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Skeletal muscle ultrasonography: Visual versus quantitative evaluation
Abstract
In this study, we compared the sensitivity and specificity of visual versus quantitative evaluation of skeletal muscle ultrasound in children suspected of having a neuromuscular disorder (NMD). Ultrasonography (US) scans of four muscles (biceps brachii, forearm flexors, quadriceps femoris, anterior tibial muscle) were made in 76 children. All images were visually evaluated using the Heckmatt criteria and quantitatively evaluated with computer-assisted grey-scale analysis of muscle echo intensity. Visual evaluation could achieve a sensitivity up to 71%, with a specificity of 92%. With quantification, a sensitivity of 87% accompanied by a specificity of 67% was found, but other diagnostic values could be achieved, depending on the cut-off point. Quantification resulted in a higher interobserver agreement (kappa 0.86) compared with visual evaluation (kappa 0.53). We conclude that quantification of echo intensity is a more objective and accurate method. Because it can achieve higher sensitivities, it is better-suited for the screening task in the diagnostic phase of children with a NMD. (E-mail: [email protected]
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... Hereby, NMUS might be of particular value for the detection, monitoring and, at least in part, outcome prediction in cases of ICUAW [29,30]. Beyond ultrasound, subsequent computational image analysis has also emerged in the last decade and might offer further improvement in diagnostic performance in ultrasonographic assessment [31,32]. Therefore, this narrative review aims to highlight the current scientific literature about the potential use of NMUS to diagnose and monitor ICUAW. ...
... In the absence of connective tissue, muscle fibers reflect lesser soundwaves back to the ultrasound probe, resulting in a relatively dark ultrasound image with a low echogenicity. It must be noted that healthy skeletal muscles can vary in their echogenicity, even without a pathological reason [29,32]. Most frequently, limb skeletal muscles have been assessed with NMUS in regard to investigating ICUAW. ...
... This method is, mostly, not implemented in current ultrasound machines, so quantification of ME using greyscale analysis requires a semi-automated secondary assessment by the examiner. Greyscale analysis has been validated in non-ICU and ICU patients with neuromuscular disorders [32,80], whereby the accuracy depends on the size of the measured image area [81]. Furthermore, software-based greyscale analysis has also been investigated in patients with ICUAW [29,45,49]. ...
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.
... 3 Previous studies showed that the Heckmatt scale has moderate to good diagnostic values for detecting NMD. 4,5 In contrast, quantitative MUS (QMUS) measures the mean grayscale value of the muscle region of interest (ROI), and compares this muscle echogenicity to a reference value. Subsequently, a standardized echogenicity (z-score) can be calculated, which denotes the number of SDs of the measured echogenicity from the predicted echogenicity. ...
... 7,8 Also the interrater reliability is greater for QMUS than for the visual assessment. 4 Unfortunately, QMUS is critically dependent on the hardware of ultrasound systems and post-processing. Differences in each of these alter echogenicity, so that images and reference values from different systems or probes cannot be directly compared. ...
... Depending on the referral question, one of four different screening protocols was used (see Supporting Information Methods, which are available online). 1 A subset of the patients underwent MUS using a research-specific protocol, as described previously. 4 ...
Introduction / aims:
Visual and quantitative muscle ultrasound are both valid diagnostic tools in neuromuscular diseases. To optimize muscle ultrasound evaluation and facilitate its use in neuromuscular disease, we examined the correlation between visual and quantitative muscle ultrasound analysis and their pitfalls.
Methods:
Retrospective data from 994 patients with 13562 muscle ultrasound images were analyzed. Differences in echogenicity z-score distribution per Heckmatt grade and corresponding correlation coefficients were calculated.
Results:
Overall there was a correlation of 0.60 between the two scoring systems, with a gradual increase in z-score with increasing Heckmatt grades and vice versa. Patients with a neuromuscular disorder had higher Heckmatt grades (p < 0.001) and z-scores (median z-score = 0.30, p < 0.001) than patients without. The highest Heckmatt grades and z-scores were found in patients with either a dystrophy or inflammatory myopathy (both median Heckmatt grade of 2 and median Z score of 0.74 and 1.20 respectively). Discrepant scores were infrequent (< 2%), but revealed important pitfalls in both grading systems.
Discussion:
Visual and quantitative muscle ultrasound are complementary techniques to evaluate neuromuscular disease and have a moderate positive correlation. Importantly, we identified specific pitfalls for visual and quantitative muscle ultrasound and how to overcome them in clinical practice.
... Heckmatt scale is a four-point visual grading scale based on gray-scale appearance [47]. This visual evaluation scale has shown high sensitivity and high inter-observer agreement [61]. Interestingly, echogenicity can also be evaluated using quantitative methods. ...
... When assessing muscle wasting, clinicians select specific muscles based on clinical relevance and accessibility. The most commonly evaluated muscles are in the limbs and include the quadriceps, rectus femoris, and the anterior compartment muscles of the thigh [61,[77][78][79]. Ultrasonography typically involves using a high-frequency ultrasound probe oriented to obtain longitudinal or transverse images of the muscle of interest. ...
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.
... Muscle US can be performed both by qualitative and quantitative methods. Though the first modality is suitable for a routine examination, quantitative muscle US (QMUS) guarantees a lower operator-dependency and provides more suitable results for statistical analysis and research [9,10]. In particular, QMUS allows to measure muscle EI by computer-assisted grey-scale analysis, which offers higher sensitivity and reliability compared to visual evaluation in muscle imaging in numerous NMDs [6,11]. ...
... In each stored image, we manually selected a region of interest (ROI) using the calliper function, to include as much muscle mass as possible, excluding the bone and possibly the muscular fascia, which have high EI. The standard histogram function was used to translate the median EI of the ROI into a numeric value between 0 (= black) and 255 (= white) [10,21]. Quantitative evaluation of all measurements was performed by a technician, blind both to clinical and MRI data. ...
Introduction
Muscle ultrasound is a fast, non-invasive and cost-effective examination that can identify structural muscular changes by assessing muscle thickness and echointensity (EI) with a quantitative analysis (QMUS). To assess applicability and repeatability of QMUS, we evaluated patients with genetically confirmed facioscapulohumeral muscular dystrophy type 1 (FSHD1), comparing their muscle ultrasound characteristics with healthy controls and with those detected by MRI. We also evaluated relationships between QMUS and demographic and clinical characteristics.
Materials and methods
Thirteen patients were included in the study. Clinical assessment included MRC sum score, FSHD score and The Comprehensive Clinical Evaluation Form (CCEF). QMUS was performed with a linear transducer scanning bilaterally pectoralis major , deltoid , rectus femoris , tibialis anterior and semimembranosus muscles in patients and healthy subjects. For each muscle, we acquired three images, which were analysed calculating muscle EI by computer-assisted grey-scale analysis. QMUS analysis was compared with semiquantitative 1.5 T muscle MRI scale.
Results
All muscles in FSHD patients showed a significant increased echogenicity compared to the homologous muscles in healthy subjects. Older subjects and patients with higher FSHD score presented increased muscle EI. Tibialis anterior MRC showed a significant inverse correlation with EI. Higher median EI was found in muscles with more severe MRI fat replacement.
Conclusions
QMUS allows quantitative evaluation of muscle echogenicity, displaying a tight correlation with muscular alterations, clinical and MRI data. Although a confirmation on larger sample is needed, our research suggests a possible future application of QMUS in diagnosis and management of muscular disorders.
... Dagegen findet sich bei ICUAW eine vermehrte ME der gesamten Muskel-CSA [20]. 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]). ...
... Die Genauigkeit der Graustufenanalyse ist abhängig von der Größe des eingeschlossenen Bildbereichs [6]. Beide Verfahren weisen eine gute bis sehr gute Intra-und Interrater-Reliabilität auf [38,46], auch bei weniger erfahrenen Untersuchern [1]. Bei Intensivpatienten kann mehrheitlich eine Zunahme der ME im Behandlungsverlauf beobachtet werden [5,7,14,37,38,43]. ...
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.
... Meanwhile, gray-scale analysis showed a sensitivity of 87% and specificity of 67% and higher inter-observer agreement than the visual method. Given the higher sensitivity and higher inter-observer agreement, gray-scale analysis may provide an effective screening tool for diagnosis of neuromuscular disease in children [19]. ...
... A common method involves obtaining the mean grayscale level within a manually selected region of interest (ROI) of an image and comparing it to reference values obtained from a specific muscle. The measured gray-scale values can be transformed into Z-scores, which represent the standard deviations from the reference values for the mean echogenicity of that muscle (Z-score of 0 being identical to the mean echogenicity value, Z-score of 1 being one standard deviation from the mean echogenicity value, Z-score of 2 being two standard deviations from the mean echogenicity value) [19]. The mean gray-scale values can be calculated from pixel histogram analysis (e.g., ImageJ https://imagej.nih.gov/ij/ ...
Ultrasound (US) is an important imaging tool for skeletal muscle analysis. The advantages of US include point-of-care access, real-time imaging, cost-effectiveness, and absence of ionizing radiation. However, US can be highly dependent on the operator and/or US system, and a portion of the potentially useful information carried by raw sonographic data is discarded in image formation for routine qualitative US. Quantitative ultrasound (QUS) methods provide analysis of the raw or post-processed data, revealing additional information about normal tissue structure and disease status. There are four QUS categories that can be used on muscle and are important to review. First, quantitative data derived from B-mode images can help determine the macrostructural anatomy and microstructural morphology of muscle tissues. Second, US elastography can provide information about muscle elasticity or stiffness through strain elastography or shear wave elastography (SWE). Strain elastography measures the induced tissue strain caused either by internal or external compression by tracking tissue displacement with detectable speckle in B-mode images of the examined tissue. SWE measures the speed of induced shear waves traveling through the tissue to estimate the tissue elasticity. These shear waves may be produced using external mechanical vibrations or internal “push pulse” ultrasound stimuli. Third, raw radiofrequency signal analyses provide estimates of fundamental tissue parameters, such as the speed of sound, attenuation coefficient, and backscatter coefficient, which correspond to information about muscle tissue microstructure and composition. Lastly, envelope statistical analyses apply various probability distributions to estimate the number density of scatterers and quantify coherent to incoherent signals, thus providing information about microstructural properties of muscle tissue. This review will examine these QUS techniques, published results on QUS evaluation of skeletal muscles, and the strengths and limitations of QUS in skeletal muscle analysis.
