Echo-intensity and fatty infiltration ultrasound imaging measurement of cervical multifidus and short rotators in healthy people: A reliability study

Muscle ultrasound and its application to point-of-care ultrasonography: a narrative review

Technological advances of hand-held ultrasound devices and educational programmes for their use, such as point-of-care ultrasonography (POCUS) training, have contributed to the increasing application of these devices in clinical practice. With the greater impact of frailty and sarcopenia in aging societies, attention is being focused on the use of ultrasound for skeletal muscle assessment. In this narrative review, we discuss how ultrasound can be applied to skeletal muscle assessment, especially that of the quadriceps muscle, in clinical practice. Muscle thickness by ultrasound has been shown to have good reliability and validity for the evaluation of muscle size, and echo intensity has been used to evaluate muscle quality. Muscle ultrasound has not only been useful to diagnose sarcopenia in various settings, but has also been validated to predict health-related outcomes such as death and functional disability. Recommended methods for muscle ultrasound was published recently, and the results of future studies are expected to be comparable. Although several challenging issues with muscle ultrasound remain, if it could be incorporated into educational programmes such as POCUS training, more clinicians may be able to use ultrasound for skeletal muscle assessment in the future.KEY MESSAGESThe evolution of hand-held ultrasound devices enables physicians to perform ultrasound at the bedside as part of regular medical examinations.Muscle ultrasound is considered an effective tool for evaluating muscle size and quality, and has been studied in various settings.More clinicians may be able to evaluate skeletal muscle assessment with the development of educational programmes on muscle ultrasound in the future.

Convergent Validity between Electromyographic Muscle Activity, Ultrasound Muscle Thickness and Dynamometric Force Measurement for Assessing Muscle

Muscle fatigue is defined as a reversible decline in performance after intensive use, which largely recovers after a resting period. Surface electromyography (EMG), ultrasound imaging (US) and dynamometry are used to assess muscle activity, muscle morphology and isometric force capacity. This study aimed to assess the convergent validity between these three methods for assessing muscle fatigue during a manual prehension maximal voluntary isometric contraction (MVIC). A diagnostic accuracy study was conducted, enrolling 50 healthy participants for the measurement of simultaneous changes in muscle thickness, muscle activity and isometric force using EMG, US and a hand dynamometer, respectively, during a 15 s MVIC. An adjustment line and its variance (R²) were calculated. Muscle activity and thickness were comparable between genders (p > 0.05). However, men exhibited lower force holding capacity (p < 0.05). No side-to-side or dominance differences were found for any variable. Significant correlations were found for the EMG slope with US (r = 0.359; p < 0.01) and dynamometry (r = 0.305; p < 0.01) slopes and between dynamometry and US slopes (r = 0.227; p < 0.05). The sample of this study was characterized by comparable muscle activity and muscle thickness change between genders. In addition, fatigue slopes were not associated with demography or anthropometry. Our findings showed fair convergent associations between these methods, providing synergistic muscle fatigue information.

Inter-Examiner Disagreement for Assessing Cervical Multifidus Ultrasound Metrics Is Associated with Body Composition Features

Ultrasound imaging (US) is a biosensing technique that is widely used in several healthcare disciplines (including physiotherapy) for assessing multiple muscle metrics, such as muscle morphology and quality. Since all biosensors need to be tested in order to demonstrate their reliability, accuracy, sensitivity, and specificity, identifying factors that affect their diagnostic accuracy is essential. Since previous studies analyzed the impact of sociodemographic but not body composition characteristics in US errors, this study aimed to assess whether body composition metrics are associated with ultrasound measurement errors. B-mode images of the lumbar multifidus muscle at the L5 level were acquired and analyzed in 47 healthy volunteers by two examiners (one experienced and one novice). The cross-sectional area, muscle perimeter, and mean echo intensity were calculated bilaterally. A correlation analysis and a multivariate linear regression model were used for assessing the inter-examiner differences with respect to body composition metrics. The results demonstrated good-to-excellent reliability estimates for the cross-sectional area, muscle perimeter, aspect ratio, roundness, circularity, and mean brightness metrics (all ICC > 0.85). However, solidity showed unacceptable reliability (ICC < 0.7). Age, height, total lean mass, trunk lean mass, and water volume were associated with inter-examiner disagreement on mean echo intensity. Cross-sectional area, perimeter, and roundness measurement errors were associated with lean mass and water volume.

