Comparison of 3D Volumetric Subtraction Technique and 2D Dynamic Contrast Enhancement Technique in the Evaluation of Contrast Enhancement for Diagnosing Cushing's Disease

PURPOSE: The purpose of this study is to compare the performance of the T1 3D subtraction technique and the conventional 2D dynamic contrast enhancement (DCE) technique in diagnosing Cushing's disease. MATERIALS AND METHODS: Twelve patients with clinically and biochemically proven Cushing's disease were included in the study. In addition, 23 patients with a Rathke's cleft cyst (RCC) diagnosed on an MRI with normal pituitary hormone levels were included as a control, to prevent non-blinded positive results. Postcontrast T1 3D fast spin echo (FSE) images were acquired after DCE images in 3T MRI and image subtraction of pre- and postcontrast T1 3D FSE images were performed. Inter-observer agreement, interpretation time, multiobserver receiver operating characteristic (ROC), and net benefit analyses were performed to compare 2D DCE and T1 3D subtraction techniques. RESULTS: Inter-observer agreement for a visual scale of contrast enhancement was poor in DCE (κ = 0.57) and good in T1 3D subtraction images (κ = 0.75). The time taken for determining contrast-enhancement in pituitary lesions was significantly shorter in the T1 3D subtraction images compared to the DCE sequence (P < 0.05). ROC values demonstrated increased reader confidence range with T1 3D subtraction images (95% confidence interval [CI]: 0.94–1.00) compared with DCE (95% CI: 0.70–0.92) (P < 0.01). The net benefit effect of T1 3D subtraction images over DCE was 0.34 (95% CI: 0.12–0.56). For Cushing's disease, both reviewers misclassified one case as a nonenhancing lesion on the DCE images, while no cases were misclassified on T1 3D subtraction images. CONCLUSION: The T1 3D subtraction technique shows superior performance for determining the presence of enhancement on pituitary lesions compared with conventional DCE techniques, which may aid in diagnosing Cushing's disease.

Effectiveness of digital subtraction radiography in detecting artificially created osteophytes and erosions in the temporomandibular joint

PURPOSE: Erosions and osteophytes are radiographic characteristics that are found in different stages of temporomandibular joint (TMJ) osteoarthritis. This study assessed the effectiveness of digital subtraction radiography (DSR) in diagnosing simulated osteophytes and erosions in the TMJ. MATERIALS AND METHODS: Five intact, dry human skulls were used to assess the effectiveness of DSR in detecting osteophytes. Four cortical bone chips of varying thicknesses (0.5 mm, 1.0 mm, 1.5 mm, and 2.0 mm) were placed at the medial, central, and lateral aspects of the condyle anterior surface. Two defects of varying depth (1.0 mm and 1.5 mm) were created on the lateral, central, and medial poles of the condyles of 2 skulls to simulate erosions. Panoramic images of the condyles were acquired before and after artificially creating the changes. Digital subtraction was performed with Emago dental image archiving software. Five observers familiar with the interpretation of TMJ radiographs evaluated the images. Receiver operating characteristic (ROC) analysis was used to evaluate the diagnostic accuracy of the imaging methods. RESULTS: The area under the ROC curve (Az) value for the overall diagnostic accuracy of DSR in detecting osteophytic changes was 0.931. The Az value for the overall diagnostic accuracy of panoramic imaging was 0.695. The accuracy of DSR in detecting erosive changes was 0.854 and 0.696 for panoramic imaging. DSR was remarkably more accurate than panoramic imaging in detecting simulated osteophytic and erosive changes. CONCLUSION: The accuracy of panoramic imaging in detecting degenerative changes was significantly lower than the accuracy of DSR (P<.05). DSR improved the accuracy of detection using panoramic images.

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.

Avaliação clínica e por imagem do efeito do tratamento periodontal mecânico não cirúrgico associado à aplicação tópica de alendronato de sódio a 1% no reparo periodontal: ensaio clínico randomizado controlado / Clinical and imaging of the effect of mechanical periodontal treatment nonsurgical associated with topical application of alendronate sodium 1% in periodontal repair reviewed randomized controlled trial

O alendronato de sódio é utilizado, na área médica, no tratamento da osteoporose e outras doenças ósseas. Nos últimos anos alguns estudos avaliaram o efeito do uso sistêmico do alendronato, principalmente, em defeitos ósseos decorrentes da evolução da doença periodontal inflamatória. Todavia, o uso sistêmico e prolongado do alendronato tem sido associado à osteonecrose dos maxilares. O objetivo deste ensaio clínico controlado randomizado foi avaliar o efeito do tratamento periodontal mecânico não cirúrgico, associado à aplicação tópica de alendronato de sódio a 1%, em indivíduos com periodontite. Para tanto, 16 indivíduos com periodontite crônica foram selecionados nas clínicas de Periodontia do Departamento de Odontologia da Pontifícia Universidade Católica de Minas Gerais, no período de abril de 2013 a maio de 2014...

