Ultrasound elastography in neuromuscular and movement disorders

Understanding tightened muscle in knee osteoarthritis and the impacts of Fu's subcutaneous needling: A pilot trial with shear-wave elastography and near-infrared spectroscopy

BACKGROUND

Given the scarce reports on the interplay between Fu's subcutaneous needling (FSN), tightened muscle, and therapeutic effects, we developed a clinical research protocol to synchronously collect data on clinical efficacy and muscle characteristics in patients with knee osteoarthritis, exploring the mechanism of FSN action. The primary aim was to assess the feasibility and safety of this protocol, guiding future trials and their sample size calculations.

METHODS

In this prospective, single-blind, self-controlled study, 19 patients with early to mid-stage unilateral knee osteoarthritis underwent FSN therapy on both knees over 1 week (4 sessions, every other day). We measured local elastic modulus, muscle thickness, blood flow volume, and oxygen consumption rate of bilateral vastus lateralis muscles using shear-wave elastography and near-infrared spectroscopy (NIRS) before and after the first and fourth treatments. Additionally, real-time NIRS indicators (oxygenated hemoglobin [O2Hb], deoxyhemoglobin [HHb], total hemoglobin [THb], and tissue saturation index [TSI]) were recorded during these treatments. Pain intensity (visual analogue scale [VAS]), functional status (Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC]), and active range of motion were evaluated before these treatments.

RESULTS

All 19 participants completed the trial without serious adverse events. After 3 FSN treatments, significant changes were observed in VAS and WOMAC scores (VAS: P < .001; WOMAC: P < .001), and knee flexion (P < .001) and external rotation (P = .02), except for internal rotation. No meaningful significant differences were observed in muscle characteristics at baseline or between pre- and post-treatment periods. NIRS results during treatments indicated significant increases in local O2Hb and THb post-FSN therapy (First treatment: O2Hb: P = .005; THb: P = .006. Fourth treatment: O2Hb: P = .002; THb: P = .004); however, no significant increases were observed for HHb (First treatment: P = .06; Fourth treatment: P = .28). No linear correlation was found between therapeutic effects and changes in tightened muscle indices.

CONCLUSION

FSN reduces pain and improves joint function in knee osteoarthritis, while also enhancing blood flow and oxygenation in the vastus lateralis muscle of the affected side. Further revisions of this protocol are warranted based on our insights.

Evidence of spinal stiffening following fusionless bipolar fixation for neuromuscular scoliosis: a shear wave elastography assessment of lumbar annulus fibrosus

OBJECTIVES

There are no established criteria for stiffness after fusionless surgery for neuromuscular scoliosis (NMS). As a result, there is no consensus regarding the surgical strategy to propose at long-term follow-up. This study reports the first use of shear wave elastography for assessing the mechanical response of lumbar intervertebral discs (IVDs) after fusionless bipolar fixation (FBF) for NMS and compares them with healthy controls. The aim was to acquire evidence from the stiffness of the spine following FBF.

PATIENTS AND METHODS

Nineteen NMS operated on with FBF (18 ± 2y at last follow-up, 6 ± 1 y after surgery) were included prospectively. Preoperative Cobb was 89 ± 20° and 35 ± 1° at latest follow-up. All patients had reached skeletal maturity. Eighteen healthy patients (20 ± 4 y) were also included. Shear wave speed (SWS) was measured in the annulus fibrosus of L3L4, L4L5 and L5S1 IVDs and compared between the two groups. A measurement reliability was performed.

RESULTS

In healthy subjects, average SWS (all disc levels pooled) was 7.5 ± 2.6 m/s. In NMS patients, SWS was significantly higher at 9.9 ± 1.4 m/s (p < 0.05). Differences were significant between L3L4 (9.3 ± 1.8 m/s vs. 7.0 ± 2.5 m/s, p = 0.004) and L4L5 (10.3 ± 2.3 m/s vs. 7.1 ± 1.1 m/s, p = 0.0006). No difference was observed for L5S1 (p = 0.2). No correlation was found with age at surgery, Cobb angle correction and age at the SWE measurement.

