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Conjunction of Bioelectrical Impedance Spectroscopy with Archie’s Law to Characterize Scaffolds Porosity 9th

Conjunction of Bioelectrical Impedance Spectroscopy with Arc...

9th Latin American Congress on biomedical engineering, CLAIB 2022 and 28th Brazilian Congress on biomedical engineering, CBEB 2022

作者： Barbosa, Carlos Vinicius Nascimento de Souza, Marcio Nogueira Pino, Alexandre Visintainer COPPE/UFRJ/Biomedical Engineering Program Rio de Janeiro Brazil

ISBN: (纸本)9783031494000

Tissue engineering is a multidisciplinary field that uses two and three dimensional structures called scaffolds to create a physical support for growth, gas change and nutrition of the cell. Those scaffolds can be synthetic, biological or a combination of both types of material, but the porosity, the interconnectivity of pores and pore size are among the most important physical parameters of the scaffolds. The estimation of these characteristics is still a challenge in Tissue engineering, as it involves techniques and methods that need to be non-toxic and non-destructive, and that must operate in structures with dimensions of the order of micrometers (µm). The bioimpedance spectroscopy (bis) technique has been reported as a potential non-invasive monitoring of scaffold porosity and biological tissue growth. This work aims to study how bioimpedance spectroscopy in conjunction with Archiés law data can be used to characterize the porosity and pore connectivity of 3D cellular structures. © 2024, The Author(s), under exclusive license to Springer Nature Switzerland AG.

关键词： Pore size

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Singular spectrum analysis – an automatic detection technique for mean scatterer spacing estimation using ultrasound signals

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Research on biomedical engineering 2025年第2期41卷 1-16页

作者： Kauati, Adriana Cortela, Guillermo de Campos, Marcello L. R. Pereira, Wagner C. A. Programa de Pós-graduação em Engenharia Elétrica e Computação – CECE/UNIOESTE PR Foz do Iguaçu85870 650 Brazil Laboratorio de Acústica Ultrasónora – FCien/UdelaR Montevideo Uruguay Electrical Engineering Program – COPPE/UFRJ RJ Rio de Janeiro21941 - 914 Brazil Biomedical Engineering Program – COPPE/UFRJ RJ Rio de Janeiro21941 - 914 Brazil

Purpose: The article proposes an automated method for estimating mean scatterer spacing (MSS) in biological tissues using ultrasound signals. It employs singular spectrum analysis (SSA) with a novel entropy-based criterion to enhance accuracy and eliminate the need for manual parameter tuning. The method is validated using both simulated and real signals, demonstrating its effectiveness in detecting microstructural changes in tissues. Methods: The proposed SSA + entropy method estimates the MSS from ultrasound signals using SSA combined with a relative entropy-based criterion. This approach determines the optimal number of eigenvector pairs to reconstruct the periodic part of the signal by identifying the minimum in the entropy curve—a point that corresponds to the number of underlying periodic components, even in noisy conditions. For experimental validation, ex vivo bovine skeletal muscle was analyzed. RF data were collected at a controlled temperature of using a 3.5-MHz transducer. The MSS results obtained via SSA were also independently verified using microscopy and image analysis of muscle fiber spacing, confirming the effectiveness of the entropy-based SSA approach. Results: The MSS estimation method's accuracy decreases as jitter or Ad noise levels increase, with the method performing well when the estimated MSS is within 10% of the true value. Additionally, the standard deviation of MSS estimates increases as Ad levels and jitter values rise. In phantom experiments, MSS was measured using different transducer frequencies with varying results at each frequency. When applied to ex vivo bovine skeletal muscle tissue, the MSS estimation was validated using both RF and imaging methods, with three consistent groups of MSS values observed, confirming the method's applicability and reliability. Conclusion: The proposed method combines SSA and entropy to automatically estimate medium periodicity in ultrasound, eliminating the need for operator intervention. It succes

关键词： Image analysis

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In Vitro Degradation of Polydioxanone (PDO) Lifting Threads in Microfocused Ultrasound

In Vitro Degradation of Polydioxanone (PDO) Lifting Threads ...