... 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.
... Second, the Heckmatt scale is graded mainly by visual (subjective) assessment [8]. Third, differentiating grade 2 from grade 3 is a major drawback due to the lack of clear definition regarding decreased bony reflection [9]. Thus, an objective and quantitative US parameter is imperative for following muscle changes and motor functions in Pompe disease. ...
... Backscatter analysis, derived from the measurement of the average grayscale level, can also quantify muscle texture [11]. Pillen et al. have tried to transform the measured echogenicity into z-scores to improve detection of the abnormal muscle [9]. The sensitivity to detect abnormal muscle with echogenicity quantification was 87% compared to 71% with visual detection. ...
Background
Pompe disease usually has muscle weakness due to glycogen accumulation. Heckmatt scale is commonly used to grade the pertinent findings of ultrasound. Nonetheless, it is difficult to detect subtle changes of the muscle. Besides, no ultrasonographic parameter has been proposed to predict the motor functions of Pompe disease. Therefore, we aimed to find out an ultrasonographic parameter that can quantify the muscle involvement and correlate with the motor functions in Pompe disease.
Methods
Eighteen patients with Pompe disease were enrolled. The echo heterogeneity index (standard deviation divided by mean echogenicity values by ImageJ analysis) and shear modulus were recorded from rectus femoris, biceps femoris, tibialis anterior, medial gastrocnemius, biceps brachii and triceps brachii muscles. Motor functions, including manual muscle strength, 6-min walk and four-limb stair climb tests were assessed. Correlations between ultrasonographic parameters and Heckmatt scale and motor functions were analyzed.
Results
The echo heterogeneity index, but not the shear modulus, was negatively correlated with the Heckmatt scale rating in all muscles. The echo heterogeneity indices of tibialis anterior (r = 0.698, p = 0.008) and medial gastrocnemius (r = 0.615, p = 0.025) muscles showed positive correlations with the walking distance. Besides, the echo heterogeneity indices of four lower limb muscles were negatively correlated with the duration of stair climbing.
Conclusion
The echo heterogeneity index but not the shear modulus can be used to quantitatively describe the muscle involvement in Pompe disease. In addition, lower echo heterogeneity indices of lower limb muscles are associated with worse motor functions in these patients.
... Both approaches can assess muscle thickness, intramuscular fat infiltration, and other biochemical indices of muscle quality since muscle and fat are clearly distinguished [56,58]. Variations in echo intensity (EI) are associated with increased intramuscular fiber and fat tissue [59][60][61][62][63][64]. Researchers who employed computeraided gray scale analysis to determine muscle quality say the EI increases intramuscular adipose and fibrous tissue. ...
... Researchers who employed computeraided gray scale analysis to determine muscle quality say the EI increases intramuscular adipose and fibrous tissue. In recent years, pixel/voxel threshold distinctions between muscle and other tissues have been established semiautomatically [60][61][62][63][64]. In addition to frailty, quantitative MRI data may identify variations in muscle function across age groups [65][66][67][68][69]. Using automated subcutaneous fat and muscle segmentation, multiparametric MRI has recently shown promise in measuring subcutaneous adipose tissue (SAT) and intermuscular adipose tissue (IMAT) [70]. ...
Sarcopenia is characterized by loss of muscle mass, altered muscle composition, fat and fibrous tissue infiltration, and abnormal innervation, especially in older individuals with immune-mediated rheumatic diseases (IMRDs). Several techniques for measuring muscle mass, strength, and performance have emerged in recent decades. The portable dynamometer and gait speed represent the most frequently used tools for the evaluation of muscle strength and physical efficiency, respectively. Aside from dual-energy, X-ray, absorptiometry, and bioelectrical impedance analysis, ultrasound (US) and magnetic resonance imaging (MRI) techniques appear to have a potential role in evaluating muscle mass and composition. US and MRI have been shown to accurately identify sarcopenic biomarkers such as inflammation (edema), fatty infiltration (myosteatosis), alterations in muscle fibers, and muscular atrophy in patients with IMRDs. US is a low-cost, easy-to-use, and safe imaging method for assessing muscle mass, quality, architecture, and biomechanical function. This review summarizes the evidence for using US and MRI to assess sarcopenia.
... EG can be quantified using histogram-based gray-scale analysis, which calculates the mean gray value of a region of interest. Based on normative values of muscle thickness and EG, z-scores can be calculated to compare QMUS data of affected and unaffected individuals [8]. An increased EG in muscles indicates unfavorable changes in the muscle architecture, which can lead to muscle dysfunction [9,10]. ...
Purpose
Quantitative muscle ultrasound (QMUS) is a patient friendly tool for examining orofacial muscles. Resection of tissue can have an effect on the architecture and function of these muscles. The aim of this study is to investigate the feasibility of visualizing and quantifying muscle changes in postoperative oral cancer patients and to relate the findings to tumor and patient characteristics.
Methods
Adult patients with a resected first primary pT1 or T2 oral squamous cell carcinoma, at least one year post operatively, where included. Ultrasound data were collected of the geniohyoid muscle, digastric muscles, masseter muscle, transverse muscle and genioglossus muscle. Ultrasound images were labeled as clearly visible, questionable or unclear. Of the clear muscles, echogenicity and muscle thickness were measured.
Results
37 patients were included. The masseter muscle was clearly visible in all ultrasound images, both intrinsic tongue muscles had the lowest visibility (45.9%). There was a significant correlation between visibility and tumor localization for the genioglossus ( p = 0.029). Age correlated with the visibility of the genioglossus muscle, BMI with the genioglossus and transverse muscles. Echogenicity and muscle thickness of the clearly identified muscles did not differ from normative values.
Conclusion
QMUS of orofacial muscles is feasible in postoperative oral cancer patients with relatively small tumor sizes. Tongue resections negatively affected the visibility of the two intrinsic tongue muscles. These preliminary results for particular muscles indicate that the use of ultrasound might be promising in oral cancer patients to help determine targeted goals in post-operative rehabilitation.
... Muscle echogenicity depends on the contingent of connective tissue, the orientation of muscle fibers, the subcutaneous fat, age, and sex. Echogenicity can be measured semi-quantitatively using the Heckmatt score (39) or quantitatively using gray scale analysis (40). ...
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.
... For example, high EI values reflect fibrotic 2 muscles that are rich in fat infiltration as observed in Duchenne muscular dystrophy [11]. As such, EI may be a valuable add-on method to the screening and diagnosis, as well as the monitoring of neuromuscular diseases [12,13]. ...
Background: According to EWGSOP2, the diagnosis of sarcopenia is confirmed when in addition to low muscle strength, low muscle quantity or quality is present. Echo intensity (EI) determined by muscle ultrasound (US) has been proposed as an efficient method for the assessment of muscle quality. The effect of changing various US parameter settings on EI remains unclear. Therefore, the aim of this study was to assess the differences between EI values obtained by adjusting parameter settings over their entire range in a sample of middle-aged healthy subjects. Methods: Thirty-two repeated US scans of rectus femoris (RF) and rectus abdominis (RA) muscles were taken in eight men and three women with a portable Mindray M7 premium US machine, working in an Extended field-of-view, B-Mode setup, equipped with a linear 5.0-10.0 MHz transducer. The following US parameters and settings were fixed: gain 60dB, depth 6.5cm, and frequency 10 MHz. Readily adjustable parameters were dynamic range (DR), gray map (GM), line density, persistence, and IClear. A default setting DR65 was chosen as the reference setting. For each of the parameters, the settings of one single parameter of interest was changed over its entire range following a standardized protocol. The EI values were calculated using the open-source software ImageJ. Repeated measures analyses were performed to evaluate the effect of parameter settings on EI. Linear interpolation was used to determine non-significant ranges across a given parameter. Results: For the RF muscle, the EI values were significantly different across DR (p<0.001), GM (p<0.001), and IClear (p<0.001). Post hoc analysis confirmed the differences within these three settings. Echo intensity values within the range of DR55 to DR80 were not significantly different. For the RA muscle, the EI values were significantly different across DR (p=0.004) and GM (p=0.030). Post hoc pairwise comparisons revealed no significant difference with the default setting, except for DR150 (p=0.042). Conclusion: We showed that EI values differ across the DR and GM range, especially in the RF. We suggest using a DR setting within its midrange to minimize the effect of machine setting-dependent factors on EI values. These findings reconfirm the need for standardization of ultrasound echo intensity settings when applied for diagnostic purposes of muscle quality.
... For example, high EI values reflect fibrotic muscles that are rich in fat infiltration as observed in Duchenne muscular dystrophy [17]. As such, EI may be a valuable add-on method to the screening and diagnosis as well as the monitoring of neuromuscular diseases [18,19]. ...
Echo intensity determined by muscle ultrasound has been proposed as an efficient method for the assessment of muscle quality. The influence of changing ultrasound parameter settings on echo intensity values was assessed using a standardized approach. In this repeated measures cross-sectional study, sixteen repeated scans of rectus femoris, gracilis, and rectus abdominis were taken in 21 middle-aged persons with a portable Mindray M7 premium ultrasound machine equipped with a linear 5.0–10.0 MHz transducer. The settings of three parameters were fixed: gain, depth, and frequency. The settings of the following adjustable parameters were changed over their entire range: dynamic range, gray map, line density, persistence, and IClear. Repeated measures analyses were performed to evaluate the effect of changing the settings on echo intensity values. In all three muscles, dynamic range, gray map, and IClear correlated significantly (rrm-values ranging between −0.86 and 0.45) with echo intensity. In all three muscles, the echo intensity values differed significantly across the dynamic range (p < 0.013), gray map (p < 0.003), and IClear (p < 0.003). In middle-aged subjects, echo intensity values of lower limb and trunk muscles are significantly related to ultrasound parameters and significantly differ across their respective setting range. For the assessment of muscle quality through ultrasound, it is suggested to fix parameter settings within their midrange in order to minimize the effect of setting-dependent factors on EI values.