Alendronate Sodium is medically used in the treatment of osteoporosis and other bone diseases. In the past few years, studies have evaluated the effect of systemic use of Alendronate Sodium, especially in the treatment of structural bone defects caused by the evolution of periodontal inflammatory diseases. However, the prolonged and systemic use of Alendronate Sodium has been associated with the treatment of osteonecrosis of the maxilla. The objective of this randomized and controlled clinical trial was to evaluate the effect of non-surgical mechanical periodontal treatment, associated with the topical application of Alendronate Sodium at 1%, to individuals presenting cases of periodontitis. To the case, 16 individuals presenting chronic periodontitis were selected in the periodontal clinics of the Odontology department from the Pontifícia Universidade Católica de Minas Gerais, in the period of April of 2013 to May of 2014. A complete periodontal exam was performed three and six months after the base exam, registeringthe following clinical parameters: probing depth, measured insertion loss, bleeding on probing, plaque index. The evaluation of the bone defects was performed using the technics of subtraction radiography and cone beam computerized tomography in the base exam and six months after the non-surgical ...(AU)

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...

Treatment of Intrabony Defects with Anorganic Bone Matrix/P-15 or Guided Tissue Regeneration in Patients with Aggressive Periodontitis

Intrabony periodontal defects present a particular treatment problem, especially in patients with generalized aggressive periodontitis (G-AgP). Regenerative procedures have been indicated for this clinical situation. The aim of this study was to compare treatment outcomes of intrabony periodontal defects with either anorganic bone matrix/cell binding peptide (ABM/P-15) or guided tissue regeneration (GTR) in patients with G-AgP. Fifteen patients, with two intrabony defects ≥3 mm deep, were selected. Patients were randomly allocated to be treated with ABM/P-15 or GTR. At baseline and at 3 and 6 months after surgery, clinical and radiographic parameters and IL-1β and IL-6 gingival fluid concentrations were recorded. There was a significant probing pocket depth reduction (p<0.001) for both groups (2.27 ± 0.96 mm for ABM/P-15 group and 2.57 ± 1.06 mm for GTR group). Clinical attachment level gain (1.87 ± 0.94 mm for ABM/P-15 group and 2.09 ± 0.88 mm for GTR group) was also observed. There were no statistically significant differences in clinical parameters between the groups. The radiographic bone fill was more expressive in ABM/P-15 group (2.49 mm) than in GTR group (0.73 mm). In subtraction radiographs, the areas representing gain in density were 93.16% of the baseline defect for ABM/P-15 group versus 62.03% in GRT group. There were no statistically significant differences in inter-group and intra-group comparisons with regards to IL-1β and IL-6 quantification. Treatment of intrabony periodontal defects in patients with G-AgP with ABM/P-15 and GTR improved significantly the clinical outcomes. The use of ABM/P-15 promoted a better radiographic bone fill.

Defeitos periodontais infra-ósseos representam um desafio particular no tratamento, especialmente em pacientes com periodontite agressiva generalizada (PAg-G). Procedimentos regenerativos tem sido indicados para esta situação clínica. O objetivo deste estudo foi comparar os resultados do tratamento de defeitos periodontais infra-ósseos com associação de matriz óssea inorgânica bovina com o P-15 (MOI/P-15) ou regeneração tecidual guiada (RTG) em pacientes com PAg-G. 15 pacientes com PAg-G, com pelo menos dois defeitos periodontais infra-ósseos (profundidade de sondagem ≥4 mm e componente infra-ósseo ≥3 mm) foram selecionados. Os pacientes foram aleatoriamente alocados para serem tratados com MOI/P-15 ou RTG. No exame inicial, e aos 3 e 6 meses após a cirurgia, os parâmetros clínicos e radiográficos e as concentrações de IL-1β e IL-6 no fluido gengival foram registrados. Houve uma redução significativa profundidade de sondagem (p<0,001) para ambos os grupos (2,27 ± 0,96 mm para o grupo MOI/P-15 e 2,57 ± 1,06 mm para o grupo RTG). Um ganho no nível clínico de inserção (1,87 ± 0,94 mm para o grupo MOI/P-15 e 2,09 ± 0,88 mm para o grupo RTG) também foi observado. Na comparação entre grupos, não houve diferenças estatisticamente significativas nos parâmetros clínicos. O preenchimento ósseo radiográfico foi mais expressivo no grupo MOI/P-15 (2,49 mm) do que no grupo RTG (0,73 mm). Na análise radiográfica, as radiografias de subtração apresentaram ganho médio de área radiopaca em relação ao defeito inicial de 93,16% para grupo MOI/P-15, contra 62,03% para o grupo RTG. Na análise das citocinas, não foram observadas diferenças estatisticamente significantes nas comparações intra e entre os grupos. O tratamento de defeitos infra-ósseos com MOI/P-15 ou RTG em pacientes com PAg-G, em um período de 6 meses, levou a melhoras nos parâmetros clínicos. O uso de MOI/P-15 levou a um maior preenchimento radiográfico.

