Ability of magnetic resonance elastography to assess taut bands

Feasibility study of the application of magnetic resonance elastography (MRE) to measure oral posture related changes in stiffness of zygomaticus major muscle

PURPOSE

Development of a technique for measuring the mechanical properties of zygomaticus major (ZM) may aid advances in clinical treatments for correcting abnormal oral posture. The objective of this work was to demonstrate the feasibility of measuring the stiffness of ZM using an MR elastography technique that incorporates a custom local driver and a phase-gradient (PG) inversion.

METHODS

2D MRE investigations were performed for 3 healthy subjects using a vibration frequency of 90 Hz to test the prediction that the stiffness of ZM would be greater in the mouth-open compared to the mouth-closed position. MRE wave images were acquired along the long axis of ZM and processed using a 2D spatial-temporal directional filter applied in the direction of wave propagation along the long axis of the muscle. Stiffness measurements were obtained by applying the PG technique to a 1D-profile drawn in the phase image of the first harmonic of the wave images and a one-tailed paired t-test was used to compare the ZM stiffness between the two mouth postures (p < 0.05).

RESULTS

The mean stiffness and standard deviation (SD) of ZM across the three participants in the mouth-closed and mouth-open postures was 6.75 kPa (SD 3.36 kPa) and 15.5 kPa (SD 5.15 kPa), respectively. Changes of ZM stiffness were significantly greater in the mouth-open than the mouth-closed posture (p = 0.038).

CONCLUSION

The feasibility of using the PG MRE technique to measure stiffness changes in a small muscle such as ZM for different mouth postures has been demonstrated. Further investigations are required in a larger cohort of participants to investigate the sensitivity and reproducibility of the technique for potential clinical application as well as in health and beauty related studies.

MR elastography-based slip interface imaging (SII) for functional assessment of myofascial interfaces: A feasibility study

PURPOSE

Abnormal adherence at functional myofascial interfaces is hypothesized as an important phenomenon in myofascial pain syndrome. This study aimed to investigate the feasibility of MR elastography (MRE)-based slip interface imaging (SII) to visualize and assess myofascial mobility in healthy volunteers.

METHODS

SII was used to assess local shear strain at functional myofascial interfaces in the flexor digitorum profundus (FDP) and thighs. In the FDP, MRE was performed at 90 Hz vibration to each index, middle, ring, and little finger. Two thigh MRE scans were performed at 40 Hz with knees flexed and extended. The normalized octahedral shear strain (NOSS) maps were calculated to visualize myofascial slip interfaces. The entropy of the probability distribution of the gradient NOSS was computed for the two knee positions at the intermuscular interface between vastus lateralis and vastus intermedius, around rectus femoris, and between vastus intermedius and vastus medialis.

RESULTS

NOSS map depicted distinct functional slip interfaces in the FDP for each finger. Compared to knee flexion, clearer slip interfaces and larger gradient NOSS entropy at the vastus lateralis-vastus intermedius interface were observed during knee extension, where the quadriceps are not passively stretched. This suggests the optimal position for using SII to visualize myofascial slip interface in skeletal muscles is when muscles are not subjected to any additional force.

CONCLUSION

The study demonstrated that MRE-based SII can visualize and assess myofascial interface mobility in extremities. The results provide a foundation for investigating the hypothesis that myofascial pain syndrome is characterized by changes in the mobility of myofascial interfaces.

Standardised 25-Step Traditional Thai Massage (TTM) Protocol for Treating Office Syndrome (OS)

Traditional Thai massage (TTM) is a unique form of whole body massage practiced to promote health and well-being in Thailand since ancient times. The goal of the present study was to create a standardised TTM protocol to treat office syndrome (OS) diagnosed based on the identification of the palpation of at least one so-called myofascial trigger point (MTrP) in the upper trapezius muscle. The new 90 min TTM protocol, which was developed following appropriate review of the literature and in consultation with relevant experts, has 25 distinct steps (20 pressing steps, 2 artery occlusion steps, and 3 stretching steps). Eleven TTM therapists treated three patients each using the new 90 min TTM protocol. All of the therapists reported scores greater than 80% in respect to their satisfaction and confidence to deliver the protocol, and all of the patients gave the treatment a satisfaction score of greater than 80%. The treatment produced a significant reduction in pain intensity measured on a Visual Analogue Scale (VAS), with minimum and maximum values of 0 and 10 cm, of 2.33 cm (95% CI (1.76, 2.89 cm), p < 0.001) and significant increase in pain pressure threshold (PPT) of 0.37 kg/cm² (95% CI (0.10, 0.64 kg/cm²), p < 0.05). The protocol was revised based on the feedback and the results obtained, and the new standardised TTM protocol will be applied in a randomised control trial (RCT) to compare the efficacy of TTM and conventional physical therapy (PT) for treating OS.

Effectiveness of Dry Needling of Myofascial Trigger Points in the Triceps Surae Muscles: Systematic Review

This study aims to analyze the effects of Dry Needling (DN) for the release of myofascial trigger points (MTrPs) in the triceps surae muscles (TSM). A systematic review was performed up to February 2022 in PubMed, PEDro, Scopus, CENTRAL, and Web of Science. Selection criteria were studies involving subjects older than 18 years presenting MTrPs in the TSM, without any concomitant acute or chronic musculoskeletal conditions; DN interventions applied to the MTrPs of the TSM; and results on pain, range of motion (ROM), muscle strength, muscle stiffness, and functional outcomes. The PEDro scale was used to assess the methodological quality of the studies, and the Risk of Bias Tool 2.0 to assess risk of bias. A total of 12 studies were included in the systematic review, involving 426 participants. These results suggest that DN of MTrPs in TSM could have a positive impact on muscle stiffness and functional outcomes. There are inconclusive findings on musculoskeletal pain, ROM, and muscle strength. Significant results were obtained in favor of the control groups on pressure pain thresholds. Despite the benefits obtained on muscle stiffness and functional performance, the evidence for the use of DN of MTrPs in the TSM remains inconclusive.

