Rectus Femoris Muscle Cross-sectional Area Research Articles

Acute muscle loss assessed using panoramic ultrasound in critically ill adults: a prospective observational study.

Panoramic ultrasound is one of the recently introduced ultrasound evaluation techniques. We herein examined the relationship between the cross-sectional area of the rectus femoris muscle on panoramic ultrasound and its volume based on the gold standard computed tomography (CT) evaluation. This was a single-center prospective observational study. A panoramic ultrasound assessment of the cross-sectional area of the rectus femoris muscle and a simple CT evaluation of its volume were performed on days 1 and 7 of hospitalization. Physical functions were assessed at discharge. Twenty patients were examined. The rate of change in the cross-sectional area of the rectus femoris muscle on panoramic ultrasound correlated with that in its volume on CT (correlation coefficient 0.59, p = 0.0061). In addition, a correlation was observed between the absolute value for the rectus femoris muscle cross-sectional area on panoramic ultrasound and physical functions at discharge. Rectus femoris muscle distances did not correlate with either. In the acute phase of critical illness, the cross-sectional area of the rectus femoris muscle on panoramic images correlated with its volume on CT and, thus, it is a valid method for assessing muscle mass.

Construct and criterion validity of muscle ultrasonography for assessment of skeletal muscle in patients recovering from COVID-19.

Background: The purpose was to investigate the content, construct, and criterion validity of muscle ultrasound in a mixed cohort of participants recovering from mild and critical COVID-19. Methods: A secondary analysis of a prospective cross-sectional study was conducted on data obtained from a battery of muscle and physical function assessments including a muscle biopsy and muscle ultrasonography (US). Rectus femoris (RF) muscle thickness (mT), quadricep complex (QC) mT, RF muscle cross-sectional area (CSA) using 2D freeform trace and estimated from Feret's diameter, and RF echo intensity (EI) were assessed with US. Muscle fiber CSA, fiber type, protein content in muscle fibers, extracellular matrix content (ECM; wheat-germ agglutin), and percent area of collagen in ECM (picrosirius red) were examined from vastus lateralis muscle biopsies. Spearman rho correlations (r) were performed to assess validity of ultrasound parameters. Results: Thirty-three individuals participated including 11 patients surviving critical COVID-19, 15 individuals recovering from mild-COVID, and 7 controls. There were several significant correlations between RF mT, QC mT, RF CSA, and RF EI with age, comorbid burden, body-mass index, and measures of muscle strength, muscle power, and physical function (range r = 0.35-0.83). RF Feret's CSA correlated to CSA of type II muscle fibers (r = 0.41, p = 0.022) and the average size of all muscle fibers (r = 0.39, p = 0.031). RF EI was correlated with collagen in muscle ECM (r = 0.53, p = 0.003) and protein content in muscle tissue (r = -0.52, p = 0.012). Conclusion: Muscle size and quality measured using US has moderate content and construct validity, and to lesser extent, fair to moderate criterion validity in a mixed cohort of individuals recovering from COVID. Muscle ultrasound quality (EI) appears to be sensitive at detecting muscle dysfunction as it is associated with strength, power, physical function, and collagen distribution in a mixed group of individuals recovering from COVID-19.

Correlation between rectus femoris muscle cross-sectional area and the severity of airflow limitation in COPD patients

Peripheral muscle dysfunction is a well-recognized complication of COPD associated with exercise (in)tolerance and worse prognosis. The evaluation of peripheral muscle integrity is an attractive marker in COPD patients.The aim of the study was to identify the correlation between the rectus femoris muscle cross-sectional area (RFCSA) and the severity of airway obstruction in COPD patients using ultrasound.The study enrolled 24 outpatients diagnosed with stable COPD (post-bronchodilator FEV1/FVC < 0.001*. There was a significant negative correlation between RFCSA and age only in cases with very severe airflow limitation. Among COPD patients, there was a significant negative correlation between average RFCSA and mMRC score (r = − 0.864*, p < 0.001*), but not with FEV1 (r = 0.165, p = 0.442). No significant correlation between average RFCSA and neither CRP nor heart rate in COPD patients (r = − 0.169, p = 0.431, r = − 0.285, p = 0.178, respectively. Among COPD, there was a significant positive correlation between RFCSA and QMVC (r = 0.881*, p < 0.001*). COPD cases showed reduced RFCSA, reduced QMVC, shorter 6MWD distance, and higher mMRC score in comparison to the control group.Ultrasound measurement of RFCSA is an effort-independent, radiation-free method that relates to strength and should be applied as an assessment tool for COPD patients.

