Evaluation of superagers functional parameters from pet studies using partial volume correction

• Ano de defesa: 2021
• Autor(a) principal: Andrade, Michele Alberton
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Pontifícia Universidade Católica do Rio Grande do Sul; Escola de Medicina; Brasil; PUCRS; Programa de Pós-Graduação em Gerontologia Biomédica
• Palavras-chave em Português: Superaging; Partial Volume Correction; Positron Emission Tomography; CIENCIAS DA SAUDE::MEDICINA
• Link de acesso: http://tede2.pucrs.br/tede2/handle/tede/9943

The growth of the elderly population has led to further observation and analysis of old age individuals' lives and the variables that affect successfully aging. Normal aging is associated with cognitive decline and gradual brain volume loss, although these changes do not occur to the same extent in all regions. However, some older adults maintain their cognitive ability similar to adults 20 to 30 years younger, named superagers. As many aspects of pathology can be studied in vivo due to the development of biomarkers, quantification of PET images became a topic of interest because it could detect asymptomatic stages of brain diseases. In this sense, the correction of partial volume effects (PVEs) is a processing step that reduces bias in quantification. In aging studies, this topic is critical due to the brain atrophy related to aging and neurodegenerative diseases, leading to an incorrect estimation of the biomarkers. There is a growing interest in the successful cognitive aging trajectory; we hypothesized that PVE bias might influence PET neuro findings on the superagers. Therefore, in this study, we aimed to examine PVE correction's effect on 18F-FDG and 11C-PIB PET studies of superagers and its influence on group discrimination. Our sample consisted of community-dwelling individuals at or above 80 years of age and individuals between 50 to 65 years that underwent neurological examination, neuropsychological screening, MRI, and PET imaging. PET data were corrected for PVEs using two methods (GTM and RBV). Global and regional analyses were performed. Our results partially confirm previous neuroimaging findings on the superagers, demonstrating that, if not corrected, PVE can bias results. After partial volume correction, superagers presented some regional differences in glucose metabolism compared to their peers in frontal, temporal, and parietal regions but no differences in amyloid deposition. In conclusion, the degree of change between corrected and uncorrected data is highly regional and dependent on the subject condition. The PVC methods used in this work demonstrated to decrease PVE bias, and these findings motivate additional research on PVC strategies regarding brain aging studies and superaging.