... Again, such effects will lead to bias, and to systematic under-or over-estimation of skeletal muscle echo intensity, unless adjustment is performed. One group researching neuromuscular disorders in children visually corrected for pennation angle by adjusting the probe over the muscle until the echo intensity was highest 37,38 . Another study even measured echo intensity alteration with a probe tilt up to 6° in both directions in relation to the skin and proposed that the operator shall minimize the probe tilt during muscle examination 39 . ...
This study aimed to validate the concept of spatial gain sonography for quantifying texture-related echo intensity in B-mode ultrasound of skeletal muscle. Fifty-one bovine muscles were scanned postmortem using B-mode ultrasonography at varying fascicle probe angles (FPA). The relationship between mean gray values (MGV) and FPA was fitted with a sinusoidal and a linear function, the slope of which was defined as tilt echo gain (TEG). Macroscopic muscle cross sections were optically analyzed for intramuscular connective tissue (IMCT) content which was plotted against MGV at 0° FPA (MGV_00). MGV peaked at FPA 0°. Sine fits were superior to linear fits (adjusted r²-values 0.647 vs. 0.613), especially for larger FPAs. In mixed models, the pennation angle was related to TEG (P < 0.001) and MGV_00 (P = 0.035). Age was relevant for MGV_00 (P < 0.001), but not TEG (P > 0.10). The correlation between the IMCT percentage and MGV_00 was significant but weak (P = 0.026; adjusted r² = 0.103). The relationship between fascicle probe angle and echo intensity in B-mode ultrasound can be modeled more accurately with a sinusoidal but more practically for clinical use with a linear fit. The peak mean gray value MGV_00 can be used to compare echo intensity across muscles without the bias of pennation angle.
... Increased echogenicity on USG reflects increased intramuscular adipose tissue, inflammation, or fibrosis and causes decreased muscle strength and altered stiffness 17 . However, Pillen et al. reported a relatively low reproducibility of subjective EI evaluation compared to the quantification of muscle EI 18 . ...
This study aimed to develop and evaluate a sarcopenia prediction model by fusing numerical features from shear-wave elastography (SWE) and gray-scale ultrasonography (GSU) examinations, using the rectus femoris muscle (RF) and categorical/numerical features related to clinical information. Both cohorts (development, 70 healthy subjects; evaluation, 81 patients) underwent ultrasonography (SWE and GSU) and computed tomography. Sarcopenia was determined using skeletal muscle index calculated from the computed tomography. Clinical and ultrasonography measurements were used to predict sarcopenia based on a linear regression model with the least absolute shrinkage and selection operator (LASSO) regularization. Furthermore, clinical and ultrasonography features were combined at the feature and score levels to improve sarcopenia prediction performance. The accuracies of LASSO were 70.57 ± 5.00–81.54 ± 4.83 (clinical) and 69.00 ± 4.52–69.73 ± 5.47 (ultrasonography). Feature-level fusion of clinical and ultrasonography (accuracy, 70.29 ± 6.63 and 83.55 ± 4.32) showed similar performance with clinical features. Score-level fusion by AdaBoost showed the best performance (accuracy, 73.43 ± 6.57–83.17 ± 5.51) in the development and evaluation cohorts, respectively. This study might suggest the potential of machine learning fusion techniques to enhance the accuracy of sarcopenia prediction models and improve clinical decision-making in patients with sarcopenia.
... Echo intensity was assessed based on a computer-assisted 8-bit grayscale analysis and rated from 0 (black) to 255 (white) [6-9, 12-16, 20]. Greater intramuscular adipose tissue was indicated by higher echo intensity [24]. ...
Background
Recent studies reported that an increase in intramuscular adipose tissue of the quadriceps in older patients negatively affects the recovery of activities of daily living (ADL) more than the loss of muscle mass. However, whether intramuscular adipose tissue of the quadriceps in older patients with aspiration pneumonia is related to ADL recovery remains unclear. This study aimed to determine the relationship between intramuscular adipose tissue of the quadriceps and ADL recovery in older patients with aspiration pneumonia.
Methods
Thirty-nine older inpatients who were diagnosed with aspiration pneumonia participated in this prospective study. The main outcome of this study was ADL at discharge. ADL were assessed using the Barthel Index (BI). The intramuscular adipose tissue and muscle mass of the quadriceps were evaluated at admission using echo intensity and muscle thickness observed on ultrasound images. A multiple linear regression analysis was performed to confirm whether the quadriceps echo intensity was related to the BI score at discharge, even after adjusting for confounding factors.
Results
The medians [interquartile range] of the BI score at admission and discharge were 15.0 [0.0–35.0] and 20.0 [5.0–55.0], respectively. The BI score at discharge was significantly higher than that at admission (p = 0.002). The quadriceps echo intensity (β = − 0.374; p = 0.036) and BI score at admission (β = 0.601; p < 0.001) were independently and significantly related to the BI score at discharge (R² = 0.718; f² = 2.546; statistical power = 1.000). In contrast, the quadriceps thickness (β = − 0.216; p = 0.318) was not independently and significantly related to the BI score at discharge.
Conclusions
Increased intramuscular adipose tissue of the quadriceps at admission is more strongly and negatively related to ADL recovery at discharge than the loss of muscle mass among older patients with aspiration pneumonia. Interventions targeting the intramuscular adipose tissue of the quadriceps may improve ADL among these patients.
... Echo intensity was determined by performing a computer-assisted 8-bit gray-scale analysis, and the mean echo intensity of the regions of interest was rated from 0 (black) to 255 (white) [2e11,18e20]. A higher echo intensity indicates a greater intramuscular adipose tissue [21]. ...
... Analizo izvedemo s pomočjo funkcije histograma, ki jo omogočajo številne programske opreme za obdelavo slik. Tovrstna kvantitativna analiza sive skale se je izkazala za bolj natančno od vizualne subjektivne ocene UZ slik, vendar zahteva več časa in določitev normalnih referenčnih vrednosti (44). Metoda merjenja ehogenosti ima več omejitev. ...
Sarkopenija je izguba mišične mase in funkcije, ki zmanjša kakovost življenja, povzroči fizično oslabelost in je povezana z večjo umrljivostjo. Za postavitev zgodnje diagnoze in za uspešno zdravljenje sarkopenije so potrebne varne, dostopne in natančne diagnostične metode. Ultrazvočna slikovna preiskovalna metoda se vse pogosteje uporablja za oceno mišične mase in kakovosti mišic. S pomočjo različnih ultrazvočnih parametrov lahko sklepamo o količini mišične mase kot tudi o kakovosti mišičnega tkiva. Z uporabo standardiziranih protokolov opravljanja meritev lahko dosežemo večjo natančnost in ponovljivost preiskave. Pomanjkanje jasno določenih mejnih vrednosti in nepopolna standardizacija protokolov in ponekod slaba korelacija parametrov z dejansko fizično zmogljivostjo bolnikov za zdaj še zavirajo širšo uporabo ultrazvočne preiskave v kliničnem okolju. Kljub temu z naraščujočim številom raziskav na tem področju ultrazvočna preiskava pridobiva veljavo pri vsakdanji klinični obravnavi sarkopeničnih bolnikov.
... -12,14,15 . Higher echo intensity indicates greater intramuscular adipose tissue.20 . ...
This study aimed to examine the relationships between intramuscular adipose tissue and muscle mass of the quadriceps at post-acute hospital admission and the low rate of home discharge. This prospective study included 389 inpatients aged ≥ 65 years. Patients were divided into two groups according to the destination: home discharge (n = 279) and no-home discharge (n = 110) groups. The primary outcome was hospital discharge destination (home discharge or not). Intramuscular adipose tissue and muscle mass of the quadriceps were assessed at post-acute hospital admission using echo intensity and muscle thickness on ultrasound images, respectively. Logistic regression analysis was used for determining whether quadriceps echo intensity is related to home discharge. Quadriceps echo intensity was significantly and independently associated with home discharge (odds ratio [per 1 SD increase] = 1.43, p = 0.045). Quadriceps thickness was not associated with home discharge (odds ratio [per 1 SD increase] = 1.00, p = 0.998). Our study indicates that greater intramuscular adipose tissue of the quadriceps in older inpatients at post-acute hospital admission is more strongly related to a low rate of home discharge than a loss of muscle mass.
... The camera was turned on 30 minutes before the test to allow sensor stabilization following the manufacturer's guidelines and the images were recorded perpendicular to the region of interest. Images were selected and visualized in software (APOLLO ® version 1.2, Brazil) for analysis by the thermopixelgraphy method (TPG) [42][43][44]. The emissivity value adopted for human skin was 0.98 and a black background was used [45][46][47]. ...
1. Abstract High-intensity efforts represent 25% of the distance in a soccer match. This demand can result in fatigue, that could be assessed by load monitoring. Ultrasonography (US) is gaining popularity for clinical evaluation in soccer clubs and Infrared Thermography (IRT) presents skin temperature (ST) in real-time. There are no studies of their combined use in soccer. 28 male soccer players participated in this study (age 18.0±2 years, bodyweight 74.3±7.3kg). All athletes who participated in 75% of the total minutes or had some pain during the games were referred for evaluations involving IRT, biomarkers and VAS scale. Athletes who presented VAS pain ≥ 6 and Thermograms with unilateral hypothermic changes in the same limb and anatomical region were referred for evaluation by US. Data normality was verified using the Shapiro-Wilk test. Differences between the maximum, mean, and minimum temperature of the affected and healthy sides were analyzed using the T-test for independent groups. A α<0.05 was adopted as the level of significance. The US images of the contralateral were not diagnosed with injuries and no temperature reductions were found within the ROIs. In all, there were seven diagnoses of edema and three grade I injuries. 2. Introduction Soccer is a sport in which performance depends on physical, technical , tactical, and psychological factors [1], characterized by intermittent and high-intensity efforts [2]. High-intensity actions consist of sprints, accelerations and decelerations come to represent 25% of the distance covered in a match [3]. Such physical demand can cause skeletal muscle damage, which induces a decrease in neuromuscular performance and extravasation of cellular proteins into the bloodstream, as a consequence, it takes longer than
... 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]. ...
