Modular and Portable System Design for 3D Imaging of Breast Tumors Using Electrical Impedance Tomography.

This paper presents a prototype of a portable and modular electrical impedance tomography (EIT) system for breast tumor detection. The proposed system uses MATLAB to generate three-dimensional representations of breast tissue. The modular architecture of the system allows for flexible customization and scalability. It consists of several interconnected modules. Each module can be easily replaced or upgraded, facilitating system maintenance and future enhancements. Testing of the prototype has shown promising results in preliminary screening based on experimental studies. Agar models were used for the experimental stage of this project. The 3D representations provide clinicians with valuable information for accurate diagnosis and treatment planning. Further research and refinement of the system is warranted to validate its performance in future clinical trials.

Effect of Oral Zinc Supplementation on Phase Angle and Bioelectrical Impedance Vector Analysis in Duchenne Muscular Dystrophy: A Non-Randomized Clinical Trial.

Zinc plays a crucial role in cell structure and functionality. Neurodegenerative Duchenne muscular dystrophy (DMD) alters muscle membrane structure, leading to a loss of muscle mass and strength. The objective of this study was to evaluate the changes in phase angle (PA) and bioelectrical impedance vector analysis (BIVA) results in patients with DMD after oral zinc supplementation. This clinical trial included 33 boys aged 5.6 to 24.5 years diagnosed with DMD. They were divided into three groups according to age (G1, G2, and G3) and supplemented with oral zinc. The mean serum zinc concentration was 74 µg/dL, and 29% of patients had concentrations below the reference value. The baseline values (mean (standard deviation)) of the bioelectrical impedance parameters PA, resistance (R), and reactance (Xc) were 2.59° (0.84°), 924.36 (212.31) Ω, and 39.64 (8.41) Ω, respectively. An increase in R and a decrease in PA and lean mass proportional to age were observed, along with a negative correlation (r = -0.614; p < 0.001) between age and PA. The average cell mass in G1 was greater than that in G3 (p = 0.012). There were no significant differences in serum zinc levels or bioelectrical impedance parameters before and after zinc supplementation. We conclude that this population is at risk of zinc deficiency and the proposed dosage of zinc supplementation was not sufficient to alter serum zinc levels, PA and BIVA results.

Ex vivo electrical bioimpedance measurements and Cole modelling on the porcine colon and rectum.

Different pathological changes in the large intestine wall, associated with the development of different chronic diseases, including colorectal cancer, could be reflected in electrical bioimpedance readings. Thickness and composition of the mucus bilayer covering it in the luminal side, abundance of bacteria of the intestinal microbiota, the permeability of the epithelium and inflammation are some of these. However, scientific literature on electrical passive properties of the large intestine is scarce. In this study, complex impedance measurements at 8 frequencies were carried out on 6 specimens of porcine colorectal tissue, within half ab hour post-mortem, obtained from a local abattoir. For 5 different distances, measured proximally from the border of the anus, 3 readings were taken at 3 different points with a tetrapolar probe. The results show 2 different dielectric dispersions in the α and ß regions and it seems that there is a relationship between the values of resistivities and the thickness of the wall. Also, parameter values both for the Cole and the geometrical models are given. Another set of electrical bioimpedance readings was carried out in order to assess the effect of the mucus layer on electrical properties of the tissue. It seems that these layers are related to the low frequency dispersion. Finally, electrical passive properties of porcine colorectal tissue, reported in this work, give reference values and behaviour patterns that could be applied for further research in human medicine, based on bioimpedance measurements.

Utilidad de la tomografía de impedancia eléctrica para la programación del ventilador mecánico en paciente crítico pediátrico, una alternativa dinámica y no invasiva: revisión de dos casos clínicos / Utility of electrical impedance tomography for mechanical ventilator programming in pediatric critical patients, a dynamic and non-invasive alternative: a review of two clinical cases