Immediate Effect of Dry Needling on the Viscoelastic Properties of a Trigger Point on the Infraspinatus Muscle Measured with MyotonPRO

Purpose: This article investigates the immediate effects of a dry needling (DN) puncture on the viscoelastic properties (tone, stiffness, elasticity) of a trigger point (TP) in the infraspinatus muscle in non-traumatic chronic shoulder pain. Method: Forty-eight individuals with non-traumatic chronic shoulder pain were recruited. The presence of a TP in the infraspinatus muscle was confirmed by a standardized palpatory exam. The viscoelastic properties were measured with a MyotonPRO device at baseline (T1), immediately after DN (T2), and 30 minutes later (T3). A DN puncture was applied to the TP to obtain a local twitch response while performing the technique. Results: Analyses of variance showed significant decreases in tone ( p < 0.001) and stiffness ( p = 0.003) across time after the DN technique. Post hoc tests revealed a significant reduction in tone and stiffness from T1 to T2 ( p ≤ 0.004) and no significant changes from T2 to T3 ( p ≥ 0.10). At T3, only stiffness remained significantly lower compared to T1 ( p = 0.013). Conclusions: This study brings new insights on the immediate mechanical effect of DN on tone and stiffness of TPs. Whether these effects are associated with symptom improvement and long-term effects still needs to be verified.

Reliability of shear wave elastography for the assessment of gastrocnemius fascia elasticity in healthy individual

The mechanical properties of the deep fascia, particularly their stiffness, strongly affect the development of muscle pathologies (such as compartment syndrome) and the action of the muscles. However, the mechanical characteristics of the deep muscular fascia are still not clearly understood. The present study focuses on examining the reliability of ultrasonic shear wave elastography (USWE) devices in quantifying the shear modulus of the gastrocnemius fascia in healthy individuals, particularly their ability to measure the shear modulus of the deep fascia of the gastrocnemius during ankle dorsiflexion. Twenty-one healthy males (age: 21.48 ± 1.17 years) participated in the study. Using USWE, the shear moduli of the medial gastrocnemius fascia (MGF) and lateral gastrocnemius fascia (LGF) were quantified at different angles during passive lengthening. The two operators took turns measuring each subject's MGF and LGF over a 1-h period, and operator B took an additional measurement 2 h later. For the intra-operator test, the same subjects were measured again at the same time of day 5 days later. Both the intrarater [intraclass correlation coefficient (ICC) = 0.846-0.965)] and interrater (ICC = 0.877-0.961) reliability values for measuring the shear moduli of the MGF and LGF were rated as excellent; the standard error of the mean (SEM) was 3.49 kPa, and the minimal detectable change (MDC) was 9.68 kPa. Regardless of the ankle angle, the shear moduli of the LGF were significantly greater than that of the MGF (p < 0.001). Significant increases in the shear moduli of both the MGF and the LGF were observed in the neutral position compared to the relaxed position. These results indicate that USWE is a reliable technique to assess the shear modulus of the gastrocnemius fascia and detect its dynamic changes during ankle dorsiflexion. USWE can be used for biomechanical studies and intervention experiments concerning the deep fascia.

Trigger Point Injections

Myofascial pain and myofascial pain syndromes are among some of the most common acute and chronic pain conditions. Many interventional procedures can be performed in both an acute and chronic pain setting to address myofascial pain syndromes. Trigger point injections can be performed with or without imaging guidance such as fluoroscopy and ultrasound; however, the use of imaging in years past has been recommended to improve patient outcome and safety. Injections can be performed using no injectate (dry needling), or can involve the administration of local anesthetics, botulinum toxin, or corticosteroids.

Assessment of Myofascial Trigger Points via Imaging: A Systematic Review

ABSTRACT

This study systematically reviewed the published literature on the objective characterization of myofascial pain syndrome and myofascial trigger points using imaging methods. PubMed, Embase, Ovid, and the Cochrane Library databases were used, whereas citation searching was conducted in Scopus. Citations were restricted to those published in English and in peer-reviewed journals between 2000 and 2021. Of 1762 abstracts screened, 69 articles underwent full-text review, and 33 were included. Imaging data assessing myofascial trigger points or myofascial pain syndrome were extracted, and important qualitative and quantitative information on general study methodologies, study populations, sample sizes, and myofascial trigger point/myofascial pain syndrome evaluation were tabulated. Methodological quality of eligible studies was assessed based on the Quality Assessment of Diagnostic Accuracy Studies criteria. Biomechanical properties and blood flow of active and latent myofascial trigger points assessed via imaging were found to be quantifiably distinct from those of healthy tissue. Although these studies show promise, more studies are needed. Future studies should focus on assessing diagnostic test accuracy and testing the reproducibility of results to establish the best performing methods. Increasing methodological consistency would further motivate implementing imaging methods in larger clinical studies. Considering the evidence on efficacy, cost, ease of use and time constraints, ultrasound-based methods are currently the imaging modalities of choice for myofascial pain syndrome/myofascial trigger point assessment.

Liver stiffness measured by magnetic resonance elastography in early recurrence of hepatocellular carcinoma after treatment: A protocol for systematic review and meta analysis

BACKGROUND

With high diagnostic accuracy, magnetic resonance elastography (MRE) is a noninvasive tool and can be adopted to measure liver stiffness (LS). In this study, meta-analysis was carried out to further evaluate whether LS measured by MRE can predict early recurrence in patients with hepatocellular carcinoma (HCC).

METHODS

PUBMED, EMBASE, Web of Science, China National Knowledge Infrastructure, and Cochrane Library database were searched for studies related to LS measured by MRE in the prediction of recurrence in patients with HCC. Survival outcome was estimated by hazard ratios and 95% confidence intervals. Meta-analysis was conducted with the Stata 16.0.

RESULTS

The results of this meta-analysis will be submitted to a peer-reviewed journal for publication.

CONCLUSION

This study will provide evidence support for LS measured by MRE in predicting the recurrence of HCC.

ETHICS AND DISSEMINATION

The private information from individuals will not be published. This systematic review also should not damage participants' rights. Ethical approval is not available. The results may be published in a peer-reviewed journal or disseminated in relevant conferences.