Identifying Demographic, Clinical, Muscular and Histological Factors Associated with Ultrasound Cervical Multifidus Measurement Errors in a Chronic Neck Pain Population

Ultrasound imaging (US) is a widely used imaging tool in physiotherapy for assessing muscle morphology and quality, among other purposes, such as ensuring the patients’ safety during invasive procedures or providing visual feedback during motor control exercises. Identifying factors associated with measurement errors is essential to target avoid bias in high-risk of bias populations. Therefore, this study aimed to assess whether demographic, clinical, muscular and histological factors are associated with ultrasound measurement errors in patients with idiopathic chronic neck pain. B-mode images were acquired and analyzed in 126 patients with chronic neck pain by two experienced examiners. Cross-sectional area, muscle perimeter, mean echo intensity and percentage of fatty infiltration were analyzed. The interexaminer agreement was assessed by calculating the absolute error, intraclass correlation coefficient (ICC), standard error of measurement (SEM) and minimal detectable changes (MDC). A Pearson’s correlation matrix including all variables was calculated to conduct a multivariate linear stepwise regression model for estimating the explained variance for each measurement error. Results demonstrated excellent reliability (ICC = 0.965) for assessing the cross-sectional area, and good reliability for assessing the muscle perimeter, mean echo intensity and intramuscular infiltrates estimation (ICC = 0.898, 0.882 and 0.758, respectively). Although clinical variables were not associated with measurement errors (p > 0.05), multiple correlations were found between demographic and cervical multifidus characteristics with measurement errors.

Sonographic Comparison of Neck Extensor Muscle Thickness of Ankylosing Spondylitis and Non-radiographic Axial Spondyloarthritis Patients with Healthy Volunteers

Introduction This study examines the neck extensor muscle thickness of patients with ankylosing spondylitis (AS) and non-radiographic axial spondyloarthritis (nr-axSpA) by comparing them with healthy volunteers. It also aims to evaluate the relationship between muscle thickness and disease activity, functional parameters, neck disability and quality of life in patients with AxSpA.

Method In this cross-sectional study, 30 patients with AS and 30 patients with nr-AxSpA who were admitted to a Physical Medicine and Rehabilitation outpatient clinic were included consecutively. Thirty healthy participants were included as a control group. The thickness of muscles was measured bilaterally by ultrasound and the muscle thickness average was recorded. All patients with axSpA were asked to complete the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), the Bath Ankylosing Spondylitis Functional Index (BASFI), the Bath Ankylosing Spondylitis Metrology Index (BASMI), the Ankylosing spondylitis Quality of Life (AsQoL) scale and the Neck Disability Index (NDI).

Results Mean patient age was 42.36±10.0 in the AS group, 38.13±7.94 in the nr-axSpA group and 39.06±8.25 in the healthy group. A statistically significant decrease was found in multifidus, semispinalis capitis, semispinalis cervicis and splenius capitis muscle thickness in AS patients compared with the healthy group, and in semispinalis cervicis muscle thickness in nr-axSpA patients compared with the healthy group. However, when trapezius muscle thickness was compared between the groups, no statistical difference was found. There was a significant negative correlation between neck extensor muscle thickness and age, BASDAI, NDI and AsQoL in patients with axSpA.

Conclusion The thickness of the neck extensor muscles is decreased in patients with AxSpA compared with healthy individuals, and this situation can be reliably detected by ultrasound.

Ultrasound assessment of deep cervical extensors morphology and quality in populations with whiplash associated disorders: An intra- and inter-examiner reliability study

BACKGROUND

Ultrasound imaging (US) has shown to be a reliable and valid tool for assessing muscle morphology and quality. However, most studies have focused on asymptomatic populations.

