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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.
1

Introduction of a pictorial poster and a 'crash course' of radiographic errors for improving the qualityof paediatric chest radiographs in an unsupervised unit

Hlabangana, Linda Tebogo 10 February 2014 (has links)
A research report submitted to the Faculty of Health Sciences, University of the Witwatersrand in fulfillment for the degree of Master of Medicine in the branch of Diagnostic Radiology / Chest radiography is the most commonly performed diagnostic X-ray examination. Optimised image quality is important, particularly in children with radio-sensitive immature organs.
2

Quantifying image quality in diagnostic radiology using simulation of the imaging system and model observers /

Ullman, Gustaf, January 2008 (has links) (PDF)
Diss. (sammanfattning) Linköping : Linköpings universitet, 2008. / Härtill 6 uppsatser. Includes bibliographical references.
3

Quantifying image quality in diagnostic radiology using simulation of the imaging system and model observers /

Ullman, Gustaf, January 2008 (has links) (PDF)
Diss. (sammanfattning) Linköping : Linköpings universitet, 2008. / Härtill 6 uppsatser.
4

A method for in-treatment measurement of residual respiratory motion of organs for stereotactic body radiation therapy

Pater, Piotr. January 1900 (has links)
Thesis (M.Sc.). / Written for the Medical Physics Unit. Title from title page of PDF (viewed ). Includes bibliographical references.
5

Ultrasonografija pluća kao dijagnostička metoda u neonatalnoj intenzivnoj jedinici / Lung ultrasound as a diagnostic method in the Neonatal intensive care unit

