 healthy subjects in a control group participated. The medial GM and its fascias shear modulus (stiffness) were measured using a shear-wave sonoelastography in rest and active dorsiflexion positions of ankle joint.

RESULTS

The results of variance (ANOVA) analysis showed a significant difference in shear wave elastography (SWE) value between the groups for medial GM and its fascias at rest and active dorsiflexion of the ankle joint (P < 0.05). There was a statistically significant increase in SWE value of the medial GM and its fascias in moderate (c3-c4) and severe CVD groups (C5-C6) compared to the control and mild (C1-C2) CVD groups. A positive correlation was discovered between disease grades and the medial GM and its fascias SWE in patients with CVD ranging between r = 0.846 to 0.891; P < 0.001.

CONCLUSION

An alteration stiffness in calf myofascial pump as compared to control group indicated an impaired myofascial biomechanics. Calf myofascial SWE may be valuable information in the diagnosis and follow-up processes of patients with CVD.

Variability of Biceps Muscle Stiffness Measured Using Shear Wave Elastography at Different Anatomical Locations With Different Ultrasound Machines

Shear wave elastography is an emerging diagnostic tool used to assess for changes in the stiffness of muscle. Each region of the muscle may have a different stiffness; therefore, the anatomical region should be carefully selected. Machine vendors each have unique methods for calculating the returned stiffness values and, consequently, a high level of agreement in measurement between machines (quantified using the intraclass correlation coefficient [ICC] and Bland-Altman analysis) will allow research findings to be translated to the clinic. This study assessed three locations within the biceps muscle (50% and 75% of the distance between the acromioclavicular joint and antecubital fossa, and superior to distal myotendinous junction [MTJ]) of 32 healthy volunteers with two different machines, the Canon Aplio i600 and SuperSonic Imagine Aixplorer (SSI), to compare the reported shear wave velocities and the variability by coefficient of variation (CV) and ICC. There was no difference in the CV between machines, but a significant difference in the CV at muscle regions, with the 75% location having a 40.2% reduction in CV. The 75% location had the highest ICC values with good posterior mean ICCs of 0.84 on the Canon and 0.83 on the SSI. The 50% and MTJ locations had poor ICC values. The 75% location provided the lowest CV and highest ICC and should be used for future stiffness assessments.

Weakness of lower limb muscle in symptomatic peripheral artery disease with media sclerosis detected by ultrasound shear wave elastography

Background: Symptomatic peripheral arterial disease (PAD) is difficult to non-invasively diagnose in the presence of calcified, media sclerotic arteries that are incompressible by blood pressure cuffs. Standard ankle-brachial index (ABI) measurements in these PAD patients are very often not helpful. Shear wave elastography (SWE) is a modern ultrasound technique to detect peripheral muscle stiffness changes i.e. muscle weakness during exercise. In a pilot study, we examined whether SWE could be a reproducible tool for diagnosing ischemic loss of muscle stiffness in patients with PAD and concomitant arterial media sclerosis. Patients and methods: N=13 consecutive patients with peripheral artery disease and media sclerosis were enrolled in the pilot study. All 13 patients were symptomatic in different stages of their PAD due to hemodynamically relevant arterial stenosis or occlusions of limb arteries as confirmed by oscillography, color-coded duplex sonography or angiography. Results: ABI measurements were invalid in all 13 patients. Mean SWE measurements of medial gastrocnemius muscles showed a significant transient muscle stiffness loss (weakness) at maximum exercise (active dorsal flexion of the foot, 103.4±25.9 kPa on the asymptomatic vs. 62.5±21.9 kPa on the symptomatic limb (p<0.001). Conclusions: SWE can reproducibly detect peripheral muscle weakness during exercise in the symptomatic leg of media sclerotic PAD patients. SWE of lower limb muscles may help to identify symptomatic PAD in patients presenting with invalid ABI measurements and unclear vascular status.

Ankle syndesmosis biomechanical evaluation by shear-waves elastography in healthy young adults: Assessment of the reliability and accuracy of the measurements and definition of a corridor of normality

BACKGROUND

Aims of this study were: 1/ to evaluate the shear wave speed (SWS) properties of the anteroinferior tibiofibular ligament (AITFL) and the distal interosseous membrane (DIOM) in neutral, dorsal flexion and plantar flexion positions in a cohort of healthy adult volunteers; 2/ to assess the reliability and reproducibility of these measurements.