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.
... 16 Mean greyscale of this ROI was expressed as a value between 0 (= black) and 255 (= white), where higher values indicate more fat or fibrous muscle infiltration, i.e. poorer muscle quality. 17 The average of three measurements of RF-ECHO was used for analysis. ...
Background
Cystic fibrosis (CF) is characterized by CF transmembrane conductance regulator (CFTR) dysfunction. CFTR protein is expressed in human skeletal muscle; however, its impact on skeletal muscle is unknown. The objectives of this study were to compare quadriceps muscle size and quality between adults with various severities of CFTR protein dysfunction.
Methods
We conducted a prospective, cross-sectional study comparing 34 adults with severe versus 18 with mild CFTR protein dysfunction, recruited from a specialized CF centre. Ultrasound images of rectus femoris cross-sectional area (RF-CSA) and quadriceps layer thickness for muscle size, and rectus femoris echogenicity (RF-ECHO) (muscle quality) were obtained. Multivariable linear regression models were developed using purposeful selection technique.
Results
People with severe CFTR protein dysfunction had larger RF-CSA by 3.22 cm ² , 95% CI (1.03, 5.41) cm ² , p=.0049], after adjusting for oral corticosteroid use and Pseudomonas aeruginosa colonization. However, a sensitivity analysis indicated that the result was influenced by the specific confounders being adjusted for in the model. We did not find any significant differences in quadriceps layer thickness or RF-ECHO between the two groups.
Conclusion
We found no differential impact of the extent of diminished CFTR protein activity on quadriceps muscle size or quality in our study cohort. Based on these findings, CFTR mutation status cannot be used differentiate leg muscle size or quality in people with CF.
... Echo intensity was examined by performing a computer-assisted 8-bit gray-scale analysis, and the mean echo intensity of the regions of interest was rated from 0 (black) to 255 (white) [21, 23-33]. A higher echo intensity indicates greater intramuscular adipose tissue [37]. ...
Background & aim:
A recent study reported that the increase in intramuscular adipose tissue of the quadriceps in older inpatients is related to a decreasing degree of recovery in swallowing ability compared to the loss of muscle mass. However, whether the association remains true in case of aspiration pneumonia is unclear. Therefore, this study aimed to examine the relationship between the degree of recovery in swallowing ability and intramuscular adipose tissue in the quadriceps of older inpatients with aspiration pneumonia.
Methods:
This prospective study included 39 older patients with aspiration pneumonia. Swallowing ability was assessed using the Food Intake Level Scale (FILS). The indicators for the degree of recovery in swallowing ability were FILS at discharge and change in FILS. A greater change in FILS indicates a greater improvement in swallowing ability. Intramuscular adipose tissue and muscle mass of the quadriceps were evaluated at admission using echo intensity and muscle thickness on ultrasound images, respectively. Multiple regression analysis was used to determine whether the echo intensity of the quadriceps was independently and significantly related to FILS at discharge and the change in FILS. Independent variables were age, sex, days from disease onset, echo intensity and muscle thickness of the quadriceps, subcutaneous fat thickness of the thigh, FILS at admission, and number of units of rehabilitation therapy.
Results:
Echo intensity of the quadriceps (β = -0.363, p = 0.012) and FILS at admission (β = 0.556, p < 0.001) were independently and significantly associated with FILS at discharge (R2 = 0.760, f2 = 3.167, statistical power = 1.000). Similar variables (echo intensity of the quadriceps [β = -0.498, p = 0.012] and FILS at admission [β = -0.635, p < 0.001]) were independently and significantly related to change in FILS (R2 = 0.547, f2 = 1.208, statistical power = 0.998). Quadriceps muscle thickness was not independently and significantly related to FILS at discharge and change in FILS.
Conclusion:
Our results indicate that intramuscular adipose tissue of the quadriceps in older inpatients with aspiration pneumonia is more strongly related to the degree of recovery in swallowing ability (that is, swallowing ability at discharge and change in swallowing ability) than muscle mass, and patients who have high intramuscular adipose tissue of the quadriceps at admission have a lower degree of recovery in swallowing ability.
... Despite being the current gold standard for quantifying muscle mass in cirrhotic patients, Computed Tomography (CT) is not practical for muscle evaluation because of its high cost, high radiation exposure, and logistical issues. Ultrasound detection of quadriceps muscle thickness has been recently presented as a more convenient bedside method to assess sarcopenia (6) . ...
... These changes, as a result of denervation, have been studied successfully with QMUS [17]. Quantification of muscle echogenicity using greyscale analysis has a high inter-observer agreement than visual evaluation, with good clinical validity for detecting neuromuscular pathology [18]. Greyscale analysis requires minimal training and increases diagnostic sensitivity to 92% compared to visual image grading [17,19]. ...
Background
It is assumed that in patients with diabetic neuropathy, muscle denervation can result in shoulder disorders. Muscle denervation will lead to changes in muscle architecture, which can be assessed by quantitative muscle ultrasound (QMUS). The aim was to investigate whether increased muscle echogenicity, as a sign of neuropathy, is more often present in patients with shoulder pain who have type 2 diabetes mellitus (T2DM) than in those without.
Methods
Sixty-six patients with T2DM and 23 patients without diabetes mellitus (DM) having shoulder pain were included. Quantitative muscle ultrasound images were obtained bilaterally from the biceps brachii, deltoid, and supra- and infraspinatus muscles. The mean echogenicity (muscle ultrasound grey value) was transformed into z-scores and compared to reference values obtained from 50 healthy participants. Associations between muscle echogenicity and clinical variables were explored.
Results
In painful shoulders of both patients with T2DM and patients without DM, mean echogenicity z-scores of all muscles were significantly increased compared to healthy controls. No significant differences in echogenicity between patients with T2DM and those without DM were found. In patients with T2DM, a distal symmetric polyneuropathy was significantly associated with increased echogenicity of all muscles except the infraspinatus muscle.
Conclusions
These findings indicate that patients with painful shoulders, irrespective of having T2DM, seem to have abnormal shoulder muscles. Future studies are needed to elucidate whether neuropathy or other conditions lead to these muscle changes.
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
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.
Spasticity is a complex neurological disorder, causing significant physical disabilities and affecting patients' independence and quality of daily lives. Current spasticity assessment methods are questioned for their non-standardized measurement protocols, limited reliabilities, and capabilities in distinguishing neuron or non-neuron factors in upper motor neuron lesion. A series of new approaches are developed for improving the effectiveness of current clinical used spasticity assessment methods with the developing technology in biosensors, robotics, medical imaging, biomechanics, telemedicine, and artificial intelligence. We investigated the reliabilities and effectiveness of current spasticity measures employed in clinical environments and the newly developed approaches, published from 2016 to date, which have the potential to be used in clinical environments. The new spasticity scales, taking advantage of quantified information such as torque, or echo intensity, the velocity-dependent feature and patients' self-reported information, grade spasticity semi-quantitatively, have competitive or better reliability than previous spasticity scales. Medical imaging technologies, including near-infrared spectroscopy, magnetic resonance imaging, ultrasound and thermography, can measure muscle hemodynamics and metabolism, muscle tissue properties, or temperature of tissue. Medical imaging-based methods are feasible to provide quantitative information in assessing and monitoring muscle spasticity. Portable devices, robotic based equipment or myotonometry, using information from angular, inertial, torque or surface EMG sensors, can quantify spasticity with the help of machine learning algorithms. However, spasticity measures using those devices are normally not physiological sound. Repetitive peripheral magnetic stimulation can assess patients with severe spasticity, which lost voluntary contractions. Neuromusculoskeletal modeling evaluates the neural and non-neural properties and may gain insights into the underlying pathology of spasticity muscles. Telemedicine technology enables outpatient spasticity assessment. The newly developed spasticity methods aim to standardize experimental protocols and outcome measures and enable quantified, accurate, and intelligent assessment. However, more work is needed to investigate and improve the effectiveness and accuracy of spasticity assessment.
Background:
Camptocormia (CC) is the forward-bending of the spine of more than 30 degrees that can be found in Parkinson's disease (PD) as a disabling complication. Detection of changes in paraspinal lumbar musculature in CC is of value for choosing treatment strategies.
Objective:
To investigate whether these changes can be detected using muscle ultrasonography (mUSG).
Methods:
Age and sex-matched groups comprised 17 PD patients with CC (seven acute, PD-aCC; 10 chronic PD-cCC), 19 PD patients with no CC, and 18 healthy controls (HC). Lumbar paravertebral muscles (LPM) on both sides were assessed using mUSG by two different raters blinded to the group assignment. Groups were compared with regard to the linear measurements of the muscle thickness as well as semi-quantitative and quantitative (grayscale) analyses of muscle echogenicity using a univariate general linear model.
Results:
All assessments showed substantial interrater reliability. The PD-cCC group had significantly thinner LPM compared to groups with no CC (PD and HC). Groups of PD-aCC and PD-cCC differed from the groups of no CC in quantitative and semi-quantitative analyses of LPM echogenicity, respectively.
Conclusion:
Assessment of LPM in PD patients with CC can be reliably performed using mUSG. Also, mUSG may be used as a screening tool to detect CC-related changes in thickness and echogenicity of the LPM in patients with PD.
