INTRODUCTION:Traditionally, total body (TB) dual-energy x-ray absorptiometry (DXA) scans to assess body composition include the entire body, however novel abbreviated acquisition methods exist. The purpose of this study was to evaluate comparability of measured and estimated body composition results using three novel acquisition techniques; total body less head (TBLH), neck to knee (NTK) and lower extremity (LE). We hypothesized that body composition mass with these three novel methods would not differ from traditional TB acquisition. METHODS:Each subject had TB, TBLH, NTK and LE scans acquired using a Lunar iDXA. A subset of 30 had repeat NTK and LE scans with repositioning between and a matched historical precision control was compiled from existing data for comparison. TBLH and NTK scans used automated software to limit anatomy scanned; NTK estimated non-scanned lower leg mass. LE scans were acquired from L3 to just beyond the toes. Automated analysis, with manual correction, was used for all but LE scans, which were analyzed manually. Equivalence testing was used to compare regional lean, fat and bone mineral content (BMC) measurements from the novel scanning methods to traditional full TB scans. Precision was determined by the ISCD Precision Calculator and compared to TB historical precision by F-test. RESULTS:The study sample included 82 subjects, 41F/41 M mean (SD) age 51.0 (18.4) years and BMI 25.5 (3.7) kg/m2. Total and regional lean, fat and bone mass were equivalent among all approaches (p < 0.01). There was excellent agreement between sexes and ages with TB and TBLH (p < 0.001). Some clinically irrelevant disagreement was observed in NTK and LE fat and lean measurements while NTK and LE precision was excellent, ranging from 0.45 to 2.31%CV. CONCLUSION:These three novel approaches provide regional body composition data consistent with traditional TB measurement and may be considered as equivalent substitutes when appropriate.

AbstractBackgroundEstablishing interchangeable biomedical imaging‐based measures to assess myosteatosis clinically may lead to the prevention of muscle wasting, yet neither a consensus measure nor a conversion between measures exists. Ultrasound echo intensity (EI) potentially assesses myosteatosis, but subcutaneous adipose tissue (SAT) thickness and user force application have been shown to influence EI. Although correction factors exist to adjust EI for SAT thickness, they are modelled against poor or no reference measures. Modelling EI corrections against a robust reference measure of myosteatosis, like magnetic resonance imaging (MRI)‐based proton density fat fraction (PDFF), is necessary for EI's clinical application.MethodsHealthy young adults, healthy older adults, and older adults undergoing treatment for lung cancer (n = 10 per group with 50% females) had PDFF and EI at 0, 5, 10, and 15 N measured on their right rectus femoris (RF). We compared EI, SAT thickness, and RF thickness between forces and groups and assessed the relationships between EI adjusted by four different correction factors and PDFF.ResultsThe mean age of our sample was 48.63 ± 19.68 years and had a body mass index of 25.21 ± 5.19 kg/m2. The correlation between PDFF and raw EI was r = 0.59 (P < 0.001) with negligible increases by previously published correction factors (Young: 0.62, P < 0.001; Neto Müller: 0.61, P < 0.001). EI, SAT thickness, and RF thickness did not significantly differ between forces (χ2 = 0.31, P = 0.957; χ2 = 2.39, P = 0.496; and χ2 = 7.75, P = 0.051, respectively). EI and PDFF were significantly lower among young healthy adults compared with older adult groups (χ2 = 12.88, P = 0.002, and χ2 = 9.13, P = 0.010, respectively).ConclusionsEI is correlated with PDFF regardless of force with no improvement from previously published correction factors. Our results suggest that EI is clinically useful and influenced by fat content, yet correction factors must account for more than SAT thickness alone and require further investigation.

Purpose: Intravenous contrast poses challenges to computed tomography (CT) muscle density analysis. We developed and tested corrections for contrast-enhanced CT muscle density to improve muscle analysis and the utility of CT scans for the assessment of myosteatosis. Materials and Methods: Using retrospective images from 240 adults who received routine abdominal CT imaging from March to November 2020 with weight-based iodine contrast, we obtained paraspinal muscle density measurements from noncontrast (NC), arterial, and venous-phase images. We used a calibration sample to develop 9 different mean and regression–based corrections for the effect of contrast. We applied the corrections in a validation sample and conducted equivalence testing. Results: We evaluated 140 patients (mean age 52.0 y [SD: 18.3]; 60% female) in the calibration sample and 100 patients (mean age 54.8 y [SD: 18.9]; 60% female) in the validation sample. Contrast-enhanced muscle density was higher than NC by 8.6 HU (SD: 6.2) for the arterial phase (female, 10.4 HU [SD: 5.7]; male, 6.0 HU [SD:6.0]) and by 6.4 HU [SD:8.1] for the venous phase (female, 8.0 HU [SD: 8.6]; male, 4.0 HU [SD: 6.6]). Corrected contrast-enhanced and NC muscle density was equivalent within 3 HU for all correctionns. The −7.5 HU correction, independent of sex and phase, performed well for arterial (95% CI: −0.18, 1.80 HU) and venous-phase data (95% CI: −0.88, 1.41 HU). Conclusions: Our validated correction factor of −7.5 HU renders contrast-enhanced muscle density statistically similar to NC density and is a feasible rule-of-thumb for clinicians to implement.

