Skeletal muscle sonography: a correlative study of echogenicity and morphology

Relationship of serial muscle ultrasound of rectus femoris and ambulatory recovery in patients with acute incomplete spinal cord injury: A prospective observational study

CONTEXT/OBJECTIVE

To investigate the change in serial muscle ultrasound of rectus femoris of patients with incomplete spinal cord injury (SCI) performed within 2 months after SCI during acute rehabilitation, and the relationship with functional outcomes at 1 year post-injury.

DESIGN

Prospective observational study.

SETTING

Inpatient multi-speciality tertiary rehabilitation center in Singapore.

PARTICIPANTS

Fifty-four patients with incomplete SCI, defined as American Spinal Injury Association Impairment Scale B-D, with SCI above L2, were recruited from March 2020 to June 2021. Serial muscle ultrasound of the rectus femoris thickness and echo intensity were obtained at 1 week post-injury and after 2 months via standardized protocols.

OUTCOME MEASURES

Functional Independence Measure (FIM) motor score, Lower Extremity Motor Score (LEMS), Spinal Cord Independence Measure III (SCIM III) indoor mobility component and Walking Index for Spinal Cord Injury II (WISCI II) were assessed in the first week post-admission and at 1 year.

RESULTS

There was a significant positive correlation between change in rectus femoris muscle thickness over 2 months and FIM motor score (P < 0.001), LEMS (P < 0.001), SCIM III indoor mobility component (P < 0.001) and WISCI II (P < 0.001) at 1 year. For the change in echo intensity over 2 months, there was a significantly negative correlation with FIM motor score (P = 0.002), LEMS (P = 0.002), SCIM III indoor mobility component (P = 0.001) and WISCI II (P = 0.001) at 1 year.

CONCLUSION

The findings suggest that ultrasonographic serial assessment of rectus femoris muscle thickness and echo intensity during rehabilitation may be useful for determining the long-term functional outcomes in patients with incomplete SCI.

Muscle oxidative capacity but not specific force is greater in aerobic versus resistance trained young adults

PURPOSE

Near-infrared spectroscopy (NIRS) can be applied to assess skeletal muscle oxidative capacity ( m V ˙ O 2 ). Specific force (SF) and echo intensity (EI) represent muscle quality. However, it is unknown how exercise participation and biological sex impact m V ˙ O 2 , and if measures of muscle quality are related to m V ˙ O 2 . The aim was to assess training history- and biological sex-related differences in m V ˙ O 2 , SF, and EI in males and females.

METHODS

To determine training history, 50 adults (23 females, 66% resistance trained, age:22 ± 3 years) completed strength and cardiorespiratory fitness assessments. Ultrasonography assessed muscle cross-sectional area (mCSA) and EI of the dominant vastus lateralis. The ratio of maximal strength to mCSA was defined as SF. To assess m V ˙ O 2 , participants cycled for 5 min at 50% of their peak power observed at maximal oxygen consumption. Following this, a mono-exponential decay curve, deriving the rate constant (k), was created from post-exercise NIRS recovery slopes. Separate 2(Sex) × 2(Training History) ANOVAs examined differences in k, SF, and EI. Pearson's correlation coefficients evaluated relations among k, SF, and EI.

RESULTS

There was a significant interaction for k (p = 0.025,η p 2 = 0.105 ), such that k was greater in aerobically trained adults. Additionally, SF was significantly greater for resistance trained individuals (p < 0.001), whereas EI was not different between training history groups (p = 0.363). For the resistance trained group, SF and m V ˙ O 2 were related (r = - 0.455, p = 0.002). EI was associated with m V ˙ O 2 (r = 0.465, p = 0.006).

CONCLUSION

Chronic aerobic exercise promotes faster recovery following exercise bouts, whereas resistance training yields superior muscle quality, possibly demonstrating the consequences of a physiological trade-off and/or training-specificity.

Thigh muscle features in female patients with severe knee osteoarthritis: a cross-sectional study

BACKGROUND

Muscle function deterioration in female patients with severe knee osteoarthritis (KOA) is linked to alterations in muscle morphology, composition, and mechanical properties. This study evaluates thigh muscle features in female patients with severe KOA and explores correlations with knee joint function.

METHODS

Ultrasound and shear wave elastography measured physiological cross-sectional area (PCSA), echo intensity (EI), and shear modulus (G) in the rectus femoris (RF), vastus lateralis (VL), vastus medialis (VM), biceps femoris long head (BFL), and semitendinosus (ST) of 24 KOA patients and 24 controls. EI indicates intramuscular fat, while G reflects stiffness. Muscle characteristics were compared between groups, and correlations with knee function scores (WOMAC, KSS, HSS) were analyzed.

RESULTS

In patients, the symptomatic side displayed reduced PCSA for RF, VL, VM, BFL, and ST (15.85[Formula: see text], 28.18[Formula: see text], 21.53[Formula: see text], 11.67[Formula: see text], 6.59[Formula: see text] respectively) vs. controls (19[Formula: see text], 36.32[Formula: see text], 23.37[Formula: see text], 14.15[Formula: see text], 7.12[Formula: see text] respectively). EI was elevated (128.95, 121.12, 105.72, 90.52, 93.15) vs. controls (100.39, 93.97, 88.14, 77.69, 78.73), and G values (9.48 kPa, 7.88 kPa, 6.9 kPa, 7.2 kPa, 9.03 kPa) was higher than controls (8.85 kPa, 5.28 kPa, 5.98 kPa, 6.58 kPa, 6.73 kPa). BFL`s G, ST`s G, and VM`s EI, negatively correlated with knee function, whereas BFL`s PCSA positively correlated. The variable importance of BFL's PCSA and G ranked at the top in all scores.

CONCLUSIONS

Compared to controls, PCSAs in muscles on both sides of KOA patients were lowered by up to 22%, indicative of muscle loss and diminished strength. The G value is 20.65% higher, suggesting poor flexibility and elevated passive tension. EI in muscles on both sides of KOA patients was greater, reaching up to 23.88%, possibly reducing contractile components and muscle force. G, PCSA, and EI are closely correlated with function scores, and PCSA and G of BFL are the most significant predictors of knee function. These results may help explain muscle dysfunction in KOA patients.

CLINICAL TRIAL NUMBER

Not applicable.

Rectus Femoris Muscle Segmentation on Ultrasound Images of Older Adults Using Automatic Segment Anything Model, nnU-Net and U-Net-A Prospective Study of Hong Kong Community Cohort

Sarcopenia is characterized by a degeneration of muscle mass and strength that incurs impaired mobility, posing grievous impacts on the quality of life and well-being of older adults worldwide. In 2018, a new international consensus was formulated to incorporate ultrasound imaging of the rectus femoris (RF) muscle for early sarcopenia assessment. Nonetheless, current clinical RF muscle identification and delineation procedures are manual, subjective, inaccurate, and challenging. Thus, developing an effective AI-empowered RF segmentation model to streamline downstream sarcopenia assessment is highly desirable. Yet, this area of research readily goes unnoticed compared to other disciplines, and relevant research is desperately wanted, especially in comparison among traditional, classic, and cutting-edge segmentation networks. This study evaluated an emerging Automatic Segment Anything Model (AutoSAM) compared to the U-Net and nnU-Net models for RF segmentation on ultrasound images. We prospectively analyzed ultrasound images of 257 older adults (aged > 65) in a community setting from Hong Kong's District Elderly Community Centers. Three models were developed on a training set (n = 219) and independently evaluated on a testing set (n = 38) in aspects of DICE, Intersection-over-Union, Hausdorff Distance (HD), accuracy, precision, recall, as well as stability. The results indicated that the AutoSAM achieved the best segmentation agreement in all the evaluating metrics, consistently outperforming the U-Net and nnU-Net models. The results offered an effective state-of-the-art RF muscle segmentation tool for sarcopenia assessment in the future.

Determinants of Maximal Dorsiflexion Range of Motion: Multi-Perspective Comparison Using Mechanical, Neural, Morphological, and Muscle Quality Factors

Background/Objectives: the purpose of this study was to determine the contributions of mechanical, neural, morphological, and muscle quality factors on individual differences in the maximal ankle dorsiflexion range of motion (ROM). Methods: A sample of 41 university students performed passive-dorsiflexion and morphological measurements. In the passive-dorsiflexion measurement, while the ankle was passively dorsiflexed, maximal dorsiflexion ROM was measured in addition to passive torque at a given angle and muscle-tendon junction (MTJ) displacement during the last 13° as mechanical factors, and stretch tolerance and muscle activation were measured as neural factors. In morphological measurements, the cross-sectional area, muscle thickness, muscle fascicle length, and pennation angle were measured. In addition, the echo intensity was evaluated as muscle quality. Subjects were divided into three groups (flexible, moderate, and tight) using the value of the maximal dorsiflexion ROM. Results: Maximal dorsiflexion ROM and stretch tolerance were greater in the flexible group than those in the moderate and tight groups. MTJ displacement was smaller in the flexible group than those in the moderate and tight groups. Stepwise multiple regression analysis revealed that stretch tolerance and passive torque at a given angle were selected as parameters to explain the maximal dorsiflexion ROM (adjusted R2 = 0.83). Conclusions: these results indicate that individual differences in maximal ankle dorsiflexion ROM are primarily related to mechanical and neural factors.

Muscle Pathology Associated With Cardiac Function in Duchenne Muscular Dystrophy

OBJECTIVE

To compare the progression of muscle fibrosis of various site and its relation between cardiac deterioration in Duchenne muscular dystrophy (DMD). In this study aimed to examine the associations between echocardiogram-based cardiac function indices and fibrosis of the abdominal and lower extremity muscles in patients with DMD to facilitate early detection of cardiac dysfunction and identify its predictors.

