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1
Pascoal, Ana Isabel Lourenco. "Optimisation of image quality and patient dose for chest radiography with digital radiographic systems." Thesis, King's College London (University of London), 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.438195.
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Elhain, Ahmed M. S. B. "An investigation of the influence of radiographic malpositioning and image processing algorithm selection on ICU/CCU chest radiographs." Thesis, University of Bradford, 2013. http://hdl.handle.net/10454/7342.
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Mobile chest radiography remains the most appropriate test for critical care
patients with cardiorespiratory changes and with patients who have chest tubes
and lines as a monitoring tool, and to detect complications related to their use.
However, one of the most frequent issues recognized radiographically with
patients in critical care is chest tubes and lines malposition. This can be related to
technical quality reasons which can affect their appearance in the chest
radiography.
This research considers how the technical quality of the ICU/CCU chest radiography
can impact upon the appearance of chest tubes/lines and how that appearance can
impact on the decision making.
Results show that the methods used in the chest phantom experiment to estimate
the degree of angulation have a large effect upon the appearance of anatomical
structures, but it does not have a particularly large effect upon the apparent
changes of tube/line position central venous catheter and endotracheal tube (CVC,
ETT).
The study also shows that there was a little difference between the two image
processing algorithms, apart from the visualisation of sharp reproduction of the
trachea and proximal bronchi, which was significantly better using the standard
algorithm compared to the inverted algorithm.
The two methods used to estimate the degree of angulation and the apparent
position of the CVC/ETT on 17 mobile chest radiographs provide limited useful
information to the image interpreter in estimating the degree of angulation and
degree of malpositioning of the tube and line.
3
SAKUMA, SADAYUKI, TAKEO ISHIGAKI, KENGO ITO, MITSURU IKEDA, and MITSUHIKO HIROSE. "Considerations for Standard Chest Radiography: the Long Film-Focus Distance Technique." Nagoya University School of Medicine, 1993. http://hdl.handle.net/2237/17529.
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Monshi, Maram Mahmoud A. "Deep Learning in Chest Radiography: From Report Labeling to Image Classification." Thesis, The University of Sydney, 2022. https://hdl.handle.net/2123/29716.
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Chest X-ray (CXR) is the most common examination performed by a radiologist. Through CXR, radiologists must correctly and immediately diagnose a patient’s thorax to avoid the progression of life-threatening diseases. Not only are certified radiologists hard to find but also stress, fatigue, and lack of experience all contribute to the quality of an examination. As a result, providing a technique to aid radiologists in reading CXRs and a tool to help bridge the gap for communities without adequate access to radiological services would yield a huge advantage for patients and patient care. This thesis considers one essential task, CXR image classification, with Deep Learning (DL) technologies from the following three aspects: understanding the intersection of CXR interpretation and DL; extracting multiple image labels from radiology reports to facilitate the training of DL classifiers; and developing CXR classifiers using DL.
First, we explain the core concepts and categorize the existing data and literature for researchers entering this field for ease of reference. Using CXRs and DL for medical image diagnosis is a relatively recent field of study because large, publicly available CXR datasets have not been around for very long. Second, we contribute to labeling large datasets with multi-label image annotations extracted from CXR reports. We describe the development of a DL-based report labeler named CXRlabeler, focusing on inductive sequential transfer learning. Lastly, we explain the design of three novel Convolutional Neural Network (CNN) classifiers, i.e., MultiViewModel, Xclassifier, and CovidXrayNet, for binary image classification, multi-label image classification, and multi-class image classification, respectively. This dissertation showcases significant progress in the field of automated CXR interpretation using DL; all source code used is publicly available. It provides methods and insights that can be applied to other medical image interpretation tasks.
5
Al-Kabir, Zul Waker Mohammad. "A knowledge based system for diagnosis of lung diseases from chest x-ray images /." Canberra : University of Canberra, 2007. http://erl.canberra.edu.au/public/adt-AUC20070823.160921/index.html.
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Thesis (PhD) -- University of Canberra, 2006.Thesis submitted in fulfilment of the requirements for the degree of Master of Information Science in the School of Information Sciences and Engineering under the Division of Business, Law and Sciences at the University of Canberra, May 2006. Bibliography: leaves 120-132.
6
Piqueras, Pardellans Joaquim. "Assessment of a micro-grid Ionization-chamber (EOS) for low-dose chest radiography." Doctoral thesis, Universitat Autònoma de Barcelona, 2016. http://hdl.handle.net/10803/378369.
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EOS és una nova tecnologia d'imatge que fa servir un detector de radiació gasós, una cambra d'ionització de micro-reixeta, derivada del Micromegas desenvolupat per Georges Charpak (Premi Nobel 1992) per recerca en física d'altes energies al CERN (Ginebra, CH). Aquests detectors poden obtenir imatges mèdiques a baixa dosi, permetent col·limacions estrictes que eviten la radiació difusa que degrada dosi i qualitat. El prototip EOS, fent servir feixos de raigs-X molt fins (500 µm), va ser pensat per fer radiografia a baixa dosi de l'esquelet en bipedestació. Dissenyat amb dos tubs de raigs-X i dos detectors, realitza una adquisició per escanejat lineal biplanar sincrònica, de dues imatges (a 90º) del cos. Aquest mètode biplanar permet l'extracció automàtica de punts de referència anatòmics que poden ser matemàticament projectats com un model 3D de l'esquelet real del pacient. El programari EOS pot generar models 3D amb baixa dosi, entre 1/10 i 1/100, de les modalitats existents (radiografia computada (CR), radiografia digital (DR), o TC a baixa-dosi). L'objectiu principal de la recerca d'aquest prototip, la imatge de columna, va ser validat, i el seu subseqüent re-disseny industrial ha acabat com un dispositiu mèdic certificat per a estudis de l'esquelet: EOS ('EOS Imaging, Paris, France)'.
Preparant la fase experimental de EOS en columna, un segon objectiu va ser considerat: valorar l'aplicabilitat del prototip EOS a l'exploració radiogràfica més freqüent: radiografia de tòrax. Si EOS fos validat, permetria aplicar-lo a un altre camp del radiodiagnòstic. La radiografia del tòrax és una prova que pot comportar algunes dificultats en un dispositiu voluminós, d'escanejat lineal, biplanar, amb baixa dosi i baixa resolució espacial, com són els detectors de micro-reixeta, a investigar.
Material i mètodes: Es va preparar un estudi prospectiu comparant exploracions repetides entre EOS i un equip radiogràfic estat-de-l'art (DR, detector pla de aSi-Csi), per valorar l'aplicabilitat clínica, problemes tècnics, dosi i qualitat d'imatge. Un grup de 40 adults, amb radiografia de tòrax programada al Hôpital Univ. Erasme (Brussel·les, BE), van ser enrolats per a fer un estudi repetit amb EOS (amb 50% dosi de CR). Les imatges recollides van ser puntuades independentment per quatre radiòlegs seguint els 'European quality criteria in diagnostic imaging', incorporant reptes com valorar estructures anatòmiques fines. Es recolliren dades tècniques, estudis dosimètrics addicionals, comparatius amb CR, i mesura de dades de dosi i de rendiment del detector.
Resultats: 37 dels 40 casos van ser analitzats. La radiografia va ser correcta amb EOS, amb 13,5% d'estudis repetits. La dosi de radiació es superior amb EOS (0.22 mGy) que amb DR (0.05) però menys que la DRL o dosi per CR. Artefactes de soroll i 'arrissat' redueixen la FTM (funció de transferència de la modulació) mesurada a 1-1.5 pl/mm. La puntuació en qualitat d'imatge entre EOS i DR va ser comparable, amb millor puntuació per a EOS en via aèria, mediastí o en cobertura anatòmica.
Conclusió: EOS és una modalitat funcional que compleix les dosis de referència. La dosi és més alta que per DR i més baixa que per CR, per supressió de la radiació difusa. En qualitat d'imatge, EOS no mostra valoracions inferiors significants a la DR, fins i tot en estructures fines; pot atribuir-se a la resolució més gran de densitats i a l'absència de difusa que compensen la seva inferior resolució espacial. Caldrà fer desenvolupaments addicionals per millorar el control de la dosi i per millorar resolució, i caldrà fer recerca dirigida a validar resultats en sèries amb patologies clíniques.The EOS is a new 2D/3D radio-imaging technology that uses a gaseous radiation detector and micro-grid ionization chamber derived from Micromegas, the micro-grid developed by the Nobel Prize winner Georges Charpak and extensively used in high-energy research (eg, CERN, Geneva, Switzerland). The detectors are very efficient and enable low-dose medical imaging by stringent collimation, which avoids the undesired scattered radiation that increases dose and degrades image quality. The EOS prototype uses very thin (500 µm) fan-like x-ray beams and was planned for low-dose standing radiography of the human skeleton. It has two x-ray tubes and two detectors that allow synchronous biplanar linear acquisition of two 90-degree images of the body. The biplanar method was designed for automatic extraction of anatomic reference points that can be mathematically projected as a 3D model of a patient's skeleton. EOS software can build 3D models using lower radiation doses (1/10 to 1/100) than existing systems (computed radiography [CR], digital radiography [DR], or low-dose CT). The main application of the prototype, spine imaging, has been validated, and the subsequent, re-designed industrial EOS (EOS Imaging, Paris, France) has attained certification for skeletal studies. While preparing the experimental phase of EOS for spine imaging, a second objective was considered: to assess applicability of the EOS prototype to another field of imaging, the chest x-ray, the most common radiologic exam. Chest x-rays could pose several difficulties for a large, linear-scanning, biplanar, low-dose and low-spatial-resolution technique, in this case micro-grid detectors, which would have to be investigated. Material and methods: A prospective study was designed to assess the clinical feasibility, technical problems, dose and image quality of EOS as compared to a state-of-the-art DR system, the aSi-CsI flat panel detector. Forty adult patients undergoing scheduled chest x-ray examinations at the Erasme University Hospital (Brussels, BE) were recruited for paired examinations using EOS (at 50% dose) and DR. Paired data and images were compiled. Image data sets were independently scored by 4 radiologists according to the European Quality Criteria in Diagnostic Imaging, with additional challenges, such as scoring of thin anatomical structures. The dosimetry data obtained were also compared to those of CR, and experimental laboratory data were compiled on collimation and detector performance. Results: 37 of 40 cases were available for complete analysis. EOS chest examinations were acquired with a 13,5% repeat rate. Radiation dose (PA) was higher for EOS (0.22 mGy) than with DX (0.05), but less than CR or reference doses (0.3 mGy). Noise and ripple artifacts lowered the MTF (Modulation Transfer Function) to 1-1.5 pl/mm. Image quality scores between EOS and DX were comparable, but with better scores for EOS in several items as air-ways, mediastinum or anatomic coverage. Conclusion: EOS is feasible for chest imaging and is compliant with the chest reference doses. Radiation dose was higher than with DR, but lower than with CR, achieved by suppressing scatter. EOS image quality scores were not significantly inferior from those of DR, even for thin structures, as the extended density resolution and absence of scatter of EOS compensated for the inferior spatial resolution. Further development is needed to reach better dose containment and improve resolution, with validation in patients having various clinical conditions.