Ultrasound-based upper limb muscle thickness is useful for screening low muscularity during intensive care unit admission: A retrospective study

Malnutrition is associated with poor outcomes. Muscle mass is an important malnutrition indicator included in Global Leadership Initiative on Malnutrition (GLIM) criteria. Although bioelectrical impedance analysis and dual-energy X-ray absorptiometry are common muscle mass assessment methods, they are unreliable during intensive care unit (ICU) admission due to the influence of dynamic fluid changes. We hypothesized that ultrasound-based upper limb muscle assessment would be useful for assessing muscularity at ICU admission. We retrospectively analyzed prospectively obtained ultrasound data from patients admitted to an ICU. We excluded patients without computed tomography (CT) imaging of the third lumbar vertebra within 2 days of ICU admission. Primary outcomes were the diagnostic utility of ultrasound-based upper limb muscle thickness for assessing low muscularity by CT. Low muscularity was defined as a skeletal muscle index of 36.0cm2/m2 for males and 29.0cm2/m2 for females at the cross-sectional area of the third lumbar vertebrae. Secondary outcomes of this study included the relationships between upper limb muscle thickness and biceps brachii muscle cross-sectional area, quadriceps femoris thickness, rectus femoris cross-sectional area. Among 64 patients assessed by ultrasound, 52 had CT examination records and were included in the analysis. The mean age was 70±13 years, and the mean body mass index was 23.3±4.2kg/m2. Upper limb muscle thickness had the discriminative power to assess low muscularity at an area under the curve of 0.77 (95% CI [confidence interval], 0.63-0.91); the cutoff value (26.8cm) had 84.6% sensitivity and 66.7% specificity. The upper limb muscle index had the discriminative power to assess low muscularity at an area under the curve of 0.80 (95% CI, 0.68-0.93); the cutoff value (9.9mm/m2) had 76.9% sensitivity and 71.8% specificity. Upper limb muscle thickness was correlated with upper limb muscle cross-sectional area, quadriceps femoris muscle thickness, rectus femoris muscle cross-sectional area (r=0.39-0.76, p<0.01, n=52). Ultrasound-based upper limb muscle thickness assessments can screen for low muscularity upon ICU admission.

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

IntroductionSkeletal 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.ObjectivesThe 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.MethodsWe 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.ResultsTwenty‐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.ConclusionThe 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.

Low-frequency electrical stimulation alleviates immobilization-evoked disuse muscle atrophy by repressing autophagy in skeletal muscle of rabbits

BackgroundThe study aimed to investigate the effect of low-frequency electrical stimulation (LFES) on disuse muscle atrophy and its mechanism in a rabbit model of knee extension contracture.MethodsThis study involved two experiments. In the time-point experiment, 24 rabbits were randomly divided into 4 groups: Control 1 (Ctrl1 group), immobilization for 2 weeks (I-2 group), immobilization for 4 weeks (I-4 group), and immobilization for 6 weeks (I-6 group). In the intervention experiment, 24 rabbits were randomly divided into 4 groups: Control 2 (Ctrl2 group), electrical stimulation (ESG group), natural recovery (NRG group), and electrical stimulation treatment (ESTG group). All intervention effects were assessed by evaluating the knee joint range of motion (ROM), cross-sectional area (CSA) of the rectus femoris muscle, and expression of autophagy-related proteins.ResultsThe time-point experiment showed that immobilization reduced the knee ROM, reduced the rectus femoris muscle CSA, and activated autophagy in skeletal muscle. The levels of five autophagy-related proteins [mammalian target of rapamycin (mTOR), phosphorylated mTOR (p-mTOR), autophagy-related protein 7 (Atg7), p62, and microtubule-associated protein light chain 3B-II (LC3B-II)] were significantly elevated in the skeletal muscle of the I-4 group. The intervention experiment further showed that LFES significantly improved the immobilization-induced reductions in ROM and CSA. Additionally, LFES resulted in a significant decrease in the protein expression of mTOR, p-mTOR, Atg7, p62, and LC3B-II in the rectus femoris muscle.ConclusionsLFES alleviates immobilization-evoked disuse muscle atrophy possibly by inhibiting autophagy in the skeletal muscle of rabbits.

