Magnetic Susceptibility in ex-vivo Human Brain Tissue and Electron Paramagnetic Ressonance: Correlation with Experimental Conditions

• Grant number: 23/04823-3
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: July 01, 2023
• End date: June 30, 2024
• Field of knowledge: Physical Sciences and Mathematics - Physics
• Principal Investigator: Carlos Ernesto Garrido Salmon
• Grantee: André Avanzine
• Host Institution: Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (FFCLRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

The aging process and progression of certain neurodegenerative diseases, such as Parkinson's and Alzheimer's, have been linked to increased accumulation of metals in the brain, such as iron and copper. While these metals play important metabolic roles, an imbalance in their concentrations can lead to cell death. Quantitative Susceptibility Mapping (QSM) is useful in characterizing the metal content of different regions of the human brain by mapping the magnetic susceptibility Ç from phase images obtained by magnetic resonance imaging. Recently, new mapping methods (DECOMPOSE and Ç-separation) have allowed for the separation of paramagnetic and diamagnetic components of susceptibility. Electron Paramagnetic Resonance (EPR) is a technique that characterizes electronic media, indicating the types of compounds, or more precisely, paramagnetic ions present in a given sample through their spectra. In conjunction with this analysis, mass spectrometry (ICP-MS) can be performed to reveal the absolute concentration of some metals. However, it is not known exactly how external factors such as temperature, age, and post-mortem interval (PMI) affect the measurement of Ç and the estimation of metal content. Therefore, this project proposes to use QSM, EPR, and ICP-MS techniques together to evaluate the relationship between the components of Ç and metal concentrations in order to compare the results obtained with previous correlations made in previous studies. Additionally, it is intended to describe the paramagnetic state of the species detected by EPR in different regions of the brain based on measurements with varying temperatures.