METHODS

Both ankles were analyzed by shear wave elastography (SWE) in 20 healthy patients (10 females/10 males) standing on a hinge support with their ankles in neutral, 20° dorsal flexion and 30° plantar flexion positions. Stiffness of AITFL and DIOM was evaluated by SWS measurement.

RESULTS

The SWS of AITFL and DIOM were minimal in the plantar flexion position (4.28 m/s [2.65-5.11] and 3.35 m/s [1.69-4.55], respectively). It increased significantly for both ligaments in neutral position (4.69 m/s [3.53-5.71] and 3.81 m/s [1.91-4.74], respectively; p < 0.0001), and reached their maximum values in dorsal flexion (6.58 m/s [5.23-8.34] and 4.79 m/s [3.07-6.19], respectively; p < 0.0001). There was no correlation between each ligament regardless the positions. SWS of AITFL was independent of demographic characteristics analyzed. SWS of DIOM was negatively correlated with height in dorsal flexion (ρ = -0.35; p = 0.03) and in plantar flexion (ρ = -0.37; p = 0.02). Female gender was associated with increased DIOM SWS in neutral (p = 0.005), dorsal flexion (p = 0.003), and plantar flexion (p = 0.001) positions. Moreover, foot morphology (foot arch, hind foot frontal deviation) did not impact AITFL nor DIOM SWS. Inter- and intra-observer measurements were all good or excellent.

CONCLUSION

The AITFL and DIOM, stabilizers of the distal tibiofibular syndesmosis, increase in stiffness while dorsal flexion increases. This study describes a reliable and reproducible protocol to assess their stiffness by SWE, and defines a corridor of normality.

Biomechanical assessment of the central band of the interosseous membrane using shear wave elastography: reliability and reproducibility

The interosseous membrane of the forearm is an essential structure for the stability of the forearm skeleton, the most important part being the central band. The purpose of this study was to determine if shear wave elastography, a non-invasive ultrasound technique, can be used to measure shear wave speed in the central band and quantify stiffness. Fifteen healthy adult subjects were included (30 forearms). The participants forearms were positioned on an articulated plate, with their hand in neutral, pronated and then supinated positions of 30°, 60° and 90°. The shear wave speed was highest in 90° pronation (4.4 m/s (SD 0.3)) and 90° supination (4.4 m/s (SD 0.27)) indicating maximum stiffness in these positions. Its minimum value was in the neutral position, and either in 30° pronation or supination (3.5 m/s (SD 0.3)). Intra- and interobserver agreement was excellent, regardless of probe positioning or forearm mobilization. This study presents a reliable shear wave elastography measurement protocol to describe the physiological function of the central band of the interosseous membrane in healthy adults.Level of evidence: IV.

Differences in Medial and Lateral Gastrocnemius Stiffness after Exercise-Induced Muscle Fatigue

Muscles are affected at the cellular level by exercised-induced fatigue, inducing changes in their stiffness. Examining muscle stiffness can improve the knowledge of various pathologic conditions, such as pain and injury. The objective of this study was to examine the stiffness of the medial gastrocnemius (MG) muscle and the lateral gastrocnemius (LG) muscle to determine the changes in stiffness, and to assess the differences in the stiffness between the MG and the LG, as affected by muscle fatigue measured using shear wave elastography (SWE) and a MyotonPRO after inducing muscle fatigue. A total of 35 healthy young adults participated in the study. The stiffness of the MG and the LG were assessed before and after a muscle fatigue protocol (MFP), which included three sets of 50 eccentric contractions of the calf muscles of the dominant leg, at rest, and at maximum voluntary contraction (MVC). The measurements were taken with SWE and the MyotonPRO simultaneously. Compared to baseline, the resting stiffness of the MG and the LG significantly increased immediately, 24 h, and 48 h after muscle fatigue (p < 0.05); however, during MVC, the stiffness of the MG decreased (p < 0.05) and that of the LG showed no change (p > 0.05). When the stiffness of the MG and the LG were compared before and after the MFP, changes in the stiffness of the MG were significantly greater than those in the LG (p < 0.05). This signifies that the MG was more affected by the exercise-induced muscle fatigue than was the LG. The assessment of musculoskeletal tissue and its characteristics, before and after eccentric exercise, is crucial in the prevention of overuse injuries associated with repeated exposure to both low and high levels of force.

