Architectural anatomy of the quadriceps and the relationship with muscle strength: An observational study utilising real-time ultrasound in healthy adults

Constitutional thinness might be characterized by physiologically adapted and not impaired muscle function and architecture: new results from the NUTRILEAN study

PURPOSE

While muscle mass and skeletal muscle fibers phenotype have been shown atypical in constitutional thinness (CT), force production capacities and its architectural determinants have never been explored. The present study compared muscle functionality and architecture between participants with CT and their normal-weight (NW) counterparts.

METHODS

Anthropometry, body composition (Dual-X-ray Absorptiometry), physical activity/sedentary behavior (ActiGraph wGT3X-BT), ultrasound recording of the Vastus Lateralis (2D-ultrasound system), and functional capacities at maximal isometric and isokinetic voluntary contractions (MVCISO and MVCCON) during knee extension (isokinetic dynamometer chair Biodex) have been measured in 18 women with CT (body mass index < 17.5 kg/m2) and 17 NW women.

RESULTS

A lower fat-free mass (ES: -1.94, 95%CI: -2.76 to -1.11, p < 0.001), a higher sedentary time, and a trend for a lower time spent at low-intensity physical activity, were observed in CT vs NW participants. While absolute MVCISO, MVCCON, rate of torque development (RTD), and torque work were all markedly lower in CT, these differences disappeared when normalized to body or muscle mass. Muscle thickness and fascicle length were found lower in CT (ES: -1.29, 95%CI: -2.03 to -0.52, p < 0.001; and ES: -0.87, 95%CI: -1.58 to -0.15, p = 0.02, respectively), while pennation angle was found similar.

CONCLUSION

Despite lower absolute strength capacities observed in CT, present findings support the hypothesis of physiological adaptations to the low body and muscle mass than to some intrinsic contractile impairments. These results call for further studies exploring hypertrophy-targeted strategies in the management of CT.

MyoVision-US: an Artificial Intelligence-Powered Software for Automated Analysis of Skeletal Muscle Ultrasonography

Introduction/Aims

Muscle ultrasound has high utility in clinical practice and research; however, the main challenges are the training and time required for manual analysis to achieve objective quantification of morphometry. This study aimed to develop and validate a software tool powered by artificial intelligence (AI) by measuring its consistency and predictability of expert manual analysis quantifying lower limb muscle ultrasound images across healthy, acute, and chronic illness subjects.

Methods

Quadriceps complex (QC [rectus femoris and vastus intermedius]) and tibialis anterior (TA) muscle ultrasound images of healthy, intensive care unit, and/or lung cancer subjects were captured with portable devices. Automated analyses of muscle morphometry were performed using a custom-built deep-learning model (MyoVision-US), while manual analyses were performed by experts. Consistency between manual and automated analyses was determined using intraclass correlation coefficients (ICC), while predictability of MyoVision -US was calculated using adjusted linear regression (adj.R 2 ).

Results

Manual analysis took approximately 24 hours to analyze all 180 images, while MyoVision - US took 247 seconds, saving roughly 99.8%. Consistency between the manual and automated analyses by ICC was good to excellent for all QC (ICC:0.85-0.99) and TA (ICC:0.93-0.99) measurements, even for critically ill (ICC:0.91-0.98) and lung cancer (ICC:0.85-0.99) images. The predictability of MyoVision-US was moderate to strong for QC (adj.R 2 :0.56-0.94) and TA parameters (adj.R 2 :0.81-0.97).

Discussion

The application of AI automating lower limb muscle ultrasound analyses showed excellent consistency and strong predictability compared with human analysis. Future work needs to explore AI-powered models for the evaluation of other skeletal muscle groups.

Application of conventional ultrasound coupled with shear wave elastography in the assessment of muscle strength in patients with type 2 diabetes

Background

In patients with type 2 diabetes mellitus (T2DM), a decrease in muscle function may be related to changes in the biomechanical properties of skeletal muscles. However, the correlations between muscle function and the characteristics of muscle size and stiffness as measured by ultrasound in patients with T2DM are unclear. The aim of this study was to investigate the abilities of conventional ultrasound and shear wave elastography (SWE) to assess muscle properties in patients with T2DM and to correlate the findings with isokinetic muscle testing and functional tests.

