Real-time MR elastography of the brain in search of the fast viscoelastic response to functional activity

Motivation: The need for advanced imaging techniques to precisely localize neuronal activity, overcoming the limitations of fMRI in terms of temporal resolution and direct measurement of neural activation. Goal(s): To determine how neural activity influences tissue stiffness by detecting viscoelastic changes associated with neuronal firing and hemodynamic responses. Approach: Using real-time MR elastography techniques to simultaneously measure both BOLD activation and viscoelastic changes in the brain during visual stimulation at two different time scales. Results: Distinct viscoelastic activation patterns strongly link neurovascular coupling and tissue stiffness. However, no rapid viscoelastic response related directly to the underlying neural activity was detected. Impact: Functional real-time MR elastography is sensitive to biomechanical property changes associated with the hemodynamic response to brain stimulation providing a valuable tool to study possible effects that occur on a subsecond timescale.