Lung cancer patients have low survival rates resulting in over 131,000 deaths in the US in 2021. Muscle health decline from sarcopenia and cachexia increases the risk of death among patients with lung cancer. Though muscle mass is often used for sarcopenia diagnosis and non‐tissue specific weight loss is typically used for cachexia diagnosis, both conditions have no consensus definitions. Therefore, the need for quantitative biomarkers that reflect muscle health changes due to aging and weight loss is critical to mitigate sarcopenia and cachexia. We propose using highly accurate MRI‐based proton density fat fraction (PDFF) as a reference measure of muscle health to develop bedside ultrasound measures as biomarkers of muscle health. We hypothesized that PDFF is associated with ultrasound‐based echointensity (EI) and shear wave elastography (SWE), and that all three modalities are sensitive to muscle health differences between healthy young, healthy older, and older adults undergoing treatment for lung cancer.

Computed tomography (CT) is a valuable assessment method for muscle pathologies such as sarcopenia, cachexia, and myosteatosis. However, several key underappreciated scan imaging parameters need consideration for both research and clinical use, specifically CT kilovoltage and the use of contrast material. We conducted a scoping review to assess these effects on CT muscle measures. We reviewed articles from PubMed, Scopus, and Web of Science from 1970 to 2020 on the effect of intravenous contrast material and variation in CT kilovoltage on muscle mass and density. We identified 971 articles on contrast and 277 articles on kilovoltage. The number of articles that met inclusion criteria for contrast and kilovoltage was 11 and 7, respectively. Ten studies evaluated the effect of contrast on muscle density of which nine found that contrast significantly increases CT muscle density (arterial phase 6–23% increase, venous phase 19–57% increase, and delayed phase 23–43% increase). Seven out of 10 studies evaluating the effect of contrast on muscle area found significant increases in area due to contrast (≤2.58%). Six studies evaluating kilovoltage on muscle density found that lower kilovoltage resulted in a higher muscle density (14–40% increase). One study reported a significant decrease in muscle area when reducing kilovoltage (2.9%). The use of contrast and kilovoltage variations can have dramatic effects on skeletal muscle analysis and should be considered and reported in CT muscle analysis research. These significant factors in CT skeletal muscle analysis can alter clinical and research outcomes and are therefore a barrier to clinical application unless better appreciated.

[This corrects the article DOI: 10.3389/fresc.2022.896114.].

ABSTRACTTraditional diagnostic criteria for sarcopenia use dual‐energy X‐ray absorptiometry (DXA)‐measured appendicular lean mass (ALM), normalized to height (ALM/ht2) or body mass index (ALM/BMI) to define low muscle mass. However, muscle function declines with aging before the loss of muscle mass is detected by ALM. This is likely due, in part, to qualitative muscle changes such as extracellular and intracellular fluid compartment shifts uncaptured by DXA. We propose combining bioimpedance spectroscopy (BIS), which estimates extracellular and intracellular compartment volume, with DXA to more accurately predict muscle function. This combination may help incorporate muscle quality, thereby improving sarcopenia diagnosis. We cross‐sectionally analyzed data from 248 Black and White participants aged 25 to 75 years from the Midlife in the United States Refresher Cohort. We proposed two novel muscle measures: ALM corrected by the BIS‐derived whole‐body extracellular to intracellular fluid ratio (E/I) and leg lean mass (LLM) corrected by leg‐specific E/I, creating (ALM/(E/I)W) and (LLM/(E/I)L), respectively. We compared the associations of traditional muscle measures, ALM/(E/I)W, and LLM/(E/I)L, with grip strength and lower limb power using jumping mechanography. LLM/(E/I)L explained jump power best at R2 = 0.803 compared with ALM/(E/I)W (p < 0.0001) and all other measures. ALM/(E/I)W explained jump power second best (R2 = 0.759) but not significantly better than traditional muscle measures. No muscle measure performed better than covariates when predicting handgrip strength. LLM/(E/I)L outperformed ALM/ht2 and ALM/BMI when predicting jump power. We propose LLM/(E/I)L is a powerful and clinically relevant method that accounts for muscle quality. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

This study assessed the prevalence of sexual behaviors among a nationally representative sample of Latino men and women in the United States (US) (N = 432) including Spanish language data collection. Prior studies of sexual health among US Latinos have consisted of convenience samples, and focused mainly on assessing risk behaviors. We consider a broader range of sexual behaviors, subjective sexual experiences (e.g. pleasure and arousal), and STI testing behaviors. Analyses by language dominance and gender indicate a higher variability in sexual behaviors for English-dominant participants and a link between overall STI testing to regular medical examinations, especially women. Higher rates of pleasure, orgasms and arousal was reported by Spanish-dominant men and women, relative to the English-dominant group. Results represent a nuanced examination of internal differentiation among US Latinos and provides applicable data for reducing sexual health disparities in this population.