CONCLUSIONS

This study shows a significant increase in disc stiffness at the end of growth for NMS patients treated by FBF. These findings are a useful adjunct to CT-scan in assessing stiffness of the spine allowing the avoidance of surgical final fusion at skeletal maturity.

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.

Quantitative assessment of spasticity: a narrative review of novel approaches and technologies

Spasticity is a complex neurological disorder, causing significant physical disabilities and affecting patients' independence and quality of daily lives. Current spasticity assessment methods are questioned for their non-standardized measurement protocols, limited reliabilities, and capabilities in distinguishing neuron or non-neuron factors in upper motor neuron lesion. A series of new approaches are developed for improving the effectiveness of current clinical used spasticity assessment methods with the developing technology in biosensors, robotics, medical imaging, biomechanics, telemedicine, and artificial intelligence. We investigated the reliabilities and effectiveness of current spasticity measures employed in clinical environments and the newly developed approaches, published from 2016 to date, which have the potential to be used in clinical environments. The new spasticity scales, taking advantage of quantified information such as torque, or echo intensity, the velocity-dependent feature and patients' self-reported information, grade spasticity semi-quantitatively, have competitive or better reliability than previous spasticity scales. Medical imaging technologies, including near-infrared spectroscopy, magnetic resonance imaging, ultrasound and thermography, can measure muscle hemodynamics and metabolism, muscle tissue properties, or temperature of tissue. Medical imaging-based methods are feasible to provide quantitative information in assessing and monitoring muscle spasticity. Portable devices, robotic based equipment or myotonometry, using information from angular, inertial, torque or surface EMG sensors, can quantify spasticity with the help of machine learning algorithms. However, spasticity measures using those devices are normally not physiological sound. Repetitive peripheral magnetic stimulation can assess patients with severe spasticity, which lost voluntary contractions. Neuromusculoskeletal modeling evaluates the neural and non-neural properties and may gain insights into the underlying pathology of spasticity muscles. Telemedicine technology enables outpatient spasticity assessment. The newly developed spasticity methods aim to standardize experimental protocols and outcome measures and enable quantified, accurate, and intelligent assessment. However, more work is needed to investigate and improve the effectiveness and accuracy of spasticity assessment.

Validity and reliability of the assessment of hand flexors stiffness using a new electromechanical oscillatory device in people with stroke

Hyper-resistance after a central nervous system injury has been largely referred to as spasticity, which is but one of its neural components. Assessment largely relies on clinical scales (Modified Ashworth scale - MAS and Modified Tardieu scale, MTS) which are unable to distinguish between the non-neural (tissue-related) and the neural (central nervous system-related) components. This study assessed criterion validity and reliability (reproducibility) of muscle stiffness measures, namely, maximum elastic stiffness (ELmax), viscous stiffness (VI), and path length (L-path) in the hand flexor muscles among people with stroke. Measurements were obtained with a wrist-electromechanical oscillatory device (w-EOD). Twenty-four people with arm impairment after stroke were evaluated with the w-EOD and clinical assessment (MAS and MTS), twice on the same day (short-term reliability) and once 10 days later (long-term reliability). For criterion validity, a Spearman coefficient ( r ) was calculated between stiffness values and the clinical scales. For reliability, intraclass correlation coefficients (ICCs), SEM, and MDC95 were calculated. Moderate correlations were observed between EL max and MAS ( r  = 0.49) and MTS (V2, r  = 0.43; V3, r  = 0.49) of the wrist flexors, and finger flexors (MAS, r  = 0.60; MTS V2, r  = 0.56; MTS V3, r  = 0.55). There was a poor correlation between the clinical scales and VI and L-path. Reliability was excellent for all stiffness measurements at short term (EL max : 0.95, VI: 0.94, L-path: 0.92) and good at long term (EL max : 0.87, VI: 0.76, L-path: 0.82). In conclusion, stiffness measurements are valid and reliable to evaluate hyper-resistance in people with stroke.