Preliminary Experience Using Dynamic MRI at 3.0 Tesla for Evaluation of Soft Tissue Tumors

OBJECTIVE: We aimed to evaluate the use of dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) at 3.0 T for differentiating the benign from malignant soft tissue tumors. Also we aimed to assess whether the shorter length of DCE-MRI protocols are adequate, and to evaluate the effect of temporal resolution. MATERIALS AND METHODS: Dynamic contrast-enhanced magnetic resonance imaging, at 3.0 T with a 1 second temporal resolution in 13 patients with pathologically confirmed soft tissue tumors, was analyzed. Visual assessment of time-signal curves, subtraction images, maximal relative enhancement at the first (maximal peak enhancement [Emax]/1) and second (Emax/2) minutes, Emax, steepest slope calculated by using various time intervals (5, 30, 60 seconds), and the start of dynamic enhancement were analyzed. RESULTS: The 13 tumors were comprised of seven benign and six malignant soft tissue neoplasms. Washout on time-signal curves was seen on three (50%) malignant tumors and one (14%) benign one. The most discriminating DCE-MRI parameter was the steepest slope calculated, by using at 5-second intervals, followed by Emax/1 and Emax/2. All of the steepest slope values occurred within 2 minutes of the dynamic study. Start of dynamic enhancement did not show a significant difference, but no malignant tumor rendered a value greater than 14 seconds. CONCLUSION: The steepest slope and early relative enhancement have the potential for differentiating benign from malignant soft tissue tumors. Short-length rather than long-length DCE-MRI protocol may be adequate for our purpose. The steepest slope parameters require a short temporal resolution, while maximal peak enhancement parameter may be more optimal for a longer temporal resolution.

Efficacy of four irrigation needles in cleaning the apical third of root canals

This study aimed to evaluate the influence of irrigation needle gauge and design, and the final root canal diameter on the apical cleaning efficacy. Twelve human mandibular incisors were used. At different stages of root canal widening (sizes 20, 30 and 40 K-files), root canals were filled with radiopaque contrast medium. Four different needles were evaluated: 23G with side opening, 22G with apical opening, 30G with side opening and 30G with apical opening. Irrigation was carried out with 2 mL distilled water. The same tooth was radiographed with a digital system several times to assess the four types of needle in those three stages of canal widening. Pre-irrigation (canals filled with contrast) and post-irrigation (canals with remaining contrast) images were submitted to digital subtraction using the Adobe Photoshop CS4 program. Pre-irrigation (filled with contrast) and subtracted (cleaned by irrigation) areas were outlined by a trained and blinded operator using the Image Tool 3.0 software. Their ratio was calculated to express the percentage of apical cleaning in each stage of canal widening (sizes 20, 30 and 40 K-files) with each of the four needles. Data obtained were subjected to one-way ANOVA and Tukey's tests. The 30G needles with side and apical opening promoted better apical cleaning at all stages of root canal widening (p<0.05). In conclusion, smaller diameter needles were more efficacious in cleaning the apical third of the root canals, regardless of their design.

