Histological artifacts associated with laser and electroscalpel gingivectomy: Case series / Artefactos histológicos asociados a gingivectomía con láser y electrobisturí: serie de casos

Introduction. Over time, efforts have been invested in the design of new instruments that overcome the disadvantages of the gold standard instrument in surgery, the scalpel. As a result, electronic equipment has emerged such as the electric scalpel and laser devices. The available evidence on these instruments suggests that the tissue response is related to each instrument's physical and biological cutting principles. Objective. To compare the histological changes in gingiva samples associated with surgical cutting performed with a 940 nm diode laser, a 2780 nm erbium, chromium: yttriumscandium-gallium-garnet (Er,Cr:YSGG) laser, and an electric scalpel, by presenting a series of cases. Case presentation. We present three cases of healthy patients undergoing cosmetic surgery. The clinical examination revealed exposure of a keratinized gingiva band greater than 4 mm, normal color and texture in gingival tissue, with a firm consistency and no bleeding on periodontal probing. Gingivectomy was indicated with the following protocols: Diode laser of 940 nm at 1 W, in continuous mode; Er,Cr:YSGG laser of 2780 nm at 2.5 W, 75 Hz, H mode, air 20, water 40, gold tip MT4); and electric scalpel in cutting mode at power level four. Gingival tissue samples were taken and stored in 10% formaldehyde for histological analysis. Conclusion. All the evaluated cutting instruments generated histological changes produced by the thermal effect, the main ones being collagen coagulation and carbonization. The depth of thermal damage caused by the 2780 nm Er,Cr:YSGG laser was much lesser than that induced by the electric scalpel and the 940 nm diode laser.

Introducción. Históricamente se ha invertido esfuerzo en el diseño de nuevos instrumentos que superen las desventajas del estándar de referencia en cirugía, el bisturí. Como consecuencia de esto, han surgido equipos electrónicos como el electrobisturí y los diferentes dispositivos de tecnología láser. La información disponible sobre estos instrumentos sugiere que la respuesta del tejido intervenido está influenciada por los principios físicos y biológicos de corte del instrumento. Objetivo. Comparar los cambios histológicos en muestras de encía asociados al corte quirúrgico realizado con láser de diodo de 940 nm, láser de erbio, cromo: itrio-escandio-galio-granate (Er,Cr:YSGG) (2780nm) y electrobisturí mediante una presentación de serie de casos. Presentación de los casos. Se presentan tres casos de pacientes sanos sometidos a cirugía estética. El examen clínico reveló la exposición de una banda gingival queratinizada mayor de 4 mm, tejido gingival de color y textura normales, de consistencia firme y sin sangrado al sondaje periodontal. Se indicó gingivectomía con los siguientes protocolos: láser de diodo de 940 nm a 1 W, en modo continuo; láser de Er,Cr:YSGG de 2780 nm a 2,5 W, 75 Hz, modo H, aire 20, agua 40, punta de oro MT4; y bisturí eléctrico en modo de corte, a nivel de potencia cuatro. Se tomaron muestras de tejido gingival y se almacenaron en formaldehído al 10 % para su análisis histológico. Conclusión. Los tres instrumentos de corte generaron cambios histológicos producidos por el efecto térmico; los principales fueron coagulación del colágeno y carbonización. La profundización del daño térmico causada por el láser de Er,Cr:YSGG de 2780 nm fue mucho menor que la generada por el electrobisturí y por el láser de diodo de 940 nm.

Corrección del artefacto producido en imágenes tomográficas en equipos odontológicos / Correction of the artifact produced in tomographic images in dental equipment

Objetivo: disminuir el efecto de artefacto que generan objetos de alta densidad mediante la utilización de filtros de distintos materiales y espesores, ubicados en lugares estratégicos del tomógrafo. Material y métodos: se utilizaron filtros de aluminio y de cobre ubicados en lugares estratégicos en el equipo tomográfico. Se realizaron cortes oblicuos en piezas dentarias con restauraciones metálicas y en implantes; se midió la extensión del artefacto en ancho y alto en cada adquisición tomográfica. Resultados: se hallaron diferencias significativas respecto a la disminución de la dispersión de acuerdo con cada filtro con respecto a la no utilización de estos elementos. Conclusión: la utilización de filtros logró disminuir el efecto de artefacto en estructuras de alta densidad, obteniendo una mejor calidad de imagen para el diagnóstico, permitiendo que el software pueda reconstruir una imagen real (AU)