Ultrasound assessment of muscle mass has potential to identify patients with low muscularity at intensive care unit admission: A retrospective study.

Muscle mass is an important biomarker of survival from a critical illness; however, there is no widely accepted method for routine assessment of low muscularity at intensive care unit (ICU) admission. We hypothesize that ultrasound-based partial muscle mass assessments can reflect the trunk muscle mass. Therefore, we aimed to investigate whether ultrasound muscle mass measurements could reflect trunk muscle mass and identify patients with low muscularity. We performed a retrospective analysis of prospectively obtained ultrasound data at ICU admission. We included patients who underwent computed tomography (CT) imaging at the third lumbar vertebra (L3) within 2 days before and 2 days after ICU admission. Primary outcomes included the correlation between the femoral muscle mass measurements using ultrasound and the cross-sectional area (CSA) at L3 obtained by CT. Low muscularity was defined as a skeletal muscle index of 36.0cm2/m2 for males and 29.0cm2/m2 for females. Secondary outcomes included the correlation with the ultrasound measurements of the biceps brachii muscle mass and diaphragm thickness. Among 133 patients, 89 underwent CT imaging, which included the L3. The patient mean age was 72±13 years, and 60 patients (67%) were male. The correlation between the femoral muscle ultrasound and CT was ρ=0.57 (p<0.01, n=89) and ρ=0.48 (p<0.01, n=89) for quadriceps muscle layer thickness and rectus femoris muscle CSA, and these had the discriminative power to assess low muscularity, with the areas under the curve of 0.84 and 0.76, respectively. The ultrasound measurements of the biceps brachii muscle mass and diaphragm thickness were correlated with CT imaging [ρ=0.57-0.60 (p<0.01, n=52) and ρ=0.35 (p<0.01, n=79)]. Ultrasound measurements of muscle mass were correlated with CT measurements, and the measurements of femoral muscle mass were useful to assess low muscularity at ICU admission. UMIN000044032 (retrospectively registered on April 25, 2021).

Effect of Intermittent or Continuous Feed on Muscle Wasting in Critical Illness: A Phase 2 Clinical Trial

Acute skeletal muscle wasting in critical illness is associated with excess morbidity and mortality. Continuous feeding may suppress muscle protein synthesis as a result of the muscle-full effect, unlike intermittent feeding, which may ameliorate it. Does intermittent enteral feed decrease muscle wasting compared with continuous feed in critically ill patients? In a phase 2 interventional single-blinded randomized controlled trial, 121 mechanically ventilated adult patients with multiorgan failure were recruited following prospective informed consultee assent. They were randomized to the intervention group (intermittent enteral feeding from six 4-hourly feeds per 24 h, n= 62) or control group (standard continuous enteral feeding, n= 59). The primary outcome was 10-day loss of rectus femoris muscle cross-sectional area determined by ultrasound. Secondary outcomes included nutritional target achievements, plasma amino acid concentrations, glycemic control, and physical function milestones. Muscle loss was similar between arms (-1.1%[95%CI, -6.1%to -4.0%]; P= .676). More intermittently fed patients received 80%or more of target protein (OR, 1.52 [1.16-1.99]; P< .001) and energy (OR, 1.59 [1.21-2.08]; P= .001). Plasma branched-chain amino acid concentrations before and after feeds were similar between arms on trial day 1 (71 μM [44-98 μM]; P= .547) and trial day 10 (239 μM [33-444 μM]; P= .178). During the 10-day intervention period the coefficient of variation for glucose concentrations was higher with intermittent feed (17.84 [18.6-20.4]) vscontinuous feed (12.98 [14.0-15.7]; P< .001). However, days with reported hypoglycemia and insulin usage were similar in both groups. Safety profiles, gastric intolerance, physical function milestones, and discharge destinations did not differ between groups. Intermittent feeding in early critical illness is not shown to preserve muscle mass in this trial despite resulting in a greater achievement of nutritional targets than continuous feeding. However, it is feasible and safe. ClinicalTrials.gov; No.: NCT02358512; URL: www.clinicaltrials.gov.