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2024 Global Medical engineering Physics Exchanges/Pan American Health Care Exchanges, GMEPE/PAHCE 2024

作者： Silva, M.H.R. Raybolt, A. Pereira, W.C.A. Federal University of Rio de Janeiro Biomedical Engineering Program - Coppe RJ Brazil Federal University of Rio de Janeiro School of Dentistry RJ Brazil

ISBN: (纸本)9798350390490

Objective: Analyze the static degradation time of polydioxanone (PDO) threads with or without the association of microfocused ultrasound, which are techniques for aesthetic purposes. Materials and Methods: In vitro assays were conducted in isotonic solution using smooth polydioxanone (PDO) threads divided into 2 groups (n=3): FPL (Smooth Polydioxanone Thread) and FPLU (Smooth Polydioxanone Thread with Ultrasound). The FPLU group underwent microfocused ultrasound. Both groups endured the following analyses: UV spectroscopy Absorbance and Scanning Electron Microscopy (SEM). Results: Absorbance by UV spectroscopy: The concentration levels of molecules in the aliquots showed that at 8 days both FPL and FPLU groups exhibited absorbance levels of 0.0040 (mol-1/***-1) and 0.00585 (mol-1/***-1), respectively. At 30 days, these levels were 0.0799 (mol-1/***-1) and 0.0543 (mol-1/***-1). At 60 days, the FPLU group showed significant increase to 0.2039 (mol-1/***-1) compared to the FPL group at 0.1152 (mol-1/***-1) reaching a degradation peaks at 60 days. At 90 days, the FPL group presented 0.1299 (mol-1/***-1) and the FPLU group presented 0.2377 (mol-1/***-1). SEM: Morphological differences were observed in both groups. Conclusion: FPLU group showed higher absorbance over time. Microfocused ultrasound accelerated degradation time PDO threads, diminishing its functionality. © 2024 IEEE.

关键词： Ultrasonics

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Ultrasonography Validation of Condylar and Pre-Condylar Distances and its Correlation with the Arthralgia Intensity Attributed to Local Arthritis

Ultrasonography Validation of Condylar and Pre-Condylar Dist...

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2024 Global Medical engineering Physics Exchanges/Pan American Health Care Exchanges, GMEPE/PAHCE 2024

作者： El-Sayed, C. Goffredo Filho, G.S. Sad, L. Tesch, R.S. Pereira, W.C.A. COPPE/Federal University of Rio de Janeiro Biomedical Engineering Program RJ Rio de Janeiro Brazil Petrópolis Medical School Tmd and Orofacial Pain Department RJ Petrópolis Brazil

ISBN: (纸本)9798350390490

Temporomandibular disorders (TMD) represent a prevalent form of musculoskeletal pain observed in individuals with chronic pain. Timely and accurate diagnosis is essential for effective therapeutic interventions, with imaging examinations playing a crucial role in assessing articular structures, as outlined by the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD). Given the significance of temporomandibular joint (TMJ) evaluation in dentistry, the integration of ultrasonography (USG) into clinical practice facilitates early detection of joint pathologies. This study aims to evaluate the correlation between condylar and pre-condylar measures to determine which more accurately reflects capsular expansion associated with intra-articular effusion and the intensity of arthralgia reported by patients in the future. Measurements of condylar and pre-condylar distances were conducted in a cohort of volunteers. The Spearman correlation coefficient between condylar and pre-condylar distances was determined to be 0.36. The results suggest a statistically moderate correlation between condylar and pre-condylar measures, indicating that the latter may serve as a potentially less biased and more valid screening tool for identifying capsular expansions attributed to intra-articular inflammation and associated pain in patients with TMD. © 2024 IEEE.

关键词： Ultrasonography

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Use of Endoluminal and Transabdominal Ultrasound Biomicroscopy to Measure Colon Wall Thickness in Healthy and Tumor-Bearing Mice

Use of Endoluminal and Transabdominal Ultrasound Biomicrosco...

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Ultrasonics Symposium (LAUS), IEEE UFFC Latin America

作者： Juliana Oliveira da Silva Fernandes Rodrigo Pereira de Oliveira João Carlos Machado Biomedical Engineering Program/COPPE Federal University of Rio de Janeiro Rio de Janeiro Brazil Biomedical Engineering Program/COPPE and Post-Graduation Program in Surgical Sciences/Department of Surgery/School of Medicine Federal University of Rio de Janeiro Rio de Janeiro Brazil

ISBN: (数字)9798350349085

ISBN: (纸本)9798350349092

Colorectal cancer (CRC) ranks among the most prevalent tumors, particularly affecting men and women, with mouse models and imaging technologies like colonoscopy, endoluminal (eUBM), and transabdominal (tUBM) ultrasound biomicroscopy playing pivotal roles in exploring new treatment avenues. The evaluation of colon wall thickness (Wt), a significant marker of tumor presence, is feasible through eUBM or tUBM, contrasting with colonoscopy's limitations. This study scrutinizes the consistency of Wt measurements obtained via eUBM and tUBM in mice, with or without colon tumors induced by azoxymethane (AOM) and dextran sulfate sodium salt (DSS). UBM images were captured using both eUBM and tUBM instruments, with subsequent Wt measurements performed using ImageJ software. Comparison between Wt obtained from eUBM and tUBM images used the One-Way ANOVA, for normal distributed data, or the Kruskal-Wallis test otherwise. Local Ethics Committee for Animal Use in Research approved the work (protocol 014/20). In general, the results indicate a substantial median Wt disparity between control and tumor groups measured by both techniques (p<0.05). Notably, discrepancies in Wt findings between the two methods were observed in the control group (p<0.05), despite the excellent resolution of the images in delineating colon layers.

