Sustracción Radiográfica Digital de la Estructura Dentaria Removida Durante el Acceso Endodóntico En Incisivos Mandibulares / Digital Subtraction Radiography of Dental Hard Tissue Removed During Endodontic Access in Mandibular Incisors

El objetivo de este estudio fue comparar la estructura dentaria removida utilizando dos técnicas de acceso endodóntico diferentes en incisivos mandibulares. Treinta y cinco incisivos mandibulares extraídos fueron pesados individualmente con una balanza de precisión. Después de las radiografías iniciales tomadas por vestibular y proximal, los dientes fueron codificados y asignados aleatoriamente a dos grupos: acceso convencional (n = 17) o acceso incisal (n = 18). Luego se volvieron a pesar los dientes y se repitieron las radiografías. Las radiografías digitales se cargaron a un editor de imágenes (Adobe Photoshop) para la sustracción digital de las imágenes por las incidencias VP y MD. Dos observadores independientes y calibrados realizaron las mediciones de las áreas sustraídas. La concordancia inter-observador fue casi perfecta; coeficiente de correlación intraclase igual a 0,94 y 0,98 para las incidencias MD y VP, respectivamente. La prueba de Mann-Whitney encontró diferencias estadísticamente significativas entre los tipos de acc esos en cuanto a la diferencia mediana de los pesos (p = 0,0073) y el área VL (p = 0.0023). También encontró una diferencia estadísticamente significativa entre los tipos de acceso en cuanto al área MD (Prueba t de Welch, p < 0,001). La diferencia de peso fue menor para el acceso incisal que para el acceso convencional. El acceso incisal removió menos tejido dentario que el acceso convencional.

The aim of this study was to compare the area of tooth structure removed during two different endodontic access techniques in lower incisors. Thirty-two extracted lower incisors were weighed individually on a precision scale. After initial digital radiographs were taken from buccal and proximal, the teeth were coded and randomly assigned to two different groups: conventional access and incisal access. Once this stage was completed, each tooth was weighed again and 2 postoperative radiographs was taken again, buccal and proximal. Using an image processing software and digital subtraction technique, 2 independent and calibrated evaluators measured difference in tooth structure after access procedures. Interobserver agreement was almost perfect: intraclass correlation coefficient equal to 0,94 and 0,98 for proximal and buccal incidences, respectively. The Mann-Whitney test found statistically significant differences between the types of accesses in terms of weight difference (p = 0.0073) and area VL (p = 0.0023). Additionally, a statistically significant difference between the types of access in the MD area (Welch's t test, p <0.005) was observed. The difference in weight was less for incisal access than for conventional access with a statistically significant difference, in terms of MD and VL area, incisal access and areas of smaller size than conventional access.

Video analysis and 3d detection simulation of jump shot precision for basketball players / Análise de vídeo e simulação de detecção 3d da precisão do arremesso de jogadores de basquete / Análisis de video y simulación tridimensional de la precisión de lanzamiento de los jugadores de baloncesto

ABSTRACT With the rapid development and application of computer technology, the application of computer science knowledge in basketball is also more and more extensive. Based on genetic algorithm and the background subtraction method, video analysis and 3D detection simulation model of shot jump action precision were constructed in this study. According to the genetic algorithm search method, jump shot precision was analyzed, and the problems encountered in the actual shooting process of basketball players were studied and solved. The results show that this study is necessary and feasible.

RESUMO Com o rápido desenvolvimento e aplicação da tecnologia da computação, a aplicação do conhecimento da ciência da computação no basquete também vem crescendo cada vez mais. Com base no algoritmo genético e no método da subtração de fundo, construiu-se um modelo de análise de vídeo e simulação de detecção 3D para a precisão de arremesso. De acordo com o método de busca do algoritmo genético, analisou-se a precisão do arremesso, e os problemas encontrados no processo de arremesso dos jogadores de basquete foram estudados e resolvidos. Os resultados mostram que este estudo é necessário e viável.