Methods

Sixty patients from the Department of Endocrinology in The Third Affiliated Hospital of Southern Medical University diagnosed with T2DM were recruited in this cross-sectional study from September 2021 to September 2022. T2DM was defined based on the American Diabetes Association criteria. The exclusion criteria were a history of injury or operation of the lower limb or clinical signs of neuromuscular disorders, any muscle-induced disease, and the presence of other types of diabetes mellitus. Thirty-five matched healthy volunteers were continuously included in the control group. SWE was used to measure the muscle stiffness of the quadriceps femoris [vastus lateralis (VL), rectus femoris (RF), vastus medialis (VM), vastus intermedius (VI)] and the biceps brachii (BB) in a relaxed position, and the shear wave velocity (SWV) values were recorded. Muscle size was measured using conventional ultrasound. The participants underwent isokinetic knee extension/flexion (60°/sec) to assess muscle strength and functional tests of physical performance, including the short physical performance battery, 30-s chair stand test, timed up-and-go test, and 6-meter walk test. All demographics and measured variables were compared using the independent samples t-test. Interclass correlation coefficient analysis was performed on the measurement data obtained by the two operators, and Pearson correlation coefficients were used to determine the relationships between variables.

Results

Patients with T2DM exhibited worse physical performance (P<0.05) and weaker lower limb muscle strength (P<0.05) than did healthy controls, but their handgrip strength was comparable (P=0.102). Patients with T2DM had significantly decreased muscle thickness [RF thickness: 10.69±3.21 vs. 13.09±2.41 mm, mean difference =-2.40, 95% confidence interval (CI): -3.56 to -1.24, P<0.001; anterior quadriceps thickness: 23.45±7.11 vs. 27.25±5.25 mm, mean difference =-3.80, 95% CI: -6.33 to -1.26, P=0.004] and RF cross-sectional area (3.04±1.10 vs. 4.11±0.95 cm2, mean difference =-1.07, 95% CI: -1.49 to -0.64; P<0.001) compared to healthy controls. Smaller muscle size was associated with decreased muscle strength (r=0.44-0.69, all P values <0.001). Except for the BB (3.48±0.38 vs. 3.61±0.61 m/s, mean difference =-0.12, 95% CI: -0.35 to 0.11; P=0.257) and VI (2.59±0.34 vs. 2.52±0.23 m/s, mean difference =0.03, 95% CI: -0.06 to 0.18; P=0.299), the muscle stiffness in patients with T2DM was significantly decreased. For the patients with T2DM and healthy participants, the SWV of the RF was 1.66±0.23 and 1.83±0.18 m/s (mean difference =-0.17, 95% CI: -0.25 to -0.08; P<0.001), respectively; that of the VM was 1.34±0.15 and 1.51±0.16 m/s (mean difference =-0.17, 95% CI: -0.24 to -0.10; P<0.001), respectively; and that of VL was 1.38±0.19 and 1.53±0.19 m/s (mean difference =-0.15, 95% CI: -0.23 to -0.07; P<0.001), respectively. Excellent interobserver reliability of the SWV measurements on the muscle of T2DM patients was observed (all intraclass correlation coefficients >0.75; P<0.001). The SWV showed moderate correlations with muscle strength in the RF, VM, and VL (r=0.30-0.61; all P values <0.05).

Conclusions

Ultrasound technology exhibits good reliability for repeated measurements of muscle size and stiffness. Reduced muscle stiffness as detected by SWE was demonstrated in patients with diabetes and was associated with decreased muscle strength and impaired functional activity.

Muscle mass loss measured with portable ultrasound in hospitalized older adults: The ECOSARC study

OBJECTIVES

The main objective was to analyze the evolution of muscle of the Quadriceps Rectus Femoris (QRF) between admission and discharge, in older adults hospitalized with an acute medical disease in Acute Geriatric Units (AGUs).

DESIGN

Prospective multicentric observational cohort study.

SETTING

Seven AGUs from University Hospitals in Spain.

PARTICIPANTS

Hospitalized adults ≥ 70 years old, able to ambulate and without severe dementia.

