Harnessing brain waves: a review of brain magnetic resonance elastography for clinicians and scientists entering the field

Abstract

Brain magnetic resonance elastography (MRE) is an imaging technique capable of accurately and non-invasively measuring the mechanical properties of the living human brain. Recent studies have shown that MRE has potential to provide clinically useful information in patients with intracranial tumors, demyelinating disease, neurodegenerative disease, elevated intracranial pressure, and altered functional states. The objectives of this review are: (1) to give a general overview of the types of measurements that have been obtained with brain MRE in patient populations, (2) to survey the tools currently being used to make these measurements possible, and (3) to highlight brain MRE-based quantitative biomarkers that have the highest potential of being adopted into clinical use within the next 5 to 10 years. The specifics of MRE methodology strategies are described, from wave generation to material parameter estimations. The potential clinical role of MRE for characterizing and planning surgical resection of intracranial tumors and assessing diffuse changes in brain stiffness resulting from diffuse neurological diseases and altered intracranial pressure are described. In addition, the emerging technique of functional MRE, the role of artificial intelligence in MRE, and promising applications of MRE in general neuroscience research are presented.

Fluid compartments influence elastography of the aging mouse brain

“…There are a number of questions from MRE of the human brain that require clarification. In a recent review article (Arani et al 2021 ), the authors point out that a general consensus regarding the effects of aging on the brain of adult humans is that the brain will soften over time, however not all studies agree on the magnitude of this effect (Hiscox et al 2021 , Coelho and Sousa 2022 ). Furthermore, some significant baseline parameters such as the relative stiffness of cortical grey matter versus cerebral white matter do not have a strong consensus across reports.…”

“…Elastography applied to the brain is a relatively recent and promising avenue of research using magnetic resonance imaging, ultrasound, and optical coherence tomography (OCT) imaging systems in clinical and pre-clinical settings. An overarching goal is to discover sensitive biomarkers related to the viscoelastic properties of the brain (Hiscox et al 2016 , 2018 , 2021 , Bigot et al 2018 , Gerischer et al 2018 , Munder et al 2018 , Guo et al 2019 , Murphy et al 2019 , Arani et al 2021 ) that can be targeted for diagnosis. These previous studies demonstrate that there are changes in brain viscoelastic properties with age, injury, and disease.…”

Integrating material properties from magnetic resonance elastography into subject-specific computational models for the human brain

“…Material properties of the brain have also been measured in vivo in human volunteers using magnetic resonance elastography (MRE), which involves the calculation of local and subject-specific brain mechanics under low, harmonically-induced strain [ 41 , 42 ]. While the properties are derived from brain displacements in the magnitude of microns, MRE allows for the calculation of material properties for individual voxels without altering the natural environment of the brain [ 43 , 44 ].…”

Magnetic resonance elastography of the ageing brain in normal and demented populations: A systematic review

“…The studies encompassed in their work were also part of the present review, but we additionally included recent studies, some with high resolution MRE, that reinforced previous results. Furthermore, we also investigated the available evidence regarding alterations in brain stiffness during normal aging, which despite having already been addressed in other reviews (Arani et al, 2021 ; Hiscox et al, 2021 ; Yin et al, 2018 ), it was not the subject of any previous systematic review.…”