Objective: to diminish the artifact effect generated by high density objects by using filters of different materials and thickness, located in strategic places of the tomograph. Material and methods: aluminum and copper filters located in strategic places in the tomographic equipment were used. Oblique cuts were made on dental pieces with metal restorations and implants; the extension of the artifact in width and height was measured in each tomographic acquisition. Results: significant differences were found regarding the decrease of the dispersion according to each filter with respect to the non-use of these elements. Conclusion: the use of filters achieves to diminish the artifact effect in structures of high density, obtaining a better image quality for the diagnosis, allowing the software to reconstruct a real image (AU)

Sinogram interpolation combined with unsupervised image-to-image translation network for CT metal artifact correction / 南方医科大学学报

OBJECTIVE@#To propose a framework that combines sinogram interpolation with unsupervised image-to-image translation (UNIT) network to correct metal artifacts in CT images.@*METHODS@#The initially corrected CT image and the prior image without artifacts, which were considered as different elements in two different domains, were input into the image transformation network to obtain the corrected image. Verification experiments were carried out to assess the effectiveness of the proposed method using the simulation data, and PSNR and SSIM were calculated for quantitative evaluation of the performance of the method.@*RESULTS@#The experiment using the simulation data showed that the proposed method achieved better results for improving image quality as compared with other methods, and the corrected images preserved more details and structures. Compared with ADN algorithm, the proposed algorithm improved the PSNR and SSIM by 2.4449 and 0.0023 when the metal was small, by 5.9942 and 8.8388 for images with large metals, and by 8.8388 and 0.0130 when both small and large metals were present, respectively.@*CONCLUSION@#The proposed method for metal artifact correction can effectively remove metal artifacts, improve image quality, and preserve more details and structures on CT images.

Automatic removal algorithm of electrooculographic artifacts in non-invasive brain-computer interface based on independent component analysis / 生物医学工程学杂志

The non-invasive brain-computer interface (BCI) has gradually become a hot spot of current research, and it has been applied in many fields such as mental disorder detection and physiological monitoring. However, the electroencephalography (EEG) signals required by the non-invasive BCI can be easily contaminated by electrooculographic (EOG) artifacts, which seriously affects the analysis of EEG signals. Therefore, this paper proposed an improved independent component analysis method combined with a frequency filter, which automatically recognizes artifact components based on the correlation coefficient and kurtosis dual threshold. In this method, the frequency difference between EOG and EEG was used to remove the EOG information in the artifact component through frequency filter, so as to retain more EEG information. The experimental results on the public datasets and our laboratory data showed that the method in this paper could effectively improve the effect of EOG artifact removal and improve the loss of EEG information, which is helpful for the promotion of non-invasive BCI.

Análise comparativa da influência de filtros de pós-processamento e da variação dos parâmetros de aquisição na quantificação de artefatos metálicos em imagens de tomografia computadorizada de feixe cônico / Comparative analysis of the influence of post-processing filters and the variation of acquisition parameters in the quantification of metallic artefacts in cone-beam computed tomography

Este estudo teve como objetivo comparar o efeito de 04 filtros de realce de imagem - Multi CDT NR1 e BAR1 - do software e-Vol DX (e-Vol DX, CDT, Brasil) e os filtros 1x e 2x do software Ondemand3D (CyberMed, Seoul, Republic of Korea), na quantificação de artefatos gerados por implantes dentários em imagens de tomografia computadorizada de feixe cônico (TCFC). Foram utilizadas imagens de TCFC de um phantom de mandíbula, adquiridas com variação do material do implante (titânio (Ti) e dióxido de zircônio (ZrO2)), região do implante (incisivo, canino, pré-molar e molar), tamanho do voxel (0,25 mm e 0,30mm) e posição do phantom no FOV (central, anterior, posterior, direita e esquerda). No software ImageJ em corte axial previamente definido, e usado como referência em cada um dos volumes estudados, em imagens com e sem a aplicação dos filtros, foi realizado a quantificação dos artefatos por um radiologista devidamente calibrado (ICC 0,97). Foram definidos grupos experimentais para as análises estatísticas das variáveis 02 a 02, sempre aliadas à variável filtro e seus efeitos na quantificação dos artefatos. Os testes de Shapiro-Wilk e de Bartlett, foram utilizados para avaliar a normalidade e homoscedasticidade. Para estudo das diferenças significativas entre os grupos foram utilizados os testes de ANOVA e Tukey (paramétricos), Kruskal-Wallis seguido de Conover-Iman (não paramétricos). Os resultados evidenciaram que o Ti apresentou menor quantificação em comparação ao ZrO2, nos 02 softwares. A menor quantificação de artefatos foi obtida no software e-Vol DX, filtro BAR 1, Ti e ZrO2. Não houve diferença significativa em relação ao tamanho do voxel para os materiais estudados (p=0,975 e p=0,901), posição do implante (p>0.05) e variações de posição no FOV (p>0.05). O Filtro Multi não apresentou diferenças significativas em relação às imagens sem filtro. Para os filtros do OnDemad3D, não houve diferença entre uso e não uso, independentemente do tamanho do voxel (p>0,05). Em conclusão o filtro BAR 1 apresentou-se como uma promissora ferramenta na redução dos artefatos oriundos de implantes dentários. (AU)

