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Ultrasound Imaging in the Diagnosis of Muscle Disease
Abstract
A comparative study has been done of the static B-scan ultrasound appearance of the quadriceps muscle of the thigh in 60 new patients attending our muscle clinic and in 60 control children. In the control subjects there was good visualization of bone and fascia, which stood out clearly against the background of echo-free muscle tissue. Striking change was found in children with neuromuscular disease. Muscular dystrophies were associated with an increase in the intensity of echo reflected from the muscle substance, with corresponding loss of bone echo. Spinal muscular atrophies and neuropathies also showed an increase in muscle echo along with atrophy of the muscle and increase in depth of subcutaneous tissue. Various congenital myopathies also showed changes. Infants with hypotonia from nonneuromuscular causes had normal scans. Severity of change on the scan did not relate to functional disability, and some children had good function yet strikingly abnormal scans. Three degree of change on the scan correlated with the degree of disruption of muscle architecture on biopsy. Ultrasound imaging has proved to be a useful, noninvasive screening tool in the investigation of children with neuromuscular disease.
... • Gray Scale (B-Mode): The examined area was classified as presenting preserved architecture (when its "feather pattern" aspect was preserved) or altered (when it presented any change to the normal pattern), as shown at the Fig. 1 [21]. A new classification was performed (semi-quantitative assessment), on a scale from 1 to 4, that represents the number of echoes displayed in the gray scale image, using the echogenicity of the cortical bone as a visual reference [21]. ...
... • Gray Scale (B-Mode): The examined area was classified as presenting preserved architecture (when its "feather pattern" aspect was preserved) or altered (when it presented any change to the normal pattern), as shown at the Fig. 1 [21]. A new classification was performed (semi-quantitative assessment), on a scale from 1 to 4, that represents the number of echoes displayed in the gray scale image, using the echogenicity of the cortical bone as a visual reference [21]. The musculature was graded as: Grade 1, when it presented an architectural pattern "in feather", that is, without invasion of the muscle by fat and/or connective tissue (normal for purposes of statistical analysis); Grade 2, when there was any invasion of the musculature by fat and/or connective tissue (moderate alteration); Grade 3, when the muscle presented more evident alterations, with some rupture of muscle fascicles (important alteration); and Grade 4, in the presence of severe alteration, with replacement of 50% or more of muscle by fat and/or connective tissue (important alteration). ...
... These findings were attributed to the presence of edema in the initial phase of the disease and to fatty infiltration in the follow up [9]. Although our study showed an increase in echogenicity [21] (through the semi-quantitative gray scale) in deltoids, biceps brachii and quadriceps femoris muscles of patients considered to have disease activity, we cannot infer at which stage of the disease they were. The qualitative gray scale, where the loss of normal muscle architecture was assessed, did not show significant differences between active and inactive disease. ...
Background
Juvenile Dermatomyositis (JDM) is the most common idiopathic inflammatory myopathy in children. Imaging exams are useful for muscle assessment, with ultrasonography (US) being a promising tool in detecting disease activity and tissue damage. There are few studies about muscle elastography.
Objectives
Our aim was to associate clinical, laboratory, and nailfold capillaroscopy (NC) assessments with US in JDM patients; and to compare the findings of US and Strain Elastography (SE) from patients and healthy controls.
Methods
An analytic cross-sectional study was performed with JDM patients and healthy controls. Patients underwent clinical exam to access muscle strength and completed questionnaires about global assessment of the disease and functional capacity. Patients were submitted to NC and measurement of muscle enzymes. All subjects underwent US assessment, using gray scale, Power Doppler (PD), and SE.
Results
Twenty-two JDM patients and fourteen controls, aged between 5 and 21 years, matched for age and sex were assessed. In qualitative and semi-quantitative gray scale, we observed a higher frequency of alterations in patients (p < 0.001), while in PD, there was a higher frequency of positivity in patients’ deltoids and anterior tibialis (p < 0.001). Active disease was associated with an important change in the semi-quantitative gray scale in deltoids (p = 0.007), biceps brachii (p = 0.001) and quadriceps femoris (p = 0.005). The SE demonstrated a high negative predictive value of 87.2.
Conclusion
US was able, through gray scale, to differentiate JDM patients from controls, while PD achieved such differentiation only for deltoids and anterior tibialis. The semi-quantitative gray scale showed disease activity in proximal muscles. SE was not able to differentiate patients from controls.
... • Gray Scale (B-Mode): The examined area was classi ed as presenting preserved architecture (when its "feather pattern" aspect was preserved) or altered (when it presented any change to the normal pattern), as shown at the Fig. 1 [22]. A new classi cation was performed (semi-quantitative assessment), on a scale from 1 to 4, that represents the number of echoes displayed in the gray scale image, using the echogenicity of the cortical bone as a visual reference [22]. ...
... • Gray Scale (B-Mode): The examined area was classi ed as presenting preserved architecture (when its "feather pattern" aspect was preserved) or altered (when it presented any change to the normal pattern), as shown at the Fig. 1 [22]. A new classi cation was performed (semi-quantitative assessment), on a scale from 1 to 4, that represents the number of echoes displayed in the gray scale image, using the echogenicity of the cortical bone as a visual reference [22]. The musculature was graded as: Grade 1, when it presented an architectural pattern "in feather", that is, without invasion of the muscle by fat and/or connective tissue (normal for purposes of statistical analysis); Grade 2, when there was any invasion of the musculature by fat and/or connective tissue (moderate alteration); Grade 3, when the muscle presented more evident alterations, with some rupture of muscle fascicles (important alteration); ...
... These ndings were attributed to the presence of edema in the initial phase of the disease and to fatty in ltration in the follow up [9]. Although our study showed an increase in echogenicity [22] (through the semi-quantitative gray scale) in deltoids, biceps brachii and quadriceps femoris muscles of patients considered to have disease activity, we cannot infer at which stage of the disease they were. The qualitative gray scale, where the loss of normal muscle architecture was assessed, did not show signi cant differences between active and inactive disease. ...
Background
Juvenile Dermatomyositis (JDM) is the most common idiopathic inflammatory myopathy in children. Imaging exams are useful for muscle assessment, with ultrasonography (US) being a promising tool in detecting disease activity and tissue damage. There are few studies about muscle elastography.
Objectives
Our aim was to associate clinical, laboratory, and nailfold capillaroscopy (NC) assessments with US in JDM patients; and to compare the findings of US and Strain Elastography (SE) from patients and healthy controls.
Methods
Twenty-two JDM patients and fourteen controls, aged between 5 and 21 years, matched for age and sex were enrolled. Patients underwent clinical exam to access muscle strength and completed questionnaires about global assessment of the disease and functional capacity. Patients were submitted to NC and measurement of muscle enzymes. All subjects underwent US assessment, using gray scale, Power Doppler (PD), and SE.
Results
In qualitative and semi-quantitative gray scale, we observed a higher frequency of alterations in patients (p < 0.001), while in PD, there was a higher frequency of positivity in patients' deltoids and anterior tibialis (p < 0.001). Active disease was associated with an important change in the semi-quantitative gray scale in deltoids (p = 0.007), biceps brachii (p = 0.001) and quadriceps femoris (p = 0.005). The SE demonstrated a high negative predictive value of 87.2.
Conclusion
US was able, through gray scale, to differentiate JDM patients from controls, while PD achieved such differentiation only for deltoids and anterior tibialis. The semi-quantitative gray scale showed disease activity in proximal muscles. SE was not able to differentiate patients from controls.
... It has been shown to be a practical and reliable alternative to more invasive techniques such as electromyography (EMG) and muscle MRI [19] and is able to detect early skeletal muscle abnormalities [20]. The sensitivity of muscle ultrasound to detect a neuromuscular disorder is about 70% using a qualitative analysis, but can be increased up to 92% when using a quantified approach [21][22][23]. ...
... Visual analysis with a semi-quantitative grading was performed of each muscle scanned using the Heckmatt rating scale (HRS) [22]: ...
... For none of the muscles included in the study protocol the mean z-scores were statistically significant lower compared to 0. The mean z-scores of the biceps brachii (z = 1.45; P < 0.001), biceps femoris (z = 0.43; P = 0.002), deltoid (z = 0.31; P = 0.009), trapezius (z = 0.38; P = 0.010) and the sum of all muscles (z = 0.40; P < 0.001) were significantly higher Table 2 Qualitative analysis of muscle ultrasound studies and neuromuscular symptoms from all study participants (n = 40) Patient ID 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 specific sum score 18 20 26 21 20 22 22 23 27 18 20 18 21 26 18 19 25 21 27 18 18 18 31 27 18 27 27 18 37 23 21 18 19 26 24 20 24 31 15 Summary of neuromuscular symptoms, the Heckmatt rating scale, [22] patient specific Heckmatt rating scale sum score and muscle specific Heckmatt rating scale sum score. The patient specific Heckmatt rating scale sum score for patient 34 and patient 40 are incomplete due to missing data. ...
Background:
Variants in RYR1, the gene encoding the ryanodine receptor-1, can give rise to a wide spectrum of neuromuscular conditions. Muscle imaging abnormalities have been demonstrated in isolated cases of patients with a history of RYR1-related malignant hyperthermia (MH) susceptibility.
Objective:
To provide insights into the type and prevalence of muscle ultrasound abnormalities and muscle hypertrophy in patients carrying gain-of-function RYR1 variants associated with MH susceptibility and to contribute to delineating the wider phenotype, optimizing the diagnostic work-up and care for of MH susceptible patients.
Methods:
We performed a prospective cross-sectional observational muscle ultrasound study in patients with a history of RYR1-related MH susceptibility (n = 40). Study procedures included a standardized history of neuromuscular symptoms and a muscle ultrasound assessment. Muscle ultrasound images were analyzed using a quantitative and qualitative approach and compared to reference values and subsequently subjected to a screening protocol for neuromuscular disorders.