La tomografía por impedancia eléctrica (TIE) es una modalidad de monitorización funcional respiratoria por imagen, no invasiva y libre de radiación, que permite visualizar en tiempo real la ventilación pulmonar regional y global en pacientes adultos y pediátricos conectados a Ventilación Mecánica (VM). OBJETIVO: Se describe la utilidad de la TIE en dos pacientes críticos pediátricos, en quienes no fue factible realizar medición de mecánica pulmonar, como herramienta para el ajuste de parámetros ventilatorios. CASOS CLÍNICOS: Se presentan dos pacientes pediátricos de 27 y 11 meses con condiciones clínicas diferentes, conectados a VM, en quienes se utilizó la TIE como método de monitoreo de la distribución pulmonar y titulación de la presión positiva al final de la espiración (PEEP) óptima, con el objetivo de obtener una ventilación pulmonar más homogénea. Se presentan mediciones funcionales con diferentes niveles de PEEP y valores de distribución en las distintas regiones de interés (ROI), además de un flujograma de situaciones en las que la TIE podría resultar útil para el ajuste ventilatorio. CONCLUSIÓN: La información funcional proporcionada por la TIE, permitió monitorizar de forma dinámica la VM y optimizar los parámetros ventilatorios, facilitando la implementación de estrategias de protección pulmonar en ambos pacientes, imposibilitados de realizar una medición estática de la mecánica respiratoria.

The Electrical Impedance Tomography (EIT) is a non-invasive and radiation-free respiratory functional imaging monitoring modality that allows real-time visualization of regional and global lung ventilation in adult and pediatric patients connected to mechanical ventilation (MV). OBJECTIVE: This paper describes the utility of EIT in two critical pediatric patients for whom measuring pulmonary mechanics was not feasible. EIT is used as a tool for adjusting ventilatory parameters. CLINICAL CASES: Two pediatric patients aged 27 and 11 months, with different clinical conditions, connected to MV are presented. EIT was used to monitor lung distribution and titrate the optimal Positive End-Expiratory Pressure (PEEP), to achieve more homogeneous lung ventilation. Functional measurements are presented with different PEEP levels and distribution values in different regions of interest (ROI), along with a flowchart illustrating situations where EIT could be useful for ventilatory adjustment. CONCLUSION: The functional information provided by EIT, allowed dynamic monitoring of MV, optimizing ventilatory parameters and facilitating the implementation of lung protective strategies in both patients, unable to undergo static respiratory mechanics measurements.

Phase angle as a potential tool to evaluate chronic inflammatory state and predict quality of life deterioration in women with breast cancer and obesity: A narrative review.

The interaction between lifestyle--defined more specifically in health care as the personal exposome--and its implications on obesity and breast cancer development highlights the critical role of body composition and inflammation in these patients. There is clear evidence that the personal and internal exposome triggers biochemical, inflammatory, and metabolic reprogramming, which might favor ectopic lipid accumulation within the body, such as muscles. Additionally, the presence of excessive adipose tissue exacerbates these alterations in the internal exposome, resulting in cell damage and modifying body composition. Understanding the nexus between these lifestyle-induced exposome modifications, such as inflammation, and the resultant changes in body composition is crucial to assess the association with breast cancer progression and treatment responses. Various techniques can be used to evaluate body composition; one of those most used currently is bioelectrical impedance analysis. This analysis provides parameters, including phase angle (PhA), by which cellular health and metabolic activity can be assessed. In addition, PhA is a potential indicator of nutritional status and disease prognosis, as it has been linked to survival and quality of life in patients with cancer. Therefore, PhA might be used in daily oncology practice to implement an accurate nutritional intervention, reducing side effects and complications of oncology management, and improving quality of life during treatment and survival, even in patients with breast cancer with obesity or overweight. The aim of this review is to analyze the existing information on the current application of PhA in patients with breast cancer and its potential use as a tool to assess inflammatory response, identify malnutrition, and predict the deterioration of quality of life so that it could be proposed as an early indicator for nutritional interventions in this group of patients.

Association between muscle-localized bioelectrical impedance analysis parameters and performance in a multi-set exercise on the isokinetic dynamometer in young women.