This study aimed to compare the effect of 04 image enhancement filters - Multi CDT NR1 and BAR1 - of the e-Vol DX software (e-Vol DX, CDT, Brazil) and the 1x and 2x filters of the Ondemand3D software (CyberMed, Seoul, Republic of Korea), in the quantification of artifacts generated by dental implants in cone beam computed tomography (CBCT) images. CBCT images of a mandible phantom were used, acquired with variation of the implant material (titanium (Ti) and zirconium dioxide (ZrO2)), implant region (incisor, canine, premolar and molar), voxel size (0.25 mm and 0.30 mm) and phantom position in the FOV (central, anterior, posterior, right and left). In the ImageJ software, in a previously defined axial section, and used as a reference in each of the volumes studied, in images with and without the application of filters, the quantification of the artifacts was performed by a properly calibrated radiologist (ICC 0.97). Experimental groups were defined for the statistical analysis of variables 02 to 02, always combined with the filter variable and its effects on the quantification of artifacts. The Shapiro-Wilk and Bartlett tests were used to assess normality and homoscedasticity. To study the significant differences between the groups, the ANOVA and Tukey tests (parametric), Kruskal-Wallis followed by Conover-Iman (non-parametric) were used. The results showed that Ti presented lower quantification compared to ZrO2, in the 02 softwares. The lowest quantification of artifacts was obtained using the e-Vol DX software, BAR 1, Ti and ZrO2 filters. There was no significant difference regarding voxel size for the materials studied (p=0.975 and p=0.901), implant position (p>0.05) and position variations in the FOV (p>0.05). The Multi Filter did not present significant differences in relation to the unfiltered images. For OnDemad3D filters, there was no difference between use and non-use, regardless of voxel size (p>0.05). In conclusion, the BAR 1 filter presented itself as a promising tool in the reduction of artifacts from dental implants (AU)

Multiplicidade e instabilidade ontológica nos corações não-humanos / Multiplicity and ontological instability in nonhuman hearts

Resumo O artigo reflete sobre as relações entre corpos biológicos e artefatos tecnológicos, a partir da pesquisa etnográfica sobre o desenvolvimento de tecnologias de assistência circulatória, conhecidas como corações artificiais. Para compreender as corporeidades que tais dispositivos mecânicos ajudam a produzir, buscamos aqui caracterizar dois tipos de corpos instituídos a partir de práticas médicas e biotecnologias projetadas para pacientes com insuficiência cardíaca avançada. Os corpos imunológicos, produzidos a partir dos transplantes de coração, serão contrastados aos corpos biônicos, compostos pelo arranjo com corações artificiais. Propomos que é preciso considerar que cada uma dessas tecnologias se coproduz com distintas naturezas, sustentadas em materialidades, práticas, moralidades e pressupostos específicos. A atenção dada às práticas e à materialidade permitirá destacar os diversos entrelaçamentos materiais-semióticos. Resgatar a trajetória de desenvolvimento desse campo nos permitirá explorar o imaginário a partir do qual tais intervenções emergem, assim como as transformações ocorridas, ressaltando o vínculo ao corpo-máquina tecido no âmbito biomédico.

Abstract This paper reflects on the relationship between biological bodies and technological artifacts, based on ethnographic research on the development of circulatory assist technologies, known as artificial hearts. To understand the embodiment that such mechanical devices help to produce, we aim to characterize two types of bodies enacted from medical practices and biotechnologies designed for patients with advanced heart failure. The immunological bodies, produced from heart transplantation, will be contrasted with the bionic bodies, composed of the assembly with artificial hearts. We propose that it is necessary to consider each of these technologies as co-produced with different natures, supported by specific materialities, practices, moralities and assumptions. The attention given to practices and materiality will allow to highlight the various material-semiotic intertwinings. Tracing the development trajectory of this field will allow exploring the imagination from which such interventions emerge and the transformations that have occurred, emphasizing the link to the body-machine woven in the biomedical scope.

