Magnificación en la terapia endodóncica mediante el microscopio operatorio / Magnification in endodontic therapy through the operatory microscope

La microendodoncia involucra la visualización a través de un microscopio operatorio de todas las fases del tratamiento de conductos y procedimientos de cirugía apical y correctiva por parte del endodoncista. Existe sobrada evidencia acerca de las mejoras que puede aportar la magnificación al tratamiento; la literatura demuestra que la capacidad del operador mejora si su visión del campo gana claridad y precisión, ambos recursos pueden ser proporcionados por el microscopio operatorio, aunado a que posibilita diagnósticos más certeros junto con mejoras en el pronóstico, lo que permite evitar posibles complicaciones. La calidad de los tratamientos endodóncicos involucra infinidad de factores, cada uno relevante en sí mismo pero, en determinados casos, el microscopio puede significar la diferencia entre un tratamiento exitoso o un fracaso clínico. En la actualidad, se ha convertido en un tema de lo más relevante, por lo que el objetivo del presente trabajo es revisar la literatura con el fin de ayudar al entendimiento basado en evidencia científica de los criterios que determinan la relevancia del uso del microscopio en el ámbito endodóncico (AU)

Microendodontics involves the visualization through an operating microscope of all phases of root canal treatment and apical and corrective surgery procedures by the endodontist. There is plenty of evidence about the improvements that magnification can provide, the literature shows that the operator's ability improves if his vision of the field gains clarity and precision, both resources can be provided by the operating microscope, added to the fact that it enables more accurate diagnoses together with improvements in the prognosis allowing to avoid possible complications. The quality of endodontic treatments involves countless factors, each relevant in itself, but in certain cases the microscope can mean the difference between a successful treatment or a clinical failure. At present, it has become a very relevant topic, so the objective of this work is to review the literature in order to help understand the criteria that determine the relevance of the use of the microscope in the endodontic field based on scientific evidence (AU)

7. 0T ultrahigh-field MRI directly visualized the pedunculopontine nucleus in Parkinson's disease patients

OBJECTIVES: The pedunculopontine nucleus (PPN) is considered a promising new target for neurostimulation in Parkinson's disease (PD) patients with postural instability and gait disturbance that is refractory to other treatment modalities. However, the PPN is typically difficult to visualize with magnetic resonance imaging (MRI) at clinical field strengths, which greatly limits the PPN as a viable surgical target for deep brain stimulation (DBS). Thus, the aim of this study is to directly visualize the PPN based on 7.0T ultrahigh-field MRI. METHODS: Five PD patients were enrolled and scanned using the MP2RAGE sequence on a 7.0T ultrahigh-field MRI scanner. Then, the MP2RAGE sequences were imported into a commercially available navigation system. The coordinates of the directly localized PPN poles were recorded in the navigation system relative to the anterior commissure-posterior commissure plane. RESULTS: Our results indicated that the PPN presented intermediate signal intensity in the 7.0T ultrahigh-field MR images in comparison with the surrounding structure, such as the hypo-intensity of the periaqueductal gray and the hyperintensity of the neighboring white matter tracts, in PD patients. The mean coordinates for the rostral and caudal poles of PPN were 6.50 mm and 7.20 mm lateral, 1.58 mm and 2.21 mm posterior, and 8.89 mm and 13.83 mm relative to the posterior commissure. CONCLUSION: Our findings provide, for the first time, direct visualization of the PPN using the MP2RAGE sequence on a 7.0T ultrahigh-field MRI, which may improve the accuracy of stereotactic targeting of the PPN and improve the outcomes in patients undergoing DBS.

