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

Abstract

The aim of this systematic review was to evaluate the ability of magnetic resonance elastography (MRE) to identify significant changes in brain mechanical properties during normal and pathological aging. PubMed, Web of Science and Scopus were searched for human studies using MRE to assess brain mechanical properties in cognitively healthy individuals, individuals at risk of dementia or patients diagnosed with dementia. Study characteristics, sample demographics, clinical characterization and main MRE outcomes were summarized in a table. A total of 19 studies (nine aging, 10 dementia), comprising 700 participants, were included. The main findings were decreased cerebral stiffness along aging, with rates of annual change ranging from −0.008 to −0.025 kPa per year. Also, there were regional differences in the age effect on brain stiffness. Concerning demented patients, differential patterns of stiffness were found for distinct dementia subtypes. Alzheimer's disease and frontotemporal dementia exhibited decreased brain stiffness in comparison to cognitively healthy controls and significant declines were found in regions known to be affected by the disease. In normal pressure hydrocephalus, the results were not consistent across studies, and in dementia with Lewy bodies no significant differences in brain stiffness were found. In conclusion, aging is characterized by the softening of brain tissue and this event is even more pronounced in pathological aging, such as dementia. MRE technique could be applied as a sensible diagnostic tool to identify deviations from normal aging and develop new brain biomarkers of cognitive decline/dementia that would help promote healthier cognitive aging.

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.…”

Imaging Markers for Normal Pressure Hydrocephalus: An Overview

“…Magnetic resonance elastography (MRE) has been proposed as a helpful tool in differentiating dementia from normal aging. In MRE, iNPH is found to have decreased brain stiffness in the periventricular areas and increased stiffness in parietal and occipital areas; however, the results for the whole brain were inconclusive [53].…”

Substrate stiffness in nerve cells

“…Brain stiffness is related to many factors, such as sex, age, brain location, and the presence or absence of brain disease. Stiffness is increased in the developing brain [49] 29 and decreases with age [50][51][52][53]. On the other hand, the occipital and temporal lobes of females generally have a higher stiffness than those of males of the same age [50,53].…”

“…Stiffness is increased in the developing brain [49] and decreases with age [50–53]. On the other hand, the occipital and temporal lobes of females generally have a higher stiffness than those of males of the same age [50, 53].…”

“…In rats, white and grey matter have different stiffness [54]. Patients with Alzheimer’s disease (AD) and frontotemporal dementia have reduced brain stiffness and softening of the parietal and sensorimotor regions [51, 55]. Magnetic resonance elastography showed stiffness changes mainly in the frontal, parietal, and temporal lobes in AD, with decreasing stiffness correlating with increasing disease severity [56–58].…”