RESUMEN Con el rápido desarrollo y aplicación de la tecnología de la computación, la aplicación del conocimiento de la ciencia de la computación en el baloncesto también viene creciendo cada vez más. Basándose en el algoritmo genético y en el método de la sustracción de fondo, se construyó un modelo de análisis de video y simulación de detección 3D para la precisión de lanzamiento. De acuerdo con el método de búsqueda del algoritmo genético, se analizó la precisión del lanzamiento, y los problemas encontrados en el proceso de lanzamiento de los jugadores de baloncesto fueron estudiados y resueltos. Los resultados muestran que este estudio es necesario y viable.

High-resolution Micro-CT Myelography to Assess Spinal Subarachnoid Space Changes After Spinal Cord Injury in Rats.

BACKGROUND AND PURPOSE: The spinal subarachnoid space (SSAS) is vital for neurologic function. Although SSAS alterations are known to occur after spinal cord injury (SCI), there is a lack of high-resolution imaging studies of the SSAS after SCI in rodents. Therefore, the aim here was to assess changes in the SSAS of rats subjected to graded SCI, using high-resolution micro-CT myelography. METHODS: Long-Evans adult rats were subjected to mild or severe spinal cord contusion at T9. Imaging studies of SSAS features were carried out in injured rats at acute (day 1) and subacute (day 15) stages postinjury, as well as in control rats, using high-resolution micro-CT myelography with a contrast-enhanced digital subtraction protocol. We studied a total of 33 rats randomly allocated into five experimental groups. Micro-CT myelograms were assessed by expert observers using both qualitative and quantitative criteria. RESULTS: Qualitative and quantitative analyses showed that SCI induces changes in the SSAS that vary as a function of both injury severity and time elapsed after injury. SSAS blockage was the main alteration detected. Moreover, the method used here allowed fine details to be observed in small animals, such as variations in the preferential pathways for contrast medium flow, neuroimaging nerve root enhancement, and leakage of contrast medium due to tearing of the dural sac. CONCLUSION: Micro-CT myelography provides high-resolution images of changes in the SSAS after SCI in rats and is a useful tool for further experimental studies involving rat SCI in vivo.

Micro-CT myelography using contrast-enhanced digital subtraction: feasibility and initial results in healthy rats.

PURPOSE: The spinal subarachnoid space (SSAS) is vital for neural performance. Although models of spinal diseases and trauma are used frequently, no methods exist to obtain high-resolution myelograms in rodents. Thereby, our aim was to explore the feasibility of obtaining high-resolution micro-CT myelograms of rats by contrast-enhanced dual-energy (DE) and single-energy (SE) digital subtraction. METHODS: Micro-CT contrast-enhanced DE and SE imaging protocols were implemented with live adult rats (total of 18 animals). For each protocol, contrast agents based on iodine (Iomeron® 400 and Fenestra® VC) and gold nanoparticles (AuroVist™ 15 nm) were tested. For DE, images at low- and high-energy settings were acquired after contrast injection; for SE, one image was acquired before and the other after contrast injection. Post-processing consisted of region of interest selection, image registration, weighted subtraction, and longitudinal alignment. RESULTS: High-resolution myelograms were obtained with contrast-enhanced digital subtraction protocols. After qualitative and quantitative (contrast-to-noise ratio) analyses, we found that the SE acquisition protocol with Iomeron® 400 provides the best images. 3D contour renderings allowed visualization of SSAS and identification of some anatomical structures within it. CONCLUSION: This in vivo study shows the potential of SE contrast-enhanced myelography for imaging SSAS in rat. This approach yields high-resolution 3D images without interference from adjacent anatomical structures, providing an innovative tool for further assessment of studies involving rat SSAS.

A posteriori registration and subtraction of periapical radiographs for the evaluation of external apical root resorption after orthodontic treatment.