Results:
A total of 15 (38%) patients had an abnormal muscle ultrasound result, 4 (10%) had a borderline muscle ultrasound screening result, and 21 (53%) had a normal muscle ultrasound screening result. The proportion of symptomatic patients with an abnormal result (11 of 24; 46%) was not significantly higher compared to the proportion of asymptomatic patients with an abnormal ultrasound result (4 of 16; 25%) (P = 0.182). The mean z-scores of the biceps brachii (z = 1.45; P < 0.001), biceps femoris (z = 0.43; P = 0.002), deltoid (z = 0.31; P = 0.009), trapezius (z = 0.38; P = 0.010) and the sum of all muscles (z = 0.40; P < 0.001) were significantly higher compared to 0, indicating hypertrophy.
Conclusions:
Patients with RYR1 variants resulting in MH susceptibility often have muscle ultrasound abnormalities. Frequently observed muscle ultrasound abnormalities include muscle hypertrophy and increased echogenicity.
... Además de la medición de la pérdida de la cantidad muscular, mediante la adquisición de imágenes ecográficas se logra la valoración de la eco-intensidad, que corresponde al método establecido para evaluar la calidad del músculo 6,8 , siendo un potencial marcador del estado del tejido muscular 10 . Una de las alternativas para ponderar la eco-intensidad es mediante la escala Heckmatt desarrollada por Heckmatt y Dubowitz, quienes propusieron esta escala en base al criterio cualitativo para valorar el músculo 11 . ...
... Los modelos fueron evaluados en posición supina con extensión pasiva de la extremidad inferior y evitando rotaciones, siguiendo un protocolo de medición previamente reportado (15) . Segundo, cada evaluador novato calificó la eco-intensidad de 19 imágenes ecográficas musculares usando la escala Heckmatt 11 . La escala Heckmatt califica la eco-intensidad muscular en base a 4 grados: 1) eco-intensidad normal; 2) eco-intensidad muscular aumentada con reflejo óseo normal, 3) eco-intensidad muscular aumentada con reflejo óseo reducido y 4) eco-intensidad muscular notablemente aumentada con pérdida del reflejo óseo. ...
Rev Med Chile 2023; 151: 1153-1163
Muscle ultrasound: reliability across experience levels in critical care physiotherapists Background: Muscle ultrasound is a valid tool to monitor muscle mass loss in critically ill patients. The level of experience is essential to the accuracy of the measurements. Aim: To evaluate the interobserver reliability of experienced and novice raters measuring muscle thickness and echo intensity of the quadriceps and tibialis anterior. Material and Methods: Cross-sectional observational study. Twenty-four critical care physiotherapists participated (5 experienced and 19 novice). Following a standardized ultrasound protocol, each rater measured the thickness (centimeters) of the quadriceps and tibialis anterior of 10 healthy and young models using linear and convex probes of portable devices. The Intraclass Correlation Coefficient and the Minimal Detectable Change (95% confidence interval) were calculated. Additionally, the novices scored the echo intensity of 19 muscle ultrasound images of critically ill patients using the Heckmatt score (qualitative assessment). The agreement with experienced raters was evaluated (Spearman Rho). Results: 960 muscle thickness measurements were performed (experienced = 200 and novice = 760). The mean thickness of the quadriceps and tibialis anterior was 4.4 ± 0.77 and 2.4 ± 0.35 centimeters for the experienced and 4.2 ± 0.80 and 2.2 ± 0.39 centimeters for the novices, respectively. Quadriceps' and tibialis' anterior reliability were 0.82 and 0.86 for experienced and 0.76 and 0.41 for novices, respectively. The Minimal Detectable Change ranged from 0.14-0.33 centimeters. The mean Heckmatt score was 2.6 ± 0.83 points, with a reliability of 0.68 and an agreement with the experimenters of 0.78 [p < 0.001]. Conclusions: Interobserver reliability was excellent for experienced raters and moderate to good for novice raters. The level of experience could determine the reliability of the results. (Rev Med Chile 2023; 151: 1153-1163)
... With the appearance of these new systems in the 1980s, the applications to the MSK system started to appear at a greater frequency in the imaging literature. Examination of articular cartilage, joint effusions, synovitis, tendon and muscle abnormalities, and nerve imaging using grayscale ultrasound were described, including the first descriptions of tendon morphology and anisotropy (20)(21)(22)(32)(33)(34)(35)(36)(37)(38)(39)(40)(41)(42)(43)(44)(45)(46) . Multiple anatomic locations were accessible to this modality, resulting in studies of the Achilles tendon, patellar tendon, and soon also more complex anatomical areas such as the rotator cuff (22,(39)(40) (Fig. 5, Fig. 6, Fig. 7). ...
... Multiple anatomic locations were accessible to this modality, resulting in studies of the Achilles tendon, patellar tendon, and soon also more complex anatomical areas such as the rotator cuff (22,(39)(40) (Fig. 5, Fig. 6, Fig. 7). Early assessment of muscle hematomas and soft tissue masses using bistable techniques expanded to more sophisticated descriptions of muscle and other soft tissue pathology (26)(27)(28)(29)(30)33,36) . Large joints, such as the knee and hip, were ultimately expanded to include small joint pathology, such as in the hands and feet (41,45) . ...
During the past four decades, musculoskeletal ultrasound has become popular as an imaging modality due to its low cost, accessibility, and lack of ionizing radiation. The development of ultrasound technology was possible in large part due to concomitant advances in both solid-state electronics and signal processing. The invention of the transistor and digital computer in the late 1940s was integral in its development. Moore’s prediction that the number of microprocessors on a chip would grow exponentially, resulting in progressive miniaturization in chip design and therefore increased computational power, added to these capabilities. The development of musculoskeletal ultrasound has paralleled technical advances in diagnostic ultrasound. The appearance of a large variety of transducer capabilities and rapid image processing along with the abil- ity to assess vascularity and tissue properties has expanded and continues to expand the role of musculo- skeletal ultrasound. It should also be noted that these developments have in large part been due to a number of individuals who had the insight to see the potential applications of this developing technology to a host of relevant clinical musculoskeletal problems. Exquisite high-resolution images of both deep and small super- ficial musculoskeletal anatomy, assessment of vascularity on a capillary level and tissue mechanical proper- ties can be obtained. Ultrasound has also been recognized as the method of choice to perform a large variety of interventional procedures. A brief review of these technical developments, the timeline over which these improvements occurred, and the impact on musculoskeletal ultrasound is presented below.
... Muscle echogenicity. RF and VI muscles echogenicity was assessed using a modified version of the Heckmatt scale (13). This modified visual semiquantitative scale, which was recently developed by our research group, grades muscle echogenicity from 0 to 3, where 0=normal (normal hypoechoic muscle), 1=mild (homogeneously distributed overall increase of the echogenicity involving ≤ 1/3 of the entire muscle tissue), 2=moderate (homogeneously distributed overall increase of the echogenicity involving >1/3 but ≤2/3 of the entire muscle tissue) and 3=severe (homogeneously distributed overall increase of the echogenicity involving >2/3 of the entire muscle tissue) (11,14). ...
... In our previous study (11), we proposed a novel visual semi-quantitative scale for muscle echogenicity assessment, which was developed taking as reference the Heckmatt scale (13). This scale was developed by Heckmatt in 1982 in pediatric patients with neuromuscular disorders, and has been the reference method for evaluating muscle echogenicity for several years (13). Unlike the Heckmatt scale, which evaluates the degree of echo-intensity in a muscle area, our modified visual scale incorporates the extent of the muscular tissue showing an increased echogenicity. ...
Objectives
The aim was to explore the inter-reliability of a newly developed US scanning protocol (multimodal US) for the assessment of different aspects of sarcopenia-related muscle involvement, including muscle mass, muscle quality and muscle stiffness [using point shear-wave elastography (SWE)], in patients with rheumatic and musculoskeletal diseases (RMDs).
Methods
Quadriceps muscle mass (i.e. muscle thickness), muscle quality (i.e. muscle echogenicity evaluated with both a visual semi-quantitative scale and a dedicated software package for image analysis, ImageJ) and point SWE measurements were obtained by two rheumatologists (blinded to each other’s evaluation) in consecutive RMD patients without previous/current myositis or neuromuscular disorders.
Inter-reliability was assessed using the intraclass correlation coefficient (ICC) for continuous variables and Cohen’s kappa (κ) for categorical variables.
Results
A total of 45 RMD patients were enrolled [mean age 54.5 (16.0) years, male-to-female ratio 1:1.5, mean BMI 24.6 (4.6) kg/m2], 10 with PsA, 7 RA, 5 AS, 5 PMR, 4 SLE, 4 gout, 4 OA, 3 FM and 3 SSc. The grade of inter-rater reliability was excellent for muscle mass [ICC = 0.969 (0.953 < ICC < 0.979)]. Regarding muscle echogenicity, the agreement was substantial/almost perfect using the visual semi-quantitative scale (weighted linear = 0.793, weighted squared = 0.878) and excellent using ImageJ analysis [ICC = 0.916 (0.876 < ICC < 0.944)]. Finally, a good agreement was obtained for point SWE measurements [ICC = 0.76 (0.712 < ICC < 0.8)].
Conclusion
Multimodal US is a novel and reliable tool for the evaluation of different aspects of muscle involvement (muscle mass, muscle quality and muscle stiffness) in RMD patients.
... For visual grading the most widely used scale is the Heckmatt scale (Table 3, Fig. 2). 25 For digitized analysis MATLAB based software or the standard histogram function of Adobe Photoshop (Adobe systems Inc., San Jose, CA, USA) has been applied. 26,27 Qualitative and quantitative assessment of Depending on entity (focal or generalized) ...
