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arXiv 2022年

作者： Moreno, Eduardo Pereira, Wagner C.A. von Kruger, Marco Antonio Leija, Lorenzo Ramos, Antonio Ultrasonic Group ICIMAF Calle 15 No 551 Vedado La Habana Cuba Biomedical Engineering Program COPPE UFRJ 2030 Horacio Macedo Ave Rio de Janeiro21941-914 Brazil Department of Electrical Engineering Bioelectronics Section Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional Cinvestav México City Mexico R&D Group "Sistemas y Tecnologías Ultrasónicas" Instituto de Tecnologías Físicas y de la Información CSIC Madrid Spain

A FEM application for the accurate design of composite backing of ultrasonic transducers is presented. The idea is to obtain the dependence between the volume ratio of the tungsten powder in an epoxy matrix used as a backing and the final pulsed RF signal emitted by the backed transducer. An inhomogeneous material model for the backing was adopted instead of the classic complex geometrical FEM. The model was developed in Comsol 5.5 using two of its physics interfaces. The first based on classic FEM or continuous Galerkin for ultrasonic propagation in the backing and the second based on a discontinuous Galerkin option for fluid pulsed propagation. In this way it is possible to avoid the use of an impedance-based model. The calculations for the resulting bandwidth are good enough as predicted for Desilets for the 1D case by using the KLM circuital model. We worked in a 2D space, where the transducer face vibration is far away from the assumed piston-like considered by the unidimensional KLM model. © 2022, CC BY.

关键词： Finite element method

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Erratum to: A Numerical Model of the Respiratory Modulation of Pulmonary Shunt and PaO2 Oscillations for Acute Lung Injury

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Annals of biomedical engineering 2010年第7期38卷 2473-2473页

作者： Beda, Alessandro Jandre, Frederico C. Giannella-Neto, Antonio Pulmonary Engineering Lab Biomedical Engineering Program COPPE – Federal University of Rio de Janeiro Rio de Janeiro Brazil Pulmonary Engineering Group Clinic of Anesthesiology and Intensive Care Therapy University Clinic Carl Gustav Carus Technical University Dresden Dresden Germany

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Ultrasound propagation through bone fractures with reamed intramedullary nailing: results from numerical simulations

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Proceedings of Meetings on Acoustics 2013年第1期19卷

作者： Fernanda Catelani Ana Paula M. Ribeiro Carlos Alberto V. Melo Wagner C. Pereira Christiano B. Machado COPPE - Biomedical Engineering Program Federal University of Rio de Janeiro Brazil Biomedical Ultrasound Laboratory Estácio de Sá University Brazil Physical Therapy Department Estácio de Sá University Brazil Biomedical Ultrasound Laboratory Estácio de Sá University Sans Souci s/n Nova Friburgo Rio de Janeiro 28600000 Brazil

Low-intensity pulsed ultrasound stimulation (LIPUS) accelerates fracture healing, enhancing the release of inflammatory mediators and subsequent bone formation. The reamed intramedullary nailing (with the same diameter of the medullary cavity) is a surgical procedure widely used in Medicine. The aim of this work was to study ultrasound propagation inside fractures with and without reamed intramedullary nailing using 2D simulations. It was used a custom-made simulation code applied to numerical models (a 4-mm thick cortical plate, a medullary cavity with radius 4 mm with and without reamed nailing, and fracture gaps varying from 1 to 3 mm). A 1-MHz emitter was positioned above fracture center and fourteen receptor transducers were uniformly placed inside fracture gap. The acquired signals were used to estimate the time-of-flight of the first arriving signal (TOF) and the energy amplitude by means of the root mean square (RMS). TOF was slightly influenced by fracture gap variations. It was observed an increase in RMS values with the presence of metal nailing, due to the reflection in the interface water-metal. The receptors placed near cortical plates received more energy (constructive interference between the direct and lateral waves). For the case of reamed nailing, ultrasound stimulation may be intensified.

