Development of Advanced MR Elastography Techniques for Biomechanical Assessment of Neurodegeneration

Abstract

Alzheimer’s disease (AD) is the leading cause of dementia in the aging population worldwide, and a progressive neurodegenerative condition of enormous socio-economic impact. Identification of non-invasive correlates of these pathologies to aid diagnosis in the earliest stages of disease will help to afford improved disease management and prevention. One such non-invasive correlate that has received growing attention involves the study of the mechanical properties of the brain via MR Elastography (MRE) , as it is becoming increasingly clear that tissue mechanics are related to the underlying cellular microstructure and overall health state of an organ. Pivotal studies applying MRE at 3T have shown a progressive softening of white and gray matter tissue in AD patients compared to healthy controls (especially in the frontal, parietal and temporal lobes) in line with the known topography of AD pathology. One of the limitations of this approach, however, is that the underlying microstructural causes of tissue viscoelasticity variations cannot be directly determined, hence there is a lack of physical understanding regarding the meaning of these parameters in the context of dementia and neurodegeneration. This difficulty limits the current predictive value of MRE for early diagnosis and for the assessment of individual risk of developing cognitive decline. This work seeks to investigate noise reduction and applications of ultra-high field (7T) magnetic resonance elastography (MRE) in determining the mechanical properties of brain tissue, with applications in early detection of dementias.