PURPOSE: This study employed a posteriori registration and subtraction of radiographic images to quantify the apical root resorption in maxillary permanent central incisors after orthodontic treatment, and assessed whether the external apical root resorption (EARR) was related to a range of parameters involved in the treatment. MATERIALS AND METHODS: A sample of 79 patients (mean age, 13.5±2.2 years) with no history of trauma or endodontic treatment of the maxillary permanent central incisors was selected. Periapical radiographs taken before and after orthodontic treatment were digitized and imported to the Regeemy software. Based on an analysis of the posttreatment radiographs, the length of the incisors was measured using Image J software. The mean EARR was described in pixels and relative root resorption (%). The patient's age and gender, tooth extraction, use of elastics, and treatment duration were evaluated to identify possible correlations with EARR. RESULTS: The mean EARR observed was 15.44±12.1 pixels (5.1% resorption). No differences in the mean EARR were observed according to patient characteristics (gender, age) or treatment parameters (use of elastics, treatment duration). The only parameter that influenced the mean EARR of a patient was the need for tooth extraction. CONCLUSION: A posteriori registration and subtraction of periapical radiographs was a suitable method to quantify EARR after orthodontic treatment, and the need for tooth extraction increased the extent of root resorption after orthodontic treatment.

Comparison of changes in dental and bone radiographic densities in the presence of different soft-tissue simulators using pixel intensity and digital subtraction analyses.

OBJECTIVES: To evaluate the influence of soft-tissue simulation materials on dental and bone tissue radiographic densities using pixel intensity (PI) and digital subtraction radiography (DSR) analyses. METHODS: 15 dry human mandibles were divided into halves. Each half was radiographed using a charge-coupled device sensor without a soft-tissue simulation material (Wm) and with 5 types of materials: acrylic (Ac), wax (Wx), water (Wt), wood (Wd) and frozen bovine tissue (Bt). Three thicknesses were tested for each material: 10 mm, 15 mm and 20 mm. The material was positioned in front of the mandible and the sensor parallel to the molar region. The radiation beam was perpendicular to the sensor at 30 cm focal spot-to-object distance. The digital images of the bone and dental tissue were captured for PI analyses. The subtracted images were marked with 14 landmark magnifications, and 2 areas of analyses were defined, forming the regions of interest. Shapiro-Wilk and Kruskal-Wallis tests followed by Dunn's post-test were used (p < 0.05). RESULTS: DSR showed that both the material type and the thickness tested influenced the gain of density in bone tissue (p < 0.05). PI analyses of the bone region did not show these differences, except for the lower density observed in the image without soft-tissue simulation material. In the dental region, both DSR and PI showed that soft-tissue simulators did not influence the density in these regions. CONCLUSIONS: This study showed that the materials evaluated and their thicknesses significantly influenced the density-level gain in alveolar bone. In dental tissues, there was no density-level gain with any soft-tissue material tested.

Comparação de diferentes métodos de registro (a priori e a posteriori) na subtraçÆo radiográfica digital (SRD) para avaliação da produção de ruídos estruturais / Comparison of different recording methods (a priori and a posteriori) in the digital radiographic subtraction (DRS) to evaluate the production of structural noise

Objetivo: A Subtração Radiográfica Digital (SRD) é uma técnica utilizada para comparar duas radiografias de um mesmo objeto, realizadas em diferentes momentos, para demonstrar a existência de diferenças entre elas. Contudo, a reprodutibilidade da geometria de relação entre objeto, filme e fonte de raios X é indispensável para evitar a formação de ruídos estruturais. O objetivo deste trabalho foi comparar a aplicação de diferentes métodos de registros (a priori e a posteriori), em diferentes tempos de exposiçao (0,2 e 0,4 segundos), na produçÆo de ruído estrutural em imagens subtraídas. Método: dez mandíbulas foram radiografadas em duas situaçães: com uso de posicionadores convencionais sem registro e com registro a priori, sendo que ambos os métodos foram reproduzidos após 15 dias. O registro a posteriori foi realizado por meio do programa Regeemy© 0.2.43, e a subtraçÆo no programa Image Tool© 3.0. O ruído estrutural foi quantificado pelo programa Adobe Photoshop©7.0, que fornece valores de desvio padrÆo dos níveis de cinza na regiÆo de interesse (ROI). Esses valores foram submetidos à análise estatística ANOVA e teste Tukey a 5% de significância. Resultados: no tempo de exposiçÆo 0,4 s, os grupos obtiveram valores menores de desvio padrÆo em relaçÆo ao tempo de 0,2 s. Os grupos com registro a posteriori e a priori associados tiveram os menores valores de desvio padrÆo, seguidos pelos grupos com registro a posteriori. ConclusÆo: nas condiçães estudadas, o tempo de 0,4 s foi o mais adequado e a utilizaçÆo do registro a posteriori foi essencial na formaçÆo de imagens subtraídas com baixo ruído estrutural...