Identifying and understanding optical coherence tomography artifacts that may be confused with glaucoma / Identificando e compreendendo os artefatos de tomografia de coerência óptica que podem ser confundidos com o glaucoma

ABSTRACT Optical coherence tomography is often used for detection of glaucoma as well as to monitor progression. This paper reviews the most common types of artifacts on the optical coherence tomography report that may be confused with glaucomatous damage. We mainly focus on anatomy-related artifacts in which the retinal layer segmentation and thickness measurements are correct. In such cases, the probability maps (also known as deviation maps) show abnormal (red and yellow) regions, which may mislead the clinician to assume disease is present. This is due to the anatomic variability of the individual, and the normative database must be taken into account.

RESUMO A tomografia de coerência óptica é frequentemente usada para detectar glaucoma, bem como para monitorar a progressão. Este artigo analisa os tipos mais comuns de artefatos no relatório de tomografia de coerência óptica que podem ser confundidos com danos glaucomatosos. Nós nos concentramos principalmente nos artefatos relacionados à anatomia em que a segmentação da camada da retina e as medidas de espessura estão corretas. Nesses casos, os mapas de probabilidade (também conhecidos como mapas de desvio) mostram regiões anormais (vermelho e amarelo), o que pode induzir o clínico em erro ao supor que a doença está presente. Isto se deve à variabilidade anatômica do indivíduo, e o banco de dados normativo deve ser levado em conta.

Low-dose helical CT projection data restoration using noise estimation / 南方医科大学学报

OBJECTIVE@#To build a helical CT projection data restoration model at random low-dose levels.@*METHODS@#We used a noise estimation module to achieve noise estimation and obtained a low-dose projection noise variance map, which was used to guide projection data recovery by the projection data restoration module. A filtering back-projection algorithm (FBP) was finally used to reconstruct the images. The 3D wavelet group residual dense network (3DWGRDN) was adopted to build the network architecture of the noise estimation and projection data restoration module using asymmetric loss and total variational regularization. For validation of the model, 1/10 and 1/15 of normal dose helical CT images were restored using the proposed model and 3 other restoration models (IRLNet, REDCNN and MWResNet), and the results were visually and quantitatively compared.@*RESULTS@#Quantitative comparisons of the restored images showed that the proposed helical CT projection data restoration model increased the structural similarity index by 5.79% to 17.46% compared with the other restoration algorithms (P < 0.05). The image quality scores of the proposed method rated by clinical radiologists ranged from 7.19% to 17.38%, significantly higher than the other restoration algorithms (P < 0.05).@*CONCLUSION@#The proposed method can effectively suppress noises and reduce artifacts in the projection data at different low-dose levels while preserving the integrity of the edges and fine details of the reconstructed CT images.

An adaptive CT metal artifact reduction algorithm that combines projection interpolation and physical correction / 南方医科大学学报

OBJECTIVE@#To propose an adaptive weighted CT metal artifact reduce algorithm that combines projection interpolation and physical correction.@*METHODS@#A normalized metal projection interpolation algorithm was used to obtain the initial corrected projection data. A metal physical correction model was then introduced to obtain the physically corrected projection data. To verify the effectiveness of the method, we conducted experiments using simulation data and clinical data. For the simulation data, the quantitative indicators PSNR and SSIM were used for evaluation, while for the clinical data, the resultant images were evaluated by imaging experts to compare the artifact-reducing performance of different methods.@*RESULTS@#For the simulation data, the proposed method improved the PSNR value by at least 0.2 dB and resulted in the highest SSIM value among the methods for comparison. The experiment with the clinical data showed that the imaging experts gave the highest scores of 3.616±0.338 (in a 5-point scale) to the images processed using the proposed method, which had significant better artifact-reducing performance than the other methods (P < 0.001).@*CONCLUSION@#The metal artifact reduction algorithm proposed herein can effectively reduce metal artifacts while preserving the tissue structure information and reducing the generation of new artifacts.

Mortality from anti-personnel mines before and during the Colombian peace process / Mortalidad secundaria a minas antipersona antes y durante el proceso de paz colombiano

Abstract Introduction: Although the peace process in Colombia resulted in a significant reduction in the number of anti-personnel mines across the country, there are no reliable data on the effects of this phenomenon on outcomes for patients who were victims of these devices. Objective: The objective of this study was to assess mortality from landmine injuries before and during the Colombian peace process. Furthermore possible associations between peace negotiations and mortality were explored. Methods: For this study, we used the "Colombian Victims of Antipersonnel Mines Injuries registry" (MAP/MUSE database) data from 2002 to 2018. This registry was launched in 2001 by the government of Colombia with the aim of prospectively and systematically collect information on all the cases of anti-personnel mine injuries in the country. The period between 2002-2012 was classified as the pre-negotiation period (período de guerra), and 2014-2018 as the peace negotiations period, with 2013 classified as a washout year. Multivariate logistic regression was used to explore the association between peace negotiations and mortality among anti-personnel landmine injured individuals. Results: A total of 10306 landmine injury cases were registered. Of these, 1180 (11.4%) occurred in the peace-negotiation period. Mortality was significantly lower during the period of peace negotiations. After adjusting for sex, age group, race, active duty soldier status, rural area, and geographic Departamentos case volumes, the peace negotiation period was found to be associated with lower risk-adjusted odds of mortality after suffering a landmine injury (OR= 0.6, 95% CI, 0.5-0.7; p<0.001). Conclusions: Our findings suggest an association between the period of peace negotiation and a lower likelihood of mortality among victims of anti-personnel landmines.