METHODS

Twenty-one patients with DMD patients were enrolled in the study. The association between cardiac dysfunction and fibrosis of the abdominal and lower extremity muscles was determined by analyzing the echocardiography and elastography. Non-parametric Spearman rank correlation coefficients were used to examine the pairwise relationships between cardiac function and muscle elasticity.

RESULTS

All patients were male and non-ambulant. Their mean age was 18.45±4.28 years. The strain ratios of the abdominal muscle and quadriceps muscles were significantly higher than those of the medial gastrocnemius. The strain ratio of the rectus abdominis muscle has a significant negative correlation with left ventricular ejection fraction. Cardiac function and valvular insufficiency were not significantly correlated with muscle strain ratio. According to the result of our study, the only skeletal muscle which showed significant correlation with cardiac dysfunction was degree abdominal muscle fibrosis.

CONCLUSION

The degree of fibrosis of respiratory muscles was also significantly associated with cardiac dysfunction; therefore, it can be used as a predictor of cardiac dysfunction in patients with DMD in clinical practice.

Influence of Change in Echo Intensity of the Pretalar Fat Pad in Young Individuals With Chronic Ankle Instability

This study aimed to investigate the echo intensity (EI) of the pretalar fat pad (PFP) in young individuals with chronic ankle instability (CAI) and clarify the relationship between changes in the PFP and the clinical characteristics of CAI. Using the Identification of Functional Ankle Instability (IdFAI) scores, 26 limbs of 15 participants were divided into CAI (IdFAI score ≥11, male: eight limbs, female: six limbs, age: 21±1 years) and normal (IdFAI score <11, male: nine limbs, female: three limbs, age: 20±1 years) groups. The EI of the PFP was measured, and the luminosity ratio (LR) to the EI of the subcutaneous adipose tissue was calculated. To evaluate ankle joint stability and function, the fibulo-talar separation rate and weight-bearing lunge test (WBLT) values were measured. These parameters were compared between the two groups, and their correlations were statistically analyzed. The median IdFAI score in the CAI group was 15.5. The LR of the PFP was significantly higher in the CAI group than in the normal group (P<0.01). The fibulo-talar separation rate values were significantly higher (P=0.006), and the WBLT values were lower (P=0.011) in the CAI group. A moderate negative correlation was observed between the LR and WBLT values (r =-0.44, P=0.03). The LR of the PFP was high in the CAI group and was related to limited dorsiflexion of the ankle joint in the loaded position. Evaluating the entire ankle joint, including the PFP, is important, even for young individuals with mild CAI.

A Novel Exercise to Improve Suprahyoid Muscle Area and Intensity as Evaluated by Ultrasonography

Insufficient suprahyoid muscle strength with poor opening of the upper esophageal sphincter can cause dysphagia. This study investigated whether an exercise of the suprahyoid muscle, named forehead exercise for suprahyoid muscles (FESM, "Enge-Odeko-Taiso" in Japanese), improves the geniohyoid muscle area and intensity using ultrasonography. Sixty-four participants (15 men and 49 women, 82.8 ± 6.0 years) living independently with no symptoms of swallowing difficulties were enrolled. The participants were divided into the FESM and the control group. The FESM is an isometric exercise involving repetitions of looking into the navel as if the chin is pulled back with little neck motion using a hand pushed against the forehead for resistance. This exercise is performed five times in 10 courses a day (total 50 times) for 8 weeks. Participants in the control group did not conduct any exercises. Body mass index, hand grip strength, gait speed, calf circumference, Mini Nutritional Assessment short-form, eating assessment tool, repetitive saliva swallowing test (RSST), and Food Intake LEVEL Scale scores were examined. The ultrasonographic geniohyoid muscle area, intensity, and RSST were investigated before and after the program. In the FESM group, the geniohyoid muscle area increased from 2.24 to 2.52 cm2 (P < 0.05), intensity decreased from 34.6 to 32.0 (P < 0.05), and the median RSST increased from 5 to 6 (P < 0.05) significantly. Conversely, no significant differences were observed in the control group. The FESM was effective to increase the area and decrease the intensity of the geniohyoid muscle and may improve swallowing function.

Association between quadriceps muscle thickness or echo intensity, malnutrition, and activities of daily living in an integrated medical and long-term care facility: A cross-sectional study

BACKGROUND &AIMS

Malnutrition and physical function impairment are prevalent concerns in long-term care facilities. This study investigated the relationship between quadriceps muscle thickness (QMT) or echo intensity (QEI), nutritional status, and activities of daily living (ADL) in residents of an Integrated Facility for Medical and Long-term Care (IFMLC) in Japan.

METHODS

Using a cross-sectional design, 126 residents (86 women, median age 89 years) at an IFMLC were assessed. Malnutrition was diagnosed using the Global Leadership Initiative on Malnutrition (GLIM) criteria including disease burden/inflammation, while ADL status was evaluated using the Barthel Index (BI). QMT and QEI, indicative of muscle mass and intramuscular adipose tissue, were measured by ultrasound. Multivariate logistic and linear regression analyses were conducted to explore the association of QMT or QEI with malnutrition and ADL.

RESULTS

62 residents (49%) were in the lower QMT group and 63 residents (50%) were in the upper QEI group. The prevalence of severe malnutrition in the lower QMT group was significantly higher than that in the upper QMT group. Moreover, the lower QMT group had significantly lower BI points than the upper QMT group. The upper QEI group had significantly lower BI points than the lower QEI group. lower QMT was associated with severe malnutrition (odds ratio 3.170; 95% CI 1.238 to 8.725; P = 0.016). Furthermore, both lower QMT (B = -12.520; 95% CI -17.069 to -7.973; P < 0.001) and upper QEI (B = -7.598; 95% CI -12.565 to -2.631; P = 0.003) showed an independent correlation with lower BI scores.

CONCLUSION

This study found a relationship between lower QMT correlated with severe malnutrition and poor ADL, while higher QEI is associated with poor ADL.

Establishment and Validation of a Predictive Model for Sarcopenia Based on 2-D Ultrasound and Shear Wave Elastography in the Medial Gastrocnemius Muscle

OBJECTIVE

To develop and validate a predictive model for sarcopenia.

METHODS

A total of 240 subjects who visited our hospital between August 2021 and May 2023 were randomly divided by time of entry into a training set containing 2/3 of patients and a validation set containing 1/3 of patients. The muscle thickness (MT), echo intensity (EI), and shear wave velocity (SWV) of the medial gastrocnemius muscle were measured. Indicators that were meaningful in the univariate analysis in the training set were included in a binary logistic regression to derive a regression model, and the model was evaluated using a consistency index, calibration plot, and clinical validity curve. Diagnostic efficacy and clinical applicability were compared between the model and unifactorial indicators.

RESULTS

Four meaningful variables, age, body mass index (BMI), MT, and SWV, were screened into the predictive model. The model was Logit Y = 21.292 + 0.065 × Age - 0.411 × BMI - 0.524 × MT - 3.072 × SWV. The model was well differentiated with an internally validated C-index of 0.924 and an external validation C-index of 0.914. The calibration plot predicted probabilities against actual probabilities showed excellent agreement. The specificity, sensitivity, and Youden's index of the model were 73.80%, 97.40%, and 71.20%, respectively, when using the diagnostic cut-off value of >0.279 for sarcopenia. The logistic model had higher diagnostic efficacy (p < 0.001) and higher net clinical benefit (p < 0.001) over the same threshold range compared to indicators.

CONCLUSION

The logistic model of sarcopenia has been justified to have good discriminatory, calibrated, and clinical validity, and has higher diagnostic value than indicators.

Muscle Quality as a Potential Diagnostic Marker of Advanced Liver Fibrosis in Patients with Non-alcoholic Fatty Liver Disease

Background

Muscle-liver crosstalk plays an important role in the development and progression of non-alcoholic fatty liver disease (NAFLD). The measurement of muscle echo-intensity during ultrasonography is a real-time, non-invasive method of assessing muscle quality. In this retrospective study, we investigated the significance of poor muscle quality (namely, a greater mass of non-contractile tissue, including intramuscular fat) as a risk factor for advanced liver fibrosis and considered whether it may represent a useful tool for the diagnosis of advanced liver fibrosis.

Methods

We analyzed data from 307 patients with NAFLD (143 men and 164 women) who visited the University of Tsukuba Hospital between 2017 and 2022. The patients were stratified into the following tertiles of muscle quality according to their muscle echo-intensity on ultrasonography: modest (84.1 arbitrary units [A.U.]), intermediate (97.4 A.U.), and poor (113.6 A.U.). We then investigated the relationships between muscle quality and risk factors for advanced liver fibrosis and calculated appropriate cutoff values.

Results

Patients with poor muscle quality showed a significant, 7.6-fold greater risk of liver fibrosis compared to those with modest muscle quality. Receiver operating characteristic curve analysis showed that muscle quality assessment was as accurate as the fibrosis-4 index and NAFLD fibrosis score in screening for liver fibrosis and superior to the assessment of muscle quantity and strength, respectively. Importantly, a muscle echo-intensity of ≥92.4 A.U. may represent a useful marker of advanced liver fibrosis.

Conclusion

Muscle quality may represent a useful means of identifying advanced liver fibrosis, and its assessment may become a useful screening tool in daily practice.

