RESUMO
The use of routine magnetic resonance imaging (MRI) to potentially assess skeletal fragility has been widely studied in osteoporosis. The aim of this study was to evaluate bone texture attributes (TA) from routine lumbar spine (LS) MRI and their correlation with vertebral fragility fractures (VFF) and bone mineral density (BMD). Sixty-four post-menopausal women were submitted to LS densitometry, total spine radiographs, and routine T2-weighted LS MRI. Twenty-two TA were extracted with the platform IBEX from L3 vertebra. The statistical difference was evaluated using ANOVA and Duncan's post-test. Correlation analyses were performed using Spearman's coefficient. Statistical significance was considered when P<0.05. The results did not show a significant difference in BMD between the women with and without fractures. Two bone TA (cluster tendency and variance) were significantly lower in the fracture group. Cluster tendency with VFF in osteopenia was 1.54±1.37 and in osteoporosis was 1.11±58. Cluster tendency without VFF in osteopenia was 2.23±1.38 and in osteoporosis was 1.88±1.14). Variance with VFF in osteopenia was 1.44±1.37 and in osteoporosis was 1.13±59. Variance without VFF in osteopenia was 2.34±1.38 and in osteoporosis was 1.89±1.14. There was a significant correlation between BMD and cluster prominence (r=0.409), cluster tendency (r=0.345), correlation (r=0.570), entropy (r=0.364), information measure corr1 (r=0.378), inverse variance (r=0.449), sum entropy (r=0.320), variance (r=0.338), sum average (r=-0.274), and sum variance (r=-0.266). Our results demonstrated the potential use of TA extracted from routine MRI as a biomarker to assess osteoporosis and identify the tendency of skeletal fragility vertebral fractures.
Assuntos
Doenças Ósseas Metabólicas , Osteoporose , Humanos , Feminino , Densidade Óssea , Vértebras Lombares/diagnóstico por imagem , Osteoporose/diagnóstico por imagem , Imageamento por Ressonância MagnéticaRESUMO
The use of routine magnetic resonance imaging (MRI) to potentially assess skeletal fragility has been widely studied in osteoporosis. The aim of this study was to evaluate bone texture attributes (TA) from routine lumbar spine (LS) MRI and their correlation with vertebral fragility fractures (VFF) and bone mineral density (BMD). Sixty-four post-menopausal women were submitted to LS densitometry, total spine radiographs, and routine T2-weighted LS MRI. Twenty-two TA were extracted with the platform IBEX from L3 vertebra. The statistical difference was evaluated using ANOVA and Duncan's post-test. Correlation analyses were performed using Spearman's coefficient. Statistical significance was considered when P<0.05. The results did not show a significant difference in BMD between the women with and without fractures. Two bone TA (cluster tendency and variance) were significantly lower in the fracture group. Cluster tendency with VFF in osteopenia was 1.54±1.37 and in osteoporosis was 1.11±58. Cluster tendency without VFF in osteopenia was 2.23±1.38 and in osteoporosis was 1.88±1.14). Variance with VFF in osteopenia was 1.44±1.37 and in osteoporosis was 1.13±59. Variance without VFF in osteopenia was 2.34±1.38 and in osteoporosis was 1.89±1.14. There was a significant correlation between BMD and cluster prominence (r=0.409), cluster tendency (r=0.345), correlation (r=0.570), entropy (r=0.364), information measure corr1 (r=0.378), inverse variance (r=0.449), sum entropy (r=0.320), variance (r=0.338), sum average (r=-0.274), and sum variance (r=-0.266). Our results demonstrated the potential use of TA extracted from routine MRI as a biomarker to assess osteoporosis and identify the tendency of skeletal fragility vertebral fractures.