关键词： Ultrasonic imaging Ultrasonic variables measurement Colonoscopy Mice Colon Software measurement Spatial resolution

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Exploring the Impact on Collapse and Ultrasound Backscattered Signal Intensity with Varying Ultrasound Power Incident on Gas Vesicle Used for Contrast Agent

Exploring the Impact on Collapse and Ultrasound Backscattere...

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Ultrasonics Symposium (LAUS), IEEE UFFC Latin America

作者： Mariana Rocha Da Silva Flávia Maria Carra Pereira De Jesus Felipe Vianna Garrute João Carlos Machado Biomedical Engineering Program-COPPE Federal University of Rio de Janeiro Rio de Janeiro Brazil Department of Surgery Biomedical Engineering Program-COPPE and Post-Graduation Program in Surgical Sciences School of Medicine Federal University of Rio de Janeiro Rio de Janeiro Brazil

ISBN: (数字)9798350349085

ISBN: (纸本)9798350349092

Gas vesicles (GVs), gas-filled protein-encapsulated nanostructures, synthesized by microorganisms such as Halobacterium salinarum NRC-1 (HALO) and Anabaena flos aquae (ANA) have been reported as potential ultrasound contrast agents (UCA) due to their ability to mechanically vibrate with the same frequency, or harmonics, as the one from the incident ultrasound (US) wave. Despite GVs resonating in frequencies above 21 MHz, they collapse irreversibly when the US incident field pressure exceeds the vesicle collapse pressure. There are few reports on the relationship between the pressure of the acoustic wave incident in the GVs and the corresponding intensity of the backscattered wave signal from the GVs and, therefore, this study was designed to investigate how varying the relative incident US power, at 21MHz, reflects on the intensity of the US backscattered signal and the collapse of HALO and ANA GVs. The mean (±SD) of the grey level intensity for the ROIs, in maximum intensity pixel images, with GVs and PBS, were determined for transmitted acoustic relative power of 1, 5, 10, 20%. ANA-GVs presented a lower signal intensity, but greater resistance to the increase in relative US pressure. In conclusion, the best behavior was for the Halo-GVs at 5% power and at 21MHz frequency.

关键词： Resistance Proteins Frequency synthesizers Ultrasonic imaging Microorganisms Resonant frequency Harmonic analysis

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Thermographic Analysis in a Multilayer Medium Cortical Bone/Cancellous Bone/Bone Cement Heated by Therapeutic Ultrasound 9th

Thermographic Analysis in a Multilayer Medium Cortical Bone/...

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9th Latin American Congress on biomedical engineering, CLAIB 2022 and 28th Brazilian Congress on biomedical engineering, CBEB 2022

作者： dos Santos, B.T.M.T. de Oliveira, L.V.C. Lopes, A.M.C. Pereira, L.F. Pereira, A.J.F. Omena, T.P. Pereira, W.C.A. UFRJ/COPPE/ Biomedical Engineering Program Av. Horácio Macedo 2030 Centro de Tecnologia COPPE/UFRJ Bloco H S. 327 Rio de Janeiro Brazil UFRJ/Physiotherapy Department Rio de Janeiro Brazil University Centre Serra Dos Órgãos Rio de Janeiro Brazil

ISBN: (纸本)9783031494000

The thermal effects of therapeutic ultrasound are used to produce analgesia or reduce inflammation in biological tissues. However, it is contraindicated on regions with cemented prostheses, due to the supposed heating of it. The present study aims to evaluate the heating pattern in a multilayer medium, using cortical bone phantom, cancellous bone phantoms and, bone cement specimen. It was observed that the cancellous bone phantom was the one that warmed the most, reaching an average temperature of 33.89 ± 1.89 ºC, while the bone cement specimen barely changed. In the multilayer medium, the heating pattern was more superficial than expected. More studies are needed to elucidate the influence of application time and intensity in ultrasonic irradiation in places with the presence of bone cement in treatment protocols. © 2024, The Author(s), under exclusive license to Springer Nature Switzerland AG.

关键词： Phantoms

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Microvolt T-Wave and Ventricular Repolarization Duration Alternans 9th

Microvolt T-Wave and Ventricular Repolarization Duration Alt...