OBJECTIVE

To investigate intra- and inter-rater reliability estimates of muscle morphology and quality of cervical multifidus (CM) and short rotators (SR) in patients with whiplash associated disorders (WAD).

DESIGN

An intra- and inter-examiner reliability study.

METHODS

US images were acquired in a blinded fashion in 34 patients (35% males) by two experienced and two novice examiners. Cross-sectional area (CSA), perimeter, mean echo-intensity (EI) and the percentage of fatty infiltration were assessed twice, one-week apart, in a randomized order. Reliability estimates (i.e., intra-class correlation coefficients -ICC-, standard error of measurement -SEM-, minimal detectable change, mean of measurements, absolute and percent errors) were calculated.

RESULTS

Intra-examiner reliability for experienced assessors ranged from good to excellent for CM and SR (ICC_3,1 = 0.888-0.975 and 0.810-0.964 respectively) and from moderate-to-good for novices (ICC_3,1 = 0.708-0.790 and 0.655-0.796 respectively). The agreement between the experienced examiners was moderate to good (ICC_3,2 = 0.737-0.899 and 0.728-0.899 CM and SR respectively); between novice and experienced examiners was moderate to good (ICC_3,2 = 0.617-0.873 and 0.657-0.766 CM and SR respectively); and between novice examiners was moderate-to-good for CM (ICC_3,2 = 0.610-0.777) and moderate for SR (ICC_3,2 = 0.600-0.730).

CONCLUSION

CM and SR intra-examiner reliability was good-to-excellent for novice and experienced examiners. However, inter-examiner reliability was clinically acceptable just for experienced examiners at the C4/C5 level in WAD populations.

Sonographic measurement of the neck extensor muscle thickness in patients with fibromyalgia

OBJECTIVE

The aim of this cross-sectional study was to compare cervical extensor muscle thickness measurements in patients with fibromyalgia (FM) with chronic neck pain and an asymptomatic control group, and to examine the relationship between cervical extensor muscle thickness and pain, quality of life, and disability.

METHODS

The study included 41 patients with FM and 41 asymptomatic control subjects. The thickness of the cervical extensor muscles (multifidus, semispinalis capitis, semispinalis cervicis, splenius capitis and trapezius muscles) was evaluated with ultrasonography. The severity of FM was evaluated with the Fibromyalgia Impact Questionnaire (FIQ), neck disability with the Neck Disability Index (NDI) and pain severity with a Numeric Rating Scale (NRS).

RESULTS

The mean sonographic thickness values of all the neck extensor muscles were significantly decreased in the FM group compared with the control group (p < 0.001). There were negative correlations between the FIQ and multifidus, splenius capitis and trapezius thickness values. NDI was significantly negatively correlated with multifidus and trapezius thickness. There was no significant correlation between neck extensor muscle thickness and age, duration of FM, and NRS scores.

CONCLUSION

This study demonstrated a decrease in cervical extensor muscle thickness in patients with FM with chronic neck pain. Cervical extensor muscle morphologies should be considered by the clinician when planning treatment in patients with FM with neck pain.

Cervical Multifidus Morphology and Quality is not Associated with Clinical Variables in Women with Fibromyalgia: An Observational Study

OBJECTIVE

Some studies have reported the presence of histological alterations such as myofibers disorganization and abnormalities in the number and shape of mitochondria in patients with fibromyalgia syndrome (FMS). Although Ultrasound imaging (US) is used to quantitatively characterize muscle tissues, US studies in patients with FMS are lacking. Therefore, we aimed to describe morphological and qualitative cervical multifidus (CM) muscle US features in women with FMS and to assess their correlation with clinical indicators.

DESIGN

Observational study.

SETTING

AFINSYFACRO Fibromyalgia Association (Madrid, Spain).

SUBJECTS

Forty-five women with FMS participated.

