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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Visibilização de artérias coronárias epicárdicas em imagens ecocardiográficas tridimensionais com contraste de microbolhas / Visualization of the epicardial coronary arteries in microbubble contrasted tri-dimensional echocardiographic images

Lage, Danilo Meneses 01 October 2010 (has links)
Com os avanços tecnológicos das últimas décadas, a ecocardiografia surgiu como uma alternativa de diagnóstico por imagem de relativo baixo custo, que não faz uso de energia ionizante ou radioativa. Recentemente, o advento dos agentes de contraste por microbolhas e dos transdutores matriciais tornou possível a visualização tridimensional da anatomia das artérias coronárias. Neste projeto, é proposta a avaliação de métodos de segmentação capazes de visibilizar as artérias coronárias epicárdicas em Imagens de ecocardiografias tridimensionais com contraste de microbolhas. Esse é o primeiro passo para o desenvolvimento de ferramentas computacionais eficazes e eficientes na assistência não invasiva ao acompanhamento do quadro clínico de pacientes, do diagnóstico ao pós-operatório. Propõe-se, uma metodologia que facilite o acesso às coronárias a partir de imagens de ecocardiografia tridimensionais com aplicação de contraste por microbolhas. Dentre as metodologias estudadas, as técnicas baseadas na teoria Fuzzy Connectedness (FC) foram identificadas como as mais promissoras. Estudou-se, portanto, seis abordagens baseadas nessa teoria, três delas são descritas na literatura (Generalized FC GFC; Relative FC RFC; Dynamic Weighted FC DyWFC) e três proposições originais (Area of Search FC ASFC; Ultrasound-k FC USFC; Guided FC GuFC). Para avaliar a acurácia desses algoritmos, confeccionou-se um conjunto de imagens simuladas, composto por 360 imagens, e selecionou-se um conjunto de imagens de exames reais, composto de 10 imagens reais de pacientes com quadro de Cardiomiopatia Hipertrópica. Para as imagens simuladas, os métodos da literatura alcançaram acurácia de 85,5% para GFC, 89,5% para RFC e 92,0% para DyWFC. Enquanto isso, os métodos propostos alcançaram acurácia de 88,9% para ASFC, 91,7 % para USkFC e 95,2% para GuFC. Para as imagens reais, os métodos convergiram para uma segmentação satisfatória quanto à usabilidade na clínica médica. Esses resultados demonstraram, ainda, o melhor desempenho do método proposto GuFC ante os demais. Dessa forma, ele se torna um candidato para ingressar na etapa de segmentação de uma ferramenta computacional para visibilização das coronárias epicárdicas no futuro / With the technological advances of recent decades, echocardiography has emerged as a relatively low cost imaging diagnostic alternative, that does not use ionizing or radioactive energy. Lately, the advent of microbubble-based contrast agents and array transducers turned possible the visualization of three-dimensional coronary arteries anatomy. The present project proposes to evaluate segmentation methods able to deal with the visualization of the epicardial coronary arteries in microbubble-based three-dimensional echocardiography images. This is the first step towards the development of effective and efficient computational tools for diagnosis and prognosis assistance of cardiac pacient. We propose a methodology to facilitate the access to epicardial coronary arteries in tridimensional echocardiographic images. Among the studied approaches, Fuzzy Connectednessbased segmentation methods were identified as being the most promising. We studied six approaches based on this theory, three of them are described in the literature (Generalized FC GFC; Relative FC RFC; Dynamic Weighted FC DyWFC) and three original contributions (Area of Search FC ASFC; Ultrasound-k FC USFC; Guided FC GuFC). To evaluate the accuracy of these algorithms, a set composed of 360 simulated images were created. We also selected a set of 10 real images, composed of hypertrophic cardiomyopathy patients. For simulated images set, the methods of literature achieved accuracy of 85.5% for GFC, 89,5% for RFC and 92,0% for DyWFC, meanwhile, the proposed method achieved accuracy of 88.9% for ASFC, 91,7 % for USkFC and 95,2% for GuFC. Using the real images set, the methods converged to good results for clinical purposes. These results demonstrate that the proposed method GuFC has shown a better performance than the others, becoming a candidate to the segmentation step in a computational tool for coronary arteries visualization in the future
52