Evaluation of the Feasibility and Efficacy of Forward-Viewing Endoscopic Ultrasound

BACKGROUND/AIMS: We aimed to evaluate the feasibility and efficacy of a forward-viewing linear endoscopic ultrasound (FV-EUS) in diagnostic EUS procedures compared to standard oblique-viewing EUS (OV-EUS). METHODS: This study was a prospective, randomized study that permitted crossover. Fifty-one patients with subepithelial pancreatobiliary and upper gastrointestinal lesions underwent FV-EUS and OV-EUS sequentially, in random order. The EUS visualization was performed by a novice endosonographer, and the image quality of specific lesions was scored by an expert endosonographer. If fine-needle aspiration (FNA) was indicated, it was performed using both echoendoscopes by an expert endosonographer. RESULTS: Both of the EUS procedures had similar visualization times and image quality. In general, the visualization time was inversely related to the diameter of the specific lesions. In subepithelial lesions of the stomach and duodenum, the visualization time (98.8+/-62.2 seconds vs 139.0+/-66.6 seconds, p=0.008) and image quality (4.1+/-1.3 vs 3.3+/-1.7, p=0.02) of FV-EUS were significantly superior to OV-EUS. FV-EUS-guided FNA of pancreatic masses was successful in seven patients (87.5%). CONCLUSIONS: FV-EUS may increase the ease of access to gastrointestinal subepithelial lesions compared to conventional OV-EUS. The performance of FV-EUS for evaluating pancreatobiliary diseases and performing interventions was comparable to conventional OV-EUS.

Um sistema de auxílio ao diagnóstico da escoliose baseado em realidade aumentada / An auxiliary system for scoliosis diagnostic based on augmented reality

Este trabalho propõe e descreve uma ferramenta, chamada de SADE (Sistema de Auxílio ao Diagnóstico da Escoliose), capaz de auxiliar o fisioterapeuta no diagnóstico do desvio lateral da coluna vertebral do paciente (escoliose), observando-a pela visão posterior. Um dos métodos de diagnóstico utilizados atualmente é realizado por meio de um painel, chamado simetrógrafo, posicionado verticalmente e paralelo ao corpo do paciente. Nesse método tradicional o fisioterapeuta não trabalha com boas referências, pois o painel possui linhas espaçadas. Isso obriga o fisioterapeuta a se posicionar a uma certa distância do paciente durante o exame, impossibilitando a interação com o mesmo. Já o SADE, que é baseado em Realidade Aumentada, disponibiliza uma melhor visualização, pois a coluna real é virtualizada e comparada a uma coluna ideal virtual, possibilitando maior mobilidade do fisioterapeuta e do paciente durante o diagnóstico, já que a coluna virtualizada é visível pelos monitores. A ferramenta disponibiliza também o armazenamento dos dados capturados em banco de dados, possibilitando assim uma análise histórica e visual do início do tratamento até o estado atual. Testes realizados dentro de um laboratório desenvolvido especificamente para o projeto, onde o SADE, o simetrógrafo e o método de palpação foram comparados, caracterizam a ferramenta proposta como promissora para auxiliar o profissional no diagnóstico da escoliose.

The paper proposes and describes a tool called SADE (Auxiliary System for Scoliosis Diagnose), which is able to assist the physio­therapist in diagnosing the deviation of the patient’s vertebral spine (scoliosis) observed by the posterior view. One of the current diagnose methods uses a panel called simetrograph, vertically positioned and parallel to the patient’s body. This method does not provide the physiotherapist with a good reference because the panel has spaced lines. Besides, the simetrograph compels the physio­therapist to stay away from the patient in every exam, making the interaction between patient and professional difficult. The SADE, which is based on Augmented Reality, allows a better visualization because of a virtualized spine and the virtual ideal spine, and gives better mobility to the patient and to the physiotherapist during the exam since the spine is visible through the monitors. The system also stores data in a database, allowing an historical analysis from the beginning of the treatment until the current stage. Tests done in a laboratory specifically prepared for the project, compared SADE, the simetrograph and the touch method, and the results have shown that SADE may be a promising tool to assist the physiotherapist in the diagnosis of scoliosis.