METHODS

Sociodemographic (e.g., age, height, weight, and BMI), clinical (e.g., pain -NPRS-, evolution time, related-disability -FIQ-) outcomes were collected. Images were acquired bilaterally at the cervical spine (C4-C5 level) and measured by an experienced examiner for assessing muscle morphology (e.g., cross-sectional area -CSA-, perimeter and shape) and quality (mean echo-intensity -EI- and intramuscular fatty infiltration -FI-). Side-to-side comparisons and a correlational analysis were conducted.

RESULTS

No significant side-to-side differences were found for morphology nor quality features (P > 0.05). None of the clinical indicators were associated with US characteristics (all, P > 0.05).

CONCLUSION

Our results showed no side-to-side differences for CM morphology and quality as assessed with US. No associations between CM muscle morphology nor quality with FIQ, PPT, NPRS nor evolution time were observed. Our preliminary data suggest that muscle morphology is not directly related to pain and related-disability in women with FMS.

Ultrasound Imaging as a Visual Biofeedback Tool in Rehabilitation: An Updated Systematic Review

Rehabilitative ultrasound imaging (RUSI) is used by physical therapists as a feedback tool for measuring changes in muscle morphology during therapeutic interventions such as motor control exercises (MCE). However, a structured overview of its efficacy is lacking. We aimed to systematically review the efficacy of RUSI for improving MCE programs compared with no feedback and other feedback methods. MEDLINE, PubMed, SCOPUS and Web of Science databases were searched for studies evaluating efficacy data of RUSI to improve muscular morphology, quality, and/or function of skeletal muscles and MCE success. Eleven studies analyzing RUSI feedback during MCE were included. Most studies showed acceptable methodological quality. Seven studies assessed abdominal wall muscles, one assessed pelvic floor muscles, one serratus anterior muscle, and two lumbar multifidi. Eight studies involved healthy subjects and three studies clinical populations. Eight studies assessed muscle thickness and pressure differences during MCE, two assessed the number of trials needed to successfully perform MCE, three assessed the retain success, seven assessed the muscle activity with electromyography and one assessed clinical severity outcomes. Visual RUSI feedback seems to be more effective than tactile and/or verbal biofeedback for improving MCE performance and retention success, but no differences with pressure unit biofeedback were found.

Echo-intensity, fatty infiltration, and morphology ultrasound imaging assessment in healthy and whiplash associated disorders populations: an observational study

BACKGROUND

Although changes in muscle morphology and quality in deep neck flexors seem to be clear in patients with whiplash-associated disorders (WAD), evidence for deep neck extensors is heterogeneous. In addition, most studies have used magnetic resonance imaging or computer tomography, which is not available for regular practice.

OBJECTIVES

To assess differences in deep neck extensors morphology and quality between patients with WAD and controls with ultrasound imaging (US) and to assess the association of imaging findings with clinical features.

METHODS

One hundred and sixty brightness-mode images at C4/C5 level were acquired in 41 patients with WAD and 39 pain-free controls. Muscle morphology and quality characteristics of the cervical multifidus (CM) and short rotators (SR), clinical pain features and pressure pain thresholds (PPT) were assessed in a blinded design.

RESULTS

Between-groups differences in both CM and SR were observed for fatty infiltration percentage (mean: 4.9%; P < 0.001; mean: 3.5%; P < 0.05, respectively) and mean EI (mean: 4.1; P < 0.001; mean: 3.2; P < 0.05, respectively): patients exhibited higher fatty infiltration than controls. The intensity of neck pain was negatively associated with multifidus CSA and perimeter (P < 0.001); symptoms duration was negatively associated with CM morphology (P < 0.001), CM mean EI (P < 0.05) and SR morphology (P < 0.05); pain-related disability was associated with CM morphology (P < 0.001) and SR mean EI (P < 0.05); and PPTs was associated with CM mean EI (P < 0.01) and FI (p < 0.05) and SR morphology (P < 0.001). No significant effect of gender was found in any analysis.

CONCLUSION

US assessment of deep cervical extensors revealed greater fatty infiltration, but no differences in muscle morphology, between WAD patients and pain-free controls.