Petković Mirjana 28 September 2017 (has links)
<p>Uvod: Značajno mesto u morbiditetu nedono&scaron;čadi predstavljaju plućne bolesti. Ultrazvučnim (UZ) pregledom pluća može se smanjiti ukupna doza jonizujućeg zračenja kojoj su nedono&scaron;čad izložena u svakodnevnom kliničkom radu. Cilj: Ispitati povezanost između UZ nalaza na plućima i RTG nalaza i kliničkih parametara respiratornog statusa kod nedono&scaron;čadi. Utvrditi da li se UZ-om detektovane subpleuralne konsolidacije mogu morfolo&scaron;ki diferencirati. Utvrditi da li UZ nalaz na plućima pomaže neonatologu u proceni efekta terapije tokom lečenja nedono&scaron;čadi. Materijal i metode: Prospektivnim tipom jednogodi&scaron;njeg istraživanja obuhvaćeno je 100 nedono&scaron;čadi kojoj je nakon prijema na Odeljenje intenzivne nege i terapije (OINT) bio indikovan RTG snimak pluća. Za izvođenje UZ pregleda pluća kori&scaron;ćeni su Siemens Sonoline Adara i Siemens Sonoline Sienna UZ aparati. Kori&scaron;ćena je siva skala i konveksna sonda (5 MHz) i linearna sonda (7,5 MHz). Za ispitivanje korelacije između UZ nalaza na plućima i kliničkih parametara respiratornog statusa (FiO2, PCO2, SaO2) kori&scaron;ćen je Pearson-ov koeficijent korelacije. Posebno je ispitivana korelacija kod nedono&scaron;čadi koja su bila na mehaničkoj ventilaciji (MV) i kod nedono&scaron;čadi koja su bila na oksigenoterapiji (OxTh). Utvrđivanje razlika između UZ-om uočenih konsolidacija i RTG-om uočenih konsolidacija, urađeno je prebrojavanjem ukupnog broja uočenih konsolidacija svakom od dve navedene radiolo&scaron;ke metode i poređenjem prosečnog broja uočenih konsolidacija UZ-om, odnosno RTG-om. U svim statističkim testovima je kori&scaron;ćen je nivo značajnosti p&lt;0,05 i interval poverenja (CI) 95%. Rezultati: Kod nedono&scaron;čadi koja su bila na MV, kao i kod nedono&scaron;čadi na OxTh, postoji statistički značajna korelacija između UZ nalaza na plućima i kliničkih parametara respitatornog statusa (p&lt;0,001). Kod bolesnika na MV procenat podudaranja, odnosno nepodudaranja UZ nalaza i FiO2 iznosio je 81%, odnosno 19%. Procenat podudaranja, odnosno nepodudaranja UZ nalaza i PCO2 je bio 80%, odnosno 20%, dok je u slučaju SaO2 procenat podudaranja sa UZ nalazom bio 80%, a nepodudaranja 20%. Kod nedono&scaron;čadi na MV, procenat podudarnosti UZ nalaza na plućima i sva tri klinička parametra zabeležen je u 68%, sa dva klinička parametra u 21%, dok je u 11% zabeležena podudarnost samo sa jednim kliničkim parametrom. Kod nedono&scaron;čadi koja su bila na OxTh procenat podudaranja, odnosno nepodudaranja UZ nalaza i FiO2 iznosio je 94%, odnosno 6%. Procenat podudaranja, odnosno nepodudaranja UZ nalaza i PCO2 je bio 94%, odnosno 6%, dok je u slučaju SaO2 procenat podudaranja sa UZ nalazom bio 93%, a nepodudaranja 7%. Kod nedono&scaron;čadi na OxTh procenat podudarnosti UZ nalaza na plućima i sva tri klinička parametra zabeležen je u 85%, sa dva klinička parametra u 10%, dok je u 5% zabeležena podudarnost samo sa jednim kliničkim parametrom. Prosečan broj UZ-om uočenih konsolidacija po svakom pojedinačnom UZ pregledu pluća je bio 0,80, dok ih je na pojedinačnom RTG snimku uočeno 0,25. U 29% slučajeva konsolidacije su istovremeno uočene i UZ i RTG pregledom pluća, dok je u 71% slučajeva konsolidacije bilo moguće otkriti samo UZ pregledom pluća. Od ukupno 304 subpleuralnih konsolidacija koje su uočene UZ-om, u 172 slučaja (56,58%) je na osnovu prethodno klinički i/ili laboratorijski postavljene dijagnoze indirektno utvrđeno poreklo konsolidacije: u 125 slučajeva (72,67%) uzrok je bio atelektaza, u 39 slučajeva (22,67%) neonatalna pneumonija i u 8 slučajeva (4,66%) plućna hemoragija. Zaključci: Postoji statistički značajna korelacija između ultrazvučnog nalaza na plućima nedono&scaron;čadi i kliničkih parametara respiratornog statusa - FiO2, PaCO2 i SaO2, kako kod nedono&scaron;čadi na MV, tako i kod nedono&scaron;čadi na OxTh, zbog čega ultrazvučni nalaz na plućima može biti od pomoći neonatologu u praćenju efekta primenjene terapije. Na osnovu karakteristika ultrazvučno uočenih subpleuralnih konsolidacija nije moguće utvrditi njihovu etiologiju, već samo u korelaciji sa kliničkim i laboratorijskim nalazima. Ultrazvuk pluća je senzitivnija metoda za uočavanje subpleuralnih konsolidacija u odnosu na radiografiju pluća.