Sistema automático para quantificação e visualização da aeração pulmonar em imagens de tomografia computadorizada de tórax: Sistema de Análise de Imagens Pulmonares – SAIP / Automatic system for quantification and visualization of lung aeration on chest computed tomography images: the Lung Image System Analysis – LISA

A tomografia computadorizada de alta resolução (TCAR) é o exame de escolha na avaliação diagnóstica de afecções do parênquima pulmonar. Neste particular, há um interesse crescente por sistemas computacionais capazes de analisar automaticamente a densidade radiológica dos pulmões. O principal objetivo deste trabalho é apresentar um sistema automático para quantificação e visualização do grau de aeração pulmonar (SAIP), em imagens de TCAR de pulmões com diferentes graus de alterações da aeração pulmonar. Como objetivo secundário comparar o SAIP ao sistema Osiris e a um algoritmo específico de segmentação pul­monar (SP), quanto à acurácia na segmentação do parênquima pulmonar. O SAIP disponibiliza atributos quantitativos extraídos automaticamente, tais como perímetro, área e volume da secção pulmonar, bem como o histograma de faixa de densidades ra­diológicas e acumulado, densidade pulmonar média (Dpm) em unidades Hounsfield (UH), área relativa dos voxels com densi­dade menor que –950 UH (RA950) e os valores de 15° percentil de baixa atenuação (PERC15). Além disso, é capaz de processar imagens por meio de uma ferramenta de máscara colorida, que aplica pseudo­cores no parênquima pulmonar, conforme faixas de densidade radiológicas pré­determinadas. Os resultados da segmentação pulmonar são comparados para um conjunto de 102 imagens de 8 voluntários saudáveis e 141 imagens de 11 pacientes com doença pulmonar obstrutiva crônica (DPOC). Quanto à segmentação, o SAIP se apresenta mais efetivo do que os outros dois métodos. O SAIP constitui uma ferramenta pro­missora no auxílio ao diagnóstico de enfisema em pacientes com DPOC, com grande potencial de aplicação nesta área e em outras doenças pulmonares.

High Resolution Computed Tomography (HRCT) is the exam of choice for the diagnostic evaluation of lung parenchyma diseases. There is an increasing interest for computational systems able to automatically analyze the radiological densities of the lungs in CT images. The main objective of this study is to present a system for the automatic quantification and visualization of the lung aeration in HRCT images of different degrees of aeration, called Lung Image System Analysis (LISA). The secondary objective is to compare LISA to the Osiris system and also to specific algorithm lung segmentation (ALS), on the accuracy of the lungs segmentation. The LISA system automatically extracts the following image attributes: lungs perimeter, cross sectional area, volume, the radiological densities histograms, the mean lung density (MLD) in Hounsfield units (HU), the relative area of the lungs with voxels with density values lower than –950 HU (RA950) and the 15th percentile of the least density voxels (PERC15). Furthermore, LISA has a colored mask algorithm that applies pseudo-colors to the lung parenchyma according to the pre-defined radiological density chosen by the system user. The lungs segmentations of 102 images of 8 healthy volunteers and 141 images of 11 patients with Chronic Obstructive Pulmonary Disease (COPD) were compared on the accuracy and concordance among the three methods. The LISA was more effective on lungs segmentation than the other two methods. LISA’s color mask tool improves the spatial visualization of the degrees of lung aeration and the various attributes of the image that can be extracted may help physicians and researchers to better assess lung aeration both quantitatively and qualitatively. LISA may have important clinical and research applications on the assessment of global and regional lung aeration and therefore deserves further developments and validation studies.

An approach to automatically segment the media-adventitia borders in IVUS / Uma associação de técnicas para segmentação automática da fronteira da média-adventícia em IVUS

