Quantitative chest X-ray radiomics for therapy response monitoring in patients with pulmonary tuberculosis

DATA AVAILABILITY STATEMENT : Data are available on request from the corresponding author.Tuberculosis (TB) remains the second leading cause of death globally from a single infectious agent, and there is a critical need to develop improved imaging biomarkers and aid rapid assessments of responses to therapy. We aimed to utilize radiomics, a rapidly developing image analysis tool, to develop a scoring system for this purpose. A chest X-ray radiomics score (RadScore) was developed by implementing a unique segmentation method, followed by feature extraction and parameter map construction. Signature parameter maps that showed a high correlation to lung pathology were consolidated into four frequency bins to obtain the RadScore. A clinical score (TBscore) and a radiological score (RLscore) were also developed based on existing scoring algorithms. The correlation between the change in the three scores, calculated from serial X-rays taken while patients received TB therapy, was evaluated using Spearman’s correlation. Poor correlations were observed between the changes in the TBscore and the RLscore (0.09 (p-value = 0.36)) and the TBscore and the RadScore (0.02 (p-value = 0.86)). The changes in the RLscore and the RadScore had a much stronger correlation of 0.22, which is statistically significant (p-value = 0.02). This shows that the developed RadScore has the potential to be a quantitative monitoring tool for responses to therapy.FUNDING : The APC was funded by the Department of Nuclear Medicine, University of Pretoria, South Africa.https://www.mdpi.com/journal/diagnosticsam2024Nuclear MedicineStatisticsSDG-03:Good heatlh and well-bein

Singularities in foreign tourist arrivals and tax collection in Quintana Roo, Mexico

Más allá de análisis enfocados a cifras absolutas o porcentuales en cambios en llegadas de turistas, para algunos de gran importancia y para otros no, acontecidos en el transcurso del tiempo, son la razón para el objetivo de este trabajo, desarrollando mediciones para identificar la presencia de cambios que puedan ser considerados como estadísticamente significativos. Los resultados muestran que, lejos de esperarse en disminuciones causadas por el huracán Wilma o la contingencia por H1N1, se presentan aumentos de llegadas, todas, en el año 2016, pero sin incidir en el impuesto al hospedaje.Beyond analysis focused on absolute figures or percentage on changes in tourist arrivals, for some of great importance and for others not, occurred in the course of time, are the reason for the objective of this work, developing measurements to identify the presence of changes that can be considered as statistically significant. The results show that, far from the expected, decreases caused by Hurricane Wilma or the H1N1 contingency, they showed more arrivals, all of them, in 2016 but without affecting the lodging tax

Robust image steganography method suited for prining = Robustna steganografska metoda prilagođena procesu tiska