</p> / <p>Introduction: Lung diseases play a major role in morbidity of premature neonates. Using lung ultrasound (LUS) as a diagnostic tool lowers the dose of ionizing radiation of prematures in every day clinical work. Objectives: To assay the interconnection between LUS and chest X ray (CXR) and clinical parameters of respiratory status (FiO2, PCO2 i SaO2) in prematures. To investigate the possibility of sonographic determination of etiology of subpleural consolidations based on their appearance. To determine whether LUS can be of clinical benefit to the neonatologist in assessing the effect of therapy used in treating prematures. Material and methods: Prospective one year study included 100 premature neonates who underwent a CXR exam after the admission in the Intensive care unit (ICU). Siemens Sonoline Adara i Siemens Sonoline Sienna US machines were used, as well as the gray scale, convex probe (5 MHz) and linear probe (7,5 MHz). Pearson correlation coefficient was used to test the interconnection between LUS and clinical parameters of respiratory status (FiO2, PCO2, SaO2). The test was performed separately for both prematures on mechanical ventilation (MV) and prematures on oxygen therapy (OxTh). Determination of differencies between consolidations seen on LUS and those seen on CXR was done by counting the number of consolidation detected with each method and by comparing the average number of consolidations detected with LUS and by CXR. The assessment of statistical significance was done using the p value, and the p value&lt;0,05 and the confidence interval (CI) of 95% was considered as statistically significant. Results: Statistically significant correlation (p&lt;0,001) was established between clinical parameters of respiratory status and LUS both in prematures on MV and on OxTh. The percentage of concurrence, or nonconcurrence of LUS and FiO2 was 81% and 19% (respectively). The percentage of concurrence, or nonconcurrence of LUS and PCO2 was 80% and 20% (respectively), while in case of SaO2 the percentage of concurrence with LUS was also 80% and the percentage of nonconcurrence was 20%. In the group of prematures on MV the percentage of concurrence of LUS with all three clinical parameters was in 68%, with two parameters the concurrence was evident in 21% and with a single clinical parameter in 11%. In prematures on OxTh, the percentage of concurrence, or nonconcurrence of LUS and FiO2 was 94% and 6% (respectively). The percentage of concurrence, or nonconcurrence of LUS and PCO2 was also 96% and 4% (respectively), while in case of SaO2 the percentage of concurrence with LUS was also 93% and the percentage of nonconcurrence was 7%. In the group of prematures on OxTh the percentage of concurrence of LUS with all three clinical parameters was in 85%, with two parameters the concurrence was evident in 10% and with a single clinical parameter in 5%. The mean number of subpleural consolidations detected by LUS per exam was 0.80. The mean number of consolidations detected on each CXR was 0.25. In 29%&nbsp; consolidations were detected both with LUS and CXR, but in 71% consolidations were only detected using LUS. 304 subpleural consolidations were seen on LUS, but only in 172 cases (56.58%) it was possible to determine the etiology of consolidations and this was done indirectly, in concordance with previously clinically and/or laboratory diagnosis: in 125 cases (72.67%) the origin was atelectasis, in 39 cases (22.67%) neonatal pneumonia and in 8% (4.66%) pulmonary haemorrhage. Conclusion: Statistically significant interconnection between LUS and clinical parameters of respiratory status &ndash; FiO2, PaCO2 i SaO2 exists both in MV prematures and prematures with oxygen supplementation. Previously mentioned suggests that LUS can be of use to neonatologist in following the effect of administred therapy in prematures. The origin of subpleural consolidations cannot be determined on the basis of their appereance or features seen on LUS. The etiology of sonographic subpleural consolidations can only be indirectly determined in correlation with clinical and laboratory findings. LUS is more sensitive than CXR in detecting subpleural consolidations.</p>
6