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Effects of Intense Physical Activity with Free Water Replacement on Bioimpedance Parameters and Body Fluid Estimates

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Journal of Physics: Conference Series 2012年第1期407卷

作者： E B Neves L Ulbricht E Krueger E F R Romaneli M N Souza Biomedical Engineering Master Program/PPGEB Federal Technological University of Paraná Av. Sete de Setembro 3165 80230-901 Curitiba/PR Brazil Rehabilitation Engineering Laboratory Federal Technological University of Paraná Av. Sete de Setembro 3165 80230-901 Brazil Automation and Control Engineering Academic Department of Electrotechnics Federal Technological University of Paraná Av. Sete de Setembro 3165 80230-901 Brazil Biomedical Engineering Program – COPPE/UFRJ Centro de Tecnologia Bloco H sala 327 21949-900 Brazil

Authors have emphasized the need for previous care in order to perform reliable bioimpedance acquisition. Despite of this need some authors have reported that intense physical training has little effect on Bioimpedance Analysis (BIA), while other ones have observed significant effects on bioimpedance parameters in the same condition, leading to body composition estimates considered incompatible with human physiology. The aim of this work was to quantify the changes in bioimpedance parameters, as well as in body fluids estimates by BIA, after four hours of intense physical activity with free water replacement in young males. Xitron Hydra 4200 equipment was used to acquire bioimpedance data before and immediately after the physical training. After data acquisition body fluids were estimates from bioimpedance parameters. Height and weight of all subjects were also acquired to the nearest 0.1 cm and 0.1 kg, respectively. Results point that among the bioimpedance parameter, extracellular resistance presented the most coherent behavior, leading to reliable estimates of the extracellular fluid and part of the total body water. Results also show decreases in height and weight of the participants, which were associated to the decrease in body hydration and in intervertebral discs.

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Comparative Study between Ultrasound Biomicroscopy and Histopathology of Diversion Colitis on Rats

Comparative Study between Ultrasound Biomicroscopy and Histo...

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2008 IEEE International Ultrasonics Symposium(IUS)(2008 IEEE国际超声研讨会)

作者： Rodrigo Pacheco Kelly Alves Christiano Espósito Monica Soldan Leonardo Quintella Vera Chagas Alberto Schanaider Joao Maehado School of Medicine Federal University of Rio de Janeiro Department of Pathology Rio de Janeiro RJBrazil COPPE/Federal University of Rio de Janeiro Biomedical Engineering Program Rio de Janeiro RJ Brazil Clementino Fraga Filho University Hospital-Federal University of Rio de Janeiro Division of Pathological Anatomy Rio de Janeiro RJBrazil School of Medicine Federal University of Rio de Janeiro Department of Surgery-Center of Experimental Surgery Rio de Janeiro RJBrazil Clementino Fraga Filho University Hospital-Federal University of Rio de.Janeiro Division of Gastroenterology Endoscopy Unit Rio de Janeiro RJ Brazil

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Effect of the ultrasound wave propagation regime in the heat source term of Penne’s bio-heat transfer equation

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Proceedings of Meetings on Acoustics 2016年第1期28卷

作者： Guillermo Cortela Carlos Negreira Wagner C. A. Pereira 1Laboratorio de Acústica Ultrasónica University of the Republic Montevideo Uruguay gcortela@fisica.edu.uy carlosn@fisica.edu.uy 2Biomedical Engineering Program COPPE/Federal University of Rio de Janeiro Brazilwagner@peb.ufrj.br

This work analyses the influence of the ultrasound wave propagation regime on the temperature increase on biological media. Simulated and experimental temperature values from bovine ex-vivo tissue in two different depths, 5 and 40 mm, respectively smaller and bigger than the mean free propagation path (ℓS = 8.52 mm), are obtained. Temperature curves measured during US therapeutic application (High Intensity Therapeutic Ultrasound, HITU, 1 MHz, 1.5 – 2.0 Wcm−2) for 10 min, are compared to simulated ones using the Penne’s bio-heat transfer equation (BHTE) at the same frequency and intensities and using the standard source term (ultrasonic absorption coefficient). At 5 mm, estimated and measured temperature diverge no more than 1%, while at 40 mm, when the scattering starts being not negligible, the simulated temperature is 20% smaller than the measured one. The results indicate that absorption increases when the wave propagation regime changes for depths greater than the ℓS value.