Fototerapia como estímulo à cicatrização de úlceras cutâneas em ratos nutridos e desnutridos / Phototherapy as stimulus for healing of cutaneous wounds in nourished and undernourished rats

Leite, Saulo Nani 19 June 2009 (has links)
O estudo avaliou a influência de diversas formas de fototerapia na cicatrização de úlceras cutâneas de ratos nutridos e desnutridos (desnutrição induzida). No 1º experimento, de 60 ratos Wistar sob controle dietético, 30 foram selecionados aleatoriamente, recebendo metade da dieta diária para indução de desnutrição (marasmo), confirmada pela perda de massa corporal, sinais clínicos e dosagem de albumina sérica. Os animais nutridos (N) e desnutridos (D) foram distribuídos em grupos (n=10) conforme tratamento fototerápico, a saber: aparelhos desligados (LED e laser - sham) e ligados (4 LED\'s 660 nm e 32 LED\'s 890 nm, 500 mW; e laser HeNe 632,8 nm, 3 mW), sendo designados GNS, GNL, GNH, GDS, GDL e GDH, respectivamente. Duas úlceras cutâneas foram realizadas com punch 8 mm e irradiadas 3 vezes por semana durante 14 dias. Os programas LAS e Photoshop foram utilizados para análise histológica (HE) da espessura da pele após o período de desnutrição, e o ImageJ para análise das imagens e cálculo do índice de cicatrização das úlceras no 7º e 14º dias, além da análise histológica (tricrômio de Gomori) para avaliação da colagênese após a desnutrição e no 14º pós-operatório. No 2º experimento 30 ratos receberam dieta controle e 30 receberam dieta normoprotéica associada à proteína de baixa qualidade (gelatina) para induzir desnutrição. A distribuição dos animais em grupos foi semelhante ao experimento 1, porém utilizando o aparelho de laser de diodo (L1 660 nm e L2 808 nm, 100 mW), sendo designados GNS, GNL1, GNL2, GDS, GDL1 e GDL2, respectivamente. A confirmação da desnutrição, o procedimento cirúrgico, protocolo de tratamento e as análises de imagens e histológicas seguiram a mesma metodologia do experimento 1. Os resultados do experimento 1 mostraram que após o período de desnutrição, a espessura da derme dos animais desnutridos apresentou-se menor (p<0,0001) em relação aos nutridos, assim como o percentual da ) colagênese (p<0,0005). No 7º dia pós-operatório as úlceras do GDS apresentaram menores ICU\'s em relação aos GNS (p<0,01), GDL (p<0,001) e GDH (p<0,05). No 14º dia, as úlceras do GNS apresentaram maiores ICU\'s em relação ao GNH e GDS (p<0,05) e GDH (p<0,01), assim como as do GDL em relação ao GDH (p<0,05). Histologicamente, o GDS apresentou menor percentual de colágeno em relação ao GNS (p<0,05), GNH, GDL e GDH (p<0,01). Os resultados do experimento 2 mostraram que após a desnutrição, a espessura da derme dos animais desnutridos apresentou-se menor (p<0,0001) em relação aos nutridos, assim como o percentual da colagênese (p<0,03). No 7º dia, as úlceras do GDS apresentaram menores ICU\'s em relação aos demais grupos (p<0,001). No 14º dia não houve diferença entre os grupos (p<0,05). Histologicamente, o GDS apresentou menor percentual de colágeno que os demais grupos (p<0,001), e os grupos desnutridos tratados com laser apresentaram maior percentual de colágeno que os demais grupos (p<0,001). Os resultados evidenciaram a influência negativa da desnutrição na cicatrização, e que as diversas