RESUMO
Recent developments in high-resolution MR imaging techniques have opened up new perspectives for structural characterization of trabecular bone by non-invasive methods. In this study, 3-D MR imaging was performed on 17 healthy volunteers and 6 osteoporotic patients. Two different MR sequences were used to evaluate the impact on MR acquisition on texture analysis results. Images were analyzed with four automated methods of texture analysis (grey level histogram, cooccurrence, runlength and gradient matrices) enabling quantitative analysis of grey level intensity and distribution within three different regions of interest (ROI). Texture analysis is not very frequently used since the interpretation of the large number of calculated parameters is difficult. We applied multiparametric data analyses such as principal component analysis (CFA) and hierarchical ascending classification (HAC) to determine the relevant parameters to differentiate between three sets of images (healthy young volunteers, healthy postmenopaused and osteoporotic patients). The results suggest that relevant texture information (depending on the ROI localization in the calcaneus) can be extracted from calcaneus MR images to evaluate osteoporosis and age effects on trabecular bone structure if strictly the same acquisition sequences are used for all patients' examination.
Assuntos
Calcâneo/patologia , Imageamento por Ressonância Magnética/métodos , Osteoporose Pós-Menopausa/diagnóstico , Adulto , Idoso , Envelhecimento/patologia , Calcâneo/anatomia & histologia , Feminino , Humanos , Processamento de Imagem Assistida por Computador/métodos , Pessoa de Meia-Idade , Sensibilidade e EspecificidadeRESUMO
The olfactory bulbectomized (OB) rat is a well-accepted animal model of depression. The present magnetic resonance imaging (MRI) investigation demonstrates alterations in signal intensities in cortical, hippocampal, caudate and amygdaloid regions in OB animals, but not in sham operated controls. Ventricular enlargement was also evident in OB animals. These alterations have implications with regard to the face and construct validity of this model.
Assuntos
Encéfalo/fisiopatologia , Depressão/fisiopatologia , Bulbo Olfatório/fisiologia , Tonsila do Cerebelo/fisiologia , Tonsila do Cerebelo/fisiopatologia , Animais , Encéfalo/fisiologia , Núcleo Caudado/fisiologia , Núcleo Caudado/fisiopatologia , Córtex Cerebral/fisiologia , Córtex Cerebral/fisiopatologia , Ventrículos Cerebrais/fisiologia , Ventrículos Cerebrais/fisiopatologia , Modelos Animais de Doenças , Hipocampo/fisiologia , Hipocampo/fisiopatologia , Imageamento por Ressonância Magnética , Ratos , Valores de ReferênciaRESUMO
Automated magnetic resonance imaging (MRI) texture analysis was compared with visual MRI analysis for the diagnosis of skeletal muscle dystrophy in 14 healthy and 17 diseased subjects. MRI texture analysis was performed on 8 muscle regions of interest (ROI) using four statistical methods (histogram, co-occurrence matrix, gradient matrix, runlength matrix) and one structural (mathematical morphology) method. Nine senior radiologists assessed full leg transverse slice images and proposed a diagnosis. The 59 extracted texture parameters for each ROI were statistically analyzed by Correspondence Factorial Analysis. Non-parametric tests were used to compare diagnoses based on automated texture analysis and visual analysis. Texture analysis methods discriminated between healthy volunteers and patients with a sensitivity of 70%, and a specificity of 86%. Comparison with visual analysis of MR images suggests that texture analysis can provide useful information contributing to the diagnosis of skeletal muscle disease.