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Comparative Study between Ultrasound Biomicroscopy and Histopathology of Diversion Colitis on Rats

Comparative Study between Ultrasound Biomicroscopy and Histo...

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2008 IEEE International Ultrasonics Symposium

作者： Rodrigo Pacheco Kelly Alves Christiano Espósito Monica Soldan Leonardo Quintella Vera Chagas Alberto Schanaider Joao Machado School of Medicine Federal University of Rio de JaneiroDepartment of Surgery Center of Experimental Surgery.Rio de Janeiro COPPE/Federal University of Rio de Janeiro Biomedical Engineering ProgramRio de Janeiro School of Medicine Federal University of Rio de JaneiroDepartment of Surgery Center of Experimental SurgeryRio de Janeiro Clementino Fraga Filho University Hospital-Federal University of Rio de Janeiro Division of GastroenterologyEndoscopy UnitRio de Janeiro Clementino Fraga Filho University Hospital-Federal University of Rio de Janeiro Division of Pathological AnatomyRio de Janeiro School of Medicine Federal University of Rio de JaneiroDepartment of PathologyRio de Janeiro

Background,Motivation and Objective Diversion colitis is a nonspecific inflammatory process observed in excluded colonic segments and the pathogenesis is *** evaluation and diagnosis usually require endoscopic and his... 详细信息

关键词： UBM Comparative Study between Ultrasound Biomicroscopy and Histopathology of Diversion Colitis on Rats

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Applying Genetic Algorithms to Optimise Breast Ultrasound Images Segmentation Procedure Based on Morphological Operators

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The Journal of the Acoustical Society of America 2008年第5_SUPPLEMENT期123卷 3226-3226页

作者： Andre V. Alvarenga Wagner C. Pereira Antonio F. Infantosi Carolina M. Azevedo Laboratory of Ultrasound ‐ Inmetro Av. N. Sra. das Gracas 50 predio 1 ‐ Xerem 25250‐020 Duque de Caxias ‐ Rio de Janeiro Brazil avalvarenga@inmetro.gov.br Biomedical Engineering Program ‐ COPPE Federal University of Rio de Janeiro CEP. 21.941‐972 Rio de Janeiro Brazil wagner@peb.ufrj.br Biomedical Engineering Program ‐ COPPE Federal University of Rio de Janeiro CEP. 21.941‐972 Rio de Janeiro Brazil afci@peb.ufrj.br Brazilian National Cancer Institute ‐ INCa Praça da Cruz Vermelha 23 20230‐130 Rio de Janeiro Brazil azevedocma@bol.com.br

Ultrasound (US) image segmentation is a complex problem due its textural nature. To address this difficulty, different segmentation procedures have been described to support radiologists in recognising abnormal US‐image areas. This work proposes a procedure, based on Genetic Algorithms (GA) and Morphological Operators (MO), to segment breast tumours on ultrasound images. Each chromosome represents a complete image processing sequence, composed of MOs and structuring elements (SE). The GA generates 500 chromosomes of 93 genes, where the three first genes summed indicate the number of performed operations, the following 45 genes represent the operations' sequence, and the last 45, the SE‐disk diameter (in pixel). The best segmentation sequence (best chromosome) is selected using an objective function, based on the weighted sum of the number of false‐positive and false‐negative pixels. The gold standards are the tumour contours depicted by an experienced radiologist. Twenty images are used to train the GA procedure, and the best chromosome tested with 40 different images. The performance of the procedure is assessed using the overlap ratio among the obtained segmentation and the gold standard. All tested images present an area overlap ratio superior to 70%. This initial result encourages us to go further by increasing the number of images.