Por ser capaz de mostrar aspectos morfológicos e patológicos de ateroscleroses, o Ultrassom Intravascular (IVUS) se tornou uma das modalidades de imagens médicas mais confiáveis e empregadas em intervenções cardíacas. As características de sua imagem aumentam as chances de um bom diagnóstico, resultando em terapias mais precisas. O estudo de segmentação da fronteira média-adventícia, dentre muitas aplicações, é importante para o aprendizado das propriedades mecânicas e determinação de algumas medidas específicas (raio, diâmetro, etc.) em vasos e placas. Neste trabalho, uma associação de técnicas de processamento de imagens está sendo proposta para atingir alta acurácia na segmentação da borda média-adventícia. Para tanto, foi feita uma combinação das seguintes técnicas: Redução do Speckle por Difusão Anisotrópica (SRAD), Wavelet, Otsu e Morfologia Matemática. Primeiramente, é usado SRAD para atenuar os ruídos speckle. Posteriormente, é executada Transformada Wavelet para extração das características dos vasos e placas. Uma versão binarizada dessas características é criada na qual o limiar ótimo é definido por Otsu. Finalmente, é usada Morfologia Matemática para obtenção do formato da adventícia. O método proposto é avaliado ao segmentar 100 imagens de alta complexidade, obtendo uma média de Verdadeiro Positivo (TP(%)) = 92,83 ± 4,91, Falso Positivo (FP(%)) = 3,43 ± 3,47, Falso Negativo (FN(%)) = 7,17 ± 4,91, Máximo Falso Positivo (MaxFP(mm)) = 0,27 ± 0,22, Máximo Falso Negativo (MaxFN(mm)) = 0,31 ± 0,2. A eficácia do nosso método é demonstrada, comparando este resultado com outro trabalho recente na literatura.

By being able to show morphological and pathological aspects of atherosclerosis, the Intravascular Ultrasound (IVUS) be¬came one of the most reliable and employed medical imaging modality in cardiac interventions. Its image characteristics in¬crease the chances of a good diagnostic, resulting in a precise therapy. The study of media-adventitia borders segmentation in IVUS, among many applications, is important for learning about the mechanical properties and determining some specific measurements (radius, diameter, etc.) in vases and plaques. An approach is proposed to achieve high accuracy in media-adventitia borders segmentation, by making a combination of different image processing operations: Speckle Reducing Anisotropic Diffusion (SRAD), Wavelet, Otsu and Mathematical Morphology. Firstly, SRAD is applied to attenuate the speckle noise. Next, the vessel and plaque features are extracted by performing Wavelet Transform. Optimal thresholding is car¬ried out by Otsu method to create a binarized version of these features. Then, Mathematical Morphology operations are used to obtain an adventitia shape. The proposed approach is evaluated by segmenting 100 challenging images, obtaining an average of True Positive (TP(%)) = 92.83 ± 4.91, False Positive (FP(%)) = 3.43 ± 3.47, False Negative (FN(%)) = 7.17 ± 4.91, Max False Positive (MaxFP(mm)) = 0.27 ± 0.22, Max False Negative (MaxFN(mm)) = 0.31 ± 0.2. The effectiveness of our approach is demonstrated by comparing this result with another recent work in the literature.

Variation of hepatic artery by 3-D reconstruction MDCT scan of liver in Siriraj Hospital.

OBJECTIVE: To evaluate the prevalence of hepatic arterial variant in Siriraj Hospital. MATERIAL AND METHOD: A retrospective study that was approved by ethic committee of Siriraj Hospital. Between August and October 2006, 200 studies of abdominal MDCT were randomly sampled and multi-planar reformatted by using program Vitrea 2. Both axial, two- and three-dimensional images were evaluated for possible variants of hepatic vasculature. The results were classified by Michel classification and analyzed in percentage. Moreover, a small group (23 studies) that had digital subtraction angiography (DSA) was compared to know accuracy and Intercorelation between the two reviewers (Kappa value). RESULTS: Of 200 studies, 83.5% had type I, 1% type II, 6% type III, 0.5% type IV, 3.5% type V, 1% type VI, 0.5% type VIII, 1% type IX, 0.5% Type X, and 2.5% others type. Accuracy of MDCT for detection hepatic artery variation as compared with DSA was 78.3%. CONCLUSION: All variation is about 16%. Type III is most common variation of patients in Siriraj Hospital.

Mini-open reduction and intramedullary interlocking nailing of fracture shaft of tibia without an image intensifier.