Contractile properties and magnetic resonance imaging-assessed fat replacement of muscles in myotonia congenita

BACKGROUND AND PURPOSE

Myotonia congenita (MC) is a muscle channelopathy in which pathogenic variants in a key sarcolemmal chloride channel Gene (CLCN1) cause myotonia. This study used muscle magnetic resonance imaging (MRI) to quantify contractile properties and fat replacement of muscles in a Danish cohort of MC patients.

METHODS

Individuals with the Thomsen (dominant) and Becker (recessive) variants of MC were studied. Isometric muscle strength, whole-body MRI, and clinical data were collected. The degree of muscle fat replacement of thigh, calf, and forearm muscles was quantitively calculated on Dixon MRI as fat fractions (FFs). Contractility was evaluated as the muscle strength per contractile muscle cross-sectional area (PT/CCSA). Muscle contractility was compared with clinical data.

RESULTS

Intramuscular FF was increased and contractility reduced in calf and in forearm muscles compared with controls (FF = 7.0-14.3% vs. 5.3-9.6%, PT/CCSA = 1.1-4.9 Nm/cm2 vs. 1.9-5.8 Nm/cm2 [p < 0.05]). Becker individuals also showed increased intramuscular FF and reduced contractility of thigh muscles (FF = 11.9% vs. 9.2%, PT/CCSA = 1.9 Nm/cm2 vs. 3.2 Nm/cm2 [p < 0.05]). Individual muscle analysis showed that increased FF was limited to seven of 18 examined muscles (p < 0.05). There was a weak correlation between reduced contractility and severity of symptoms.

CONCLUSIONS

Individuals with MC have increased fat replacement and reduced contractile properties of muscles. Nonetheless, changes were small and likely did not impact clinically on their myotonic symptoms.

Skeletal Muscle Compliance and Echogenicity in Resistance-Trained and Nontrained Women

ABSTRACT

Mongold, SJ, Ricci, AW, Hahn, ME, and Callahan, DM. Skeletal muscle compliance and echogenicity in resistance-trained and nontrained women. J Strength Cond Res 38(4): 671-680, 2024-Noninvasive assessment of muscle mechanical properties in clinical and performance settings tends to rely on manual palpation and emphasizes examination of musculotendinous stiffness. However, measurement standards are highly subjective. The purpose of the study was to compare musculotendinous stiffness in adult women with varying resistance training history while exploring the use of multiple tissue compliance measures. We identified relationships between tissue stiffness and morphology, and tested the hypothesis that combining objective measures of morphology and stiffness would better predict indices of contractile performance. Resistance-trained (RT) women (n = 11) and nontrained (NT) women (n = 10) participated in the study. Muscle echogenicity and morphology were measured using B-mode ultrasonography (US). Vastus lateralis (VL) and patellar tendon (PT) stiffness were measured using digital palpation and US across submaximal isometric contractions. Muscle function was evaluated during maximal voluntary isometric contraction (MVIC) of the knee extensors (KEs). Resistance trained had significantly greater PT stiffness and reduced echogenicity (p < 0.01). Resistance trained also had greater strength per body mass (p < 0.05). Muscle echogenicity was strongly associated with strength and rate of torque development (RTD). Patellar tendon passive stiffness was associated with RTD normalized to MVIC (RTDrel; r = 0.44, p < 0.05). Patellar tendon stiffness was greater in RT young women. No predictive models of muscle function incorporated both stiffness and echogenicity. Because RTDrel is a clinically relevant measure of rehabilitation in athletes and can be predicted by digital palpation, this might represent a practical and objective measure in settings where RTD may not be easy to measure directly.

The complementary use of muscle ultrasound and MRI in FSHD: Early versus later disease stage follow-up

OBJECTIVES

Muscle MRI and ultrasound provide complementary techniques for characterizing muscle changes and tracking disease progression in facioscapulohumeral muscular dystrophy (FSHD). In this cohort study, we provide longitudinal data that compares both imaging modalities head-to-head.

METHODS

FSHD patients were assessed at baseline and after five years. Standardized muscle MRI and ultrasound images of five leg muscles were assessed bilaterally. Fat replacement was quantified using MRI fat-fraction (FF) and ultrasound Heckmatt and echogenicity z-scores (EZ-score). Muscle edema was evaluated using T2-weighted turbo inversion recovery magnitude (TIRM) MRI.

RESULTS

Twenty FSHD patients were included. Muscles with normal baseline imaging showed increases in ultrasound EZ-scores (≥1; in 17%) more often than MRI FF increases (≥10%; in 7%) over time. Muscles with only baseline ultrasound abnormalities often showed considerable FF increases (in 22%), and TIRM positivity at follow-up (44%). Muscles with increased FF at baseline showed stable (80%) or increasing FF (20%) over time. EZ-scores of those muscles either increased (23%), decreased (33%) or remained stable (44%).

CONCLUSIONS

Muscle ultrasound may capture accelerated pathological muscle changes in FSHD in early disease, while muscle MRI appears better-suited to detecting and monitoring pathology in later stages.

SIGNIFICANCE

Our results help establish each techniques' optimal use as imaging biomarker.

Ex-vivo validation of spatial gain sonography for the quantification of echo intensity in fascicle-aligned ultrasound images in ten anatomical muscles in Bos taurus

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.

Can segmental bioelectrical impedance be used as a measure of muscle quality?

Recent works have shown bioelectrical impedance spectroscopy (BIS) may assess tissue quality. The purpose of this project was to examine associations between ultrasound echo intensity (EI) of quadriceps muscles (vastus lateralis [VL], vastus medialis [VM], vastus intermedius [VI], rectus femoris [RF]) and BIS parameters (R0, R1, C, α, fp), and if the associations are specific to individual muscles or associated with a representation of the entire quadriceps. Twenty-two participants (age: 22 ± 4 years; BMI: 25.47 ± 3.26 kg/m2) participated in all study activities. Participants had transverse ultrasound scans of each individual quadriceps muscle taken at 25, 50, and 75 % of the muscle length to generate an average EI for the VL, VM, VI, and RF, which were further averaged to generate an EI for the entire quadriceps. For BIS, participants were seated with electrodes placed on the thigh to measure the segmental quadriceps. The Cole-impedance model parameters that best fit the BIS data for each participant was used for all analyses. Pearson's correlation coefficient (r) were calculated to determine associations between muscles' EI and BIS parameters. The results suggest averaged EI of individual VL, VM, VI, RF muscles and the average EI of the segmental quadriceps were significantly related to the R0, C, α metrics of the Cole-impedance model representing quadriceps segmental tissues. This supports that segmental BIS may be an appropriate technique for rapid evaluation of segmental muscle quality.

Effects of Alaska Pollack Protein Ingestion on Neuromuscular Adaptation in Young Healthy Adults: A Randomized, Placebo-Controlled Trial

Alaska pollack protein (APP), has been reported as a protein source that can enhance muscle hypertrophy more than other protein sources in animal studies. This study aimed to examine the effects of APP ingestion on muscle quantity and quality in young adults. Fifty-five young college students were assigned to two groups: APP and placebo (whey protein: WP) groups, and instructed to ingest 4.5 g of each protein in addition to daily meals, and to maintain their usual daily physical activities for 3 mo. Twenty-one and 23 students completed the intervention and were analyzed in APP and WP groups, respectively. The maximum knee extension torque significantly increased in both groups during the intervention. The motor unit discharge rate, which is an indicator of activation, for a given force level significantly decreased in both groups during the intervention, but its decrease in the APP group was significantly greater than in the WP group. Echo intensity of the vastus lateralis evaluated by ultrasound images significantly decreased in both groups. The muscle thickness and skeletal muscle mass did not change. Small amount of additional APP intake induces greater effects on neural activation than WP, suggesting the greater neural economy of generation of force.

The Role of Ultrasound Muscle Parameters for Myosteatosis and Myofibrosis Measurement in Young, Older, and Obese Subjects

OBJECTIVES

The aim of the study was to compare quantitative and qualitative ultrasound parameters between healthy young adults and post-acute hospitalized older adults with and without physical disability, as well as between normal weight and overweight/obese persons.

DESIGN

Cross-sectional observational study.

SETTING AND PARTICIPANTS

A total of 120 individuals were recruited: 24 healthy young adults, 24 normal weight and 24 overweight/obese community-dwelling adults, and 48 post-acute hospitalized older adults with different degrees of functional autonomy.

METHODS

The rectus femoris cross-sectional area (CSA), subcutaneous adipose tissue (SCAT) thickness, echogenicity, strain elastography, and compressibility were measured with ultrasound echography.

RESULTS

Post-acute older adults with a good level of autonomy showed higher echogenicity, a higher compressibility index and elastometry strain, and lower rectus femoris thickness and CSA as compared with young persons. Post-acute individuals with physical disability showed lower echogenicity and a greater stiffness compared with their still autonomous counterparts. Normal weight individuals showed lower stiffness as evaluated with elastometry and a lower SCAT thickness, as compared with individuals with age-matched overweight or obesity. From multiple regression analyses, using CSA as an independent variable, an inverse association with female sex and age was observed, explaining 16% and 51% of variance. Echogenicity was directly associated with age (34% of variance) and with the Barthel index (6% of variance). Elastometry showed association with age and body mass index (BMI), 30% and 16% of variance, respectively. Considering compressibility as a dependent variable, a direct association with age and an inverse association with BMI were observed, with 5% and 11% of variance respectively.

CONCLUSIONS AND IMPLICATIONS

Muscle mass decreases with age and with physical disability. Echogenicity, which increases with age and disability level, seems to be associated with myofibrosis. Conversely, elastometry seems useful in the characterization of muscle quality in overweight or obese individuals and as a reliable indirect measure of myosteatosis.