Resumen Introducción: Aunque el proceso de paz colombiano produjo una reducción en la cantidad de minas antipersona en el país, no hay estimativos sobre el efecto de este fenómeno en los desenlaces de los pacientes víctimas de estos artefactos. Objetivo: Nuestro objetivo fue evaluar la mortalidad por minas antipersona antes y durante la negociación del proceso de paz en Colombia. Además, exploramos posibles asociaciones entre las negociaciones de paz y la mortalidad. Métodos: Para este estudio utilizamos los datos del "Registro de víctimas colombianas de lesiones de minas antipersona" (base de datos MAP / MUSE) de 2002 a 2018. Este registro fue lanzado en 2001 por el gobierno de Colombia con el objetivo de recolectar información de manera prospectiva y sistemática de los casos de trauma por minas antipersona en el país. Clasificamos el período comprendido entre 2002 y 2012 como el período previo a la negociación (período de guerra), el comprendido entre 2014 y 2018 como el período de negociaciones de paz y el año 2013 como período de "depuración". Se utilizaron modelos de regresión logística multivariados para explorar las asociaciones entre las negociaciones de paz y la mortalidad. Resultados: Se registraron un total de 10306 casos de lesiones por minas antipersona. De estos, 1180 (11.4%) ocurrieron en el período de negociación de paz. La mortalidad fue significativamente menor durante el período de negociaciones de paz. El análisis de regresión logística multivariado determinó que el período de negociación de paz se asoció con una menor probabilidad de mortalidad después de sufrir una lesión por minas antipersona (OR = 0,6, IC 95%, 0,5-0,7; p <0,001). Conclusiones: Nuestros hallazgos sugieren una asociación entre el período de negociación de paz y una menor probabilidad de mortalidad entre las víctimas de las minas antipersona.

Diagnostic challenges in paediatric foreign body aspiration: a case report / Desafío diagnóstico en la aspiración de cuerpo extraño en pediatría: reporte de un caso

Abstract Introduction Foreign body aspiration (FBA) is a potentially fatal paediatric emergency. Our objective was to highlight the importance of a multidisciplinary approach to difficult/doubtful diagnosis. Case report 34-month-old girl referred for urgent rigid bronchoscopy after suspected metallic blade ingestion (found chewing on it). She had a previous recurrent history of wheezing. The physical examination revealed face/lip wounds, traces of powder on her teeth but no breathing difficulty. The plain X-Ray revealed radiopaque images of the upper pulmonary field and gastric chamber. In the absence of FBA clinical signs but considering a previous history of bronchial hyperresponsiveness, a direct digital radiographic study was performed. There were no images compatible with foreign bodies: the results were interpreted as artefacts and no bronchoscopy was performed. Conclusions A careful pre-anaesthetic evaluation, a high level of suspicion and excellent multidisciplinary communication led to the recognition of false radiologic findings. A conservative approach was followed and invasive procedures in a remote location, with high anaesthetic risk for the paediatric population were avoided.

Resumen Introducción La aspiración de cuerpo extraño (ACE) es una emergencia pediátrica potencialmente fatal. La intención del presente artículo es resaltar la importancia de un abordaje multidisciplinario en caso de un diagnóstico difícil/dudoso. Reporte de caso Se trata de una paciente de 4 meses de edad remitida para broncoscopia rígida de urgencia, luego de la sospecha de ingestión de una hojilla metálica (se encontró a la bebé mordiéndola). La paciente tenía antecedentes de sibilancia. Al examen físico se encontraron heridas en la cara y los labios, rastros de polvo en los dientes, pero no había dificultad respiratoria. El examen de rayos-x mostraba imágenes radio opacas en el cuadrante superior derecho del pulmón y en la cámara gástrica. En virtud de la ausencia de signos clínicos de ACE en una paciente con antecedentes de hiperresponsividad bronquial, se realizó un estudio radiográfico digital. No hubo imágenes compatibles con cuerpos extraños: los resultados se interpretaron como artefactos y no se realizó la broncoscopia. Conclusiones Un cuidadoso examen pre-anestesia, el alto grado de sospecha y una excelente comunicación multidisciplinaria, permitieron el reconocimiento de hallazgos radiológicos falsos. Se siguió un abordaje conservador, evitando así procedimientos invasivos en lugares remotos con alto grado de riesgo para la población pediátrica.