This study aimed to verify the relationship between changes in thigh muscle-localized bioelectrical impedance analysis (ML-BIA) parameters and performance in a multiple-set exercise. The sample consisted of 30 female university students (22.1 ± 3.2 years). The ML-BIA parameters, including localized muscle resistance (ML-R), reactance (ML-Xc), and phase angle (ML-AngF), were evaluated using a tetrapolar bioelectric impedance device operating at a frequency of 50 KHz. The multiple sets protocol was performed with an isokinetic dynamometer. For body composition, total and leg lean soft tissue (LST) were evaluated using dual X-ray absortiometry. Student's t-test for paired samples was used to compare the ML-BIA parameters and thigh circumference pre and postexercise. Linear regression analysis was performed to verify the ∆ML-PhA as a predictor of peak torque for the three sets alone while controlling for total and leg LST. There were differences in the ML-R (∆ = 0.02 ± 1.45 Ω; p = 0.001; and E.S = 0.19), ML-Xc (∆ = 2.90 ± 4.12 Ω; p = 0.043; and E.S = 0.36), and thigh circumference (∆ = 0.82 ± 0.60 cm; p < 0.001; and E.S = 0.16) pre- and post-multiple sets. ΔML-PhA was a predictor of performance in the first set (p = 0.002), regardless of total and leg LST. However, the ΔML-PhA lost its explanatory power in the other sets (second and third), and the variables that best explained performance were total and leg LST. The ML-BIA (ML-R and ML-Xc) parameters were sensitive and changed after the multiple sets protocol, and the ΔML-PhA was a predictor of performance in the first set regardless of the total and leg LST.

Body Composition Classification with Electrical Bioimpedance in Chilean Military by Sex / Clasificación de la Composición Corporal con Bioimpedancia Eléctrica en Militares Chilenos por Sexo

SUMMARY: Military readiness relies heavily on the physical fitness and operational capability of its personnel. This study aims to enhance the effectiveness of body composition assessment and classification protocols within the military context. A comprehensive evaluation of 4370 active-duty Chilean military personnel was conducted, focusing on anthropometric characteristics, including adipose tissue, muscle tissue, and anthropometric indices. The study observed significant differences in body composition between genders, with men exhibiting lower levels of body fat percentage (men: 26.28 %; women: 34.62 %) but higher levels of muscle mass (men: 42.0 %; women: 36.0 %;), skeletal muscle index (men:11.81; women: 9.31), and fat-free mass index (men: 19.92; women: 18.45) compared to women. High levels of muscle tissue were observed in both groups. By integrating these findings into a standardized assessment protocol, a more accurate classification of military personnel was achieved, surpassing traditional methods used in sedentary obese populations. The study advocates the future adoption of an assessment model based on artificial intelligence (AI) algorithms, which consider the multifaceted nature of body composition and its impact on operational capability. Such a model would enable military forces to optimize their personnel's physical fitness and readiness, thus enhancing their effectiveness in deployment operations.

La preparación militar depende en gran medida de la aptitud física y la capacidad operativa de su personal. Este estudio tiene como objetivo mejorar la eficacia de los protocolos de evaluación y clasificación de la composición corporal dentro del contexto militar. Se realizó una evaluación integral de 4.370 militares chilenos en servicio activo, centrándose en las características antropométricas, incluido el tejido adiposo, el tejido muscular y los índices antropométricos. El estudio observó diferencias significativas en la composición corporal entre sexos, con los hombres exhibiendo niveles más bajos de porcentaje de grasa corporal (hombres: 26,28 %; mujeres: 34,62 %) pero niveles más altos de masa muscular (hombres: 42,0 %; mujeres: 36,0 %;), índice de músculo esquelético (hombres: 11,81; mujeres: 9,31) e índice de masa magra (hombres: 19,92; mujeres: 18,45) en comparación con las mujeres. Se observaron altos niveles de tejido muscular en ambos grupos. Al integrar estos hallazgos en un protocolo de evaluación estandarizado, se logró una clasificación más precisa del personal militar, superando los métodos tradicionales utilizados en poblaciones obesas sedentarias. El estudio aboga por la adopción futura de un modelo de evaluación basado en algoritmos de inteligencia artificial (IA), que consideren la naturaleza multifacética de la composición corporal y su impacto en la capacidad operativa. Un modelo de este tipo permitiría a las fuerzas militares optimizar la aptitud física y la preparación de su personal, mejorando así su eficacia en las operaciones de despliegue.