Associations Between Muscle Morphology Measured with Ultrasonography and Self-Reported Function Following Anterior Cruciate Ligament Reconstruction

Deficits in quadriceps function are common in patients who sustain an anterior cruciate ligament (ACL) injury and undergo subsequent ACL reconstruction (ACLR). Quadriceps atrophy is among the notable changes in muscle tissue after ACLR. The relationship between muscle morphology and self-reported function should be established so treatment options can be targeted to improve function after ACLR. PURPOSE: (1) To evaluate rectus femoris (RF) cross-sectional area (CSA) and intramuscular fat percent (PF) in the injured and uninjured limb from 9 weeks post ACLR to return to activity (RTA) and (2) identify associations between injured limb quadriceps CSA, PF and self-reported function. METHODS: 28 individuals with primary unilateral ACLR (Age=16.6±2.7; Weight=71.8±17.7; 64% female; 18 bone-patellar tendon-bone; 2 quadriceps tendon; 5 hamstring tendon) were recruited for this study. RF was imaged at 15cm proximal of superior border of the patella. Quadriceps CSA and PF of the injured and uninjured limb were used for analysis. Self-reported function was evaluated using the International Knee Documentation Committee score (IKDC). Paired-samples t-tests were used to compare inter-limb differences in CSA and PF and changes from 9 weeks to RTA. Partial correlations adjusting for sex were used to analyze the relationship between RF morphology and IKDC scores. RESULTS: Injured limbs had smaller RF CSA at each time point (4.5±1.6cm2 vs 5.2±1.9cm2, p<.01 and 5.2±1.9cm2 vs 5.6±2.1 cm2, respectively) compared to the uninjured limb. Injured limb CSA increased at RTA (4.5±1.6cm2 vs 5.2±1.9cm2, p<.01) while the uninjured limb did not (p=0.12). No differences in PF were found between limbs (p=0.18, and p=0.43, respectively) or time point (p=0.67, and p=0.92, respectively). After adjusting for sex, larger injured limb CSA was associated with higher IKDC scores at 9 weeks and trended toward significance at RTA (r=0.32, p=0.05, and r=0.26, p=0.09, respectively). Injured limb PF was negatively associated with IKDC scores at both time points (r=-0.55, p=<.01, and r=-0.39, p=0.02, respectively). CONCLUSIONS: Inter-limb differences in RF muscle CSA are not ameliorated at RTA. RF CSA and PF are associated with self-reported function in individuals with ACLR and should be treatment targets to improve patient function following injury.

Early initiation of home-based sensori-motor training improves muscle strength, activation and size in patients after knee replacement: a secondary analysis of a controlled clinical trial

BackgroundThere is accumulating evidence for the advantages of rehabilitation involving sensori-motor training (SMT) following total knee replacement (TKR). However, the best way in which to deliver SMT remains elusive because of potential interference effects amongst concurrent exercise stimuli for optimal neuromuscular and morphological adaptations. The aim of this study was to use additional outcomes (i.e. muscle strength, activation and size) from a published parent study to compare the effects of early-initiated home-based rehabilitative SMT with functional exercise training (usual care) in patients undergoing TKR.MethodsA controlled clinical trial was conducted at the Orthopedic University Hospital of Rion, Greece involving allocation concealment to patients. Fifty-two patients electing to undergo TKR were randomised to either early-initiated SMT [experimental] or functional exercise training [control] in a home-based environment. Groups were prescribed equivalent duration of exercise during 12-weeks, 3–5 sessions of ~ 40 min per week of home-based programmes. Muscle strength and activation (peak force [PF]; peak amplitude [Peak Amp.] and root mean square of integrated electromyography [RMS iEMG]), muscular size (including rectus femoris muscle cross-sectional area [CSARF]), and knee ROM were assessed on three separate occasions (pre-surgery [0 weeks]; 8 weeks post-surgery; 14 weeks post-surgery).ResultsPatients undertaking SMT rehabilitation showed significantly greater improvements over the 14 weeks compared to control in outcomes including quadriceps PF (25.1 ± 18.5 N vs 12.4 ± 20.8 N); iPeak Amp. (188 ± 109.5% vs 25 ± 105.8%); CSARF (252.0 ± 101.0 mm2 vs 156.7 ± 76.2 mm2), respectively (p < 0.005); Knee ROM did not offer clinically relevant changes (p: ns) between groups over time. At 14 weeks post-surgery, the SMT group’s and control group’s performances differed by relative effect sizes (Cohen’s d) ranging between 0.64 and 1.06.ConclusionA prescribed equivalent time spent in SMT compared to usual practice, delivered within a home-based environment, elicited superior restoration of muscle strength, activation and size in patients following TKR.Trial registrationISRCTN12101643, December 2017 (retrospective registration).