OSF REGISTRATION NUMBER

DOI 10.17605/ OSF.IO / SURH3.

Quantitative Shear Wave Speed Assessment for Muscles with the Diagnosis of Taut Bands and/or Myofascial Trigger Points Using Probe Oscillation Shear Wave Elastography: A Pilot Study

OBJECTIVE

To use probe oscillation shear wave elastography (PROSE) with two vibration sources to generate two shear waves in the imaging plane to quantitatively assess the shear wave speeds (SWSs) of muscles with and without the diagnosis of taut bands (TB) and/or myofascial trigger points (MTrPs).

METHODS

Thirty-three patients were scanned with the PROSE technique. Shear waves were generated through continuous vibration of the ultrasound probe, while the shear wave motions were detected using the same probe. SWSs for the sides with and without TBs and/or MTrPs were computed and compared. The pressure pain thresholds (PPTs) were measured as an indicator of maximum pain tolerance of patients. The statistical differences between the SWSs with and without TBs and/or MTrPs with different PPT values were analyzed using the nonparametric Wilcoxon rank-sum test.

RESULTS

The mean SWSs for the sides with TBs and/or MTrPs are faster than that of the contralateral side without TBs and/or MTrPs. A significant difference was observed between mean SWSs with and without TBs and/or MTrPs without any information of PPT, with rank-sum test P <  .005. Additionally, with the information of PPT, a significant difference was observed between mean SWSs for the sides with and without TBs and/or MTrPs, for PPT values between 0 and 50 N/cm² (P <  .005), but for PPT values between 50 and 90 N/cm² , it was difficult to differentiate mean SWSs with and without TBs and/or MTrPs.

CONCLUSION

Our preliminary results show that SWSs measured from patients had a significant difference between the mean SWSs with and without TBs and/or MTrPs.

Properties of muscle nodules recognized by manual physical therapy practitioners

[Purpose] The purpose of this study was to describe the properties of muscle nodules (kinkoketsu) recognized by manual physical therapy practitioners. [Participants and Methods] A total of one hundred and thirty-three physical therapists, occupational therapists, judo therapists, and acupuncturists participated in this study. The shape, size, direction, depth, and hardness of muscle nodules, often treated in the buttocks, were investigated through the completion of a questionnaire. [Results] A total of 124 answer sheets were completed; 112 of these described the shape of muscle nodules as ellipsoidal. Of these 112 sheets, 97 effective sheets were analyzed. The results showed that the mean long axis length, short axis length, and thickness of the muscle nodules were 30.9 mm, 16.2 mm, and 9.3 mm, respectively. The most common responses on the long axis direction, depth, and hardness of the muscle nodules were the craniocaudal orientation, the second shallowest layer of 5 divisions, and the eraser level, respectively. [Conclusion] The typical muscle nodule found in the buttocks by manual physical therapy practitioners is roughly the shape of a large almond.

A Comprehensive Review of the Treatment and Management of Myofascial Pain Syndrome

PURPOSE OF REVIEW

Myofascial pain syndrome (MPS) is a musculoskeletal pain condition that stems from localized, taut regions of skeletal muscle and fascia, termed trigger points. The purpose of this comprehensive review is to provide updated information on prevalence, pathophysiology, and treatment modalities with a focus on interventional modalities in managing MPS.

RECENT FINDINGS

Though MPS can present acutely, it frequently presents as a chronic condition, affecting up to 85% of adults during their lifetime. MPS is an often-overlooked component of pain with overarching effects on society, including patient quality of life, physical and social functioning, emotional well-being, energy, and costs on health care. The prevalence of MPS is generally increased among patients with other chronic pain disorders and has been associated with various other conditions such as bladder pain syndrome, endometriosis, and anxiety. MPS is poorly understood and remains a challenging condition to treat. Non-pharmacologic treatment modalities such as acupuncture, massage, transcutaneous electrical stimulation, and interferential current therapy may offer relief to some patients with MPS. Additional studies are warranted to get a better understanding of managing myofascial pain.

Magnetic resonance elastography of the supraspinatus muscle: A preliminary study on test-retest repeatability and wave quality with different frequencies and image filtering

The purpose of this study was to determine an optimal condition (vibration frequency and image filtering) for stiffness estimation with high accuracy and stiffness measurement with high repeatability in magnetic resonance elastography (MRE) of the supraspinatus muscle. Nine healthy volunteers underwent two MRE exams separated by at least a 30 min break, on the same day. MRE acquisitions were performed with a gradient-echo type multi-echo MR sequence at 75, 100, and 125 Hz pneumatic vibration. Wave images were processed by a bandpass filter or filter combining bandpass and directional filters (bandpass-directional filter). An observer specified the region of interest (ROI) on clear wave propagation in the supraspinatus muscle, within which the observer measured the stiffness. This study assessed wave image quality according to two indices, as a substitute for the assessment of the accuracy of the stiffness estimation. One is the size of the clear wave propagation area (ROI size used to measure the stiffness) and the other is the qualitative stiffness resolution score in that area. These measurements made by the observer were repeated twice at least one month apart after each MRE exam. This study assessed the intra-examiner and observer repeatability of the stiffness value, ROI size and resolution score in each combination of vibration frequency and image filter. Repeatability of the data was analyzed using the intraclass correlation coefficient (ICC) and 95% limits-of-agreement (LOA) in Bland-Altman analysis. The analyses on intra-examiner and observer repeatability of stiffness indicated that the ICC and 95% LOA were not varied greatly depending on vibration frequency and image filter (intra-examiner repeatability, ICC range, 0.79 to 0.88; 95% LOA range, ±23.95 to ±32.42%, intra-observer repeatability, ICC range, 0.98 to 1.00; 95% LOA range, ±5.10 to ±10.99%). In the analyses on intra-examiner repeatability of ROI size, ICCs were rather low (ranging from: 0.03 to 0.69) while 95% LOA was large in all the combinations of vibration frequency and image filter (ranging from: ±62.66 to ±83.33%). In the analyses on intra-observer repeatability of ROI size, ICCs were sufficiently high in the total combination of vibration frequency and image filter (ranging from 0.80 to 0.87) while the 95% LOAs were better (lower) in the bandpass-directional filter than the bandpass filter (bandpass directional filter vs. bandpass filter, ±28.81 vs. ±54.83% at 75 Hz; ±25.63 vs. ±37.83% at 100 Hz; ±34.51 vs. ±43.36% at 125 Hz). In the analyses on intra-examiner and observer repeatability of resolution score, the mean difference (bias) between the two exams (or observations) was significantly low and there was almost no difference across all the combinations of vibration frequency and image filter (range of bias: -0.11-0.11 and -0.17-0.00, respectively). Additionally, effects of vibration frequency and image filter on wave image quality (ROI size and resolution score) were assessed separately in each exam. Both mean ROI size and resolution score in the bandpass-directional filter were larger than those in the bandpass filter. Among the data in the bandpass-directional filter, mean ROI size was larger at 75 and 100 Hz, and mean resolution score was larger at 100 and 125 Hz. Taking into consideration with the results of repeatability and wave image quality, the present results suggest that optimal vibration frequency and image filter for MRE of the supraspinatus muscles is 100 Hz and bandpass-directional filter, respectively.