7
Kong, Xiang. "Optimization of image quality and minimization of radiation dose for chest computed radiography." Oklahoma City : [s.n.], 2006.
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8
Zhang, Hui, and 張暉. "Temporal subtraction of chest radiograph using graph cuts and free-form deformations." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2007. http://hub.hku.hk/bib/B40203451.
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Rehm, Kelly. "Development and image quality assessment of a contrast-enhancement algorithm for display of digital chest radiographs." Diss., The University of Arizona, 1992. http://hdl.handle.net/10150/185844.
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This dissertation presents a contrast-enhancement algorithm called Artifact-Suppressed Adaptive Histogram Equalization (ASAHE). This algorithm was developed as part of a larger effort to replace the film radiographs currently used in radiology departments with digital images. Among the expected benefits of digital radiology are improved image management and greater diagnostic accuracy. Film radiographs record X-ray transmission data at high spatial resolution, and a wide dynamic range of signal. Current digital radiography systems record an image at reduced spatial resolution and with coarse sampling of the available dynamic range. These reductions have a negative impact on diagnostic accuracy. The contrast-enhancement algorithm presented in this dissertation is designed to boost diagnostic accuracy of radiologists using digital images. The ASAHE algorithm is an extension of an earlier technique called Adaptive Histogram Equalization (AHE). The AHE algorithm is unsuitable for chest radiographs because it over-enhances noise, and introduces boundary artifacts. The modifications incorporated in ASAHE suppress the artifacts and allow processing of chest radiographs. This dissertation describes the psychophysical methods used to evaluate the effects of processing algorithms on human observer performance. An experiment conducted with anthropomorphic phantoms and simulated nodules showed the ASAHE algorithm to be superior for human detection of nodules when compared to a computed radiography system's algorithm that is in current use. An experiment conducted using clinical images demonstrating pneumothoraces (partial lung collapse) indicated no difference in human observer accuracy when ASAHE images were compared to computed radiography images, but greater ease of diagnosis when ASAHE images were used. These results provide evidence to suggest that Artifact-Suppressed Adaptive Histogram Equalization can be effective in increasing diagnostic accuracy and efficiency.
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ISHIGAKI, TAKEO, MITSUHIKO HIROSE, KIYOKO NAKAMURA, MITSURU IKEDA, KENGO ITO, and NICOLAS MILLA. "FUNDAMENTAL AND CLINICAL EVALUATION OF CHEST COMPUTED TOMOGRAPHY IMAGING IN DETECTABILITY OF PULMONARY NODULE." Nagoya University School of Medicine, 1994. http://hdl.handle.net/2237/16074.
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McLean, Ian Donald. "Optimisation of mediastinal and lung contrast on chest radiographs using a novel twin screen-film cassette." Thesis, Queensland University of Technology, 1995.
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12
Moore, Craig Steven. "Optimisation of computed radiography chest imaging utilising a novel simulation technique derived from real patient computed tomography data sets." Thesis, University of Hull, 2011. http://hydra.hull.ac.uk/resources/hull:5762.
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To optimise any medical digital imaging system for chest radiography, it is vital that the images used for optimisation contain projected anatomy, or in other words, anatomical noise. In this thesis, a method to produce and validate a digitally reconstructed radiograph (DRR) computer algorithm that utilises real patient computed tomography (CT) data sets is presented. The algorithm uses a ray casting DRR calculation method to project X-ray pencil beams through CT data and derive the photon energy absorbed in a virtual computed radiography (CR) phosphor. Radiation scatter and CR system noise are added post DRR calculation. Quantitative and qualitative validation has shown the algorithm simulates chest CR images of average and obese patients with realistic anatomical and system noise. This has allowed images to be generated using various X-ray exposure parameters, i.e. tube potential, scatter rejection and receptor dose, which can then be used in the optimisation exercise. However, the algorithm is not without limitations; the impact of these on the resulting images is discussed. Simulated images reconstructed at the various X-ray exposure parameters and techniques were scored by experienced image evaluators; optimum tube potential, scatter rejection technique and receptor doses for clinical CR chest radiography have been derived. At the outset of this work, CR chest exposure factors across the Hull & East Yorkshire Hospitals NHS Trust (HEY) were not standardised, and therefore not optimised; this thesis concludes with recommendations to the HEY Radiology Department for optimum exposure factors and technique for chest radiography. These were implemented across the Trust as a result of this work. In summary, a DRR computer algorithm has been produced (and validated) that adequately simulates anatomical and system noise; image evaluators are able to grade simulated chest images presented at different X-ray exposure parameters in order to optimise radiographic technique for clinical CR chest radiography, without the need for repeat patient exposures.
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Woznitza, Nick. "The diagnostic accuracy of reporting radiographer chest X-ray interpretations and their influence on clinicians' diagnostic decision-making : a comparison with consultant radiologists." Thesis, Canterbury Christ Church University, 2016. http://create.canterbury.ac.uk/15847/.
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Background: Diagnostic imaging plays an expanding and central role in patients' medical care. Radiographer clinical reporting is being increasingly used in patient focused services. There is a paucity of research that has examined radiographer chest X-ray reporting. Aim: To determine the diagnostic accuracy of reporting radiographer chest X-ray (CXR) reporting and the influence that CXR reports have on clinicians' diagnostic decision-making. Method: A quasi-experimental study determined the diagnostic accuracy of a cohort of reporting radiographers in CXR interpretation, using a free-response methodology. The influence of CXR reports on clinicians' diagnostic decision-making was determined with a cohort study. A non-inferiority approach was used, in line with Royal College of Radiologists and College of Radiographers guidance that reporting radiographers must be comparable to consultant radiologists. Results: The diagnostic accuracy of reporting radiographers (RR) was non-inferior to consultant radiologists (CR) for all measures, all p < 0.0001; unweighted JAFROC (RR Figure of Merit [FoM]=0.828, 95%CI 0.808-0.847; CR FoM=0.788, 95%CI 0.766-0.811), weighted JAFROC (RR FoM=0.830, 95%CI 0.811-0.849; CR FoM=0.786, 95%CI 0.764-0.808) and inferred ROC (RR Area Under the Curve [AUC]=0.909, 95%CI 0.887-0.931; CR AUC=0.903, 95%CI 0.882-0.924). No difference was found in the number of CXR reports that produced a correct most likely and/or most serious diagnosis (RR 876 of 1337 cases; CR 810 of 1368; p=0.103). Uncorrected most likely diagnostic confidence (RR 72.5 to 80.2; CR 71.0 to 80.4) and uncorrected most serious diagnostic confidence (RR 34.0 to 41.9; CR 33.5 to 39.2) of reporting radiographer CXR reports was non-inferior to consultant radiologists (p < 0.001). Corrected most likely diagnostic confidence, calculated using the Tsushima methodology, was lower (RR 4.61; CR 5.02) with no apparent difference, but noninferiority was not confirmed (p > 0.05). Conclusion: With appropriate postgraduate education, reporting radiographers are able to interpret chest X-rays at a level comparable to consultant radiologists.
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Zhou, Bo. "DETECTION AND QUANTIFICATION OF CORONARY CALCIUM FROMDUAL ENERGY CHEST X-RAYS: PHANTOM FEASIBILITY STUDY." Case Western Reserve University School of Graduate Studies / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=case1481216785398625.
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Alves, Allan Felipe Fattori [UNESP]. "Construção de fantomas homogêneos pediátricos de crãnio e tórax para otimização de imagens em radiografia computadorizada." Universidade Estadual Paulista (UNESP), 2014. http://hdl.handle.net/11449/123924.
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Este trabalho teve como objetivo a otimização de imagens de radiografia computadorizada (CR, do inglês, computed radiography) de crânio e tórax de pacientes pediátricos entre 1 e 5 anos de idade. Para atingir esse objetivo foram desenvolvidos fantomas homogêneos pediátricos, que simularam a faixa etária em estudo, a partir de exames retrospectivos de tomografia computadorizada (CT, do inglês, computed tomography). Nesse procedimento foi utilizado um algoritmo computacional para quantificar as espessuras médias de tecidos biológicos (tecido pulmonar, adiposo, mole e ósseo) presentes nas regiões anatômicas em estudo. Essas espessuras foram convertidas em materiais simuladores (lucite e alumínio) de modo a compor os fantomas homogêneos de crânio e tórax. As incertezas relativas no processo de quantificação dos exames de crânio foram de 3,5% para tecido mole e 9,5% para tecido ósseo. Na quantificação dos exames de tórax a incerteza relativa foi de 19,4% para o tecido pulmonar, 13,0% para o tecido mole e 20,0% para o tecido ósseo. O fantoma de tórax foi construído com 7,3 cm de lucite distribuídos em 4 placas de mesma espessura (15,0 x 15,0 x 1,82) cm³ arranjadas em dois pares, separadas por um espaçamento de ar de 2,86 cm. Duas placas de alumínio de (15,0 x 15,0 x 0,13) cm³ e (150,0 x 150,0 x 1,0) mm³ foram inseridas, respetivamente, entre os pares superior e inferior de lucite. O fantoma de crânio foi construído com 11,98 cm de lucite distribuídos em cinco placas de mesma espessura (15,0 x 15,0 x 2,33) cm³. Duas placas de alumínio (15,0 x 15,0 x 0,16) cm³ e (15,0 x 15,0 x 0,12) cm³ foram inseridas, respectivamente, entre os pares superior e inferior de lucite. Os fantomas homogêneos foram utilizados no processo de otimização de imagens em sistemas CR, para calibração do feixe de raios X. No processo de calibração foram determinadas técnicas-teste (combinação kVp e mAs), que produziram índices de ...