formas de fototerapia apresentaram efeito bioestimulador na cicatrização e colagênese nas úlceras cutâneas de ratos desnutridos em comparação à cicatrização natural e fotoestimulada nos grupos nutridos. / The study evaluated the influence of various forms of phototherapy in the healing of cutaneous wounds in nourished and undernourished rats (induced malnutrition). In the 1st experiment, from 60 rats under control diet, 30 were randomly selected to receive half of the daily diet for induction of malnutrition (marasmus), confirmed by loss of body weight, clinical signs and serum albumin. Nourished (N) and undernourished (U) animals have been distributed into groups (n=10) according phototherapic treatment, viz: off devices (LED and laser - sham) and on devices (4 LEDs 660 nm, 32 LEDs 890 nm, 500 mW, and HeNe laser 632.8 nm, 3 mW) and they were designed GNS, GNL, GNH, GUS, GUL and GUH, respectively. Two 8mm dorsal cutaneous wounds were punched and irradiated 3 times per week for 14 days. LAS and Photoshop softwares were used for histological analysis (HE) of the skin thickness after malnutrition time, and ImageJ for analysis of images to calculate the wound healing rate in 7th and 14th days, besides the histological analysis (Gomori trichrome) to calculate the colagenesis after the malnutrition time and in 14th post operative day. In the 2nd experiment 30 rats have received control diet and 30 received normal protein diet associated of low quality protein (gelatin) to induce malnutrition. The distribution of animals in groups was similar to experiment 1, but using a diode laser device (L1 660 nm and L2 808nm, 100 mW) and they were designed GNS, GNL1, GNL2, GDS, GDL1 and GDL2 respectively. The malnutrition status, the surgical proceeding, the protocol for treatment and analysis of histological images followed the same methods used in experiment 1. The results of experiment 1 showed that after malnutrition time, the thickness of the dermis in the undernourished animals was lower (p<0.0001) than nourished even as the percentage of coallagenesis (p<0.0005). In the 7th post operative day the wound healing rates were lower in the GUS than GNS (p<0.01), GUL (p<0.001) and GUH (p<0.05). In the 14th day, the WHRs were higher in the GNS than GNH, GUS (p<0.05) and GUH (p<0.05). Histologically, the GUS showed lower percentage of collagen than GNS (p<0.05), GNH, GUL and GUH (p<0.01). In experiment 2, the results showed that after malnutrition time, the thickness of the dermis of the undernourished animals was lower (p<0.0001) than nourished, as well as the percentage of collagenesis (p<0.03). In the 7th day, the WHRs were lower in the GUS than other groups (p<0.001). In 14th day there was no difference between groups (p<0.05). Histologically, the GUS presented lower percentage of collagen than the other groups (p<0.001), and the undernourished group treated with laser presented higher percentage of collagen than other groups (p<0.001). The results showed the negative influence of the malnutrition in the wound healing and that the various kinds of phototherapy presented biostimulator effect in the cutaneous wound healing and collagenesis in undernourished rats as compared to natural and photostimulated healing in the nourished groups.
53

