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Pan American Health Care Exchanges, PAHCE

作者： C. B. Machado W. C. A. Pereira M. Talmant F. Padilla P. Laugier Biomedical Engineering Program-COPPE UFRJ Rio de Janeiro Brazil Laboratoire dImagerie Paramétrique Université Paris 1 France Department of Radiology University of Michigan Medical Center MI USA

The present work aims at studying the effect of cortical bone mineralization on ultrasound axial transmission (UAT) measurements, using experiments and numerical simulations. To this end, a reverse fracture healing approach is proposed, using an in vitro bovine femur sample. A demineralization protocol was applied, and the time-of-flight of the wave propagating in axial transmission measured. Numerical simulations of the experimental situation were also implemented. Mineralization degree may influence ultrasound measurements, and it may be a promising tool for fracture healing assessment.

关键词： Bones Ultrasonic imaging Ultrasonic variables measurement Numerical simulation biomedical measurements Mineralization Acoustics

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Active contours without edges applied to breast lesions on ultrasound

Active contours without edges applied to breast lesions on u...

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作者： Gómez, W. Infantosi, A.F.C. Leija, L. Pereira, W.C.A. Department of Electrical Engineering CINVESTAV-IPN Mexico D.F. Mexico Biomedical Engineering Program COPPE/UFRJ Cidade Universitária Horácio Macedo Ave. 2030 Rio de Janeiro Brazil

ISBN: (纸本)9783642130380

A computerized lesion segmentation technique for breast ultrasound images is proposed. It uses a deformable model based on active contours without edges. The performance of this technique was accessed by comparing the resulting contours of 50 ultrasonographies with those manually delineated by two radiologists. For the boundary, the error metrics used were the Hausdorff distance (HD) and the mean absolute distance (MD). The error area was assessed by using the percentage of false positive (FP), false negative (FN), and true positive (TP) pixels. The results were HD = 8.76±6.04, MD = 2.78±1.20, FP = 4.98±3.83, FN = 16.19±6.85, and TP = 83.86±6.75. These findings indicate that the proposed technique was capable to reach high detailed contours. © 2010 International Federation for Medical and Biological engineering.

关键词： Image segmentation

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Breast ultrasound imaging phantom to mimic malign lesion characteristics

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Physics Procedia 2010年第1期3卷 421-426页

作者： I.M. de Carvalho R.L.Q. Basto A.F.C. Infantosi M.A. von Krüger W.C.A. Pereira Biomedical Engineering Program COPPE/UFRJ Av. Horacio Macedo 2030 Rio de Janeiro 21941-914 Brazil

Ultrasound (US) phantoms are used to simulate the main acoustic properties of human soft tissues and are usually applied in guided biopsy training and equipment calibration. In this work it is presented an ultrasound phantom that mimics breast lesions with irregular edge, which is a typical feature related to malignancy. The phantom matrix was made of a mixture of water, agar, glycerine and graphite and PVC powders and the lesions were of silicon and polyacrylamide. The mimicking properties were US attenuation, propagation speed and density. The images obtained were visually compatible to malignant and benign lesions and are meant to be used as references for evaluation of segmentation algorithms for image processing.

关键词： Breast Phantom Ultrasound

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Semiautomatic contour detection of breast lesions in ultrasonic images with morphological operators and average radial derivative function

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Physics Procedia 2010年第1期3卷 373-380页

作者： W. Gómez L. Leija W.C.A. Pereira A.F.C. Infantosi Department of Electrical Engineering CINVESTAV-IPN Av. IPN 2508 Mexico City 07000 Mexico Biomedical Engineering Program COPPE/UFRJ Av. Horacio Macedo 2030 Rio de Janeiro 21941-914 Brazil

This work presents a computerized lesion segmentation technique on breast ultrasound images. There were applied known techniques such as morphological filtering, Watershed transformation and average radial derivative function. To evaluate the performance of the proposed method, two protocols were established. For the first, the resulting segmentation contours were compared with those of 24 gold standard simulated ultrasound-like images, and, for second, with 36 breast US images manually delineated by two senior radiologists. Further, two evaluation parameters were used: the percentage of coincidence (CP) and the proportional distance (PD). The former indicates the similarity between contours, while the latter express the dissimilarity. The accuracy of the proposed method was evaluated by considering images with CP>80% and PD<10% as adequately delineated. It was higher than 80% for real images and higher than 88% for simulated images.

