Generalized loss of muscle mass is associated with increased morbidity and mortality in patients with cancer. The gold standard to measure muscle mass is by using computed tomography (CT). However, the aim of this prospective observational cohort study was to determine whether point-of-care ultrasound (POCUS) could be an easy-to-use, bedside measurement alternative to evaluate muscle status. Patients scheduled for major abdominal cancer surgery with a recent preoperative CT scan available were included. POCUS was used to measure the muscle thickness of mm. biceps brachii, mm. recti femoris, and mm. vasti intermedius 1 day prior to surgery. The total skeletal muscle index (SMI) was derived from patients’ abdominal CT scan at the third lumbar level. Muscle force of the upper and lower extremities was measured using a handheld dynamometer. A total of 165 patients were included (55% male; 65 ± 12 years). All POCUS measurements of muscle thickness had a statistically significant correlation with CT-derived SMI (r ≥ 0.48; p < 0.001). The strongest correlation between POCUS muscle measurements and SMI was observed when all POCUS muscle groups were added together (r = 0.73; p < 0.001). Muscle strength had a stronger correlation with POCUS-measured muscle thickness than with CT-derived SMI. To conclude, this study indicated a strong correlation between combined muscle thickness measurements performed by POCUS- and CT-derived SMI and measurements of muscle strength. These results suggest that handheld ultrasound is a valid tool for the assessment of skeletal muscle status.
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Rationale: Sarcopenia is a major problem and is common in community-dwelling elderly. In daily practice, there is need for low cost and easily assessable measurement tools to assess depletion of skeletal muscle (SM) mass, for example as one of the indicators of sarcopenia. Bio-electrical impedance analysis (BIA) is often used to estimate body composition, whereas ultrasound measurement is an upcoming and promising tool, as it is quick, easy to use and inexpensive in comparison with other tools that assess SM mass. Ultrasound could assess site-specific loss of SM mass and determine myoesteatosis. Therefore, in this pilot study we aimed to assess agreement between muscle thickness of rectus femoris (RF) by ultrasound and SM mass by BIA in an older population. Methods: Twenty-six older adults (mean± standard deviation (SD) age 64 ±5.0 y, 62% women) from the Hanze Health and Ageing Study were included. SM mass by BIA was estimated using the Janssen equation. Muscle thickness of RF was assessed by analyzing ultrasound images from the right leg. Two non-parametric tests were used for analysis. Correlation between ultrasound and BIA was assessed with Spearman Rho. Agreement was determined with Kendall’s coefficient of concordance (Kendall’s W). In both tests a score ≥ 0.7 was considered a strong correlation.Results: Mean (±SD) RF thickness was 18.9 (±3.8) mm. Median SM mass (Interquartile range) was 23.5 (20.8-34.7) kg. Correlation between RF thickness and SM mass was moderately positive (Spearman r=0.611; P = 0.001), whereas Kendall’s W showed a strong agreement (W= 0.835; P=0.002).Conclusion: Ultrasound measurement of RF showed an acceptable agreement with skeletal muscle mass assessed by BIA in our sample of older adults. Therefore, ultrasound could be a promising portable tool to estimate muscle size.
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Background & aims: Low muscle mass and -quality on ICU admission, as assessed by muscle area and -density on CT-scanning at lumbar level 3 (L3), are associated with increased mortality. However, CT-scan analysis is not feasible for standard care. Bioelectrical impedance analysis (BIA) assesses body composition by incorporating the raw measurements resistance, reactance, and phase angle in equations. Our purpose was to compare BIA- and CT-derived muscle mass, to determine whether BIA identified the patients with low skeletal muscle area on CT-scan, and to determine the relation between raw BIA and raw CT measurements. Methods: This prospective observational study included adult intensive care patients with an abdominal CT-scan. CT-scans were analysed at L3 level for skeletal muscle area (cm2) and skeletal muscle density (Hounsfield Units). Muscle area was converted to muscle mass (kg) using the Shen equation (MMCT). BIA was performed within 72 h of the CT-scan. BIA-derived muscle mass was calculated by three equations: Talluri (MMTalluri), Janssen (MMJanssen), and Kyle (MMKyle). To compare BIA- and CT-derived muscle mass correlations, bias, and limits of agreement were calculated. To test whether BIA identifies low skeletal muscle area on CT-scan, ROC-curves were constructed. Furthermore, raw BIA and CT measurements, were correlated and raw CT-measurements were compared between groups with normal and low phase angle. Results: 110 patients were included. Mean age 59 ± 17 years, mean APACHE II score 17 (11–25); 68% male. MMTalluri and MMJanssen were significantly higher (36.0 ± 9.9 kg and 31.5 ± 7.8 kg, respectively) and MMKyle significantly lower (25.2 ± 5.6 kg) than MMCT (29.2 ± 6.7 kg). For all BIA-derived muscle mass equations, a proportional bias was apparent with increasing disagreement at higher muscle mass. MMTalluri correlated strongest with CT-derived muscle mass (r = 0.834, p < 0.001) and had good discriminative capacity to identify patients with low skeletal muscle area on CT-scan (AUC: 0.919 for males; 0.912 for females). Of the raw measurements, phase angle and skeletal muscle density correlated best (r = 0.701, p < 0.001). CT-derived skeletal muscle area and -density were significantly lower in patients with low compared to normal phase angle. Conclusions: Although correlated, absolute values of BIA- and CT-derived muscle mass disagree, especially in the high muscle mass range. However, BIA and CT identified the same critically ill population with low skeletal muscle area on CT-scan. Furthermore, low phase angle corresponded to low skeletal muscle area and -density. Trial registration: ClinicalTrials.gov (NCT02555670).
