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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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Principal components of frequency domain electromyograms for muscular fatigue analysis

Principal components of frequency domain electromyograms for...

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

作者： Igor Ramathur Telles de Jesus Roger G. T. Mello Jurandir Nadal Biomedical Engineering Program COPPE Federal University of Rio de Janeiro Rio de Janeiro Brazil Sport and Physical Education Department Naval Postgraduate School Brasilia Brazil

The parameters commonly employed for muscular fatigue (MF) analysis, the mean frequency (F mean ) and median frequency (F median ) of surface EMG (SEMG) spectra, did not present consistent results for exercises performed at low to moderate intensities. For overcoming this limitation, the present study proposes the use of principal component (PC) analysis of SEMG spectra for MF monitoring. The SEMG from vastus lateralis muscle of 24 young male subjects were recorded during a maximal effort test in cycle ergometer. Epochs of 200 ms SEMG, extracted from each period of muscle activation of each subject were used for estimating the amplitude spectra, which were employed to obtain the first two PCs. The PC coefficients from the first 40 spectra were used as a reference for calculating the standard distance. This index presented a consistent increase along the exercise, while the values of F mean and F median did not present any pattern. Comparisons between initial and final values from all subjects show no significant changes in F mean and F median (Student t test, P > 0.05) and a significant increase (P≪10 -3 ) in standard distance, indicating this index as an alternative to MF analysis in cyclical exercises.

关键词： Fatigue Muscles Indexes Principal component analysis Electromyography Protocols Digital filters

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Evaluation of the influence of large temperature variations on the grey level content of B-mode images

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Physics Procedia 2010年第1期3卷 415-419页

作者： André V. Alvarenga César A. Teixeira Maria Graça Ruano Wagner C.A. Pereira Laboratory of Ultrasound/National Institute of Metrology Standardization and Industrial Quality (Inmetro) Duque de Caxias Brazil Centre for Intelligent Systems/University of Algarve Faro Portugal Biomedical Engineering Program/COPPE Federal University of Rio de Janeiro Rio de Janeiro Brazil

In this work, the variation of the grey-level content of B-Mode images is assessed, when the medium is subjected to large temperature variations. The goal is to understand how the features obtained from the grey-level pattern can be used to improve the actual state-of-the-art methods for non-invasive temperature estimation (NITE). Herein, B-Mode images were collected from a tissue mimic phantom heated in a water bath. Entropy was extracted from image Grey-Level Co-occurrence Matrix, and then assessed for non-invasive temperature estimation. During the heating period, the average temperature varies from 27 ∘ C to 44 ∘ C, and entropy values were capable of identifying variations of 2.0 ∘ C. Besides, it was possible to quantify variations in the range from normal human body temperature (37 ∘ C) to critical values, as 41 ∘ C. Results are promising and encourage us to study the uncertainty associated to the experiment trying to improve the parameter sensibility.

关键词： Non-invasive temperature estimation Grey-level content Image processing techniques Ultrasound

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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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Localized fatigue effects on quiet standing control by fractional Brownian motion

Localized fatigue effects on quiet standing control by fract...

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

作者： Roger G. T. Mello Liliam F. Oliveira Jurandir Nadal Sport and Physical Education Department Naval Postgraduate School Brasilia Brazil Biomechanics Laboratory School of Physical Education and Sports Federal University of Rio de Janeiro Brazil Biomedical Engineering Program COPPE Federal University of Rio de Janeiro Rio de Janeiro Brazil

In this work, the anterior-posterior displacement of the center of pressure was modeled as a fractional Brownian motion to analyze the effect of fatigue of plantar flexor muscles by isometric contraction. A sample of 17 young, healthy adults was evaluated by stabilometric test, 2 min before and after a plantar flexion, sustained until exhaustion. For each test, the model was applied to four consecutive periods of 30 s and then averaged to estimate the parameters. The fatigue increased the stochastic activity in both persistent and antipersistent controls, and also increased the Hurst exponent of the long-term mechanism. As a conclusion, the used model suggests that peripheral fatigue increases the body sway and reduces the gain of the antipersistent mechanism. However, these changes are detectable only when more than one 30 s data segment is considered for analysis.

