Jones Seminar: Imaging the Mechanics of the Brain Using MRI

Optional ZOOM LINK
Meeting ID: 961 8109 4666
Passcode: 005351

Brain mechanical behavior can be strongly affected by disease processes. For example, microstructural alterations manifest as changes in macroscale mechanical properties, and changes to the mechanical environment disturb the mechanisms of waste clearance which is a major contributor to the development of dementia. In vivo imaging of brain mechanics provides an important opportunity for diagnosis and monitoring.

Most imaging approaches use waves to probe some physical property in the world. For example, photography uses visible light to image the scattering and reflection of object surfaces, x-ray and CT imaging use higher energy electromagnetic radiation to image the attenuation coefficient of bones and tissues, and ultrasound uses sound waves to image reflection and attenuation properties of soft tissues. Similarly, imaging of the mechanical properties of brain can be achieved using mechanical waves as a probe.

We have developed "magnetic resonance elastography" which uses various types of mechanical waves to form images. The shear modulus of isotropic brain tissues such as gray matter can be estimated from the shear wave velocity. Fiber-reinforced anisotropic tissues such as white matter have both a fast and slow shear wave which allows anisotropic properties to be imaged. Low frequency motion from cardiac pulsation has an additional poroelastic slow wave produced by fluid redistribution which allows us to compute the hydraulic conductivity, as well as image the stresses and pressure gradients which drive the glymphatic flows that clear waste products from the brain.

About the Speaker(s)

Matthew McGarry
Assistant Professor of Engineering, Dartmouth

Originally from Nelson, New Zealand, Matt McGarry began working on brain mechanics during his master's research at the University of Canterbury, continued for a PhD at Dartmouth, postdoctoral work in ultrasound imaging at Columbia, and finally returned to Dartmouth as an assistant professor. His lab focuses on developing new methods for in vivo mechanical imaging and finding clinical applications through a network of collaborators at DHMC and around the world.

Contact

For more information, contact Ashley Parker at ashley.l.parker@dartmouth.edu.