The Utility of Myotonometry in Musculoskeletal Rehabilitation and Human Performance Programming

Myotonometry is a relatively novel method used to quantify the biomechanical and viscoelastic properties (stiffness, compliance, tone, elasticity, creep, and mechanical relaxation) of palpable musculotendinous structures with portable mechanical devices called myotonometers. Myotonometers obtain these measures by recording the magnitude of radial tissue deformation that occurs in response to the amount of force that is perpendicularly applied to the tissue through a device's probe. Myotonometric parameters such as stiffness and compliance have repeatedly demonstrated strong correlations with force production and muscle activation. Paradoxically, individual muscle stiffness measures have been associated with both superior athletic performance and a higher incidence of injury. This indicates optimal stiffness levels may promote athletic performance, whereas too much or too little may lead to an increased risk of injury. Authors of numerous studies suggested that myotonometry may assist practitioners in the development of performance and rehabilitation programs that improve athletic performance, mitigate injury risk, guide therapeutic interventions, and optimize return-to-activity decision-making. Thus, the purpose of our narrative review was to summarize the potential utility of myotonometry as a clinical tool that assists musculoskeletal clinicians with the diagnosis, rehabilitation, and prevention of athletic injuries.

Relationship between motor performance and cortical activity of older neurological disorder patients with dyskinesia using fNIRS: A systematic review

Background: Neurological disorders with dyskinesia would seriously affect older people’s daily activities, which is not only associated with the degeneration or injury of the musculoskeletal or the nervous system but also associated with complex linkage between them. This study aims to review the relationship between motor performance and cortical activity of typical older neurological disorder patients with dyskinesia during walking and balance tasks.

Methods: Scopus, PubMed, and Web of Science databases were searched. Articles that described gait or balance performance and cortical activity of older Parkinson’s disease (PD), multiple sclerosis, and stroke patients using functional near-infrared spectroscopy were screened by the reviewers. A total of 23 full-text articles were included for review, following an initial yield of 377 studies.

Results: Participants were mostly PD patients, the prefrontal cortex was the favorite region of interest, and walking was the most popular test motor task, interventional studies were four. Seven studies used statistical methods to interpret the relationship between motor performance and cortical activation. The motor performance and cortical activation were simultaneously affected under difficult walking and balance task conditions. The concurrent changes of motor performance and cortical activation in reviewed studies contained the same direction change and different direction change.

Conclusion: Most of the reviewed studies reported poor motor performance and increased cortical activation of PD, stroke and multiple sclerosis older patients. The external motor performance such as step speed were analyzed only. The design and results were not comprehensive and profound. More than 5 weeks walking training or physiotherapy can contribute to motor function promotion as well as cortices activation of PD and stroke patients. Thus, further study is needed for more statistical analysis on the relationship between motor performance and activation of the motor-related cortex. More different type and program sports training intervention studies are needed to perform.

Characterization of Muscle Weakness Due to Myasthenia Gravis Using Shear Wave Elastography

Myasthenia gravis (MG) is often accompanied with muscle weakness; however, little is known about mechanical adaptions of the affected muscles. As the latter can be assessed using ultrasound shear wave elastography (SWE), this study characterizes the biceps brachii muscle of 11 patients with MG and compares them with that of 14 healthy volunteers. Simultaneous SWE, elbow torque and surface electromyography measurements were performed during rest, maximal voluntary contraction (MVC) and submaximal isometric contractions (up to 25%, 50% and 75% MVC) at different elbow angles from flexion to extension. We found that, with increasing elbow angle, maximum elbow torque decreased (p < 0.001), whereas muscle stiffness increased during rest (p = 0.001), MVC (p = 0.004) and submaximal contractions (p < 0.001). Muscle stiffness increased with increasing contraction intensities during submaximal contractions (p < 0.001). In comparison to the healthy cohort, muscle stiffness of MG patients was 2.1 times higher at rest (p < 0.001) but 8.93% lower in active state (75% MVC, p = 0.044). We conclude that (i) increased muscle stiffness shown by SWE during rest might be an indicator of MG, (ii) SWE reflects muscle weakness and (iii) SWE can be used to characterize MG muscle.