关键词： Fatigue Brownian motion Correlation Muscles Mathematical model Stochastic processes Force

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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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Breast ultrasound phantom for image segmentation assessment

Breast ultrasound phantom for image segmentation assessment

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2009 IEEE International Ultrasonics Symposium, IUS 2009

作者： De Carvalho, Isabela Miller Basto, Rodrigo Leite Q. Infantosi, Antonio Fernando C. Von Krüger, Marco Antonio Pereira, Wagner Coelho De A. Biomedical Engineering Program - COPPE Federal University of Rio de Janeiro Rio de Janeiro Brazil

ISBN: (纸本)9781424443895

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 regular shape, which is a typical feature related to non malignancy. The phantom matrix was made of a mixture of water, agar, glycerin and graphite and PVC powders and the lesions were of polyacrylamide. The mimicking properties were US attenuation, propagation speed and density. The regularity of the edge lesions was evaluated using two morphometric parameters: (1) Overlap Ratio (RS), and (2) Normalized Residual Mean square value (nrv). They were found compatible with regular contours of real lesions. ©2009 IEEE.

关键词： Ultrasonics

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Characterization of cutaneous cell carcinomas by ultrasound biomicroscopy

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Physics Procedia 2010年第1期3卷 761-765页

作者： L.I. Petrella J.C. Martins H.A. Valle P.R. Issa W.C.A. Pereira J.C. Machado Biomedical Engineering Program COPPE Federal University of Rio de Janeiro Av. Horacio Macedo 2030 Rio de Janeiro 21941-914 Brazil Dermatology Sector HUGG State Federal University of Rio de Janeiro Av. Mariz e Barros 775 Rio de Janeiro 20270-004 Brazil Pathologic Anatomy Sector HUGG State Federal University of Rio de Janeiro Av. Mariz e Barros 775 Rio de Janeiro 20270-004 Brazil

The potential of ultrasound biomicroscopy (UBM) images to evidence the alterations occurring in skin tissues affected by cutaneous carcinomas was studied. The histological patterns associated to these carcinomas can vary considerably between patients, involving diverse atypical tissue constituents which should be identified in UBM images, considering the perspective of applying this technique as a diagnostic tool. The study was conducted using in vitro fresh human tissue samples, obtained from biopsied volunteer patients. The UBM images were generated as in the conventional B-mode, and acquired with an experimental system working in a fundamental frequency of 45 MHz. Distinct tissues constituents, normal or pathologic, were identified in the UBM images by variations in the image brightness level, and could be observed in most of the studied cases. Moreover, the brightness characteristics associated to each tissue constituent seem to repeat along the different studied samples. Although the differentiation between the diverse structures was possible by a qualitative analysis, additional quantitative techniques (related to tissue acoustic, statistical and spectral properties) are been implemented, to improve the UBM diagnostic capability.

关键词： Cutaneous carcinomas Images Ultrasonic biomicroscopy

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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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Preliminary study of pseudoarthrosis ultrasonic characterization

Preliminary study of pseudoarthrosis ultrasonic characteriza...

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2009 IEEE International Ultrasonics Symposium, IUS 2009

作者： Matusin, Daniel Patterson Pereira, Wagner Coelho De A. Machado, Christiano Bittencourt Ferreira, Manoel L. Schanaider, Alberto Biomedical Engineering Program - COPPE Federal University of Rio de Janeiro Rio de Janeiro Brazil Experimental Surgery Department - CCS Federal University of Rio de Janeiro Rio de Janeiro Brazil

ISBN: (纸本)9781424443895

Pseudoarthosis is a consequence of a failure in bone fracture healing process, resulting in a non-union and relative motion between fragments. The evolution of fracture consolidation and the diagnosis of pseudoarthrosis have often a follow-up with conventional X-rays exams. Quantitative ultrasound (US) characterization has the advantage of being a non-ionizing energy and of low cost. A pulse-echo substitution method to characterize biological tissues by backscattered US was implemented. Pseudoarthrosis characterization was made by parameters Apparent Integrated Backscatter - AIB, Frequency Slope Apparent Backscatter - FSAB and Time Slope Apparent Backscatter - TSAB. Initials results have shown that parameters AIB and FSAB were able to differentiate normal from pseudoarthrotic tissues with statistical significance. Additional experiments with a greater number of samples are to be made, as well as some methodological adjustments aiming in vivo applications. ©2009 IEEE.

关键词： Ultrasonics

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