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9th Latin American Congress on biomedical engineering, CLAIB 2022 and 28th Brazilian Congress on biomedical engineering, CBEB 2022

作者： Winkert, Thaís Nadal, Jurandir Benchimol-Barbosa, Paulo Roberto Biomedical Engineering Program COPPE Institute Universidade Federal do Rio de Janeiro Rio de Janeiro Brazil Hospital Universitário Pedro Ernesto Universidade do Estado do Rio de Janeiro Rio de Janeiro Brazil

ISBN: (纸本)9783031494031

The ventricular tachyarrhythmia is an important cause of sudden cardiac death, impacting economic, social, and health systems. Microvolt T-wave alternans (MTWA) represent transmural gradient alternation in phase-3 ventricular action potential duration, leading to T-wave amplitude shortening in every other beat. The T-peak T-end interval (TpTe) represents the terminal ventricular repolarization duration and is explained by differences in phase-3 repolarization times from ventricular epicardial to endocardial fibers. Whether TpTe alternation occurs in patients with MTWA is unknown. This work investigated whether terminal ventricular repolarization duration alternation is present in MTWA patients. Seven 12-lead ECG records from Physionet T-wave Alternans Database were analyzed. The TpTe alternans was assessed in even and odds beats, in a series of 128 consecutive beats. In even and odd beats, TpTe intervals were ensembled and averaged, and the magnitude of TpTe alternans was defined as the difference between averages (ΔTpTe). The MTWA was quantified by the difference between the average peak of the T-wave in even and odd beats. ΔTpTe and MTWA were compared by Pearson’s coefficient. Even and odd beats on TpTe alternans and MTWA were compared with non-paired Student t-tests. ΔTpTe positively correlated with MTWA (r = 0.5;p © The Author(s), under exclusive license to Springer Nature Switzerland AG 2024.

关键词： Electrocardiograms

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IIWM (Integration ImageJ with MATLAB) program for Segmentation and Volume Estimation in Ultrasound Biomicroscopic Images of Mouse Colon Tumor

IIWM (Integration ImageJ with MATLAB) Program for Segmentati...

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Ultrasonics Symposium (LAUS), IEEE UFFC Latin America

作者： Igor Soares Colonna Yasmin Farias Romi de Sant'Anna Rodrigo Pereira de Oliveira João Carlos Machado Biomedical Engineering Program/COPPE Federal University of Rio de Janeiro Rio de Janeiro Brazil INFNET Institute Rio de Janeiro Brazil Department of Surgery Biomedical Engineering Program/COPPE and Post-Graduation Program in Surgical Sciences School of Medicine Federal University of Rio de Janeiro Rio de Janeiro Brazil

ISBN: (数字)9798350349085

ISBN: (纸本)9798350349092

This article proposes the creation, implementation and development of an integration plugin for ImageJ that makes calls in MATLAB functions for the segmentation UBM imagens, more specific endoluminal (eUBM) e transabdominal (tUBM), in the laboratory the images are generating with frequencies between 30-40 MHZ. These images allow view colon layer, identify tumors in colons, to calculate tumor volume and 3D visualization. This integration may to improve the time taken to perform the procedure and the user experience to reduce the number of tasks and change windows, making the experience more fluid and with less risk of errors.

关键词： Solid modeling Image segmentation Visualization Ultrasonic imaging Three-dimensional displays Biological system modeling Volume measurement

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Characterization of Thermal Properties of Polymethylmethacrylate Bone Cement for Therapeutic Ultrasound Application

Characterization of Thermal Properties of Polymethylmethacry...

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Pan American Health Care Exchanges, PAHCE

作者： A. M. C. Lopes K. A. Coelho L. F. Pereira W. C. A. Pereira Biomedical Engineering Program - COPPE Federal University of Rio de Janeiro Rio de Janeiro Brazil

Biomaterials interact with biological systems and are intended to replace tissues and body organ functions. They can be classified as natural or synthetic. Polymethylmethacrylate (PMMA) is a synthetic biomaterial used, from the 1940’s to the present day, in orthopedic surgeries to replace joint surfaces and/or repair fractures. The basis of its components remains the same, small changes create variations in its properties; therefore, it is necessary to measure them. This work aims to characterize the thermal properties of PMMA, comparing them with those of soft tissues, bone and metallic prosthesis. The PMMA sample was stimulated 11 times for 3 seconds each by the modified transient plane source (MTPS), presenting the following averages: thermal conductivity =0.229± 0.006K(W/mK); effusivity =581.20± 6.22W$\mathrm{s}^{1/2}$/$\mathrm{m}^{2}$K and specific heat =1204.23± 6.88 ***. oC-1. The thermal properties obtained suggest that the cement would not cause local overheating, thus enabling the use of TUS on the region containing PMMA. The metallic prosthesis seems to play an important role in the dissipation of the heat generated, contributing to the non-heating of the multilayer system. However, more studies are needed to clarify this issue.

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