Objective: The Digital Radiographic Subtraction (DRS) is a technique used for comparing two radiographs of the same subject taken at different moments to demonstrate the differences between them. However, reproducibility of the geometry of relation among object, film and x-ray source is mandatory to avoid structural noise formation. The aim of this study was to compare the application of different recording methods (a priori and a posteriori) at different exposure times (0.2 and 0.4 s) on the production of structural noises in subtracted images. Method: Radiographs of 10 mandibles were taken using conventional film holders without and with a priori record, and then both methods were reproduced 15 days later. The a posteriori record was made using the Regeemy© 0.2.43 software and the subtraction was performed with Image Tool© 3.0. Results: with the 0.4 s exposure time, the groups presented lower standard deviation values compared with the 0.2 s exposure. The groups with a posteriori and a priori records had the lowest standard deviation values, followed by the groups with a posteriori record. Conclusion: Under the tested conditions, the 0.4 s exposure time was more appropriate and the use of a posteriori record was essential to obtain subtracted images with low structural noise...

Comparação entre subtração radiográfica digital e radiografia digital direta na detecção de reabsorções radiculares / Comparison between radiographic digital subtraction and direct digital radiography in the detection of root resorption

A reabsorção severa da raiz diagnosticada tardiamente pode acarretar a perda dentária. Devido ao fato de a técnica de subtração radiográfica digital ser um importante recurso para detecção precoce de alterações minerais, este estudo propôs avaliar a eficiência no diagnóstico precoce da reabsorção radicular externa simulada nas regiões apical e lingual, pelas técnicas de subtração radiográfica digital e radiografia digital. Foram utilizados 14 dentes incisivos de mandíbulas humanas maceradas com reabsorções de diferentes dimensões, simuladas nas regiões apical e lingual, e radiografados com variação de ângulos de projeção. As radiografias foram subtraídas pelo programa Regeemy®, e para avaliação de desempenho dos métodos de diagnóstico, pares de radiografias periapicais e imagens subtraídas foram apresentadas a dois radiologistas. De acordo com os resultados, não foram observadas diferenças estatisticamente significantes entre os métodos na detecção de reabsorções linguais, independentemente do tamanho da lesão. Também não houve diversidade entre os métodos na detecção de reabsorções apicais, com exceção do examinador dois quanto às variações angular vertical e horizontal de 10º, utilizando o maior nível de desgaste, que apresentou a radiografia digital como método superior na avaliação em relação à subtração radiográfica. Também foi observado que o aumento do nível de desgaste permitiu melhor avaliação nas regiões de reabsorções apicais e linguais, e a menor variação dos ângulos verticais e horizontais nas detecções de reabsorções apicais e linguais permitiu uma melhor avaliação da imagem, principalmente no menor nível de desgaste.

The delay on diagnose severe root resorption can lead to tooth loss. Due to the fact that digital subtraction radiography is an important resource to detect initial mineral changes, this study aimed at evaluating the effectiveness of the digital subtraction radiography and digital radiography in early diagnosis of the simulated apical and lingual external root resorption. Fourteen human lower incisors, submitted to simulated apical and lingual resorption cavities of different sizes, imaged with different angle projection variations were included in this study. The images were subtracted by the Regeemy® program, and receiver operating characteristic analysis was used to evaluate the diagnostic performance for each imaging system, and the diagnostic accuracy of both diagnosis methods for detecting lesions was conducted by the assessment of the pairs of radiography (digital and subtracted) by two radiologists. According to the results, there were no statistically significant differences between the methods in detecting lingual resorption, independently of the lesion dimension. There was also no difference on the apical resorption detection, except by the viewer two as to 10º horizontal and vertical angles, who related that on the larger cavity, the digital radiography was more reliable than the subtraction radiography. It was also further noticed that the deeper the cavity size, the better the apical and lingual resorption detection; and the radiography taken of the apical and lingual resorption, with the smaller vertical and horizontal angles variation ensured a better assessment of the image, mainly on the shallower cavity size.