RESUMO
The aims of this study were to evaluate the intra- and interobserver reproducibility of manual segmentation of bone sarcomas in magnetic resonance imaging (MRI) studies and to compare manual and semiautomatic segmentation methods. This retrospective study included twelve osteosarcoma and eight Ewing sarcoma MRI studies performed prior to any therapeutic intervention. All cases were histopathologically confirmed. Three radiologists used 3D-Slicer software to perform manual segmentation of bone sarcomas in a blinded and independent manner. One radiologist segmented manually and also performed semiautomatic segmentation with the GrowCut tool. Segmentation exercises were timed for comparison. The dice similarity coefficient (DSC) and Hausdorff distance (HD) were used to evaluate similarity between the segmentation results and further statistical analyses were performed to compare DSC, HD, and volumetric results. Manual segmentation was reproducible with intraobserver DSC varying from 0.83 to 0.97 and HD from 3.37 to 28.73 mm. Interobserver DSC of manual segmentation showed variation from 0.73 to 0.97 and HD from 3.93 to 33.40 mm. Semiautomatic segmentation compared to manual segmentation resulted in DSCs of 0.71-0.96 and HDs of 5.38-31.54 mm. Semiautomatic segmentation required significantly less time compared to manual segmentation (P value ≤0.05). Among all situations compared, tumor volumetry did not show significant statistical differences (P value >0.05). We found excellent intra- and interobserver agreement for manual segmentation of osteosarcoma and Ewing sarcoma. There was high similarity between manual and semiautomatic segmentation, with a significant reduction of segmentation time using the semiautomatic method.
Assuntos
Neoplasias Ósseas/diagnóstico por imagem , Osteossarcoma/diagnóstico por imagem , Sarcoma de Ewing/diagnóstico por imagem , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Variações Dependentes do Observador , Reprodutibilidade dos Testes , Estudos Retrospectivos , Adulto JovemRESUMO
The aims of this study were to evaluate the intra- and interobserver reproducibility of manual segmentation of bone sarcomas in magnetic resonance imaging (MRI) studies and to compare manual and semiautomatic segmentation methods. This retrospective study included twelve osteosarcoma and eight Ewing sarcoma MRI studies performed prior to any therapeutic intervention. All cases were histopathologically confirmed. Three radiologists used 3D-Slicer software to perform manual segmentation of bone sarcomas in a blinded and independent manner. One radiologist segmented manually and also performed semiautomatic segmentation with the GrowCut tool. Segmentation exercises were timed for comparison. The dice similarity coefficient (DSC) and Hausdorff distance (HD) were used to evaluate similarity between the segmentation results and further statistical analyses were performed to compare DSC, HD, and volumetric results. Manual segmentation was reproducible with intraobserver DSC varying from 0.83 to 0.97 and HD from 3.37 to 28.73 mm. Interobserver DSC of manual segmentation showed variation from 0.73 to 0.97 and HD from 3.93 to 33.40 mm. Semiautomatic segmentation compared to manual segmentation resulted in DSCs of 0.71−0.96 and HDs of 5.38−31.54 mm. Semiautomatic segmentation required significantly less time compared to manual segmentation (P value ≤0.05). Among all situations compared, tumor volumetry did not show significant statistical differences (P value >0.05). We found excellent intra- and interobserver agreement for manual segmentation of osteosarcoma and Ewing sarcoma. There was high similarity between manual and semiautomatic segmentation, with a significant reduction of segmentation time using the semiautomatic method.
Assuntos
Humanos , Masculino , Feminino , Pré-Escolar , Criança , Adolescente , Adulto , Adulto Jovem , Sarcoma de Ewing/diagnóstico por imagem , Neoplasias Ósseas/diagnóstico por imagem , Osteossarcoma/diagnóstico por imagem , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Variações Dependentes do Observador , Reprodutibilidade dos Testes , Estudos RetrospectivosRESUMO
Este trabalho descreve o desenvolvimento de um método que classifica de forma semi-automática a degeneração de discos intervertebrais lombares em imagens de ressonância magnética ponderadas em T2. O conjunto de imagens consiste de 210 discos extraídos de exames de 94 indivíduos (20 a 80 anos). A classificação é feita por uma rede neural do tipo perceptron multicamada com 6 entradas, 15 neurônios na camada intermediária e 1 saída. Os resultados obtidos mostraram uma taxa média de acerto de 81,42%, com erro padrão de 9,11%.