Effects of Maximal Eccentric Exercise on Deep Fascia Stiffness of the Knee Flexors: A Pilot Study using Shear-Wave Elastography

The deep fascia is intimately linked to skeletal muscle and may be involved in delayed onset muscle soreness (DOMS). The present study therefore explored the effect of eccentric exercise on fascia stiffness and its relation with DOMS. Healthy active male adults (n = 19, 27 ± 4 years) performed 6 x 10 maximal eccentric knee flexions using an isokinetic dynamometer. Before (baseline) as well as immediately (T0), 1 hour (T1), and each day up to 72 hours (T24 to T72) afterwards, shear wave elastography was used to measure the mechanical stiffness of the biceps femoris muscle and the overlying fascia. As a surrogate of DOMS, pain upon palpation was captured by means of a 100mm visual analogue scale. While muscle stiffness remained unchanged (p > 0.05), deep fascia stiffness increased from baseline to T24 (median: 18 kPa to 21.12 kPa, p = 0.017) and T72 (median: 18 kPa to 21.3 kPa, p = 0.001) post-exercise. Linear regression showed an association of stiffness changes at T24 and pressure pain at T72 (r² = 0.22, p < 0.05). Maximal eccentric exercise leads to a stiffening of the fascia, which, in turn, is related to the magnitude of future DOMS. Upcoming research should therefore gauge the effectiveness of interventions modifying the mechanical properties of the connective tissue in order to accelerate recovery.

Effect of hip and knee joint angles on resting hamstring muscles rigidity in men and women

PURPOSE

Hamstring muscle strains are one of the most common injuries in sports practice, for both men and women. However, sex disparities in the rate of muscle injuries have been observed. As these muscular injuries usually occur at long muscle length, this study aimed to determine the effect of sex on hamstring muscles' resting rigidity under different stretching conditions.

METHODS

The shear wave speed (SWS) of resting hamstring muscles was measured in 12 men and 12 women in different hip and knee positions (hip extended with knee flexed, hip flexed with knee extended, both joints extended and both joints flexed).

RESULTS

Combining all the positions, the SWS of the semitendinosus was higher in men than in women (2.96 vs. 2.71 m.s^-1). Regardless of sex, a significant rise in SWS was systematically observed when the semimembranosus was stretched (1.86, 2.37, 2.76 and 4.39 m.s^-1) but it was neither the case for the semitendinosus (p = 0.82) nor for the biceps femoris (p = 0.50). Finally, differences in SWS among the hamstring muscles were only observed at the longest muscle length, with greater SWS values for the semimembranosus and semitendinosus in comparison with the biceps femoris (4.39 and 4.12 vs. 3.38 m.s^-1 respectively).

CONCLUSION

In conclusion, a sex difference was only observed in the resting semitendinosus rigidity. Independently of sex, the increase in resting hamstring muscles SWS with stretch was muscle specific.

Muscle B mode ultrasound and shear-wave elastography in idiopathic inflammatory myopathies (SWIM): criterion validation against MRI and muscle biopsy findings in an incident patient cohort

Background

B mode ultrasound (US) and shear wave elastography (SWE) are easily accessible imaging tools for idiopathic inflammatory myopathies (IIM) but require further validation against standard diagnostic procedures such as MRI and muscle biopsy.

Methods

In this prospective cross-sectional study we compared US findings to MRI and muscle biopsy findings in a group of 18 patients (11 F, 7 M) with active IIM (dermatomyositis 6, necrotising autoimmune myopathy 7, inclusion body myositis 4, overlap myositis 1) who had one or both procedures on the same muscle. US domains (echogenicity, fascial thickness, muscle bulk, shear wave speed and power doppler) in the deltoid and vastus lateralis were compared to MRI domains (muscle oedema, fatty infiltration/atrophy) and muscle biopsy findings (lymphocytic inflammation, myonecrosis, atrophy and fibro-fatty infiltration). A composite index score (1–4) was also used as an arbitrary indicator of overall muscle pathology in biopsies.