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Muscle fiber-type specific expression of UCP3-protein is reported here for the firts time, using immunofluorescence microscopy
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The world population is ageing rapidly. As society ages, the incidence of physical limitations is dramatically increasing, which reduces the quality of life and increases healthcare expenditures. In western society, ~30% of the population over 55 years is confronted with moderate or severe physical limitations. These physical limitations increase the risk of falls, institutionalization, co-morbidity, and premature death. An important cause of physical limitations is the age-related loss of skeletal muscle mass, also referred to as sarcopenia. Emerging evidence, however, clearly shows that the decline in skeletal muscle mass is not the sole contributor to the decline in physical performance. For instance, the loss of muscle strength is also a strong contributor to reduced physical performance in the elderly. In addition, there is ample data to suggest that motor coordination, excitation-contraction coupling, skeletal integrity, and other factors related to the nervous, muscular, and skeletal systems are critically important for physical performance in the elderly. To better understand the loss of skeletal muscle performance with ageing, we aim to provide a broad overview on the underlying mechanisms associated with elderly skeletal muscle performance. We start with a system level discussion and continue with a discussion on the influence of lifestyle, biological, and psychosocial factors on elderly skeletal muscle performance. Developing a broad understanding of the many factors affecting elderly skeletal muscle performance has major implications for scientists, clinicians, and health professionals who are developing therapeutic interventions aiming to enhance muscle function and/or prevent mobility and physical limitations and, as such, support healthy ageing.
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OBJECTIVES: Amplitude-mode (A-mode) ultrasonography is a promising technique to monitor loss and recovery of skeletal muscle in patients with burns. However, its clinimetric properties are unknown. Therefore, we determined its feasibility, interrater, and intrarater reliability, and clinical utility.METHODS: Skeletal muscle thickness of upper arms and legs was assessed longitudinally in hospitalized adult patients with ≥ 5 % total body surface area (TBSA) burns, by pairs of two out of five raters. Feasibility was evaluated by % successful assessments, reliability by intra-class correlation coefficients (ICCs), and clinical utility by smallest detectable change (SDC).RESULTS: Thirty-four patients participated (77 % male; mean age 48 ± 17 y, median TBSA burned 12 % [IQR 7-19]). Images were acquired on 69 % of planned occasions, and 89 % of images could be analyzed. Overall interrater ICCs were ≥ 0.84 (for pairs: 0.63-0.99) and intrarater ICCs were ≥ 0.95 (for pairs: 0.45-0.99). The overall interrater SDC was ≤ 33 % of the measured mean (for pairs: 3-52 %), while intrarater SDC was ≤ 20 % (for pairs: 3-48 %). All five raters could measure legs with moderate to excellent reliability, whereas for arms some demonstrated poor reliability.CONCLUSION: A-mode ultrasonography assessment of skeletal muscle in patients with burns is feasible. However, reliability and clinical utility are rater-dependent; therefore we recommend assessments by the same rater.
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Rationale: Patients with cancer of the upper gastrointestinal tract or lung are more likely to present with malnutrition at diagnosis than, for instance, patients with melanoma. Low muscle mass is an indicator of malnutrition and can be determined by computed tomography (CT) analysis of the skeletal muscle index (SMI) at the 3rd lumbar vertebra (L3) level. However, CT images at L3 are not always available. At each vertebra level, we determined if type of cancer, i.e., head and neck cancer (HNC), oesophageal cancer (OC) or lung cancer (LC) vs. melanoma (ME) was associated with lower SMI. Methods: CT images from adult patients with HNC, OC, LC or ME were included and analyzed. Scans were performed in the patient’s initial staging after diagnosis. MIM software version 7.0.1 was used to contour the muscle areas for all vertebra levels. Skeletal muscle area was corrected for stature to calculate SMI (cm2/m2). We tested for the association of HNC, OC, or LC diagnosis vs ME with SMI by univariate and multivariate linear regression analyses. In the multivariate analyses, age (years), sex, and body mass index (BMI; kg/m2) were included. Betas (B;95%CI) were calculated and statistical significance was set at p
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BACKGROUND & AIMS: We studied whether low pre-treatment muscle mass, measured with CT at thoracic (T4) or lumbar level (L3) associates with early termination of chemotherapy related to toxicity in head and neck cancer (HNC) patients.METHODS: This was a retrospective chart and image review. Adult HNC patients treated with (surgery and) platinum-based chemo-radiotherapy were included if a pre-treatment CT scan at T4 or L3 level was available. Muscle mass was evaluated by assessment of skeletal muscle index (SMI; cm2/m2). T4 and L3 SMI measurements were corrected for deviation from their respective means and were merged into one score for SMI difference (cm2/m2). All cases were assessed for presence of toxicity-related unplanned early termination of chemotherapy ('early termination'). Univariate and multivariate logistic regression models were used to investigate associations between pooled SMI and early termination.RESULTS: 213 patients (age: 57.9 ± 10.3 y, male: 77%, T4 image: 45%) were included. A significant association between SMI as a continuous variable and early termination was found, both in the univariate analysis (p = 0.007, OR = 0.96 [0.94-0.99]) and the multivariate analysis (p = 0.021, OR 0.96 [0.92-0.99]). The multivariate models identified potential associations with type of chemotherapy, presence of co-morbidity, a combination of (former) smoking and alcohol consumption, and sex.CONCLUSION: Lower muscle mass was robustly associated with higher odds of early termination of chemotherapy in HNC patients. Further prospective studies are required to tailor the care for patients with low muscle mass and to avoid early termination of chemotherapy.