Change in muscle hardness after trigger point injection and physiotherapy for myofascial pain syndrome

Assessment and treatment of masticatory myofascial pain syndrome (MPS) are not standardized and remain controversial. We examined whether muscle hardness was useful for evaluating masticatory MPS and analyzed the effectiveness of treatments such as stretching and massage (SM) and trigger point injection (TPI). Twenty healthy volunteers and 20 MPS patients were enrolled. MPS patients were divided into TPI and SM treatment groups. Hardness of masticatory muscle with a taut band (TB) and change in hardness were evaluated after SM and TPI treatments. Hardness values were significantly higher in muscle including a TB (TB point) than in the muscle of healthy controls. Visual analogue scale scores were significantly lower after SM and TPI treatments, and hardness of the TB point was significantly lower after SM but not after TPI. These results suggest that measurement of muscle hardness, including the TB, is useful for evaluating masticatory MPS. However, TPI analgesia might not be caused by change in muscle hardness. The mechanisms underlying the effects of SM and TPI on reducing pain in MPS may differ and thus warrant further research.

Simultaneous acquisition of magnetic resonance elastography of the supraspinatus and the trapezius muscles

We developed a Magnetic Resonance elastography (MRE) technique using a conventional magnetic resonance imaging (MRI), which allows a simultaneous elastography of the supraspinatus and trapezius muscles, by designing a new wave transducer (vibration pad) and optimizing the mechanical vibration frequency. Five healthy volunteers underwent an MRE. In order to transmit the mechanical vibration (pneumatic vibration) to the supraspinatus and trapezius muscles, a new vibration pad was designed using a three-dimensional (3D) printer. The vibration pad was placed on the skin 2 cm medial and 2 cm cephalad the deltoid tubercle. MRE acquisition was performed with a multi-slice gradient-echo type multi-echo MR sequence, which allows MREs even in a conventional MRI; two oblique axial images of the supraspinatus and trapezius muscles were obtained simultaneously. Vibration frequencies were set at 50-150 Hz, with a 25 Hz step. Wave image quality in each frequency was analyzed using a phase-to-noise ratio (PNR) and clarity of propagating wave that was assessed by two readers qualitatively. In the supraspinatus muscle, the wave images were of good quality especially at frequencies >75 Hz. In the trapezius muscle, the wave images were of better quality at low frequencies (50 and 75 Hz) compared with high frequencies (100-150 Hz). The PNR of both muscles were higher at low frequencies. The mean stiffness in the trapezius muscle (7.26 ± 2.13 kPa at 75 Hz) was larger than those in the supraspinatus muscle (4.16 ± 0.50 kPa at 75 Hz). The results demonstrated that our MRE technique allows simultaneous assessment of the stiffness in the supraspinatus and trapezius muscles using a conventional MRI, and that optimal vibration frequency for simultaneous MRE of these muscles is 75 Hz. This technique provides a new means for early detection of abnormality in the shoulder.

Development of a robust diffusion-MR elastography (dMRE) technique to mitigate intravoxel phase dispersion

Diffusion-magnetic resonance elastography (dMRE) is an emerging practical technique that can acquire diffusion magnetic resonance imaging and MRE simultaneously. However, a signal loss attributable to intravoxel phase dispersion (IVPD) interferes with the calculation of the apparent diffusion coefficient (ADC). This study presents an approach to dMRE that reduces the influence of IVPD by introducing a new pulse sequence. The existing and proposed techniques were performed using a phantom comprising five rods with different elasticities at 60 Hz vibration to investigate the accuracy of previous and proposed dMRE techniques. The measures of ADC and stiffness, obtained by using both dMRE techniques, were compared with conventional spin-echo (SE) diffusion and SE-MRE. Then, we evaluated those differences by using the mean of absolute differences (MAD) in each rod within the phantom. The results of the MAD of the stiffness from both dMRE techniques showed almost no difference. In contrast, the value of the ADC MAD (MAD ≒ 0.16 × 10^-3 mm²/s), obtained in the soft region within the phantom with the previous dMRE technique, was large. This value was about 2.7 times that of the value produced by the proposed dMRE technique. This difference must reflect the degree of influence of IVPD in both techniques. These results demonstrate that our dMRE technique is a robust method for addressing the signal loss attributable to IVPD.

Myofascial Pelvic Pain and Related Disorders

Myofascial pelvic pain refers to pain in the pelvic floor muscles, the pelvic floor connective tissue, and the surrounding fascia. The cause is often multifactorial and requires treatment that encompasses multiple modalities. This type of pain is often associated with other abdominopelvic disorders, so providers in these specialties need to be aware of these connections. A comprehensive musculoskeletal examination, including evaluation of the pelvic floor muscles, and history are key to diagnosing myofascial pelvic pain. Treatments include physical therapy, muscle relaxers, oral neuromodulators, cognitive-behavioral therapy, and pelvic floor muscle injections.

Posterior Shoulder Tightness: To Treat or Not to Treat?