... echo-intensity of the muscle with normal echo-intensity and full visualization of the adjacent bone cortex Grade 2 Moderately increased echo-intensity of the muscle and distinct bone echo with normal echo-intensity and full visualization of the adjacent bone cortex Grade 3 Markedly increased echo-intensity of the muscle and reduced bone echo with altered echo-signal and incomplete visualization of the adjacent bone cortex Grade 4 Strongly increased echo-intensity of the muscle with complete loss of bone cortex echo-signal.Scale proposed by Heckmatt et al.25 ...
Muscle ultrasound (MUS) is increasingly used by neurologists, neuropediatricians, neurosurgeons, specialized radiologists and anaesthesiologists for the imaging-supported diagnosis of neuromuscular disorders. Especially, MUS is highly sensitive in detecting fasciculations in motor neuron diseases, and in revealing intensive care unit acquired weakness. Hereditary and inflammatory myopathies are associated with distinct patters of echo-intensity changes of affected muscles. Moreover, MUS can be used for guiding needle biopsy of muscle lesions, and for targeting intramuscular botulinum neurotoxin (BoNT) injection in neurological disorders with muscle hyperactivity. MUS-guidance of BoNT injection is especially recommendable in complex cervical dystonia, in task-related hand dystonia (writer’s cramp, musician dystonia), and in children and adolescents with cerebral palsy. Modern ultrasound technologies such as sono-elastography, tissue Doppler, and high-definition microvasculature imaging allow for novel diagnostic and therapeutic uses. Recently, an international expert group reported consensus guidelines for neuromuscular ultrasound training. The present review provides a concise overview of well-established diagnostic and therapeutic applications of MUS in clinical neurology, with specific focus at MUS for targeting intramuscular BoNT injections.
... Another method to assess ME is semi-quantitative grading using the Heckmatt Scale (Figure 3). Introduced by Heckmatt and coworkers in 1982, this four-point scale relies on the visual assessment of ME and bone echotexture [82]. The brighter the muscle and the lower the bone echogenicity, the higher the grading. ...
... Another method to assess ME is semi-quantitative grading using the Heckmatt Scale ( Figure 3). Introduced by Heckmatt and coworkers in 1982, this four-point scale relies on the visual assessment of ME and bone echotexture [82]. The brighter the muscle and the lower the bone echogenicity, the higher the grading. ...
Intensive care unit-acquired weakness (ICUAW) is one of the most common causes of muscle atrophy and functional disability in critically ill intensive care patients. Clinical examination, manual muscle strength testing and monitoring are frequently hampered by sedation, delirium and cognitive impairment. Many different attempts have been made to evaluate alternative compliance-independent methods, such as muscle biopsies, nerve conduction studies, electromyography and serum biomarkers. However, they are invasive, time-consuming and often require special expertise to perform, making them vastly impractical for daily intensive care medicine. Ultrasound is a broadly accepted, non-invasive, bedside-accessible diagnostic tool and well established in various clinical applications. Hereby, neuromuscular ultrasound (NMUS), in particular, has been proven to be of significant diagnostic value in many different neuromuscular diseases. In ICUAW, NMUS has been shown to detect and monitor alterations of muscles and nerves, and might help to predict patient outcome. This narrative review is focused on the recent scientific literature investigating NMUS in ICUAW and highlights the current state and future opportunities of this promising diagnostic tool.
... 13,14 Muscle thickness (MT) and echo intensity (EI), an indicator of muscle quality, are related to muscle strength, physical function, and muscle mass measured using DXA or BIA. [15][16][17][18][19][20][21] The assessment of muscle quality is gaining increasing attention as a potentially more critical metric than simple muscle mass measurements. 22 Previous studies suggest that muscle quality may deteriorate before muscle mass and is independently associated with physical performance and survival. ...
... [26][27][28] The higher numerical value of EI reflects more fat and fibrous tissue in the body. 29,30 The majority of reports on muscle US have used the quadriceps femoris muscle (QFM) for measurement purposes, [13][14][15][16][17][18][19][20][21]26,27 but when performing QFM US in practice, it is necessary to expose and image the part above the knee, which makes it difficult to perform QFM US easily in clinical settings. To solve this problem, we previously investigated a method that uses the tibialis anterior muscle (TA) to determine whether US of this easier-to-approach site is useful to diagnose sarcopenia and evaluate muscle quality. ...
Purpose
Muscle mass, a key index for the diagnosis of sarcopenia, is currently assessed using the appendicular skeletal muscle mass index (ASMI) by bioelectrical impedance analysis (BIA). Muscle thickness (MT) assessed by ultrasonography (US) may be a better determinant and/or predictor of muscle condition than ASMI. Thus, we compared it to the ASMI determined by the BIA.
Patients and Methods
Our study included 165 ambulatory older adults (84 males, 81 females, mean age: 76.82 years). The ASMI by the BIA method, MT by US, and the distribution of body mass index (BMI) and body fat percentage (BFP) were examined using defined values for men and women. These were used as the basis for examining the association of MT and ASMI with handgrip strength (HGS), leg muscle strength (LMS), gait speed (GS), and echo intensity (EI). We compared HGS, LMS, GS, and EI for high and low ASMI among lower BMI or BFP. The same was also done for MT assessed by US.
Results
MT, as well as ASMI, was strongly associated with HGS and LMS. There was a correlation between MT and GS and EI but not between ASMI and GS and EI. There were significant differences in the prevalence between high ASMI and high MT or low ASMI and low MT in those with lower BMI or BFP. In non-overweight participants, HGS, LMS, GS, and EI were significantly higher in those with high MT than in those with low MT; however, there were no significant differences in them between those with high and low ASMI.
Conclusion
In the non-overweight group, the MT assessment by US showed a stronger relationship to muscle strength and muscle quality than the ASMI assessment by BIA. The MT assessment using US is a useful alternative to BIA-assessed ASMI, especially in non-overweight participants.
... [46][47][48] EMG samples the electrical properties of a few motor units whereas MUS affords a holistic view of residual disease burden, yielding information about muscle mass, tissue quality, fasciculations, and the overall distribution of pathological changes. [48][49][50][51][52] In 2M and 2D cohorts, we found SMA-related changes in nearly all major proximal, distal, and axial muscle groups of both the upper and lower body. Because 91% of baseline ultrasounds were normal among babies with two SMN2 copies, these early studies could not be used to predict later motor outcomes or muscle changes. ...
Objective
Compare efficacy of gene therapy alone (monotherapy) or in combination with an SMN2 augmentation agent (dual therapy) for treatment of children at risk for spinal muscular atrophy type 1.
Methods
Eighteen newborns with biallelic SMN1 deletions and two SMN2 copies were treated preemptively with monotherapy (n = 11) or dual therapy (n = 7) and followed for a median of 3 years. Primary outcomes were independent sitting and walking. Biomarkers were serial muscle ultrasonography (efficacy) and sensory action potentials (safety).
Results
Gene therapy was administered by 7–43 postnatal days; dual therapy with risdiplam (n = 6) or nusinersen (n = 1) was started by 15–39 days. Among 18 children enrolled, 17 sat, 15 walked, and 44% had motor delay (i.e., delay or failure to achieve prespecified milestones). Those on dual therapy sat but did not walk at an earlier age. 91% of muscle ultrasounds conducted within 60 postnatal days were normal but by 3–61 months, 94% showed echogenicity and/or fasciculation of at least one muscle group; these changes were indistinguishable between monotherapy and dual therapy cohorts. Five children with three SMN2 copies were treated with monotherapy in parallel: all sat and walked on time and had normal muscle sonograms at all time points. No child on dual therapy experienced treatment‐associated adverse events. All 11 participants who completed sensory testing (including six on dual therapy) had intact sural sensory responses.
Interpretation
Preemptive dual therapy is well tolerated and may provide modest benefit for children at risk for severe spinal muscular atrophy but does not prevent widespread degenerative changes.
... However, the ability of parameters defined from muscle ultrasound to predict meaningful outcomes is equivocal. 13,14 Limited predictive validity may partially be explained by sonographers using a subjective scale at the bedside (ie. the Heckmatt approach for qualitative evaluation of EI) 15 or the need for a trained expert to manually analyze ultrasound images for objective parameters. [16][17][18] The objective analysis of muscle parameters from ultrasound images is manual operator-dependent, requiring sustained human engagement that is time and labor-intensive, increasing the potential for human biases. ...
Introduction/Aims: Muscle ultrasound has high utility in clinical practice and research; however, the main challenges are the training and time required for manual analysis to achieve objective quantification of morphometry. This study aimed to develop and validate a software tool powered by artificial intelligence (AI) by measuring its consistency and predictability of expert manual analysis quantifying lower limb muscle ultrasound images across healthy, acute, and chronic illness subjects.
Methods: Quadriceps complex (QC [rectus femoris and vastus intermedius]) and tibialis anterior (TA) muscle ultrasound images of healthy, intensive care unit, and/or lung cancer subjects were captured with portable devices. Automated analyses of muscle morphometry were performed using a custom–built deep–learning model (MyoVision–US), while manual analyses were performed by experts.
Consistency between manual and automated analyses was determined using intraclass correlation
coefficients (ICC), while predictability of MyoVision–US was calculated using adjusted linear
regression (adj.R2).
Results: Manual analysis took approximately 24 hours to analyze all 180 images, while MyoVision–US took 247 seconds, saving roughly 99.8%. Consistency between the manual and automated analyses by ICC was good to excellent for all QC (ICC:0.85–0.99) and TA (ICC:0.93–0.99) measurements, even for critically ill (ICC:0.91–0.98) and lung cancer (ICC:0.85–0.99) images. The predictability of MyoVision−US was moderate to strong for QC (adj.R2:0.56–0.94) and TA parameters (adj.R2:0.81–0.97).