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OBJECTIVES: Assessment of malnutrition-related muscle depletion with computed tomography (CT) using skeletal muscle index (SMI) and muscle radiation attenuation (MRA) at the third lumbar vertebra is well validated. However, SMI and MRA values at other vertebral locations and interchangeability as parameters in different types of cancer are less known. We aimed to investigate whether adult patients with different types of cancer show differences in SMI and MRA at all vertebral levels.METHODS: We retrospectively analyzed CT images from 203 patients:120 with head and neck cancer, esophageal cancer, or lung cancer (HNC/EC/LC) and 83 with melanoma (ME). Univariate and multivariate linear regression analyses determined the association between SMI (cm²/m 2) and MRA (Hounsfield units) and cancer type at each vertebral level (significance corrected for multiple tests, P ≤ 0.002). The multivariate analyses included age, sex, cancer stage, comorbidity, CT protocol, and body mass index (BMI) (MRA analyses). RESULTS: SMI was lower in the HNC/EC/LC group versus the ME group at all vertebral levels, except C4 through C6 in the multivariate analyses. Female sex was associated with lower SMI at almost all levels. MRA was similar at most vertebral levels in both cancer groups but was lower at C1 through C4, T7, and L5 in the multivariate analyses. Use of contrast fluid and BMI were associated with higher MRA at all vertebral levels except T8 to T9 and C1 to C2, respectively.CONCLUSIONS: SMI, but not MRA, was lower in HNC/EC/LC patients than in ME patients at most vertebral levels. This indicates that low muscle mass presents itself across the various vertebral muscle areas. MRA may less consistently mark muscle depletion in malnourished patients.
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BACKGROUND: Muscle quantity at intensive care unit (ICU) admission has been independently associated with mortality. In addition to quantity, muscle quality may be important for survival. Muscle quality is influenced by fatty infiltration or myosteatosis, which can be assessed on computed tomography (CT) scans by analysing skeletal muscle density (SMD) and the amount of intermuscular adipose tissue (IMAT). We investigated whether CT-derived low skeletal muscle quality at ICU admission is independently associated with 6-month mortality and other clinical outcomes.METHODS: This retrospective study included 491 mechanically ventilated critically ill adult patients with a CT scan of the abdomen made 1 day before to 4 days after ICU admission. Cox regression analysis was used to determine the association between SMD or IMAT and 6-month mortality, with adjustments for Acute Physiological, Age, and Chronic Health Evaluation (APACHE) II score, body mass index (BMI), and skeletal muscle area. Logistic and linear regression analyses were used for other clinical outcomes.RESULTS: Mean APACHE II score was 24 ± 8 and 6-month mortality was 35.6%. Non-survivors had a lower SMD (25.1 vs. 31.4 Hounsfield Units (HU); p < 0.001), and more IMAT (17.1 vs. 13.3 cm(2); p = 0.004). Higher SMD was associated with a lower 6-month mortality (hazard ratio (HR) per 10 HU, 0.640; 95% confidence interval (CI), 0.552-0.742; p < 0.001), and also after correction for APACHE II score, BMI, and skeletal muscle area (HR, 0.774; 95% CI, 0.643-0.931; p = 0.006). Higher IMAT was not significantly associated with higher 6-month mortality after adjustment for confounders. A 10 HU increase in SMD was associated with a 14% shorter hospital length of stay.CONCLUSIONS: Low skeletal muscle quality at ICU admission, as assessed by CT-derived skeletal muscle density, is independently associated with higher 6-month mortality in mechanically ventilated patients. Thus, muscle quality as well as muscle quantity are prognostic factors in the ICU.TRIAL REGISTRATION: Retrospectively registered (initial release on 06/23/2016) at ClinicalTrials.gov: NCT02817646 .
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