Our aim was to establish correlations between GSGC (Gait, Stairs, Gower, Chair) scores and ultrasonographic (US) findings of rectus femoris muscle (RF) and to study correlation between pulmonary function tests (PFT) and diaphragmatic muscles thickness in ambulatory boys with Duchenne muscular dystrophy (DMD). Twenty-four ambulatory boys with DMD were included. Their motor functions were assessed using GSGC scale. All the participants underwent PFT. US was used to assess RF quantitatively (gray scale analysis) and semiquantitatively (modified Heckmatt score) besides assessment of diaphragmatic muscle thickness. Patients with grade IV modified Heckmatt scale had the worst functional performance compared with grade III and II evidenced by having the highest total GSGC score (p < 0.01), worst gait, stairs climbing, chair rising scores, and the longest time for rising from floor (p < 0.05). A significant positive correlation was detected between forced expiratory volume in 1s/ forced vital capacity and right diaphragmatic muscle thickness. GSGC score positively correlated with RF US findings (quantitative gray scale analysis). GSGC score is a successful tool that could be used for clinical evaluation of patients with DMD. Diaphragmatic US introduces an option for screening and monitoring of restrictive respiratory pattern in patients with DMD after determining the reference values of diaphragmatic muscle thickness in different ages.
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.
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.
Background & aims:
Whether there is a longitudinal relationship between muscle mass and intramuscular adipose tissue of the quadriceps at different activities of daily living (ADL) levels remains unclear. This study aimed to examine the longitudinal relationship between muscle mass and intramuscular adipose tissue of the quadriceps in older inpatients at different ADL levels.
Methods:
This prospective cohort study was hospital-based and included 198 inpatients aged ≥65 years. Ultrasound images were acquired using B-mode ultrasound imaging. Muscle mass and intramuscular adipose tissue of the quadriceps were assessed based on muscle thickness and echo intensity, respectively. The changes in quadriceps thickness and echo intensity were calculated by subtracting these baseline values from these values at discharge. ADL were assessed at admission using the Barthel Index (BI). The participants were divided into the low BI (BI score <60) and high BI (BI score ≥60) groups in accordance with the BI score. Multiple regression analysis was performed to examine whether the change in quadriceps echo intensity was independently and significantly related to change in quadriceps thickness, even after adjusting for confounding factors in the total participants and high and low BI groups.
Results:
The number of the high and low BI groups were 54 and 144. Change in quadriceps echo intensity was independently and significantly related to changes in quadriceps thickness of the total participants (β = -0.53, p < 0.01) and low BI (β = - 0.51, p < 0.01) and high BI (β = -0.70, p < 0.01) groups.
Conclusions:
The results of this study indicate that there is a longitudinal negative relationship between muscle mass and intramuscular adipose tissue of the quadriceps in older inpatients regardless of ADL level. Intramuscular adipose tissue may be an important contributing factor for muscle mass.
COVID-19 is associated with musculoskeletal disorders. Ultrasound is a tool to assess muscle architecture and tendon measurements, offering an idea of the proportion of the consequences of the disease, since significant changes directly reflect the reduction in the ability to produce force and, consequently, in the functionality of the patient; however, its application in post-COVID-19 infection needs to be determined. We aimed to assess the intra- and inter-rater reliability of ultrasound measures of the architecture of the vastus lateralis (VL), rectus femoris (RF), vastus medialis (VM), gastrocnemius lateralis (GL), gastrocnemius medialis (GM), soleus (SO), and tibialis anterior (TA) muscles, as well as the patellar tendon (PT) cross-sectional area (CSA) in post-COVID-19 patients. An observational, prospective study with repeated measures was designed to evaluate 20 post-COVID-19 patients, who were measured for the pennation angle (θp), fascicular length (Lf), thickness, echogenicity of muscles, CSA and echogenicity of the PT. The intra-class correlation coefficient (ICC) and 95% limits of agreement were used. The intra-rater reliability presented high or very high correlations (ICC = 0.71–1.0) for most measures, except the θp of the TA, which was classified as moderate (ICC = 0.69). Observing the inter-rater reliability, all the evaluations of the PT, thickness and echogenicity of the muscles presented high or very high correlations. For the Lf, only the RF showed as low (ICC = 0.43), for the θp, RF (ICC = 0.68), GL (ICC = 0.70) and TA (ICC = 0.71) moderate and the SO (ICC = 0.40) low. The ultrasound reliability was acceptable for the muscle architecture, muscle and tendon echogenicity, and PT CSA, despite the low reliability for the Lf and θp of the RF and SO, respectively.
In this review we summarise the key techniques of muscle ultrasound as they apply to hereditary muscle disease. We review the diagnostic utility of muscle ultrasound including its role in guiding electromyography and muscle biopsy sampling. We summarize the different patterns of sonographic muscle involvement in the major categories of genetic muscle disorders and discuss the limitations of the technique. We hope to encourage others to adopt ultrasound in their care for patients with hereditary muscle diseases.
Background & Aims
A previous study indicated that an increase in muscle mass is related to a decrease in intramuscular adipose tissue in older peoples. However, the longitudinal relationship between muscle mass and intramuscular adipose tissue of stroke patients remains unclear. This study aimed to examine the longitudinal relationships between muscle mass and intramuscular adipose tissue of the quadriceps on the paretic and non-paretic sides in convalescent stroke patients.
Methods
This longitudinal study included 24 convalescent stroke patients. Ultrasound images were acquired at hospital admission and discharge using B-mode ultrasound imaging. Muscle mass and intramuscular adipose tissue of the quadriceps were evaluated with muscle thickness and echo intensity, respectively. Multiple regression analysis was performed to confirm whether changes in echo intensity of the quadriceps on the paretic and non-paretic sides were related to changes in muscle thickness of those. The age, sex, days from onset stroke, change in the subcutaneous fat thickness, and paretic lower extremity function were set as an independent variable.
Results
Change in echo intensity of the quadriceps on the paretic side (β = − 0.55, p = 0.018) was independently and significantly associated with changes in muscle thickness of the quadriceps on the paretic side. Similarly, change in echo intensity of the quadriceps on the non-paretic side (β = − 0.55, p = 0.013) was independently and significantly associated with change in muscle thickness of the quadriceps on the non-paretic side.
Conclusions
Our findings indicate that muscle mass and intramuscular adipose tissue of the quadriceps are strongly and negatively correlated and an increase in muscle mass of the quadriceps is related to a decrease in intramuscular adipose tissue on the paretic and non-paretic sides in convalescent stroke patients. Furthermore, we must recognize that convalescent stroke patients with a decrease in muscle mass have an increase in intramuscular adipose tissue.
Background & Aims
A recent cross-sectional study reported that a higher intramuscular adipose tissue of the quadriceps is related to higher malnutrition risk in older inpatients. However, a longitudinal relationship between them in older inpatients remains unclear. This study aimed to examine the relationship between the malnutrition risk at hospital admission and change in quadriceps intramuscular adipose tissue induced during the hospital stay in older inpatients.
Methods
The inclusion criteria in this longitudinal study were older patients (aged ≥ 65 years) who were referred to the department of rehabilitation. Patients who died during a hospital stay, who underwent thigh amputation, and who had a hospital stay of < 3 days or a lack of data were excluded from the study. Malnutrition risk at post-acute hospital admission was assessed using Geriatric Nutritional Risk Index (GNRI). Intramuscular adipose tissue and muscle mass of the quadriceps were assessed at hospital admission and discharge using echo intensity and muscle thickness on ultrasound images. The changes in quadriceps echo intensity and thickness were calculated by subtracting these baseline values from these values at discharge. Multiple regression analysis was performed to examine whether GNRI at admission is independently and significantly related to the quadriceps echo intensity and thickness at discharge and changes in quadriceps echo intensity and thickness. The independent variables were GNRI, age, sex, days from onset disease, disease, quadriceps echo intensity or thickness at admission, and change in quadriceps thickness.
Results
This study included 200 inpatients (median [interquartile range] age: 83.0 [77.0-88.0], 57.0% female). GNRI at admission was significantly and independently related to quadriceps echo intensity at discharge (β = -0.136, p = 0.008) and change in quadriceps echo intensity (β = -0.177, p = 0.008) In contrast, GNRI was not significantly and independently related to quadriceps thickness at discharge (β = 0.087, p = 0.158) and change in quadriceps thickness (β = 0.133, p = 0.158).
Conclusions
Our results suggest that a higher malnutrition risk at post-acute hospital admission in older inpatients is related to an increase of intramuscular adipose tissue of the quadriceps during the hospital stay. Malnutrition risk at hospital admission in older inpatients is considered to be a predictor for an increase of intramuscular adipose tissue of the quadriceps during a hospital stay.
The aim of this study was to investigate the potential application of computer‐aided analysis in the quantitative assessment of changes in skeletal muscle injury in the rabbit contusion model. Forty healthy rabbits were randomly divided into control (n = 5) and contusion (n = 35) groups. Rabbits in the contusion group were used to construct a muscle contusion model induced by a hammer hitting the right gastrocnemius, while the muscles of rabbits in the control group were non‐injured. Two‐dimensional ultrasound (2D US) and contrast‐enhanced ultrasonography (CEUS) were performed on the rabbits that had received skeletal muscle contusion injury at 1 h, and 1, 3, 7, 14, 21 and 28 days after injury. Afterwards, a multiscale blob feature (MBF) method was used to extract the textural features from the 2D US, and the muscle injuries were quantitatively evaluated. The eight textural parameters of skeletal muscle analysed by MBF at 1 h, and 1, 3 and 7 days post‐injury were found to be significantly higher in the contusion group than in the control group (p < .05). On Day 14, the textural parameters (e.g., greyscale mean [Mean], greyscale standard deviation [SDev], number of blobs, average size of blobs, homogeneity of distribution, periodicity of distribution [POD] and irregularity) were also evidently higher in the contusion group than in the control group (p < .05). On Day 28, Mean, SDev and POD in the contusion group were markedly higher (p < .05). After that, the microcirculation in the injured areas increased from Day 7 to Day 21 after injury, but decreased on Day 28 after injury. Thus the quantitative assessment of changes in skeletal muscle injury (SMI) using computer‐aided analysis allowed us to describe the geometric features of injured muscle fibres and the microperfusion changes estimated by the modified semi‐quantitative scoring system. This provides a scientific basis for the development of a novel approach for the evaluation of SMI and rehabilitation process.