Shoulder pain is a common musculoskeletal complaint that is difficult to treat because of the biomechanical complexity of the shoulder region, the interplay between mobility and stability, and the vital role played by the shoulder in moving, positioning, and providing stability for hand function. Despite advances in biomechanics and pain science, there is still much to learn about how impairments influence shoulder function and health. One impairment, posterior shoulder tightness (PST), is often noted in individuals with shoulder pain and consequently has generated much discussion and debate in recent years. Range-of-motion shifts and deficits are the clinical indicators of PST, with 3 tissue alterations potentially contributing to these modifications: (1) increased humeral retrotorsion (retroversion), (2) reduced posterior glenohumeral joint capsule extensibility, and (3) reduced posterior shoulder muscle/tendon extensibility. The significance of each alteration for shoulder function and the interaction among them remain unclear. It is also unknown if, or to what extent, these impairments can be resolved through interventions. This raises a clinically relevant and straightforward question: when PST is present, should we treat or not treat? In this Viewpoint, we will debate this question and propose that physical therapy interventions have the potential to improve only 1 of the 3 tissue alterations contributing to PST. J Orthop Sports Phys Ther 2018;48(3):133-136. doi:10.2519/jospt.2018.0605.

Numerical simulations of magnetic resonance elastography using finite element analysis with a linear heterogeneous viscoelastic model

Abstract

Magnetic resonance elastography (MRE) is a technique to identify the viscoelastic moduli of biological tissues by solving the inverse problem from the displacement field of viscoelastic wave propagation in a tissue measured by MRI. Because finite element analysis (FEA) of MRE evaluates not only the viscoelastic model for a tissue but also the efficiency of the inversion algorithm, we developed FEA for MRE using commercial software called ANSYS, the Zener model for displacement field of a wave inside tissue, and an inversion algorithm called the modified integral method. The profile of the simulated displacement field by FEA agrees well with the experimental data measured by MRE for gel phantoms. Similarly, the value of storage modulus (i.e., stiffness) recovered using the modified integral method with the simulation data is consistent with the value given in FEA. Furthermore, applying the suggested FEA to a human liver demonstrates the effectiveness of the present simulation scheme.

Graphical abstract

Reliability of the Upper Trapezius Muscle and Fascia Thickness and Strain Ratio Measures by Ultrasonography and Sonoelastography in Participants With Myofascial Pain Syndrome

Objective

The purpose of this study was to assess the intra- and interexaminer reliability of the upper trapezius muscle and fascia thickness measured by ultrasonography imaging and strain ratio by sonoelastography in participants with myofascial pain syndrome.

Methods

Thirty-two upper trapezius muscles were assessed. Two examiners measured the upper trapezius thickness and strain ratio 3 times by ultrasonography and sonoelastography independently in the test session. The retest session was completed 6 to 8 days later.

Results

A total of 87.5% of participants had trigger points on the right side, and 22.5% had trigger points on the left side. For the test session, the average upper trapezius thickness, fascia thickness, and strain ratio measured by first and second examiners were 11.86 mm and 11.56 mm, 1.23 mm and 1.25 mm, and 0.94 and 0.99, respectively. For the retest session, the previously mentioned parameters obtained by first and second examiners were 11.76 mm and 11.39 mm, 1.27 mm and 1.29 mm, and 0.96 and 0.99, respectively. The intraclass correlation coefficients indicated good to excellent reliability for both within-intraexaminer (0.78-0.96) and between-intraexaminer (0.75-0.98) measurements. Also, the intraclass correlation coefficients and standard errors of measurement of interexaminer reliability ranged between 0.88 to 0.93 and 0.05 to 0.44 for both muscle and fascia thickness and 0.70 to 0.75 and 0.04 to 0.20 for strain ratio of upper trapezius, respectively.

Conclusion

Upper trapezius thickness measurements by ultrasonography and strain ratio by sonoelastography are reliable methods in participants with myofascial pain syndrome.

A MRI-Compatible Combined Mechanical Loading and MR Elastography Setup to Study Deformation-Induced Skeletal Muscle Damage in Rats

Deformation of skeletal muscle in the proximity of bony structures may lead to deep tissue injury category of pressure ulcers. Changes in mechanical properties have been proposed as a risk factor in the development of deep tissue injury and may be useful as a diagnostic tool for early detection. MRE allows for the estimation of mechanical properties of soft tissue through analysis of shear wave data. The shear waves originate from vibrations induced by an external actuator placed on the tissue surface. In this study a combined Magnetic Resonance (MR) compatible indentation and MR Elastography (MRE) setup is presented to study mechanical properties associated with deep tissue injury in rats. The proposed setup allows for MRE investigations combined with damage-inducing large strain indentation of the Tibialis Anterior muscle in the rat hind leg inside a small animal MR scanner. An alginate cast allowed proper fixation of the animal leg with anatomical perfect fit, provided boundary condition information for FEA and provided good susceptibility matching. MR Elastography data could be recorded for the Tibialis Anterior muscle prior to, during, and after indentation. A decaying shear wave with an average amplitude of approximately 2 μm propagated in the whole muscle. MRE elastograms representing local tissue shear storage modulus G_d showed significant increased mean values due to damage-inducing indentation (from 4.2 ± 0.1 kPa before to 5.1 ± 0.6 kPa after, p<0.05). The proposed setup enables controlled deformation under MRI-guidance, monitoring of the wound development by MRI, and quantification of tissue mechanical properties by MRE. We expect that improved knowledge of changes in soft tissue mechanical properties due to deep tissue injury, will provide new insights in the etiology of deep tissue injuries, skeletal muscle damage and other related muscle pathologies.

Posterior, Lateral, and Anterior Hip Pain Due to Musculoskeletal Origin: A Narrative Literature Review of History, Physical Examination, and Diagnostic Imaging

OBJECTIVE

The purpose of this study was to present a narrative review of the literature of musculoskeletal causes of adult hip pain, with special attention to history, physical examination, and diagnostic imaging.