Discussion: The application of AI automating lower limb muscle ultrasound analyses showed
excellent consistency and strong predictability compared with human analysis. Future work needs to
explore AI–powered models for the evaluation of other skeletal muscle groups.
... Total echogenicity grade was calculated as the sum of the tested eight muscles grades. The patient was considered to have abnormal U/S when at least two of the tested muscles in upper or lower limb muscles had ultrasonic echogenicity of grades (II-IV) according to the scale of Heckmatt and colleagues [12] Data were analyzed using SPSS (statistical package for the social science software) Version 25.0. Quantitative variables were expressed by mean and standard deviation or by median and interquartile range (IQR) (as appropriate). ...
Background
Critical illness myopathy (CIM) has negative impact on patient outcomes. We aimed to explore the diagnostic value of bedside ultrasonography for early identification of CIM in septic patients and its correlation with other diagnostic methods. This prospective observational study included 40 ICU patients diagnosed with sepsis on admission or within 48 h later according to the third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3). They were evaluated using muscle ultrasound, electrodiagnostic and clinical muscle assessment (Medical Research Council, MRC) at two time points, the first was between days 2 and 5 and the second was between days 10 and 15.
Results
There was significant deterioration of neuromuscular function between the two evaluation points demonstrated by decline in MRC, abnormal nerve conduction and electromyography (EMG) and increased muscle echogenicity on ultrasonography ( P ≤ 0.001). Sepsis-Related Organ Failure Assessment (SOFA) score significantly correlated with different neuromuscular assessment tools. MRC had significant correlation with myopathic EMG ( P ≤ 0.001, r = − 0.869) and increased muscle echogenicity ( P ≤ 0.001, r = − 0.715). Abnormal ultrasonographic muscle architecture had sensitivity of 100%, specificity of 75% and positive likelihood ratio of 4 in detecting muscle dysfunction compared to myopathic EMG.
Conclusions
Bedside peripheral muscle ultrasound echogenicity grade could be used as an additional screening test in ICU septic patients for early detection of CIM.
... However, they provide limited insights on the mechanisms involved in performing the motion [e.g., 4,54,156,266]. Imaging techniques, for example, magnetic resonance imaging or ultrasound, allow the study of the morphology of muscles but can only incompletely assess the quality of the tissue [e.g., 102,146,173,209]. Electromyography (EMG), i.e., recorded via needle electrodes or non-invasively from the skin, contains information on the neural drive to the muscle as well as the state of the muscle itself [e.g., 45,175]. ...
Skeletal muscles generate bioelectromagnetic fields that contain information about the neural control of motions and the function of the muscle. One distinguishes between electromyography (EMG), the measurement of the muscle-induced electric potential field, and magnetomyography (MMG), the recording of muscle-induced magnetic fields. EMG is a well-established methodology, and its limitations have been extensively discussed in the scientific literature. In contrast, MMG is an emerging methodology with the potential to overcome some of the inherent limitations of EMG. To unlock the full potential of MMG, it is essential to support empirical observations from experiments with a solid theoretical understanding of muscle-induced bioelectromagnetic fields. Therefore, this thesis derives a novel multiscale skeletal muscle model that can predict realistic EMG and MMG signals. This model is used to conduct the first systematic comparison between surface EMG and non-invasive MMG. By using simulations, all system parameters can be controlled precisely. This would not be possible experimentally. The fundamental properties of EMG and MMG are systematically explored using simulations comparable to electrically or reflex-evoked contractions. Notably, it is shown that non-invasive MMG data is spatially more selective than comparable high-density EMG data. This property, for example, is advantageous for decomposing signals of voluntary contractions into individual motor unit spike trains. Using a novel in silico trial framework, it is demonstrated that non-invasive MMG-based motor unit decomposition is superior to the well-established surface EMG-based motor unit decomposition.
... Quantified echogenicity scores, measured using grayscale can then be measured across ultrasound images. Histogram-matching may therefore help overcome existing shortcomings of conventional QMUS 20,21 . Evaluation of the periscapular muscles which are linked to upper-limb function using this method may be used to inform clinical decisionmaking regarding subgrouping, evaluation of treatments, prognosis planning and surveillance. ...
Background and Objectives: Facioscapulohumeral dystrophy (FSHD) is a neuromuscular disease causing changes in muscle structure that can negatively affect upper-limb function. Echogenicity, measured using quantified muscle ultrasound, is a potential biomarker that could be used for informing decision making. Histogram-matching allows for image normalisation, which could enable comparison of echogenicity between different machine capture settings which is a current limitation. This study aimed to investigate if ultrasonography and histogram-matching can measure trapezius muscle echogenicity and morphology for differentiating between people with and without FSHD, and different levels of arm function.
Methods: Single measurement timepoint case control study of adults with FSHD and age- and sex- matched controls. Main outcomes were trapezius echogenicity and muscle thickness measured using 2D-ultrasound, and maximum thoracohumeral elevation angle, measured using 3D-movement analysis. A sensitivity analysis evaluating the effect of histogram-matching and different reference images was conducted. Between group differences for echogenicity were evaluated using an unpaired student t-test. Echogenicity, muscle thickness and range of movement were plotted to evaluate the explained variance between variables.
Results: Data was collected for 14 participants (10M:4F), seven with FSHD and seven controls with a mean (SD) age of 41.6 (15.7). Normalisation was necessary and echogenicity values for the FSHD group were higher than the controls (118.2 (34.0) vs 42.3 (14.0) respectively, with statistically significant differences (p=0.002). An overall variance of 6.2 (LLOA -2.9 to ULOA 15.4) was identified between reference images. Echogenicity accounted for the largest explained variance in muscle thickness (R2=0.81) and range of movement (R2=0.74), whilst muscle thickness and range of movement was the lowest (R2=0.61).
Discussion: People with FSHD demonstrated higher echogenicity, smaller muscle thicknesses and less range of movement. Histogram-matching for comparison of echogenicity values is necessary and can provide quantifiable differences. Different reference images affect echogenicity values but the variability is less than between group differences. Further work is needed to evaluate the longitudinal variability associated with this method on a larger sample of people with varying levels of arm function. Ultrasound scanning and post-histogram matching may be used to quantify and compare differences in muscle structure and function people with and without FSHD.
... The functional assessment of rectus femoris can involve dynamic ultrasound imaging during muscle contraction [90]. For example, the quadriceps can be assessed for its ability to contract and generate force during a leg lift. ...
Muscle wasting begins as soon as in the first week of one’s ICU stay and patients with multi-organ failure lose more muscle mass and suffer worse functional impairment as a consequence. Muscle wasting and weakness are mainly characterized by a generalized, bilateral lower limb weakness. However, the impairment of the respiratory and/or oropharyngeal muscles can also be observed with important consequences for one’s ability to swallow and cough. Muscle wasting represents the result of the disequilibrium between breakdown and synthesis, with increased protein degradation relative to protein synthesis. It is worth noting that the resulting functional disability can last up to 5 years after discharge, and it has been estimated that up to 50% of patients are not able to return to work during the first year after ICU discharge. In recent years, ultrasound has played an increasing role in the evaluation of muscle. Indeed, ultrasound allows an objective evaluation of the cross-sectional area, the thickness of the muscle, and the echogenicity of the muscle. Furthermore, ultrasound can also estimate the thickening fraction of muscle. The objective of this review is to analyze the current understanding of the pathophysiology of acute skeletal muscle wasting and to describe the ultrasonographic features of normal muscle and muscle weakness.
... sonographic evaluation was performed using a linear transducer. the frequency is at (4-13 Mhz) by saMsUNG MeDisON (UGeO h 60) on the affected spastic calf muscles to qualify muscle echo intensity using the heckmatt scale: grade i, normal; grade ii, an increase in muscle echo intensity with bone echo still distinct; grade iii, a marked increase in muscle echo intensity and a reduced bone echo; grade iV, a very high muscle echo intensity and complete loss of bone echo [22]. ...
Purpose:
To evaluate the effectiveness of radial extracorporeal shock wave therapy (r ESWT) as an additional treatment modality for spastic equinus deformity in chronic hemiplegic patients.
Methods:
100 eligible stroke patients with calf muscles spasticity were randomized into 2 groups. Group I: 50 patients exposed to rESWT 1.500 pulses, 0.10 mJ to 0.3mJ/mm2, with a frequency 4 Hz once weekly for one month. Group II: 50 patients exposed to Sham rESWT once weekly for one month. Clinical, electrophysiological & musculoskeletal ultrasound assessments were done for all patients.
Results:
After controlling baseline as covariate, the trend for modified Ashworth scale (MAS), Passive ankle dorsiflexion motion (PADFM), 10 meters walk test (10-MWT), and Ratio of maximum H reflex to maximum M response (H/M ratio) after one & two months was significantly different between the two groups, with improvement of all clinical and electrophysiological parameters in group I.
Conclusion:
ESWT represents a useful non-invasive, additional modality for the reduction of foot spasticity and equinus deformity in stroke patients.
... A semi-quantitative grading of echogenicity was assigned to each muscle group using the widely used Heckmatt visual grading score. Depending on the visual representation of the number of echoes displayed in the greyscale image using cortical bone as the visual anchor, a 1-4 grade is given, with one being normal and four markedly hyperechoic (12). ...
... It is classified as follows: 1-normal, 2-mildly increased muscle echoes with normal bone reflection, 3-moderately increased muscle echoes with reduced bone reflection and 4severely increased muscle echoes with absent bone reflection. 11 These techniques could also help to make an earlier diagnosis for this treatable myopathy. Pompe disease has a unique involvement of paraspinal and abdominal muscles and tongue 1 2 6 while inflammatory myopathies usually show significant oedema in proximal muscles on MRI or increased fascial thickness on ultrasound scanning. ...