Imaging is an important tool in the evaluation of idiopathic inflammatory myopathies. It plays a role in diagnosis, assessment of disease activity and follow-up, and as a non-invasive biomarker. Among the different modalities, nuclear magnetic resonance imaging (MRI), ultrasound (US), and positron emission tomography (PET) may have the most clinical utility in myositis. MRI is currently the best modality to evaluate skeletal muscle and provides excellent characterization of muscle edema and fat replacement through the use of T1-weighted and T2-weighted fat suppressed/STIR sequences. Although MRI can be read qualitatively for the presence of abnormalities, a more quantitative approach using Dixon sequences and the generation of water T2 parametric maps would be preferable for follow-up. Newer protocols such as diffusion-weighted imaging, functional imaging measures, and spectroscopy may be of interest to provide further insights into myositis. Despite the advantages of MRI, image acquisition is relatively time-consuming, expensive, and not accessible to all patients. The use of US to evaluate skeletal muscle in myositis is gaining interest, especially in chronic disease, where fat replacement and fibrosis are detected readily by this modality. Although easily deployed at the bedside, it is heavily dependent on operator experience to recognize disease states. Further, systematic characterization of muscle edema by US is still needed. PET provides valuable information on muscle function at a cellular level. Fluorodeoxyglucose (FDG-PET) has been the most common application in myositis to detect pathologic uptake indicative of inflammation. The use of neurodegenerative markers is now also being utilized for inclusion body myositis. These different modalities may prove to be complementary methods for myositis evaluation.
The authors evaluated the influence of perceptual and cognitive skills in mammography detection and interpretation by testing three groups representing different levels of mammography expertise in terms of experience, training, and talent with a mammography screening-diagnostic task.
One hundred fifty mammograms, composed of unilateral cranial-caudal and mediolateral oblique views, were displayed in pairs on a digital workstation to 19 radiology residents, three experienced mammographers, and nine mammography technologists. One-third of the mammograms showed malignant lesions; two-thirds were malignancy-free. Observers interacted with the display to indicate whether each image contained no malignant lesions or suspicious lesions indicating malignancy. Decision time was measured as the lesions were localized, classified, and rated for decision confidence.
Compared with performance of experts, alternative free response operating characteristic performance for residents was significantly lower and equivalent to that of technologists. Analysis of overall performance showed that, as level of expertise decreased, false-positive results exerted a greater effect on overall decision accuracy over the time course of image perception. This defines the decision speed-accuracy relationship that characterizes mammography expertise.
Differences in resident performance resulted primarily from lack of perceptual-learning experience during mammography training, which limited object recognition skills and made it difficult to determine differences between malignant lesions, benign lesions, and normal image perturbations. A proposed solution is systematic mentor-guided training that links image perception to feedback about the reasons underlying decision making.
In this pilot study the authors examined areas on a mammogram that attracted the visual attention of experienced mammographers and mammography fellows, as well as areas that were reported to contain a malignant lesion, and, based on their spatial frequency spectrum, they characterized these areas by the type of decision outcome that they yielded: true-positives (TP), false-positives (FP), true-negatives (TN), and false-negatives (FN). Five 2-view (craniocaudal and medial-lateral oblique) mammogram cases were examined by 8 experienced observers, and the eye position of the observers was tracked. The observers were asked to report the location and nature of any malignant lesions present in the case. The authors analyzed each area in which either the observer made a decision or in which the observer had prolonged (>1,000 ms) visual dwell using wavelet packets, and characterized these areas in terms of the energy contents of each spatial frequency band. It was shown that each decision outcome is characterized by a specific profile in the spatial frequency domain, and that these profiles are significantly different from one another. As a consequence of these differences, the profiles can be used to determine which type of decision a given observer will make when examining the area. Computer-assisted perception correctly predicted up to 64% of the TPs made by the observers, 77% of the FPs, and 70% of the TNs.
Computer-aided diagnosis (CAD) has become one of the major research subjects in medical imaging and diagnostic radiology. The basic concept of CAD is to provide a computer output as a second opinion to assist radiologists' image interpretation by improving the accuracy and consistency of radiological diagnosis and also by reducing the image reading time. In this article, a number of CAD schemes are presented, with emphasis on potential clinical applications. These schemes include: (1) detection and classification of lung nodules on digital chest radiographs; (2) detection of nodules in low dose CT; (3) distinction between benign and malignant nodules on high resolution CT; (4) usefulness of similar images for distinction between benign and malignant lesions; (5) quantitative analysis of diffuse lung diseases on high resolution CT; and (6) detection of intracranial aneurysms in magnetic resonance angiography. Because CAD can be applied to all imaging modalities, all body parts and all kinds of examinations, it is likely that CAD will have a major impact on medical imaging and diagnostic radiology in the 21st century.
BACKGROUND
Our purpose was to determine the diagnostic potential of a new, computerized method of interpreting transrectal ultrasound (TRUS) information by artificial neural network analysis (ANNA). This method was developed to resolve the current dilemma of visual differentiation between benign and malignant tissue on TRUS. To train and objectively evaluate ANNA, a new precise method of computerized virtual correlation of preoperative ultrasound findings and radical prostatectomy histopathology was devised. After training with this pathologically confirmed digitized TRUS information, ANNA was tested in a blinded study.
METHODS
Following radical prostatectomy, 289 pathology whole‐mount sections of 61 patients were correlated digitally with the corresponding TRUS slices. Specific selection of TRUS areas unequivocally identified on the correlated digitized pathohistology resulted in 553 pathology‐confirmed representations (samples). Of these, 53 were used for training and 500 were subjected to blind analysis by ANNA.
RESULTS
ANNA classified 378 (99%) of the 381 benign pathology‐confirmed samples correctly as benign. The false‐positive rate was 1% (n = 3). Of the 119 pathology‐confirmed malignant samples, 94 (79%) were classified correctly; 25 (21%) were falsely classified as normal. Out of all 119 cancers, ANNA classified 60 (71%) of the hypoechoic cancers as malignant and 24 (29%) as benign. Surprisingly, 34 (97%) of the isoechoic cancers were correctly classified by ANNA, missing only one sample.
CONCLUSIONS
The introduction of ANNA enhanced the accuracy of TRUS prostate cancer identification. Although not all malignant areas were detected, cancer was detected in each patient. The ability to detect isoechoic cancerous lesions appears to be the essential innovation over conventional TRUS interpretation. Prostate 39:198–204, 1999. © 1999 Wiley‐Liss, Inc.
Ultrasound imaging allows detection of pathologic change in muscle on the basis of increased strength of echoes. With current commercial equipment, however, there is no method of quantitation of the echoes representing muscle, and there is lack of uniformity in scanning methodology. We describe a specially constructed scanning system, designed to access the raw echo data directly from the ultrasound transducer, and allow display and measurement of the echo signals on a computer. In a study of 38 boys with Duchenne muscular dystrophy, aged 1 to 11 years, who had an ultrasound scan of the thigh muscle, 32 (84%) had abnormality on quantitation of the ultrasound echoes. The quantitative techniques we describe could easily be incorporated into the design of ultrasound scanners. (J Child Neurol 1989;4:S101-S106).
Ein aus zwei Komponenten bestehendes diagnostisches System einer bildgebenden und computerunterstützten Differenzierung unterschiedlicher neuromuskulärer Erkrankungen wird vorgestellt. Zunächst wird die Myosonographie mittels streng standardisierter Grauwerttechnik durchgeführt. Verglichen mit Histologie und Molekulargenetik können hierdurch mit einer Gesamttreffsicherheit von 63/72 (88 %) die Duchenne-Muskeldystrophie, spinale Muskelatrophie, hereditäre sensomotorische Neuropathie und Myositis sowie Muskelgesunde klassifiziert werden. Um den subjektiven Ultraschallbefund untersucherunabhängig zu objektivieren, wurde am gleichen Probandenkollektiv doppelblind das Verfahren der computergestützten Bild-Texturanalyse angewendet. Mit Hilfe der ermittelten Texturparameter, welche die Bildhelligkeit sowie vor allem die Mikro- und Makrostruktur der Geweberegion charakterisieren, war es möglich, mit einer Sensitivität von 77 bis 94 % und Spezifität von 81 bis 98 % gleichfalls eine zutreffende Klassifikation vorzunehmen. Beide Komponenten ergänzen sich somit zu einem qualitativ neuen diagnostischen System, das zusammen mit molekulargenetischen Methoden in ausgewählten Fällen die Histologie entbehrlich macht.
Computer-Supported Tissue Characterization in Ultrasound Images of Neuromuscular Diseases
A new diagnostic system combining conventional gray-scale ultrasonography (US) and computer-assisted texture analysis of sonograms makes it possible to differentiate more easily between specific neuromuscular diseases. The first step involves myosonography with strictly standardized US. In a group of 72 patients with histologically and molecular-genetically confirmed diagnosis 63 patients (88 %) were diagnosed by conventional US as having Duchenne's muscular dystrophy, spinal muscular atrophy, hereditary sensomotor neuropathy or inflammatory myopathy. Secondly, in a double blind setting computer-assisted texture analysis was used on the same sample of subjects. Tissue Texture can be characterized by the brightness as well as the micro- and macro-structure of the tissue. The use of these parameters leads to a sensitivity of 77 to 94 % and a specificity of 81 to 98 %. In conclusion, the combination of both techniques allows us to avoid invasive diagnostic procedures in a substantial group of patients.
