A/Prof Viktor Vegh - Anomalous relaxation with application in tissue microstructure imaging
Abstract: The induced magnetic field from tissue microstructure can influence the relaxation process in a nuclear magnetic resonance experiment. Fractional calculus provides an opportunity to model non-classical relaxation processes in MRI and help understand circumstances under which non-monoexponential signal decay may be present. A number of fractional calculus models for MRI relaxation have been proposed and shown to better fit the MRI signal than models based on classical calculus. Here, the behaviours of certain fractional models are explored and applied to 7T human brain gradient recalled echo MRI data. Two specific applications are considered in detail. Firstly, the extended time-fractional relaxation model is used to map frequency shifts in the brain, an effect expected to reflect iron loading. Secondly, a fractional relaxation model is applied with magnetic resonance fingerprinting for cortical parcellation. The results suggest that anomalous relaxation models can provide additional insight into tissue microstructure variations in the brain.
Bio: Viktor started off in the field of Electrical Engineering, before realising that his wholesome passion lay in mathematics. As such, he switched to a degree in Applied Mathematics at the Queensland University of Technology and completed with Honours. The experience was so positive that soon after completing this degree he enrolled in a PhD in Computational and Applied Mathematics at the same University. During this time, he equipped himself with skills such as advanced computational mathematics techniques, i.e. solution of large linear systems, electromagnetics and simulation of electromagnetic waves. These competencies allowed him to pursue a post-PhD post-doctoral fellowship at the Centre for Magnetic Resonance, the University of Queensland. His synergistic background in Electrical Engineering and Mathematics underpinned his initial contributions on instrumentation design and development in NMR/MRI.
It seems that people equipped with strong analytical skills seek out other opportunities during their career. Viktor pursued opportunities in finance and, decided to complete a Master of Commerce degree with a major in Applied Finance. Interestingly, his roots in mathematics led to the choosing of final year electives such as stochastic modelling, Brownian motion in relation to stock price movements, Monte Carlo methods, martingales and more computational mathematics with primary focus on finance models (e.g. Black-Scholes equation).
More recently, Viktor has focused on research and development of medical imaging methods for the direct in vivo mapping of biological effects, translatable to the diagnosis and monitoring of neurological diseases and disorders. As such, his research now focuses on understanding the underlying biological and physical processes influencing signal formation, specifically in MRI, via the use of mathematical models. Whilst his research focus has shifted over the years, it has always been, and continues to be, reinforced by his interests in the application of mathematics to real world problems. Applied finance remains a personal hobby for Viktor, in addition to cracking jokes with a straight face, offshore fishing and native Australian plants.