Este estudo teve como objetivo avaliar a influência do diâmetro e design da agulha de irrigação e do diâmetro do canal radicular na eficácia de limpeza apical. Doze incisivos mandibulares humanos foram utilizados. Em diferentes fases de alargamento do canal radicular (limas tipo K #20, 30 e 40), os canais foram preenchidos com meio de contraste radiopaco. Quatro agulhas diferentes foram avaliadas: 23G com abertura lateral, 22G com abertura apical, 30G com abertura lateral e 30G com abertura apical. A irrigação foi realizada com 2 mL de água destilada. O mesmo dente foi radiografado por um sistema digital, repetidas vezes, para avaliar os quatro diferentes tipos de agulha nas três fases de alargamento do canal. As imagens pré-irrigação (preenchidas por contraste) e pós-irrigação (com contraste restante) foram submetidas à subtração digital por meio do programa Adobe Photoshop CS4. As áreas pré-irrigação (preenchidas por contraste) e subtraídas (limpas pelo irrigante) foram demarcadas por um operador treinado e cego em relação aos grupos experimentais, usando o programa Image Tool 3.0. A proporção dessas duas medidas foi calculada para expressar a porcentagem de limpeza apical em cada estágio de dilatação (20, 30 e 40) com cada agulha. Os dados obtidos foram submetidos aos testes ANOVA a um critério e Tukey com nível de significância de 5%. As agulhas 30G com abertura lateral e apical promoveram melhor limpeza apical em todas as fases de ampliação do canal radicular (p<0,05). Em conclusão, as agulhas de menor diâmetro foram mais eficazes na limpeza do terço apical dos canais radiculares, independentemente do seu design.

Expresión diferencial de proteínas en Leishmania (Viannia) panamensis asociadas con mecanismos de resistencia a antimoniato de meglumina / Differential expression of proteins in Leishmania (Viannia) panamensis associated with mechanisms of resistance to meglumine antimoniate.

Introducción. Los mecanismos de resistencia al antimonio pentavalente conocidos hasta el momento, se han descrito ampliamente en cepas del subgénero Leishmania, pero poco se sabe sobre las proteínas involucradas en los mecanismos de resistencia presentes en cepas del subgénero Viannia, como Leishmania panamensis. Objetivo. Identificar proteínas diferencialmente expresadas entre las cepas de L. panamensis (UA140), sensible y resistente al antimonio pentavalente, y analizar el posible papel de estas proteínas en mecanismos de resistencia. Materiales y métodos. Las proteínas de las cepas, sensible y resistente al antimonio pentavalente, se compararon usando electroforesis bidimensional. Las proteínas con aumento de la expresión fueron aisladas e identificadas por espectrometría de masas mediante MALDI-TOF/TOF (Matrix Assisted Laser Desorption Ionization/Time of Flight). La expresión del ARNm de cinco de estas proteínas se cuantificó mediante PCR en tiempo real. Resultados. Los geles bidimensionales de las cepas sensible y resistente detectaron 532±39 y 541±43 manchas proteicas. Se encontraron 10 manchas con aumento de la expresión en la cepa resistente, identificadas como proteínas de choque térmico (Hsp60 mitocondrial, Hsp70 mitocondrial y citosólica), isomerasa de disulfuro, proteasa de cisteína, enolasa, factor de elongación 5-α, la subunidad 5-α del proteasoma y dos proteínas hipotéticas nombradas como Sp(2) y Sp(25). Conclusión. Este es el primer estudio llevado a cabo con una cepa resistente al antimonio pentavalente en L. panamensis, en el cual se han identificado proteínas que están relacionadas con el mecanismo de resistencia del parásito frente al medicamento, abriendo el camino para futuros estudios de estas proteínas como blancos terapéuticos.

Introduction. The well-known drug resistance mechanisms to pentavalent antimony have been widely described in strains of the Leishmania subgenus, but little is known about the mechanisms of resistance and the proteins associated with it in strains of the Viannia subgenus such as Leishmania panamensis. Objective. Differentially expressed proteins were identified between pentavalent antimonial sensitive and resistant L. panamensis (UA140) strains, and the role of these proteins was analyzed as possible resistance mechanisms. Materials and methods. The protein lysates of pentavalent antimony sensitive and resistant strains were separated by two-dimensional gel electrophoresis,and the protein patterns compared. The proteins identified as overexpressed were separated and analyzed using MALDI-TOF/TOF (Matrix Assisted Laser Desorption Ionization/Time of Flight). The level of mRNA expression of five of these proteins was quantified using real-time PCR. Results. On the 2-dimensional gels, 532 ± 39 protein spots were identified for the sensitive strains, and 541 ± 43 spots for the resistant strains. Ten spots were overexpressed in the resistant strain and identified as heat shock protein (Hsp60 mitochondrial, Hsp70 cytosolic and mitochondrial), disulfide isomerase, cysteine protease, enolase, elongation factor 5-alpha, the proteasome alpha-5 subunit and two hypothetical proteins named as Sp(2) and Sp(25). Conclusion. This is the first proteomic study conducted with a L. panamensis resistant strain where several proteins were identified and related with the parasite resistance mechanism to pentavalent antimony. This opens the way for future studies aimed at modulating the drug resistance or at evaluating these proteins as therapeutic targets.

