Magnetic resonance elastography of the brain: Recent advances

Abstract

Magnetic resonance elastography (MRE) is an imaging technique for generating maps of quantitative tissue mechanical properties. Mechanical properties of the brain offer sensitive new biomarkers for diagnosing neurological conditions and individual differences in brain health that support cognitive functioning. However, the mechanical complexity of the brain—e.g., heterogeneity in space and scale, frequency- and direction-dependent behavior, skull encasement—require advanced MRE techniques to reliably and accurately map brain tissue properties. We will discuss recent developments in MRE imaging and inversion methods and experiments aimed at more completely estimating brain properties. This includes approaches for determining mechanical anisotropy in white matter tracts comprising aligned axonal fiber bundles from rich acoustic wavefields. And new experiments capturing time-dependent variation in properties and the relationships to cerebral blood flow. Such advances increase the capabilities of MRE as an imaging tool and concomitantly enrich our understanding of the physiological bases of in vivo brain mechanical properties.