A study on computer-aided diagnosis for wireless capsule endoscopy images. / CUHK electronic theses & dissertations collection

January 2008 (has links)
A feature extraction approach based on color is firstly proposed. Exploiting color histogram of an image, we can obtain distribution of different colors in images. Then we employ minimum distance classifier based on a new distance criterion to judge status of regions. In this section, we also validate benefits of WCE image enhancement to the proposed CAD system. / Finally, we propose a new approach of chrominance moment as another kind of feature to discriminate normal regions from abnormal regions, which makes full use of Tchebichef polynomials and HSI color space. This new feature extraction scheme preserves illumination invariance without numerical approximation. / In conclusion, this thesis investigates several major and challenging problems such as WCE images enhancement and feature extractions in CAD for WCE images, and proposes several novel schemes to solve those problems. Extensive experiments are reported to demonstrate effectiveness of the proposed algorithms. / Next, we investigate automatic diseases detection for WCE images to partially solve the second problem. In this part we explore different features that are suitable for detection of diseases from three viewpoints, i.e., color, texture and chromaticity, because clinicians mainly use these clues to diagnose. At the same time, we introduce their corresponding classifiers. / We further advance a new texture feature extraction method, curvelet based local binary pattern, to detect abnormal regions in WCE images. This method takes advantage of curvelet transform and local binary pattern to describe textural features of WCE images. / Wireless capsule endoscopy (WCE) is a state-of-the-art technology to diagnose gastrointestinal (GI) tract diseases without invasiveness. However, there exist two major problems concerning WCE images. One problem is that many images for diagnosis have rather low contrast and are noisy, which causes difficulties to diagnosis and also to computer-aided detection, so it is necessary to enhance these images. The other one is that the viewing process of video data per examination is very time consuming because of the great amount of video data. If we can use computerized methods to help the physicians detect some abnormal regions in WCE images, it will certainly reduce the burden of physicians. Focusing on these two goals, this thesis mainly studies some main challenging problems in computer-aided diagnosis (CAD) system for WCE images. To solve the first problem, we put forward an adaptive curvature strength diffusion method to enhance WCE images. Based on local characteristics analysis of WCE images, we propose a new concept of curvature strength. Then, we employ curvature strength diffusion to enhance WCE images with an adaptive choice of conductance parameter. Finally, we extend the curvature strength diffusion to color space since WCE images are color images. / Li, Baopu. / Adviser: Max Q. H. Meng. / Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3640. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 126-150). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.
54

The applications of image processing in biology and relevant data analysis.

January 2007 (has links)
Wang, Zexi. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 63-64). / Abstract --- p.i / Acknowledgement --- p.iii / Chapter 0 --- Introduction --- p.1 / Chapter 1 --- The Design of the Experiments --- p.4 / Chapter 1.1 --- Flies and the Devices --- p.5 / Chapter 1.2 --- Parameter Settings and Interested Information --- p.8 / Chapter 2 --- Video Processing --- p.11 / Chapter 2.1 --- "Videos, Computer Vision and Image Processing" --- p.11 / Chapter 2.2 --- Details in Video Processing --- p.14 / Chapter 3 --- Data Analysis --- p.20 / Chapter 3.1 --- Background --- p.20 / Chapter 3.2 --- Outline of Data Analysis in Our Project --- p.22 / Chapter 4 --- Effect of the Medicine --- p.25 / Chapter 4.1 --- Hypothesis Testing --- p.26 / Chapter 4.2 --- Two-sample t Test --- p.28 / Chapter 5 --- Significance of the Two Factors --- p.32 / Chapter 5.1 --- Background of ANOVA --- p.33 / Chapter 5.2 --- The Model of ANOVA --- p.35 / Chapter 5.3 --- Two-way ANOVA in Our Data Analysis --- p.42 / Chapter 6 --- Regression Model --- p.45 / Chapter 6.1 --- Background of Regression Analysis --- p.47 / Chapter 6.2 --- Polynomial Regression Models --- p.52 / Chapter 6.2.1 --- Background --- p.52 / Chapter 6.2.2 --- R2 and adjusted R2 --- p.53 / Chapter 6.3 --- Model Verification --- p.58 / Chapter 6.4 --- A Simpler Model As the Other Choice --- p.59 / Chapter 6.5 --- Conclusions --- p.60 / Chapter 7 --- Further Studies --- p.61 / Bibliography --- p.62
55

Calculation of scatter in cone beam CT : steps towards a virtual tomograph /

Malusek, Alexandr, January 2008 (has links)
Diss. (sammanfattning) Linköping : Linköpings universitet, 2008. / Härtill 5 uppsatser.
56