The aim of this work was to optimize computed radiography techniques of skull and chest for pediatric patients between 1 and 5 years old. To achieve this goal, pediatric homogenous phantoms were developed from retrospective computed tomography (CT) scans. In this procedure, a computational algorithm was used to quantify the average thickness of biological tissue (lung, fat, soft and bone tissue) present on the anatomic region under study. These thicknesses were converted into simulators materials (Lucite and aluminum) to build the homogeneous phantoms of skull and chest. The relative uncertainties in the quantification process of skull examinations were 3.5% for soft tissue and 9.5% for bone tissue. In the chest examination, the relative uncertainties were 19.4% for lung tissue, 13.0% for soft tissue and 20.0% for bone tissue. The chest phantom was constructed with 7.3 cm of lucite distributed in four plates of the same thickness (15.0 x 15.0 x 1.82) cm³ arranged in two pairs, separated by a spacing of 2.86 cm of air. Two aluminum plates (15.0 x 15.0 x 0.13) cm³ and (15.0 x 15.0 x 0.10) mm³ were inserted, respectively, between the upper and lower pairs of Lucite. The skull phantom was constructed with 11.98 cm of Lucite distributed in five plates of the same thickness (15.0 x 15.0 x 2.33) cm³. Two aluminum plates (15.0 x 15.0 x 0.16) cm³ and (15.0 x 15.0 x 0.12) cm³ were inserted between the upper and lower pairs of Lucite. These homogeneous phantoms were used in the optimization process for CR systems to determine test techniques (kVp and mAs combination), which produced levels of exposure around 1.96 lgM. The test images, obtained in this process, were used in the determination of physical parameters such as the effective detective quantum efficiency (eDQE) and contrast-detail. These parameters were associated with the optimal images of skull and chest for adult patients obtained in previous studies. Optimal images obtained in ...
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Alves, Allan Felipe Fattori. "Construção de fantomas homogêneos pediátricos de crãnio e tórax para otimização de imagens em radiografia computadorizada /." Botucatu, 2014. http://hdl.handle.net/11449/123924.
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Orientador: José Ricardo de Arruda MirandaCoorientador: Diana rodrigues de Pina
Banca: Sérgio Barbosa Duarte
Banca: Rozemeire Garcia Marques
Resumo: Este trabalho teve como objetivo a otimização de imagens de radiografia computadorizada (CR, do inglês, computed radiography) de crânio e tórax de pacientes pediátricos entre 1 e 5 anos de idade. Para atingir esse objetivo foram desenvolvidos fantomas homogêneos pediátricos, que simularam a faixa etária em estudo, a partir de exames retrospectivos de tomografia computadorizada (CT, do inglês, computed tomography). Nesse procedimento foi utilizado um algoritmo computacional para quantificar as espessuras médias de tecidos biológicos (tecido pulmonar, adiposo, mole e ósseo) presentes nas regiões anatômicas em estudo. Essas espessuras foram convertidas em materiais simuladores (lucite e alumínio) de modo a compor os fantomas homogêneos de crânio e tórax. As incertezas relativas no processo de quantificação dos exames de crânio foram de 3,5% para tecido mole e 9,5% para tecido ósseo. Na quantificação dos exames de tórax a incerteza relativa foi de 19,4% para o tecido pulmonar, 13,0% para o tecido mole e 20,0% para o tecido ósseo. O fantoma de tórax foi construído com 7,3 cm de lucite distribuídos em 4 placas de mesma espessura (15,0 x 15,0 x 1,82) cm³ arranjadas em dois pares, separadas por um espaçamento de ar de 2,86 cm. Duas placas de alumínio de (15,0 x 15,0 x 0,13) cm³ e (150,0 x 150,0 x 1,0) mm³ foram inseridas, respetivamente, entre os pares superior e inferior de lucite. O fantoma de crânio foi construído com 11,98 cm de lucite distribuídos em cinco placas de mesma espessura (15,0 x 15,0 x 2,33) cm³. Duas placas de alumínio (15,0 x 15,0 x 0,16) cm³ e (15,0 x 15,0 x 0,12) cm³ foram inseridas, respectivamente, entre os pares superior e inferior de lucite. Os fantomas homogêneos foram utilizados no processo de otimização de imagens em sistemas CR, para calibração do feixe de raios X. No processo de calibração foram determinadas técnicas-teste (combinação kVp e mAs), que produziram índices de ...
Abstract: The aim of this work was to optimize computed radiography techniques of skull and chest for pediatric patients between 1 and 5 years old. To achieve this goal, pediatric homogenous phantoms were developed from retrospective computed tomography (CT) scans. In this procedure, a computational algorithm was used to quantify the average thickness of biological tissue (lung, fat, soft and bone tissue) present on the anatomic region under study. These thicknesses were converted into simulators materials (Lucite and aluminum) to build the homogeneous phantoms of skull and chest. The relative uncertainties in the quantification process of skull examinations were 3.5% for soft tissue and 9.5% for bone tissue. In the chest examination, the relative uncertainties were 19.4% for lung tissue, 13.0% for soft tissue and 20.0% for bone tissue. The chest phantom was constructed with 7.3 cm of lucite distributed in four plates of the same thickness (15.0 x 15.0 x 1.82) cm³ arranged in two pairs, separated by a spacing of 2.86 cm of air. Two aluminum plates (15.0 x 15.0 x 0.13) cm³ and (15.0 x 15.0 x 0.10) mm³ were inserted, respectively, between the upper and lower pairs of Lucite. The skull phantom was constructed with 11.98 cm of Lucite distributed in five plates of the same thickness (15.0 x 15.0 x 2.33) cm³. Two aluminum plates (15.0 x 15.0 x 0.16) cm³ and (15.0 x 15.0 x 0.12) cm³ were inserted between the upper and lower pairs of Lucite. These homogeneous phantoms were used in the optimization process for CR systems to determine test techniques (kVp and mAs combination), which produced levels of exposure around 1.96 lgM. The test images, obtained in this process, were used in the determination of physical parameters such as the effective detective quantum efficiency (eDQE) and contrast-detail. These parameters were associated with the optimal images of skull and chest for adult patients obtained in previous studies. Optimal images obtained in ...
Mestre
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Campos, Leandro Cruz. "Características dos pacientes com tuberculose pulmonar com baciloscopia negativa em uma região com alta prevalência de tuberculose e HIV." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2016. http://hdl.handle.net/10183/148202.
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Introdução: A TB pulmonar com baciloscopia negativa (TPBN) representa 30-60% de todos os casos de TB. A mortalidade destes pacientes pode atingir 25% em populações com alta prevalência de infecção por HIV, e 10-20% da transmissão da TB, em níveis populacionais são atribuídos a casos de TPBN. Métodos: Um estudo retrospectivo foi desenvolvido para avaliar as características epidemiológicas, clínicas e radiológicas de pacientes com TPBN e comparar com pacientes diagnosticados como tendo TB pulmonar com baciloscopia positiva (TPBP). Todos os pacientes adultos (≥ 18 anos) com cultura positiva para Mycobacterium tuberculosis, e diagnóstico de TB pulmonar foram incluídos no estudo. Resultados: 198 pacientes preencheram os critérios do estudo (cultura positiva para Mycobacterium tuberculosis) e foram incluídos na análise. Destes, 69 (34,8%) tiveram cultura positiva (TPBP) e 129 (65,2%) cultura negativa (TPBN). Numa análise univariada, tosse, dispneia e hemoptise foram menos frequentes nos pacientes com baciloscopia negativa, em comparação com os com TPBP. Num modelo multivariável, não ter tosse e não ter padrão radiológico típico de TB foram características independentemente associadas com o diagnóstico de TPBN. Conclusões: Encontramos uma prevalência muito alta de TPBN entre pacientes com TB, num local com alta prevalência de TB e HIV. A ausência de tosse na presença de outros sintomas sugestivos de TB, e não ter padrão radiológico típico de TB foram preditores independentes para TPBN.Introduction: Smear-negative pulmonary TB (SNPT) represents 30-60% of all pulmonary TB cases. The mortality of these patients can reach 25% in populations with high prevalence of HIV infection, and 10-20% of TB transmission at the population level are attributable to SNPT cases. Methods: We conducted a retrospective study to evaluate epidemiological, clinical, and radiological characteristics of patients with SNPT and to compare these with patients who were diagnosed as having smear-positive pulmonary TB (SPPT). All adult patients (≥ 18 years old) with a positive culture for Mycobacterium tuberculosis, and a diagnosis of pulmonary TB were included in the study. Results: 198 patients met the inclusion criteria (positive culture for Mycobacterium tuberculosis) and were included in the analysis. Of these patients, 69 (34,8%) were smear positive (SPPT) and 129 (65,2%) were smear negative (SNPT). In univariate analysis, cough, dyspnea, and hemoptysis were less frequent in SNPT patients in comparison with SPPT patients. In a multivariate model, having no cough and no radiographic pattern typical of TB were the characteristics independently associated with a diagnosis of SNPT. Conclusions: We found a very high prevalence of SNPT among patients with TB in a setting with high TB and HIV prevalence. The absence of cough in the presence of other symptoms suggestive of TB, and having no radiographic pattern typical of TB where independent predictors of SNPT.
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Sprague, Matthew J. "A Genetic Algorithm Approach to Feature Selection for Computer Aided Detection of Lung Nodules." University of Dayton / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1480465837455442.
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Lester, Sonia. "A study of scattered radiation in diagnostic radiology using Monte Carlo simulation." Thesis, Institute of Cancer Research (University Of London), 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287993.
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Silva, Thelma Regina Cintra da. "Análise crítica comparativa, radiográfica e tomográfica, das alterações do trato respiratório de felinos domésticos portadores ou não de imunodeficiência viral." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/10/10137/tde-21102013-181128/.
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Na rotina de felinos domésticos, algumas modalidades de diagnóstico por imagem, como a radiografia simples e, na última década, a tomografia computadorizada (TC) já são amplamente utilizadas. Este estudo teve por objetivo realizar uma análise crítica da contribuição dos exames radiográfico e tomográfico (simples e contrastado), na avaliação do trato respiratório de felinos portadores ou não de imunodeficiência viral (FIV). Identificando as principais alterações encontradas em felinos FIV+ aos exames radiográfico e tomográfico do crânio e tórax. E ainda, correlacionando os achados radiográficos e tomográficos com os resultados laboratoriais de sorologia para imunodeficiência viral felina, citologia e cultura (bacteriana e fúngica) do lavado traqueal. Foram utilizados 20 felinos adultos jovens de ambos os sexos, sendo 14 FIV+ e 06 FIV-, todos provenientes do mesmo gatil. Pela análise estatística houve um maior percentual de felinos FIV+ com opacificação nas bulas timpânicas pela TC (57,14%) e resultado positivo na análise citológica do lavado traqueal (85,71%). Constatou-se que os felinos portadores de imunodeficiência viral possuíram, por meio da avaliação radiográfica e tomográfica, um maior comprometimento do trato respiratório relacionado às cavidades nasais, bulas timpânicas, parênquima pulmonar e vias aéreas inferiores, quando comparados aos felinos negativos para imunodeficiência viral.In internal medicine of domestic cats, imaging modalities, such as radiography and, in the last decade, computed tomography (CT) are widely used. The aim of this study was to perform a critical analysis of the radiographic and tomographic contribution in assessing the respiratory tract of feline immunodeficiency vírus (FIV) infected cats and FIV negative cats. Identifying the radiographic and tomographic findings, in FIV+ cats, of the skull and chest examination. And, correlating radiographic and tomographic findings with the laboratory serology for feine immunodeficiency vírus results, cytology evaluation and culture (bacterial and fungal) from tracheal lavage fluid.Twenty young adults cats of both gender were used, 14 FIV+ and 06 FIV-, all from the same cattery. By the statstical analysis there was a higher percentage of FIV+ infected cats with timpanic bullae opacification by the CT examination (57,14%) and positive cytologic evaluation of traqueal aspirates (85,71%). It was found that FIV+ infected cats has greater involvement of the respiratory tract related to the nasal cavity, tympanic bullae, lung parenchyma and lower airways, when compared with FIV- cats.
