Events Calendar

MRI of Bound and Pore Water Concentration in Cortical Bone

Speaker: Mary Katherine Mansard, Ph.D., Vanderbilt University

Talk Title: MRI of Bound and Pore Water Concentration in Cortical Bone

Series: Medical Imaging Seminar Series

Abstract: The current standard for diagnosing fracture risk comprises measurements of bone mineral density (BMD), primarily by dual-energy X-ray absorptiometry (DXA). However, bone strength is affected by many factors other than BMD, such as architecture, collagen content, and porosity. Nuclear magnetic resonance (NMR) measures of the water bound to the collagen matrix (bound water) and free water occupying pore space (pore water) have shown promise in further assessing fracture risk. The work presented here translates NMR based techniques into Magnetic Resonance Imaging (MRI) methods using an ultra-short echo time (UTE) acquisition; the Double Adiabatic Full Passage (DAFP) sequence for measuring pore water concentration and the Adiabatic Inversion Recovery (AIR) sequence to measure bound water concentration. These imaging methods can be used to obtain maps of bound and pore water content throughout the cortical bone volume. MRI methods were first validated against NMR methods and shown to have good repeatability in vivo, and then were compared to whole bone material properties and found to show significant correlations with strength and toughness. The AIR and DAFP methods, initially carried out with 3D data acquisition, were further improved by implementing half-pulse 2D UTE sequences which significantly reduced scan times to under a minute. The sequences are now being applied in populations of healthy and osteoporotic patients for longitudinal evaluation. In short, measures of bound and pore water concentration have the potential to give a new and more thorough evaluation of bone characteristics and health that is not obtainable with currently used methods.



Biography: Mary Kate Manhard received her B.S. degree in Electrical Engineering from Clemson University in 2010 and completed her Ph.D. at Vanderbilt in Biomedical Engineering under the direction of Dr. Mark Does in 2016. She is a member of the Vanderbilt University Institute of Imaging Science, and her research focuses on using Magnetic Resonance Imaging (MRI) to probe cortical bone characteristics as a potential predictor of fracture risk. She has implemented bone imaging protocols for a 3T Philips clinical scanner, and has verified that MRI bone measurements report on ex vivo material properties of bone. Recently, she has been applying her work to osteoporotic patients to assess response to treatment using bone MRI measurements.

Host: Professor Krishna Nayak

Location: Hughes Aircraft Electrical Engineering Center (EEB) - 132

Audiences: Everyone Is Invited

Contact: Talyia White