Results

Increased echogenicity correlated with the presence of fatty infiltration/atrophy on MRI (p = 0.047) in the vastus lateralis, and showed a non-significant association with muscle inflammation, myonecrosis, fibrosis and fatty infiltration/atrophy (p > 0.333) Severe echogenicity also had a non-significant association with higher composite biopsy index score in the vastus lateralis (p = 0.380). SWS and US measures of fascial thickness and muscle bulk showed poor discrimination in differentiating between pathologies on MRI or muscle biopsy. Power Doppler measures of vascularity correlated poorly with the presence of oedema on MRI, or with inflammation or fatty infiltration on biopsy. Overall, US was sensitive in detecting the presence of muscle pathology shown on MRI (67–100%) but showed poorer specificity (13–100%). Increased echogenicity showed good sensitivity when detecting muscle pathology (100%) but lacked specificity in differentiating muscle pathologies (0%). Most study participants rated US as the preferred imaging modality.

Conclusions

Our findings show that US, in particular muscle echogenicity, has a high sensitivity, but low specificity, for detecting muscle pathology in IIM. Traditional visual grading scores are not IIM-specific and require further modification and validation. Future studies should continue to focus on developing a feasible scoring system, which is reliable and allows translation to clinical practice.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41927-022-00276-w.

Lower Leg Muscle Stiffness on Two-Dimensional Shear Wave Elastography in Subjects With Medial Tibial Stress Syndrome

OBJECTIVES

We aimed to explore, which muscle stiffness changes may be related to medial tibial stress syndrome (MTSS) and the correlation between the medial tibial periosteal thickness and lower leg muscle stiffness.

METHODS

This study included 63 subjects distributed into 3 groups: the symptomless group, the MTSS group, and the control group. The lower leg muscle stiffness of the tibialis anterior (TA), extensor digitorum longus (EDL), peroneus longus (PL), soleus (SOL), lateral gastrocnemius (LG), medial gastrocnemius (MG), tibialis posterior (TP), and flexor digitorum longus (FDL) in the 3 groups was obtained by two-dimensional shear wave elastography. Differences in the muscle stiffness and medial tibial periosteal thickness in the 3 groups were determined by one-way analysis of variance (ANOVA) and least significant difference tests. The relationships between the periosteal thickness and the muscle stiffness were assessed using Pearson correlations.

RESULTS

The shear wave velocity (SWV) of all lower leg muscles except the EDL was higher in the symptomless and MTSS groups than in the control group (TA, P = .001; PL, P = .006; SOL, P < .001; LG, P < .001; MG, P < .001; TP, P < .001; FDL, P = .013; and ANOVA). A significant difference was found in the SWV of the SOL, TP, and FDL between the control and symptomless groups (P = .041, P < .001, and P = .013, respectively). Moreover, the medial tibial periosteum was thickened after running training, and its thickness was positively correlated with muscle stiffness.

CONCLUSION

The medial tibia periosteal thickness is positively correlated with the lower leg muscles stiffness. Changes in SOL, TP, and FDL stiffness may be related to the occurrence of MTSS.

A Preliminary Study to Assess the Relevance of Shear-Wave Elastography in Characterizing Biomechanical Changes in the Deltoid Ligament Complex in Relation to Ankle Position

BACKGROUND

The purpose of this study was (1) to evaluate the biomechanical properties of the different bundles of the deltoid ligament in various ankle positions in a cohort of healthy adult volunteers; (2) describe the impact of demographic and hindfoot morphology characteristics on their stiffness; (3) to assess the reliability and reproducibility of these measurements.

METHODS

Deltoid ligament complex of both ankles were assessed by shear-wave elastography (SWE) in 20 healthy patients resting on hinge support. The propagation shear-wave speed (SWS) in ligaments was measured, which is related to the tissue's elastic modulus. The following ligaments were analyzed in a neutral position and then in varus, valgus, dorsal, and plantar flexions: tibionavicular ligament (TNL), tibiocalcaneal ligament (TCL), the superficial posterior tibiotalar ligament (SPTL), the anterior tibiotalar ligament (ATTL), and the deep posterior tibiotalar ligament (DPTTL).