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De, Marco Fabio Domenico [Verfasser], Franz [Akademischer Betreuer] Pfeiffer, Pierre [Gutachter] Thibault, and Franz [Gutachter] Pfeiffer. "Image reconstruction, pre-clinical studies, and signal formation investigations at a dark-field chest radiography setup / Fabio Domenico De Marco ; Gutachter: Pierre Thibault, Franz Pfeiffer ; Betreuer: Franz Pfeiffer." München : Universitätsbibliothek der TU München, 2021. http://d-nb.info/1240832753/34.
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Freund, Torsten. "Methodische und klinische Evaluation eines modernen Flachbettdetektors und des Dual-Energy-Verfahrens." Doctoral thesis, [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=980108403.
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Ullman, Gustaf. "Quantifying image quality in diagnostic radiology using simulation of the imaging system and model observers." Doctoral thesis, Linköping : Department of Medicine and Health, Linköping University, 2008. http://www.bibl.liu.se/liupubl/disp/disp2008/med1050s.pdf.
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Butler, Anthony Philip Howard. "Eigenimage Processing of Frontal Chest Radiographs." Thesis, University of Canterbury. Electrical and Computer Engineering, 2007. http://hdl.handle.net/10092/2780.
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The goal of this research was to improve the speed and accuracy of reporting by clinical radiologists. By applying a technique known as eigenimage processing to chest radiographs, abnormal findings were enhanced and a classification scheme developed. Results confirm that the method is feasible for clinical use. Eigenimage processing is a popular face recognition routine that has only recently been applied to medical images, but it has not previously been applied to full size radiographs. Chest radiographs were chosen for this research because they are clinically important and are challenging to process due to their large data content. It is hoped that the success with these images will enable future work on other medical images such as those from CT and MRI. Eigenimage processing is based on a multivariate statistical method which identifies patterns of variance within a training set of images. Specifically it involves the application of a statistical technique called principal components analysis to a training set. For this research, the training set was a collection of 77 normal radiographs. This processing produced a set of basis images, known as eigenimages, that best describe the variance within the training set of normal images. For chest radiographs the basis images may also be referred to as 'eigenchests'. Images to be tested were described in terms of eigenimages. This identified patterns of variance likely to be normal. A new image, referred to as the remainder image, was derived by removing patterns of normal variance, thus making abnormal patterns of variance more conspicuous. The remainder image could either be presented to clinicians or used as part of a computer aided diagnosis system. For the image sets used, the discriminatory power of a classification scheme approached 90%. While the processing of the training set required significant computation time, each test image to be classified or enhanced required only a few seconds to process. Thus the system could be integrated into a clinical radiology department.
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Plessis, Brigitte. "Context-dependent enhancements for digitized chest radiographs." Thesis, University of Ottawa (Canada), 1989. http://hdl.handle.net/10393/5912.
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Stollar, Fabíola. "Correlação clínica, funcional e radiológica em pacientes com fibrose cística." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/5/5141/tde-27102011-150058/.
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Introdução: a variabilidade clínica da fibrose cística (FC) levou ao desenvolvimento de diferentes sistemas de escores de avaliação de sua gravidade. Como nem sempre é possível fazer a monitorizarão do paciente com exames radiológicos, tomográficos, funcionais e clínicos simultaneamente, o entendimento das correlações entre esses métodos é um ponto importante para que a equipe multiprofissional dos centros de FC selecione o método mais adequado na sua rotina de atendimento. Objetivo: avaliar a gravidade das alterações clínicas, estruturais e funcionais de uma população de pacientes com fibrose cística por meio de escores clínicos, radiológicos, tomográficos e testes funcionais e analisar as correlações, por pareamento entre os escores de Shwachman-Kulczychi (E-SK), Brasfield (E. Brasfield), Bhalla (E. Bhalla), espirometria e teste de caminhada de seis minutos (TC6M). Métodos: Estudo transversal prospectivo em pacientes com idade entre 3-21 anos. Foram realizados no mesmo dia: espirometria, TC6M, radiografia de tórax (RX), tomografia computadorizada (TC) de tórax e avaliação do estadio clínico. Utilizou-se a regressão linear (coeficiente de correlação de Spearman) para a análise das correlações entre os exames. Foi construída uma Curva ROC para avaliar o melhor ponto de corte para o valor de escore de Brasfield que indicaria a presença de bronquiectasias na TC. Resultados: 43 pacientes foram avaliados, 19F/24M, 10,5 ± 4,7 anos, com mediana de E. Bhalla, E. Brasfield e E-SK de 10, 17 e 70, respectivamente. Os valores médios (% previsto) de capacidade vital forçada (CVF), volume expiratório forçado no primeiro segundo (VEF1) e fluxo expiratório forçado entre 25 e 75 % da capacidade vital (FEF25-75%) foram, respectivamente, 70,4 ± 26, 59,2 ± 26, 47,4 ± 35,8. Houve correlações significativas entre quase todos os parâmetros estudados. Apenas não houve correlação estatisticamente significativa entre escore do teste de caminhada de seis minutos (Z-TC6M) e aprisionamento + mosaico (r = -0,35), VEF1 70% e E-SK (r = -0,04); VEF1 70% e E. Bhalla (r = -0,32), VEF1 70% e E. Brasfield (r = 0,14), VEF1 70% e Z-TC6M (r =0,14). Através da Curva ROC foi determinado o ponto de corte do escore de Brasfield de 18 como o de melhor sensibilidade (83%), especificidade (92%), valor preditivo positivo (96%) e valor preditivo negativo (71%) para detecção de bronquiectasias na TC de tórax. Conclusões: Nesta casuística de pacientes com fibrose cística houve uma ampla variação quanto à gravidade da doença quando avaliada por parâmetros clínicos, radiológicos, tomográficos e funcionais. Apesar desta variação, houve correlação significativa entre a maioria dos métodos utilizados no estudo. As correlações não foram significativas nos pacientes com função pulmonar normal ou com distúrbio ventilatório obstrutivo leve, o que pode estar relacionado a uma menor capacidade discriminatória entre os diferentes métodos quando o acometimento pulmonar é de grau leve. Nessa amostra estudada, pacientes com escore de Brasfield menor ou igual a 18, tiveram uma probabilidade de 83% de apresentar bronquiectasias na TC de tórax. O teste da caminhada de seis minutos se mostrou como um método complementar alternativo que pode ser utilizado na avaliação da gravidade dos pacientes com FCIntroduction: The clinical variability of cystic fibrosis (CF) led to the development of different scoring systems to evaluate its severity. As it is not always possible to simultaneously assess CF patient with radiography, tomography, functional tests and clinical status, understanding the correlations between these methods is important for the multidisciplinary team of CF centers to select the most suitable method in their routine attendance. Objective: To assess the severity of the clinical, structural and functional characteristics of a population of CF patients by means of clinical scores, chest radiography (CXR), chest tomography (CT) and pulmonary functional tests and to analyze the correlations between Shwachman-Kulczychi score (SK), Brasfield score (Brasfield), Bhalla score (Bhalla), spirometry and six minute walk test (6-MWT). Method: A cross-sectional and prospective study including patients aged 3-21 years-old. Spirometry, 6-MWT, CRX, CT and evaluation of clinical status were performed on the same day. Linear regression (Spearman correlation coefficient) was performed to analyze the correlations between the tests. A ROC curve was constructed to assess the best value for the Brasfield score that would indicate the presence of bronchiectasis on CT. Results: A total of 43 patients were evaluated, 19F/24M, 10.5 ± 4.7 years, with median Bhalla, Brasfield and SK scores of 10, 17 and 70, respectively. Mean values (% predicted) forced vital capacity (FVC), forced expiratory volume in one second (FEV1) and forced expiratory flow between 25 and 75% of vital capacity (FEF25-75%) were respectively 70.4 ± 26, 26 ± 59.2, 47.4 ± 35.8. There were significant correlations among almost all parameters studied. Only there was no statistically significant correlation between Z-6MWT and air trapping + mosaic perfusion (r = -0.35), FEV1 70% and SK (r = -0.04), FEV1 70% and Bhalla (r = -0.32), FEV1 70% and Brasfield (r = 0.14), FEV1 70% and Z-6MWT (r = 0.14). ROC curve determined that Brasfield score of 18 had the best sensitivity (83%), specificity (92%), positive predictive value (96%) and negative predictive value (71%) for detecting bronchiectasis on chest CT. Conclusions: These patients with cystic fibrosis had a wide variation in disease severity as assessed by clinical, radiographic, tomographic and functional scores. Despite this variation, there was a significant correlation between most methods used in the study. The correlations were not significant in patients with normal lung function or with mild obstructive lung disease, which may be related to a lower discriminate capacity between the different methods when pulmonary involvement is mild. In this study, patients with Brasfield score less than or equal to 18, had a probability of 83% to have bronchiectasis on chest CT. The six-minute walk test is a complementary method that can be used to assess the severity of patients with CF
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Månsson, Lars Gunnar. "Evaluation of radiographic procedures investigations related to chest imaging /." Göteborg, Sweden : Dept. of Radiation Physics, Göteborg University, 1994. http://catalog.hathitrust.org/api/volumes/oclc/35482139.html.
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Evanoff, Michael Geoffrey 1964. "Automatic identification of chest orientation in digital radiographic images." Diss., The University of Arizona, 1998. http://hdl.handle.net/10150/282811.
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Radiology departments are implementing conversion from the use of hard copy film in favor of digital imaging. New digital acquisitions are increasing the efficacy of radiological imaging. The outputs of new modalities such as magnetic resonance (MR) and computed tomography (CT) are digital. They both involve gathering information that allows reconstructing cross sectional projections of internal structures and displaying them as digital images. Other technologies, e.g., computed radiography (CR), can provide digital radiographic data that replaces analog projection radiography. To date, the processed digital data is still transferred to film to provide a typical radiographic film in appearance. The film is presented to the doctor for diagnostic review. The research in this dissertation is concerned with making a film-less department. It specifically addresses problems in presenting CR images to the physician. The goal of this research is to create a computer recognition algorithm that will automatically recognize the orientation and discriminate between the lateral and posteroanterior view of digital chest radiographs image. The algorithm maintains 91.9% accuracy rate. The recognition takes .15 second per image.