Correlación del Ángulo de Fase con las Masas Muscular y Grasa en una Población Caucásica Sana de Amplio Rango de Edad / Correlation of Phase Angle with Muscle and Fat Mass in a Healthy Caucasian Population of a Wide Age Range

El análisis de impedancia bioeléctrica (BIA) es un método relativamente económico, rápido y no invasivo para la determinación de la composición corporal. El ángulo de fase (PhA) es un indicador de la salud celular y de la integridad de la membrana y parece estar relacionado con la capacidad física y el rendimiento deportivo. El objetivo de este estudio fue el de analizar las posibles relaciones entre PhA y el porcentaje de masa muscular esquelética (SMM%) y entre PhA y el porcentaje de masa grasa (FM%) en una población caucásica sana, con un amplio rango de edad. Se analizaron 210 sujetos caucásicos sanos (99 mujeres y 111 hombres), de edades comprendidas entre 20 y 70 años. Se utilizó un dispositivo BIA mano-pie (BIA-101, AKERN-Srl, Firenze, Italy) para la determinación de los parámetros bioeléctricos y un escáner DXA de cuerpo entero QDR, serie Horizon (Hologic Inc., Bedford, MA, USA) para la determinación de SMM% y FM%. Se observaron correlaciones significativas positivas fuertes entre PhA y SMM%, independientemente de la franja de edad, (0,520-0,687; p < 0,01) y correlaciones significativas negativas fuertes (o moderadas/fuertes) entre PhA y FM% (0,492-0,657; p < 0,01), también independientemente de la franja de edad. Estas correlaciones indican que PhA podría utilizarse como marcador para ver la evolución de un sujeto activo, sea deportista o no. Se recomienda, por tanto, el desarrollo y la validación de nuevas ecuaciones para determinar la masa muscular y la masa grasa, que incluyan PhA como parámetro bioeléctrico.

SUMMARY: Bioelectrical impedance analysis (BIA) is a non-invasive, economic and fast method for body composition assessment. Phase angle (PhA) is considered an indicator of cellular health and cell membrane integrity, and it seems to be related to physical capacity and performance. The aim of this study was to analyze the possible relationships between PhA and skeletal muscle mass percentage (SMM%) and between PhA and fat mass percentage (FM%) in a healthy Caucasian population with a wide age range. 210 healthy Caucasian participants (99 women and 111 men), aged 20-70 years were analyzed. A BIA foot-to-hand body composition analyzer (BIA-101, AKERN-Srl, Firenze, Italy) was used to determine bioelectrical parameters, and a whole body DXA scanner QDR, serie Horizon (Hologic Inc., Bedford, MA, USA) was used for SMM% and FM% assessment. Irrespective of age range, strong positive significant correlations were observed between PhA and SMM% (0.520-0.687; p < 0.01) and strong (or moderate/strong) negative significant correlations were observed between PhA and FM% (0.492-0.657; p < 0.01). These correlations indicate that PhA could be used as a marker to monitor the evolution of an active subject, whether an athlete or not. It would be useful to develop and validate new equations for skeletal muscle mass and fat mass assessment, which include PhA as a bioelectrical parameter.

Comparison between Measured and Predicted Resting Metabolic Rate Equations in Cross-Training Practitioners.

This study aimed to investigate the resting metabolic rate (RMR) in cross-training practitioners (advanced and novice) using indirect calorimetry (IC) and compare it with predictive equations proposed in the scientific literature. METHODS: A cross-sectional and comparative study analyzed 65 volunteers, both sexes, practicing cross-training (CT). Anthropometry and body composition were assessed, and RMR was measured by IC (FitMate PRO®), bioimpedance (BIA-InBody 570®), and six predictive equations. Data normality was tested by the Kolgomorov-Smirnov test and expressed as mean ± standard deviation with 95% confidence intervals (CI), chi-square test was performed to verify ergogenic resources, and a Bland-Altman plot (B&A) was made to quantify the agreement between two quantitative measurements. One-way ANOVA was applied to body composition parameters, two-way ANOVA with Bonferroni post hoc was used to compare the RMR between groups, and two-way ANCOVA was used to analyze the adjusted RMR for body and skeletal muscle mass. The effect size was determined using Cohen's d considering the values adjusted by ANCOVA. If a statistical difference was found, post hoc Bonferroni was applied. The significance level was p < 0.05 for all tests. RESULTS: The main results indicated that men showed a higher RMR than women, and the most discrepant equations were Cunningham, Tinsley (b), and Johnstone compared to IC. Tinsley's (a) equation indicated greater precision in measuring the RMR in CM overestimated it by only 1.9%, and BIA and the Harris-Benedict in CW overestimated RMR by only 0.1% and 3.4%, respectively. CONCLUSIONS: The BIA and Harris-Benedict equation could be used reliably to measure the RMR of females, while Tinsley (a) is the most reliable method to measure the RMR of males when measuring with IC is unavailable. By knowing which RMR equations are closest to the gold standard, these professionals can prescribe a more assertive diet, training, or ergogenic resources. An assertive prescription increases performance and can reduce possible deleterious effects, maximizing physical sports performance.