Late-onset Pompe disease manifests predominantly in the proximal lower limbs and may be mistaken for an inflammatory myopathy. A 46-year-old man with acromegaly had an 8-year history of progressive weakness. His myopathy was initially attributed to the acromegaly, but severe progression prompted a muscle biopsy, which suggested an inflammatory myopathy. However, his weakness progressed despite treatment for polymyositis. His muscle ultrasound scan pattern was more suggestive of Pompe disease than polymyositis, and Pompe disease was confirmed by genetic and enzymatic testing. Patients with apparent polymyositis, which persists despite treatment, require reconsideration of the diagnosis, with particular attention to treatable genetic causes.
... We also documented muscle intensity using the fourpoint-Heckmatt scale [18]. To better understand pain related to the presented disorders, we also collected data using the Numeric Rating Scale (NRS) [19]. ...
Neuromuscular disorders show extremely varied expressions of different symptoms and the involvement of muscles. Non-invasively, myotonia and muscle stiffness are challenging to measure objectively. Our study aims to test myotonia, elasticity, and stiffness in various neuromuscular diseases and to provide reference values for different neuromuscular disease groups using a novel handheld non-invasive myometer device MyotonPRO®. We conducted a monocentric blinded cross-sectional study in patients with a set of distinct neuromuscular diseases (NCT04411732, date of registration June 2, 2020). Fifty-two patients in five groups and 21 healthy subjects were enrolled. We evaluated motor function (6-min walk test, handheld dynamometry, Medical Research Council (MRC) Scale) and used ultrasound imaging to assess muscle tissue (Heckmatt scale). We measured muscle stiffness, frequency, decrement, creep, or relaxation using myotonometry with the device MyotonPRO®. Statistically, all values were calculated using the t test and Mann–Whitney U test. No differences were found in comparing the results of myotonometry between healthy and diseased probands. Furthermore, we did not find significant results in all five disease groups regarding myotonometry correlating with muscle strength or ultrasound imaging results. In summary, the myometer MyotonPRO® could not identify significant differences between healthy individuals and neuromuscular patients in our patient collective. Additionally, this device could not distinguish between the five different groups of disorders displaying increased stiffness or decreased muscle tone due to muscle atrophy. In contrast, classic standard muscle tests could clearly decipher healthy controls and neuromuscular patients.
... Zur Quantifizierung der ME können zwei Verfahren angewendet werden: zum einen die softwarebasierte Graustufenanalyse [46] und zum anderen die visuelle Beurteilung anhand der vierstufigen Heckmatt-Skala (. Abb. 4, [25]). ...
Intensive care unit-acquired weakness (ICUAW) is one of the most common neuromuscular complications in intensive care medicine. The clinical diagnosis and assessment of the severity using established diagnostic methods (e.g., clinical examination using the Medical Research Council Sum Score or electrophysiological examination) can be difficult or even impossible, especially in sedated, ventilated and delirious patients. Neuromuscular ultrasound (NMUS) has increasingly been investigated in ICUAW as an easy to use noninvasive and mostly patient compliance-independent diagnostic alternative. It has been shown that NMUS appears to be a promising tool to detect ICUAW, to assess the severity of muscular weakness and to monitor the clinical progression. Further studies are needed to standardize the methodology, to evaluate the training effort and to optimize outcome predication. The formulation of an interdisciplinary neurological and anesthesiological training curriculum is warranted to establish NMUS as a complementary diagnostic method of ICUAW in daily clinical practice.
... Heckmatt et al. in 1980, for the first time, described these observations and subsequently proposed a grading system known as "Heckmatt criteria" having four different grades: grade 1: normal echogenicity, Grade 2: muscle echo increased and bone still distinct; Grade 3: markedly increased muscle echo and bone echogenicity reduced, and Grade 4: very strong muscle echo with and complete loss of bone echogenicity. [10] However, since US is operator-dependent, several factors can influence the assessment. Patient position, machine settings, and the plane of view can affect the echogenicity of the muscle. ...
... Body fat, evaluated using bioimpedance, and echo intensity of muscle, evaluated by ultrasound imaging, were also not changed in either group (Table 2). Echo intensity is related to the amount of intramuscular fat and fibrous tissue [49,50], but these noncontractile components were not changed after such low-intensity training in the present study. It may be necessary to improve muscle quality and decrease body fat with more high-intensity training [51] and long-term aerobic exercise. ...
Background
It is important to investigate neural as well as muscle morphological adaptations to evaluate the effects of exercise training on older adults.
Aims
This study was aimed to investigate the effects of home-based bodyweight squat training on neuromuscular adaptation in older adults.
Methods
Twenty-five community-dwelling older adults (77.7 ± 5.0 years) were assigned to squat (SQU) or control (CON) groups. Those in the SQU group performed 100 bodyweight squats every day and the others in the CON group only performed daily activities for 4 months. Maximum knee extension torque and high-density surface electromyography during submaximal contraction were assessed. Individual motor units (MUs) were identified and divided into relatively low or high-recruitment threshold MU groups. Firing rates of each MU group were calculated. The muscle thickness and echo intensity of the lateral thigh were assessed using ultrasound. As physical tests, usual gait speed, timed up and go test, grip strength, and five-time chair stand test were performed.
Results
While no improvements in muscle strength, muscle thickness, echo intensity, or physical tests were noted in either group, the firing rate of relatively low recruitment threshold MUs significantly decreased in the SQU group after intervention.
Conclusions
These results suggest that low-intensity home-based squat training could not improve markedly muscle strength or physical functions even if high-repetition and high frequency exercise, but could modulate slightly neural activation in community-dwelling older adults.
... A significant correlation was observed between the semiquantitative scale and VAS echogenicity. Both these visual scales grade muscle echogenicity abnormalities based on extent of muscle involved as opposed to degree of echo-intensity changes, as is the custom for grading US muscle echogenicity in myopathies/neuromuscular disorders (32). While a multifocal increase of muscle echogenicity could be observed in several neuromuscular disorders, such as muscular dystrophies, motor neuron disease ("moth-eaten appearance") and inflammatory myositis, a homogeneous and broad involvement of muscle structures would be expected in patients with sarcopenia. ...
Objectives
To investigate the inter/intra-reliability of ultrasound (US) muscle echogenicity in patients with rheumatic diseases.
Methods
Forty-two rheumatologists and 2 radiologists from 13 countries were asked to assess US muscle echogenicity of quadriceps muscle in 80 static images and 20 clips from 64 patients with different rheumatic diseases and 8 healthy subjects. Two visual scales were evaluated, a visual semi-quantitative scale (0–3) and a continuous quantitative measurement (“VAS echogenicity,” 0–100). The same assessment was repeated to calculate intra-observer reliability. US muscle echogenicity was also calculated by an independent research assistant using a software for the analysis of scientific images (ImageJ). Inter and intra reliabilities were assessed by means of prevalence-adjusted bias-adjusted Kappa (PABAK), intraclass correlation coefficient (ICC) and correlations through Kendall’s Tau and Pearson’s Rho coefficients.
Results
The semi-quantitative scale showed a moderate inter-reliability [PABAK = 0.58 (0.57–0.59)] and a substantial intra-reliability [PABAK = 0.71 (0.68–0.73)]. The lowest inter and intra-reliability results were obtained for the intermediate grades (i.e., grade 1 and 2) of the semi-quantitative scale. “VAS echogenicity” showed a high reliability both in the inter-observer [ICC = 0.80 (0.75–0.85)] and intra-observer [ICC = 0.88 (0.88–0.89)] evaluations. A substantial association was found between the participants assessment of the semi-quantitative scale and “VAS echogenicity” [ICC = 0.52 (0.50–0.54)]. The correlation between these two visual scales and ImageJ analysis was high (tau = 0.76 and rho = 0.89, respectively).
Conclusion
The results of this large, multicenter study highlighted the overall good inter and intra-reliability of the US assessment of muscle echogenicity in patients with different rheumatic diseases.
Muscle ultrasound is a valuable non-invasive and cost-effective method in assessing muscle mass and structure, both of which are significant indicators for the development of sarcopenia and frailty in elderly individuals. Sarcopenia refers to the loss of muscle mass and strength that occurs with age, whereas frailty is a complex geriatric syndrome characterized by reduced physical function and an increased susceptibility to negative health outcomes. Both conditions are prevalent in older adults and are associated with higher risks of falls, disability, and mortality. By measuring muscle size and structure and several other ultrasound parameters, including muscle thickness, cross-sectional area, echogenicity (brightness in the ultrasound image), pennation angle, and fascicle length ultrasound can assist in identifying sarcopenia and frailty in older adults. In addition, ultrasound can be used to evaluate muscle function such as muscle contraction and stiffness, which may also be affected in sarcopenia and frailty. Therefore, muscle ultrasound could lead to better identification and tracking of sarcopenia and frailty. Such advancements could result in the implementation of earlier interventions to prevent or treat these conditions, resulting in an overall improvement in the health and quality of life of the elderly population. This narrative review describes the benefits and challenges when using ultra-sound for the evaluation of frailty and sarcopenia.
Botulinum Neurotoxin Type A (BoNT-A) injections using Ultrasound (US) guidance have led to research evaluating changes in muscle architecture. Controversy remains as to what constitutes increased Echo-Intensity (EI) in spastic muscles and whether this may affect outcomes. We aim to provide a narrative review of US muscle architecture changes following Central Nervous System (CNS) lesions and explore their relationship to spasticity. Medline, CINAHL, and Embase databases were searched with keywords: ultrasonography, hypertonia, spasticity, fibrosis, and Heckmatt. Three physicians reviewed the results of the search to select relevant papers. Reviews identified in the search were used as a resource to identify additional studies. A total of 68 papers were included. Four themes were identified, including histopathological changes in spastic muscle, effects of BoNT-A on the muscle structure, available US modalities to assess the muscle, and utility of US assessment in clinical spasticity. Histopathological studies revealed atrophic and fibro-fatty changes after CNS lesions. Several papers described BoNT-A injections contributing to those modifications. These changes translated to increased EI. The exact significance of increased muscle EI remains unclear. The Modified Heckmatt Scale (MHS) is a validated tool for grading muscle EI in spasticity. The use of the US may be an important tool to assess muscle architecture changes in spasticity and improve spasticity management. Treatment algorithms may be developed based on the degree of EI. Further research is needed to determine the incidence and impact of these EI changes in spastic muscles.