Low-dose CT perfusion imaging based on pre-scan regulation and on reconstruction with sparsity constraints / 生物医学工程学杂志

The long-period CT perfusion imaging leads to an excess amount of radiation dose to the patient. However, the radiation dose could be significantly reduced if a previous normal-dose image is acquired before a set of low-dose scans of perfusion, and a filtering processing is performed on the differences between the current low-dose images and the previous normal-dose image, then the results are added to the previous image. But the selection of plenty of parameters makes the algorithm complicated. This paper proposes an innovative approach performed in sinogram domain instead of in image domain. First a normal-dose image and a set of low-dose projection data are acquired before the perfusion. Second the perfusion information is commendably reconstructed with sparsity constraints of the differences between current low-dose perfusion sinograms and previous low-dose sinogram. Finally, the reconstructed perfusion information is added to the previous normal-dose image. The proposed method was validated by simulated experiments with a set of brain CT perfusion images, which showed that the new method provided more accurate perfusion information; the time-attenuation curve was more close to that for normal-dose scan and the mean transit time more repeatable.

[Digital subtraction technique in studying the bone quality alterations around dental implants: a comparison study between linear and logarithmic subtraction images]

The aim was to evaluate the efficiency of the digital logarithmic subtraction method in assessing the alteration of bone density around the dental implants; comparison with the digital linear subtraction method. Forty dental implants were set in the posterior mandibles of 40 patients. A standard reference periapical digital Image [A] was taken one-week post-surgical. Three images [B1, B2 and B3] were taken 3 months later. These images were treated separately by digital linear and logarithmic subtractions using Emago advanced/5,3 software; so, 120 linear subtraction and 120 logarithmic subtraction images were obtained. A region of interest [ROI] was determined distal to each implant cervical area and radiographic bone density was obtained. The mean value of the total digital subtraction evaluated by logarithmic subtraction was significantly more compared to what was evaluated by linear subtraction [21.70 +/- 9.36 and 17.24 +/- 8.98 respectively; P<0.000], counter to the mean values of the total change of the digital subtraction [0.58 +/- 0.53 and 1.89 +/- 1.38 respectively; P<0.000] and the percentage of the total change of the digital subtraction [3.41 +/- 6.64 and 13.08 +/- 10.96 respectively; P<0.000] which were less. The digital logarithmic subtraction is a precise method in evaluating the alteration of the bone density.

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.

Digital subtraction radiographic analysis of the combination of bioabsorbable membrane and bovine morphogenetic protein pool in human periodontal infrabony defects

OBJECTIVES: This study assessed the bone density gain and its relationship with the periodontal clinical parameters in a case series of a regenerative therapy procedure. MATERIAL AND METHODS: Using a split-mouth study design, 10 pairs of infrabony defects from 15 patients were treated with a pool of bovine bone morphogenetic proteins associated with collagen membrane (test sites) or collagen membrane only (control sites). The periodontal healing was clinically and radiographically monitored for six months. Standardized pre-surgical and 6-month postoperative radiographs were digitized for digital subtraction analysis, which showed relative bone density gain in both groups of 0.034 ± 0.423 and 0.105 ± 0.423 in the test and control group, respectively (p>0.05). RESULTS: As regards the area size of bone density change, the influence of the therapy was detected in 2.5 mm² in the test group and 2 mm² in the control group (p>0.05). Additionally, no correlation was observed between the favorable clinical results and the bone density gain measured by digital subtraction radiography (p>0.05). CONCLUSIONS: The findings of this study suggest that the clinical benefit of the regenerative therapy observed did not come with significant bone density gains. Long-term evaluation may lead to a different conclusions.

Dual-Energy Subtraction Imaging for Diagnosing Vocal Cord Paralysis with Flat Panel Detector Radiography

OBJECTIVE: To investigate the clinical feasibility of dual energy subtraction (DES) imaging to improve the delineation of the vocal cord and diagnostic accuracy of vocal cord paralysis as compared with the anterior-posterior view of flat panel detector (FPD) neck radiography. MATERIALS AND METHODS: For 122 consecutive patients who underwent both a flexible laryngoscopy and conventional/DES FPD radiography, three blinded readers retrospectively graded the radiographs during phonation and inspiration on a scale of 1 (poor) to 5 (excellent) for the delineation of the vocal cord, and in consensus, reviewed the diagnostic accuracy of vocal cord paralysis employing the laryngoscopy as the reference. We compared vocal cord delineation scores and accuracy of vocal cord paralysis diagnosis by both conventional and DES techniques using kappa statistics and assessing the area under the receiver operating characteristic curve (AUC). RESULTS: Vocal cord delineation scores by DES (mean, 4.2 +/- 0.4) were significantly higher than those by conventional imaging (mean, 3.3 +/- 0.5) (p < 0.0001). Sensitivity for diagnosing vocal cord paralysis by the conventional technique was 25%, whereas the specificity was 94%. Sensitivity by DES was 75%, whereas the specificity was 96%. The diagnostic accuracy by DES was significantly superior (kappa = 0.60, AUC = 0.909) to that by conventional technique (kappa = 0.18, AUC = 0.852) (p = 0.038). CONCLUSION: Dual energy subtraction is a superior method compared to the conventional FPD radiography for delineating the vocal cord and accurately diagnosing vocal cord paralysis.