[Experience with endoluminal functional luminal probe (EndoFLIP) at San Ignacio University Hospital, Bogota, Colombia]. / Experiencia con sonda luminal funcional endoluminal (EndoFLIP) en Hospital Universitario San Ignacio, Bogotá, Colombia.

INTRODUCTION: The EndoFLIP (for its acronym in English: endoluminal functional luminal probe) is a system that measures in real time the compliance index of the gastroesophageal junction and secondary esophageal peristalsis, based on the principle of impedance planimetry. Although this technology is relatively new and its diagnostic usefulness is still being evaluated, its use in clinical practice is increasingly recognized, fundamentally in those patients where there is no conclusive manometric diagnosis of esophageal motor pathology, mainly esophagogastric junction outflow obstruction and achalasia. OBJECTIVE: The aim of the present study is to describe the experience with EndoFLIP at the San Ignacio University Hospital in Bogotá, Colombia. MATERIAL AND METHODS: Descriptive observational case series study, which included patients over 18 years of age who had undergone EndoFLIP at the San Ignacio University Hospital from 2021 to 2022, either in-hospital or outpatient, with a clear indication of performance of the study, previously discussed in the multidisciplinary Gastroenterology Board. RESULTS: A total of 27 patients with an average age of 55 years were included in the study, of which 20 were women (74%) and 7 men (26%). The most frequent indication of the study was an inconclusive diagnosis of outflow tract obstruction identified in high-resolution esophageal manometry according to Chicago 4.0 criteria (14 patients), followed by hypercontractile esophagus (4 patients) and ineffective esophageal motility (3 patients). When evaluating the contractile response, it was found that 9 patients with an inconclusive diagnosis of outflow tract obstruction had a normal response, 3 absent and one altered; and in the patients with an inconclusive diagnosis of achalasia, one of them had a borderline contractile response and two had no response. All patients with a previous diagnosis of absent contractility had an equally absent contractile response in EndoFLIP. CONCLUSION: Endoluminal functional luminal imaging is a technique that evaluates biomechanical properties such as distensibility, volume, pressure and even diameters of sphincter regions such as the gastroesophageal junction, pylorus and anus. Its usefulness has been highlighted for several indications, the most important being manometrically inconclusive diagnoses of esophageal motor disorders such as achalasia and outflow tract obstruction, pathologies that have a significant impact on the quality of life of patients and whose diagnosis is essential to be able to provide the best treatment option.

First real-time imaging of bronchoscopic lung volume reduction by electrical impedance tomography.

BACKGROUND: Bronchoscopic lung volume reduction (BLVR) with one-way endobronchial valves (EBV) has better outcomes when the target lobe has poor collateral ventilation, resulting in complete lobe atelectasis. High-inspired oxygen fraction (FIO2) promotes atelectasis through faster gas absorption after airway occlusion, but its application during BLVR with EBV has been poorly understood. We aimed to investigate the real-time effects of FIO2 on regional lung volumes and regional ventilation/perfusion by electrical impedance tomography (EIT) during BLVR with EBV. METHODS: Six piglets were submitted to left lower lobe occlusion by a balloon-catheter and EBV valves with FIO2 0.5 and 1.0. Regional end-expiratory lung impedances (EELI) and regional ventilation/perfusion were monitored. Local pocket pressure measurements were obtained (balloon occlusion method). One animal underwent simultaneous acquisitions of computed tomography (CT) and EIT. Regions-of-interest (ROIs) were right and left hemithoraces. RESULTS: Following balloon occlusion, a steep decrease in left ROI-EELI with FIO2 1.0 occurred, 3-fold greater than with 0.5 (p < 0.001). Higher FIO2 also enhanced the final volume reduction (ROI-EELI) achieved by each valve (p < 0.01). CT analysis confirmed the denser atelectasis and greater volume reduction achieved by higher FIO2 (1.0) during balloon occlusion or during valve placement. CT and pocket pressure data agreed well with EIT findings, indicating greater strain redistribution with higher FIO2. CONCLUSIONS: EIT demonstrated in real-time a faster and more complete volume reduction in the occluded lung regions under high FIO2 (1.0), as compared to 0.5. Immediate changes in the ventilation and perfusion of ipsilateral non-target lung regions were also detected, providing better estimates of the full impact of each valve in place. TRIAL REGISTRATION: Not applicable.