Introduction/Aims
Muscle strength, functional status, and muscle enzymes are conventionally used to evaluate disease status in idiopathic inflammatory myopathies (IIM). This study aims to investigate the role of quantitative muscle ultrasound in evaluating disease status in IIM patients.
Methods
Patients with IIM, excluding inclusion body myositis, were recruited along with age‐ and sex‐matched healthy controls (HC). All participants underwent muscle ultrasound and clinical assessments. Six limb muscles were unilaterally scanned using a standardized protocol, measuring muscle thickness (MT) and echo intensity (EI). Results were compared with HC, and correlations were made with outcome measures.
Results
Twenty IIM patients and 24 HC were recruited. The subtypes of IIM were dermatomyositis (6), necrotizing myositis (6), polymyositis (3), antisynthetase syndrome (3), and nonspecific myositis (2). Mean disease duration was 8.7 ± 6.9 years. There were no significant differences in demographics and anthropometrics between patients and controls. MT of rectus femoris in IIM patients was significantly lower than HC. Muscle EI of biceps brachii and vastus medialis in IIM patients were higher than HC. There were moderate correlations between MT of rectus femoris and modified Rankin Scale, Physician Global Activity Assessment, and Health Assessment Questionnaire, as well as between EI of biceps brachii and Manual Muscle Testing‐8.
Discussion
Muscle ultrasound can detect proximal muscle atrophy and hyperechogenicity in patients with IIM. The findings correlate with clinical outcome measures, making it a potential tool for evaluating disease activity of patients with IIM in the late phase of the disease.
Introduction/Aims
Muscle ultrasound has been investigated in children with spinal muscular atrophy (SMA) and proposed as a potential biomarker of disease severity. We studied the ultrasound properties in adults with SMA to see whether they also have potential as markers of disease severity in older patients.
Methods
Thickness and quantitative echogenicity of muscle and subcutaneous tissue were compared between eight prospectively recruited adult patients with SMA and eight age, sex and body mass index‐matched controls. Measurements were made in the dominant deltoid, biceps, triceps, forearm extensors, first dorsal interosseous, quadriceps, tibialis anterior, and gastrocnemius muscles. The muscle‐to‐subcutaneous (M:S) thickness and echogenicity ratios were also calculated. A mean value across all muscles as well as the individual values for each muscle were then calculated for each parameter in each subject and compared between the two groups. Significance was set at 0.05 after Bonferroni correction.
Results
In the SMA patients, mean muscle thickness was significantly smaller (1.3 vs. 1.9 cm), muscle echogenicity higher (106 vs. 67 on the grayscale level), and subcutaneous thickness larger (0.9 vs. 0.3 cm) than in controls; M:S echogenicity ratio was significantly increased and M:S thickness ratio reduced in the patients. The most abnormal scores were found in the nonambulatory patients and the least abnormal in the ambulatory patients.
Discussion
Ultrasound can detect and quantify the severity of muscle atrophy and structure in adult SMA, suggesting a potential role as a marker of disease severity, which will require validation by larger studies.
Pompe disease (PD) is a rare autosomal-recessive glycogen storage disorder resulting in proximal muscle weakness and loss of respiratory function. While enzyme replacement therapy (ERT) is the only effective treatment, biomarkers for disease monitoring are scarce. After ex vivo biomarker validation in phantom studies, we applied multispectral optoacoustic tomography (MSOT), a molecular sensitive ultrasound approach, in a clinical trial (NCT05083806) to image biceps muscles of 10 late-onset PD patients (LOPD) compared to matched healthy controls. MSOT was compared to muscle magnetic resonance imaging (MRI), ultrasound, spirometry, muscle testing, and quality of life score (QOL). Additionally, the results were validated in an independent LOPD patient cohort from a second clinical site. Our study demonstrated that MSOT enabled imaging of subcellular disease pathology with increases in glycogen/water, collagen and lipid signals providing higher sensitivity to detect muscle degeneration than current clinical and imaging methods. This translation approach suggests implementation in the complex care of these ultra-rare disease patients.
Introduction/Aims
Needle electromyography (EMG) and muscle ultrasound can be used to evaluate patients with suspected neuromuscular disorders. The relation between muscle ultrasound pathology and the corresponding needle EMG findings is unknown. In this study we compared the results of concurrent ultrasound and needle EMG examinations in patients suspected of a neuromuscular disorder.
Methods
Retrospective data from 218 patients with pairwise ultrasound and EMG results of 796 muscles were analyzed. We compared overall quantitative and visual muscle ultrasound results to EMGs with neurogenic and myopathic abnormalities and assessed the congruency of both methods in the different clinical diagnosis categories.
Results
In muscles of patients with a neuromuscular disorder, abnormalities were found with EMG in 71.8%, and quantitative and visual muscle ultrasound results were abnormal in 19.3% and 35.4% respectively. In muscles with neurogenic EMG abnormalities, quantitative and visual muscle ultrasound results were abnormal in 18.9% versus 35.6%, increasing up to 43.7% versus 87.5% in muscles with the most pronounced signs of denervation. Congruency of EMG and ultrasound was better for more proximal and cranial muscles than for muscles in the hand and lower limb.
Discussion
Needle EMG and muscle ultrasound produce disparate results more often than not and identify different aspect of muscle pathology. Muscle ultrasound seems less suited for detecting mild neurogenic abnormalities. As the severity of neurogenic needle EMG abnormalities increased, muscle ultrasound abnormalities were also increasingly found. For detecting neurogenic abnormalities, visual analysis seems better suited than grayscale quantification.
Ultrasound (US) imaging has seen major advancements over the last few decades, with this imaging modality becoming routinely used during the initial clinical assessment. The use of US as a medical imaging device can be traced back to 1942 and has been in use since. The cost, ease of access, and pain-free applications associated with US imaging, makes this imaging modality preferred by patients. US skills coupled with anatomical knowledge make clinical diagnosis using US more accurate in patient care.
US is used in both inflammatory and noninflammatory diseases. Rheumatologists have advanced the treatment of various forms of arthritis and have employed US as a means of assessing the type of arthritis present and determining the appropriate treatment plan. Medical examinations using US are advantageous to patient education and provide the rationale for the treatment choice. The advancement of US imaging has improved extensively and is in some settings documented as being as effective as MRI and CT imaging. US imaging in the treatment of musculoskeletal diseases has seen many improvements, with some applications noted in the assessment of pressure ulcers in patients presenting with a spinal cord injury. US is used to evaluate the tissue found superficial to the ischial tuberosity and is used to document tissue properties that make patients susceptible to the development of pressure ulcers.
This chapter outlines the history of US imaging and its role in the treatment of various musculoskeletal diseases such as arthritis. Probe selection plays an important role in diagnosis as it allows for the optimization of an image and as such disease monitoring. The role of US in the investigation of tissue composition below the ischial tuberosity and its role in the evaluation of pressure ulcers will be covered in this chapter, as well as the future direction of US imaging. Fusion imaging, 3D imaging and contrast-enhanced US are some of the recent advances made in rheumatology, which seek to combine and overcome the limitations associated with MRI and CT imaging. The high learning curve associated with US imaging when weighed against its benefits, makes point of care ultrasound (POCUS) ideal for the clinical setting.
Purpose of review:
Imaging techniques such as MRI, ultrasound and PET/computed tomography (CT) have roles in the detection, diagnosis and management of myositis or idiopathic inflammatory myopathy (IIM). Imaging research has also provided valuable knowledge in the understanding of the pathology of IIM. This review explores the latest advancements of these imaging modalities in IIM.
Recent findings:
Recent advancements in imaging of IIM have seen a shift away from manual and qualitative analysis of the images. Quantitative MRI provides more objective, and potentially more sensitive characterization of fat infiltration and inflammation in muscles. In addition to B-mode ultrasound changes, shearwave elastography offers a new dimension to investigating IIM. PET/CT has the added advantage of including IIM-associated findings such as malignancies.
Summary:
It is evident that MRI, ultrasound and PET/CT have important roles in myositis. Continued technological advancement and a quest for more sophisticated applications help drive innovation; this has especially been so of machine learning/deep learning using artificial intelligence and the developing promise of texture analysis.
Objective:
FHL1-related reducing body myopathy is an ultra-rare, X-linked dominant myopathy. In this cross-sectional study, we characterize skeletal muscle ultrasound, muscle MRI, and cardiac MRI findings in FHL1-related reducing body myopathy patients.
Methods:
Seventeen patients (11 male, mean age 35.4, range 12-76 years) from nine independent families with FHL1-related reducing body myopathy underwent clinical evaluation, muscle ultrasound (n = 11/17), and lower extremity muscle MRI (n = 14/17), including Dixon MRI (n = 6/17). Muscle ultrasound echogenicity was graded using a modified Heckmatt scale. T1 and STIR axial images of the lower extremity muscles were evaluated for pattern and distribution of abnormalities. Quantitative analysis of intramuscular fat fraction was performed using the Dixon MRI images. Cardiac studies included electrocardiogram (n = 15/17), echocardiogram (n = 17/17), and cardiac MRI (n = 6/17). Cardiac muscle function, T1 maps, T2-weighted black blood images, and late gadolinium enhancement patterns were analyzed.