Evaluation of dose and image quality parameters for cone-beam CT localization protocols in radiation therapy

Jacome, Victor Roland. January 2009 (has links) (PDF)
Thesis--University of Oklahoma. / Bibliography: leaves 152-154.
57

Optimization of image quality and minimization of radiation dose for chest computed radiography

Kong, Xiang. January 2006 (has links) (PDF)
Thesis--University of Oklahoma. / Bibliography: leaves 69-70.
58

Fototerapia como estímulo à cicatrização de úlceras cutâneas em ratos nutridos e desnutridos / Phototherapy as stimulus for healing of cutaneous wounds in nourished and undernourished rats

Saulo Nani Leite 19 June 2009 (has links)
O estudo avaliou a influência de diversas formas de fototerapia na cicatrização de úlceras cutâneas de ratos nutridos e desnutridos (desnutrição induzida). No 1º experimento, de 60 ratos Wistar sob controle dietético, 30 foram selecionados aleatoriamente, recebendo metade da dieta diária para indução de desnutrição (marasmo), confirmada pela perda de massa corporal, sinais clínicos e dosagem de albumina sérica. Os animais nutridos (N) e desnutridos (D) foram distribuídos em grupos (n=10) conforme tratamento fototerápico, a saber: aparelhos desligados (LED e laser - sham) e ligados (4 LED\'s 660 nm e 32 LED\'s 890 nm, 500 mW; e laser HeNe 632,8 nm, 3 mW), sendo designados GNS, GNL, GNH, GDS, GDL e GDH, respectivamente. Duas úlceras cutâneas foram realizadas com punch 8 mm e irradiadas 3 vezes por semana durante 14 dias. Os programas LAS e Photoshop foram utilizados para análise histológica (HE) da espessura da pele após o período de desnutrição, e o ImageJ para análise das imagens e cálculo do índice de cicatrização das úlceras no 7º e 14º dias, além da análise histológica (tricrômio de Gomori) para avaliação da colagênese após a desnutrição e no 14º pós-operatório. No 2º experimento 30 ratos receberam dieta controle e 30 receberam dieta normoprotéica associada à proteína de baixa qualidade (gelatina) para induzir desnutrição. A distribuição dos animais em grupos foi semelhante ao experimento 1, porém utilizando o aparelho de laser de diodo (L1 660 nm e L2 808 nm, 100 mW), sendo designados GNS, GNL1, GNL2, GDS, GDL1 e GDL2, respectivamente. A confirmação da desnutrição, o procedimento cirúrgico, protocolo de tratamento e as análises de imagens e histológicas seguiram a mesma metodologia do experimento 1. Os resultados do experimento 1 mostraram que após o período de desnutrição, a espessura da derme dos animais desnutridos apresentou-se menor (p<0,0001) em relação aos nutridos, assim como o percentual da ) colagênese (p<0,0005). No 7º dia pós-operatório as úlceras do GDS apresentaram menores ICU\'s em relação aos GNS (p<0,01), GDL (p<0,001) e GDH (p<0,05). No 14º dia, as úlceras do GNS apresentaram maiores ICU\'s em relação ao GNH e GDS (p<0,05) e GDH (p<0,01), assim como as do GDL em relação ao GDH (p<0,05). Histologicamente, o GDS apresentou menor percentual de colágeno em relação ao GNS (p<0,05), GNH, GDL e GDH (p<0,01). Os resultados do experimento 2 mostraram que após a desnutrição, a espessura da derme dos animais desnutridos apresentou-se menor (p<0,0001) em relação aos nutridos, assim como o percentual da colagênese (p<0,03). No 7º dia, as úlceras do GDS apresentaram menores ICU\'s em relação aos demais grupos (p<0,001). No 14º dia não houve diferença entre os grupos (p<0,05). Histologicamente, o GDS apresentou menor percentual de colágeno que os demais grupos (p<0,001), e