Intramedullary interlocking tibial nailing is usually performed using an image intensifier. But being expensive, it is not available in the most of the hospitals of resource-poor countries of the world. The purpose of this study is to analyze the results of interlocking nailing without the use of an image intensifier. This is the retrospective study of 55 diaphyseal tibial fractures treated with minimally open reduction and internal fixation with interlocked intramedullary nail fixation. The proximal locking of the nail with the screws was made using external jig and for the distal locking direct visualization of the hole was carried out. There were 15 females and 40 males. The average age in years was 32 with a range of 18 to 64 years. The surgical approach was medial parapatellar. The average follow up period was 4 months. This period ranged from 3 months to 14 months. The union time in an average was 4 months. The complication mainly was distal screw loosening leading to valgus deformity and shortening in 1 case. It is, therefore, concluded that interlocking intramedullary nailing can be performed with proximal and distal locking accurately without the use of an image intensifier.

Medindo o poder refrativo de lentes de contato gelatinosas personalizadas / Measuring the refractive power of customized soft contact lenses

OBJETIVO: Lentes de contato gelatinosas com curvas-base esféricas têm sido usadas há anos. O cálculo do poder refrativo de lentes deste tipo é fácil, bastando utilizarmos a equação do fabricante de lentes para lentes espessas. No entanto, para projetos de lentes de contato personalizadas, não há ainda métodos confiáveis para medida das aberrações ópticas de ordem mais alta. Esse trabalho foi desenvolvido no laboratório do Centro de Ciências da Visão (Center for Visual Science) da Universidade de Rochester, Nova York, com aparelho óptico que permite realizar medidas precisas de aberrações de ordem baixa e alta de lentes de contato gelatinosas personalizadas. Este é um passo essencial na verificação e obtenção de lentes de contato personalizadas de qualidade, e o instrumento desenvolvido na Universidade de Rochester permite verificar a qualidade de fabricação destas lentes. MÉTODOS: Um aparelho óptico de bancada foi montado em laboratório. Este aparelho consiste de uma célula úmida onde as lentes de contato são depositadas. Consiste também de uma série de lentes e espelhos e um sensor de frente-de-onda de Hartmann-Shack. As lentes de contato personalizadas utilizadas neste projeto foram fabricadas pela empresa Bausch & Lomb. Das dezenas de lentes de contato mensuradas no aparelho, restringimos aqui a apresentar os resultados de uma lente personalizada para ceratocone. RESULTADOS: O erro quadrático médio (EQM) do instrumento foi de 0,04 micrômetro, sendo que o EQM das aberrações induzidas na lente está entre 4 e 6 micrômetros, ou seja, a precisão do aparelho está em torno de 1 por cento. Este valor é mais do que suficiente para medidas precisas destes tipos de lentes de contato, algo até então inviável utilizando-se os sensores ou aparelhos convencionais de aberrometria. CONCLUSÃO: Com o instrumento desenvolvido neste trabalho foi possível realizar medidas precisas de aberrações de alta ordem. Esta tecnologia é importante para o desenvolvimento...

PURPOSE: Soft contact lenses with spherical base curves have been used for many years. The computation of the refractive powers of these lenses is easy, requiring only that one uses the lens maker equation for thick lenses. Nevertheless, for customized contact lenses, there is yet no reliable method for measuring the higher order optical aberrations. In this study we have developed in the Center for Visual Sciences of the University of Rochester an optical apparatus that allows for precise measurement of low and high order aberrations of customized soft contact lenses. METHODS: An optical apparatus was mounted on a conventional optical bench. This apparatus consists of a wet cell where the contact lenses are placed, a series of relay lenses, mirrors, beam splitters, and a Hartmann-Shack sensor. Bausch & Lomb manufactured the lenses used in this study. RESULTS: The root mean square error (RMSE) of the instrument was 0.04 microns. Given that the RMSE of the customized lens is between 4 and 6 microns, i.e., the precision of the instrument is approximately 1 percent. This precision is more than sufficient for the type of measurements necessary for manufacturing customized contact lenses. CONCLUSION: The instrument developed is extremely precise for measuring high order aberrations - up to the 10th order Zernike polynomials, that is, up to the 66th term. This technology is important for the development of new methods of optical corrections for patients that usually do not adapt to normal sphere-cylinder spectacles or that cannot undergo refractive surgery, such as those which have keratoconus, for example.