Results:
Muscle ultrasound showed a distinct pattern of increased echointensity in skeletal muscles with a nonuniform, multifocal, and "geographical" distribution, selectively involving the deeper fascicles of muscles such as biceps and tibialis anterior. Lower extremity muscle MRI showed relative sparing of gluteus maximus, rectus femoris, gracilis, and lateral gastrocnemius muscles and an asymmetric and multifocal, "geographical" pattern of T1 hyperintensity within affected muscles. Cardiac studies revealed mild and nonspecific abnormalities on electrocardiogram and echocardiogram with unremarkable cardiac MRI studies.
Interpretation:
Skeletal muscle ultrasound and muscle MRI reflect the multifocal aggregate formation in muscle in FHL1-related reducing body myopathy and are practical and informative tools that can aid in diagnosis and monitoring of disease progression.
Peripheral neuroregenerative research and therapeutic options are expanding exponentially. With this expansion comes an increasing need to reliably evaluate and quantify nerve health. Valid and responsive measures of the nerve status are essential for both clinical and research purposes for diagnosis, longitudinal follow-up, and monitoring the impact of any intervention. Furthermore, novel biomarkers can elucidate regenerative mechanisms and open new avenues for research. Without such measures, clinical decision-making is impaired, and research becomes more costly, time-consuming, and sometimes infeasible. Part 1 of this two-part scoping review focused on neurophysiology. In Part 2, we identify and critically examine many current and emerging non-invasive imaging techniques that have the potential to evaluate peripheral nerve health, particularly from the perspective of regenerative therapies and research.
Introduction/aims:
Orofacial muscle ultrasound images can be evaluated quantitatively or using a visual grading system. Quantitative muscle ultrasound (QMUS) is currently the most sensitive technique to detect pathology, but can be time-consuming. The aim of this study was to investigate the validity and reliability of two visual grading systems (the original Heckmatt scale or a modified 3-point version) for the optimal grading of orofacial muscle images.
Methods:
A retrospective, comparative, reliability and validity study was performed. Ultrasound images of the digastric, geniohyoid, masseter, temporalis muscles, and intrinsic muscles of the tongue of healthy participants and of patients (suspected of) having a neuromuscular disease were included. QMUS was used as the "gold standard." Two expert raters and one inexperienced rater rated all ultrasound images using both visual grading systems.
Results:
A total of 511 ultrasound images were included. Criterion validity showed Spearman rho correlation coefficients of >0.59. Construct validity analysis showed strong to very strong associations between the visual grading systems and mastication and/or swallowing. Inter- and intrarater reliability of the original Heckmatt scale and the modified scale were good and comparable. Rater experience had a beneficial effect on the interrater reliability of both scales.
Discussion:
Both the original Heckmatt and the modified Heckmatt scale are valid and reliable tools for the visual grading of orofacial ultrasound images. The modified Heckmatt scale, with only three grades and including an "uncertain" category, is considered easier to use in clinical practice.
Objectives
We investigated shear wave elastography (SWE), B mode ultrasound (US) and power Doppler (PD) as imaging biomarkers for longitudinal follow-up in idiopathic inflammatory myopathy (IIM), with a particular focus on immune-mediated necrotising myopathy (IMNM) and dermatomyositis (DM).
Methods
Participants had serial SWE, US and PD on the deltoid (D) and vastus lateralis (VL) muscles on four occasions at intervals of 3-6 months. Clinical assessments included manual muscle testing, and patient and physician reported outcome scales.
Results
Thirty three participants were included: IMNM= 17, DM = 12, overlap myositis= 3, polymyositis =1. Twenty were in a prevalent clinic group, and 13 were recently treated cases in an incident group. Differential changes in SWS and US domains occurred with time in both the prevalent and incident groups. In VL-prevalent, echogenicity increased over time (p = 0.040), while in incident cases there was a trend of reduction to normal over time (p = 0.097) with treatment. Muscle bulk reduced in D-prevalent group (p = 0.096) over time, suggesting atrophy. SWS also reduced in the VL-incident (p = 0.096) group over time, suggesting a trend towards improvement in muscle stiffness with treatment.
Conclusion
SWE and US appear promising as imaging biomarkers for patient follow-up in IIM and indicate changes over time, especially with echogenicity, muscle bulk and SWS in the VL. Due to the limitations of participant numbers, additional studies with a larger cohort will help to evaluate these US domains further and outline specific characteristics within the IIM subgroups.
Neurologists in both the inpatient and outpatient settings are increasingly using ultrasound to diagnose and manage common neurological diseases. Advantages include cost-effectiveness, the lack of exposure to ionizing radiation, and the ability to perform at the bedside to provide real-time data. There is a growing body of literature that supports using ultrasonography to improve diagnostic accuracy and aid in performing procedures. Despite the increasing utilization of this imaging modality in medicine, there has been no comprehensive review of the clinical applications of ultrasound in the field of neurology. We discuss the current uses and limitations of ultrasound for various neurological conditions. We review the role for ultrasound in commonly performed neurologic procedures including lumbar puncture, botulinum toxin injections, nerve blocks, and trigger point injections. We specifically discuss the technique for ultrasound-assisted lumbar puncture and occipital nerve block as these are commonly performed. We then focus on the utility of ultrasound in the diagnosis of neurologic conditions. This includes neuromuscular diseases such as motor neuron disorders, focal neuropathies, and muscular dystrophy as well as vascular conditions such as stroke and vasospasm in subarachnoid hemorrhage. We also address ultrasound's use in critically ill patients to aid in identifying increased intracranial pressure, hemodynamics, and arterial and/or venous catheterization. Finally, we address the importance of standardized ultrasound curricula in trainee education and make recommendations for the future directions of research and competency guidelines within our specialty.
Neuromuscular disease includes a wide range of muscular disorders, but it lacks convenient and effective tools for clinical diagnosis and therapeutic monitoring. As a widely used imaging tool, ultrasound can clearly display muscle structure and create basic conditions for accurate image analysis. At present, many studies have tried to obtain information on muscle function and pathological changes by analyzing the features of muscle ultrasound images, and have shown reliable results. However, the minimal changes in muscle structure and image texture are easy to be neglected, and manual segmentation and data analysis are time-consuming tasks. Artificial intelligence (AI) can accurately identify image changes and improve the efficiency of image analysis, and the muscle ultrasonic image analysis model developed based on AI has shown advantages in a large number of research results. This review summarizes the relevant studies of muscle ultrasound imaging and AI in the field of it, including a variety of research based on traditional AI methods or deep learning methods, as well as discusses the clinical significance of ultrasound analysis assisted by AI and the future exploration directions in this field.
Objective:
We investigated ultrasound patterns of muscle involvement in different types of spinal muscular atrophy (SMA) and their correlation with functional status to determine the pattern of muscle compromise in patients with SMA and the potential role of ultrasound to evaluate disease progression.
Methods:
We examined muscles (biceps brachii, rectus femoris, diaphragm, intercostals and thoracic multifidus) of 41 patients with SMA (types 1 to 4) and 46 healthy age- and sex-matched control individuals using B-mode ultrasound for gray-scale analysis (GSA), area (biceps brachii and rectus femoris) and diaphragm thickening ratio. Functional scales were applied to patients only. We analyzed ultrasound abnormalities in specific clinical subtypes and correlated findings with functional status.
Results:
Compared with controls, patients had reduced muscle area and increased mean GSA for all muscles (p < 0.001), with an established correlation between the increase in GSA and the severity of SMA for biceps brachii, rectus femoris and intercostals (p = 0.03, 0.01 and 0.004 respectively) when using the Hammersmith Functional Motor Scale Expanded. Diaphragm thickening ratio was normal in the majority of patients, and intercostal muscles had higher GSA than diaphragm in relation to the controls.
Conclusion:
Ultrasound is useful for quantifying muscular changes in SMA and correlates with functional status. Diaphragm thickening ratio can be normal even with severe compromise of respiratory muscles in quantitative analysis, and intercostal muscles were more affected than diaphragm.
Objective: Quantify and categorize by sex, age, and time spent on mechanical ventilation (MV), the decline in skeletal muscle mass, strength and mobility in critically ill patients infected with SARS-CoV-2 and requiring mechanical ventilation while at intensive care unit (ICU).
Design: Prospective observational study including participants recruited between June 2020 and February 2021 at Hospital Clínico Herminda Martin (HCHM), Chillán, Chile. The thickness of the quadriceps muscle was evaluated by ultrasonography (US) at intensive care unit admission and awakening. Muscle strength and mobility were assessed, respectively, through the Medical Research Council Sum Score (MRC-SS) and the Functional Status Score for the Intensive Care Unit Scale (FSS-ICU) both at awakening and at ICU discharge. Results were categorized by sex (female or male), age (<60 years old or ≥60 years old) and time spent on MV (≤10 days or >10 days).
Setting: Intensive care unit in a public hospital.
Participants: 132 participants aged 18 years old or above (women n = 49, 60 ± 13 years; men n = 85, 59 ± 12 years) admitted to intensive care unit with a confirmed diagnosis of severe SARS-CoV-2 and requiring MV for more than 48 h were included in the study. Patients with previous physical and or cognitive disorders were excluded.
Interventions: Not applicable.
Results: Muscle thickness have significantly decreased during intensive care unit stay, vastus intermedius (−11%; p = 0.025), rectus femoris (−20%; p < 0.001) and total quadriceps (−16%; p < 0.001). Muscle strength and mobility were improved at intensive care unit discharge when compared with measurements at awakening in intensive care unit (time effect, p < 0.001). Patients ≥60 years old or on MV for >10 days presented greater muscle loss, alongside with lower muscle strength and mobility.
Conclusion: Critically ill patients infected with SARS-CoV-2 and requiring MV presented decreased muscle mass, strength, and mobility during their intensive care unit stay. Factors associated with muscle mass, such as age >60 years and >10 days of MV, exacerbated the critical condition and impaired recovery.