Phase Angle and Body Composition as Predictors of Fitness and Athletic Performance in Adolescent Boxers.

BACKGROUND: Phase angle (PhA) is an indicator of cellular health, function, and integrity. PhA has been considered an indicator of nutritional and health status, but it is uncertain whether it could be used as a fitness or athletic performance indicator. OBJECTIVE: To analyze the relationship between PhA and the fitness and athletic performance of adolescent boxers and to know whether this association is independent of body composition. METHODS: Thirty-seven trained youth boxers (15-18 y old) participated in the study. Participants underwent anthropometry and bioelectrical impedance assessments. The following tests were conducted: Fitness-Gram battery; speed, agility, and quickness; ball throws; punch impact force; bench press maximal strength; and vertical and horizontal jumps. Linear regression models were estimated and adjusted by covariates. RESULTS: The PhA was related to upper-limb strength. Nevertheless, in linear regression models, after adjusting models by body composition, only PhA remained as a predictor of relative maximal strength. The PhA was not a predictor of speed, agility, and quickness; cardiorespiratory fitness; or lower-limb power, in which adiposity was the main predictor of fitness. CONCLUSIONS: In adolescent boxers, PhA can predict upper-limb maximal strength independently of bioelectrical impedance analysis premises. However, compared with mucle mass, PhA is not a better predictor of upper-limb maximal strength.

Postural balance and functional mobility in relation to BMI and body composition among female students at a College of Applied Medical Sciences: A cross-sectional study.

INTRODUCTION: This study aimed to compare different Body Mass Index (BMI) categories, body composition parameters, postural balance, and functional mobility among female students at a College of Applied Medical Sciences; and examine the relationship between BMI and body composition with postural balance and functional mobility among female students at the college of applied medical sciences. MATERIALS AND METHODS: Female students, aged 18‒25 years old. They were subdivided into four groups according to their BMI category: underweight, normal, overweight, or obese, with n = 20 participants in each group. A Bioelectrical Impedance Human Body Analyzer (BIA) was used to assess the following body composition parameters: Fat Percentage (FATP), fat mass, muscle mass, and Total Body Water (TBW). A NeuroCom Balance Master was used to assess postural balance and functional mobility. A Timed Up and Go (TUG) test was employed to assess functional mobility. All data were analyzed using SPSS. RESULTS: Participants' ages and heights were matched (p > 0.05). However, there were variables that were statistically significantly higher in terms of weight, BMI and body composition, including FATP, fat mass, muscle mass, and TBW (p = 0.000), among the obese group. Moreover, postural balance was lower among the obese group. There was a significant relationship between BMI and body composition variables in respect of postural balance but not in relation to functional mobility. CONCLUSION: Postural instability but not functional mobility was related to higher BMI and body composition values among the study groups.

Phase angle and its determinants among adolescents: influence of body composition and physical fitness level.

To examine the association between levels of physical fitness, parameters of body composition and phase angle (PhA) amongst adolescents. A total of 152 adolescents (84 girls) aged 11-16 years were included in this study. Weight and height were measured and the body mass index (BMI) was calculated. Bioelectrical impedance analysis (BIA) provided resistance and reactance parameters to calculate fat-free mass (FFM), PhA and fat mass (%FM). The following physical fitness variables were analysed: flexibility, abdominal muscular endurance, upper and lower limb explosive strength, agility, speed and cardiorespiratory fitness. Generalized Linear Models were applied to verify differences across sexes. Stepwise linear regression was used to establish an association between the variables studied. The study established an association between PhA and weight, FFM, BMI, FM, %FM and medicine ball throw (MBT) for girls. As for the boys, an association was verified between PhA and weight, FFM, BMI, standing long jump (SLJ), MBT and the three allometric VO2peak variables analyzed. An association was found between PhA and the boys' 4-m shuttle run test (4SRT) and 20-m sprint test (20SRT). Boys showed a greater phase angle than girls; In girls, BMI and %FM, were determinant of 32.4% (r = 0.57). PhA variability which is influenced by physical fitness, body composition and, therefore, the tissues electrical conductivity. Furthermore, boys' height, FFM, upper limb strength, and agility account for 58.4% (r = 0.76) PhA variability. There was a positive correlation between the physical fitness tests and the PhA.