This article describes the development of a method that classifies semi-automatic degeneration of lumbar intervertebral discs in magnetic resonance T2-weighted images. The dataset consists of images of 210 discs obtained from94 individuals (20 to 80 year old). An artificial neural network of the multilayer perceptron with 6 inputs, 15 neuronsin the hidden layer and 1 output, was used to check the efficiency of this study. Obtained an average rate of sucess of81.42%, with a standard error of 9.11%.
Assuntos
Humanos , Imageamento por Ressonância Magnética , Degeneração do Disco Intervertebral/classificação , Pesos e Medidas , Congressos como AssuntoRESUMO
The superposition of medical images, technically known as co-registration, can take a major role in determining the topographic and morphological changes in functional diagnostic and therapeutic purposes. This paper describes a study focused on to find an alternative cost function method for medical images co-registration through the study of performance and robustness of the TSallis Entropy in Statistical Parametric Mapping package (SPM). Images of Magnetic Resonance (MR) and Single Photon Emission Computed Tomography (SPECT) of 3 patients morphologically normal were used for the construction of anatomic phantoms containing predetermined geometric variations. The simulated images were co-registered with the original images using traditional techniques and the proposed method. The comparative analysis of the Root Mean Square (RMS) error showed that the Tsallis Entropy was more efficient in the intramodality alignment, while the Shannon Entropy in the intermodality one; revealing therefore the importance of the implementation of the Tsallis Entropy in SPM for applications in neurology and neuropsychiatric evaluation.
Assuntos
Algoritmos , Imageamento por Ressonância Magnética/métodos , Tomografia Computadorizada de Emissão de Fóton Único/métodos , Encéfalo/patologia , HumanosRESUMO
In this paper, methods are presented for automatic detection of the nipple and the pectoral muscle edge in mammograms via image processing in the Radon domain. Radon-domain information was used for the detection of straight-line candidates with high gradient. The longest straight-line candidate was used to identify the pectoral muscle edge. The nipple was detected as the convergence point of breast tissue components, indicated by the largest response in the Radon domain. Percentages of false-positive (FP) and false-negative (FN) areas were determined by comparing the areas of the pectoral muscle regions delimited manually by a radiologist and by the proposed method applied to 540 mediolateral-oblique (MLO) mammographic images. The average FP and FN were 8.99% and 9.13%, respectively. In the detection of the nipple, an average error of 7.4 mm was obtained with reference to the nipple as identified by a radiologist on 1,080 mammographic images (540 MLO and 540 craniocaudal views).
Assuntos
Mamografia/métodos , Mamilos/diagnóstico por imagem , Músculos Peitorais/diagnóstico por imagem , Interpretação de Imagem Radiográfica Assistida por Computador , Reações Falso-Negativas , Reações Falso-Positivas , Feminino , Humanos , Reprodutibilidade dos TestesRESUMO
Cytokines play a fundamental role during development of the nervous system. In this work we demonstrate the effect of IL-2 and IL-4 on [(3)H]choline uptake by retinal cells in vitro. Treatments with both interleukins induced a twofold increase on [(3)H]choline uptake. This effect was dose- and time-dependent and inhibited by specific antibodies as well as by inhibition either of protein kinase C or tyrosine kinase activity or of the cytoplasmatic calcium level increase. A synergistic effect was obtained with low concentration of IL-2 (5 U ml(-1)) and IL-4 (0.5 U ml(-1)). However, high concentrations of IL-2 (50 U ml(-1)) and IL-4 (5 U ml(-1)) elicited an antagonistic effect. Our data indicate an important role for interleukins during retinal development.