U ovoj doktorskoj dizertaciji prezentirana je robustna steganografska metoda razvijena i prilagođena za tisak. Osnovni cilj metode je pružanje zaštite od krivotvorenja ambalaže. Zaštita ambalaže postiže se umetanjem više bitova informacije u sliku pri enkoderu, a potom maskiranjem informacije kako bi ona bila nevidljiva ljudskom oku. Informacija se pri dekoderu detektira pomoću infracrvene kamere. Preliminarna istraživanja pokazala su da u relevantnoj literaturi nedostaje metoda razvijenih za domenu tiska. Razlog za takav nedostatak jest činjenica da razvijanje steganografskih metoda za tisak zahtjeva veću količinu resursa i materijala, u odnosu na razvijanje sličnih domena za digitalnu domenu. Također, metode za tisak često zahtijevaju višu razinu kompleksnosti, budući da se tijekom reprodukcije pojavljuju razni oblici procesiranja koji mogu kompromitirati informaciju u slici [1]. Da bi se sačuvala skrivena informacija, metoda mora biti otporna na procesiranje koje se događa tijekom reprodukcije. Kako bi se postigla visoka razina otpornosti, informacija se može umetnuti unutar frekvencijske domene slike [2], [3]. Frekvencijskoj domeni slike možemo pristupiti pomoću matematičkih transformacija. Najčešće se koriste diskretna kosinusna transformacija (DCT), diskretna wavelet transformacija (DWT) i diskretna Fourierova transformacija (DFT) [2], [4]. Korištenje svake od navedenih transformacija ima određene prednosti i nedostatke, ovisno o kontekstu razvijanja metode [5]. Za metode prilagođene procesu tiska, diskretna Fourierova transformacija je optimalan odabir, budući da metode bazirane na DFT-u pružaju otpornost na geometrijske transformacije koje se događaju tijekom reprodukcije [5], [6]. U ovom istraživanju korištene su slike u cmyk prostoru boja. Svaka slika najprije je podijeljena u blokove, a umetanje informacije vrši se za svaki blok pojedinačno. Pomoću DFT-a, ???? kanal slikovnog bloka se transformira u frekvencijsku domenu, gdje se vrši umetanje informacije. Akromatska zamjena koristi se za maskiranje vidljivih artefakata nastalih prilikom umetanja informacije. Primjeri uspješnog korištenja akromatske zamjene za maskiranje artefakata mogu se pronaći u [7] i [8]. Nakon umetanja informacije u svaki slikovni blok, blokovi se ponovno spajaju u jednu, jedinstvenu sliku. Akromatska zamjena tada mijenja vrijednosti c, m i y kanala slike, dok kanal k, u kojemu se nalazi umetnuta informacija, ostaje nepromijenjen. Time nakon maskiranja akromatskom zamjenom označena slika posjeduje ista vizualna svojstva kao i slika prije označavanja. U eksperimentalnom dijelu rada koristi se 1000 slika u cmyk prostoru boja. U digitalnom okruženju provedeno je istraživanje otpornosti metode na slikovne napade specifične za reprodukcijski proces - skaliranje, blur, šum, rotaciju i kompresiju. Također, provedeno je istraživanje otpornosti metode na reprodukcijski proces, koristeći tiskane uzorke. Objektivna metrika bit error rate (BER) korištena je za evaluaciju. Mogućnost optimizacije metode testirala se procesiranjem slike (unsharp filter) i korištenjem error correction kodova (ECC). Provedeno je istraživanje kvalitete slike nakon umetanja informacije. Za evaluaciju su korištene objektivne metrike peak signal to noise ratio (PSNR) i structural similarity index measure (SSIM). PSNR i SSIM su tzv. full-reference metrike. Drugim riječima, potrebne su i neoznačena i označena slika istovremeno, kako bi se mogla utvrditi razina sličnosti između slika [9], [10]. Subjektivna analiza provedena je na 36 ispitanika, koristeći ukupno 144 uzorka slika. Ispitanici su ocijenjivali vidljivost artefakata na skali od nula (nevidljivo) do tri (vrlo vidljivo). Rezultati pokazuju da metoda posjeduje visoku razinu otpornosti na reprodukcijski proces. Također, metoda se uistinu optimizirala korištenjem unsharp filtera i ECC-a. Kvaliteta slike ostaje visoka bez obzira na umetanje informacije, što su potvrdili rezultati eksperimenata s objektivnim metrikama i subjektivna analiza

Quantification of pulmonary tuberculosis characteristics from digital chest x-rays using radiomics