Influência das variações de ângulos de projeção na detecção de reabsorções radiculares linguais e apicais simuladas: comparação entre subtração radiográfica digital e radiografia digital direta / Influence of changing projection angle detection of root resorption apical and lingual simulated: comparison between subtraction digital radiography and direct digital radiography

A reabsorção severa da raiz diagnosticada tardiamente pode acarretar a perda dentaria, e sendo a técnica de subtração radiográfica digital (SDR) um importante recurso para detecção precoce de alterações minerais, este estudo avaliou a eficiência no diagnóstico precoce da reabsorção radicular externa simulada apical e lingual, pela técnica de subtração radiográfica digital (SRD) e radiografia digital (RD). Foram utilizados 14 dentes incisivos de mandíbulas humanas maceradas com reabsorções de diferentes dimensões, simuladas na região apical e lingual, e radiografados com variação de ângulos de projeção. As radiografias foram subtraídas pelo programa Regeemy®, e para avaliação do desempenho dos métodos de diagnóstico, pares de radiografias periapicais e imagens subtraídas foram apresentadas a 2 radiologistas. De acordo com os resultados, não foram observadas diferenças estatisticamente significativas entre os métodos na detecção de reabsorções linguais, independentemente do tamanho da lesão, assim como não houve diferença entre os métodos na detecção de reabsorções apicais, com exceção do examinador 2 com relação avariação angular vertical e horizontal de 100 utilizando o maior nível de desgaste, que apresentou a radiografia digital como método superior na avaliação em relação a subtração radiográfica. E o aumento no nível de desgastes e a menor variação dos ângulos verticais e horizontais permitiram melhor avaliação nas regiões de reabsorções apicais e linguais, para detecção das reabsorções apicais e linguais. Com estes resultados podemos concluir que a subtração radiográfica digital é um exame indicado para detecção de pequenas perdas minerais em radiografias que apresentem pouca ou nenhuma variação nas angulações verticais e horizontais.

The severe root resorption diagnosed late can lead to tooth loss, andbeing the technique of digital subtraction radiography (SDR) as animportant resource for early detection mineral changes, this studyevaluated the efficiency in the early diagnosis simulated external rootresorption apical and lingual by the technique of digital subtraction radiography (SRD) and digital radiography (DR). We used 14 human incisors jaw macerated with resorption different sizes, simulated in the apical and lingual, and radiographed with a range of projection angles.The radiographs were subtracted by the program Regeemy ®, andperformance evaluation diagnostic methods, pairs intraoral radiographs and subtracted images were presented to two radiologists. According tothe results, there were no statistically significant differences between methods in the detection lingual resorption, regardless of lesion size, as there was no difference between the methods in the detection of apical resorption, except the second examiner with respect to variation vertical and horizontal angle of 100 using the highest level of wear, which lodged the digital radiography as a method superior in the evaluation for subtraction radiography. And the increase in the level of wear and less variation vertical and horizontal angles allowed a better assessment resorption in the regions apical and lingual to detect and lingual apical resorption. With these results we conclude that the digital subtraction radiography is a test for the detection of small mineral loss in radiographs showing little or no variation in vertical and horizontal angles.

Avaliação dos implantes Nobel Direct por subtração radiográfica digital sob novo protocolo protético / Evaluation of Nobel Direct implants by digital subtraction radiography under new prosthetic protocol

O implante peça única Nobel Direct (Pund) foi preconizado para prevenir perda óssea alveolar marginal pela sua macrogeometria e por proporcionar ausência de microgap entre fixação e o componente protético. O objetivo deste estudo foi verificar através de subtração radiográfica digital de Punds submetidos à carga imediata sob novo protocolo protético. Inicialmente foram selecionados 20 implantes em 20 pacientes. O estudo seguiu avaliando oito implantes mensalmente durante os primeiros seis meses de osseointegração através de subtração digital (CDR-Shick - X-Poesit) realizada com radiografias padronizadas por placa oclusal personalizada. A média de quantidade de pixels relacionados à perda óssea (QPPO) foi 480,3 e a média de quantidade de pixels relacionados ao ganho ósseo (QPGO) foi 54,5 (p=0,011). A média de perda óssea vertical aferida pelo programa Image tool-3.0 foi de 1,04 mm durante os primeiros seis meses pós-instalação dos Pund. Concluiu-se que este sistema não previne perda óssea alveolar marginal, em especial nos primeiros seis meses pós-instalação. Porém, a partir da instalação das coroas definitivas, a remodelação óssea tende a diminuir, estabilizando a distância biológica estabelecida, com resultados semelhantes aos implantes convencionais de duas peças. Durante 40 meses de controle clínico não houve perdas e todos os 20 implantes obtiveram sucesso.