os grupos desnutridos tratados com laser apresentaram maior percentual de colágeno que os demais grupos (p<0,001). Os resultados evidenciaram a influência negativa da desnutrição na cicatrização, e que as diversas formas de fototerapia apresentaram efeito bioestimulador na cicatrização e colagênese nas úlceras cutâneas de ratos desnutridos em comparação à cicatrização natural e fotoestimulada nos grupos nutridos. / The study evaluated the influence of various forms of phototherapy in the healing of cutaneous wounds in nourished and undernourished rats (induced malnutrition). In the 1st experiment, from 60 rats under control diet, 30 were randomly selected to receive half of the daily diet for induction of malnutrition (marasmus), confirmed by loss of body weight, clinical signs and serum albumin. Nourished (N) and undernourished (U) animals have been distributed into groups (n=10) according phototherapic treatment, viz: off devices (LED and laser - sham) and on devices (4 LEDs 660 nm, 32 LEDs 890 nm, 500 mW, and HeNe laser 632.8 nm, 3 mW) and they were designed GNS, GNL, GNH, GUS, GUL and GUH, respectively. Two 8mm dorsal cutaneous wounds were punched and irradiated 3 times per week for 14 days. LAS and Photoshop softwares were used for histological analysis (HE) of the skin thickness after malnutrition time, and ImageJ for analysis of images to calculate the wound healing rate in 7th and 14th days, besides the histological analysis (Gomori trichrome) to calculate the colagenesis after the malnutrition time and in 14th post operative day. In the 2nd experiment 30 rats have received control diet and 30 received normal protein diet associated of low quality protein (gelatin) to induce malnutrition. The distribution of animals in groups was similar to experiment 1, but using a diode laser device (L1 660 nm and L2 808nm, 100 mW) and they were designed GNS, GNL1, GNL2, GDS, GDL1 and GDL2 respectively. The malnutrition status, the surgical proceeding, the protocol for treatment and analysis of histological images followed the same methods used in experiment 1. The results of experiment 1 showed that after malnutrition time, the thickness of the dermis in the undernourished animals was lower (p<0.0001) than nourished even as the percentage of coallagenesis (p<0.0005). In the 7th post operative day the wound healing rates were lower in the GUS than GNS (p<0.01), GUL (p<0.001) and GUH (p<0.05). In the 14th day, the WHRs were higher in the GNS than GNH, GUS (p<0.05) and GUH (p<0.05). Histologically, the GUS showed lower percentage of collagen than GNS (p<0.05), GNH, GUL and GUH (p<0.01). In experiment 2, the results showed that after malnutrition time, the thickness of the dermis of the undernourished animals was lower (p<0.0001) than nourished, as well as the percentage of collagenesis (p<0.03). In the 7th day, the WHRs were lower in the GUS than other groups (p<0.001). In 14th day there was no difference between groups (p<0.05). Histologically, the GUS presented lower percentage of collagen than the other groups (p<0.001), and the undernourished group treated with laser presented higher percentage of collagen than other groups (p<0.001). The results showed the negative influence of the malnutrition in the wound healing and that the various kinds of phototherapy presented biostimulator effect in the cutaneous wound healing and collagenesis in undernourished rats as compared to natural and photostimulated healing in the nourished groups.
59

