Validation of Dementia Models Employing Neuroimaging Techniques

Dementia is a clinical diagnosis; however, none of the clinical scales guarantee high sensitivity or specificity. Therefore, neuroimaging is often crucial for proper assessment. The most typical neurological symptoms of dementia are often discerned using computed X-ray tomography (CT), magnetic resonance imaging (MRI), magnetic resonance spectroscopy (MRS), single-photon emission computerized tomography (SPECT), and positron-emission tomography (PET) techniques. In general, these different imaging modalities provide different information and can be considered as being complementary rather than competitive. Nowadays, structural neuroimaging is a routine component of the diagnostic evaluation of dementia. Neuroimaging offers promise as a surrogate marker for clinical trials, and new technologies have been developed to provide more molecular and physiological biomarkers such as markers for amyloid plaques, one of the neuropathological hallmarks of AD. The combined use of imaging technology and experimental in vivo animal models for human diseases provides a unique platform to study pathological mechanisms in longitudinal studies, develop accurate and early translational diagnostic tools, and evaluate therapeutic strategies. In this chapter, an overview of how brain imaging can be used to detect both early and late stages of dementia in small animal models is explained. The early stage offers a unique therapeutic window and is diagnostically most challenging.