MEASUREMENTS

Ultrasound measurements of QRF were acquired at 2/3 distal between anterior-superior iliac spine and patella in both legs by trained Geriatricians. Ultrasound Chison model ECO2 was used. QRF area, thickness, edema, echogenicity, and fasciculations were measured.

RESULTS

From the complete sample (n = 143), in 45 (31.5%) participants, ultrasound images were classified as non-valid by an expert radiologist. Mean age was 87.8 (SD 5.4). Mean hospital stay 7.6 days (SD 4.3). From those with valid images, 36 (49.3%), 2 (2.7%), and 35 (47.9%) presented a decrease, equal values, or an increase in QRF area from baseline to discharge, respectively, and 37 (50.0%), 2 (2.7%), and 35 (47.3%) presented a decrease, equal values, or an increase in QRF thickness, respectively. 26 (35.6%) presented a decrease in more than 0.2 cm2 of QRF area, and 23 (31.1%) a decrease in more than 0.1 cm of QRF thickness. Only 4 (5.4%) patients presented new edema, while 13 (17.6%) worsened echogenicity.

CONCLUSION

One third of older adults develop significant muscle loss during a hospitalization for acute medical diseases.

TRIAL REGISTRATION NUMBER

NCT05113758.

Comparison of the asymmetries in muscle mass, biomechanical property and muscle activation asymmetry of quadriceps femoris between patients with unilateral and bilateral knee osteoarthritis

Background: More and more attention has been paid to the research of muscle mass and muscle quality of quadriceps femoris (QF) in knee osteoarthritis (KOA). This study aimed to explore the asymmetric changes of muscle mass, biomechanical property and muscle activation in the inter-limbs QF of KOA patients, and tried to provide a novel insight for the evaluation, prevention and treatment of KOA. Methods: A total of 56 Participants with unilateral or bilateral KOA were included in this study: 30 patients with unilateral pain and 26 patients with bilateral pain were assigned to the bilateral group (BG) and unilateral group (UG), respectively. The symptom severity of bilateral lower limbs was evaluated by visual analogue scale, and the relatively serious leg (RSL) and relatively moderate leg (RML) were classified. The thickness of rectus femoris (RF), vastus intermedius (VI), vastus medialis (VM) and vastus lateralis (VL) were measured by ultrasound. The Shear wave elastography (SWE) techniqie was used to measure the shear modulus of RF, VM and VL. Surface electromyography (sEMG) was used to assess the root mean square (RMS) of the RF, VM, and VL during straight leg raising in a sitting position and squatting task. We calculated the asymmetry indexes of inter-limbs for the corresponding indices of the measured muscles. Result: Thickness of RF, VI and VL of RSL was lower than those on RML (p < 0.05), and thickness of VM was lower more significant (p < 0.01). Thickness of RF, VI and VL of RSL was also lower than those of RML in BG (p < 0.05), however, there was no significant difference in VM thickness (p > 0.05). There were no significant difference in Asymmetry indexes of all measured muscle thickness between the two groups (p > 0.05). The Shear modulus of RF, VM, and VL in the RML of UG and BG was higher than those in the RSL (p < 0.05). In sitting and straight leg raising task, the RMS of RF, VM and VL in RML were higher than those in RSL, UG and BG both showed this trend (p < 0.05). About squatting task, in UG, the RMS of the three muscles in RML of patients were also higher than those in the RSL (p < 0.05). However, the difference was not significant in BG (p > 0.05). In the straight leg raising task, the asymmetry indexes of RMS in RF, VM, and VL of both the two groups were positively correlated with VAS scores (p < 0.05). Conclusion: The muscle thickness, shear modulus and muscle activation electromyography of QF in RML were higher than those of RSL in unilateral KOA patients. The VM of RML in bilateral KOA patients may show muscle thickness degeneration earlier, which is closer to the VM of RSL. The shear modulus of RF, VM, and VL were higher on the RML side during the single-leg task, but there may be passive compensation for muscle activation in both lower limbs during the bipedal task. In conclusion, there is a general asymmetry of QF muscle mass, biomechanics Characteristic and performance in patients with KOA, which may provide new ideas for the assessment, treatment and rehabilitation of the disease.