METHODS

A narrative review of the English medical literature was performed by using the search terms "hip pain" AND "anterior," "lateral," and "posterior." Additionally, specific entities of hip pain or pain referral sources to the hip were searched for. We used the PubMed search engine through January 15, 2016.

RESULTS

Musculoskeletal sources of adult hip pain can be divided into posterior, lateral, and anterior categories. For posterior hip pain, select considerations include lumbar spine and femoroacetabular joint referral, sacroiliac joint pathology, piriformis syndrome, and proximal hamstring tendinopathy. Gluteal tendinopathy and iliotibial band thickening are the most common causes of lateral hip pain. Anterior hip pain is further divided into causes that are intra-articular (ie, labral tear, osteoarthritis, osteonecrosis) and extra-articular (ie, snapping hip and inguinal disruption [athletic pubalgia]). Entrapment neuropathies and myofascial pain should also be considered in each compartment. A limited number of historical features and physical examination tests for evaluation of adult hip pain are supported by the literature and are discussed in this article. Depending on the clinical differential, the gamut of diagnostic imaging modalities recommended for accurate diagnosis include plain film radiography, computed tomography, magnetic resonance imaging, skeletal scintigraphy, and ultrasonography.

CONCLUSIONS

The evaluation of adult hip pain is challenging. Clinicians should consider posterior, lateral, and anterior sources of pain while keeping in mind that these may overlap.

Quantification of dry needling on myofascial trigger points using a novel ultrasound method: A study protocol

INTRODUCTION

Myofascial pain syndrome (MPS) is a neuromuscular dysfunction consisting of both motor and sensory abnormalities. Considering the high prevalence of MPS and its related disabilities and costs, this study was designed to determine the reliability of new ultrasonographic indexes of the upper trapezius muscle as well as the sensitivity and specificity of 2D ultrasound imaging for diagnostic purposes. Furthermore, we sought to evaluate the effectiveness of dry needling (DN) on studied ultrasonographic indexes.

MATERIALS AND METHODS

This study will be performed in two steps with two different designs. The first is a pilot study and was designed as a semi-experimental study to determine the sensitivity and specificity of ultrasonography for the diagnosis of MPS and the reliability of ultrasonographic measurements like muscle thickness, area of myofascial trigger points (MTrPs) in longitudinal view, echogenicity of MTrPs in longitudinal view, echogenicity of muscle with MTrPs in longitudinal and transverse views, and pennation angle of upper trapezius muscle. The second study is an interventional study which was designed to investigate the effectiveness of DN on ultrasonographic measurements, for which the reliability was determined in the first study.

CONCLUSION

we will quantify the effectiveness of DN on MTrPs and muscle tissue by using novel ultrasonographic indexes. The results of the current study will provide baseline information to design more interventional studies to improve the evaluation of other treatments of MPS.

Magnetic resonance elastography (MRE) for measurement of muscle stiffness of the shoulder: feasibility with a 3 T MRI system

BACKGROUND

Magnetic resonance elastography (MRE) at 3 T MR has the potential to improve the objective detection of skeletal muscle stiffness.

PURPOSE

To determine the feasibility of MRE using 3 T MR for measurement of the stiffness of shoulder muscles in subjects.

MATERIAL AND METHODS

This study prospectively evaluated 16 healthy subjects (mean age, 29.8 years; range, 25-51 years). MRE was acquired with 3 T MR through the use of a 2D-gradient-echo-based MRE sequence at two different excitation frequencies (90 and 120 Hz). The mean stiffness values (MSV) of the trapezius and infraspinatus muscles were measured by two radiologists. Differences between the MSV in the x, y, and z motion-sensitization directions were assessed. Inter-observer agreement was also measured.

RESULTS

The MSV of the trapezius muscle were 2.72 kPa ± 0.6 (SD) at 90 Hz and 4.66 kPa ± 1.2 at 120 Hz, while the MSV for the infraspinatus muscle were 3.2 kPa ± 0.52 at 90 Hz and 4.38 kPa ± 0.92 at 120 Hz. The MSV for both muscles were significantly higher at 120 Hz than at 90 Hz (P < 0.05). The MSV in the three different directions were significantly different from each other in the infraspinatus muscle (P < 0.05). Levels of inter-observer agreement regarding MSV were good to excellent for both the trapezius (intraclass correlation coefficient [ICC] = 0.979-0.996) and infraspinatus muscles (ICC = 0.614-0.943).

CONCLUSION

MRE at 3 T is a feasible technique for the evaluation of shoulder muscle stiffness. Extended application of skeletal muscle MRE at 3 T will contribute to the evaluation and treatment of skeletal muscle disorders.

The immediate effect of multiple mechanical impulses on electromyography and pressure pain threshold of lumbar latent trigger points: an experimental study

BACKGROUND

Myofascial pain is a common syndrome, which has not been studied extensively in the low back. Despite a variety of manual and instrument assisted interventions available, little work has targeted the possible effects of fast mechanical impulses on myofascial trigger points (MTrPs) on its sensitivity and electrical activity. The purpose of this experimental study was to quantify the immediate effect of one session of mechanical impulses to lumbar latent MTrPs and to normal muscle tissue with pressure pain threshold (PPT) and surface electromyography (sEMG) as outcome measures.

METHODS

During the autumn of 2009, in 41 asymptomatic subjects between 17-40 years of age the lumbar musculature was searched for a latent MTrP by a trained clinician. Using 3 disposable pre-gelled electrodes bilaterally, sEMG was recorded continuously from muscle containing either latent or no MTrP. Both the trigger point group and control group received the intervention and were blinded to group allocation. The immediate effects of mechanical impulses were assessed by sEMG and PPT before and after intervention using Wilcoxon matched-pairs signed-ranks test, Mann-Whitney U test and paired t-tests.

RESULTS

The PPT increased significantly across both groups (p < 0.01) after intervention. The proportionate increase (14.6 %) was comparable in both MTrP and control groups. The electrical activity on the MTrP side was not significantly higher in the MTrP group compared to the contralateral side. The decrease of resting electrical activity after intervention was significant in the MTrP group on the side of the latent MTrP (P = 0.001) as well as the contralateral side (p=0.022), and not significant in the control group on either side (p=0.33 and p=0.93).