RESULTS

The mean SWS increased between neutral and 20 degrees valgus position for TCL (4.08 ± 0.78 m/s vs 5.56 ± 0.62 m/s, respectively; P < .0001) and for DPTTL (2.58 ± 0.52 m/s vs 3.59 ± 0.87 m/s, respectively; P < .0001). The mean SWS increased between neutral and 30 degrees plantarflexion for ATTL (2.11 ± 0.44 m/s vs 3.1 ± 0.5 m/s, respectively; P < .0001) and TNL (2.96 ± 0.66 m/s vs 4.99 ± 0.69 m/s, respectively; P < .0001). The mean SWS increased between neutral and 20 degrees dorsal flexion for SPTL (4.2 ± 1 m/s vs 5.45 ± 0.65 m/s, respectively; P < .0001).Women had less DPTTL SWS than men in the neutral position (2.37 ± 0.35 m/s vs 2.71 ± 0.49 m/s, respectively; P = .007). Other demographics had no impact on the SWS value of other ligaments. All inter- and intraobserver agreements were good to excellent.

CONCLUSION

This study presents a reliable and reproducible SWE measurement protocol to describe the physiological function of all bundles of the medial collateral ligament in healthy adults.

CLINICAL RELEVANCE

This examination technique can be available to orthopaedic surgeons, allowing reliable and reproducible monitoring of the SWS of the various ligaments constituting the medial collateral plane. The biomechanical values described in this study may give insight into in what position medial ankle ligament reconstruction should be tensioned.

Assessment of ultrasound shear wave elastography within muscles using different region of interest sizes, manufacturers, probes and acquisition angles: an ex vivo study

BACKGROUND

The application of shear wave elastography (SWE) in assessment of the musculoskeletal system is affected by various factors. This study aimed to explore the influence of machines, probes, region of interest (ROI) sizes, and the acquisition angles on muscle shear wave speed (SWS).

METHODS

The SWS of ex vivo isolated muscles were acquired using 3 different machines (Aixplorer system, SuperSonic Imagine; Acuson S3000, Siemens Healthcare; Resona 7, Mindray) and 2 linear probes (Aixplorer system, SL 10-2 and SL 15-4). Also, 4 different ROI sizes (diameter 1-10 mm) and 9 different acquisition angles (0-40°) were tested. The SWS acquired under different conditions were compared, and the intra-class correlation coefficients (ICC) were used to evaluate reproducibility.

RESULTS

There was a significant difference in SWS acquired using the 3 different machines (P<0.001) or with 9 different angles (P=0.008). There was no significant difference in SWS acquired using 2 probes (P=0.053) or 4 different ROI sizes (P=0.874, 0.778, and 0.865 for 3 operators, respectively). All machines produced substantial intra-system reproducibility (ICC, 0.61-0.80). Both probes demonstrated an almost perfect degree of intra-system agreement (ICC, >0.80), and nearly all ROI sizes demonstrated an almost perfect degree of intra- and inter-operator agreement (ICC, >0.80). The measurement reliability was higher when the acquisition angles were no more than 20°.

CONCLUSIONS

The 3 machines had different SWS values. Attention should be paid when comparing SWS results using different machines. For the Aixplorer system, the ROI size had no effect on the SWS values. Angles larger than 25° will lead to SWS measurements with greater variability compared to smaller angles (≤20°).

Is there a correlation between the femoral anteversion angle and the elasticity of the hip muscles in cases of intoeing gait due to increased femoral anteversion angle?

Purpose

One of the common causes of gait disturbance in children is increased femoral anteversion. There are not enough publications in the literature on muscles related to the hip joint in increased femoral anteversion. The aim of this study was to evaluate the relationship between the femoral anteversion angle and hip muscle elasticity in children walking inward, using shear wave elastography (SWE).

Material and methods

Seventeen children with bilateral increased femoral anteversion angle in computed tomography were prospectively included in this study. Elasticity values of the hip muscles (adductor magnus (adductor), iliopsoas (flexor), gluteus medius (abductor), gluteus maximus (extensor) muscles) were evaluated by ultrasound elastography by two observers. Quantitative measurements of the shear wave velocities were performed using virtual touch tissue imaging quantification.

Results

There was excellent harmony between the femoral anteversion angle measurements performed by the two observers and a good congruence between the muscle elastography evaluations. While there was a moderate significant correlation between the femoral anteversion angle and the elasticity values of the iliopsoas and adductor magnus muscles, no significant correlation was found with other muscle elasticity measurements.

Conclusion

Iliopsoas muscle and adductor magnus muscle elasticity are correlated with the femoral anteversion angle. With further studies, we think that physical therapy methods for the elasticity of the muscles associated with the femoral anteversion angle can reduce the complaints of the patients.

