RESUMO
Magnetic resonance images of rat brain were analyzed by texture analysis in order to study the effects of a nociceptive stimulation (formalin test) under propofol deep anesthesia. Changes of the texture in different cerebral brain areas acquired before and after stimulation were checked. Our statistical analysis of texture shows that these changes were present only in the amygdala, in agreement with the facts already known about the unconscious memorization of nociceptive stimuli.
Assuntos
Tonsila do Cerebelo/anatomia & histologia , Tonsila do Cerebelo/fisiologia , Encéfalo/anatomia & histologia , Encéfalo/fisiologia , Imageamento por Ressonância Magnética/métodos , Tonsila do Cerebelo/efeitos dos fármacos , Anestesia , Animais , Encéfalo/efeitos dos fármacos , Formaldeído , Nociceptores/efeitos dos fármacos , Nociceptores/fisiologia , Medição da Dor , Propofol , Ratos , Ratos Sprague-DawleyRESUMO
The purpose of this study was to perform serial texture analysis of brain MRI of cuprizone-treated mice for the assessment of regional demyelination and remyelination. Cuprizone-fed mice undergo a brain demyelination process. This process was followed over 56 days by MRI in the olfactory bulbs, cerebellum, putamen and brain stem. The texture of T2-weighted images has been analyzed at two levels: (1) with the average intensity as first order parameter and (2) with several higher order parameters for the best differentiation between myelinated (controls) and demyelinated brains. The most pertinent of these parameters, called horizontal gray level nonuniformity (HGLNU), has been selected by stepwise discriminant analysis. The time evolution of the average value of HGLNU not only confirmed the overall demyelination tendency followed by the average intensity, but also more precisely characterized a transitory remyelination on day 41 in the olfactory bulbs and cerebellum, in agreement with already published immunohistochemical destructive studies.
