No / 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.

Accurate measures of both clinical image quality and patient radiation risk are needed for successful optimisation of medical imaging with ionising radiation. Optimisation in diagnostic radiology means finding the image acquisition technique that maximises the perceived information content and minimises the radiation risk or keeps it at a reasonably low level. The assessment of image quality depends on the diagnostic task and may in addition to system and quantum noise also be hampered by overlying projected anatomy. The main objective of this thesis is to develop methods for assessment of image quality in simulations of projection radiography. In this thesis, image quality is quantified by modelling the whole x‐ray imaging system including the x‐ray tube, patient, anti‐scatter device, image detector and the observer. This is accomplished by using Monte Carlo (MC) simulation methods that allow simultaneous estimates of measures of image quality and patient dose. Measures of image quality include the signal‐to‐noise‐ratio, SNR, of pathologic lesions and radiation risk is estimated by using organ doses to calculate the effective dose. Based on high‐resolution anthropomorphic phantoms, synthetic radiographs were calculated and used for assessing image quality with model‐observers (Laguerre‐Gauss (LG) Hotelling observer) that mimic real, human observers. Breast and particularly chest imaging were selected as study cases as these are particularly challenging for the radiologists. In chest imaging the optimal tube voltage in detecting lung lesions was investigated in terms of their SNR and the contrast of the lesions relative to the ribs. It was found that the choice of tube voltage depends on whether SNR of the lesion or the interfering projected anatomy (i.e. the ribs) is most important for detection. The Laguerre‐Gauss (LG) Hotelling observer is influenced by the projected anatomical background and includes this into its figure‐of‐merit, SNRhot,LG. The LG‐observer was found to be a better model of the radiologist than the ideal observer that only includes the quantum noise in its analysis. The measures of image quality derived from our model are found to correlate relatively well with the radiologist’s assessment of image quality. Therefore MC simulations can be a valuable and an efficient tool in the search for dose‐efficient imaging systems and image acquisition schemes.

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 FC / Introduction: 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

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 FC / Introduction: 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

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.

In einer initialen Studie verglichen wir das XQi Revolution, welches auf indirektem CsI (Cäsium Iodit) /a: Si (amorphes Silizium) basiert mit einem direkten Digitalröntgengerät a: SE (amorphes Selen) an einem CDRAD-Phantom bei vier unterschiedlichen Eintrittsdosen und an einem TRG-Phantom bei zwei unterschiedlichen Eintrittsdosen. Mittels des berechneten Bildqualitätsfaktors des CDRAD-Phantoms konnten wir zeigen, daß das indirekte im Vergleich zum direkten System bei niedrigeren Dosen eine bessere Detailerkennungsrate aufweist. Ein positiver Trend läßt sich auch beim TRG-Phantom darstellen. In einer weiteren Studie untersuchten wir anhand von Patientenbildern die Bildqualität des Dual Energy Systems bei zwei unterschiedlichen Dosisniveaus, der Standarddosis sowie einer doppelten Dosis, was einem Speed-Äquivalent von 400/1000 bzw. 200/500 entspricht. Bei hoher Dosis konnten wir eine signifikante Reduktion des Rauschens im Knochen- und Weichteilbild feststellen, gleichzeitig nahmen die Störungen durch Bewegungsartefakte signifikant zu. Im Anschluß verglichen wir die Erkennbarkeit verkalkter Lungenpathologien im Standard P/A Bild mit zusätzlichem Einsatz von Dual Energy. Als Goldstandard erfolgte der sichere Nachweis der Pathologien im CT. Bei zusätzlichem Einsatz von Dual Energy konnten wir eine signifikante Steigerung der Sensitivität erkennen. Dieses Ergebnis wurde durch den Qualitätsfaktor, der die Bildeigenschaften kumulativ beschreibt, bestätigt. Weiterhin untersuchten wir analog die Erkennbarkeit von nichtverkalkten Lungenrundherden. Auch bei diesen Pathologien ließ sich ein positiver Trend der Sensitivität und Spezifität bei zusätzlichem Einsatz von Dual Energy erkennen. Zusätzlich stieg die durchschnittliche Entscheidungssicherheit der Gutachter signifikant an. Damit bietet die Dual Energy Subtraktionstechnik eine wertvolle Ergänzung in der Diagnostik verkalkter und nichtverkalkter Lungenpathologien eine wertvolle Ergänzung zum Standardröntgen. / First study assess and quantify the image quality at two dose levels for an amorphous Silicon (a:Si) Cesium Iodide (CsI) flat panel system compared with a direct amorphous Selenium (a:Se) digital radiography system. Image quality of a:Si flat panel digital radiography proved to be superior to a:Se drum digital radiography using low-dose settings. Second study assess the image quality of subtracted soft tissue and bone images of a CsIdetector-based dual-energy system for chest radiography at varying dose levels. Radiation dose did not significantly influence the perception of dual-energy image quality. Next study assess the value of dual-energy chest radiography obtained using a cesium iodide flat-panel detector in addition to standard posteroanterior chest radiography for the detection of calcified chest abnormalities. When dual-energy images were added, sensitivity increased significantly. Brunner and Langer’s test revealed a highly significant difference between posteroanterior chest radiography and dual-energy imaging in the detection of calcified chest abnormalities. Dual-energy images added to standard posteroanterior chest radiographs significantly improve the detection of calcified chest lesions. Last study compare the sensitivity and specificity of digital chest radiography alone with digital chest radiography combined with dual-energy chest radiography in the detection of small non-calcified pulmonary nodules. Standard and dual-energy radiographs were obtained with a flat-panel digital chest system. The increase of nodule detection overall as well as for different size categories was significant. The increase of the confidence level rating was also significant. Dual energy added to standard posteroanterior chest radiography significantly improves the sensitivity, specificity, and confidence in detection of small non-calcified pulmonary nodules. Dual-energy subtraction has the potential to become a future routine application in chest radiography.