Quadriceps muscle architecture ultrasonography of individuals with type 2 diabetes: Reliability and applicability.

Muscle architecture parameters performed using ultrasound serve as an aid to monitor muscle changes derived from diseases, however there are no studies that determine the reliability and applicability of this evaluation in individuals with type 2 diabetes (DM2). Three raters captured three images of measurements of thickness of the rectus femoris (RF), vastus intermedius and anterior quadriceps, RF muscle cross-sectional area, RF pennation angle in 17 individuals with DM2 above 50 and sedentary. Intra and inter-raters analysis showed reliability from high to very high for the three raters (ICC> 0.87), except for the RF pennation angle with moderate to low intra-raters (ICC = 0.58, 0.48, 0.51), and high inter-rater reliability (ICC = 0.70). Ultrasound measurements of quadriceps muscles showed high to very high intra and inter-raters reliability, thus allowing its use to monitor muscle changes provoked by diabetes or interventions in individuals with DM2.

Reliability and differences in quadriceps femoris muscle morphology using ultrasonography: The effects of body position and rest time.

The purpose of this investigation was to: (1) to determine the reliability of rectus femoris muscle cross-sectional area and echo intensity obtained using panoramic ultrasound imaging during seated and supine lying positions before and after a 5-minute rest period and (2) to determine the influence of body position and rest period on the magnitude of rectus femoris muscle cross-sectional area and echo intensity measurements. A total of 23 males and females (age = 21.5 ± 1.9 years) visited the laboratory on two separate occasions. During each visit, panoramic ultrasound images of the rectus femoris were obtained in both a seated and a supine position before (T1) and after a 5-minute (T2) rest period to quantify any potential changes in either muscle cross-sectional area and/or echo intensity. None of the muscle cross-sectional area or echo intensity measurements exhibited systematic variability, and the ICCs were 0.98-0.99 and 0.88-0.91, and the coefficients of variation were ≤ 3.9% and ≤ 8.2% for muscle cross-sectional area and echo intensity, respectively. Our results indicated that muscle cross-sectional area was greater in the seated than supine position, whereas echo intensity was greater in the supine position. Further, echo intensity increased in the seated position from T1 to T2. Both rectus femoris muscle cross-sectional area and echo intensity may be reliably measured in either a seated or supine lying position before or after a 5-minute rest period. Aside from echo intensity in the seated position, rest period had no influence on the magnitude of muscle cross-sectional area or echo intensity. Comparison of muscle cross-sectional area values that are obtained in different body positions is ill-advised.

Reliability of the rectus femoris muscle cross‐sectional area measurements by ultrasonography

The skeletal muscle system can adapt to an external stimulus from either physiological or pathological conditions. This plasticity is measured by imaging techniques such as magnetic resonance imaging or ultrasound. The anatomical cross-sectional area of a muscle is one of the muscle architecture parameters that relates to the maximum muscle strength. The aim of this study was to determine the reliability of anatomical cross-sectional area rectus femoris measurements, obtained by ultrasound, with two different protocols. Acquisition of four anatomical cross-sectional area images of the right rectus femoris in two distinct regions (15 cm above the patella and 50% of the thigh length) was performed in 2 days, from a group of 15 young healthy subjects. The cross-sectional area of each image was measured five times. The reliability of the anatomical cross-sectional area measures was determined by the coefficient of variation (CV), intraclass correlation coefficient (ICC) and typical error of measurement (TEM). In each protocol, there were no significant differences between the means of anatomical cross-sectional area in measurements, images and days (P>0·05). The CVs were 8·53% and 8·9%, the ICCs 0·88 and 0·87 and the TEMs 65·59 and 94·25 between the 2 days in the regions of 15 cm and 50% of the thigh length, respectively. The average values of the cross-sectional area at 50% of the thigh length were significantly higher than those for at 15 cm above the patella (P<0·001). The measurement of rectus femoris anatomical cross-sectional area by ultrasound proved reliable.

Ultrasound measurement of rectus femoris cross-sectional area and the relationship with quadriceps strength in COPD

Background:Quadriceps weakness and loss of muscle mass predict mortality in chronic obstructive pulmonary disease (COPD). It was hypothesised that a reduced quadriceps cross-sectional area could be detected by ultrasound in...