This paper presents a general statistical methodology for the analysis of multivariate categorical data arising from observer reliability studies. The procedure essentially involves the construction of functions of the observed proportions which are directed at the extent to which the observers agree among themselves and the construction of test statistics for hypotheses involving these functions. Tests for interobserver bias are presented in terms of first-order marginal homogeneity and measures of interobserver agreement are developed as generalized kappa-type statistics. These procedures are illustrated with a clinical diagnosis example from the epidemiological literature.
Ultrasound imaging allows detection of pathologic change in muscle on the basis of increased strength of echoes. With current commercial equipment, however, there is no method of quantitation of the echoes representing muscle, and there is lack of uniformity in scanning methodology. We describe a specially constructed scanning system, designed to access the raw echo data directly from the ultrasound transducer, and allow display and measurement of the echo signals on a computer. In a study of 38 boys with Duchenne muscular dystrophy, aged 1 to 11 years, who had an ultrasound scan of the thigh muscle, 32 (84%) had abnormality on quantitation of the ultrasound echoes. The quantitative techniques we describe could easily be incorporated into the design of ultrasound scanners.
Ultrasonography of the thigh and calf was performed in 24 children who had primary neuromuscular disease and in 20 healthy children. The ultrasound image was clearly abnormal in all patients with progressive muscular dystrophy, and in the majority of children with benign myopathic disorders; the principal changes were increased muscular echogenicity and increased attenuation of ultrasound with a reduced bone surface echo. In 13 patients, the ultrasound findings were correlated with pathologic changes seen in muscle biopsy specimens: a clear correlation (r = .85) was found. Muscular dystrophies had a higher score of abnormal ultrasonographic and microscopic findings, while the more benign muscular diseases had a lower score.
A prospective study was done on 222 consecutive new patients referred to our pediatric muscle clinic to assess the diagnostic value of ultrasound imaging. Ultrasound scans were interpreted without knowledge of clinical presentation or results of other tests. Muscular dystrophy produced a brightly speckled pattern of increased echo from the muscle, whereas spinal muscular atrophy showed a moderate increase in muscle echo and associated muscle atrophy. Acute dermatomyositis produced a moderate increase in echo that varied markedly with the direction of the ultrasound beam in relation to the muscle fibres. The ultrasound scan was normal in children with hypotonia of cerebral origin, Prader Willi syndrome, ligamentous laxity, and other "nonneuromuscular" causes. In eight patients ultrasound scanning showed a striking degree of selective involvement of individual components of the quadriceps muscle, which provided considerable diagnostic help for selective needle biopsy. Ultrasound scanning in children has the major advantage of being a noninvasive and pleasant out-patient procedure, which can be readily done on multiple sites. It is a valuable screening test in the investigation of children with neuromuscular disorders.
The results of a study utilizing computerized real-time sonography (CRS) to image muscles in patients with neuromuscular disease are presented for 67 patients, 37 with neuromuscular disease and 4 with upper motor neuron disease, and 26 age-matched healthy controls between the ages of 2 days and 59 years. CRS is a safe, noninvasive, atraumatic method for evaluating a broad range of neuromuscular diseases. It is capable of differentiating myopathies or dystrophies from neurogenic atrophies and floppy infants with "central" hypotonia from those with neuromuscular diseases.
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.
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.
In skeletal muscle sonography high echogenicities have proved to be of diagnostic value. The following study examines whether these echointensities are caused mainly by interstitial fat or fibrosis. Consequently, the echogenicities of 86 muscles, their diameters, and the thickness of subcutaneous fat layers superficial to these muscles were measured and compared for content of fat and connective tissue, which were assessed by morphometry and biochemical testing in the corresponding muscle biopsy samples. The results indicate that fat replacement constitutes the main cause of increased muscle echogenicity, whereas intramuscular fibrosis did not significantly affect the muscles' echogenicity.
To evaluate the value of myosonography in inflammatory myopathies ultrasound of skeletal muscles was performed in 70 patients, aged 21-82 years, suffering from histologically proven polymyositis (n = 30), dermatomyositis (n = 18), granulomatous myositis (n = 9), inclusion body myositis (n = 13), and in 102 control persons. The sensitivity of muscle ultrasound in detecting histopathologically proven disease (82.9%) was not significantly different from electromyography (92.4%) or serum creatine kinase activity (68.7%). The positive predictive value of ultrasound was 95.1%, the negative predictive value 89.2%, and the accuracy 91.3%. The different types of inflammatory myopathies presented with typical, but not specific ultrasound features. Polymyositis showed atrophy and increased echointensity predominantly of lower extremity muscles, whereas in dermatomyositis clear muscle atrophy was rare and echointensities were highest in forearm muscles. Echointensities were lower in dermatomyositis compared to poly- and granulomatous myositis. Granulomatous myositis was characterized by the highest echointensities and a tendency towards muscle hypertrophy. Severe muscle atrophy was the most impressive feature in the majority of patients with inclusion body myositis. Comparison of ultrasound and histopathological findings indicates that muscle lipomatosis has a much greater impact on muscular echointensity than does muscle fibrosis. Ultrasound of myositis improved clinical assessment of patients by supplying differential diagnostic clues based on precise muscle size measurements and identification of mesenchymal abnormalities, particularly muscle lipomatosis.
Our purpose was to determine the diagnostic potential of a new, computerized method of interpreting transrectal ultrasound (TRUS) information by artificial neural network analysis (ANNA). This method was developed to resolve the current dilemma of visual differentiation between benign and malignant tissue on TRUS. To train and objectively evaluate ANNA, a new precise method of computerized virtual correlation of preoperative ultrasound findings and radical prostatectomy histopathology was devised. After training with this pathologically confirmed digitized TRUS information, ANNA was tested in a blinded study.
Following radical prostatectomy, 289 pathology whole-mount sections of 61 patients were correlated digitally with the corresponding TRUS slices. Specific selection of TRUS areas unequivocally identified on the correlated digitized pathohistology resulted in 553 pathology-confirmed representations (samples). Of these, 53 were used for training and 500 were subjected to blind analysis by ANNA.
ANNA classified 378 (99%) of the 381 benign pathology-confirmed samples correctly as benign. The false-positive rate was 1% (n = 3). Of the 119 pathology-confirmed malignant samples, 94 (79%) were classified correctly; 25 (21%) were falsely classified as normal. Out of all 119 cancers, ANNA classified 60 (71%) of the hypoechoic cancers as malignant and 24 (29%) as benign. Surprisingly, 34 (97%) of the isoechoic cancers were correctly classified by ANNA, missing only one sample.
The introduction of ANNA enhanced the accuracy of TRUS prostate cancer identification. Although not all malignant areas were detected, cancer was detected in each patient. The ability to detect isoechoic cancerous lesions appears to be the essential innovation over conventional TRUS interpretation.
One hundred paediatric, muscle ultrasound examinations performed in the evaluation of suspected neuromuscular disease were reviewed. The results were related to the presence or absence of neuromuscular disease in each child assessed. The group comprised 66 males and 34 females, age range 2 months to 16 years (mean 5.3 years). Scans were graded I-IV, according to muscle echogenicity, using Heckmatt's criteria. Thirty-two children had a final diagnosis of neuromuscular disease. The sensitivity of ultrasound in detecting neuromuscular disease was 78% with 91% specificity. The test was more reliable in the sub-group of > 3 years with a sensitivity of 81% and specificity of 96%. There was a significant difference in disease status, (with and without neuromuscular disease), between children with a normal, grade I, scan and those with an abnormal, grade II, III, IV, image (chi-square, P < 0.001, 95% confidence limits 0.54-0.86). Muscle ultrasound is a specific and sensitive investigation for suspected neuromuscular disease in children.
The aim of this study was to assess the diagnostic value of muscle ultrasonography in focal neuropathies.
100 patients suffering from unilateral symptoms or signs on the extremities indicating injuries of nerve roots, plexus, or peripheral nerves were prospectively examined by manual muscle testing (MMT), electromyography (EMG), and quantitative muscle ultrasonography. Muscle thickness and echointensity (gray scale analysis) were measured and compared to the results from 28 control subjects.
Ultrasonography was as sensitive as MMT and EMG in detecting muscle involvement. Ultrasonography and EMG were complementary. In 27% of 85 paretic muscles, only one of both techniques revealed pathological findings. Increased echointensity was seen in 82%, atrophy in 31% of pathological muscles. Earliest ultrasonographic abnormalities and pathological spontaneous activity in EMG appeared 10 days after the injury. The inter-observer agreement of ultrasonography was slightly, but significantly lower than that of EMG.
Muscle ultrasound can visualize anatomical abnormalities such as muscle atrophy and mesenchymal abnormalities in lesions of nerve roots, plexus, and peripheral nerve lesions.
As a result of the enhanced clinical application of prostate specific antigen (PSA), an increasing number of men are becoming candidates for prostate cancer work-up. A high PSA value over 20 ng/ml is a good indicator of the presence of prostate cancer, but within the range of 4-10 ng/ml, it is rather unreliable. Even more alarming is the fact that prostate cancer has been found in 12-37% of patients with a "normal" PSA value of under 4 ng/ml (Hybritech). While PSA is capable of indicating a statistical risk of prostate cancer in a defined patient population, it is not able to localize cancer within the prostate gland or guide a biopsy needle to a suspicious area. This necessitates an additional effective diagnostic technique that is able to localize or rule out a malignant growth within the prostate. The methods available for the detection of these prostate cancers are digital rectal examination (DRE) and Transrectal ultrasound (TRUS). DRE is not suitable for early detection, as about 70% of the palpable malignancies have already spread beyond the prostate. The classic problem of visual interpretation of TRUS images is that hypoechoic areas suspicious for cancer may be either normal or cancerous histologically. Moreover, about 25% of all cancers have been found to be isoechoic and therefore not distinguishable from normal-appearing areas. None of the current biopsy or imaging techniques are able to cope with this dilemma. Artificial neural networks (ANN) are complex nonlinear computational models, designed much like the neuronal organization of a brain. These networks are able to model complicated biologic relationships without making assumptions based on conventional statistical distributions. Applications in Medicine and Urology have been promising. One example of such an application will be discussed in detail: A new method of Artificial Neural Network Analysis (ANNA) was employed in an attempt to obtain existing subvisual information, other than the gray scale, from conventional TRUS and to improve the accuracy of prostate cancer identification.
