Brain neuroimaging of domestic cats: correlation between computed tomography and cross-sectional anatomy / Neuroimagem cerebral de gatos domésticos: correlação entre a tomografia computadorizada e a anatomia seccional

Computed tomography of the brain is necessary as part of the diagnosis of lesions of the central nervous system. In this study we used six domestic cats, male or female, aged between one and five years, evaluated by Computed Tomography (CT) examination without clinical signs of central nervous system disorders. Two euthanized animals stating a condition unrelated to the nervous system were incorporated into this study. The proposal consisted in establishing detailed anatomical description of tomographic images of normal brain of cats, using as reference anatomical images of cross sections of the stained brain and cranial part, with thicknesses similar to the planes of the CT images. CT examinations were performed with and without intravenous iodinated contrast media for live animals. With one euthanized animal, the brain was removed and immediately preserved in 10% formalin for later achievement in cross-sectional thickness of approximately 4mm and staining technique of Barnard, and Robert Brown. The head of another animal was disarticulated in the Atlanto-occipital region and frozen at -20ºC then sliced to a thickness of about 5mm. The description of visualized anatomical structures using tomography is useful as a guide and allows transcribing with relative accuracy the brain region affected by an injury, and thus correlating it with the clinical symptoms of the patient, providing additional information and consequent improvement to veterinarians during the course of surgical clinic in this species.(AU)

A tomografia computadorizada do cérebro é de suma importância como parte do diagnóstico de lesões do sistema nervoso central. Neste estudo, foram utilizados seis felinos domésticos, machos ou fêmeas, com idade entre um e cinco anos, avaliados pela tomografia computadorizada (TC), sem sinais clínicos de distúrbios do sistema nervoso central. Dois cadáveres indicando a condição relacionada com o sistema nervoso foram incorporados ao presente estudo. A proposta consistiu na criação da descrição anatômica detalhada das imagens tomográficas de cérebro normal de gatos, usando como referência a imagens anatômicas de secções transversais do cérebro coradas, realizadas com espessuras similares aos planos das imagens tomográficas. Exames de TC foram realizados com e sem contraste iodado intravenoso para os animais vivos. Em um dos cadáveres, o cérebro foi removido e imediatamente preservado em formalina a 10% para a realização posterior da técnica de coloração de Barnard e Robert Brown, além de cortes transversais com espessura de, aproximadamente, 4mm. O crânio do outro cadáver foi desarticulado na região atlanto-occipital e congelado a -20ºC. Em seguida, foi realizado corte com espessura de cerca de 5mm. A descrição das estruturas anatômicas visualizadas foi útil e serve como guia, permitindo descrever com relativa precisão a estrutura cerebral normal ou lesionada, e, portanto, correlacionando-a com os sintomas clínicos de um paciente, o que fornece informações adicionais e consequente aprimoramento de veterinários no curso de clínica cirúrgica para essa espécie.(AU)

Clinical applications and characteristics of apparent diffusion coefficient maps for the brain of two dogs

Diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) mapping are functional magnetic resonance imaging techniques for detecting water diffusion. DWI and the ADC map were performed for intracranial lesions in two dogs. In necrotizing leukoencephalitis, cavitated lesions contained a hypointense center with a hyperintense periphery on DWI, and hyperintense signals on the ADC maps. In metastatic sarcoma, masses including a necrotic region were hypointense with DWI, and hyperintense on the ADC map with hyperintense perilesional edema on DWI and ADC map. Since DWI and ADC data reflect the altered water diffusion, they can provide additional information at the molecular level.