Physiotherapeutic interventions on quadriceps muscle architecture in patello-femoral pain syndrome

Quadriceps weakness and morphological alteration is a documented phenomenon that can have a major impact on strength and functional performance of PFPS patients. An effective and trustworthy non-invasive technique for measuring the quadriceps muscle's anatomy and architecture is B- Mode Ultrasonography. The aim of the study is to assess and compare the effectiveness of neuromuscular electrical stimulation application, quadriceps strengthening and in combination on the quadriceps muscle architecture and functional capacity in patients with Patello femoral pain syndrome. One hundred and twenty-four participants aged 18 - 40 years old with anterior knee pain were included. Participants were randomly allocated into four groups. Group A participants were given NMES, group B were given QS, group C were given combination therapy (NMES+QS) and group D was control group. Cross sectional area, Fascicle length and pennation angle were measured using B-Mode (2D) ultrasound for Quadriceps Femoris muscle. Knee function and pain were assessed using Kujala score and VAS. All parameters were evaluated before and after the intervention. The mean age, weight, height and BMI of control, NMES, QS and NMES+QS were not statistically significant (P = 0.881, 0.960, 0.951 and 0.953) which shows that the control and experimental groups were homogenous. Combination group showed significant improvement when compared to QS group followed by NMES group. Control group did not show any improvement. Neuromuscular Electrical Stimulation in combination with quadriceps strengthening showed a better outcome than in isolation on quadriceps muscle architecture after 10 weeks.

Effects of Knee Extension Joint Angle on Quadriceps Femoris Muscle Activation and Exerted Torque in Maximal Voluntary Isometric Contraction

This study investigated the effects of knee joint angle on muscle activation, exerted torque, and whether the knee angle affects the muscle activation−torque ratio. Nine healthy adult male participants participated in the study. They performed maximal voluntary isometric contraction (MVIC) at six (80°, 90°, 100°, 110°, 120°, and 130°) different knee joint angles (i.e., angles between the thigh and shin bones). Their maximal torque was assessed utilizing an isokinetic chair, while their muscle activation (root mean square [RMS]) was assessed using an eight-channel single differential surface EMG sensor. For the purposes of the torque−knee angle relationship and muscle activation−knee angle relationship, the torque and RMS were normalized relative to the maximal value obtained by each participant. To evaluate the muscle activation−torque ratio in function of knee angle, RMS was normalized relative to the corresponding torque obtained at each knee angle. Repeated measure analysis of variance was used to investigate the effects of knee angle on muscle activation, torque, and muscle activation−torque ratio. There was a significant effect of knee joint angle on normalized torque (F = 27.521, p < 0.001), while the activation of vastus lateralis and vastus medialis remained unchanged. The changes in knee angle affected the muscle activation−torque ratio of vastus lateralis (Chi-square = 16.246, p = 0.006) but not the vastus medialis. These results suggest that knee joint angles from 80° to 130° provide a stable milieu for muscle electrification, while mechanical factor such as knee joint angle (i.e., lever arm length) affect the torque output when one needs to contract quadriceps maximally during the isometric contraction.

Ultrasonography, Microcomputed Tomography, and Macroscopic Preparation in an Anatomical Study of the Thoracic Limb of the Golden-Headed Lion Tamarin (Leontopithecus chrysomelas)

The aim of this study was to evaluate the normal anatomy of the forearm of the golden-headed lion tamarin (Leontopithecus chrysomelas) using microcomputed tomography (micro-CT) and ultrasonography (US) and then compare the results with the results of a gross anatomy dissection of the forearm. The results of the US examination of the musculoskeletal system of the tamarin forearm were not satisfactory. US imaging enabled observation of the shape of the soft tissue and the size of muscle groups; however, we distinguished more muscles by traditional methods. In addition, in the dissection study, the assessment of the muscles was easier. Examination of the forearm bones using micro-CT provided a complete picture of the bones in this part of the body and was less time-consuming than traditional methods. Imaging allows the anatomy to be represented as a 3D image. However, some methods are not accurate; as in our study, US did not allow a complete assessment of the forearm musculature.