Influência de diferentes materiais obturadores endodônticos em imagens de TCFC: uma avaliação in vitro / Influence of different root canal obturation materials in CBCT imaging: an in vitro evaluation

Objetivo: O presente estudo avaliou a influência de materiais obturadores endodônticos na produção de artefato de imagens de tomografia computadorizada de feixe cônico (TCFC), por meio da análise de densidade de imagem em incisivos centrais e dentes pré-molares unirradiculares. Métodos: Os dentes foram submetidos a instrumentação endodôntica e divididos em cinco grupos: um grupo controle (sem preenchimento endodôntico) e quatro grupos teste, cada um preenchido por um material obturador endodôntico diferente (PulpCanal Sealer, AHPlus, Sealer26 e BCSealer). Após a aquisição da TCFC, as imagens foram avaliadas para determinar variações de tons de cinza nos três terços da raiz (análise objetiva). A segunda análise (subjetiva) comparou o grupo controle com dois dos grupos teste, em um processo randomizado. Resultados: Na análise objetiva, o Sealer26 e o BCSealer mostraram diferença estatística para valores mínimos, em comparação com outros materiais obturadores endodônticos, para dentes anteriores e posteriores. Para valores máximos, apenas o grupo controle diferiu estatisticamente dos grupos teste. Ao comparar os valores dos pré-molares e dos incisivos centrais em tons cinza pelo teste de Kruskal-Wallis, foi encontrada diferença estatisticamente significativa para os valores mínimos. Na análise subjetiva, para dentes anteriores e posteriores, o PulpCanal Sealer foi o material mais frequentemente apontado pelos observadores como aquele que produziu mais interferência de artefato. Conclusões: Os materiais obturadores endodônticos nos dentes posteriores apresentaram comportamento semelhante; somente o PulpCanal Sealer no terço apical apresentou diferenças estatísticas em relação aos demais grupos. Para os dentes anteriores, o BCSealer apresentou valores mínimos maiores em relação aos outros materiais obturadores endodônticos, o que poderia representar maior interferência do artefato (AU).

Objective: This study evaluated the influence of canal obturation materials in the production of cone beam computed tomography (CBCT) images artifact, by means of image density analysis and comparison between four materials in central incisors and monoradicular premolar teeth. Materials and Methods: The teeth were submitted to endodontic instrumentation and divided into 5 groups: one control group (no endodontic filling) and four test groups each one filled by a different endodontic sealer (PulpCanal Sealer, AHPlus, Sealer26 and BCSealer). After CBCT scanning, the images were assessed to determine grayscale variations in three root thirds (objective analysis). The second (subjective) analysis compared the control group with two of the test groups in a randomized process. Results: In the objective analysis, Sealer26 and BCSealer showed statistical difference for minimum values, in comparison with another sealers, for both anterior and posterior teeth. For maximum values, only control group differed statistically from test groups. When comparing premolars and central incisors grayscale values by ANOVA analysis, a statistically significant difference was found mainly for minimum values. At the subjective analysis, for both anterior and posterior teeth, PulpCanal Sealer was the filling most frequently appointed by the observers as the one that produced more artifact interference. Conclusion: Endodontic fillings at posterior teeth performed similar behavior. Only PulpCanal Sealer on apical third presented higher maximum values in relation to others groups, which could represent more white brands. For anterior teeth, BC Sealer performed higher minimum values in relation to other endodontic fillings, which could represent more dark bands (AU).

Research on automatic removal of ocular artifacts from single channel electroencephalogram signals based on wavelet transform and ensemble empirical mode decomposition / 生物医学工程学杂志

The brain-computer interface (BCI) systems used in practical applications require as few electroencephalogram (EEG) acquisition channels as possible. However, when it is reduced to one channel, it is difficult to remove the electrooculogram (EOG) artifacts. Therefore, this paper proposed an EOG artifact removal algorithm based on wavelet transform and ensemble empirical mode decomposition. Firstly, the single channel EEG signal is subjected to wavelet transform, and the wavelet components which involve EOG artifact are decomposed by ensemble empirical mode decomposition. Then the predefined autocorrelation coefficient threshold is used to automatically select and remove the intrinsic modal functions which mainly composed of EOG components. And finally the 'clean' EEG signal is reconstructed. The comparative experiments on the simulation data and the real data show that the algorithm proposed in this paper solves the problem of automatic removal of EOG artifacts in single-channel EEG signals. It can effectively remove the EOG artifacts when causes less EEG distortion and has less algorithm complexity at the same time. It helps to promote the BCI technology out of the laboratory and toward commercial application.

