Longitudinal MR Elastography of Brain Mechanical Property Maturation During Adolescence

Motivation: Magnetic resonance elastography (MRE) sensitively captures structural changes in the brain. However, application of this technique has been limited to cross-sectional studies in adolescents. Goal(s): Our aim was to examine, for the first time, longitudinal changes in MRE-derived brain tissue mechanical properties during adolescence. Approach: Shear stiffness and damping ratio were calculated for 14 adolescents during two study visits separated by a year. Results: Stiffness significantly decreased over one year. The largest stiffness declines were in subcortical gray matter, in agreement with cross-sectional studies. Changes in both shear stiffness and damping ratio were correlated with progression of puberty. Impact: This longitudinal study found wide-spread softening of brain tissue during adolescence, supporting cross-sectional findings. These changes were also correlated with the progression of puberty. This confirms the sensitivity of mechanical properties to capture structural changes of brain maturation.