Patrón de lectura radiológica digital para la clasificación de imágenes compatibles con silicosis / Digital reading radiation pattern for classification of image about silicosis (P0140-2013)

La silicosis es una enfermedad sin tratamiento. El programa de vigilancia de trabajadores expuestos a sílice está diseñado para detectarla lo más precozmente posible mediante una radiografía de tórax. A pesar de su rol fundamental, esta adolece de una gran variabilidad técnica y de interpretación. Para disminuir estos fenómenos, la OIT creó un sistema de clasificación ampliamente usado en Chile y el mundo. Este se basó en la radiografía análoga, la que ha sido reemplazada por el mismo set análogo, digitalizado. Si bien la OIT permite el uso de este nuevo tipo de imagen, indica que el patrón de comparación debe seguir siendo el análogo. Muchos estudios han demostrado que es mejor utilizar patrones de comparación digitales. El objetivo de este trabajo fue generar un set de radiografías digitales que representen las profusiones centrales de opacidades redondas del sistema de clasificación OIT. De un universo de 32.826 radiografías de pacientes expuestos a sílice, se obtuvo 252 radiografías, de las cuales 54 fueron informadas por 3 lectores acreditados, seleccionándose 8 casos que contaban con opacidades redondas puras de diferentes profusiones, las que se proponen como patrón digital para Chile.

Silicosis is a disease without treatment. The surveillance program for workers exposed to silica is designed to detect as early as possible by a chest radiograph. Despite its fundamental role, it suffers from a great technique and interpretation variability. To reduce these phenomena, the ILO created a classification system widely used in Chile and the world. This was based on analog radiography, which has been replaced by the same analog set, digitized. While the ILO permits the use of this new type of image it indicates that the pattern comparison must remain analog. Many studies have shown that it is best to use digital comparison patterns. The objective of this work was to generate a set of digital x-rays representing the central profusion of round opacities of ILO classification system. From a universe of 32,826 x-rays of patients exposed to silica, 252 films, of which 54 were reported for 3 accredited readers, selected 8 cases that had pure round opacities of different profusions was obtained, which are proposed as digital pattern for Chile.

Optimizing Imaging Quality and Radiation Dose by the Age-Dependent Setting of Tube Voltage in Pediatric Chest Digital Radiography

OBJECTIVE: The quality and radiation dose of different tube voltage sets for chest digital radiography (DR) were compared in a series of pediatric age groups. MATERIALS AND METHODS: Forty-five hundred children aged 0-14 years (yr) were randomly divided into four groups according to the tube voltage protocols for chest DR: lower kilovoltage potential (kVp) (A), intermediate kVp (B), and higher kVp (C) groups, and the fixed high kVp group (controls). The results were analyzed among five different age groups (0-1 yr, 1-3 yr, 3-7 yr, 7-11 yr and 11-14 yr). The dose area product (DAP) and visual grading analysis score (VGAS) were determined and compared by using one-way analysis of variance. RESULTS: The mean DAP of protocol C was significantly lower as compared with protocols A, B and controls (p < 0.05). DAP was higher in protocol A than the controls (p <0.001), but it was not statistically significantly different between B and the controls (p = 0.976). Mean VGAS was lower in the controls than all three protocols (p < 0.001 for all). Mean VGAS did not differ between protocols A and B (p = 0.334), but was lower in protocol C than A (p = 0.008) and B (p = 0.049). CONCLUSION: Protocol C (higher kVp) may help optimize the trade-off between radiation dose and image quality, and it may be acceptable for use in a pediatric age group from these results.

Radiografia do implante coclear: técnica adaptada para aparelho portátil / Cochlear implant radiography: technique adapted into a portable apparatus

Considerando a indisponibilidade de equipamentos avançados de aquisição de imagens nos centros cirúrgicos da maioria dos centros hospitalares e a importância fundamental que têm para o cirurgião uma visualização imediata do implante coclear logo após sua inserção, uma boa opção é a utilização da radiografia convencional. OBJETIVO: Descrever um método radiográfico rápido prático e de baixo custo, que permita avaliar não só a posição, mas também a integridade dos eletrodos, na instalação do implante coclear. MATERIAL E MÉTODO: Foram analisadas radiografias de 262 pacientes submetidos à cirurgia de implante coclear entre Março/2005 e Outubro/2008, com radiografia transoperatória, logo após a inserção dos eletrodos. As radiografias foram analisadas pelo cirurgião no transoperatório e, posteriormente, pelo médico radiologista. RESULTADOS: Foram analisadas 524 radiografias das quais, 95,61 por cento apresentavam técnica adequada, com posicionamento do paciente dentro da técnica descrita neste estudo e boa visualização dos eletrodos, sendo consideradas satisfatórias e 4,39 por cento apresentavam técnica inadequada e/ou visualização insatisfatória dos eletrodos, sendo consideradas insatisfatórias. CONCLUSÃO: Apesar dos aparelhos de Raios X portáteis possuírem limitações, utilizando técnicas e acessórios adequados, é possível conseguir radiografias com resultados satisfatórios para visualização dos implantes cocleares.