CONCLUSION

In this study, the immediate effect of one session of mechanical impulses was associated with a significant increase in PPT for both groups and a significant decrease in the resting electrical activity of the lumbar muscles only in the MTrP group. It is unknown if these effects have clinical significance.

A critical overview of the current myofascial pain literature - March 2016

The worldwide interest in myofascial pain syndrome (MPS) and trigger points (TrPs) is reflected in the increasing number of publications. In this overview of the literature, we included 26 studies, case reports and review articles by authors from 18 different countries. Several research groups are exploring the characteristic of TrPs such as Chen and colleagues, who continued their work on the quantification of the taut bands. Meng and colleagues studied the relationships between TrPs and central sensitization, while Yu and colleagues examined the electrophysiological characteristics that occur as a result of active TrPs. Several researchers used objective measurements to determine clinical outcomes, such as Koppenhaver and colleagues who measured objective changes in the function and nociceptive sensitivity of lumbar multifidus muscle subjects with low back pain. Turo and colleagues quantified muscle tissue changes after dry needling in chronic myofascial pain using elastography. Multiple studies explored various treatment options for TrPs, such as dry needling, injections with lidocaine or granisetron, traditional Thai massage, self-myofascial release, kinesiotaping, and monochromatic infrared photo energy, among others.

A comparison between different modes of real-time sonoelastography in visualizing myofascial trigger points in low back muscles

OBJECTIVE

Currently, there is a lack of objective means to quantify myofascial trigger points (MTrPs) and their core features. Our research compares (1) MTrPs and surrounding myofascial tissue using two-dimensional grayscale ultrasound (2DGSUS) and vibration sonoelastography (VSE); (2) the accuracy of both modes in visualizing MTrPs; (3) 'active' and 'latent' MTrPs, using VSE; and (4) the accuracy of both modes in visualizing deep and superficially located MTrPs.

METHODS

Fifty participants with more than two MTrPs in their quadratus lumborum, longissimus thoracis, piriformis, and gluteus medius muscles were assigned to an active MTrP (low back pain) group or a latent (currently pain free) MTrP group. MTrP identification was based on their essential criteria. An electronic algometer measured repeatedly the tenderness of MTrPs with reference to pressure pain threshold values. A handheld vibrator was applied over MTrPs, while VSE and 2DGSUS readings were taken using an EUB-7500 ultrasound scanner.

RESULTS

There was a significant difference between MTrP strain and that of the immediately surrounding myofascial tissue, as measured using VSE (P = 0·001). VSE visualized all superficial and deep MTrPs with an accuracy of 100% (for both groups); the blinded results obtained using 2DGSUS achieved 33% and 35% accuracy, respectively. There was no significant difference found between the tissue strain ratios of active and latent MTrPs (P = 0·929).

DISCUSSION

Sonoelastography can visualize superficial and deep MTrPs, and differentiate them from surrounding myofascial structure through tissue stiffness and echogenicity. VSE was more accurate than 2DGSUS in visualizing and imaging MTrPs.

Quantification of Myofascial Taut Bands

OBJECTIVE

To assess the correlation of clinician-identified myofascial taut bands with their presence and characteristics on magnetic resonance elastography (MRE) imaging.

DESIGN

Cross-sectional study.

SETTING

A magnetic resonance imaging (MRI) research laboratory.

PARTICIPANTS

A convenience sample of adults (N=65; 45 women, 20 men) identified by skilled musculoskeletal physicians as having upper trapezius myofascial pain-associated taut bands.

INTERVENTIONS

Subjects had their taut bands outlined and were positioned within a 1.5T MRI machine. Shear waves were induced with a pneumatic transducer located over the belly of the involved muscle. Wave propagation was visualized with MRE images across a vibration cycle. Imaging data were assessed independently by 2 skilled MRE interpreters.

MAIN OUTCOME MEASURES

The primary outcome measure was the determination of the intra- and interrater reliabilities of MRE taut band identification and their correlation with clinician identification of band presence. Secondary outcomes consisted of the elucidation of the physical characteristics of taut bands and their surrounding muscle tissue.

RESULTS

MRE intra- and interrater reliability was excellent, with kappa coefficients and 95% confidence intervals (CIs) of .86 (.68-1.00) and .93 (.79-1.00), respectively. Stiffness in MRE-identified taut bands was elevated at a mean ± SD of 11.5±2.4 kPa and fell to 5.8±0.9 kPa in surrounding muscle tissue (P<.001); muscular tone in trapezius muscles without a taut band was relatively uniform at 6.6±2.1 kPa. Agreement between the physicians and the MRE raters, however, was relatively poor (63.1%; 95% CI, 50.2%-74.7%).

CONCLUSIONS

Our findings suggest that while clinicians may overestimate, and current MRE techniques may underestimate, the presence of taut bands, these bands do exist, can be assessed quantitatively, and do represent localized areas of increased muscle stiffness.

Skin Resistivity Value of Upper Trapezius Latent Trigger Points

Introduction. The skin resistivity (SkR) measurement is commonly recommended for acupoints measurement, but for trigger points (TrPs) only one study is available. The purpose of the study was to evaluate SkR for latent TrPs compared to non-TrPs and the surrounding tissue. Material and Methods. Forty-two healthy volunteers with unilateral latent upper trapezius TrPs (12 men, 30 women) aged 21–23 (mean age: 22.1 ± 0.6 y) participated in the study. Keithley electrometer 610B was used for measuring SkR (Ag/AgCl self-adhesive, disposable ground electrode: 30 mm diameter). SkR was measured for latent TrPs and compared to opposite non-TrPs sites and the surrounding tissue. Results. The SkR decrease of TrPs-positive sites as compared to TrPs-negative sites and the surrounding tissue was confirmed. However, no statistically significant difference in the SkR value occurred when all data were analyzed. The same was confirmed after gender division and for TrPs-positive subjects examined for referred pain and twitch response presence. Conclusion. SkR reactive changes at latent TrPs are possible but the results were not consistent with the previous study. Thus, caution in applying SkR to latent TrPs isolation is recommended and its clinical use should not be encouraged yet. Further studies, especially on active TrPs, are yet required.

