Magnetic resonance elastography (MRE) is a technique capable of creating sensitive maps of brain viscoelastic mechanical properties, which can be used as markers of brain microstructural health and have been extensively studied in neurodegeneration. However, brain mechanical changes during maturation have yet to be comprehensively explored. Here we present preliminary brain mechanical property findings from sixty-four healthy subjects from three age groups: 5-7 years, (N =17), 12-14 years (N=24), and 19-21 years (N=22). We use fast-acquisition OSCILLATE MRE at 1.5 mm resolution to capture displacement data, which is converted to whole-brain maps of viscoelastic shear stiffness (μ) through the non-linear inversion equation.
We found that whole-brain stiffness was significantly different in the 18-21 group compared to the two younger groups. Average stiffness decreased 7.54% between the 5-7 and 18-21 groups (3.05 vs. 2.82 kPa; p<0.001), with no difference found between the 5-7 and 12-14 age groups (3.05 vs. 3.08 kPa). Notably, we find that mechanical properties do change regionally during maturation. Of the subcortical gray matter structures (SGMs), the thalamus, caudate, pallidum and putamen becoming stiffer with maturation, while the amygdala and hippocampus show no decrease or potentially even an increase in stiffness with age. Interestingly, the four SGMs that decrease in stiffness with age, all are components of brain networks important for procedural learning and locomotion regulation, while the hippocampus and amygdala of the medial temporal lobe and are critical in emotional regulation, decision making, and memory formation. The differential change in mechanical properties may reflect how these functions mature.
Here we present measures of maturational brain mechanical properties that will allow for the compilation of a comprehensive set of standardized, high resolution, brain mechanical property maps for prominent time points during development. These measures are pressingly important to inform future studies investigating the neural basis of neurodevelopmental disorders.
…Read more
Less…