Visibilização de artérias coronárias epicárdicas em imagens ecocardiográficas tridimensionais com contraste de microbolhas / Visualization of the epicardial coronary arteries in microbubble contrasted tri-dimensional echocardiographic images

Danilo Meneses Lage 01 October 2010 (has links)
Com os avanços tecnológicos das últimas décadas, a ecocardiografia surgiu como uma alternativa de diagnóstico por imagem de relativo baixo custo, que não faz uso de energia ionizante ou radioativa. Recentemente, o advento dos agentes de contraste por microbolhas e dos transdutores matriciais tornou possível a visualização tridimensional da anatomia das artérias coronárias. Neste projeto, é proposta a avaliação de métodos de segmentação capazes de visibilizar as artérias coronárias epicárdicas em Imagens de ecocardiografias tridimensionais com contraste de microbolhas. Esse é o primeiro passo para o desenvolvimento de ferramentas computacionais eficazes e eficientes na assistência não invasiva ao acompanhamento do quadro clínico de pacientes, do diagnóstico ao pós-operatório. Propõe-se, uma metodologia que facilite o acesso às coronárias a partir de imagens de ecocardiografia tridimensionais com aplicação de contraste por microbolhas. Dentre as metodologias estudadas, as técnicas baseadas na teoria Fuzzy Connectedness (FC) foram identificadas como as mais promissoras. Estudou-se, portanto, seis abordagens baseadas nessa teoria, três delas são descritas na literatura (Generalized FC GFC; Relative FC RFC; Dynamic Weighted FC DyWFC) e três proposições originais (Area of Search FC ASFC; Ultrasound-k FC USFC; Guided FC GuFC). Para avaliar a acurácia desses algoritmos, confeccionou-se um conjunto de imagens simuladas, composto por 360 imagens, e selecionou-se um conjunto de imagens de exames reais, composto de 10 imagens reais de pacientes com quadro de Cardiomiopatia Hipertrópica. Para as imagens simuladas, os métodos da literatura alcançaram acurácia de 85,5% para GFC, 89,5% para RFC e 92,0% para DyWFC. Enquanto isso, os métodos propostos alcançaram acurácia de 88,9% para ASFC, 91,7 % para USkFC e 95,2% para GuFC. Para as imagens reais, os métodos convergiram para uma segmentação satisfatória quanto à usabilidade na clínica médica. Esses resultados demonstraram, ainda, o melhor desempenho do método proposto GuFC ante os demais. Dessa forma, ele se torna um candidato para ingressar na etapa de segmentação de uma ferramenta computacional para visibilização das coronárias epicárdicas no futuro / With the technological advances of recent decades, echocardiography has emerged as a relatively low cost imaging diagnostic alternative, that does not use ionizing or radioactive energy. Lately, the advent of microbubble-based contrast agents and array transducers turned possible the visualization of three-dimensional coronary arteries anatomy. The present project proposes to evaluate segmentation methods able to deal with the visualization of the epicardial coronary arteries in microbubble-based three-dimensional echocardiography images. This is the first step towards the development of effective and efficient computational tools for diagnosis and prognosis assistance of cardiac pacient. We propose a methodology to facilitate the access to epicardial coronary arteries in tridimensional echocardiographic images. Among the studied approaches, Fuzzy Connectednessbased segmentation methods were identified as being the most promising. We studied six approaches based on this theory, three of them are described in the literature (Generalized FC GFC; Relative FC RFC; Dynamic Weighted FC DyWFC) and three original contributions (Area of Search FC ASFC; Ultrasound-k FC USFC; Guided FC GuFC). To evaluate the accuracy of these algorithms, a set composed of 360 simulated images were created. We also selected a set of 10 real images, composed of hypertrophic cardiomyopathy patients. For simulated images set, the methods of literature achieved accuracy of 85.5% for GFC, 89,5% for RFC and 92,0% for DyWFC, meanwhile, the proposed method achieved accuracy of 88.9% for ASFC, 91,7 % for USkFC and 95,2% for GuFC. Using the real images set, the methods converged to good results for clinical purposes. These results demonstrate that the proposed method GuFC has shown a better performance than the others, becoming a candidate to the segmentation step in a computational tool for coronary arteries visualization in the future
60

Efeitos da utilização de  insulina e de um implante transitório de biomembrana de látex natural, derivado da seringueira Hevea brasiliensis, em um modelo experimental de perfuração traumática de membrana timpânica / Effects of the treatment using insulin and a transitory natural latex biomembrane implant from rubber tree Hevea brasiliensis, in an experimental model of traumatic perforation of tympanic membrane