Associations of upper- and lower-limb muscle strength, mass, and quality with health-related quality of life in community-dwelling older adults.

AIM: This study aimed to investigate the associations between upper- and lower-limb muscle strength, mass, and quality and health-related quality of life (HRQoL) among community-dwelling older adults. METHODS: A cross-sectional study was conducted with 428 Brazilian community-dwelling older adults aged 60 to 80 years. Upper- and lower-limb muscle strength were evaluated through the handgrip strength (HGS) test and the 30-s chair stand test, respectively. Muscle mass was assessed by dual-energy X-ray absorptiometry (DXA) and bioelectrical impedance analysis (BIA). Muscle quality was evaluated using the muscle quality index (MQI). HRQoL was assessed using the World Health Organization Quality of Life Brief Version questionnaire. RESULTS: Lower-limb, but not upper-limb, muscle strength and quality were independently associated with HRQoL, particularly within the domains of physical capacity, environment, and overall HRQoL for both males and females (P < 0.05). DXA- and BIA-derived analyses provided similar results in relation to muscle mass and muscle quality. CONCLUSIONS: Lower-limb, but not upper-limb, muscle strength and quality were independently associated with HRQoL among community-dwelling older adults. Moreover, the results obtained from both BIA and DXA were similar, highlighting that BIA can serve as a viable surrogate method for estimating body composition in resource-limited clinical settings. Geriatr Gerontol Int 2024; 24: 683-692.

Evaluating Dielectric Properties for Assessing Water Content at Acupuncture Points: New Methodology.

Importance: Understanding acupuncture point microenvironments is vital for optimizing treatment efficacy. Evaluating changes in water content at these points can provide further insights into the effects of acupuncture on tissues. Objective: This study aimed to measure tissue dielectric constant (TDC) and assess changes in water content, specifically at stomach 36 (ST36, Zusanli) and spleen 6 (SP6, Sanyinjiao) acupuncture points. Methods: In a controlled, blinded, randomized trial, 113 healthy volunteers were divided into six groups based on TDC sensor diameters (XS, M, and L): three control groups and three acupuncture groups. They were assessed at three time points: T1, baseline; T2, 20 min post-needle withdrawal; and T3, 40 min post-needle withdrawal. Electrical impedance (EI) was also analyzed. Significance level was set at p < 0.001. Results: TDC at ST36 and SP6 significantly decreased with the XS probe at T2 and T3 compared with that at T1 (F8, 452: 54.61). TDC did not significantly vary between T2 and T3 with M and L probes. EI data indicated that the current passage increased in the SP (F2, 226: 39.32) and ST (F2, 226: 37.32) groups during T2 and T3 compared with that during T1 within their respective groups and controls. Conclusions: and Relevance: This study demonstrated the efficacy of TDC measurements in detecting water content fluctuations at acupuncture points and their responses to needles. TDC measurements, which were validated against EI, provide valuable insights into acupuncture point microenvironments and thus help optimize treatments.

A new formula proposal for placing pH-impedance catheters in pediatric patients.