Full Characterization of in vivo Muscle as an Elastic, Incompressible, Transversely Isotropic Material Using Ultrasonic Rotational 3D Shear Wave Elasticity Imaging

Using a 3D rotational shear wave elasticity imaging (SWEI) setup, 3D shear wave data were acquired in the vastus lateralis of a healthy volunteer. The innate tilt between the transducer face and the muscle fibers results in the excitation of multiple shear wave modes, allowing for more complete characterization of muscle as an elastic, incompressible, transversely isotropic (ITI) material. The ability to measure both the shear vertical (SV) and shear horizontal (SH) wave speed allows for measurement of three independent parameters needed for full ITI material characterization: the longitudinal shear modulus μL , the transverse shear modulus μT , and the tensile anisotropy χE . Herein we develop and validate methodology to estimate these parameters and measure them in vivo, with μL = 5.77±1.00 kPa, μT = 1.93±0.41 kPa (giving shear anisotropy χμ = 2.11±0.92 ), and χE = 4.67±1.40 in a relaxed vastus lateralis muscle. We also demonstrate that 3D SWEI can be used to more accurately characterize muscle mechanical properties as compared to 2D SWEI.

Four weeks of exercise regimen for sedentary workers with rounded shoulder posture: a randomized controlled study

BACKGROUND

Rounded shoulder (RS) posture causes neck and shoulder pathologies. Mechanical correction taping (MCT) is often incorporated into postural corrective therapies; however, its effects on muscle stiffness are unclear.

OBJECTIVE

We investigated the effect of MCT with different tape fabrics, along with exercise, on upper trapezius and pectoralis minor muscle stiffness and the posture of sedentary workers.

DESIGN AND SETTING

A randomized controlled study was performed at Aydın Adnan Menderes University, Aydın, Turkey.

METHODS

The study included 39 workers with RS posture. Two intervention groups (performance tape: PT and classic tape: CT) were taped twice a week and administered a home exercise program for 4 weeks. The control (C) group performed only home exercises. RS was measured using an acromion-testing table (AT), stiffness using shear wave elastography ultrasound, and shoulder angle (SA) using a smartphone application at baseline and 4 weeks. Time and group interactions were determined using 3 × 2 mixed analysis of variance.

RESULTS

Intragroup analyses revealed a significant main effect of time on AT distance (η2 = 0.445) and SA (η2 = 0.325) in the PT and C groups (P < 0.05) and left upper trapezius stiffness (η2 = 0.287) in the CT and C groups (P < 0.05). In the post hoc analyses, no difference was noted between the groups from baseline to 4 weeks (P > 0.05).

CONCLUSION

Scapular MCT added to postural exercises did not show any difference between the intervention groups and controls in terms of muscle stiffness and posture in sedentary workers.

Limitations of Muscle Ultrasound Shear Wave Elastography for Clinical Routine-Positioning and Muscle Selection

Shear wave elastography (SWE) is a clinical ultrasound imaging modality that enables non-invasive estimation of tissue elasticity. However, various methodological factors—such as vendor-specific implementations of SWE, mechanical anisotropy of tissue, varying anatomical position of muscle and changes in elasticity due to passive muscle stretch—can confound muscle SWE measurements and increase their variability. A measurement protocol with a low variability of reference measurements in healthy subjects is desirable to facilitate diagnostic conclusions on an individual-patient level. Here, we present data from 52 healthy volunteers in the areas of: (1) Characterizing different limb and truncal muscles in terms of inter-subject variability of SWE measurements. Superficial muscles with little pennation, such as biceps brachii, exhibit the lowest variability whereas paravertebral muscles show the highest. (2) Comparing two protocols with different limb positioning in a trade-off between examination convenience and SWE measurement variability. Repositioning to achieve low passive extension of each muscle results in the lowest SWE variability. (3) Providing SWE shear wave velocity (SWV) reference values for a specific ultrasound machine/transducer setup (Canon Aplio i800, 18 MHz probe) for a number of muscles and two positioning protocols. We argue that methodological issues limit the current clinical applicability of muscle SWE.