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.
7

Prevención secundaria en estudiantes de medicina con familiares profesionales de la salud en una universidad privada de Lima, Perú / Secondary prevention in medical students with family health professionals in a private university in Lima, Peru

Reyes Cuestas, Ricardo Manuel 22 February 2021 (has links)
Introducción: La prevención significa reducir factores de riesgo, detener el avance de la enfermedad y atenuar sus consecuencias (OMS). En el 2006, no se encontró asociación entre los determinantes sociales en los estudiantes de medicina de una universidad peruana, y la promoción y prevención de la salud. Como objetivo se planteó determinar si existe asociación entre tener familiares profesionales de la salud y haberse realizado una radiografía de tórax, en el último año, en estudiantes de medicina de una universidad peruana. Material y métodos: Transversal analítico; que utilizó una ficha de recolección de datos, probada en piloto para calcular tamaño muestral. La población comprendió estudiantes de medicina de una universidad peruana. Se realizó un muestreo aleatorio simple y se empleó Stata12 para análisis. Resultados: El 26,38% de encuestados se realizó una radiografía de tórax, principalmente por chequeo general (57,89%); aquellos que no fue predominantemente por falta de interés (60,38%). No se encontró asociación significativa entre las variables estudiadas (RP: 1,3 IC 95%: 0,6-2,9). Conclusión: No existe asociación significativa entre tener familiares profesionales de la salud y realizarse una radiografía preventiva. Más del 70% de casos con ausencia de placa son por falta de interés. / Introduction: Prevention is defined as the reduction of risk factors, detention in the progression of the disease and minimizing its consequences (WHO). In 2006, no association was found between social determinants among medical students in a Peruvian university, and health promotion and prevention. The main of the study is to determine if there is an association in having healthcare professional relatives and getting chest x-ray in the last year, in medical students from a Peruvian university. Materials and method: analytical transversal, in which a data collection form was used, tested in a pilot in order to calculate the sample size. The study population was medical students from a Peruvian University. We performed a simple random sampling and used Stata12 for the analysis. Results: 26,38% students got a chest x-ray, mainly because of general medical examination (57,89%), the ones who did not were mostly because of lack of interest (60,38%). We didn`t found a significant association between the studied variables (PR:1,3 IC95%:0,6-2,9). 31,58% of the interviewed with healthcare professional relatives and the 24,53% without healthcare professional relatives got the test. Conclusions: There is no significant association between having healthcare professional relatives and getting a preventive chest x-ray. More than 70% of the cases that did not get a chest x-ray are due to the lack of interest. / Tesis
8

Espirometria  em pacientes portadores de artrite reumatoide e sua associação com aspectos epidemiológicos, clínicos, radiológicos e tratamento / Spirometry among rheumatoid arthritis patients and its association with epidemiological, clinical, radiographic and treatment aspects

