Application of Coregistration for Imaging of Animal Models of Epilepsy

Abstract

Summary:The past decade has seen a surge in the utilization of small animal imaging for epilepsy research. In vivo imaging studies have the potential to provide important insights into the structural and functional correlates of the development and progression of epilepsy in these models. However, the small size of the rodent brain means that anatomic resolution is often relatively poor for many imaging modalities, particularly those providing functional information such as positron emission tomography. Coregistration of these images with those of higher structural resolution, such as MRI, provides an attractive approach to this problem, and also allows correlations between structural and functional imaging data. Image coregistration is commonly utilized in clinical research and practice. However, its application for small animal images has been, to date, relatively under utilized and largely unvalidated. The current review aims to provide an overview of image coregistration methods, particularly for MRI and PET, and their application to imaging of small animal models of epilepsy. Methodological advantages and potential traps are highlighted. Key Words: MRI-PETImage coregistration-Small animal models of epilepsy-Brain imaging.Neuroimaging provides powerful diagnostic and research tools for the in vivo detection of structural and functional changes in the brain in patients with epilepsy. It is now an essential component of the clinical evaluation of patients with epilepsy for the localization of epileptic foci as well as for the identification of regions of eloquent cortex. Its use in clinical research to investigate the pathophysiological, functional, and structural correlates of chronic epilepsy and the process of epileptogenesis is also well established. The increasing use of multimodality imaging acquisition has seen techniques for coregistration, where two or more images are mathematically transformed into the same three-dimensional space, become routinely employed in both the clinical and research setting. Coregistration offers the ability to directly correlate the information provided by each of the scans, maximizing the usefulness of the acquired information. This is most commonly applied to register a type of image with lower structural information, such as positron emission tomography (PET), with one with higher structural detail, such as magnetic resonance imaging (MRI). In this setting, coregistration can be an important method for de- termining accurate anatomical localizations of changes on functional imaging, including for the placement of regions of interest (ROIs) for the quantification of changes within specific brain structures or for image-guided surgical interventions. Animal models of epilepsy have a long and productive history in epilepsy research. Neuroimaging of animal models of epilepsy is a relatively new approach to the study of the structural and functional changes associated with epileptogenesis, chronic epilepsy, and the effect of seizures. Neuroimaging has the important advantage o...

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