Ultrasound and elastography role in pre- and post-operative evaluation of median neuropathy in patients with carpal tunnel syndrome

Introduction

Carpal tunnel syndrome (CTS) is a common compression neuropathy of the median nerve in the wrist. Early diagnosis of CTS is essential for selecting treatment options and assessing prognosis. The current diagnosis of CTS is based on the patient's clinical symptoms, signs, and an electromyography (EMG) test. However, they have some limitations. Recently, ultrasound has been adopted as an adjunct diagnostic tool for electromyography (EMG). Ultrasound is a non-invasive and cost-effective technique. It provides a dynamic display of morphological changes in the median nerve and an assessment of CTS etiology such as tenosynovitis, mass compression, and tendon disease. This study aimed to investigate the value of conventional ultrasound and real-time shear wave elastography (SWE) in evaluation of median neuropathy in patients with carpal tunnel syndrome (CTS) before and after surgery.

Methods

First, the Boston Carpal Tunnel Questionnaire (BCTQ) was administered to patients with CTS. All subjects were measured at three levels: the distal 1/3 of the forearm, the carpal tunnel inlet, and the distal carpal tunnel using conventional ultrasound and SWE. Median nerve parameters were examined in patients with CTS 1 week after surgery.

Results

The cross-sectional area (CSA) and stiffness of the median nerve at the carpal tunnel inlet and distal carpal tunnel were significantly higher in patients with CTS than in healthy controls (p < 0.001). The CSA and stiffness of the median nerve at the carpal tunnel inlet were statistically significantly significantly between pre- and postoperative patients with CTS (p < 0.001). The CSA and stiffness of the nerve in patients with CTS had a positive correlation with electrophysiology severity.

Conclusions and discussion

Conventional ultrasound and elastography are valuable in the diagnosis of CTS and are useful in the clinical assessment of patient's nerve recovery after operation.

Diagnostic value of shear wave ultrasound elastography of tibial nerve in patients with diabetic peripheral neuropathy

Background

Diabetic peripheral neuropathy (DPN) is a major complication of Diabetes mellitus. So this study aimed at investigation of the value of tibial nerve stiffness measured by shear wave ultrasound elastography (SWE) for detection of DPN. This case–control study involved 50 patients with DPN, 50 patients with diabetes mellitus but without DPN, and 50 healthy controls. Clinical examination, nerve conduction study of both tibial nerves, high resolution ultrasound and SWE to assess cross sectional area "CSA" of tibial nerves, and tibial nerves mean stiffness, respectively. ROC curve analysis was also performed.

Results

Mean tibial nerve stiffness by SWE was higher in patients with DPN compared to other groups (P value < 0.001). The CSA of the tibial nerve in the DPN group was significantly larger than that in the other groups (P value = 0.01). The cutoff value by ROC curve analysis for tibial nerve stiffness to differentiate patients with DPN and control group was 70.6 kPa (P value < 0.001, 95.4% sensitivity, 94.7% specificity, AUC = 0.963), while 86.5 kPa was the optimal cutoff point to differentiate patients with DPN and other groups with a 94.6% sensitivity, 93.8% specificity, AUC of 0.975 and P value < 0.001. Higher diagnostic accuracy was found when combination of SWE and high resolution US (high resolution US + shear wave; 0.987, P value < 0.001).

Conclusions

Tibial nerve stiffness was increased in patients with DPN. SWE can be used as an effective complementary method in diagnosis of DPN with high sensitivity and accuracy.

A scoping review of methods used in musculoskeletal soft tissue and nerve shear wave elastography studies

This scoping review of shear wave elastography (SWE) articles in musculoskeletal soft tissue and nerve research demonstrates methodological heterogeneity resulting from a lack of standardized data collection and reporting requirements. Seven literature databases were searched for original articles published in English from 2004-2020 that examine human skeletal muscles, tendons, and nerves in vivo. Although 5,868 records were initially identified, only 375 reports met inclusion criteria. Of the 375 articles, 260 examined 89 unique muscles, 94 examined 14 unique tendons, and 43 examined 8 unique nerves. Cohorts were often small (n = 11-20) and young (mean = 20-29 years), and participants were typically tested in the prone position. Regarding equipment, a variety of ultrasound systems (n = 11), ultrasound models (n = 18), and transducers (n = 19) were identified. Only 11% of articles contained information on the use of electromyography to confirm absence of muscle activity, and only 8% reported measurement depth. Since musculoskeletal soft tissue and nerve stiffness can vary significantly based on data collection methods, it is essential to standardize SWE collection and reporting procedures. This will allow SWE to serve as a valid and reproducible tool for assessing tissue pathology, disease progression, and response to intervention within a variety of musculoskeletal and nerve-related disorders.