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Pinto, Lancelot. "Chest radiograph scoring systems for the diagnosis of Active Pulmonary Tuberculosis." Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=110727.
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Background: Chest radiography is often the only tool available for the investigation of tuberculosis (TB) suspects with negative sputum smears, thus playing a crucial role in clinical decision-making. However, chest radiographs lack specificity for TB, and their interpretation is subjective and not standardized, and therefore not highly reproducible. Efforts to improve the interpretation of chest radiography are warranted, especially with the growing use of digital radiology.Objectives: To systematically review the literature on the use of scoring systems to aid the diagnosis of active pulmonary TB (PTB), and to derive a new, simple scoring system using features noted on the Chest Radiograph Reading and Recording System (CRRS), a tool designed for the documentation of radiographic abnormalities in epidemiological surveys for PTB.Methods: A systematic review of the literature was performed to assess the utility of chest radiograph scoring systems for the diagnosis of PTB, and to use this information to derive a scoring system using the CRRS. Chest radiographs of outpatients with suspected PTB, consecutively recruited over 3 years at clinics in South Africa, were read by two independent readers using CRRS. Multivariable analysis was used to identify features significantly associated with culture-positive PTB, and these were assigned weights and used to generate a composite score.Results: A systematic review of the literature identified 12 studies that used radiographic features as part of scoring systems for the diagnosis of PTB. Six of these were tested in smear-negative patients. There was no scoring system found that involved the exclusive use of radiographic features. Upper lobe infiltrates and cavities were the radiographic features most commonly associated with the disease. The sensitivities of the scoring systems were uniformly high, but all of them lacked specificity. For the study in South Africa, 473 patients were included in the analysis. Large upper lobe opacities, cavities, unilateral pleural effusion and adenopathy were significantly associated with culture-confirmed PTB, had high inter-reader reliability, and received 2, 2, 1 and 2 points, respectively in the final score. When applied to all TB suspects, using a cut-off of ≥ 2, the score had a high negative predictive value (92%, 95%CI 87,95). Among TB suspects with negative sputum smears, the score correctly ruled out active disease in 214 of 229 patients (NPV 93; 95%CI 89,96) Conclusions: Existing radiographic scoring systems for the diagnosis of PTB appear to be sensitive, but lack specificity. The scoring system derived from CRSS is a simple and reliable tool that may be useful for ruling out active PTB in smear-negative patients. Validation studies are needed to confirm these initial findings.Contexte: La radiographie thoracique est souvent le seul outil disponible pour le dépistage de la tuberculose (TB) chez les patients ayant des frottis d'expectoration négatifs, lui donnant ainsi un rôle crucial dans la prise de décision clinique. Toutefois, les radiographies thoraciques manquent de spécificité pour la tuberculose, et leur interprétation est subjective et non standardisée, et donc n'est pas très reproductible. Les efforts visant à améliorer l'interprétation de la radiographie pulmonaire sont justifiés, surtout vu l'utilisation croissante de la radiologie numérique.Objectifs: Les objectifs incluent une recherche systématique de la littérature sur l'utilisation des systèmes de notation pour aider le diagnostic de la tuberculose pulmonaire active (TBP), et d'en tirer un nouveau système de notation simple à partir du Chest Radiograph Reading and Recording System (CRRS) (Système de Lecture et Notation des radiographies thoraciques), un outil conçu pour la documentation des anomalies radiologiques dans les études épidémiologiques sur la TBP.Méthodes: Une recherche systématique de la littérature a été effectuée pour évaluer l'utilité des systèmes de notation des radiographies thoraciques pour le diagnostic de la TBP, et pour utiliser ces informations pour dériver un système de notation à partir du CRRS. Les radiographies thoraciques de patients ambulatoires suspects de TBP, recrutés consécutivement sur 3 ans dans des cliniques en Afrique du Sud, ont été lues par deux lecteurs indépendants en utilisant CRRS. Une analyse multivariée a été utilisée pour identifier les caractéristiques significativement associées à la TBP à culture positive, et ceux-ci ont reçu une importance respective et ont été utilisé pour générer un score composite.Résultats: Une recherche systématique de la littérature a identifié 12 études qui ont utilisé des systèmes de notation pour analyser les caractéristiques radiographiques dans le cours du diagnostic de la TBP. Six d'entre elles comprenaient seulement des patients à frottis négatif. Aucun système de notation ne comprenait l'usage exclusif des caractéristiques radiographiques. Des cavités et des infiltrats dans les lobes supérieurs étaient les caractéristiques radiographiques les plus couramment associées à la maladie. Les sensibilités des systèmes de notation étaient uniformément élevées, mais chacun d'eux manquait de spécificité.Dans l'étude en Afrique du Sud, 473 patients ont été inclus dans l'analyse. Les grandes opacités du lobe supérieur, les cavités, un épanchement pleural unilatéral ainsi que la présence d'adénopathie étaient significativement associés à la TBP confirmée par culture, avaient un haut taux de fiabilité entre lecteur, et ont reçu 2, 2, 1 et 2 points, respectivement dans le final. Lorsqu'appliqué à tous les cas suspects de tuberculose, en utilisant un seuil de ≥ 2, le score avait une forte valeur prédictive négative (92%, IC 95% 87-95). Parmi les suspects de TB à frottis négatifs, le score a correctement exclu la présence de maladie active dans 214 des 229 patients (VPN 93, 95% CI 89-96).Conclusions: Les systèmes actuels de notation radiographiques pour le diagnostic de TBP semblent être sensibles, mais manquent de spécificité. Le système de notation dérivée de la CRSS est un outil simple et fiable qui peut être utile pour exclure la TBP active chez les patients à frottis négatif. Des études de validation sont nécessaires pour confirmer ces premiers résultats.
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Robinson, John. "Factors influencing pulmonary nodule detection on a postero-anterior chest radiograph." Thesis, The University of Sydney, 2020. https://hdl.handle.net/2123/22603.
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Lung cancer deaths are predicted to double by 2035, and with 60% of these deaths occurring in the Western Pacific and South East Asia regions, chest radiography remains an important modality in the detection of non-small cell lung cancers (NSCLC). The interplay of visual perception and cognition on the detection of a lung nodule is studied and demonstrates that it is moderated by the radiologists’ specialisation. The thesis focuses on three studies investigating: priming action via a word association (nodule) on the radiologists’ cognition and visual perception; the influence of radiologists’ expertise on detecting nodules and the impact of grey-scale inversion on the detection of subtle nodules. Additionally, when the location of false-positives (FP) in the word association study were mapped on a CXR, a distinct pattern emerged. The concluding study identified that grey-scale inversion can be utilised to enhance nodule detection on primary class monitors. The thesis has established a link through the priming action of the word association. The priming actions results in a significant increase in the FPs on nodule-free and nodule-containing images with an overall significant reduction in the JAFROC figure-of-merit (FOM). The FP locations marked by the radiologists closely matches where common lung cancers are typically missed on a CXR and NSCLC occur. Further, the thesis has identified that thoracic radiologists can detect more subtle nodules than general radiologists. The thesis concludes that the wording of the clinical history can have a variable effect on CXR reporting. It increases the FPs in the case of searching for nodules creating a priming bias. Grey-scale inversion is a useful tool for radiologists to employ to assist them with identification of lung nodules of relatively low luminance value. Further education for radiologists is necessary to better understand the effects of priming upon their interpretation of CXRs.
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Zhang, Hui. "Temporal subtraction of chest radiograph using graph cuts and free-form deformations." Click to view the E-thesis via HKUTO, 2007. http://sunzi.lib.hku.hk/hkuto/record/b40203451.
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Richter-Joubert, Lisel. "Assessment of airway compression on chest radiographs in children with pulmonary tuberculosis." Master's thesis, University of Cape Town, 2018. http://hdl.handle.net/11427/29690.
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Study rationale: Diagnosis of pulmonary tuberculosis (PTB) in children relies heavily on chest radiography as sputum samples are difficult to obtain and only yield positive results in 30-74% of children treated for PTB. However, radiological signs between lower respiratory tract infections (LRTI) and PTB overlap considerably and there is a wide inter-observer agreement in the detection of lymphadenopathy, considered the hallmark of PTB. Small pliable paediatric airways are easily compressed by enlarged lymph nodes. Unlike lymph nodes, however, the lucent airways contrast against the surrounding mediastinal structures on radiographs, thus airway compression may serve as a more objective criterion for diagnosing PTB. Many studies have reviewed the radiographic features of PTB in children but few included airway compression or used a control group and none have evaluated inter-observer agreement. Objective: To investigate frequency and inter-observer agreement of airway compression on chest radiographs in children with PTB compared to those with another LRTI. Methods: Chest radiographs of children admitted to Red Cross War Memorial Children’s Hospital with suspected PTB were read by two readers according to a standardised format and a 3rd when there was disagreement. Radiographs of children with definite PTB were compared to those with another LRTI. Frequency and location of airway compression were evaluated. Findings were correlated with human immunodeficiency virus (HIV) infection and age. Inter-observer agreement was assessed using kappa statistic. Results: Radiographs of 505 children (median age 25.9 months [IQR 14.3-62.2]) were reviewed; 97/505 (19%) children were HIV-infected. Airway compression occurred in 54/188 (28.7%) definite PTB cases versus 24/317 (7.6 %) of other LRTI cases (OR 4.9; 95%CI 2.9–8.3). The left main bronchus was most affected in 51/493 (10.3%). A higher frequency of airway compression occurred in infants at 22/101 (21.8%) compared to 56/404 (13.9%) in older children (OR 1.7; 95%CI 1.00–3.00). No association between airway compression and HIV infection was found. Inter-observer agreement ranged from none to fair (kappa of 0.0-0.4). Discussion: The overall frequency of airway compression in definite PTB is compatible with reports in the literature. Although airway compression used alone is not a specific sign, if seen on radiographs, there is a strong correlation with PTB compared to other LRTI with infants at higher risk due to their smaller airways. Contradictory to other studies, our study showed the left main bronchus to be affected twice more commonly than the bronchus intermedius in both age groups. This is thought to be due to different patient selection. Confirming reports in the literature, no significant association between airway compression and HIV status was found. A disappointing finding was the poor inter-observer agreement. Contributing aspects include the lack of standardised criteria in the definition of airway compression and suboptimal visualisation of the airways on standard chest radiographs due to patient, technical and post processing factors. Conclusion: There is a strong association between airway compression on chest radiographs and definite PTB, particularly in infants, irrespective of HIV status. However, its clinical use as an objective criterion in the diagnosis of PTB is limited by poor inter-observer agreement.