Effects of plyometric- and cycle-based high-intensity interval training on body composition, aerobic capacity, and muscle function in young females: a field-based group fitness assessment

High-intensity interval training (HIIT) is an effective alternative to moderate intensity continuous training for improvements in body composition and aerobic capacity; however, there is little work comparing different modalities of HIIT. The purpose of this study was to compare the effects of plyometric- (PLYO) and cycle-oriented (CYC) HIIT on body composition, aerobic capacity, and skeletal muscle size, quality, and function in recreationally trained females. Young (21.7 ± 3.1 yrs), recreationally active females were quasi-randomized (1:1 ratio) to 8 weeks of twice weekly PLYO (n = 15) or CYC (n = 15) HIIT. Body composition (four-compartment model), VO2peak, countermovement jump performance, muscle size, and echo intensity (muscle quality), as well as strength and power of the knee extensors and plantar flexors were measured before and after training. Both groups showed a similar decrease in body fat percentage (p < 0.001;η p 2   = 0.409) and echo intensity (p < 0.001;η p 2 = 0.558), and an increase in fat-free mass (p < 0.001;η p 2   = 0.367) and VO2peak (p = 0.001;η p 2 = 0.318). Muscle size was unaffected (p > 0.05), whereas peak torque was reduced similarly in both groups (p = 0.017;η p 2 = 0.188) and rapid torque capacity was diminished only for the knee extensors after CYC (p = 0.022; d = -0.67). These results suggest that PLYO and CYC HIIT are similarly effective for improving body composition, aerobic capacity, and muscle quality, whereas muscle function may express moderate decrements in recreationally active females. ClinicalTrials.gov (NCT05821504).

Ultrasound utilized by registered dietitians for body composition measurement, nutritional assessment, and nutritional management

BACKGROUND AND AIMS

Ultrasound has been used primarily as a tool for body composition measurement in the field of clinical nutrition. Although many recent reports have demonstrated that ultrasound could be a useful tool for nutritional assessment, it is not well incorporated into registered dietitians' (RDs) practice. The aim of this review was to summarize the usefulness of ultrasound in assessing body composition and nutritional status and in nutritional management by RDs.

METHODS

Studies on ultrasonography, nutritionists, body composition, nutritional assessment, and diet therapy was searched using the MEDLINE databases.

RESULTS

After reviewing the articles, we categorized them into the following topics; 1) principles of muscle measurement using the ultrasound, types of muscle that can be measured, 2) indices of muscle and muscle mass and quality as assessed using ultrasound and its relationship to nutritional indicator, 3) diagnosis of the Global Leadership Initiative on Malnutrition (GLIM) criteria malnutrition using ultrasound, 4) practical nutritional management using ultrasound and 5) education and issues for ultrasound implementation. Ultrasound can evaluate low body mass index, unintentional loss of body weight, low skeletal muscle mass index, decreased food intake/assimilation, and disease burden/inflammation, all which are essential items of the phenotypic and etiologic criteria of the GLIM.

CONCLUSION

Ultrasound may be useful for RDs to perform body composition measurement, nutritional assessment, and nutritional management. It will be important to identify the cutoff values for ultrasound-based measurements of muscle mass. In order for RDs to perform a body composition measurement, nutritional assessment, and nutritional management using ultrasound, educational issues need to be addressed.

Association of activities of daily living, mobility and balance ability, and symptoms of Parkinson's disease with the masses and amounts of intramuscular non-contractile tissue of the trunk and lower extremity muscles in patients with Parkinson's disease

PURPOSE

We examined the association of activities of daily living (ADL), mobility and balance ability, and symptoms of Parkinson's disease (PD) with the masses and amounts of intramuscular non-contractile tissue of the trunk and lower extremity muscles in patients with PD.

METHODS

The subjects were 11 community-dwelling patients with PD. ADL were assessed using the Functional Independence Measure. Mobility capacity was assessed based on measurement of maximal walking speed and timed up-and-go time, while balance ability was evaluated based on measurement of one-legged stance time. The symptoms of PD were assessed based on measurement of the Hoehn and Yahr stage and Unified Parkinson's Disease Rating Scale. Muscle thickness (MT) and echo intensity (EI) of the trunk and lower extremity muscles were also measured using an ultrasound imaging device.

RESULTS

Partial correlation analysis revealed an association between reduced ADL and increased EI of the lumbar erector spinae muscle; reduced mobility capacity and increased EI of the rectus abdominis and gluteus minimus muscles; and reduced balance ability and decreased MT of the lumbar erector spinae muscle and increased EI of the lumbar erector spinae, semitendinosus, and tibialis posterior muscles. Partial correlation analysis also showed an association between symptoms of severe PD and decreased MT of the tibialis anterior muscles and increased EI of the lumbar erector spinae, gluteus minimus, and tibialis posterior muscles.

CONCLUSION

The properties of the trunk and lower extremity muscles may be critical for ADL, mobility and balance ability, and symptoms of PD in patients with PD.

Relationship between echogenicity of deep cervical muscles and pain laterality in subjects suffering from cervicogenic headache

OBJECTIVE

This study investigated the deep upper cervical muscles echogenicity in cervicogenic headache (CGH) patients.

METHODS

The echogenicity of longus capitis (LCAP), rectus capitis posterior major (RCPM), and obliquus capitis superior (OCS) muscles was measured by ultrasonography and analyzed by Image J software in 17 CGH patients matched with 17 healthy subjects.

RESULTS

The echogenicity of all muscles in the CGH group was higher than that in healthy subjects. The echogenicity of the LCAP muscle on the right side was significantly different between the CGH and healthy subjects (p< 0.05), but there was no difference in the echogenicity of RCPM and OCS muscles between the groups (p> 0.05). Additionally, the echogenicity differences did not match with the pain side in CGH patients (p> 0.05).

CONCLUSION

Only the deep anterior muscle (LCAP) echogenicity affected by CGH and fatty infiltration occurred in this muscle. Hence, anterior muscle dysfunction is important in CGH diagnosis and treatment.

Effect of subcutaneous adipose tissue and muscle thicknesses on rectus femoris and vastus intermedius ultrasound echo intensities: a cadaver study

PURPOSE

The purpose of this study was to examine the effect of subcutaneous adipose tissue (SCAT) thickness and rectus femoris (RF) muscle thickness on RF and vastus intermedius (VI) echo intensity using human cadavers.

METHODS

The echo intensity of the RF and VI was measured in 11 legs of seven cadavers under three conditions: intact condition (Model 1), SCAT removed (Model 2), and SCAT and RF removed (Model 3).

RESULTS

RF echo intensity in Model 1 (69.2 ± 20.3 a.u.) was significantly lower than that in Model 2 (83.4 ± 15.9 a.u.) (P = 0.003). VI echo intensity in Models 1 to 3 showed similar results to RF echo intensity (P = 0.003 to 0.001). Regarding the relationship between VI echo intensity and VI muscle thickness, the regression lines shifted upward in a parallel fashion in the order Model 1, Model 2, and Model 3. Multiple regression analysis revealed that the variation in RF echo intensity was explained by RF muscle thickness (P = 0.036) and SCAT thickness (P = 0.001), while the variation in VI echo intensity was explained by RF muscle thickness (P = 0.035).

CONCLUSION

These results suggest that SCAT thickness and RF muscle thickness induce lower RF echo intensity, while RF muscle thickness induces lower VI echo intensity.

Accuracy of ultrasound, bioelectrical impedance analysis and anthropometry as point-of-care measurements of skeletal muscle mass in patients with inflammatory bowel disease

BACKGROUND

Disturbance of skeletal muscle mass has clinically important implications in patients with inflammatory bowel disease (IBD), but accurate quantification requires radiation-intense techniques.

AIMS

We aimed to compare point-of-care muscle assessments and their change with therapy with those using reference-standard whole-body dual energy X-ray absorptiometry (DXA).

METHODS

Adult patients with IBD and healthy controls underwent prospective assessment of muscularity by ultrasound of the dominant arm and both thighs, bioelectrical impedance analysis (BIA), anthropometric measurements, and DXA. Patients with active IBD were assessed again ≥13 weeks after initiating biologic induction therapy.

RESULTS

In 54 patients with IBD and 30 controls, all muscle assessments correlated significantly with DXA-derived skeletal muscle index (SMI). In IBD, ultrasound of the arm and legs had the best agreement with DXA-derived SMI (mean difference 0 kg/m2 , 95% limits of agreement -1.3 to 1.3), while BIA overestimated DXA-derived SMI by 1.07 (-0.16 to +2.30) kg/m2 . In 17 patients who underwent biologic therapy, the percentage change in DXA-derived SMI correlated significantly with the percentage change in all other muscle assessment techniques. Responders (n = 9) increased SMI from baseline to follow-up when derived from DXA (mean 7.8-8.5 kg/m2 , p = 0.004), ultrasound of the arm and legs (300-343 cm2 , p = 0.021) and BIA (9.2-9.6 kg/m2 , p = 0.011).

CONCLUSIONS

Ultrasound of the arm and legs out-performed other point-of-care methods in its accuracy of measuring muscle mass. All methods, except mid-arm circumference, were responsive to therapy-induced change. Ultrasound is the preferred non-invasive test for measuring muscle mass in patients with IBD.

Association of Hand Grip Strength with Ultrasound-derived Forearm Muscle Thickness and Echo Intensity in Young Indian Adults

Background

Muscle thickness (MT) quantification, which reflects the muscle function, can be measured using ultrasonography. Echo intensity (EI) quantified from the ultrasonography-derived skeletal muscle images reflects muscle quality. This study aimed to analyze the associations between handgrip strength, ultrasound-measured forearm MT, and EI in healthy young adults.