Self-Enhanced Acoustic Impedance Difference Strategy for Detecting the Acidic Tumor Microenvironment

B-mode ultrasound imaging is a significant anatomic technique in clinic, which can display the anatomic variation in tissues. However, it is difficult to evaluate the functional state of organs and display the physiological information in organisms such as the tumor acidic microenvironment (TME). Herein, inspired by the phenomenon of sonographic acoustic shadow during detecting calculus in clinic, a strategy of self-enhanced acoustic impedance difference is proposed to monitor the acidic TME. BiF₃@PDA@PEG (BPP) nanoparticles can self-aggregate in a specific response to the acidic TME to form huge "stones" BiF₃@PDA, resulting in an increase of local tumor density, and further causing a significant acoustic impedance difference. In in vitro experiments, the enhanced ultrasound signals change from 15.2 to 196.4 dB, which can discriminate different pH values from 7.0 to 5.0, and the sensitivity can reach to 0.2 value. In in vivo experiments, the enhanced ultrasound signal is 107.7 dB after BPP self-aggregated, displaying the weak acidic TME that has a close relationship with the size and species of the tumor. More importantly, the accuracy is away from the interference of pressure because huge "stones" BiF₃@PDA change little. However, SonoVue microbubbles will diffuse and rupture under pressure, which results in false positive signals. To sum up, this strategy will be helpful to the further development of ultrasound molecular imaging.

Diagnostic value of median nerve shear wave ultrasound elastography in diagnosis and differentiation of carpal tunnel syndrome severity

Background

Carpal tunnel syndrome (CTS) is the commonest type of peripheral nerve entrapment syndromes. The study aimed at evaluation of diagnostic value of median nerve stiffness measured by shear wave ultrasound elastography for diagnosis and differentiation of CTS severity, correlated to electrophysiological studies. This case–control study involved 40 patients (56 wrists) with CTS of different severity and 40 controls (40 wrists). All participants underwent electrophysiological study to assess the CTS severity, high-resolution conventional B-mode ultrasound to assess cross-sectional area “CSA” of median nerve at carpal tunnel, ratio of median nerve CSA at carpal tunnel and forearm, and shear wave ultrasound elastography with measurement of median nerve mean stiffness and correlation to electrophysiological results as the reference standard.

Results

Mean median nerve stiffness by shear wave US elastography was increased in patients with CTS compared to controls and across the different CTS severity groups (P value < 0.001 & 0.001, respectively). The cutoff value by ROC curve analysis for median nerve stiffness to differentiate between patients with CTS and control group was 65.4 kPa (P value < 0.001, 94.6% sensitivity, 97.3% specificity). Higher diagnostic accuracy was noted with the combination of shear wave elastography and conventional B-mode US with improved AUC (B-mode + shear wave; 0.962, P value < 0.001).

Conclusions

Shear wave ultrasound elastography of median nerve was able to discriminate different severity subgroups of CTS with high sensitivity, while conventional US couldn’t. The diagnostic accuracy of CTS was improved when combined high-resolution conventional B-mode US and complementary shear wave ultrasound elastography.