Assessing the Effects of Aging on Muscle Stiffness Using Shear Wave Elastography and Myotonometer

The current study investigated the differences in muscle stiffness between older and young adults at rest and during contraction. We also evaluated the differences in muscle stiffness assessments using a myotonometer (MyotonPRO) and shear wave elastography (SWE). Twenty-two older adults (mean age, 66.6 ± 1.6 years) and 23 young adults (mean age, 66.6 ± 1.6 years) participated in this study. Muscle stiffness of the tibialis anterior (TA) and medial gastrocnemius (MG) muscles at rest and during contraction were measured using SWE and the MyotonPRO. The stiffness increase rate (SIR) was also calculated to determine the absolute stiffness difference. The mean muscle stiffness of the TA and MG muscles was significantly lower in older adults than in young adults at rest and during contraction (p < 0.05). Similarly, the SIR values of the TA and MG were significantly lower in older adults than in young adults (p < 0.05). Our results indicate that both instruments could be used to quantify muscle stiffness changes and serve as a cornerstone for assessing aging-related losses in muscle function. Stiffness measures may help exercise professionals to develop an in-depth understanding of muscle impairment at the tissue level.

Ultrasonic characterization of localized passive elastic properties of human pennate muscle with a single-probe setup

Quantitative evaluation of passive elastic properties of an individual skeletal muscle in vivo is among the major challenges of biomechanics, and its clinical application is severely limited. By combining shear-wave elastography (SWE) and B-mode imaging techniques, this study develops a novel non-invasive method to measure the local elastic modulus-fascicle strain curve of human pennation muscle during passive stretching using a single probe. Physiologically meaningful parameters are estimated and compared in subjects with different ages or pathological conditions. The in vivo experimental group comprised 12 healthy subjects (four children, four adults, and four seniors) and eight patients (four suffering from pseudohypertrophy, four from atrophy). Their gastrocnemius muscles were passively stretched using an ankle joint motion instrument. Local elastic moduli of the muscle were measured using SWE imaging frames and a built-in 'F-ROI' tool. The corresponding fascicle strains were simultaneously obtained using B-mode imaging frames and a gradient Radon transform. Three parameters (η, μ, G0) were estimated from a normalized elastic modulus-strain curve using the Gauss-Newton method. The measured elastic modulus-strain curves all agreed with models of the estimated parameters (0.910 < R2 < 0.999) and presented different patterns among normal and diseased subjects. η values were lower for pseudohypertrophies (1.93 ± 0.12), but higher for atrophies (63.40 ± 98.89), compared with normal ones (6.02 ± 2.53). In addition, μ values were higher for pseudohypertrophies (22.65 ± 16.40), but lower for atrophies (0.28 ± 0.41), compared with normal ones (1.07 ± 1.22). The proposed method may provide novel insight into the biomechanics of pennate muscle and has the potential to serve for clinical musculoskeletal medical diagnosis, as the single-probe scanning setup is broadly accepted.

Benefits of WALANT in palliative upper limb surgery after nerve injury

Wide-Awake Local Anesthesia No Tourniquet (WALANT) may be a satisfactory anesthesia alternative for the management of upper limb peripheral nerve palsy sequelae. The main advantages are the possibility of active patient cooperation through intraoperative active mobilization, comfort and cost reduction. The legislation about WALANT in France remains unclear; the modalities of lidocaine epinephrine injection should be redefined. For palliative upper limb surgery, WALANT allows the surgeon to adjust the tension on the tendon transfer intraoperatively. Level 1 studies are needed to evaluate the effectiveness of WALANT relative to standard anesthesia techniques (regional/general anesthesia).

Effect of Resonant Frequency Vibration on Delayed Onset Muscle Soreness and Resulting Stiffness as Measured by Shear-Wave Elastography

This study utilized resonant frequency vibration to the upper body to determine changes in pain, stiffness and isometric strength of the biceps brachii after eccentric damage. Thirty-one participants without recent resistance training were randomized into three groups: a Control (C) group and two eccentric exercise groups (No vibration (NV) and Vibration (V)). After muscle damage, participants in the V group received upper body vibration (UBV) therapy for 5 min on days 1-4. All participants completed a visual analog scale (VAS), maximum voluntary isometric contraction (MVIC), and shear wave elastography (SWE) of the bicep at baseline (pre-exercise), 24 h, 48 h, and 1-week post exercise. There was a significant difference between V and NV at 24 h for VAS (p = 0.0051), at 24 h and 1-week for MVIC (p = 0.0017 and p = 0.0016, respectively). There was a significant decrease in SWE for the V group from 24-48 h (p = 0.0003), while there was no significant change in the NV group (p = 0.9341). The use of UBV resonant vibration decreased MVIC decrement and reduced VAS pain ratings at 24 h post eccentric damage. SWE was strongly negatively correlated with MVIC and may function as a predictor of intrinsic muscle state in the time course of recovery of the biceps brachii.