Estado actual de la ecocardiografía de contraste en la perfusión miocárdica / Contrast echocardiography in myocardial perfusion today

Avances en la ingeniería ultrasónica han llevado a la creación de micropartículas "inteligentes" con capacidad de atravesar en cantidad suficiente la barrera pulmonar transcapilar para permitir la obtención de imágenes de corazón izquierdo, lo que ha hecho posible la evaluación de la perfusión miocárdica. Si bien la Food and Drug Administration de los Estados Unidos ha aprobado varios agentes de contraste para empleo en opacificación ventricular y visualización de bordes endocárdicos en sujetos que tienen estudios subóptimos, no ha aprobado hasta el momento ningún agente de contraste para uso en perfusión miocárdica. En la actualidad existen dos estudios multicéntricos a gran escala que fueron diseñados exclusivamente para perfusión miocárdica en comparación con medicina nuclear y coronariografía. Nuestro laboratorio ha tenido la oportunidad de participar activamente en ambos estudios. Esta revisión incluye el diseño, criterios de interpretación y resultados preliminares de CARDIOsphere. Además, presentamos criterios de interpretación del estudio con la burbuja AI-700 que se encuentra actualmente en fase III de investigación clínica. La ecocardiografía de contraste para perfusión miocárdica enfrenta varios retos que deberá resolver antes de que se establezca como una alternativa eficiente. Una limitante común es la aplicabilidad de este método en sujetos con mala ventana acústica, la creación de artefactos intrínsecos al sistema como son la atenuación distal y lateral, la inevitable curva de aprendizaje, y el establecimiento de criterios en la cuantificación de los defectos.

Advances in ultrasonic engineering have made possible the development of "intelligent" micro-particles with the capacity of passing through the pulmonary circulation in sufficient amount to acquire images of the left heart, making possible the evaluation of myocardial perfusión. Although the Food and Drug Administration of the United States has approved several contrast agents for use in ventricular opacification and visualization of endocardial borders in subjects that have sub-optimal studies, at this time, it has not approved any agent of contrast for use in myocardial perfusión. Currently, there are two multicenter studies on a great scale that were exclusively designed for myocardial perfusión in comparison with nuclear medicine and angiography. Our laboratory has had the opportunity to actively participate in both trials. This revision includes the design, interpretation criteria, and preliminary results of CARDIOsphere. As well, we are presenting the interpretation criteria of the AI-700 bubble, which is currently in phase III of clinical investigation. Myocardial perfusión assessment with contrast echocardiography faces several challenges that need to be addressed before it becomes established as an efficient alternative. A common limitation is the viability of this method in subjects with bad acoustic window, the creation of intrinsic artifacts to the system, as distal and lateral attenuation; the unavoidable learning curve, and the settlement of defect quantification criteria. (Arch Cardiol Mex 2005; 75: 197-209).

Digital image analysis as an alternative method for photometric and spectrophotometric measurements

The author proposes a new and easy low cost system as an alternative method for the classical apparatus usually used in the field of photometric and spectrophotometric measurements. The proposed system depends on digital image analysis and it is composed from an imaging unit [Scanner or Camera CCD] computer, capillary tubes support, software [especially programmed for this purpose] and a printer. The author demonstrates the different functions of this system such as a spectrophotometer for colorimetric determination in visible light and he gives one of the phenols colorimetric determination as an example and as a densitometer in electrophoresis measurements for separated and stained serum proteins. A comparison of the same sample results with a classical densitometer [Helena] is exposed. In addition to the possibility of its application in T.L.C to determine quantitatively the separated spots, the use of this method in the field of fluorimetric measurements has been discussed