Muscle Thickness of Anterior Mid-Thigh in Hospitalized Patients: Comparison of Supine and Standing Postures

Evaluation of Sonographic Muscle Measurement Using Established Muscle Markers

OBJECTIVES

Loss of muscle quantity and function is associated with frailty and reduced quality of life. Sonography is a simple option to quantify muscle mass, which could be included into routine diagnostic workup. This study was designed to prospectively evaluate sonographic measurement and to compare it with established measurements of muscle quantity and function.

METHODS

Between March 2020 and May 2022, 723 patients were enrolled in the study. Psoas muscle area index (PMAI) and psoas muscle thickness height index (PMTI) were quantified. Thigh muscle thickness indices (TMTI) were either measured without compression (fTMTI) or under compression (cTMTI). Variation coefficient (VC) as well as intra- and inter-observer reliability were analyzed. The reliability and reproducibility of the sonographic morphometry were assessed using two examiners. Sonographic morphometry was compared with established measurements of muscle using computed tomography and hand grip strength, respectively.

RESULTS

In 156 patients, sonographic indices were compared with corresponding CT indices. Of the 723 patients included, sonographic indices were compared with hand strength in 429 patients. Interobserver and intraobserver variability showed better results for the femur indices than for the psoas indices (correlation coefficient: 0.8697/0.9118 vs 0.7502/0.7319). Psoas muscle indices correlated best with the reference standard of the SMI. The optimal cut-off for each muscle index for determining muscle loss according to the SMI and hand grip strength was calculated.

CONCLUSION

Sonography can simplify muscle measurement and should be used in the future. Sonographic muscle indices have the potential to simplify evaluation, especially in risk groups such as patients with liver cirrhosis or other wasting disorders.

Skeletal muscle architecture and aging: A comparison of ultrasound techniques and an assessment of intrarater reliability

OBJECTIVE

To assess intrarater reliability of ultrasound-determined measurements of skeletal muscle characteristics across different measurement outcomes, imaging techniques, and age groups.

METHODS

2D ultrasound images (B-mode) of the quadriceps were obtained from young (26 ± 4 year, n = 8 M, 8 F) and older (70 ± 7 year, n = 7 M, 5 F) adults on two occasions, separated by 6 ± 3 days. With participants in both standing and supine postures, images were collected from five anatomical sites along the anterior (two sites) and lateral (three sites) compartments of the thigh corresponding to 56%, 39%, and 22% (lateral only) of femur length. Images were analysed for muscle thickness, pennation angle, and echogenicity. Intraclass correlation coefficients (ICC) were used to assess reliability.

RESULTS

Muscle thickness values were higher (p < 0.05) on images collected in the stand versus supine posture only for muscles of the anterior compartment, independent of age. Echogenicity values were higher (p < 0.05) in the vastus intermedius on images collected in the supine versus stand posture only in older adults. Pennation angle values were not impacted by imaging posture (p > 0.05). ICC values for thickness, echogenicity, and pennation angle were generally higher for analyses conducted on images collected in the supine versus stand posture. Imaging posture generated a greater difference in ICC values in the lateral versus anterior muscles and in older versus younger participants.

CONCLUSION

Our findings suggest that participant posture during imaging impacts the absolute values and intrarater reliability of ultrasound-determined muscle characteristics in a muscle-specific fashion, and this effect is greater in older compared to younger individuals.

Sonographic assessment of low muscle quantity identifies mortality risk during COVID-19: a prospective single-centre study

BACKGROUND

Assessment of muscle quantity by sonographic muscle indices could help identify patients at risk for fatal outcome during coronavirus disease-2019 (COVID-19). The aim of this study was to explore sonographic muscle indices as predictors of COVID-19 outcome and to test the feasibility of sonographic muscle measurement in an isolation context.

METHODS

Muscle indices, derived from the psoas muscle or thigh muscles, were quantified by sonography in a cohort of patients without COVID-19 to obtain reference values for low muscle quantity. Gender-specific median of different muscle indices were defined as threshold value for low muscle quantity. The prognostic relevance of low muscle quantity, was prospectively explored in two cohorts of hospitalized COVID-19 patients. Optimal muscle index cutoff values predictive for 30 day mortality during COVID-19 were determined by receiver operating characteristic-area under the curve and Youden index calculation. Muscle quantity and known prognostic factors of COVID-19 were analysed by multivariable log-regression.

RESULTS

Compared with other muscle indices, the psoas muscle area index (PMAI) showed the most favourable characteristics to predict outcome of COVID-19 disease. Sonographic morphometry of patients without COVID-19 (n = 136) revealed a gender-specific median for PMAI (male: 291.1 mm² /m² , female 260.6 mm² /m² ) as threshold value of low muscle quantity. Subsequently, COVID-19 patients (Cohort I: n = 58; Cohort II: n = 55) were prospectively assessed by bedside sonography. The studied COVID-19 patients developed a critical course of disease in 22.4% (Cohort I: n = 13/58) and 34.5% (Cohort II: n = 20/55). Mortality rate reached 12.1% (Cohort I: n = 7/58) and 20.0% (Cohort I: n = 11/55) within 30 days of follow up. COVID-19 patients with a PMAI below the gender-specific median showed a higher 30 day mortality in both COVID-19 cohorts (log rank, P < 0.05). The optimal PMAI cutoff value (206 mm² /m² ) predicted 30 day mortality of hospitalized COVID-19 patients with a sensitivity of 72% and specificity of 78.5% (receiver operating characteristic-area under the curve: 0.793, 95% confidence interval 0.671-0.914, P = 0.008). Multivariable log-regression analysis of PMAI, age, gender, BMI and comorbidities confirmed an independent association of low PMAI with 30 day mortality of COVID-19 patients (P = 0.018).

CONCLUSIONS

Sonographic morphometry provides reliable muscle quantification under hygienic precautions and allows risk stratification of patients with COVID-19.

Low-Intensity Resistance Training with Moderate Blood Flow Restriction Appears Safe and Increases Skeletal Muscle Strength and Size in Cardiovascular Surgery Patients: A Pilot Study

We examined the safety and the effects of low-intensity resistance training (RT) with moderate blood flow restriction (KAATSU RT) on muscle strength and size in patients early after cardiac surgery. Cardiac patients (age 69.6 ± 12.6 years, n = 21, M = 18) were randomly assigned to the control (n = 10) and the KAATSU RT group (n = 11). All patients had received a standard aerobic cardiac rehabilitation program. The KAATSU RT group additionally executed low-intensity leg extension and leg press exercises with moderate blood flow restriction twice a week for 3 months. RT-intensity and volume were increased gradually. We evaluated the anterior mid-thigh thickness (MTH), skeletal muscle mass index (SMI), handgrip strength, knee extensor strength, and walking speed at baseline, 5-7 days after cardiac surgery, and after 3 months. A physician monitored the electrocardiogram, rate of perceived exertion, and the color of the lower limbs during KAATSU RT. Creatine phosphokinase (CPK) and D-dimer were measured at baseline and after 3 months. There were no side effects during KAATSU RT. CPK and D-dimer were normal after 3 months. MTH, SMI, walking speed, and knee extensor strength increased after 3 months with KAATSU RT compared with baseline. Relatively low vs. high physical functioning patients tended to increase physical function more after 3 months with KAATSU RT. Low-intensity KAATSU RT as an adjuvant to standard cardiac rehabilitation can safely increase skeletal muscle strength and size in cardiovascular surgery patients.