Methods

Sixty healthy volunteers between the ages of 18 and 25 years participated in the study. Brightness mode ultrasonography (USG) was done to measure forearm radial and ulna MT. The EI was measured from an ultrasound image as a mean pixel value using a histogram in Adobe Photoshop. Individuals were tested for forearm handgrip strength using hand dynamometry.

Results

Males had higher forearm MT and handgrip strength compared to females. Handgrip strength had a significant positive correlation with forearm radius, ulna MT (r = 0.726, 0.757 and P < 0.01), and forearm circumference (r = 0.529 and P < 0.01) and a negatively correlation with subcutaneous fat thickness (r = -0.496 and P < 0.01) and EI (r = -0.618 and P < 0.01). Linear regression showed a significant correlation between MT, circumference, and EI with handgrip strength (r = 0.825 and P < 0.001). After adjustment for the other two parameters, the forearm MT correlated positively and EI negatively with handgrip strength.

Conclusion

USG can be more easily used than other imaging methods in research and clinical setting as it is nonhazardous, less expensive, versatile, and provides results faster. Thus, USG measurements in skeletal muscle are useful for measuring MT and subcutaneous fat thickness. EI measurement can be a convenient and noninvasive method for assessing muscle quality.

Quantification of Extramyocellular Lipids and Intramuscular Fat from Muscle Echo Intensity in Lower Limb Muscles: A Comparison of Four Ultrasound Devices against Magnetic Resonance Spectroscopy

This study aimed to compare different ultrasound devices with magnetic resonance spectroscopy (MRS) to quantify muscle lipid content from echo intensity (EI). Four different ultrasound devices were used to measure muscle EI and subcutaneous fat thickness in four lower-limb muscles. Intramuscular fat (IMF), intramyocellular (IMCL) and extramyocellular lipids (EMCL) were measured using MRS. Linear regression was used to compare raw and subcutaneous fat thickness-corrected EI values to IMCL, EMCL and IMF. IMCL had a poor correlation with muscle EI (r = 0.17-0.32, NS), while EMCL (r = 0.41-0.84, p < 0.05-p < 0.001) and IMF (r = 0.49-0.84, p < 0.01-p < 0.001) had moderate to strong correlation with raw EI. All relationships were improved when considering the effect of subcutaneous fat thickness on muscle EI measurements. The slopes of the relationships were similar across devices, but there were some differences in the y-intercepts when raw EI values were used. These differences disappeared when subcutaneous fat thickness-corrected EI values were considered, allowing for the creation of generic prediction equations (r = 0.41-0.68, p < 0.001). These equations can be used to quantify IMF and EMCL within lower limb muscles from corrected-EI values in non-obese subjects, regardless of the ultrasound device used.

Skeletal Muscle Assessment Using Quantitative Ultrasound: A Narrative Review

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.

Adolescent Marathon Training: Prospective Evaluation of Musculotendinous Changes During a 6-Month Endurance Running Program

OBJECTIVES

Assess changes in lower extremity musculotendinous thickness, tissue echogenicity, and muscle pennation angles among adolescent runners enrolled in a 6-month distance running program.

METHODS

We conducted prospective evaluations of adolescent runners' lower extremity musculotendinous changes at three timepoints (baseline, 3 months, and 6 months) throughout a progressive marathon training program. Two experienced researchers used an established protocol to obtain short- and long-axis ultrasound images of the medial gastrocnemius, tibialis anterior, flexor digitorum brevis, abductor hallicus, and Achilles and patellar tendons. ImageJ software was used to calculate musculotendinous thickness and echogenicity for all structures, and fiber pennation angles for the ankle extrinsic muscles. Repeated measures within-subject analyses of variance were conducted to assess the effect of endurance training on ultrasound-derived measures.

RESULTS

We assessed 11 runners (40.7% of eligible runners; 6F, 5M; age: 16 ± 1 years; running experience: 3 ± 2 years) who remained injury-free and completed all ultrasound evaluation timepoints. Medial gastrocnemius muscle (F_2,20  = 3.48, P = .05), tibialis anterior muscle (F_2,20  = 7.36, P = .004), and Achilles tendon (F_2,20  = 3.58, P = .05) thickness significantly increased over time. Echogenicity measures significantly decreased in all muscles (P-range: <.001-.004), and increased for the patellar tendon (P < .001) during training. Muscle fiber pennation angles significantly increased for ankle extrinsic muscles (P < .001).

CONCLUSIONS

Adolescent runners' extrinsic foot and ankle muscles increased in volume and decreased in echogenicity, attributed to favorable distance training adaptations across the 6-month timeframe. We noted tendon thickening without concomitantly increased echogenicity, signaling intrasubstance tendon remodeling in response to escalating distance.

The relationship between clinical examination measures and ultrasound measures of fascia thickness surrounding trunk muscles or lumbar multifidus fatty infiltrations: An exploratory study

Patients with chronic low back pain (CLBP) exhibit remodelling of the lumbar soft tissues such as muscle fatty infiltrations (MFI) and fibrosis of the lumbar multifidus (LuM) muscles, thickness changes of the thoracolumbar fascia (TLF) and perimuscular connective tissues (PMCT) surrounding the abdominal lateral wall muscles. Rehabilitative ultrasound imaging (RUSI) parameters such as thickness and echogenicity are sensitive to this remodelling. This experimental laboratory study aimed to explore whether these RUSI parameters (LuM echogenicity and fascia thicknesses), hereafter called dependent variables (DV) were linked to independent variables (IV) such as (1) other RUSI parameters (trunk muscle thickness and activation) and (2) physical and psychological measures. RUSI measures, as well as a clinical examination comprising physical tests and psychological questionnaires, were collected from 70 participants with LBP. The following RUSI dependent variables (RUSI-DV), measures of passive tissues were performed bilaterally: (1) LuM echogenicity (MFI/fibrosis) at three vertebral levels (L3/L4, L4/L5 and L5/S1); (2) TLF posterior layer thickness, and (3) PMCT thickness of the fasciae between subcutaneous tissue thickness (STT) and external oblique (PMCTSTT/EO ), between external and internal oblique (PMCTEO/IO ), between IO and transversus abdominis (PMCTIO/TrA ) and between TrA and intra-abdominal content (PMCTTrA/IA ). RUSI measures of trunk muscle's function (thickness and activation), also called measures of active muscle tissues, were considered as independent variables (RUSI-IV), along with physical tests related to lumbar stability (n = 6), motor control deficits (n = 7), trunk muscle endurance (n = 4), physical performance (n = 4), lumbar posture (n = 2), and range of motion (ROM) tests (n = 6). Psychosocial measures included pain catastrophizing, fear-avoidance beliefs, psychological distress, illness perceptions and concepts related to adherence to a home-based exercise programme (physical activity level, self-efficacy, social support, outcome expectations). Six multivariate regression models (forward stepwise selection) were generated, using RUSI-DV measures as dependent variables and RUSI-IV/physical/psychosocial measures as independent variables (predictors). The six multivariate models included three to five predictors, explaining 63% of total LuM echogenicity variance, between 41% and 46% of trunk superficial fasciae variance (TLF, PMCTSTT/EO ) and between 28% and 37% of deeper abdominal wall fasciae variance (PMCTEO/IO , PMCTIO/TrA and PMCTTrA/IA ). These variables were from RUSI-IV (LuM thickness at rest, activation of IO and TrA), body composition (percent fat) and clinical physical examination (lumbar and pelvis flexion ROM, aberrant movements, passive and active straight-leg raise, loaded-reach test) from the biological domain, as well as from the lifestyle (physical activity level during sports), psychological (psychological distress-cognitive subscale, fear-avoidance beliefs during physical activities, self-efficacy to exercise) and social (family support to exercise) domains. Biological, psychological, social and lifestyle factors each accounted for substantial variance in RUSI-passive parameters. These findings are in keeping with a conceptual link between tissue remodelling and factors such as local and systemic inflammation. Possible explanations are discussed, in keeping with the hypothesis-generating nature of this study (exploratory). However, to impact clinical practice, further research is needed to determine if the most plausible predictors of trunk fasciae thickness and LuM fatty infiltrations have an effect on these parameters.

Precision technologies for predictive diagnosis and study of the allometric growth of broiler chickens with breast myopathies

1. An experiment was carried out to validate techniques as predictive diagnostic tools for breast myopathies and to study the allometric growth of distinct parts of the body and meat quality of broilers.2. Infrared thermography was performed at 35 d of age. The surface temperatures of breasts of 300 birds were recorded, followed by ultrasound imaging.3. The birds were slaughtered and the cuts were made to weigh the body parts. Then, the breasts were evaluated as for the presence and severity of myopathies, from which nine treatments were established represented by the associated degrees of the myopathies white striping and wooden breast and breasts classified as normal.4. There was no difference in surface temperatures and echogenicity values between normal breasts and breasts affected by myopathies. At 35 d of age few fillets classified as normal were found.5. The breast showed late growth in relation to the body, regardless of characteristic lesions of myopathies. The most severe score of wooden breast affected meat quality variables.