Kawassaki, Alexandre de Melo 03 April 2014 (has links)
INTRODUÇÃO: Artrite reumatoide (AR) é uma doença inflamatória autoimune comum, de predomínio feminino e presente em 1% da população brasileira. O acometimento do sistema respiratório é frequente e ocorre em aproximadamente 50% desta população, principalmente as doenças de vias aéreas e as doenças pulmonares intersticiais. Pacientes tabagistas têm maior chance de desenvolver AR em relação aos não tabagistas, mas o papel do tabaco na doença pulmonar da AR ainda está indefinido. Este trabalho foi dividido em 2 partes. Na primeira avaliamos as características epidemiológicas, clínicas, radiográficas e espirométricas dos pacientes com AR, e comparamos o grupo de pacientes com alterações em qualquer dos exames realizados com grupo onde os exames foram normais. Na segunda parte, fizemos uma avaliação mais aprofundada do sistema respiratório dos pacientes com alteração à espirometria e os comparamos de acordo com a exposição ao tabagismo: elevada (carga tabágica > 10 anos.maço) contra baixa ou ausente. MÉTODOS: Pacientes acompanhados no ambulatório de Artrite Reumatoide do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo foram submetidos a um estudo de corte transversal com avaliação clínica, oximetria de pulso em repouso, radiografia de tórax e espirometria. Aqueles que apresentavam espirometria alterada foram submetidos a tomografia de alta resolução do tórax (TCAR) e função pulmonar com espirometria, pletismografia, difusão de monóxido de carbono (DLCO) e teste de washout de nitrogênio por respiração única. RESULTADOS: Um total de 246 pacientes foram analisados. História de tabagismo prévio ou atual foi visto em metade da amostra. Houve baixa prevalência de nódulos reumatoides e Síndrome de Sjögren. Alterações à espirometria foram vistas em 30% dos pacientes, radiografia de tórax em 45% e oximetria de pulso em 13%. Exames normais estavam simultaneamente presentes em apenas 41% dos casos. Houve fraca correlação negativa entre carga tabágica e diferentes parâmetros da espirometria. No grupo de pacientes com elevada exposição ao tabaco, observamos uma maior frequência de enfisema à TCAR de tórax e menor DLCO, enquanto que no grupo com exposição baixa ou ausente houve maior prevalência de bronquiolite. CONCLUSÕES: Alteração combinada em radiografia de tórax, espirometria e oximetria de pulso foi mais frequentemente observada em pacientes com mais idade, história de tabagismo e uso prévio de metotrexate e biológicos. Apesar de frequentes, a maioria das alterações à radiografia de tórax e espirometria foram leves. A exposição ao tabagismo consegue explicar apenas uma pequena parte das alterações espirométricas da doença pulmonar da AR. A maioria dos pacientes com alteração à espirometria apresentou TCAR de tórax e função pulmonar sugestivas de doença pulmonar obstrutiva, principalmente bronquiolite. A presença de enfisema à TCAR é um marcador altamente específico de exposição ao tabaco / INTRODUCTION: Rheumatoid Arthritis (RA) is a frequent connective tissue disorder, occurring mainly in women, with a 1% prevalence in Brazil. Pulmonary disease, which is present in up to 50% of patients, manifests most commonly as interstitial lung disease (ILD) and airways disease. A high frequency of smoking is observed among RA patients, but its role on pulmonary involvement is unknown. This work was divided in 2 parts. At the first part, we analyzed epidemiological, clinical, radiographic and spirometric RA patients´ characteristics, and compared the group of patients with any abnormality on complementary medical tests against the group with normal tests. At the second part, patients with abnormal spirometry were submitted to a more complex respiratory evaluation, and we compared RA patients with high tobacco exposure ( > 10 pack-years) versus absent or low tobacco exposure. METHODS: RA patients undergoing regular follow-ups at the rheumatoid arthritis clinic of the Rheumatology Division, University of Sao Paulo Medical School, Brazil, were submitted to a cross-sectional clinical pulmonary evaluation, rest pulse oximetry, chest radiograph and spirometry. Those with abnormal spirometry were submitted to chest high-resolution computed tomography (HRCT) and pulmonary function tests with spirometry, plethysmography, carbon monoxide diffusion capacity (DLCO) and single breath nitrogen washout. RESULTS: A total of 246 RA patients underwent complete assessments. Half of the population reported tobacco exposure. Rheumatoid nodules and Sjögren Syndrome were uncommon. Spirometry was abnormal in 30% of the patients; CXR was abnormal in 45%, and pulse oximetry was abnormal in 13%. Normal CXR, spirometry and oximetry were observed simultaneously in only 41% of the RA patients. A weak negative correlation was found between tobacco exposure and spirometric parameters. Thorax HRCT emphysema and lower DLCO were more frequent in patients with high tobacco exposure, while patients with absent or low tobacco exposure had a higher frequency of bronchiolitis. CONCLUSIONS: A significant difference was observed in age, smoking status, and ever methotrexate or biologic treatments when comparing patients with normal and abnormal complementary medical tests. Even though radiographic and spirometric abnormalities were frequent, most of them were mild. Tobacco exposure was slightly responsible for RA patients´ spirometric abnormalities. HRCT and pulmonary function tests compatible with obstructive lung disease, mainly bronchiolitis, were the most frequent patterns among RA patients with abnormal spirometry. HRCT emphysema was a highly specific marker of tobacco exposure
9

Espirometria  em pacientes portadores de artrite reumatoide e sua associação com aspectos epidemiológicos, clínicos, radiológicos e tratamento / Spirometry among rheumatoid arthritis patients and its association with epidemiological, clinical, radiographic and treatment aspects

