Early diagnosis of Alzheimer’s disease: potential of <sup>18</sup>F-FDG PET as a biomarker of neurodegeneration

BACKGROUND: Dementia is considered one of the most actual medical problems of our time, being one of the main causes of disability among the elderly, and its prevalence will only increase in the coming years. The first place among conditions leading to dementia is given to Alzheimer’s disease (up to 70%). The effectiveness of Alzheimer’s disease therapy largely depends on the timeliness of diagnosis, which leads to the need to search for diagnostic markers that allow to detect the disease at the earliest stages. AIM: To evaluate the possibilities of using 18F-FDG PET for the early diagnosis of Alzheimer’s disease. MATERIALS AND METHODS: Cerebral metabolism was assessed using positron emission tomography with 18F-FDG. A total of 183 patients were divided into groups depending on their diagnosis and the severity of cognitive impairment. RESULTS: A characteristic pattern of cerebral metabolic disorders has been established in patients with Alzheimer’s disease. It can be detected in the early pre-dementia stages and has developmental features as the disease progresses. The pattern was characterized by bilateral hypometabolism in the parietal and temporal cortex with a predominance in its mediobasal sections. An important marker of the development of the neurodegenerative process was a metabolic disorder of the cingulate gyrus, the posterior sections of which are affected already at the earliest stages of the disease, while the involvement of its anterior sections reflects the transition to the stage of severe dementia. Described metabolic disorders prevailed in the dominant (left) brain hemisphere at all stages of the disease. CONCLUSION: Currently 18F-FDG PET can be considered the most informative of the available methods for the early diagnosis of Alzheimer’s disease which have a fairly high degree of accuracy.