Serum Adiponectin and Leptin Is Not Related to Skeletal Muscle Morphology and Function in Young Women

Adipokines secreted from adipose tissue, such as adiponectin and leptin, enhance skeletal muscle metabolism. Animal studies have shown that adipokine knockout leads to a reduction in muscle function. Muscle function is determined by muscle size and quality; therefore, it is speculated that lower adipokine levels affect skeletal muscle size and quality, eventually leading to lower muscle function. This study aimed to investigate the relationship between adipokines and skeletal muscle morphology and function in young individuals. A total of 21 young women participated in this study. Adiponectin and leptin levels were analyzed using fasting blood samples from all participants. B-mode ultrasound images of the thigh and calf were obtained, and the muscle thickness and echo intensity were measured in the vastus lateralis (VL) and medial gastrocnemius (MG). The shear modulus was measured from the VL and MG using shear wave elastography. Knee extension and plantar flexion peak torques were measured as muscle functions. Adiponectin and leptin were not related to echo intensity, shear modulus, and muscle thickness in the VL and MG (r_s = -0.26-0.37, P > .05). Furthermore, no relationship was observed between adiponectin, leptin, knee extension, and dorsiflexion peak torque (r_s = -0.28-0.41, P > .05). These negative results suggest that adiponectin and leptin levels in young women are not associated with muscle size and quality, nor are they related to muscle function.

Update on Lean Body Mass Diagnostic Assessment in Critical Illness

Acute critical illnesses can alter vital functions with profound biological, biochemical, metabolic, and functional modifications. Despite etiology, patient's nutritional status is pivotal to guide metabolic support. The assessment of nutritional status remains complex and not completely elucidated. Loss of lean body mass is a clear marker of malnutrition; however, the question of how to investigate it still remains unanswered. Several tools have been implemented to measure lean body mass, including a computed tomography scan, ultrasound, and bioelectrical impedance analysis, although such methods unfortunately require validation. A lack of uniform bedside measurement tools could impact the nutrition outcome. Metabolic assessment, nutritional status, and nutritional risk have a pivotal role in critical care. Therefore, knowledge about the methods used to assess lean body mass in critical illnesses is increasingly required. The aim of the present review is to update the scientific evidence regarding lean body mass diagnostic assessment in critical illness to provide the diagnostic key points for metabolic and nutritional support.

Hamstring Muscle Quality Properties Using Texture Analysis of Ultrasound Images

The aim of this study was to examine the intra- and inter-muscular differences of the hamstring muscles using textural analysis of ultrasound (US) images, and the relationship between textural indicators with hamstring torque. Transverse US scans were obtained from 10 young males from four different measurement sites along the thigh of each individual hamstring muscle at rest. Maximum-knee-flexion isometric torque measurements were also obtained. Texture analysis was applied to US images, and five gray-level co-occurrence matrix (GLCM) features were quantified: entropy (ENT), angular second moment (ASM), inverse difference moment (IDM), contrast (CON) and correlation (COR). The intraclass correlation coefficients ranged from 0.77 to 0.99, and the standard error of measurement ranged from 0.06 to 10.05%, indicating high test-retest reliability. Analysis of the variance indicated significant differences between measurement sites and individual muscles, with the proximal measurement sites having greater values for ASM, IDM and COR and lower values for ENT and CON compared with the distal sites. Additionally, only the COR at the proximal measurement site exhibited a significant relationship (r = -0.66) with strength. The present study indicated significant differences among hamstrings and measurement locations with respect to the textural analysis and may provide a novel indicator of hamstring functional properties.

Muscle mass, quality, and strength; physical function and activity; and metabolic status in cachectic patients with head and neck cancer

BACKGROUND & AIMS

Cancer cachexia is commonly associated with poor prognosis in patients with head and neck cancer (HNC). However, its pathophysiology and treatment are not well established. The current study aimed to assess the muscle mass/quality/strength, physical function and activity, resting energy expenditure (REE), and respiratory quotient (RQ) in cachectic patients with HNC.

METHODS

This prospective cross-sectional study analyzed 64 patients with HNC. Body composition was measured via direct segmental multifrequency bioelectrical impedance analysis, and muscle quality was assessed using echo intensity on ultrasonography images. Muscle strength was investigated utilizing handgrip strength and isometric knee extension force (IKEF). Physical function was evaluated using the 10-m walking speed test and the five times sit-to-stand (5-STS) test. Physical activity was examined using a wearable triaxial accelerometer. REE and RQ were measured via indirect calorimetry. These parameters were compared between the cachectic and noncachectic groups.

RESULTS

In total, 23 (36%) patients were diagnosed with cachexia. The cachectic group had a significantly lower muscle mass than the noncachectic group. Nevertheless, there was no significant difference in terms of fat between the two groups. The cachectic group had a higher quadriceps echo intensity and a lower handgrip strength and IKEF than the noncachectic group. Moreover, they had a significantly slower normal and maximum walking speed and 5-STS speed. The number of steps, total activity time, and time of activity (<3 Mets) did not significantly differ between the two groups. The cachectic group had a shorter time of activity (≥3 Mets) than the noncachectic group. Furthermore, the cachectic group had a significantly higher REE/body weight and REE/fat free mass and a significantly lower RQ than the noncachectic group.

CONCLUSIONS

The cachectic group had a lower muscle mass/quality/strength and physical function and activity and a higher REE than the noncachectic group. Thus, REE and physical activity should be evaluated to determine energy requirements. The RQ was lower in the cachectic group than that in the noncachectic group, indicating changes in energy substrate. Further studies must be conducted to examine effective nutritional and exercise interventions for patients with cancer cachexia.

Ultrasonographic findings in long COVID: A cross-sectional study of 312 patients

Background

Fatigue and muscle weakness are common complaints in COVID-19 survivors. However, little is still known about the skeletal muscle qualitative and quantitative characteristics after hospitalization due to moderate and severe COVID-19.

Objectives

To assess rectus femoris and vastus intermedius muscle thickness (MT) and rectus femoris echo intensity (EI) and to establish its association with demographic, clinical, functional, and inflammatory parameters in long COVID patients after hospital discharge.

Methods

Cross-sectional study with 312 COVID-19 patients (53.53% male; age: 54.59 ± 13.50 years), with a laboratory-confirmed diagnosis of COVID-19. Patients were assessed 3-11 months after hospital discharge. We evaluated MT of the right rectus femoris and vastus intermedius and EI of the right rectus femoris using a portable ultrasound system, 6-13 MHz, broadband linear transducer. We corrected EI using the subcutaneous fat thickness. Ultrasonographic parameters were tested in association with demographic (sex and age); functional (Handgrip strength measurement, Timed Up and Go, 1 min Sit-to-Stand test, EuroQoL-5 Dimensions-5 Levels, World Health Organization Disability Assessment Schedule (WHODAS 2.0), Post-COVID-19 Functional Status, Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT), Medical Research Council (MRC) sum score, Borg Dyspnea Scale, MRC Dyspnea score, Visual Analogue Scale (VAS), Epworth Sleepiness Scale, Insomnia Severity Index, Functional Independence Measurement (FIM), and Functional Oral Intake Scale); clinical (length of hospital stay, intubation, and presence of comorbidities such as systemic hypertension, diabetes, obesity, chronic obstructive pulmonary disease, asthma), and inflammatory data assessed by the C-reactive protein and D-dimer serum concentrations.

Results

Rectus femoris MT was associated with age, handgrip strength, Epworth Sleepiness Scale, and subcutaneous fat thickness (r² = 27.51%; p < 0.0001). Vastus intermedius MT was associated with age, pain intensity, handgrip strength, Epworth Sleepiness scale, FIM, and time since hospital discharge (r² = 21.12%; p < 0.0001). Rectus femoris EI was significantly associated with the male sex, TUG, Epworth Sleepiness Scale, and C-Reactive Protein levels (r² = 44.39%; p < 0.0001). Mean MT of rectus femoris and vastus intermedius are significantly different (p < 0.001).

Conclusion

After hospital discharge, long COVID patients present qualitative and quantitative skeletal muscle characteristics associated with a combination of demographic, clinical, and functional parameters.

Muscular Echo-Intensity of the Quadriceps by Ultrasound Is More Related to Improvement of Gait Independence than Muscle Thickness in Older Inpatients

OBJECTIVES

This study aimed to examine whether the decrease in muscular echo-intensity of the quadriceps by ultrasound in older inpatients is related to the improvement of gait independence than the increase of muscle thickness.

DESIGN

Longitudinal study.

SETTING

Hospital-based study.

PARTICIPANTS

This study included 171 inpatients aged ≥ 65 years (median age: 84.0 [77.0-88.0], 56.1% female). Patients who were able to walk independently at hospital admission were excluded from the study.

MEASUREMENTS

Improvement of gait independence during hospital stay was assessed using the change in Functional Independence Measure (FIM) gait score (i.e., FIM gait score at hospital discharge minus FIM gait score at hospital admission) and FIM gait score at hospital discharge. Muscular echo-intensity and muscle thickness of the quadriceps were assessed at hospital admission and discharge using ultrasound images, respectively. Muscular echo-intensity has been shown to be mainly related to intramuscular adipose tissue. Multiple linear regression analysis was performed to identify the factors independently associated with the change in FIM gait score and FIM gait score at discharge.

RESULTS

Change in quadriceps echo-intensity was independently and significantly associated with the change in FIM gait score (β = -0.22, p = 0.017) and FIM gait score at hospital discharge (β = -0.21, p = 0.017). In contrast, change in quadriceps thickness was not independently and significantly associated with the change in FIM gait score (β = 0.16, p = 0.050) and FIM gait score at hospital discharge (β = 0.15, p = 0.050).

CONCLUSIONS

Our study indicates that a decrease in muscular echo-intensity of the quadriceps by ultrasound is more related to the improvement of gait independence than an increase of muscle thickness in older inpatients. Intervention for intramuscular adipose tissue of the quadriceps may be important for improving gait independence in older inpatients.