Thesis (PhD (Nuclear Medical Sciences))--University of Pretoria, 2023.Pulmonary tuberculosis (PTB) is internationally one of the leading causes of death from a single infectious agent, and South Africa remains in the top 8 countries globally with the highest number of new infections. A chest x-ray (CXR) is still the most common radiological imaging procedure for PTB screening, diagnosis and monitoring, but it cannot be used as a standalone diagnostic tool due to the subjectivity associated with reporting. This can be addressed by quantifying digital CXR with tools such as radiomic feature extraction. In this thesis a unique sliding window segmentation method was developed to eliminate the difficult and time-consuming task of accurate PTB disease segmentation from planar images. It was applied as a secondary segmentation, superimposed on a primary automatic lung segmentation, that divided the entire lung region into uniform windows that overlapped while sliding over the CXR in both image dimensions. When radiomic features were extracted from each sliding window, it allowed the distribution of the features across the lung region to be evaluated. Three different outcomes were achieved when radiomic feature extraction was applied to chest x-rays using the sliding window segmentation. Firstly a model was developed that can automatically differentiate normal CXR from CXR with PTB cavities, which could improve the accuracy of CXR reporting currently regaining prominence as a high-volume screening tool. Secondly, signature parameter maps that showed a strong correlation to the lung pathology were constructed. This might be valuable as a quantitative supplementary indicator in the management of PTB disease and further increase the acceptance of CXR as a tool for assessing the TB response in medical research and clinical practice. Finally, a radiomics score was constructed that was able to quantify the change in the disease characteristics as seen from digital CXR of patients diagnosed with PTB. This radiomic score analysis of serial x-rays taken while patients receive TB therapy has the potential to be a quantitative monitoring tool of response to therapy. Radiomics was therefore successfully applied in this study to quantify the characteristics of PTB from chest x-rays.Nuclear MedicinePhD (Nuclear Medical Sciences)UnrestrictedFaculty of Health SciencesSDG-03: Good health and well-bein

Análisis de la resistencia a la compresión de concretos y cementos hidráulicos costarricenses

Proyecto de Graduación (Licenciatura en Ingeniería en Construcción) Instituto Tecnológico de Costa Rica, Escuela de Ingeniería en Construcción, 2020Los cementos hidráulicos costarricenses son adicionados o combinados, por lo que contienen materiales, como adiciones, en sustitución de un porcentaje del clínker. Cada tipo de cemento contiene adiciones en diferente proporción, por ello es importante conocer cuál es el comportamiento de los concretos según el cemento hidráulico con el cual se fabriquen. Las tecnologías de los cementos hidráulicos y las características de los componentes adicionados pueden variar a lo largo del tiempo, ello hace que sea necesario el estudio periódico del comportamiento del concreto hidráulico a nivel nacional. En este estudio se analiza la resistencia a la compresión de concretos y cementos hidráulicos, fabricados con cinco tipos de cementos nacionales, correspondientes a tres proveedores. Se fallaron cilindros de concreto y cubos de mortero a los 7, 14, 28, 133, 140 y 147 días. Los resultados obtenidos se analizaron mediante un tratamiento estadístico que incluye desde estadística descriptiva hasta pruebas de ANOVA y Tukey para conocer si existen diferencias entre tratamientos. Se demostró que existen diferencias significativas de las resistencias promedio entre concretos y cementos hidráulicos de la misma clase de resistencia. Además, se encontró que todos los concretos analizados alcanzan elevados porcentajes de resistencia hasta los 147 días, aproximadamente entre 40% y 84% más de la resistencia de diseño (f’c), según el tipo de cemento.Costa Rican hydraulic cements are blended cements, they contain additions as percentage substitution of clinker. Each cement type has additions in different proportions, due to this is important to know the concrete behavior in accordance with hydraulic cement of fabrication. Cements technologies and addition materials’ characteristics may change through time, for this reason is necessary the periodic study of concrete’s behavior in Costa Rica. In this study is analyze concrete and hydraulic cement compressive strength, made with five national cements types of three suppliers. Concrete cylinders and mortars cubes were tested at 7, 14, 28, 133, 140 and 147 days. Obtained results were analyzed with a statistic treatment including since descriptive statistic until ANOVA and Tukey tests in order to know significant differences between treatments. According to results there is evidence that exist significant differences between average strength of some concretes and hydraulic cements from the same strength class. Additionally, all analyzed concretes reach high strength percentages until 147 days, approximately between 40% and 84% more than the design strength (f’c), depending on cement type