Alexandre de Melo Kawassaki 03 April 2014 (has links)
INTRODUÇÃO: Artrite reumatoide (AR) é uma doença inflamatória autoimune comum, de predomínio feminino e presente em 1% da população brasileira. O acometimento do sistema respiratório é frequente e ocorre em aproximadamente 50% desta população, principalmente as doenças de vias aéreas e as doenças pulmonares intersticiais. Pacientes tabagistas têm maior chance de desenvolver AR em relação aos não tabagistas, mas o papel do tabaco na doença pulmonar da AR ainda está indefinido. Este trabalho foi dividido em 2 partes. Na primeira avaliamos as características epidemiológicas, clínicas, radiográficas e espirométricas dos pacientes com AR, e comparamos o grupo de pacientes com alterações em qualquer dos exames realizados com grupo onde os exames foram normais. Na segunda parte, fizemos uma avaliação mais aprofundada do sistema respiratório dos pacientes com alteração à espirometria e os comparamos de acordo com a exposição ao tabagismo: elevada (carga tabágica > 10 anos.maço) contra baixa ou ausente. MÉTODOS: Pacientes acompanhados no ambulatório de Artrite Reumatoide do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo foram submetidos a um estudo de corte transversal com avaliação clínica, oximetria de pulso em repouso, radiografia de tórax e espirometria. Aqueles que apresentavam espirometria alterada foram submetidos a tomografia de alta resolução do tórax (TCAR) e função pulmonar com espirometria, pletismografia, difusão de monóxido de carbono (DLCO) e teste de washout de nitrogênio por respiração única. RESULTADOS: Um total de 246 pacientes foram analisados. História de tabagismo prévio ou atual foi visto em metade da amostra. Houve baixa prevalência de nódulos reumatoides e Síndrome de Sjögren. Alterações à espirometria foram vistas em 30% dos pacientes, radiografia de tórax em 45% e oximetria de pulso em 13%. Exames normais estavam simultaneamente presentes em apenas 41% dos casos. Houve fraca correlação negativa entre carga tabágica e diferentes parâmetros da espirometria. No grupo de pacientes com elevada exposição ao tabaco, observamos uma maior frequência de enfisema à TCAR de tórax e menor DLCO, enquanto que no grupo com exposição baixa ou ausente houve maior prevalência de bronquiolite. CONCLUSÕES: Alteração combinada em radiografia de tórax, espirometria e oximetria de pulso foi mais frequentemente observada em pacientes com mais idade, história de tabagismo e uso prévio de metotrexate e biológicos. Apesar de frequentes, a maioria das alterações à radiografia de tórax e espirometria foram leves. A exposição ao tabagismo consegue explicar apenas uma pequena parte das alterações espirométricas da doença pulmonar da AR. A maioria dos pacientes com alteração à espirometria apresentou TCAR de tórax e função pulmonar sugestivas de doença pulmonar obstrutiva, principalmente bronquiolite. A presença de enfisema à TCAR é um marcador altamente específico de exposição ao tabaco / INTRODUCTION: Rheumatoid Arthritis (RA) is a frequent connective tissue disorder, occurring mainly in women, with a 1% prevalence in Brazil. Pulmonary disease, which is present in up to 50% of patients, manifests most commonly as interstitial lung disease (ILD) and airways disease. A high frequency of smoking is observed among RA patients, but its role on pulmonary involvement is unknown. This work was divided in 2 parts. At the first part, we analyzed epidemiological, clinical, radiographic and spirometric RA patients´ characteristics, and compared the group of patients with any abnormality on complementary medical tests against the group with normal tests. At the second part, patients with abnormal spirometry were submitted to a more complex respiratory evaluation, and we compared RA patients with high tobacco exposure ( > 10 pack-years) versus absent or low tobacco exposure. METHODS: RA patients undergoing regular follow-ups at the rheumatoid arthritis clinic of the Rheumatology Division, University of Sao Paulo Medical School, Brazil, were submitted to a cross-sectional clinical pulmonary evaluation, rest pulse oximetry, chest radiograph and spirometry. Those with abnormal spirometry were submitted to chest high-resolution computed tomography (HRCT) and pulmonary function tests with spirometry, plethysmography, carbon monoxide diffusion capacity (DLCO) and single breath nitrogen washout. RESULTS: A total of 246 RA patients underwent complete assessments. Half of the population reported tobacco exposure. Rheumatoid nodules and Sjögren Syndrome were uncommon. Spirometry was abnormal in 30% of the patients; CXR was abnormal in 45%, and pulse oximetry was abnormal in 13%. Normal CXR, spirometry and oximetry were observed simultaneously in only 41% of the RA patients. A weak negative correlation was found between tobacco exposure and spirometric parameters. Thorax HRCT emphysema and lower DLCO were more frequent in patients with high tobacco exposure, while patients with absent or low tobacco exposure had a higher frequency of bronchiolitis. CONCLUSIONS: A significant difference was observed in age, smoking status, and ever methotrexate or biologic treatments when comparing patients with normal and abnormal complementary medical tests. Even though radiographic and spirometric abnormalities were frequent, most of them were mild. Tobacco exposure was slightly responsible for RA patients´ spirometric abnormalities. HRCT and pulmonary function tests compatible with obstructive lung disease, mainly bronchiolitis, were the most frequent patterns among RA patients with abnormal spirometry. HRCT emphysema was a highly specific marker of tobacco exposure
10