Influência dos simuladores de tecidos moles na densidade óssea e dentária por meio de duas análises radiográficas: subtração digital e intensidade de pixel / Influence of soft tissue materials in bone and tooth density through two radiographic analyses: digital subtraction and pixel intensity

Esse estudo teve como objetivo avaliar a influência dos simuladores de tecidos moles na imagem radiográfica digital, da região óssea e dental, pela subtração radiográfica e análise da intensidade de pixel. 30 mandíbulas humanas com 2 dentes posteriores foram selecionadas. Um dispositivo para o posicionamento do cilindro de raios X, mandíbula e sensor CCD eHD Visualix Gendex foi confeccionado. As mandíbulas foram posicionadas no dispositivo e 5 materiais simuladores de tecido mole (Acrílico, Cera, Água, Madeira e Tecido bovino) nas espessuras de 10mm, 15mm e 20mm foram posicionados anteriormente a mandíbula, em seqüência para a realização das tomadas radiográficas com 65 kV, 7mA, distância foco-sensor de 30 cm, e 0,08s. As imagens foram exportadas em 8 e 16 bits para análise. A subtração foi realizada com o programa X-Poseit usando a imagem sem material como referência da imagem com o material, em duas regiões, osso e estrutura dental. A área de ganho de densidade óssea e dental foi avaliada quanto à influência dos materiais e espessuras. A análise por intensidade de pixel foi realizada tanto no osso quanto na estrutura dental, numa área de 100x100pixels, com o programa ImageJ. Foi adotado o nível de significância de 0,05. Os resultados da subtração radiográfica digital e intensidade de pixel mostraram que tanto os simuladores testados influenciaram o ganho de densidade na região do osso. Entretanto, não foi encontrada diferenças entre os materiais e espessuras testados. Na região dental, tanto a analise por subtração quanto a por intensidade de pixel mostraram que os simuladores de tecido mole não influenciaram a densidade dessas regiões. A avaliação da profundidade de bit mostrou que não houve diferença entre os resultados. Podemos concluir que os simuladores de tecido mole influenciaram na densidade óssea e dental.

This study aimed to evaluate the effect of soft tissue simulators in digital radiographic image, of tooth and bone, by digital subtraction radiography and pixel intensity analysis. 30 human mandibles with two posterior teeth were selected. A device for positioning the cylinder X-ray, jaw and EHD Visualix Gendex CCD sensor was manufactured. The jaws were positioned on the device and 5 soft tissue simulators materials (acrylic, wax, water, wood, and bovine tissue) in thicknesses of 10mm, 15mm and 20mm, were positioned in front of the jaw line, in sequence to perform the X-ray expositions at 65 kV, 7mA, plate-focus distance of 30 cm and the exposure time of 0.08 s. The images were exported in 8 and 16 bit for analysis. The subtraction was performed with the X-Poseit image without using the image as a reference material with the material in two regions, bone and tooth structure. The gain area in bone and tooth density was assessed and the difference between material and thickness were evaluated. The pixel intensity analysis was performed both in bone and tooth structure in an area of 100x100pixels with ImageJ. Significance level of 0,05 was adopted. The results of digital subtraction radiography showed that both the material and the thickness tested didn’t influence the gain of density in bone. Pixel intensity analisys in bone region didn’t show these differences, except for lower density observed in the 14 image without material comparing with the materials tested. In the dental region, both subtraction and pixel intensity showed that soft tissue simulators influence the density of these regions. However there was no difference between the materials and thicknesses tested. The evaluation of the bit depth, showed no difference between the results. We can conclude that soft tissue materials influence bone and dental density.