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Huang, Zhao-Wei. "Automated Scoring for Cystic Fibrosis in Chest Radiographs based on Deep Learning Methods." Thesis, The University of Sydney, 2019. http://hdl.handle.net/2123/20401.
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Cystic fibrosis (CF) is a genetic disease that attacks multiple organs. It is an incurable illness in the respiratory system, with about one-sixth of native Australians suffering from it. Cystic Fibrosis Community Care* shows that 1 in 25 people in Australia are carrying defective CF genes and nearly 90 babies each year are born with CF. Clinicians diagnosed the pulmonary CF mainly through chest radiographs (CXRs). This study proposes a novel computer-aided diagnostic (CAD) framework with deep learning features for automated scoring of CF in CXRs. Within this framework, key components and algorithms are developed, examined and refined to achieve the best scoring performance as compared to human observers. We present a framework to analyse chest radiographs for cystic fibrosis using machine learning methods. We compare the representational power of deep learning features with traditional texture features. Specifically, we respectively employed VGG-16-based deep learning features and Tamura- and Gabor-filter-based textural features to represent the cystic fibrosis images. We demonstrate that VGG-16 features perform best, with a maximum agreement of 82%. In addition, Tamura features’ accuracy of Tamura reaches 78%. We also present a framework to analyse chest radiographs for cystic fibrosis using deep learning methods. We compare the effectiveness of two typical deep convolution neural networks, ResNet-152 and VGG-16, both of which are transferred the knowledge learned from the ChestX-ray14 dataset. We had the best scoring accuracies of 91% for ResNet-152 and 86% for VGG-16, 12.3% and 3.6% respectively better than the networks pre-trained by natural images on ImageNet. The overall best performance was exhibited by transfer-learning-based ResNet-152 with random forest classifier. It achieved 91.5% accuracy for classification across three levels of scoring (10, 15 and 20).
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Narayanan, Barath Narayanan. "New Classifier Architecture and Training Methodologies for Lung Nodule Detection in Chest Radiographs and Computed Tomography." University of Dayton / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1508237793168873.
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Oliveira, Ana Luiza da Rosa de. "Avaliação de dose de entrada na pele em pacientes pediátricos através de medidas dosimétricas." Universidade Tecnológica Federal do Paraná, 2008. http://repositorio.utfpr.edu.br/jspui/handle/1/1296.
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A grande utilização de exames de diagnóstico por imagem em crianças trouxe à tona a preocupação com a crescente dose de radiação absorvida na realização de um exame radiográfico. O objetivo desta pesquisa foi realizar avaliação das práticas de raios X na radiologia pediátrica, visando a otimização dos procedimentos radiológicos e a produção de imagens com qualidade para o diagnóstico com a menor dose ao paciente. A metodologia foi baseada no acompanhamento de exames pediátricos e medidas dosimétricas através do uso de dosímetros termoluminescentes TLDs e software específico (DoseCal) para a constatação da realidade dos serviços de radiologia pediátrica. Medidas de pacientes pediátricos em exames radiográficos de tórax foram realizadas em um hospital público de Curitiba e em uma clínica em Cascavel. Grupos com diferentes faixas etárias foram formados na avaliação de exames rotineiros de tórax nas projeções AP/PA e LAT, e ossos da face na projeção lateral, onde foram divididos em grupos de 0-1 ano, 1-5 anos, 5-10 anos e 10-15 anos. As doses obtidas através do software DoseCal foram comparadas entre si para determinar sua variabilidade. A DEP determinada pelos TLDs foi comparada com os valores de referência dados pela comunidade européia para verificar as doses utilizadas. Os valores de dose para crianças de até 1 ano apresentaram-se altos em comparação com os demais grupos avaliados, um fator justificado em partes pela limitação dos equipamentos utilizados. Na radiologia convencional os valores obtidos através dos TLDs foram satisfatórios, obedecendo a referência máxima descrita pela comissão européia. Na radiologia digital indireta obtivemos valores acima dos referenciados, fator este resultante da implantação e da adaptação das técnicas radiológicas a nova forma de captação de imagem. Concluí-se que o aprimoramento técnico das equipes em radiologia pediátrica é uma das melhores maneiras de se obter bons resultados na diminuição da dose.The great use of examinations of diagnosis for image in children brought the concern with the increasing dose of radiation absorbed in the accomplishment of a radiographic examination. The objective of this research is to carry through evaluation of the practical ones of x-rays in pediatric radiology, aiming at to optimize the radiological rocedures and the production of images with quality for the diagnosis with the lesser dose to the patient. The methodology is based on the accompaniment of pediatric examinations and dosimetry measures through the use of dosemeters TLD and specific software (DoseCal) for the evidence of the reality in a radiology service. Measures of pediatric patients in radiographic examinations of thorax had been carried through in a public hospital in the Curitiba. Groups with different age groups had been formed in the evaluation of routine examinations of thorax in projections AP/PA and LAT, where they are divided in groups of 0-1 year, 1-5 years, 5-10 years and 10-15 years. Part of the carried through examinations had been evaluated with thermoluminescence dosemeters TLD-100 for the collection of the entrance surface dose (ESD). The measured doses are compared with the gotten ones with the DoseCal software, that makes the calculation of dose for each patient from the income of the device of rays X. The ESD is evaluated always that it has diagnostic quality in the radiographic image. The objective is to verify if the minimum requirements had been reached, for a good quality of image and bringing a small dose to the patient, as party to suit of to optimize procedures.
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Lee, Min-Zhao. "Computer-Aided Diagnosis in Radiology: Medical Image Analysis for the Scoring of Chest Radiographs in Cystic Fibrosis." Thesis, The University of Sydney, 2015. http://hdl.handle.net/2123/14101.
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Cystic fibrosis (CF) is one of the most common life-threatening genetic disorders worldwide and in Australia, causing considerable morbidity and mortality. Multiple organs are affected, including lungs in which a typical pattern of changes occurs, with progressive inflammatory thickening of the airways and destruction of alveoli. Clinicians assess disease severity using a combined score that includes radiological imaging. The Shwachman-Kulczycki scoring system used in Australia classifies chest radiographs (CXRs) into five categories. Determination of the score is still performed entirely by clinicians, and so an automated scoring system is an innovation that would provide an objective measure of the CXR abnormalities. This study proposed a novel computer-aided diagnostic (CAD) framework for fully-automated scoring of paediatric CXRs in CF. A patch-based method for segmentation was implemented and evaluated. PBS of CXRs achieved median overlap of 0.939 using a 70-image reference set and voting between the 13 nearest neighbours. Performance degraded gracefully, even for large reductions in bit depth and reference set size. Texture features were selected and examined for their ability to discriminate disease severity. Tamura features, local binary patterns, grey-level co-occurrence matrix-derived features and Gabor filtering were used, as inputs to linear discriminant analysis and support vector machine (SVM) classification. A spatial-domain band-pass filter was also developed to enhance the sensitivity of the texture analysis. The overall best classification performance, using Tamura features and SVM, was 75% agreement with clinician scores for classification among three levels (mild, moderate, severe), and 90% agreement for mild-versus-severe classification. This level of performance was similar to the level of human interobserver agreement for the dataset.
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Wen, Cathlyn Y. "The evaluation of chest images compressed with JPEG and wavelet techniques." Thesis, This resource online, 1996. http://scholar.lib.vt.edu/theses/available/etd-08222008-063743/.
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Pietrzyk, Mariusz W. "Spatial frequency analysis of the perceptual features involved in pulmonary nodule detection and recognition from posterior-anterior chest radiographs." Thesis, Lancaster University, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.556697.
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RATIONALE AND OBJECTIVES: Radiological error due to the incorrect interpretation of medical images still occurs in current practice, and continues to be reported both in laboratory and clinical experimental conditions. In general radiological practice error rates range from 3 - 5%. However, that scale reaches up to 30% for detection of some early pulmonary cancers. Computer-Aided Detection (CAD) algorithms have been proposed to support human observers in verifying their choices. Although CAD systems might help in certain situations, its general implementation in clinical practice is still controversial. Perceptual studies involving psychophysical approaches to the error problem may give some insight into the gap between advances in image processing and the nature of radiological expertise. Moreover, some neuroscientific evidence underlines the importance of processing spatial frequency properties of visual stimuli that is carried out by the Human Visual System (HVS). This has provided the inspiration for Spatial Frequency Analysis of certain Regions of Interest (ROI) selected by human observers in medical image interpretation in a number of studies. Such studies have been conducted in mammography focusing on the relationship between the physical properties, the type of radiological outcomes and the dwelling time. The spatial frequency features in mammograms have very specific features however, and this leads to the question of whether the results for mammography could be generalised to other medical images. RESEARCH AIMS: This study aims to investigate the perceptual criteria used in decision-making processes in pulmonary lung nodule detection from Posterior-Anterior (PA) Chest Radiographs (CxR). Moreover, the development in radiological expertise has been taken into account by comparing the results obtained from subjects with different levels of experience in the field. MATERIALS AND METHODOLOGY: Ten participant observers were selected from each of the following groups: radiologists and reporting radiographers (experts), radiography students (two levels of novices) and those without any relevant experience (naive). 11 ~ •• ------------~=== Subjects participated in the eye tracking experiment during lung nodule detection from a set of PA radiographs with a 50% prevalence of pathology. Twenty radiological cases were included in the data bank., where ten contained one to five nodules. The assessment of performance for each individual was calculated based on Jack-knife Alternative Free-response Receiver Operating Characteristic Figure of Merit (JAFROC FOM). Eye tracking data was used to divide images into areas of foveal visual attention distribution from the most dwelled to totally ignored Regions of Interest (ROI). These selected sites were analysed in terms of spatial frequency properties using 2D Stationary Wavelet Packets Transform (SWPT) frames by Dubieties functions up to three levels of decomposition. The logarithm of energy carried by each wavelet coefficient represents the amount of visual information coded by the spatial frequency range ω1 = f(ωx/ωy) in a particular orientation θi = g(tag(ωx/ωy)) and is called Spatial Frequency Band (SFBj). A reduction procedure was applied to eliminate redundancy in information coding by a set of SFB. Thus, 84 bands obtained from the third level of decomposition were reduced to twenty nine bands. The degree of dissimilarity in spatial frequency domains between selected regions was explored by statistical analysis on wavelet representations at the sites of subjects' responses. The locality of selected sites was limited by the foveal Field of View (FOV). The dissimilarities between wavelet representations were measured according to the number of non-redundant SFBj within which significant differences (p<0.05) were found according to an analysis of variance (ANOV A) with post hoc test. The statistical analysis embraced subject-related factors (expertise level, JAFROC FOM, dwell time) and image-based features (nodule detectability, conspicuity, localization and spatial frequency description). These factors were considered as independent variables in visual attention distribution and decision-sites studies. RESULTS: The correctness of the second or higher order responses were highly correlated with the category of first decision-outcomes made on the case. That correlation shows the probability of accurate end-point decisions related to the first decision. Experts are more accurate in dedicating visual attention to the more relevant areas containing pulmonary nodules. Significant differences were found in the spatial frequency domain between nodule-containing regions which have been fixated and those which were left without focal attention. The JAFROC FOM calculation based on overall performance characterizes the more experienced subjects as being more accurate in decision-making and less variable in FOM value within a group. Moreover, the high accuracy of subject performance was correlated with the allocation of visual attention in normal regions which are more similar to the nodule-containing sites,.in terms of the spatial frequency features. The experts' ability in distinguishing the most attractive True- Negative (TN) from True-Positive (TP) avoiding False-Positive (FP) was proven with differences at the spatial frequency level. High correlation between the correctness of a first overt decision made on certain cases and the .quality performance was found significant (r=D. 75), The category of the first response effects the perceptual criteria applied to form the final decision outcome. CONCLUSIONS: The main contribution to knowledge of this work is that for the first time the SF A was conducted on a radiological task other than mammography. The work lends significant weight to the argument that spatial frequency channels coded through a wavelet paradigm are a characterising feature of visual perception and that this is phenomenon is generalisable to areas of radiology other than breast imaging, where mammographs are quite unique in terms of image-based features compare to pictures obtained from other medical irnaging modalities. Also, this work contributes an extension to previous studies on non-expert groups through investigation into trends in development of radiological experience. There is some agreement with the conclusions presented by others who suggest that experts may use specific neural connections - a set of spatial frequency channels tuned to specific object detection - during visual searching in a radiological task.