Purpose:
The purpose of this study was to compare the measurement of shear wave elastography (SWE) and gray scale ultrasonography (GSU) and CT attenuation of mid-rectus femoris (RF) muscle in healthy adults.
Methods:
This prospective study included 70 participants with a healthy body mass index (<25 kg/m2 ) between June 2019 and January 2020. Echo intensity (EI) grading of RF on GSU was performed. SWE was performed for the three levels of the RF. Measurements were repeated 10 min after the first measurement. The mid-RF attenuation on CT was also measured. Interobserver agreement of EI grade among three readers was assessed using weighted-kappa statistics. The reliability of SWE was assessed using intraclass correlation coefficient. The correlations between the SWE and CT/GSU measurements were analyzed.
Results:
Interobserver agreement of EI grade on GSU by the three radiologists was moderate to substantial (k = 0.562-0.767). The inter-session agreements for SWE were almost perfect for mid RF (k = 0.822-0.829) and substantial for proximal and distal RF (k = 0.767-0.795). There were significant correlations between SWE-EI and SWE-CT attenuation (p < 0.001, respectively) at the mid-RF.
Conclusions:
SWE measurements on mid-RF demonstrated the highest reliability. SWE parameters showed a strong correlation with EI on GSU and attenuation on CT.
Background and purpose:
Novel light- and sound-based technologies like multispectral optoacoustic tomography (MSOT) with co-registered reflected-ultrasound computed tomography (RUCT) could add additional value to conventional ultrasound (US) for disease phenotyping in pediatric spinal muscular atrophy (SMA). The aim of this study was to investigate the quality of RUCT compared to US for qualitative and quantitative assessment of imaging neuromuscular disorders.
Methods:
Subanalyzing the MSOT SMA study, 288 RUCT and 276 US images from 10 SMA patients (mean age 9.0 ± 3.7) and 10 gender- and age-matched healthy volunteers (HV; mean age 8.7 ± 4.3) were analyzed for quantitative (grayscale levels [GSLs]) and qualitative (echogenicity, distribution pattern, Heckmatt scale, and muscle texture) muscle changes. RUCT and US measures were further correlated with clinical standard motor outcomes.
Results:
Quantitative agreement using GSLs revealed significantly higher GSLs in muscles of SMA patients compared to healthy muscles in both techniques (US mean GSL [SD] SMA vs. HV: 110.70 [27.8] vs. 68.85 [19.2], p < .0001; RUCT mean GSL [SD] SMA vs. HV: 91.81 [21.8] vs. 59.86 [8.2], p < .0001) with good correlation with motor outcome tests, respectively. Qualitative agreement between methods for muscle composition was excellent for differentiation of pathological versus healthy muscles, echogenicity, and distribution pattern, moderate for Heckmatt scale, and poor for muscle texture.
Conclusions:
The data suggest that RUCT may allow the assessment of basic qualitative and quantitative measures for muscular diseases with comparable results to conventional US.
Cancer cachexia causes significant declines in skeletal muscle mass and strength and is associated with a poor prognosis and impaired activities of daily living and quality of life. Therefore, treating cachexia is an important aim in physical therapy in patients with cancer. Although many studies have reported that training exercises can reduce cancer-related declines in muscle mass and strength, there is still no consensus on the most effective exercise protocol. The first part of this paper reviews the effectiveness of various exercise protocols in animal models of cancer cachexia and in patients with advanced cancer. The review includes resistance training, aerobic training, and combined training performed at least twice per week at an intensity of at least 60% of the maximal strength or heart rate. Protocols that included resistance training appeared to yield the greatest improvements in muscle strength. However, improvements in muscle mass are rarely reported, and the methods used to measure muscle mass are inconsistent. Therefore, the latter half of this paper describes clinically relevant methods for assessing muscle mass and quality. To develop the field of cancer rehabilitation, further studies should examine in detail how physical activity affects muscle mass and muscle quality, in addition to muscle strength.
Isometric and dynamic strength and endurance of knee extensors were tested in 18 young males. The relative composition of slow (ST) and fast twitch (FT) fibers in the vastus lateralis muscle was registered from needle biopsies. Thigh muscle volume was evaluated from ultrasonic measurements. Six subjects served as controls, six trained with 50%, and six with 80% dynamic strength three times per week for 7 weeks with 20 and 12 repetitions per session, respectively. The training load was adjusted to the increases in strength observed during training. Dynamic strength increased by 42.3% in the 80% group (p< 0.01). In the control group and 50% group no significant increases were observed. Dynamic endurance: Controls showed no change. There was an over-all increase in the 50% group, while the 80% group only increased dynamic endurance for heavier loads. Isometric strength and endurance and fiber composition did not change in any group. In the 50% group the area of FT-realtive to ST-fibers increased 12.4% (p>0.05). Dynamic strength relative to muscle cross section increased by 30% in the 80% group (p<0.01) positively correlated to relative content of FT fibers.
The present results confirm the specificity of training and indicate that a high content of FT fibers is a prerequisite for a successful strength training.
Percutaneous needle biopsy of skeletal muscle can be used in the diagnosis of muscle disease. Because the technique is easy and readily repeated it offers a number of advantages over open biopsy, including the study of the course of a disease, the response to treatment, the early diagnosis of systemic disease, and the investigation of carriers. No complications followed needle biopsies in thirty-two patients with symptoms and signs of muscle disease, and the material obtained was adequate, both in quantity and state of preservation, for examination by light and electron microscopy.
Summary By means of the ultrasonic photography of the cross-section of the acting muscle bundle, together with the measurement of the muscle strength developed by the subject with maximum effort, the strength per unit area of the muscle was calculated in 245 healthy human subjects, including 119 male and 126 female.The result was summarized as the following:1.
The ultrasonic method used in this work was possibly admitted as the best way to calculate the cross-sectional area of the muscle.
2.
The arm strength was fairly proportional to the cross-sectional area of the flexor of the upper arm regardless of age and sex.
3.
The strength per unit cross-sectional area of flexor of the upper arm was 6.3 kg/cm2 in the average, standard deviation of 0.81 kg/cm2. When cross-sectional area of muscle was measured at extensive position of the forearm the strength per unit area was calculated to be 4.7 kg/cm2 at flexed position of the forearm.
4.
As to the individual variation, the strength per unit area was distributed in a range from 4 kg/cm2 to 8 kg/cm2.
5.
The strength per unit cross-sectional area was almost the same in male and female regardless of age. In addition to that, there was not found any significant difference in ordinary and trained adult.
A comparative study of the ultrasound appearances of the thigh with the static B scan showed consistent differences in 10 children with muscular dystrophy compared with 40 healthy controls. This non-invasive technique could be useful in assessing the extent of pathological change in dystrophic patients and could prove a valuable diagnostic aid.
The author presents a detailed analysis of recent studies on the muscular performance of subjects afflicted with muscular dystrophy. It is emphasised that doing an exercise represents an integrated activity which is not directly relatable to the force of contraction. The progress of the disease can be established by making serial measurements of muscle force which gradually falls as body weight falls. In subjects with muscular dystrophy, a reduced maximum force per cross-sectional area of chemically skinned fibers has been reported. New techniques are available to examine whether or not muscle bulk has been replaced by fat or connective tissue. Increased myofibrillar breakdown has been found in patients with Duchenne dystrophy and this finding of anabolic breakdown raises the question as to whether to treat muscular dystrophy with protease inhibitors. The paper closes with an attempt to relate the pathophysiology of muscular dystrophy to muscle performance and a section on muscle protein synthesis in muscular dystrophy. Dystrophic muscle is not simply muscle which is dying - since there is evidence of regenerative activity and increased protein synthesis - and this may therefore be the clue for a form of rational therapy.
Computed tomography (CT) scans of skeletal muscles of 3 patients with pseudohypertrophic muscular dystrophy are presented. Different patterns of muscle alterations and particularly of pseudohypertrophy are described. The significance of the radiological findings for clinical examination, electromyography, and needle biopsy is discussed.
SUMMARY Grey-scale ultrasonography can produce an image of the quadriceps muscle from which it is possible to measure its cross-sectional
area (CSA). The between-days coefficient of variation for quadriceps CSA (at mid-thigh) in 14 legs of seven subjects each
scanned on four days was reduced to 4.0% by averaging four scans on each day.
Bilateral scans (at the mid-thigh level) were used to measure the severity of quadriceps wasting in 21 otherwise healthy adult
patients with a difference in thigh circumference following unilateral knee immobilization or injury.
Quadriceps wasting as demonstrated by the scans was consistently more severe than the disparity in whole thigh cross-sectional
area at the same level or the disparity in anthropometric estimates of fat-free thigh volume. Investigations concerned with
changes in quadriceps muscle bulk must therefore use a technique (such as ultrasonography) which allows measurement of the
quadriceps itself.
Moppet, a rapid and accurate system for the measurement of muscle fibre cross sectional area A users guide to diagnostic ultrasound
- Jones Da
- Mf King
- Im Shirley
- R J Blackwell
- G Cusick
- D J Farman
- Vicary
- Fr
Jones DA, King MF, and Round JM: Moppet, a rapid and accurate system for the measurement of muscle fibre cross sectional area, J Physiol 305:5P, 1980. Shirley IM, Blackwell R J, Cusick G, Farman D J, and Vicary FR: A users guide to diagnostic ultrasound, Wells, England, 1978, Pitman Medical Publishing Co., Ltd., chap 3, pp 32-39.
Moppet, a rapid and accurate system for the measurement of muscle fibre cross sectional area
- Jones
A users guide to diagnostic ultrasound.
- Shirley IM
- Blackwell RJ
- Cusick G
- Farman DJ
- Vicary FR
A users guide to diagnostic ultrasound
- Shirley