The Nobel Direct One-Piece Implant (Pund) has being recommended to prevent marginal bone resorption. The argument is that this system provides no implant-abutment microgap. The aim of this study was to verify this issue using Digital Subtraction Radiography at immediate loaded Punds according to a new prosthetic protocol. First, 20 implants were selected in 20 patients. Then, the study followed evaluating eight implants monthly during the first six months of osseointegration through digital subtraction (CDR-Shick - X-Poesit) performed with standardized radiographs by an individual oclusal index. The average pixels-related bone loss (QPPO) was 480.3 and the pixels gain related to increased bone (QPGO) was 54.5 (p=0.011). The mean vertical bone loss verified by Image tool - 3.0 Program was 1.04 mm during the first six months after Pund installation. It was concluded that this system does not prevent alveolar bone loss especially in the first six postoperative months. However, the bone turnover tends to decrease after delivery of definitive crowns, stabilizing the biological distance acquired, with results similar to conventional, two-piece implants. During 40 months no implant was lost and the 20 fixtures were considered successful.

Subtração radiográfica digital em Implantodontia / Digital subtraction radiography in implantology

A Subtração Radiográfica Digital (SRD) é uma técnica consagrada na área de Periodontia por apresentar altas taxas de sensibilidade e especificidade. Diante disso, a SRD apresentou aplicabilidade em implantodontia, pois para a avaliação do sucesso ou falência de implantes, além dos parâmetros clínicos também é utilizado o exame radiográfico, o qual possui inúmeras limitações. Sendo assim, o presente trabalho ao revisar a literatura se propõe a expor a técnica de SRD e sua aplicabilidade em pesquisas e na clínica diária, exclusivamente em implantodontia. Na literatura se verifica a SRD como uma técnica capaz de calcular o volume de lesões periimplantares, detectar perdas ósseas, avaliar os efeitos das terapias antimicrobianas no tratamento das periimplantites, monitorar a osseointegração dos implantes e dos enxertos ósseos e averiguar a reação do tecido ósseo diante diversos tipos de cargas oclusais. No entanto, ainda não foram desenvolvidos sistemas de padronização das tomadas radiográficas, além de programas de computador e alinhamento das imagens que viabilizem a aplicabilidade clínica da SRD. Dessa forma, apresente técnica se restringe ao ambiente de pesquisa, no qual de forma criteriosa, é possível obter informações importantes para auxiliar a tomada de decisão clínica.

It has been previously shown that the Digital Subtraction Radiography (DSR) is an excellent technique used in periodontology because the higher levels of sensitivity and specificity. Therefore, the DSR has also presented applicability in implantology to evaluate the success or failure of the dental implant, beside the clinical parameters (probing depth, clinical attachment level, mobility, suppuration) and conventional radiographic parameters, which one has some limits. Soon, the propose of this review was show the SRD tecnique and its applicability in research and dental office, exclusively in implantology. The literature shows that the DSR can estimate the volume of alveolar bone lesions caused by periimplantitis, to evaluate the efficacy of antimicrobial and regenerative (GTR) therapies, to follow the success of dental implants and bonegrafts osseointegration and to study the different types of loading on bone. However, it’s not been developed accurated sistems to take identical radiographics, as soon as computer softwares wich make DSR feaseble at side chair. Therefore, this technique can only be used for research reasons, in wich rigorous requirements for its use may help on the sidechair decision-makings.