Feasibility of Rib Kinematics and Intercostal-Space Biomechanical Characterization by Ultrasound in Adolescent Idiopathic Scoliosis

The aim of this work was to determine the feasibility of combined ultrasonography and elastography measurement to characterize the mechanical properties of the intercostal space during breathing. Eighteen asymptomatic participants (ages 13 ± 2 y) and six participants with adolescent idiopathic scoliosis (AIS) were included (Cobb angle 60° ± 12°). Ultrasonographic and elastographic clips were acquired of T8-T9 ribs and the intercostal space. The two adjacent ribs were tracked to infer the breathing cycle. Shear-wave speed (SWS) was measured in the intercostal space at different stages of the breathing cycle. SWS was symmetric in the control group, during both expiration and inspiration. In AIS, the SWS during inspiration was higher in the convex side than in the concave one (p = 0.02). Furthermore, SWS was higher during inspiration than expiration in the control group and in the AIS convex side, but not in the AIS concave side (p > 0.05). This new method combining echography and shear-wave elastography allowed measurement of the mechanical characteristics of the intercostal space at different phases of the breathing cycle and highlighted differences between the AIS and control groups. This approach opens the way to further analyses of the biomechanical characteristics of breathing in severe AIS.

Muscle elasticity in patients with neonatal brachial plexus palsy using shear-wave ultrasound elastography. Preliminary results

Ultrasound shear wave elastography (SWE) is a noninvasive, reliable and reproducible method, used for the qualitative and quantitative evaluation of tissues. The aim of this study was to compare muscle elasticity between the healthy and the involved sides in children with neonatal brachial plexus palsy (NBPP) using the elastography tool and to assess whether the difference was correlated with the Mallet grading system. We repeatedly measured the shear modulus coefficient of several muscles around the shoulder in stretched or passively relaxed positions on 14 patients. We evaluated the abductor muscles (supraspinatus and deltoid), the infraspinatus, the pectoralis major and the latissimus dorsi. We found a mean shear modulus significantly higher in most studied muscles in the pathologic side (P < 0.001), especially in the stretched position (P < 0.001). Moreover, the shear modulus increases with the degradation of the Mallet score for the abduction and external rotation tasks. SWE seems to be a reliable and reproducible tool to assess muscle elasticity in NBPP.

Quantitative assessment of normal middle deltoid muscle elasticity at various arm abduction using ultrasound shear wave elastography

The objective of this study is to assess the change in the normal MD elasticity using shear wave elastography (SWE) through measuring the middle deltoid (MD) elasticity in healthy participants at various arm abduction (with bilateral arms at 0 degrees abduction and 90 degrees active abduction) and analyzing the factors affecting normal MD elasticity. Mean shear wave velocity (SWV) of the MD in healthy right-handed participants were evaluated using SWE at different arm abduction, and potential factors (gender, MD thickness, age, body mass index) affecting MD elasticity were analyzed. Different arm abduction positions of each participant were as follows: (i) 0° abduction of bilateral arm (L0° and R0°), (ii) 90° active abduction of bilateral arm (L90° and R90°). Mean SWV was significantly higher at L90° than L0°, higher at R90° than R0°, higher at R0° than L0°, and higher at R90° than L90° (all P < 0.0001). SWV was significantly higher in males at both L0° (P < 0.05) and R0° (P < 0.01) than in females. Neither MD thickness, age nor body mass index influenced MD elasticity. Reference ranges of normal MD elasticity were 2.4–3.1 m/s in males and 2.2–2.9 m/s in females at L0° and 2.5–3.3 m/s in males and 2.4–3.2 m/s in females at R0°, and were 4.9–6.7 m/s at L90°, 5.2–7.1 m/s at R90° for both males and females. SWE is a feasible technique to assess normal MD elasticity at various arm abduction. Our results suggest that normal MD elasticity at L0°, R0°, L90°, and R90° with SWE are different. Moreover, these reference ranges may serve as quantitative baseline measurements for assessment of normal MD elasticity in the future.