Progress of motion artifact correction in photoacoustic microscopy and photoacoustic tomography / 生物医学工程学杂志

Photoacoustic imaging (PAI) is a rapidly developing hybrid biomedical imaging technology, which is capable of providing structural and functional information of biological tissues. Due to inevitable motion of the imaging object, such as respiration, heartbeat or eye rotation, motion artifacts are observed in the reconstructed images, which reduce the imaging resolution and increase the difficulty of obtaining high-quality images. This paper summarizes current methods for correcting and compensating motion artifacts in photoacoustic microscopy (PAM) and photoacoustic tomography (PAT), discusses their advantages and limits and forecasts possible future work.

Aplicação de um novo software de TCFC com filtros específicos para redução de artefatos: série de casos / Application of a new CBCT software with specific filters for blooming artifact reduction: case series

Introdução: As obturações dos canais radiculares e os pinos intrarradiculares geralmente produzem artefatos de contraste branco e possíveis alterações volumétricas nas imagens de tomografia computadorizada de feixe cônico (TCFC). Esses artefatos, induzidos pela maior densidade dos materiais obturadores de canais radiculares, cimentos para colocação de coroa e pinos intracanais, podem potencialmente levar a interpretações incorretas, interferindo no diagnóstico de um volume adquirido de TCFC, principalmente na avaliação de potenciais fraturas e perfurações radiculares. Objetivos: Avaliar em seis casos clínicos os efeitos positivos e negativos dos artefatos de contraste branco no diagnóstico de fraturas radiculares, perfurações radiculares e cimentação de restaurações de porcelana. Métodos: O software e-Vol DX, que possui filtros específicos para redução de artefato de contraste (BAR, Blooming Artifact Reduction), foi usado para melhorar o valor diagnóstico dos volumes adquiridos de TCFC. Conclusões: O em- prego do software e-Vol DX para a reconstrução de imagens de TCFC melhorou a visualização das estruturas anatômicas e reduziu os artefatos. A visualização aprimorada de da- dos nas imagens pode auxiliar na identificação de detalhes essenciais que, em conjunto com os achados clínicos, são úteis para uma correta estruturação do diagnóstico (AU).

Introduction: Root canal fillings and intraradicular posts often create white contrast artifacts and possible volumetric changes on CBCT scans known as blooming artifacts. These alterations could lead to the incorrect interpretations reducing the diagnostic of an acquired CBCT volume, particularly when evaluating potential root fractures and root perforations. Methods and Results: In six clinical cases, the positive and negative effects of beam hardening artifacts on the diagnosis of root fractures, root perforations and porcelain restoration cementation were evaluated. These artifacts, induced by the higher density of root canal filling materials, cements for crown placement and intracanal posts, may potentially lead to inaccurate or false interpretations. A novel software, e-Vol DX, which has specific filters for blooming artifact reduction (BAR), was used to improve the diagnostic value of acquired CBCT volumes. Conclusions: The use of the e-Vol DX software package for the reconstruction of CBCT scans improved visualization of anatomical structures and reduced blooming artifacts. Improved data visualization may help reveal essential details that, in conjunction with clinical findings, are useful to achieve a correct diagnosis (AU).

Modos de habitar y creación fotográfica con jóvenes del Kilómetro 41 / Modes of living and photographic creation with young people from Kilometer 41 / Modos de vida e criação fotográfica com jovens do Quilômetro 41

Resumen (analítico) En este artículo de investigación cualitativa, la tecnología fotográfica y la memoria visual se convierten en plataformas para producir expresiones artísticas de reconciliación. En tal sentido, la creación fotográfica se usó como medio para exteriorizar significados e interpretaciones visuales sobre un territorio. Estudiantes de una institución educativa rural participaron en talleres de creación fotográfica y laboratorios de fundamentación sobre memoria y reconciliación. Este trabajo empírico permitió aplicar instrumentos de observación participante, explorando el acto creativo a través de una guía de elementos que potenciaron posturas críticas de los jóvenes hacia el territorio. Los resultados de un modelo de acciones creativas, aplicado a procesos de pensamiento crítico, permitieron comprobar que el autorretrato fotográfico se convierte en un artefacto comunicativo autorreferenciado socialmente.