INTRODUCTION: Esophageal pH-impedance monitoring is a tool for diagnosing gastroesophageal reflux in children. The position of the pH catheter is essential for a reliable reading and the current formulas for calculating catheter insertion length are not completely accurate. The aim of the present study was to develop a new formula for adequate insertion of the pH catheter. MATERIAL AND METHODS: A cross-sectional study was conducted on children that underwent pH-impedance monitoring and later radiographic control, to calculate the correct catheter insertion length. The documented variables were age, sex, weight, height, naris to tragus distance, tragus to sternal notch distance, sternal notch to xiphoid process distance, and initial insertion length determined by the Strobel and height interval formulas. A multivariate regression analysis was carried out to predict the final insertion length. Regression ANOVA and Pearson's adjusted R-squared tests were performed. RESULTS: Forty-five pH-impedance studies were carried out, 53% of which were in males. The age and weight variables were not normally distributed. In the initial regression model, the variables that did not significantly correlate with the final insertion length were: sex (P 0.124), length determined by the Strobel or height interval formulas (P 0.078), naris to tragus distance (P 0.905), and tragus to sternal notch distance (P 0.404). The final equation: 5.6 + (height in cm * 0.12) + (sternal notch to xiphoid process distance * 0.57) produced an R2 of 0.93 (P 0.000). CONCLUSIONS: This formula can be considered a valid option for placement of the pH-impedance monitoring catheter in pediatrics.

Fat-free mass predictive equation using multifrequency bioelectrical impedance data in adolescent soccer athletes: development and cross-validation.

OBJECTIVES: This study aimed to develop and cross-validate a fat-free mass (FFM) predictive equation using multifrequency bioelectrical impedance analysis (BIA) data in adolescent soccer athletes. METHODS: Male adolescent soccer athletes (n = 149; 13-19 y old) were randomly sorted using Excel and independently selected for development group (n = 100) or cross-validation group (n = 49). The FFM reference values were determined using dual-energy X-ray absorptiometry. Single-frequency BIA was used to plot tolerance ellipses. Multifrequency-BIA raw data were used as independent variables in regression models. Student's independent t-test was used to compare development and cross-validation groups. Stepwise multiple regression was used to develop the FFM predictive equation. Bland-Altman plots, Lin's concordance correlation coefficient, according to McBride criteria, precision, accuracy, and standard error of estimate (SEE) were calculated to evaluate the concordance and reliability of estimates. Bioelectrical impedance vector analysis was plotted to assess hydration status. RESULTS: No differences (P > 0.05) were observed between development and validation groups in chronological age, anthropometric data, bioelectrical impedance data, and FFM values obtained using dual-energy X-ray absorptiometry. Bioelectrical impedance vector analysis tolerance showed that all participants presented adequate hydration status compared to the reference population. The new FFM predictive equation developed and validated: FFM (kg) = -7.064 + 0.592 × chronological age (y) + 0.554 × weight (kg) + 0.365 × height²/resistance (cm²/Ω), presented R² = 0.95; SEE = 1.76 kg; concordance correlation coefficient = 0.95, accuracy = 0.98, and strength of concordance = 0.99. CONCLUSIONS: The present study developed and cross-validated an FFM predictive equation based on multifrequency bioelectrical data providing substantial FFM accuracy for male adolescent soccer athletes.

Muscle quality and major adverse cardiovascular events in post-acute myocardial infarction: A prospective cohort study.

BACKGROUND & AIMS: Functional muscle quality, as assessed through the muscle quality index (MQI), represents a contemporary method to measure the capacity to generate force. Despite its potential, the prognostic significance of MQI remains uncertain in various clinical conditions, particularly among patients following acute myocardial infarction (AMI). In light of this, our study sought to evaluate the prognostic relevance of MQI concerning major adverse cardiovascular events (MACE) in patients following AMI. METHODS AND RESULTS: This is a secondary analysis of a prospective cohort study that included subjects aged ≥20 years from a Cardiovascular Unit Hospital. Functional muscle quality was estimated using MQI, defined as the ratio of handgrip strength (HGS) to muscle mass (MM) derived from bioelectrical impedance analysis. The outcomes included prolonged length of hospital stay, new adverse cardiovascular events (AMI, stroke and hospital readmission for unstable angina), and cardiovascular mortality. A composite score comprising all adverse events over the 1-year follow-up was calculated and defined as MACE. This study included 163 patients, with a median age of 61 years (IQ: 54-69 years), and the majority consisted of males (76.1%). Individual components of the functional muscle quality (HGS and MM) were not associated with any of the adverse outcomes. Only MQI was associated mortality over the 1-year follow-up. For each increase in MQI, the hazard of mortality decreases: adjusted HR: 0.08 (95% CI 0.01-0.84). CONCLUSION: Functional muscle quality assessed by the MQI may be a valuable clinical predictor of 1-year cardiovascular mortality in patients hospitalized post-AMI.