关键词： Average radial derivative Breast ultrasound Morphological operators Segmentation

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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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Sensibility of hydrous ethanol adulteration detection using ultrasonic parameters validated in a metrological base

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

作者： Monique K-K Figueiredo Rodrigo P B Costa-Felix Luis E Maggi André V Alvarenga Gilberto A Romeiro Laboratory of Ultrasound (LABUS) 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 Depto of Organic Chemistry Institute of Chemistry Fluminense Federal University (UFF) Campus of ValonguinhoOuteiro de São João Batista s/n Niteroi RJ Brazil ZIP 24020150 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

The aim of this study is to identify possible changes in fuels, in this case hydrous ethanol, through ultrasonic parameters such as attenuation and propagation speed. The system setup and method were implemented at Inmetro's Laboratory of Ultrasound. Experiments and method uncertainties were assessed accordingly to ISO/IEC Guide 98 1:2009 (Uncertainty of measurement - Part 1: Introduction to the expression of uncertainty in measurement). Mixtures of ethanol and water varying from 90% to 94% of alcohol in mass were used as testing samples. Attenuation and propagation speed were accurately measured and uncertainties evaluated. The accordingly to Brazilian biofuel regulations, the concentration of water in hydrous ethanol can be accepted at a maximum concentration of 93.8 and minimum of 92.6 of alcohol in mass. To achieve that figure, a functional combination of tested parameters should be implemented. Those results could be used as a tool to identify adulteration of biofuel, even in analysis performed on site.

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Using ANOVA to analyse thalidomide’s molecular mechanisms in human PBMC microarrays

Using ANOVA to analyse thalidomide’s molecular mechanisms i...

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IEEE Symposium on Bioinformatics and Bioengineering (BIBE)

作者： Renata T. Paiva Barbara C. Dias Marcelo Ribeiro-Alves Ulisses G. Lopes Flavio F. Nobre MSc student Biomedical Engineering Program COPPE/UFRJ Rio de Janeiro Brazil Centre for Technological Development Health FIOCRUZ Rio de Janeiro Brazil Structural and Molecular Biology Program IBCCF/UFRJ Rio de Janeiro Brazil Biomedical Engineering Program COPPE/UFRJ Rio de Janeiro Brazil

Thalidomide is an anti-inflammatory and immunomodulatory drug that is the treatment of choice for erythema nodosum leprosum (ENL), an inflammatory cutaneous and systemic complication of multibacillary leprosy. Its use in leprosy and other conditions is controversial due to its teratogenic effects. Fifty years after the development of thalidomide, its action mechanism is still not well understood. In the present study we analyzed the in vitro effect of thalidomide on global gene expression in cultured human Peripheral Blood Mononuclear Cells (PBMC) of normal donors. We normalized the background subtracted spotted cDNA microarray data using a locally weighted linear regression and modeled its residual by a two-step analysis of variance to detect differentially expressed PBMC human genes in response to thalidomide. Using the full set of spotted genes, 13 genes were identified as differentially expressed genes. A reduced set was derived with a direct simple filtering approach and this set resulted in eight differentially expressed genes. Among these 21 genes, 15 are involved in the immune regulation processes.

关键词： Analysis of variance Humans Immune system Drugs In vitro Gene expression Blood Cells (biology) Linear regression Filtering

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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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A comparison between impedance measured by a commercial analyzer and your value adjusted by a theoretical model in body composition evaluation

A comparison between impedance measured by a commercial anal...

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Annual International Conference of the IEEE engineering in Medicine and Biology Society (EMBC)

作者： C.E.B. Neves M.N. Souza Biomedical Engineering Program - COPPE/UFRJ Rio de Janeiro Brazil Exercise Physiology Laboratory Estácio de Sá University Nova Friburgo Brazil Electronics Department-EE/UFRJ Rio de Janeiro Brazil

The use of an electrical current for the evaluation of several physiological variables in the human body is not a recent technique but continues to awaken great interest in the research community. One of the greatest applications for such a technique is the study of body composition through bioimpedance, where generally a equipment with a tetrapolar array set of electrodes is used to realize the bioimpedance measurement. The aim of the present work is to show that the bioimpedance measured is normally sub-estimated and to develop a correction factor for such values. The comparison between the original bioimpedance values, obtained by commercial equipment, and their corrected values, in body composition evaluation, will be shown. Body composition tests were conducted on 10 male subjects. Besides the bioimpedance analysis, anthropometric measures consisting of height, weight and skinfold-thickness were also obtained from the subjects to allow an estimation of the body composition by anthropometric equations established in the literature. The comparison results point to a better correlation (Pearson coefficient, r = 0.9735) between the anthropometric estimated fat-free mass (FFM) and the estimated value by the corrected bioimpedance adjusted, when compared with the original ones Pearson coefficient, r = 0.9487.

关键词： Impedance measurement Electrodes Bioimpedance biomedical measurements Voltage Bioelectric phenomena Preamplifiers Current measurement biomedical engineering Physiology

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