Abstract (analytical) In this qualitative research article, photographic technology and visual memory are used in platforms to produce artistic expressions of reconciliation. Photographic creation was used to express meanings and visual interpretations of a territory. Students from a rural school participated in photographic creation workshops and activities focused on memory and reconciliation. This empirical work facilitated the application of participant observation instruments, exploring the act of creation through a handbook that promoted critical thinking for young people regarding the territory. The results of a creative action model applied to critical thought processes verified that the photographic self-portrait becomes a socially self-referenced communicative artifact.

Resumo (analítico) Neste artigo de pesquisa qualitativa, a tecnologia fotográfica e memória visual tornam-se plataformas para produzir expressões artísticas de reconciliação. Nesse sentido, a criação fotográfica foi utilizada como um meio de externalizar significados visuais e interpretações de um território. Os alunos da instituição educacional rural Giovanni Montini participam de oficinas de criação fotográfica e de laboratórios de fundamentação em memória e reconciliação. Este trabalho empírico permitiu a aplicação de instrumentos de observação participante, explorando o ato criativo por meio de um guia de elementos (estruturação, navegação, programação e representação) que impulsionaram as posições críticas dos jovens em relação ao território. Os resultados de um modelo de ações criativas, aplicadas aos processos de pensamento crítico, permitiram verificar que o autoretrato fotográfico torna-se um dispositivo comunicativo socialmente auto-referenciado.

Potential of a new cone-beam ct software for blooming artifact reduction

Abstract This study evaluated the dimensions of intraradicular posts using a new cone beam CT (CBCT) software, and verified the potential of blooming artifact reduction. Sixty-three single-rooted human teeth were shaped, obturated, prepared for intracanal post placement and distributed into three groups: G1: anatomically customized prefabricated glass fiber posts; G2: low-fusion alloy posts; G3: gold alloy posts. After post fabrication and luting with RelyX U200®, specimens were sectioned axially at 9 mm from the root apex, and markings were made on the root surfaces (X-, Y- and Z-axes). The dimensions of the original posts (control group) were measured using a digital micrometer. CBCT scans of the teeth were obtained using a PreXion 3D Elite® scanner. Posts were measured on CBCT scans using DICOM files and the e-Vol DX software. A specific filter, Blooming Artefact Reduction (BAR), was developed to analyze intracanal posts. Statistical data were evaluated using the Van de Waerden nonparametric analysis of variance and, after that, normalized data were analyzed using the Tukey test. The level of significance was set at α = 5%. The measures of the anatomical prefabricated, low-fusion alloy and gold alloy intracanal posts obtained using the e-Vol DX CBCT software and a micrometer were not significantly different (p>0.05). The use of the BAR filter of the e-Vol DX software application did not induce any dimensional differences on CBCT scans of intracanal posts when compared with measurements made with a micrometer on original posts. The use of the BAR filter eliminated blooming artifacts.

Resumo Este estudo avaliou as dimensões de pinos intrarradiculares usando um novo software de tomografia computadorizada de feixe cônico (TCFC) e um micrômetro digital, e verificou o potencial da redução do artefato de contraste do branco. Sessenta e três dentes humanos unirradiculares foram modelados, obturados, preparados para colocação de pinos e distribuídos em três grupos: G1: pino de fibra de vidro pré-fabricado anatômico; G2: pino metálico de liga de baixa fusão; G3: pino metálico de liga de ouro. Após a confecção e cimentação dos pinos com RelyX U200®, os espécimes foram cortados no sentido axial a 9 mm do ápice radicular, sendo efetuadas marcações em suas superfícies radiculares (eixos X, Y e Z) para orientação das medidas e sincronizações das imagens. Foi utilizado um micrômetro digital para a mensuração das dimensões dos pinos originais (grupo controle) associado ao microscópio operatório. Posteriormente, as imagens em TCFC foram obtidas usando o PreXion 3D Elite®. Para a mensuração dos pinos nas imagens de TCFC utilizou-se o arquivo DICOM e a ferramenta de medida do software e-Vol DX, configurada para medidas milesimais, com o filtro BAR (Blooming Artifact Reduction). Os dados estatísticos foram avaliados com a análise de variância não-paramétrica de Van der Waerden, seguida pelo Teste de Tukey aplicado aos dados normalizados. O nível de significância foi de α = 5%. Os resultados mostraram que as medidas dos diâmetros dos pinos intrarradiculares (fibra de vidro anatômico, metálico liga de baixa fusão, e em liga de ouro) usando o software e-Vol DX e o micrômetro não mostram diferenças significativas entre si. O uso do filtro BAR do software e-Vol DX não induziu diferenças dimensionais nas imagens de TCFC dos pinos quando comparadas às medidas realizadas com o micrômetro sobre os pinos originais. O uso do filtro BAR eliminou artefatos de contraste do branco.