Instrumento de investigação clínico-epidemiológica em Cardiologia fundamentado no processamento de linguagem natural / A tool for clinical and epidemiological investigation in cardiology based on natural language processing

Castilla, André Coutinho 13 September 2007 (has links)
O registro eletrônico do paciente (REP) está sendo gradativamente implantado no meio médico hospitalar. Grande parte das informações essenciais do REP está armazenada na forma de texto narrativo livre, dificultando operações de procura, análise e comparação de dados. O processamento de linguagem natural (PLN) refere-se a um conjunto de técnicas computacionais, cujo objetivo é a análise de texto através de conhecimentos léxicos, gramaticais e semânticos. O presente projeto propõe a criação de uma ferramenta computacional de investigação clínicoepidemiológica aplicada a textos narrativos médicos. Como metodologia propomos a utilização do processador de linguagem natural especializado em medicina MEDLEE desenvolvido para textos em Inglês. Para que seu uso seja possível textos médicos em Português são traduzidos ao Inglês automaticamente. A tradução automatizada (TA) é realizada utilizando o aplicativo baseado em regras SYSTRAN especialmente configurado para processar textos médicos através da incorporação de terminologias especializadas. O resultado desta seqüência de TA e PLN são informações conceituais que serão investigadas à procura de achados clínicos pré-definidos, atrvés de inferência lógica sobre uma ontologia. O objetivo experimental desta tese foi conduzir um estudo de recuperação de informações em um conjunto de 12.869 relatórios de radiografias torácicas à procura de vinte e dois achados clínicos e radiológicas. A sensibilidade e especificidade médias obtidas em comparação com referência formada pela opinião de três médicos radiologistas foram de 0,91 e 0,99 respectivamente. Os resultados obtidos indicam a viabilidade da procura de achados clínicos em relatórios de radiografias torácicas através desta metodologia de acoplamento da TA e PLN. Conseqüentemente em trabalhos futuros poderá ser ampliado o número de achados investigados, estendida a metodologia para textos de outras modalidades, bem como de outros idiomas / The Electronic Medical Record (EMR) is gradually replacing paper storage on clinical care settings. Most of essential information contained on EMR is stored as free narrative text, imposing several difficulties on automated data extraction and retrieval. Natural language processing (NLP) refers to computational linguistics tools, whose main objective is text analysis using lexical, grammatical and semantic knowledge. This project describes the creation of a computational tool for clinical and epidemiologic queries on narrative medical texts. The proposed methodology uses the specialized natural language processor MEDLEE developed for English language. To use this processor on Portuguese medical texts chest x-ray reports were Machine Translated into English. The machine translation (MT) was performed by SYSTRAN software, a rule based system customized with a specialized lexicon developed for this project. The result of serial coupling of MT an NLP is tagged text which needs further investigation for extracting clinical findings, whish was done by logical inference upon an ontolgy. The experimental objective of this thesis project was to investigate twenty-two clinical and radiological findings on 12.869 chest x-rays reports. Estimated sensitivity and specificity were 0.91 and 0.99 respectively. The gold standard reference was formed by the opinion of three radiologists. The obtained results indicate the viability of extracting clinical findings from chest x-ray reports using the proposed methodology through coupling MT and NLP. Consequently on future works the number of investigated conditions could be expanded. It is also possible to use this methodology on other medical texts, and on texts of other languages

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