The unavailability of advanced imaging equipment in the operating rooms of most hospitals - as well as the fundamental importance for surgeons of immediate observation of the cochlear implants soon after their insertion - makes conventional radiography a good option. OBJECTIVE: To describe a practical, fast and low-cost radiographic method, allowing for evaluation of the electrodes regarding their position and integrity, during the insertion of cochlear implants. MATERIALS AND METHODS: Radiographies from 262 cochlear implant patients were analyzed, from March 2005 to October 2008, by means of intraoperative radiography, soon after electrode insertion. All radiographies were analyzed by the surgeon in the intraoperative period and, afterwards, by the radiologist. RESULTS: A total of 524 radiographies were analyzed, and 95.61 percent presented adequate technique - with the patient being positioned into the technique proposed in this study - as well as a clear visualization of the electrodes, regarded as satisfactory. On the other hand, 4.39 percent presented inadequate technique and/or unsatisfactory visualization of the electrodes, regarded as unsatisfactory. CONCLUSION: Although the portable X-ray apparatus presents limitations, the employment of proper techniques and accessories makes possible the obtainment of satisfactory radiographies to observe cochlear implants.

Development of Standard Digital Images for Pneumoconiosis

We developed the standard digital images (SDIs) to be used in the classification and recognition of pneumoconiosis. From July 3, 2006 through August 31, 2007, 531 retired male workers exposed to inorganic dust were examined by digital (DR) and analog radiography (AR) on the same day, after being approved by our institutional review board and obtaining informed consent from all participants. All images were twice classified according to the International Labour Office (ILO) 2000 guidelines with reference to ILO standard analog radiographs (SARs) by four chest radiologists. After consensus reading on 349 digital images matched with the first selected analog images, 120 digital images were selected as the SDIs that considered the distribution of pneumoconiosis findings. Images with profusion category 0/1, 1, 2, and 3 were 12, 50, 40, and 15, respectively, and a large opacity were in 43 images (A = 20, B = 22, C = 1). Among pleural abnormality, costophrenic angle obliteration, pleural plaque and thickening were in 11 (9.2%), 31 (25.8%), and 9 (7.5%) images, respectively. Twenty-one of 29 symbols were present except cp, ef, ho, id, me, pa, ra, and rp. A set of 120 SDIs had more various pneumoconiosis findings than ILO SARs that were developed from adequate methods. It can be used as digital reference images for the recognition and classification of pneumoconiosis.

Description of the technique of upper gastrointestinal series radiological examination for the evaluation of the esophagus, stomach and duodenum of Wistar female rats / Descrição de técnica radiológica contrastada de esôfago, estômago e duodeno em ratas Wistar

PURPOSE: To evaluate the anatomy of female Wistar rats and the workability of contrast radiography as a technique to investigate the gastrointestinal series. METHODS: Eight adult female Wistar rats were undergone to the contrast radiography as anteroposterior incidence and as posterior incidence in profile. The radiological examination was conducted at a 45° angle to the radiological table. Film-focus distance (FFD) was 100 cm, film-object distance (FOD) was 0 cm, and object-focus distance (OFD) was 100 cm. An orogastric probe was used to inject barium contrast at 5-min intervals, for a total of four applications. After the radiological examination, animals were necropsy for confirmation of the radiological findings, and the radiographs were the absence of the normal anatomy variations inspected and described by an experienced radiologist. RESULTS: All the radiographs produced achieved satisfactory results in terms of position, exposure, location and quality. The upper esophageal sphincter (UES) was identified in the esophagus at the nerve C2, the lower esophageal sphincter (LES) was identified between spinal cord segments L1 and L2, the thoracic-abdominal junction was observed at T10, the esophageal-gastric junction (EGJ) at T13-L1, with the abdominal portion in the epigastric region. The stomach was observed mostly in the epigastric region, left hypochondrium, left and mesogastric flank. The duodenum findings presented higher variation, with most findings identified in the epigastric region, right hypochondrium, right flank and mesogastric ileal fossa at T13-L5. CONCLUSION: Contrast radiology is useful and may be employed to assess the anatomy of the animal being studied. The experimental model described afforded to fully identify all organs investigated, as well as other occasional relevant findings. No anatomical anomalies in the subsequent necropsy, confirming the radiographic findings.