The Utility of Shear-Wave Elastography in the Evaluation of Myositis

Changes in muscle elasticity are expected in patients with untreated myositis. The purpose of this study was to define the accuracy of shear-wave elastography (SWE) in diagnosing myositis. This case control study included 21 patients (mean age, 49.4 y; 12 women) with myositis who underwent SWE, magnetic resonance imaging (MRI) and biopsy of the involved muscle group. SWE was performed accordingly in a control group (n = 24; mean age, 51.2 y; 8 women). Blood tests consisted of creatine kinase (CK) and aldolase. Two operators performed SWE in longitudinal and transverse planes of muscular fibers, quantifying the mean shear-wave velocity (SWV) and the pattern of stiffness. On MRI, short-TI inversion recovery (STIR) signal hyperintensity and T1 contrast enhancement of muscle was considered diagnostic for myositis. The patient group suffered from different types of myositis (nine patients with polymyositis, eight with dermatomyositis and four with other types of myositis). Blood tests showed significantly increased CK and aldolase values in patients with myositis (p < 0.001 and p < 0.0001). MRI showed a sensitivity of 0.95. In the patient group, the mean SWVs of longitudinal and transverse measurements were 2.8 ± 1.4 m/s and 3.1 ± 1.2 m/s, respectively. In the control group, SWVs were 2.3 ± 0.5 m/s and 2.4 ± 0.5 m/s, respectively. The difference between transverse measurements was significant (p = 0.02). Increased heterogeneity as a marker for myositis in transverse SWE showed a sensitivity of 0.8, specificity of 0.79, positive predictive value (PPV) of 0.76 and negative predictive value (NPV) of 0.82. Inter-observer difference was very low (κ = 0.92). Increased heterogeneity in both planes compared with histologic results showed a sensitivity of 0.56, specificity of 0.93, PPV of 0.91 and NPV of 0.62. Spearman correlation between CK <1000 U/L and SWE was 0.54. In conclusion, transverse orientation SWE may serve as an imaging biomarker for the diagnosis of myositis through the display of a heterogeneous pattern and increased absolute SWV values of inflamed muscles.

Ultrasound Elastography in the Assessment of the Stiffness of Spastic Muscles: A Systematic Review

The incidence of muscle spasticity is high in patients with diseases of the central nervous system. This condition leads to significant limitations in movement and impaired functional capacities. Muscle spasticity manifests as changes in the mechanical properties of the muscles. This muscle disorder is generally assessed using qualitative methods, whose validity, reliability and sensitivity are questionable. In recent years, ultrasound elastography (USE) has been used as a non-invasive technique for characterizing the stress response and mechanical properties of individual muscles in the evaluation of spasticity. This article presents a systematic review of the USE techniques, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) declaration guidelines, used for the evaluation of muscle stiffness caused by spasticity. The articles selected in this study were evaluated using the Quality Appraisal of Diagnostic Reliability (QAREL) tool. Mainly, studies on the assessment of spasticity involving the evaluation of muscle stiffness with USE techniques (i.e., shear-wave elastography [SWE] or compression elastography [CE]) were selected. Then, common topics related to the assessment of spastic muscles and the statistical results of these studies were classified. Of 21 articles, nine used only CE, 10 used only SWE and two used both techniques. In the studies, statistically significant differences were observed in the measurements of muscle stiffness between the paretic and non-paretic sides as well as between patients and healthy patients. The clinical measurements obtained, devices used and assessment and probe positions for both techniques were discussed. The most frequently studied muscles were the biceps (n = 7) and gastrocnemius (n = 11). On applying the QAREL tool, we found that only two studies showed compliance at 80%-90%, seven studies at 50%-70% and the remaining 12 at 10%-40%. The results showed that USE techniques have limitations in spasticity assessment, such as subjectivity because of the lack of standardized protocols. A deficit of studies on intra-operator and inter-operator measurements indicates that this technique is not yet mature for spasticity diagnosis, although it is a promising diagnostic tool for designing treatment plans and monitoring the effectiveness of therapeutic modalities.

Quantitative Ultrasound to Assess Skeletal Muscles in Post Stroke Spasticity

Quantitative ultrasound (QUS) techniques such as pixel intensity, ultrasound strain, and shear wave elastography have made it possible to identify the echogenicity (brightness) and mechanical properties (stiffness) of normal and pathological tissues. These techniques can be utilized as an alternative diagnosis tool to assess post stroke spasticity. Current clinical assessment methods include the Modified Ashworth Scale (MAS) and the Modified Tardieu Scale (MTS), which can result in inconsistencies due to their subjective nature. QUS provides robust approaches to assessing muscle stiffness associated with post stroke spasticity. Computer-aided pixel count quantifies tissue echogenicity in grayscale image. A strain ratio in ultrasound strain imaging compares the stiffness and movement (lengthening or shortening) of a spastic muscle with nonspecific muscle. In addition, shear wave elastography provides the shear wave velocity of an affected muscle that directly associated with the muscle stiffness before and after treatment for spasticity. This article reviews the theory behind these aforementioned concepts and discuss the relations between QUS and skeletal muscles in post stroke spasticity.