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Rabbani, Seyedeh Parisa. "Effect of image variation on computer aided detection systems." Thesis, KTH, Skolan för teknik och hälsa (STH), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-123546.
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Computer Aided Detection (CAD) systems are expecting to gain significant importance in terms of reducing the work load of radiologists and enabling the large screening programs. A large share of CAD systems are based on learning from examples, to enables the decision making between the images with or without disease. Images are simplified to numerical descriptors (features vectors) and the system is trained with these features. The common practical problem with CAD systems is training the system with a data from a specific source and testing it on a data from a different source; the variations between sources usually affect the CAD system function. The possible solutions for this problem are (1) normalizing images to make them look more equal, (2) choosing less variation sensitive features and (3) modifying the classifier so that it classifies the data from different sources more accurately. In this project the effect of image variations on the developed CAD system on chest radio graphs for Tuberculosis is studied at Diagnostic Image Analysis Group. Tuberculosis is one of the major healthcare problems in some parts of the world (1.3 million deaths in 2007) [1]. Although the system has a great performance on the train and test data from the same source, using different sub dataset for training and testing the system does not lead to the same result. To limit the effect of image variation of the CAD systems three different approaches are applied for normalizing the images: (1) Simple normalization, (2) local normalization and (3) multi band local normalization. All three approaches enhance the performance of the system in case of various sub datasets for training and testing purposes. According to the improvement achieved by applying normalization it is suggested as a solution for the stated problem above. Although the outcome of this study has satisfactory result, there is always room for further investigations and studies; in specific testing different approaches for finding less variation sensitive features and modifying the classification procedure to a more variation tolerant process.
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Quekel, Lorentz Godfried Bernhard Alexander. "Detectability of early lung cancer on the chest radiograph a study on miss rate and observer performance in clinical practice /." Maastricht : Maastricht : Universiteit Maastricht ; University Library, Maastricht University [Host], 2001. http://arno.unimaas.nl/show.cgi?fid=7620.
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Hilbert, Timothy J. "Factors associated with Reader Disagreement in a 20-year Radiology Study." University of Cincinnati / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1242835896.
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Nyoka-Mokgalong, Simangele Cecilia. "A retrospective audit of the clinical value of routine chest radiographs in the first 24 hours after cardiac surgery using medical records." Master's thesis, University of Cape Town, 2016. http://hdl.handle.net/11427/20682.
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Routine postoperative chest radiography after cardiac surgery is a common practice, although studies, both prospective and retrospective, conducted in their majority outside Africa, have shown that these chest radiographs are of low clinical value, mainly due to limited impact on patient management. Following cardiac surgery and admission to ICU, chest radiographs are obtained in order to ensure proper position of all invasive devices such as endotracheal tubes, invasive catheters as well as nasograstric tubes, and to exclude possibility of a pneumothorax, atelectasis, infiltrates, and other potential respiratory complications associated with ventilatory support. Following cardiac surgery, there are other elements that require assessment: mediastinum (for widening due to bleeding), pleural space (for presence of fluid or air) and cardiovascular system (for presence of signs of failure). Specific to cardiac surgery is the post-operative pulmonary dysfunction (PPD), where systemic inflammatory response due to cardiopulmonary bypass is the main culprit [Milot J et al, 2001] - leading to acute lung injury. Over and above the usual cardiovascular diseases that require surgical intervention, in Sub-Saharan Africa, inflammatory and infective conditions such as pulmonary tuberculosis, pulmonary hydatid disease, and pulmonary complications of HIV infection, are very prevalent. These pre-existing lung pathologies predispose patients to postoperative pulmonary complications after cardiac surgery. This audit investigates the role and importance of bedside chest X-rays in post operative care of cardiac surgery patients that come from a population group where lung pathology is quite prevalent.
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Wang, Wei. "Image Segmentation Using Deep Learning Regulated by Shape Context." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-227261.
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In recent years, image segmentation by using deep neural networks has made great progress. However, reaching a good result by training with a small amount of data remains to be a challenge. To find a good way to improve the accuracy of segmentation with limited datasets, we implemented a new automatic chest radiographs segmentation experiment based on preliminary works by Chunliang using deep learning neural network combined with shape context information. When the process was conducted, the datasets were put into origin U-net at first. After the preliminary process, the segmented images were then repaired through a new network with shape context information. In this experiment, we created a new network structure by rebuilding the U-net into a 2-input structure and refined the processing pipeline step. In this proposed pipeline, the datasets and shape context were trained together through the new network model by iteration. The proposed method was evaluated on 247 posterior-anterior chest radiographs of public datasets and n-folds cross-validation was also used. The outcome shows that compared to origin U-net, the proposed pipeline reaches higher accuracy when trained with limited datasets. Here the "limited" datasets refer to 1-20 images in the medical image field. A better outcome with higher accuracy can be reached if the second structure is further refined and shape context generator's parameter is fine-tuned in the future.Under de senaste åren har bildsegmentering med hjälp av djupa neurala nätverk gjort stora framsteg. Att nå ett bra resultat med träning med en liten mängd data kvarstår emellertid som en utmaning. För att hitta ett bra sätt att förbättra noggrannheten i segmenteringen med begränsade datamängder så implementerade vi en ny segmentering för automatiska röntgenbilder av bröstkorgsdiagram baserat på tidigare forskning av Chunliang. Detta tillvägagångssätt använder djupt lärande neurala nätverk kombinerat med "shape context" information. I detta experiment skapade vi en ny nätverkstruktur genom omkonfiguration av U-nätverket till en 2-inputstruktur och förfinade pipeline processeringssteget där bilden och "shape contexten" var tränade tillsammans genom den nya nätverksmodellen genom iteration.Den föreslagna metoden utvärderades på dataset med 247 bröströntgenfotografier, och n-faldig korsvalidering användes för utvärdering. Resultatet visar att den föreslagna pipelinen jämfört med ursprungs U-nätverket når högre noggrannhet när de tränas med begränsade datamängder. De "begränsade" dataseten här hänvisar till 1-20 bilder inom det medicinska fältet. Ett bättre resultat med högre noggrannhet kan nås om den andra strukturen förfinas ytterligare och "shape context-generatorns" parameter finjusteras.
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Breuninger, Marianne [Verfasser], Klaus [Akademischer Betreuer] Reither, and Dirk [Akademischer Betreuer] Wagner. "Diagnostic accuracy of computer-aided detection and a scoring system for pulmonary tuberculosis in chest radiographs : a validation study from Sub-Saharan Africa." Freiburg : Universität, 2016. http://d-nb.info/1122830653/34.
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Oliveira, Virgilio de Araujo. "Apresentação radiológica da tuberculose pulmonar em pacientes transplantados renais do Hospital das Clínicas da Faculdade de Medicina de Botucatu – UNESP." Botucatu, 2018. http://hdl.handle.net/11449/154539.
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Orientador: Sergio Marrone RibeiroResumo: Introdução: Apesar dos avanços na compreensão do acometimento da tuberculose pulmonar na população de transplantados renais, são escassos na literatura os estudos que visam a entender como esta patologia se manifesta através dos métodos de imagem nesta população específica, já que com a imunossupressão podem haver apresentações atípicas de doença, como já é bem estabelecido em outras infecções. Propósito: Estabelecer o número de casos de tuberculose pulmonar ativa na população de transplantados renais de nossa instituição, bem como analisar as manifestações radiológicas desta patologia nas radiografias e nas tomografias computadorizadas de alta resolução de tórax destes pacientes, buscando avaliar padrões de acometimento nestes métodos de imagem e se estes são sobreponíveis ou não à tuberculose pulmonar na população geral Métodos: Foram analisados os prontuários eletrônicos dos pacientes transplantados renais no período de janeiro de 2013 a julho de 2016 em busca de pacientes que tenham apresentado tuberculose pulmonar ativa neste período. Foram colhidos dados do prontuário eletrônico e também analisadas as radiografias e tomografias de tórax nestes pacientes. Resultados: Na população de 769 pacientes transplantados renais de nossa instituição foram encontrados 4 casos de tuberculose pulmonar ativa. As tomografias forneceram informações adicionais às radiografias em 100% dos casos analisados. As manifestações pulmonares da tuberculose pulmonar avaliadas nas tomografias dos qu... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Introduction: Despite the advances in understanding the involvement of pulmonary tuberculosis in the renal transplant population, there are few studies in the literature that aim to understand how this pathology manifests itself through imaging methods in this specific population, since with immunosuppression there may be atypical presentations of disease, as is well established in other infections. Purpose: To establish the number of cases of active tuberculosis in the population of renal transplant patients of our institution, as well as to describe the radiological manifestations of active pulmonary tuberculosis in the thoracic radiography and high resolution computed tomography of patients with active pulmonary tuberculosis, aiming to establish patterns of involvement in these imaging methods and whether they are overlapping or not to the pulmonary tuberculosis in general population. Methods: The electronic medical records of renal transplant patients were analyzed from January 2013 to July 2016 in search of patients who had active pulmonary tuberculosis in this period. Data were collected from the electronic medical record and the thoracic radiography and tomography were also analyzed in these patients. Results: In the population of 769 renal transplant patients from our institution, 4 cases of active pulmonary tuberculosis were found. Tomography provided additional information to radiography in 100% of the cases analyzed. The pulmonary manifestations of pulmonary tuberc... (Complete abstract click electronic access below)
Mestre
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Blumberg, Detlef. "Diagnostik pneumonischer Veränderungen in der Röntgenthoraxübersichtsaufnahme bei Patienten mit ARDS." Doctoral thesis, Humboldt-Universität zu Berlin, Medizinische Fakultät - Universitätsklinikum Charité, 1999. http://dx.doi.org/10.18452/14421.