A new diagnostic system combining conventional gray-scale ultrasonography (US) and computer-assisted texture analysis of sonograms makes it possible to differentiate more easily between specific neuromuscular diseases. The first step involves myosonography with strictly standardized US. In a group of 72 patients with histologically and molecular-genetically confirmed diagnosis 63 patients (88%) were diagnosed by conventional US as having Duchenne's muscular dystrophy, spinal muscular atrophy, hereditary sensomotor neuropathy or inflammatory myopathy. Secondly, in a double blind setting computer-assisted texture analysis was used on the same sample of subjects. Tissue Texture can be characterized by the brightness as well as the micro- and macro-structure of the tissue. The use of these parameters leads to a sensitivity of 77 to 94% and a specificity of 81 to 98%. In conclusion, the combination of both techniques allows us to avoid invasive diagnostic procedures in a substantial group of patients.
Floppiness in an infant may have a number of different etiologies from disorders of the brain to spinal cord lesions, neuropathies, neuromuscular junction disorders and myopathies. In this study we aimed to investigate the correlation of muscle ultrasonography (US) and electromyography (EMG) in the diagnosis of floppy infants. The study encompassed 41 floppy infants aged 2-24 months. The muscle US and EMG examinations were performed without awareness of the clinical diagnosis. The final diagnosis was established by molecular genetic tests or muscle/nerve biopsy. The neurogenic group consisted of 16 infants according to their US and EMG findings. Fifteen of them had spinal muscular atrophy proven by genetic analysis and one had polyneuropathy diagnosed by nerve biopsy. Six infants were in the myopathic group according to their muscle US and EMG results. All of them underwent muscle biopsy and microscopic examination revealed five congenital muscular dystrophy and one glycogen storage disease. In two infants the US and EMG data conflicted. Their biopsies were also insufficient for the diagnosis. Seventeen infants had normal US and EMG findings but pathologic cranial magnetic resonance imaging or metabolic/genetic tests. They were considered in the group of central hypotonia. Our results suggest a high concordance of US and EMG findings in the diagnostic work-up of neurogenic and myopathic disorders.
To develop a computer-aided diagnosis (CAD) algorithm with setting-independent features and artificial neural networks to differentiate benign from malignant breast lesions.
Two sets of breast sonograms were evaluated. The first set contained 160 lesions and was stored directly on the magnetic optic disks from the ultrasonographic (US) system. Four different boundaries were delineated by four persons for each lesion in the first set. The second set comprised 111 lesions that were extracted from the hard-copy images. Seven morphologic features were used, five of which were newly developed. A multilayer feed-forward neural network was used as the classifier. Reliability, extendability, and robustness of the proposed CAD algorithm were evaluated. Results with the proposed algorithm were compared with those with two previous CAD algorithms. All performance comparisons were based on paired-samples t tests.
The area under the receiver operating characteristic curve (A(z)) was 0.952 +/- 0.014 for the first set, 0.982 +/- 0.004 for the first set as the training set and the second set as the prediction set, 0.954 +/- 0.016 for the second set as the training set and the first set as the prediction set, and 0.950 +/- 0.005 for all 271 lesions. At the 5% significance level, the performance of the proposed CAD algorithm was shown to be extendible from one set of US images to the other set and robust for both small and large sample sizes. Moreover, the proposed CAD algorithm was shown to outperform the two previous CAD algorithms in terms of the A(z) value.
The proposed CAD algorithm could effectively and reliably differentiate benign and malignant lesions. The proposed morphologic features were nearly setting independent and could tolerate reasonable variation in boundary delineation.
To provide further insight into the MRI assessment of age-related white matter changes (ARWMCs) with visual rating scales, 3 raters with different levels of experience tested the interrater agreement and comparability of 3 widely used rating scales in a cross-sectional and follow-up setting. Furthermore, the correlation between visual ratings and quantitative volumetric measurement was assessed.
Three raters from different sites using 3 established rating scales (Manolio, Fazekas and Schmidt, Scheltens) evaluated 74 baseline and follow-up scans from 5 European centers. One investigator also rated baseline scans in a set of 255 participants of the Austrian Stroke Prevention Study (ASPS) and measured the volume of ARWMCs.
The interrater agreement for the baseline investigation was fair to good for all scales (kappa values, 0.59 to 0.78). On the follow-up scans, all 3 raters depicted significant ARWMC progression; however, the direct interrater agreement for this task was poor (kappa, 0.19 to 0.39). Comparison of the interrater reliability between the 3 scales revealed a statistical significant difference between the scale of Manolio and that of Fazekas and Schmidt for the baseline investigation (z value, -2.9676; P=0.003), demonstrating better interrater agreement for the Fazekas and Schmidt scale. The rating results obtained with all 3 scales were highly correlated with each other (Spearman rank correlation, 0.712 to 0.806; P< or =0.01), and there was significant agreement between all 3 visual rating scales and the quantitative volumetric measurement of ARWMC (Kendall W, 0.37, 0.48, and 0.57; P<0.001).
Our data demonstrate that the 3 rating scales studied reflect the actual volume of ARWMCs well. The 2 scales that provide more detailed information on ARWMCs seemed preferential compared with the 1 that yields more global information. The visual assessment of ARWMC progression remains problematic and may require modifications or extensions of existing rating scales.
In this study, 145 healthy adults (20 to 94 years old, 69 women) were examined using ultrasound (US) imaging to obtain reference values of muscle parameters that were previously not available. We measured biceps and quadriceps sizes and subcutaneous fat thickness. To quantify muscle aspect, we defined and calculated the muscle aspect parameters muscle density, inhomogeneity and white-area index by digital image analysis. All muscle aspect parameters were found to increase with age, which may be due to age-related muscle replacement by fatty tissue and collagen. Other age-, weight- and gender-dependencies are also discussed. The complete set of muscle parameters was used to differentiate between typical myopathies and neuropathies in a group of 32 patients (24 to 79 years old, 18 women). We were successful in almost completely separating the two types of disorders based on abnormality of muscle aspect parameters alone. These preliminary results show that this set of normal muscle parameters can be used to help diagnose neuromuscular disorders. It will also facilitate follow-up in disease progression and therapy.
We determined prospectively the diagnostic value of quantitative ultrasonography in detecting neuromuscular disorders in children. Ultrasonographic scans of four muscles were made in 36 children with symptoms or signs suggestive of neuromuscular disease, such as muscle weakness and hypotonia. The muscle thickness, ratio of muscle thickness to subcutaneous fat thickness, and echo intensity were determined in each muscle. The echo intensity was measured using computer-assisted gray-scale analysis. Thirteen of the 36 patients had a neuromuscular disorder (6 a myopathy and 7 a neuropathy). Differentiation between neuromuscular diseases and nonneuromuscular diseases could be made on the basis of echo intensities with a sensitivity of 92%, a specificity of 90%, a positive predictive value of 86%, and a negative predictive value of 95%. We conclude that computer-assisted quantitative analysis of muscle echo intensity is a reliable method to discriminate between neuromuscular and nonneuromuscular diseases in children.
The purpose of this study was to establish normal values of muscle thickness, ratio of muscle thickness to subcutaneous fat thickness, and muscle echo intensity in children between 11 weeks and 16 years of age. Transverse scans of four muscles were made by standardized real-time ultrasound examination. The scans were digitized, and mean echo intensity was measured using gray-scale analysis. A multiple regression equation was used to study which independent parameter (age, height, weight, or sex) influenced the variables for each muscle. Muscle thickness depended on the child's weight. The other parameters did not significantly influence muscle thickness after correction for weight. The ratio of muscle thickness to subcutaneous fat thickness depended on age. Echo intensity showed no correlation with either of the variables. As a result, all normal values, including the equation to calculate them, are described. These normal data may help to determine the diagnostic value of muscle ultrasound in children with suspected neuromuscular disease.
The study of Helvie et al demonstrates that there are approaches to computer-aided detection development and implementation, other than those that have been commercialized and approved by the Food and Drug Administration, that can be used to achieve performance that is at least as good as that achieved with commercial systems.
In this study, 105 healthy children (45 to 156 months old, 57 girls) were examined using ultrasound (US) imaging to obtain reference values of muscle dimensional and aspect parameters. We measured biceps and quadriceps sizes and subcutaneous tissue thickness. To quantify muscle aspect, we calculated muscle density, inhomogeneity and white-area index by digital image analysis. Age-, weight- and gender-dependencies were discussed. We demonstrated earlier that the complete set of parameters allows for differentiation between myopathies and neuropathies in adults, with high sensitivity. In this study, we investigated if these parameters have additional value in the diagnostic evaluation of 36 children with proven neuromuscular disease (20 Duchenne muscular dystrophy, 16 neuropathies). We found that density analysis provides a sensitive method for distinguishing between healthy children and children with neuromuscular disorders. We have also found that more detailed aspect analysis is necessary to further distinguish between these types of neuromuscular disorders in children. In conclusion, this set of normal muscle parameters can be used to help diagnose neuromuscular disorders in children. It will also facilitate follow-up in disease progression and therapy.
Clinical epidemiology; the architecture of clinical re-search. Philadelphia: W.B. Sauders Company Muscle imaging in neuromuscular disease using computerized real-time sonography
- Feinstein Ar Fischer Aq
- Carpenter Dw
- Hartlage
- Carroll Je Pl
- Stephens
Feinstein AR. Clinical epidemiology; the architecture of clinical re-search. Philadelphia: W.B. Sauders Company, 1985. Fischer AQ, Carpenter DW, Hartlage PL, Carroll JE, Stephens S. Muscle imaging in neuromuscular disease using computerized real-time sonography. Muscle Nerve 1988;11:270 –275.