Marcos Miranda de Araújo 07 December 2012 (has links)
Nos últimos anos, houve uma tendência na busca por substâncias reguladoras que pudessem otimizar o processo de cicatrização de membranas timpânicas (MTs) perfuradas. Objetivos: Determinar os efeitos da utilização da insulina tópica e da biomembrana de látex natural, de forma isolada e em associação, no processo de cicatrização de perfurações traumáticas de MTs. Materiais e Métodos: MTs de 61 ratos Wistar foram perfuradas nas porções anterior e posterior ao cabo do martelo. Os animais foram divididos em quatro grupos: Controle, Insulina, Látex e Insulina+Látex. No grupo Insulina, as perfurações foram tratadas com uso tópico de insulina regular. No grupo Látex, tratadas com biomembrana de látex natural. No grupo Insulina+Látex, tratadas com associação da insulina e da biomembrana de látex. As MTs foram avaliadas por técnicas histológicas com três, cinco e sete dias após sua perfuração traumática. Foram analisadas as morfometrias das espessuras das camadas epitelial, fibrosa e mucosa; tamanho da perfuração; área de secção transversal da MT; avaliação semiquantitativa e qualitativa da produção de colágeno por microscopia de polarização; e avaliação imuno-histoquímica das células epiteliais, dos miofibroblastos e da vascularização. Resultados: A insulina e a biomembrana de látex anteciparam o fechamento das perfurações traumáticas de MTs (p<0,01); estimularam precocemente o aumento da espessura da camada epitelial externa (p<0,01); promoveram aumento precoce da espessura da camada fibrosa (p<0,01); contribuíram para a maior identificação do anticorpo anti-panqueratina como marcador epitelial (p<0,05); aumentaram a marcação do anticorpo anti-alfa-actina de músculo liso (p<0,05), caracterizando maior proliferação de miofibroblastos. A insulina, isoladamente, provocou maior formação do colágeno tecidual (p<0,05), com fibras colágenas mais espessas e melhor organizadas (p<0,05). Conclusão: A insulina e a biomembrana de látex natural, de forma isolada e em associação, aceleraram o processo de cicatrização de perfurações traumáticas de MTs. / In recent years, there has been a tendency to search for regulatory substances that can optimize the healing process of perforated tympanic membranes (TMs). Objectives: To determine the effects of using topical insulin and natural latex biomembrane, alone or in combination, in the healing process of traumatic perforations of TMs. Methods: TMs of 61 Wistar rats were perforated in two sections, anterior and posterior to the malleus. The rats were divided into 4 groups: Control, Insulin, Latex, and Insulin+Latex. The Insulin group was treated with topical regular insulin. The Latex group was treated with natural latex biomembrane. The Insulin+Latex group was treated with a combination of insulin plus latex biomembrane. The TMs were histologically examined 3, 5, and 7 days post-perforation through morphometric analysis of the thickness of the epithelial, fibrous, and mucosal layers; size of the perforation; cross sectional area of the TM; semiquantitative and qualitative evaluation of the collagen production by polarization microscopy, and immunohistochemical evaluation of epithelial cells, myofibroblasts, and vascularization markers. Results: Insulin and latex biomembrane accelerated the healing process of the perforated TMs (p<0.01); stimulated early thickening of the outer epithelial layer (p<0.01); promoted premature increase in the thickness of the fibrous layer (p<0.01); contributed to a larger identification of anti-pankeratin antibody as epithelial marker (p<0.05); increased labeling of anti-alpha smooth muscle actin antibody (p<0.05), indicating greater proliferation of myofibroblasts. When insulin was used alone, it resulted in greater formation of collagen tissue (p<0.05), with thicker and better-organized collagen fibers (p<0.05). Conclusion: Insulin and natural latex biomembrane, used alone or in combination, accelerated the healing process of traumatic perforations of TMs.

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