Assuntos
Ácido Egtázico/análogos & derivados , Interleucina-2/farmacologia , Interleucina-4/farmacologia , Retina/citologia , Animais , Anticorpos/farmacologia , Cálcio/metabolismo , Células Cultivadas , Quelantes/farmacologia , Colina/farmacocinética , Colinérgicos/farmacologia , Relação Dose-Resposta a Droga , Sinergismo Farmacológico , Ácido Egtázico/farmacologia , Inibidores Enzimáticos/farmacologia , Genisteína/farmacologia , Hemicolínio 3/farmacologia , Interleucina-2/imunologia , Interleucina-4/imunologia , Testes de Neutralização , Proteína Quinase C/metabolismo , Proteínas Tirosina Quinases/metabolismo , Ratos , Ratos Endogâmicos , Retina/efeitos dos fármacos , Retina/enzimologia , TrítioRESUMO
The present report describes a computer tool for the coregistration of single-positron emission computed tomography (SPECT) and magnetic resonance (MR) images to aid the diagnosis. Two types of images are used for some neurologic diseases: one of them anatomic (magnetic resonance) and the other metabolic (SPECT), with the specialist being required to make a mental integration of the examinations. This procedure can be improved by using a computer tool that might permit the presentation of this information in a single image. The coregistration is performed on the basis of pairs of points positioned by a specialist according to the structures present in the images and the least squares error is calculated between them using Euclidean distance. Coinciding planes and section thickness are selected for the two modalities and the SPECT image is processed so as to have the same spatial resolution as the resonance image.
Assuntos
Encéfalo/anatomia & histologia , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Tomografia Computadorizada de Emissão de Fóton Único , Encéfalo/fisiologia , Metabolismo Energético/fisiologia , Humanos , Aumento da Imagem , Microcomputadores , SoftwareRESUMO
Cytokines are essential molecules throughout the development of the nervous system and also play an important role during the adult life span. In the present work, we analyzed in vitro the effect of spleen-cell-conditioned medium (SCM) on the survival and [3H]-choline uptake of neonatal rat retinal cells. SCM induced an increase in neuronal survival, glial cell proliferation and neurite outgrowth, as evaluated by biochemical and morphological criteria. These effects were time dependent; after 120 h, SCM induced a 6-fold increase in the total protein level. The effect of SCM was blocked both by the inhibition of protein tyrosine kinase activity (10 microM genistein) and by the inhibition of cell division (20 microM fluorodeoxyuridine). SCM also increased the uptake of [3H]-choline by retinal cells. The effect was time dependent. The maximum effect was obtained after 48 h and was maintained at a high level until 120 h. Treatment by 10 microM genistein and 15 microM bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA-AM) (an intracellular calcium chelator) completely blocked this effect. However, 20 microM fluorodeoxyuridine did not abolish it. Conditioned medium obtained from glial cells stimulated with SCM (S-GCM) induced an effect on [3H]-choline uptake earlier than that promoted by SCM. Anti-interleukin-2 (IL-2) antibodies blocked the effect of both SCM and S-GCM on [3H]-choline uptake after 48 and 72 h. IL-2 (50 U/ml) elicited the same effect as that observed when the cells were maintained in the presence of SCM. Taken together, our results suggest that IL-2 plays an important role in controlling the survival and differentiation of retinal cells in vitro.
Assuntos
Colina/metabolismo , Meios de Cultivo Condicionados/farmacologia , Interleucina-2/fisiologia , Retina/imunologia , Retina/metabolismo , Baço/citologia , Baço/imunologia , Animais , Diferenciação Celular/imunologia , Sobrevivência Celular/imunologia , Células Cultivadas , Ativação Linfocitária , Neuroglia/imunologia , Neuroglia/metabolismo , Ratos , Retina/citologia , Baço/metabolismo , TrítioRESUMO
Este trabalho apresenta um estudo comparativo de dois métodos de substração de angiografias determinando as vantagens e desvantagens de cada um em relação ao ruido das imagens.
Assuntos
Angiografia , Meios de Contraste/efeitos da radiação , Monitoramento do Ruído , Vasos Sanguíneos , AlgoritmosRESUMO
In this paper, it is demonstrated that obtaining OTF's for only two directions, parallel and perpendicular to the x-ray tube axis, is insufficient to completely describe the performance of nonisotropic radiographic systems. By performing experiments with three radiological systems in which slit images were obtained for ten different directions, we confirmed that OTF's vary in a nonlinear fashion for directions that are intermediate to the parallel and perpendicular ones. Moreover, we have also identified for each system a range of field orientations--referred to as "Optimum Region"--where sharper images can be obtained. These experimental results can be accounted for by the transfer functions theory.