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Anlass dieser Studie war die Erfassung und Beurteilung radiologischer Genauigkeit in Thoraxübersichtsaufnahmen bei der Diagnostik von ARDS und Pneumonie. Dazu wurden von 84 Patienten (35 mit ARDS, 46 Patienten mit zusätzlicher Pneumonie) drei aufeinander folgende Aufnahmen befundet und hinsichtlich verschiedener radiomorphologischer Merkmale qualitativ, quantitativ und statistisch analysiert. Es konnte nachgewiesen werden, daß es für eine sichere Befundung von Röntgenthoraces keine statistisches Korrelat gibt (p > 0.6). Die Irrtumswahrscheinlichkeit für falsch positive und falsch negative Ergebnisse lag bei 78% und entsprach dabei den Angaben in der Literatur. Die Ergebnisse unterstreichen zudem die Feststellung, daß auch Serienaufnahmen nicht zur Verbesserung der diagnostischen Sicherheit führen, die Wertigkeit von Röntgenthoraxaufnahmen beim ARDS daher nur im Rahmen einer allgemeinen Verlaufsbeurteilung zu sehen ist.In addition to general clinical factors involved in the course of ARDS, the aspect of pneumonia superimposed on ARDS, its incidence, the predisposing factors and the underlying sources of infection were to be analysed and the reasons for the different radiological interpretation of this disease reported in literature and practice were to be established. Three consecutive radiographic chest views of 84 patients (35 with ARDS, 49 with ARDS and primary or secondary pneumonia) which were optically and statistically comparable as regards their radiological features were reviewed and evaluated comparatively by discriminance analysis. The study showed that no statistical correlate exists (p > 0.6) for a reliable interpretation of adiographic chest views with regard to ARDS and/or ARDS with additional pneumonia. Furthermore, the results underline the fact that even a series of films obtained within a 24-hour interval cannot help to improve the diagnostic safety and that, consequently, radiographic chest views are of value only for a general assessment of the course of ARDS, whether with or without accompanying pneumonia.
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Fonseca, Afonso Ueslei da. "Desenvolvimento de técnicas de pré-processamento de radiografias digitais de tórax infantil : uma abordagem orientada a segmentação para sistemas de diagnóstico assistido por computador." Universidade Federal de Goiás, 2017. http://repositorio.bc.ufg.br/tede/handle/tede/7079.
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According to the World Health Organization (WHO), more than 900,000 children, younger than five years old, have died in 2015 due to pneumonia. Many of these deaths could be avoided with earlier and more accurate diagnosis to provide proper medicine administration. Chest radiography is one of the most recommended test by the WHO in order to detect childhood pneumonia, and it is commonly used in computer aided diagnostic (CAD) systems. A science role is to develop systems that require a more precise medical diagnosis and treatment cost reducing, but mainly death rate decreasing. It is highlighted that quality radiography demands equipments very well installed and calibrated and staff trained to handle them. However, due limited budget resources, mainly in most vulnerable areas, the image quality is significantly damaged, so turning the medical diagnosis harder. Therefore, this work presents a method composed of a set of preprocessing techniques for pediatric radiography. These techniques intend to have simple implementation and low computational cost. The main goal of this work is to increase performance, accuracy and robustness of CAD systems, to improve database standardization and also to collaborate with the professionals training. Thus, techniques were developed, such as, visual quality enhancement, removal of unnecessary or confidential information, reconstruction of degraded areas due to the information removal, orientation correction and definition of a region of interest. All techniques were evaluated using a children chest X-ray database divided into three classes and results show significantly improve when compared to methods presented in literature. We expect these contributions will assist to development and improvement of new systems, construction of more standardized databases, staff training and the development of new techniques.
Segundo a Organização Mundial de Saúde (OMS) mais de 900 mil crianças, menores de cinco anos, foram a óbito em 2015, devido a pneumonia. Muitas dessas mortes poderiam ser evitadas com um diagnóstico mais preciso, precoce e com correta administração de medicamentos. A radiografia de tórax é um dos exames preconizados para detecção de pneumonia pela OMS, sendo comumente usada em sistemas de diagnóstico assistido por computador (CAD). Desenvolver sistemas que apoiem diagnóstico médico mais preciso, reduzam custos de tratamento e principalmente diminuam o número de óbitos é um papel da ciência. Destaca-se que radiografias de qualidade requerem equipamentos devidamente instalados/calibrados e pessoal capacitado para opera-los. Todavia, dado os recursos financeiros limitados, principalmente em áreas mais vulneráveis, a qualidade das imagens fica significativamente comprometida, dificultando o trabalho de diagnóstico pelo médico. Assim, este trabalho traz um método composto por técnicas de pré-processamento de radiografias de tórax pediátricas. As técnicas foram idealizadas para serem de simples implementação e baixo custo computacional. Os principais objetivos do trabalho são promover ganho de performance, acurácia e robustez aos sistemas CAD, favorecer a construção de bases de imagens padronizadas e além disso colaborar com o treinamento de profissionais de saúde. Para atingir esses objetivos foram desenvolvidas técnicas de melhoria da qualidade visual, remoção de informações desnecessárias ou confidenciais e reconstrução das áreas degradadas decorrente da remoção dessas informações, correção de orientação e definição de regiões de interesse. Esse método foi avaliado utilizando uma base de radiografias de tórax infantil divida em três classes e resultados mostram ganhos significativos em comparação a métodos presentes na literatura. Espera-se que essas contribuições favoreçam o aperfeiçoamento de sistemas, construção de bases mais padronizadas, treinamento de profissionais e surgimento de novas técnicas.
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Min-HsinHuang and 黃敏信. "Carina Detection on Chest Radiography." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/54706271893895493709.
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碩士國立成功大學
醫學資訊研究所
100
It is important to check the position of the endotracheal tube on the portable chest radiography for patients in the intensive care units. The position of carina is not easy to identify on portable chest radiography due to the low image contrast and abundant noise at this region of interest. In this paper, a novel method is proposed to identify the position of carina. The proposed method is integrated with the rule-based image segmentation, contrast enhancement, selective thresholding, and morphological image processing. Experimental results show that the proposed method is robust and the success rate is 92.1%. It can be used to enhance patient safety by early detection and prompt correction of improper position of the endotracheal tube.
49
Pedersen, C. C. E., Maryann L. Hardy, and A. D. Blankholm. "An Evaluation of Image Acquisition Techniques, Radiographic Practice, and Technical Quality in Neonatal Chest Radiography." 2018. http://hdl.handle.net/10454/16523.
Full textAbstract:
noBackground Neonatal chest radiography is a frequently performed diagnostic examination, particularly in preterm infants where anatomical and/or biochemical immaturity impacts on respiratory function. However, the quality of neonatal radiographic images has been criticized internationally and a prevailing concern has been that radiographers (radiologic technologists) fail to appreciate the unique nature of neonatal and infant anatomical proportions. The aim of this study was to undertake a retrospective evaluation of neonatal chest radiography image acquisition techniques against key technical criteria. Methods Hundred neonatal chest radiographs, randomly selected from all those acquired in 2014, were retrospectively evaluated. Inclusion criteria for radiographs acquisition were as follows: anterior-posterior supine; within 30 days of birth; and with all preprocessed collimation boundaries visible. Image evaluation was systematically undertaken using an image assessment tool. To test for statistical significance, Student's t-test, χ2 test, and logistic regression were undertaken. Results Only 47% of the radiographs were considered straight in both upper and lower thoraces. The cranial collimation border extended beyond the upper border of the third cervical vertebra in 30% of cases, and the caudal border extended below the lower border of the first lumbar vertebra in 20% of cases, suggesting high possibility of neonatal overirradiation. Upper thorax rotation was significantly associated with head position (χ2 = 10.907; P < .001) as has been stated in many published textbooks internationally, but arm position had no apparent influence on rotation of the upper thorax (χ2 = 5.1260; P = .275). Birth weight was associated with accurate midline centering of central ray (logistic regression; OR = 1.0005; P = .009; CI, 1.00139–1.000957) with greater accuracy observed in images of neonates with higher birth weight. Conclusion This study has highlighted areas for neonatal chest radiography improvement. Importantly, the findings bring into question commonly advocated radiographic techniques relating to arm positioning and assessment of rotation while confirming the importance of other technical factors. These findings begin the work toward developing the evidence base to underpin neonatal chest radiograph acquisition, but further prospective work and multicenter/multinational data comparison are required to confirm the findings.
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HUANG, TE-FA, and 黃德發. "Scatter Radiation Measurement By Chest Radiography Array Arrangement." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/c2aydd.
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碩士中臺科技大學
醫學影像暨放射科學系暨研究所
105
X-ray examination has been playing an important role to detect early lesion for centuries, the unwanted radiation irritates to patient and relatives is much concerned. The purpose of this study focused on the detection of unwanted radiation by using TLD-100H to record the space radiation distribution. 80 TLD-100H (Harshaw, USA) were allocated in the matrix of space of 140×180 cm², 20 cm each. A LUNGMAN (Kyoto Kagaku, Japan) chest phantom were radiographed 20 times by X-ray machine (Shimadzu, Japan) with 110 kVp, 3.2 mAs, FOV set at 40×40 cm², SID at 100 cm, All data were calculated by Excel software with descriptive analysis. The results depicted the average of primary beam of X-ray to the phantom was 1545.10 μԌy, and that of surround radiation dose was 25.11 μԌy, the average of scatter radiation at cathode side was197.15 μԌy, and that of 81.07 μԌy at anode one, background radiation dose was detected of 2.98 μԌy. The study suggests that the radiation dose other than primary bean was lower and obviously directional. It shows the heel effect plays an important role of radiation distribution at exposure. The study also receives the highest average scatter radiation dose at the point of 50cm away from examination table, it gradually decreased of center of primary beam were also observed.