Shearwave Elastography in the Differentiation of Carpal Tunnel Syndrome Severity

BACKGROUND

There is emerging evidence that ultrasound elastography may provide additional diagnostic information in peripheral neuropathies.

OBJECTIVE

To investigate the use of ultrasound elastography to evaluate median nerve stiffness in patients with carpal tunnel syndrome (CTS), as well as the relationship between the elastographic stiffness and electrophysiological severity.

DESIGN

Case control study.

SETTING

Tertiary hospital outpatient neurophysiology clinic.

PARTICIPANTS

Twenty eight patients (47 wrists) with CTS and 25 control patients (25 wrists).

INTERVENTIONS

None.

MAIN OUTCOME MEAURES

Ultrasound parameters (median nerve cross-sectional area [CSA] at carpal tunnel, ratio of median nerve CSA at carpal tunnel and forearm), shearwave elastography parameter (median nerve stiffness), and electrophysiological severity of carpal tunnel syndrome.

RESULTS

In patients with CTS, median nerve stiffness by ultrasound elastography was increased between the different severity groups (control 83.5 ± 24.8, EDx negative CTS 84.2 ± 46.4, mild 117.7 ± 79.3, moderate 144.0 ± 71.1, severe 196.6 ± 48.4). The control versus moderate and severe subgroup was statistically significant.

CONCLUSIONS

In total, this study has demonstrated that ultrasound elastography was able to discriminate the severity of CTS whereas conventional ultrasound parameters did not.

Ultrasound elastography for the evaluation of peripheral nerves: A systematic review

Peripheral nerve disorders are commonly encountered in clinical practice. Electrodiagnostic studies remain the cornerstone of the evaluation of nerve disorders. More recently, ultrasound has played an increasing complementary role in the neuromuscular clinic. Ultrasound elastography is a technique that measures the elastic properties of tissues. Given the histological changes that occur in diseased peripheral nerves, nerve ultrasound elastography has been explored as a noninvasive way to evaluate changes in nerve tissue composition. Studies to date suggest that nerve stiffness tends to increase in the setting of peripheral neuropathy, regardless of etiology, consistent with loss of more compliant myelin, and replacement with connective tissue. The aim of this systematic review is to summarize the current literature on the use of ultrasound elastography in the evaluation of peripheral neuropathy. Limitations of ultrasound elastography and gaps in current literature are discussed, and prospects for future clinical and research applications are raised.

Quantifying cervical and axioscapular muscle stiffness using shear wave elastography

This study aimed to assess intra-rater (intra-session and inter-day) reliability and influence of side dominance and the scapular resting position on the shear modulus (an index of stiffness) of resting cervical and axioscapular muscles. Sixteen healthy participants were recruited. On day one, ultrasound shear wave elastography was used to measure the shear modulus of superficial and deep cervical extensor and axioscapular muscles bilaterally. Clinical assessments of scapular resting position were performed bilaterally. On day two, testing was repeated on the dominant side. Both intra-session and inter-day reliability were good to excellent for shear modulus of superficial muscles, and poor to excellent for deep muscles. Side differences of shear modulus for posterior upper trapezius were statistically significant but clinically irrelevant. The shear modulus of posterior upper trapezius and middle trapezius were significantly correlated with scapular depression. Ultrasound shear wave elastography is a reliable tool for quantitatively assessing stiffness of superficial cervical and axioscapular muscles. The influence of scapular position should be considered in future comparative studies of healthy controls and patients with neck/shoulder pain. This study provides the necessary first step for future studies on assessing and interpreting the stiffness of cervical and axioscapular muscles for neck and shoulder musculoskeletal disorders.