Brain Magnetic Resonance Elastography Experiments With an Electromagnetic Actuator

Magnetic resonance elastography (MRE) enables non-invasive assessment of the mechanical properties of brain tissue, which is crucial for diagnosing neurodegenerative diseases and understanding brain development. This technique relies on inducing controlled harmonic deformation in brain tissue and detecting the resulting motion via motion-sensitive magnetic resonance imaging (MRI) sequences. Electromagnetic actuators, which leverage the static magnetic field of MRI scanners and Lorentz law to generate rotary vibration, offer a cost-effective solution for brain MRE. However, their application in brain MRE requires addressing MRI safety challenges from metallic components and coil positioning inflexibility. Here, we present a comprehensive protocol for designing, constructing, and implementing an electromagnetic actuator tailored for brain MRE experiments. We detail key considerations including design of an actuator capable of reducing electromagnetic interference and vibration stimulation, construction of a controller for the actuator, design schematic of an MRE sequence, and methods for obtaining final mechanical results of MRE. This protocol aims to provide a practical guide for research laboratories seeking to develop MRE systems, facilitating accurate and reproducible assessment of brain mechanical properties for both basic research and clinical translation.