OBJETIVO: Avaliar a anatomia normal de ratas Wistar e a viabilidade do exame contrastado nesta população. MÉTODOS: Foram submetidas ao exame oito ratas Wistar adultas, em incidência Ântero-Posterior e Perfil. A técnica consiste no posicionamento à 45º de inclinação em relação à mesa radiológica e colocado à Distância Foco Filme (DFF) de 100 cm, Distância Objeto Filme (DOF) de 0 cm, Distância Foco Objeto (DFO) de 100 cm. O contraste baritado foi injetado via sonda nasoesofágica, em intervalos de 5 minutos para cada fase, em um total de quatro fases. Após a realização do exame foi realizada necropsia dos animais para confirmação dos achados radiológicos e da ausência de variações da anatomia normal As radiografias foram analisadas e descritas por radiologista experiente no exame. RESULTADOS: Todos os exames foram satisfatórios no que se refere ao posicionamento, exposição, localização e qualidade do exame. Foi identificado o esôfago com o Esfíncter Esofágico Superior (EES) ao nível de segunda vértebra cervical (C2) e Esfíncter Esofágico Inferior (EEI) entre as vértebras lombares (L1-2), transição toracoabdominal na vértebra Torácica (T10), Junção Esôfago Gástrica em T13-L1, com a porção abdominal em região epigástrica. O estômago, predominantemente, localizou-se em região epigástrica, hipocôndrio esquerdo, flanco esquerdo e mesogástrico. O duodeno teve a maior variação, com predomínio dos achados na região epigástrica, hipocôndrio direito, flanco direito, fossa ilíaca direita e mesogástrica e ao nível de T13-L5. CONCLUSÃO: O exame contrastado pôde avaliar a anatomia normal do animal em estudo e foi identificada de forma integral em todos os órgãos avaliados com o método descrito, achados confirmados em todos os animais em necropsia subseqüente.

Image quality in partially erased DenOptix® storage phosphor plates

This study aimed at investigating the effect of the partial erasing of DenOptix® system storage phosphor plates on the image quality of digital radiographs. Standardized digital radiographs were acquired of a phantom mandible, using size 2 intraoral DenOptix® storage phosphor plates (n = 10). Subsequently, the active areas of the plates were placed in a viewing box with a constant light intensity of 1,700 lux for 130 seconds to achieve complete erasing (control plate), as well as for 0, 5, 10, 15, 20, 25, 34, 66, and 98 seconds, to compose the experimental group of partially erased plates. The same exposure settings were repeated using the control and experimental plates, which were scanned at a resolution of 300 dpi. Five radiologists independently examined the pairs of digital radiographs obtained with the control and partially erased plates, in random order, and indicated the best image for oral diagnosis. Cochran-Mantel-Haenszel’s chi-square test, at a significance level of 5 percent, was used to compare the percentages of superior quality images in each combination of control and partially erased plates, subjectively assessed. No significant differences were found between radiographic images acquired with control and partially erased plates, except for the combination of 0 second (30 percent) versus 130 seconds (70 percent), p = 0.0047. It can be concluded that, under adequate light intensity conditions, erasing intraoral DenOptix® storage phosphor plates may require time intervals of as little as 5 seconds.

Reproducibility of pixel values for two photostimulable phosphor plates in consecutive standardized scannings / Reprodutibilidade dos valores de "pixels" de duas placas de fósforo fotoestimuláveis em leituras padronizadas consecutivas

The objective of the present study was to determine the reproducibility of the pixel values obtained with the Digora system (Soredex, Finland). Exposures were standardized, with variation in exposure and scanning time of two photostimulable phosphor plates containing a stepwedge image. The smallest variation in pixel values ranged from 50 to 75 percent, with the widest variations being observed in less dense steps. A significant difference in pixel values was observed in terms of X-ray exposure and scanning times and between the two plates themselves (ANOVA, p < 0.01). Using the present methodology, the reproducibility of pixel values was not satisfactory for the tested white photostimulable plates. This wide variation in digitalization might be influenced by the amount of X-rays that sensitized the plates. It may be important to establish the reproducibility of the pixel values in quantitative studies using digital image.

O objetivo do presente trabalho foi determinar a reprodutibilidade dos valores de "pixels" obtidos com o sistema Digora (Soredex, Finlândia). As exposições foram padronizadas, com variação no tempo de exposição e leitura de duas placas de fósforo fotoestimuláveis contendo a imagem de um penetrômetro. A menor variação nos valores de "pixels" foi de 50 a 75 por cento, sendo as maiores variações oriundas nas faixas mais claras. Uma diferença significante nos valores de "pixels" foi observada em relação ao tempo de exposição e leitura das placas e entre as duas placas (ANOVA, p < 0,01). Utilizando a presente metodologia, a reprodutibilidade dos valores de "pixels" das placas testadas do sistema Digora não foi satisfatória. Essa grande variação na digitalização pode ter sido influenciada pela quantidade de Raios X que sensibilizou as placas. Isso pode ser importante para estabelecer a reprodutibilidade dos valores de "pixels" em estudos quantitativos usando imagem digital.