Signs and Symptoms of Myofascial Pain: An International Survey of Pain Management Providers and Proposed Preliminary Set of Diagnostic Criteria

OBJECTIVE

Myofascial Pain Syndrome (MPS) is highly prevalent in pain medicine, yet there is no "gold standard" or set of validated diagnostic criteria for clinical or research use. A survey collected clinician perspectives on MPS to foster the development of a formal case definition for empirical validation.

DESIGN

International survey.

METHODS

Clinician members of the International Association for the Study of Pain and the American Academy of Pain Medicine received a survey of the symptoms and signs of MPS and expected response to treatment. Write-in fields were available for each category and to suggest relevant diagnostic studies.

RESULTS

Two hundred fourteen responses were received from 4,143 surveys mailed. The most essential components of MPS were tender spots that recreate symptoms when palpated. MPS was also associated with muscle stiffness, decreased range of motion of the affected joints, worsening symptoms with stress, palpable taut band or tender nodule, and referred pain with palpation of the tender spot. Diagnostic studies are reported to be useful for ruling out other pathology, but not to confirm the presence of the condition.

CONCLUSIONS

These results were used to propose a set of preliminary diagnostic criteria; expert consensus for case definition and subsequent empirical validation are required for standardization in research and clinical management of MPS.

Dry Needling Related Short-Term Vasodilation in Chronic Sciatica under Infrared Thermovision

Vasomotor responses to dry needling (DN) of trigger points (TrPs) under infrared thermovision (IRT) camera control and TrPs coexistence in chronic sciatica patients have never been studied. Materials and Methods. Fifty consecutive chronic sciatica patients were enrolled in the study. DN under IRT control was performed for all patients regardless of gluteus minimus (GM) active TrPs examination. Then, the vasomotor response and its agreement with TrPs examination were evaluated. Results. The prevalence of GM active TrPs was 32%. DN provokes intensive vasodilatation for TrPs-positive patients only, with the localization dependent on referred pain during the procedure (r = 0.896;  P = 0.000) not the daily complaint. The increase of vasodilatation was, for example, for thigh, TrPs-positive +30.29% (P < 0.05) versus TrPs-negative +4.08%. Additionally, a significant skin temperature increase was observed for TrPs-positive only, for example, thigh +1.5 ± 1.3°C (maximum) and +1.2 ± 1.0°C (average) (both P < 0.05). Conclusion. GM active TrPs prevalence among chronic sciatica patients was around one in three. Every TrPs-positive subject presented with vasodilatation under IRT in the area of DN related referred pain. Although TrPs involvement in chronic sciatica patients is possible, further studies on a bigger group of patients are still required.

A critical evaluation of Quintner et al: missing the point

The objective of this article is to critically analyze a recent publication by Quinter, Bove and Cohen, published in Rheumatology, about myofascial pain syndrome and trigger points (Quintner et al., 2014). The authors concluded that the leading trigger point hypothesis is flawed in reasoning and in science. They claimed to have refuted the trigger point hypothesis. The current paper demonstrates that the Quintner et al. paper is a biased review of the literature replete with unsupported opinions and accusations. In summary, Quintner et al. have not presented any convincing evidence to believe that the Integrated TrP Hypothesis should be laid to rest.

Dynamic ultrasound imaging applications to quantify musculoskeletal function

Advances in imaging methods have led to new capability to study muscle and tendon motion in vivo. Direct measurements of muscle and tendon kinematics using imaging may lead to improved understanding of musculoskeletal function. This review presents quantitative ultrasound methods for muscle dynamics that can be used to assess in vivo musculoskeletal function when integrated with other conventional biomechanical measurements.

A critical evaluation of the trigger point phenomenon

The theory of myofascial pain syndrome (MPS) caused by trigger points (TrPs) seeks to explain the phenomena of muscle pain and tenderness in the absence of evidence for local nociception. Although it lacks external validity, many practitioners have uncritically accepted the diagnosis of MPS and its system of treatment. Furthermore, rheumatologists have implicated TrPs in the pathogenesis of chronic widespread pain (FM syndrome). We have critically examined the evidence for the existence of myofascial TrPs as putative pathological entities and for the vicious cycles that are said to maintain them. We find that both are inventions that have no scientific basis, whether from experimental approaches that interrogate the suspect tissue or empirical approaches that assess the outcome of treatments predicated on presumed pathology. Therefore, the theory of MPS caused by TrPs has been refuted. This is not to deny the existence of the clinical phenomena themselves, for which scientifically sound and logically plausible explanations based on known neurophysiological phenomena can be advanced.

Objective measurement of tissue tension in myofascial trigger point areas before and during the administration of anesthesia with complete blocking of neuromuscular transmission

OBJECTIVES

Myofascial trigger points (MTPs) are extremely frequent in the human musculoskeletal system. Despite this, little is known about their etiology. Increased muscular tension in the trigger point area could be a major factor for the development of MTPs. To investigate the impact of muscular tension in the taut band with an MTP and thereby, the spinal excitability of associated segmental neurons, we objectively measured the tissue tension in MTPs before and during the administration of anesthesia using a transducer.

METHODS

Three target muscles (m. temporalis, upper part of m. trapezius, and m. extensor carpi radialis longus) with an MTP and 1 control muscle without an MTP were examined in 62 patients scheduled for an operation.

RESULTS

We found significant 2-way interactions (ANOVA, P<0.05) between the analyzed regions of the target muscles dependent on the time of measurement, that is, before and during a complete blocking of neuromuscular transmission. These effects could be demonstrated for each target muscle separately.

DISCUSSION

An increased muscle tension in MTPs, and not a primary local inflammation with enhanced viscoelasticity, was the main result of our investigation. We interpret this increased muscular tension in the taut band with an MTP as increased spinal segmental excitability. In line with this, we assume a predominant, but not unique, impact of increased spinal excitability resulting in an augmented tension of segmental-associated muscle fibers for the etiology of MTP. Consequently, postisometric relaxation might be a promising therapeutic option for MTPs.