Neuroimaging in Alzheimer's disease: current role in clinical practice and potential future applications

Abstract

Alzheimer's disease is the most common cause of dementia and its prevalence is expected to increase in the coming years. Therefore, accurate diagnosis is crucial for patients, clinicians and researchers. Neuroimaging techniques have provided invaluable information about Alzheimer's disease and, owing to recent advances, these methods will have an increasingly important role in research and clinical practice. The purpose of this article is to review recent neuroimaging studies of Alzheimer's disease that provide relevant information to clinical practice, including a new modality: in vivo amyloid imaging. Magnetic resonance imaging, single photon emission computed tomography and 18F-fluorodeoxyglucose-positron emission tomography are currently available for clinical use. Patients with suspected Alzheimer's disease are commonly investigated with magnetic resonance imaging because it provides detailed images of brain structure and allows the identification of supportive features for the diagnosis. Neurofunctional techniques such as single photon emission computed tomography and 18F-fluorodeoxyglucose-positron emission tomography can also be used to complement the diagnostic investigation in cases of uncertainty. Amyloid imaging is a non-invasive technique that uses positron emission tomography technology to investigate the accumulation of the β-amyloid peptide in the brain, which is a hallmark of Alzheimer's disease. This is a promising test but currently its use is restricted to very few specialized research centers in the world. Technological innovations will probably increase its availability and reliability, which are the necessary steps to achieve robust clinical applicability. Thus, in the future it is likely that amyloid imaging techniques will be used in the clinical evaluation of patients with Alzheimer's disease.

Precision Medicine - The Golden Gate for Detection, Treatment and Prevention of Alzheimer’s Disease

“…These plaques are predominantly found in the precuneus, anterior and posterior cingulate, parietal, frontal and lateral temporal cortices, a characteristic distribution which can be used for visual reading of PET scans. The visual cortex and the primary sensorimotor cortex are spared of Aβ deposits until very late in the course of the AD, consistent with the sequence of subsequent clinical symptomatology (121). The utility of pattern-based analyses of presence and progression of cognitive loss and potential for precision medicine approaches remains unknown.…”

Younger Onset Dementia

“…19 Awareness of YOD may have changed in recent years, with improvements in neuroimaging technology and diagnostic procedures that may influence the identification of cases with dementia. [27][28][29] The Australian Institute of Health and Welfare (AIHW) report 7 used United Kingdom estimates 17,18 for the under-60 age-group but data from a more recent meta-analysis 25 for the other age-groups. The AIHW 7 estimated that there were 23 900 Australians, younger than 65 years, with YOD in 2011.…”

The role of optical coherence tomography in Alzheimer’s disease

“…Neuroimaging techniques are essential in the diagnosis of AD and magnetic resonance imaging (MRI) has become the most used tool for cerebral imaging in AD patients, providing detailed information about brain structure. The most common findings in MRI of patients with AD are atrophy in the medial temporal lobe, including hippocampus, amygdala, entorhinal cortex and parahippocampal gyrus, ventricular enlargement and reduction of total brain volume [7]. Although studies have not yet completely elucidated the structural and functional changes that occur in brains of AD patients, some clinical and histologic studies suggest that the same neurodegenerative process that occurs in the brain, may also affect the retina, since the latter represents a peripheral part of central nervous system.…”