Relative contribution of neuromuscular activation, muscle size, and muscle quality to maximum strength output of the thigh muscles in young individuals

This study aimed to investigate the relationship between maximal muscle strength and neuromuscular activation, muscle size, and quality of quadriceps (QF) and hamstring muscles (HM). The study included 24 young men and women. The neuromuscular activation parameter was recorded using a single-channel surface electromyography (EMG) with the root mean square (RMS) during maximal isometric knee extension and flexion from four muscles: rectus femoris and vastus lateralis for QF; biceps femoris and semitendinosus for HM. In addition, the peak torque was measured during the same session. B-mode ultrasonographic transverse images were obtained from the anterior, lateral, and posterior thighs. Furthermore, we calculated the muscle thickness (MT) and echo intensity (EI) of the four muscles as indicators of muscle size and quality. The averaged MT, EI, and absolute RMS of QF were calculated by averaging the values of the rectus femoris and vastus lateralis, and that of HM was calculated by averaging the values of the biceps femoris and semitendinosus. The knee extension peak torque was correlated with EI (r = -0.61, P < 0.01) and RMS (r = 0.53, P < 0.01) in the QF. In contrast, the knee flexion peak torque was correlated with RMS (r = 0.53, P < 0.05) but not with MT and EI in HM. In addition, EI and RMS in QF, and RMS in HM were selected as the major determinants of muscle strength in the stepwise regression analysis. These results suggest that muscle strength is moderately associated with different factors related to the thigh muscles in young individuals.

The Muscle Thickness Assessment Using Ultrasonography is a Useful Alternative to Skeletal Muscle Mass by Bioelectrical Impedance Analysis

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.

Predictors of Sarcopenia in Outpatients with Post-Critical SARS-CoV2 Disease. Nutritional Ultrasound of Rectus Femoris Muscle, a Potential Tool

Background and Objectives: The loss of muscle mass in post-critical COVID-19 outpatients is difficult to assess due to the limitations of techniques and the high prevalence of obesity. Ultrasound is an emerging technique for evaluating body composition. The aim is to evaluate sarcopenia and its risk factors, determining ultrasound usefulness as a potential tool for this purpose according to established techniques, such as the bioimpedance vector analysis (BIVA), handgrip strength, and timed up-and-go test. Methods: This is a transversal study of 30 post-critical COVID-19 outpatients. We evaluated nutritional status by ultrasound (Rectus Femoris-cross-sectional-area (RF-CSA), thickness, and subcutaneous-adipose-tissue), BIVA, handgrip strength, timed up-and-go test, and clinical variables during admission. Results: According to The European Society for Clinical Nutrition and Metabolism and the European Association for the Study of Obesity (ESPEN&EASO) Consensus for Sarcopenic and Obesity, in terms of excess fat mass and decreased lean mass, the prevalence of class-1 sarcopenic obesity was 23.4% (n = 7), and class-2 sarcopenic obesity was 33.3% (n = 10) in our study. A total of 46.7% (n = 14) of patients had a handgrip strength below the 10th percentile, and 30% (n = 9) achieved a time greater than 10s in the timed up-and-go test. There were strong correlations between the different techniques that evaluated the morphological (BIVA, Ultrasound) and functional measurements of muscle. Intensive care unit stay, mechanical ventilation, and age all conditioned the presence of sarcopenia in COVID-19 outpatients (R2 = 0.488, p = 0.002). Predictive models for sarcopenic diagnosis based on a skeletal muscle index estimation were established by RF-CSA (R2 0.792, standard error of estimate (SEE) 1.10, p < 0.001), muscle-thickness (R2 0.774, SEE 1.14, p < 0.001), and handgrip strength (R2 0.856, SEE 0.92, p < 0.001). RF-CSA/weight of 5.3 cm2/kg × 100 was the cut-off value for predicting sarcopenia in post-critical COVID-19 outpatients, with 88.2 sensitivity and 69.2% specificity. Conclusion: More than half of the post-critical COVID-19 survivors had sarcopenic obesity and functional impairment of handgrip strength. Intensive care unit stay, age, and mechanical ventilation all predict sarcopenia. An ultrasound, when applied to the assessment of body composition in post-critical COVID-19 patients, provided the possibility of assessing sarcopenia in this population.

Enhanced echo intensity in vastus medialis is associated with worsening of functional disabilities and symptoms in patients with knee osteoarthritis: a 3 years longitudinal study

Patients with knee osteoarthritis (OA) experience muscle quality loss, and is characterized by the enhanced echo intensity (EI) of the vastus medialis (VM) muscles and a high extracellular water-to-intracellular water (ECW/ICW) ratio of the thigh. This study aimed to elucidate the association between muscle degeneration and the worsening of functional disabilities and symptoms in patients with KOA over 3 years duration. Thirty-three patients with KOA who completed follow-up over 3 years were included in the analysis. The knee scoring system (KSS) was used to evaluate the functional abilities and symptoms. Based on the 3 years change in KSS scores, patients were classified into progressive or non-progressive groups. Muscle thickness (MT) and EI of the VM were determined using ultrasonography. The ECW/ICW ratio was measured using segmental-bioelectrical impedance spectroscopy. Multivariable logistic regression analyses were conducted with the groups as the dependent variables and VM-MT, VM-EI, and ECW/ICW ratio at baseline as independent variables, including potential confounders. Thirteen (39.4%) patients showed progressive features. VM-EI at baseline was significantly associated with the progression of functional disabilities (adjusted odds ratio [OR] 1.24; 95% confidence interval [CI] 1.03 − 1.50) and symptoms (adjusted OR 1.13; 95% CI 1.01 − 1.25). Enhanced VM-EI was associated with the worsening of functional disabilities and symptoms in patients with KOA over a period of 3 years. Therefore, the assessment of VM-EI using ultrasonography is a useful indicator for predicting the future worsening of KOA.

Quantitative assessment of changes in skeletal muscle injury by computer-aided analysis based on two-dimensional ultrasonography combined with contrast-enhanced ultrasonography and estimated by a modified semi-quantitative scoring system: An experimental study in a contusion model

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.

Ultrasound and magnetic resonance imaging as diagnostic tools for sarcopenia in immune-mediated rheumatic diseases (IMRDs)

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.

Ultrasound Assessment of Changes in Muscle Architecture of the Brachialis Muscle After Stroke—A Prospective Study

Objective

To investigate changes in ultrasound-derived muscle architecture parameters of the brachialis and correlations in patients with subacute stroke.

Design

Prospective longitudinal observational study.

Setting

Tertiary inpatient rehabilitation center.

Participants

Fifty adult patients (N=50) who were recruited within the first month poststroke. The patients had a mean age of 57.2±12.3 years and 68.0% were male. The majority of patients had significant upper limb weakness with a low mean Motricity Index of 18.5±24.7 and median elbow flexor strength of grade 0.

Intervention

Not applicable.

Main Outcome Measures

Ultrasound of the intact and hemiparetic brachialis was performed at 3-time intervals: within 1 month of stroke onset and at 1 and 6 months after first assessment. Clinical variables captured included upper limb motor power and elbow flexor spasticity.

Results

Compared to the intact brachialis, there was reduced muscle thickness (1.93 cm vs 2.07 cm, 1.86 cm vs 2.08 cm, 1.85 cm vs 2.05 cm; P=.022) and increased echo intensity (63.3 arbitrary units [AU] vs 56.8 AU, 69.4 AU vs 56.6 AU, 77.4 AU vs 58.2 AU; P<.001) in the hemiparetic brachialis at all assessment intervals (baseline, 1 month, 6 months). Reduction in muscle mass was greater in older patients, with the correlation coefficient ranging from −0.30 (P=.03) at baseline to −0.50 (P<.001) at 6 months. Presence of elbow flexor spasticity at 1-month assessment interval was associated with lower muscle mass reduction (1.93 cm vs 1.74 cm; P=.017), lower echo intensity (65.1 AU vs 75.1 AU; P=.023), and longer fascicle lengths (12.92 cm vs 9.83 cm; P=.002).

Conclusions

Changes including decreased muscle thickness and increased echo intensity of the hemiparetic brachialis were noted over time. Elbow flexor spasticity at 1-month assessment interval appears to mitigate against these changes.

Comparison of Quantitative Ultrasound Methods to Classify Dystrophic and Obese Models of Skeletal Muscle

In this study, we compared multiple quantitative ultrasound metrics for the purpose of differentiating muscle in 20 healthy, 10 dystrophic and 10 obese mice. High-frequency ultrasound scans were acquired on dystrophic (D2-mdx), obese (db/db) and control mouse hindlimbs. A total of 248 image features were extracted from each scan, using brightness-mode statistics, Canny edge detection metrics, Haralick features, envelope statistics and radiofrequency statistics. Naïve Bayes and other classifiers were trained on single and pairs of features. The a parameter from the Homodyned K distribution at 40 MHz achieved the best univariate classification (accuracy = 85.3%). Maximum classification accuracy of 97.7% was achieved using a logistic regression classifier on the feature pair of a² (K distribution) at 30 MHz and brightness-mode variance at 40MHz. Dystrophic and obese mice have muscle with distinct acoustic properties and can be classified to a high level of accuracy using a combination of multiple features.