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Multilayered non‐invasive temperature estimation from backscattered ultrasound

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The Journal of the Acoustical Society of America 2008年第5_SUPPLEMENT期123卷 3227-3227页

作者： Cesar A. Teixeira Maria Graça Ruano António Ruano Wagner C. Pereira University of Algarve Faculty of Sciences and Technology Campus de Gambelas 8005‐139 Faro Portugal cteixei@*** University of Algarve Faculty of Sciences and Technology Campus de Gambelas 8005‐139 Faro Portugal mruano@ualg.pt University of Algarve Faculty of Sciences and Technology Campus de Gambelas 8005‐139 Faro Portugal aruano@ualg.pt Biomedical Engineering Program ‐ COPPE Federal University of Rio de Janeiro CEP. 21.941‐972 Rio de Janeiro Brazil wagner@peb.ufrj.br

A major drawback on the application of thermal therapies is the lack of reliable knowledge about temperature in the region under treatment. The most attractive approach is non‐invasive temperature estimation (NITE) strategies and, among them, techniques based on backscattered ultrasound (BSU) are a convenient choice for its portability and simplicity. Using BSU some methods have been proposed for temperature estimation basically for homogeneous media, and simple operating situations. More complex scenarios can be explored by non‐linear approaches. In this work, a methodology based on neural networks is presented for temperature estimation in a multilayer phantom. A three‐layer gel‐based phantom was heated at eight intensities, between 0.30 and 2.0 W/cm2 (at 1MHz) for 15 minutes. Temperature and BSU signals were acquired from five spatial‐points at each 10 seconds. Temporal echo‐shifts, induced by temperature change, were computed from the BSU signals, and used as model's input information. Neural models were developed to estimate temperature at four intensities. Then models were validated in data including all the intensities. The best model presents a maximum absolute error of 0.43 °C for untrained situations. To the best of our knowledge this is the first NITE approach in multilayered media.

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Ultrasonic calibration and certification of V1 and V2 type reference standard blocks for use in Non-Destructive Testing

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Journal of Physics: Conference Series 2011年第1期279卷

作者： L E Maggi C E R Silva A V Alvarenga R P B Costa-Felix Laboratory of Ultrasound Directory of Scientific and Industrial Metrology (DIMCI) National Institute of Metrology Standardization and Industrial Quality (INMETRO) Av. Nossa Sra das Graças 50 (Prédio 1) Duque de Caxias RJ Brazil ZIP 25250-020 Biomedical Engineering Program COPPE/Federal University of Rio de Janeiro (UFRJ) Horácio Macedo Ave. n 2030 Center of Technology Block H - room/327 Cidade Universitária Rio de Janeiro RJ Brazil ZIP 21941-914

Ultrasonic Non-Destructive Testing (US-NDT) has many industrial applications, such as flaws detection, welding integrity evaluation and solid material thickness measurement. To evaluate the instrumentation conditions, before a measurement begins, a 'calibration' should be carried out with the aid of a reference standard block (RSB). Types V1 (ISO 2400) and V2 (ISO 7963) are the most widely used in US-NDT. Due their characteristics, V1 and V2 RSB can be classified as Reference Material, so that they can be certified, resulting in a Certified Reference Material (CRM). This paper describes technical aspects of a V1 and V2 RSB certification, based on ISO 2400, ISO 7963, EN 12223 and EN 27963. According the certification protocol established at Inmetro's Laboratory of Ultrasound, RSB relevant dimensions were determined through calibration. Ultrasound velocity was assessed by using a scope and a signal generator at 5 MHz. Uncertainties were determined including measurement accuracy under repeatability conditions. A complete uncertainty budget was determined for both parameters. Within the specimens used, velocities were in accordance with specifications 5920 ± 30 m/s.

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