Avaliação da eficiência de dois programas na eliminação de ruído para técnica de subtração / Comparison between two programs of image register for subtract ion technique

O objetivo neste trabalho foi comparar, por meio da técnica de subtração radiográfica digital (SRD), a qualidade do registro a posteriori de 2 programas de computador. Para isso foi utilizada amostra de 294 radiografias periapicais digitais diretas. Essa amostra foi obtida de estudo anterior, no qual foram radiografados 49 dentes de mandíbulas maceradas, das regiões de incisivos centrais, laterais, caninos e pré molares. Cada dente foi radiografado com 6 diferentes ângulos de projeção, sendo: 0° de ângulo horizontal com 0°, 10° e 20° de ângulo vertical, e 10° de ângulo horizontal com 0°, 10° e 20° de ângulo vertical. As imagens radiográficas foram inseridas nos programas EMAGO® e Regeemy para os registros. Em seguida as SRD foram realizadas no programa Image Tool versão 1.27. A qualidade do registro das imagens foi avaliada por meio dos valores do desvio-padrão (DP) dos níveis de cinza das imagens subtraídas, o (DP) dos níveis de cinza serve como parâmetro para determinar o ruído nas imagens subtraídas. Para isso foi utilizado o programa Adobe Photoshop versão 7.0. A comparação dos valores do ruído das imagens subtraídas (desvio-padrão dos níveis de cinza) foi realizada pelo teste t pareado com nível de significância de 5%. Pelos resultados, verificou-se diferença estatisticamente significantes entre os 2 programas para todas as variações de ângulos de projeção estudadas, com valores maiores no DP quando se utilizou o programa EMAGO®. Visto que as imagens registradas pelo programa Regeemy resultaram em imagens subtraídas com menor desvio padrão de tons de cinza, conclui-se que esse programa apresentou melhor performance no registros de imagens para a técnica de subtração.

The aim of this study was to compare the quality of image registration of two computer programs by means of digital subtraction radiography(DSR). The sample comprised 294 direct digital periapical radiographs.This sample was obtained from a previous study in which 49 mandibularteeth (central incisors, laterals incisors, cuspids and bicuspids), wereradiographed with 6 different x-ray beam angles: 0° horizontal with 0°, 10°and 20° vertical, and 10° horizontal with 0°, 10° and 20° vertical. The radiographs were registered with EMAGO and Regeemy. The registered images were subtracted from their respective reference images with Image Tool 1.27. The quality of the registered images was evaluated by the mean values of the standard deviation (SD) of gray levels on the subtracted images, using the histogram tool of Adobe Photoshop 7.0. Paired t-testwas adopted to compare the mean SD for the gray levels between Reegemy and Emago. The results demonstrated statistically significant differences on the quality of image registrations of the programs for allvariations of angle. Higher SD was found for the subtractions obtained with registered images of EMAGO®. The SD for gray levels is the usual parameter for evaluation of image noise on subtracted images. Sincelower SD was observed for the gray levels of subtractions obtained with registered images from Reegemy, we concluded that Regeemy achieved better performance on image registration for the subtraction techinique.

Avaliação de reabsorções radiculares externas por meio de reconstrução digital de imagens e subtração radiográfica digital / Assessment of external root resorptions using digital reconstruction and digital subtraction radiography

Diante dos prejuízos que a reabsorção severa da raiz pode acarretar, e considerando a técnica de subtração radiográfica digital (SDR) importante recurso para detecção precoce de alterações minerais, propõe-se neste estudo avaliar a eficiência de um programa de computador, que execute o registro das imagens e SRD, no diagnóstico da reabsorção radicular externa simulada, comparado à radiografia digital, além da concordância intra e interexaminadores nos 2 métodos de diagnóstico. Os 49 dentes de mandíbulas humanas maceradas com reabsorções de diferentes dimensões, simuladas na região apical e lingual, foram radiografados com variação de ângulos de projeção. A radiografias foram registradas a posteriori pelo programa Regeemy® e subtraídas pelo programa Image Tool®. A quantidade de ruído estrutural nas imagens subtraídas foi obtida pela mensuração da média e desvio-padrão dos níveis de cinza. Para avaliação do desempenho dos métodos de diagnóstico, pares de radiografias periapicais e imagens subtraídas foram apresentadas a 3 radiologistas. De acordo com os resultados, o ruído das imagens subtraídas de radiografias após variações de 10º e 20º do ângulo vertical e 10º horizontal e corrigidas a posteriori, foi significantemente maior que das imagens subtraídas de radiografias padrão, independente da região radiografada. Não houve diferença estatisticamente significativa entre os métodos na detecção de reabsorções apicais, independentemente do tamanho da lesão, assim como não houve diferença entre os métodos na detecção de reabsorções linguais de 1,2mm ou mais. A SRD foi significantemente superior à radiografia digital para detecção de lesões linguais de cerca de 1 mm. Cavidades na superfície lingual de cerca de 0,5 mm não foram detectadas com precisão por nenhum dos métodos. A concordância intra e interexaminadores na interpretação das reabsorções foi substancial ou quase perfeita em ambos os métodos, sendo maior quando se utilizava a SRD.