Relationship Between Muscle Quality or Stiffness Measured by Ultrasonography and Range of Motion in Hospitalized Older Adults

Older adults who require nursing care have joint contractures characterized by limited range of motion (ROM). The present study investigated age-related muscle changes using ultrasonography and the relationship between ROM and muscle changes in older adults. Twenty-two healthy young adults (mean age: 23.3 y) and 60 hospitalized older adults (mean age: 86.1 y) participated. ROM of hip abduction was measured using a goniometer. Echo intensity (EI), reflecting interstitial fibrous tissue or fat within adductor longus (ADDl) was measured using B-mode ultrasonography, and strain ratio (SR), reflecting ADDl stiffness, was measured by strain elastography. The Mann-Whitney U-test and Spearman's correlation test were used for analysis. The ROM and SR of older adults were significantly lower than those of young adults (both p values <0.001). The EI was significantly higher in older adults than in young adults (p < 0.001). In older adults, the SR was moderately correlated with ROM (ρ = 0.49, p < 0.001). In conclusion, limited ROM and increase in interstitial fibrous tissue or fat and stiffness occur with aging, and the SR measured by strain elastography is useful for investigating the effect of muscle stiffness on the ROM of hospitalized older adults.

Neuromuscular electrical stimulation in the intensive care unit prevents muscle atrophy in critically ill older patients: A retrospective cohort study

Critically ill patients in the intensive care unit (ICU) develop muscle atrophy and decreased physical function. Though neuromuscular electrical stimulation (NMES) therapy has been shown to be effective in preventing this, but its effect on older patients is unknown. To examine the course of critically ill older patients treated with NMES in the ICU and to define the impact of its use. A retrospective cohort study was conducted using older ICU patients (≥65 years) categorized into a control group (n = 20) and an NMES group (n = 22). For subgroup analysis, each group was further classified into pre-old age (65-74 years) and old age (≥75 years). The control group showed significant decrease in muscle thickness during ICU and hospital stay. The NMES group showed lower reduction in muscle thickness and showed decrease in muscle echo intensity during hospital stay, compared to the control group. NMES inhibited decrease in muscle thickness in the pre-old age group versus the old age group. The decreasing effect of NMES on echo intensity during hospital stay manifested only in the pre-old age group. We did not find much difference in physical functioning between the NMES and control groups. Lower limb muscle atrophy reduces in critically ill older patients (≥65 years) with NMES and is pronounced in patients aged < 75 years. The impact of NMES on the physical functioning of older patients in ICU needs to be further investigated.

Objective physical activity level is associated with rectus femoris muscle echo‐intensity in patients with chronic obstructive pulmonary disease

Introduction

Skeletal muscle dysfunction is one of the major extrapulmonary complications of chronic obstructive pulmonary disease (COPD). Some studies have reported a relationship between physical activity (PA) level and skeletal muscle quality assessed by echo‐intensity (EI) in healthy individuals but not in patients with COPD.

Objectives

The aim of this study is to investigate the relationships between PA level and both skeletal muscle EI and skeletal muscle mass in patients with COPD.

Methods

We employed a cross‐sectional design. Forty male outpatients with stable COPD were enrolled. Using B‐mode ultrasonography, we measured the rectus femoris muscle cross‐sectional area (RF‐CSA) and EI (RF‐EI). The RF‐CSA and RF‐EI were measured on frozen images using an electronic caliper and 8‐bit gray‐scale analysis, respectively. The objective PA level was determined by monitoring daily step counts and moderate‐to‐vigorous physical activity time (MVPA) with an activity monitor. A general regression model was used to assess the relationships between PA level and both RF‐CSA and RF‐EI. Age and body mass index (BMI) were adopted as confounding variables.

Results

Twenty‐five outpatients with stable COPD (age, 70 ± 7 years old; forced expiratory volume in 1 s, 55.0 ± 24.9% of predicted values) were finally enrolled in the present study. Even after adjusting for age and BMI, the daily step counts and MVPA were significantly associated with RF‐EI, and knee extensor force was associated with RF‐CSA.

Conclusion

The present study showed that PA level was associated with RF‐EI in patients with COPD. In addition, RF‐CSA was associated with knee extensor force. When assessing skeletal muscle using ultrasonography in patients with COPD, we should also assess EI.

The sonographic quantitative assessment of the deltoid muscle to detect type 2 diabetes mellitus: a potential noninvasive and sensitive screening method?

BACKGROUND

In our previous published study, we demonstrated that a qualitatively assessed elevation in deltoid muscle echogenicity on ultrasound was both sensitive for and a strong predictor of a type 2 diabetes (T2DM) diagnosis. This study aims to evaluate if a sonographic quantitative assessment of the deltoid muscle can be used to detect T2DM.

METHODS

Deltoid muscle ultrasound images from 124 patients were stored: 31 obese T2DM, 31 non-obese T2DM, 31 obese non-T2DM and 31 non-obese non-T2DM. Images were independently reviewed by 3 musculoskeletal radiologists, blinded to the patient's category. Each measured the grayscale pixel intensity of the deltoid muscle and humeral cortex to calculate a muscle/bone ratio for each patient. Following a 3-week delay, the 3 radiologists independently repeated measurements on a randomly selected 40 subjects. Ratios, age, gender, race, body mass index, insulin usage and hemoglobin A_1c were analyzed. The difference among the 4 groups was compared using analysis of variance or chi-square tests. Both univariate and multivariate linear mixed models were performed. Multivariate mixed-effects regression models were used, adjusting for demographic and clinical variables. Post hoc comparisons were done with Bonferroni adjustments to identify any differences between groups. The sample size achieved 90% power. Sensitivity and specificity were calculated based on set threshold ratios. Both intra- and inter-radiologist variability or agreement were assessed.

RESULTS

A statistically significant difference in muscle/bone ratios between the groups was identified with the average ratios as follows: obese T2DM, 0.54 (P < 0.001); non-obese T2DM, 0.48 (P < 0.001); obese non-T2DM, 0.42 (P = 0.03); and non-obese non-T2DM, 0.35. There was excellent inter-observer agreement (intraclass correlation coefficient 0.87) and excellent intra-observer agreements (intraclass correlation coefficient 0.92, 0.95 and 0.94). Using threshold ratios, the sensitivity for detecting T2DM was 80% (95% CI 67% to 88%) with a specificity of 63% (95% CI 50% to 75%).

CONCLUSIONS

The sonographic quantitative assessment of the deltoid muscle by ultrasound is sensitive and accurate for the detection of T2DM. Following further studies, this process could translate into a dedicated, simple and noninvasive screening method to detect T2DM with the prospects of identifying even a fraction of the undiagnosed persons worldwide. This could prove especially beneficial in screening of underserved and underrepresented communities.

Ultrasound Measurements of Rectus Femoris and Locomotor Outcomes in Patients with Spinal Cord Injury

Patients with incomplete spinal cord injury have decreased mobility, and many do not recover walking ability. The purpose of this study was to investigate rectus femoris muscle thickness and echo intensity on ultrasound and functional outcomes in these patients. This was a prospective cohort study in an inpatient rehabilitation center, which recruited 40 consecutive patients with incomplete spinal cord injury. The patients underwent an ultrasound assessment at 6 weeks post-injury. Ultrasound measurements were performed using B-mode ultrasound scanning and standardized protocols. Functional outcomes on discharge, including Lower Extremity Muscle Score (LEMS), Functional Independence Measure (FIM), and Walking Index for Spinal Cord Injury II (WISCI II), were measured. Rectus femoris muscle thickness was significantly correlated with discharge LEMS (Spearman’s rho = 0.448; p = 0.004), FIM motor subscale (Spearman’s rho = 0.595; p < 0.001), FIM walk subscale (Spearman’s rho = 0.621; p < 0.001) and WISCI II (Spearman’s rho = 0.531; p < 0.001). The rectus femoris echo intensity was also significantly correlated with discharge LEMS (Spearman’s rho = −0.345; p = 0.029), FIM motor subscale (Spearman’s rho = −0.413; p = 0.008), FIM walk subscale (Spearman’s rho = −0.352; p = 0.026), and WISCI II (Spearman’s rho = −0.355; p = 0.025). We report that a relationship exists between rectus femoris muscle ultrasonographic characteristics and muscle function and ambulatory outcomes after inpatient rehabilitation. Ultrasound muscle measurements are potentially useful in assessing muscle wasting and function in patients with spinal cord injury.

Safety and Feasibility Assessment of Repetitive Vascular Occlusion Stimulus (RVOS) Application to Multi-Organ Failure Critically Ill Patients: A Pilot Randomised Controlled Trial

Muscle wasting is implicated in the pathogenesis of intensive care unit acquired weakness (ICU-AW), affecting 40% of patients and causing long-term physical disability. A repetitive vascular occlusion stimulus (RVOS) limits muscle atrophy in healthy and orthopaedic subjects, thus, we explored its application to ICU patients. Adult multi-organ failure patients received standard care +/- twice daily RVOS {4 cycles of 5 min tourniquet inflation to 50 mmHg supra-systolic blood pressure, and 5 min complete deflation} for 10 days. Serious adverse events (SAEs), tolerability, feasibility, acceptability, and exploratory outcomes of the rectus femoris cross-sectional area (RFCSA), echogenicity, clinical outcomes, and blood biomarkers were assessed. Only 12 of the intended 32 participants were recruited. RVOS sessions (76.1%) were delivered to five participants and two could not tolerate it. No SAEs occurred; 75% of participants and 82% of clinical staff strongly agreed or agreed that RVOS is an acceptable treatment. RFCSA fell significantly and echogenicity increased in controls (n = 5) and intervention subjects (n = 4). The intervention group was associated with less frequent acute kidney injury (AKI), a greater decrease in the total sequential organ failure assessment score (SOFA) score, and increased insulin-like growth factor-1 (IGF-1), and reduced syndecan-1, interleukin-4 (IL-4) and Tumor necrosis factor receptor type II (TNF-RII) levels. RVOS application appears safe and acceptable, but protocol modifications are required to improve tolerability and recruitment. There were signals of possible clinical benefit relating to RVOS application.