FDG PET and cognitive symptoms of dementia

The fundamentals of FDG PET are well established, and are based on extensively explored molecular mechanisms. The existing methods for semi-quantitative assessment of brain functional changes provide topographical maps of molecular alterations both for group and single-subject comparisons. This functional brain-based approach to derangement of high-order cognition has provided and will continue to provide high-quality findings that will help further understanding of brain cognitive activity and of the brain-cognition correlates and their importance in the diagnosis of the underlying pathology. This article examines the relationship between changes in brain metabolic activity and the resulting impairment of high-order cognition in dementia conditions. FDG PET imaging in subjects with underlying neurodegenerative pathology has emerged as a crucial tool available to the fields of cognitive neurology and neuroscience for both diagnosis and evaluation of the involved neural systems, extending the neuropsychology-based understanding of the brain/cognition relationship. As an effect of the multiple underlying pathologies, the cognitive deficits encountered encompass different aspects of neuropsychology: language, memory, performance monitoring, decision making, reasoning, and even "personality." It is to be noted that FDG PET studies of brain cognitive reserve have so far supported the existence of functional reserve phenomena in neurodegenerative dementia, and specifically in AD. The newly integrated PET/MRI techniques will likely become crucial clinical and research tools in neurology, nuclear medicine and in the neuroscience field generally. Hybrid PET/MRI will allow integration of the molecular information provided by PET with the various morphological and functional parameters measured by MRI, in the same subject and in a single study session. Future progress depends on exploration of these relationships to pave the way for new insights into neuroscience and neurology. © 2013 Italian Association of Nuclear Medicine and Molecular Imaging.