Local mechanical properties of white matter structures in the human brain

Abstract

The noninvasive measurement of the mechanical properties of brain tissue using magnetic resonance elastography (MRE) has emerged as a promising method for investigating neurological disorders. To date, brain MRE investigations have been limited to reporting global mechanical properties, though quantification of the stiffness of specific structures in the white matter architecture may be valuable in assessing the localized effects of disease. This paper reports the mechanical properties of the corpus callosum and corona radiata measured in healthy volunteers using MRE and atlas-based segmentation. Both structures were found to be significantly stiffer than overall white matter, with the corpus callosum exhibiting greater stiffness and less viscous damping than the corona radiata. Reliability of both local and global measures was assessed through repeated experiments, and the coefficient of variation for each measure was less than 10%. Mechanical properties within the corpus callosum and corona radiata demonstrated correlations with measures from diffusion tensor imaging pertaining to axonal microstructure.

Suitability of poroelastic and viscoelastic mechanical models for high and low frequency MR elastography

“…Data from five repeated examinations of a healthy volunteer are available for both 50 Hz external actuation 40,43 and 1 Hz intrinsic actuation. 11 The IA subject was a 51 yr old male and the five MRE datasets were acquired over a 22 month period, whereas the EA subject was a 24 yr old male and the MRE data were acquired over a two month period.…”

Magnetic Resonance Elastography Demonstrating Low Brain Stiffness in a Patient with Low-Pressure Hydrocephalus: Case Report

“…MRE is also being increasingly used for presurgical evaluation of meningioma consistency [26,27]. Our group has significant experience in the design and application of MRE methodology for studying the human brain in vivo [6,9,10,28,29]. Previously, we demonstrated that viscoelastic property measures derived from brain MRE are very reliable with coefficients of variation from repeated measurements in the order of 5% [6].…”

“…Our group has significant experience in the design and application of MRE methodology for studying the human brain in vivo [6,9,10,28,29]. Previously, we demonstrated that viscoelastic property measures derived from brain MRE are very reliable with coefficients of variation from repeated measurements in the order of 5% [6]. A recent repeatability study using the same methodology as in this work found the coefficient of variation for cerebral stiffness to be less than 2% [30].…”

“…It has been hypothesized that LPH is caused by a brain that has a higher-than-normal compliance [1]; however, until recently, there has been no reliable method to measure brain tissue compliance noninvasively. Here we present the case of a 19-year-old female who presented with LPH where we performed a magnetic resonance elastography (MRE) [5,6] scan to measure her brain stiffness following treatment.…”

“…Across the cerebrum, including all white and gray matter but excluding regions of CSF [6,8], her average stiffness was 1.62 kPa. This is approximately 46% softer than the normal brain that generally exhibits a stiffness of approximately 3.0 kPa in healthy populations at 50 Hz [6,9]. This patient had very low tissue stiffness, and thus very high tissue compliance, consistent with previous hypotheses of the causation and etiology of LPH.…”