Frayne, RichardWang, Xing2021-01-222021-01-222021-01-11Wang, X. (2021). Assessment of T2 Magnetic Resonance Relaxation as an Imaging Biomarker of Normal Brain Aging over the Adult Lifespan (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.http://hdl.handle.net/1880/112992Quantitative T2 relaxation time (qT2) was proposed for assessing brain tissue changes. In this study, qT2 was evaluated to examine normal brain aging across the adult lifespan. I explored the specific hypotheses that 1) short- (weeks) and long-term (years) qT2 repeatability were equivalent, and 2) qT2 increased with age-related increases in tissue water content and demyelination but decreased with increased iron accumulation. The repeatability assessment found qT2 estimation robust over >4 years. Long-term was similar to, but worse than short-term repeatability. A quadratic regression model was determined to be the best fitting analytical model. Linear mixed effects models were used to evaluate qT2 changes with age in twelve regions and qT2 change rates from six regions compared against a reference region. The results supported the hypothesis that qT2 increases with age; however, could not demonstrate that these T2 changes result from changes in tissue water content, demyelination or iron accumulation.engUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.brainagingMRIT2 relaxation timeage-related tissue property changesrepeatabilityregressionlinear mixed effects (LME) modelEngineering--Biomedicalmaster thesis10.11575/PRISM/38565