Events Calendar

Far out Experiments in MRI using FM Pulses

Speaker: Michael Garwood, University of Minnesota

Talk Title: Far out Experiments in MRI using FM Pulses

Series: Medical Imaging Seminar Series

Abstract: Magnetic resonance imaging (MRI) uses radiofrequency (RF) irradiation to excite and manipulate nuclear spins. In multiple disciplines of MRI, significant gains in experimental precision and new experimental capabilities are made possible by RF pulses that are frequency modulated (FM). This presentation will show clinically relevant examples of how FM pulses can be exploited for MRI.

FM pulses can be used not only to improve data quality, but also to reveal spin dynamics, such as dipole-dipole interactions and exchange between spins on different molecules. The ability to modulate the pulse frequency, as well as the pulse amplitude, creates almost limitless possibilities to sensitize the MRI signal to molecular motions happening on slow time scales. This presentation will show how this novel approach can create contrast for better delineating normal anatomy and disease states.

By exploiting unique features of FM pulses, we have also developed a radically different approach to produce MR images. The technique is called SWIFT (sweep imaging with Fourier transformation). The FM pulse used in SWIFT makes possible simultaneous or time-shared excitation and acquisition. The smooth change of gradient orientation used in SWIFT produces negligible acoustic noise, making image acquisition close to silent.

Finally, spatiotemporal-encoding methods using FM pulses have been attracting much interest recently. In particular, the spatiotemporal domain allows direct treatment of spatial problems like B0 and B1 inhomogeneity. I will describe a new spatiotemporal MRI technique called STEREO (steering resonance over the object). This unique technique excites MR signals locally and steers the localized region over the object in a spatiotemporal manner. STEREO provides a means to accomplish multi-dimensional spatiotemporal-encoded MRI in a manner that permits compensation for extreme magnetic field inhomogeneity. With STEREO, MR images are reconstructed using exclusively an inverse problem solution (i.e., no Fourier transformation).

ACKNOWLEDGEMENT: this research is funded by NIH grant P41 EB15894


Biography: Michael Garwood, Ph.D. is a Professor in the Department of Radiology and Associate Director of the Center for Magnetic Resonance Research, at the University of Minnesota, where he has been for the past 27 years. He holds the Lillian Quist – Joyce Henline Chair in Biomedical Research. Dr. Garwood was educated at the University of California, Santa Cruz, where he received bachelors degrees in biology and chemistry in 1981, and a Ph.D. in chemistry in 1985. In his time at the University of Minnesota, he has made many significant contributions to the field of biomedical NMR, mostly involving MRI technology development for better detection and assessment of therapies for cancer, Alzheimer’s disease, and other disorders. He has many awards and honors, including the Gold Medal from the International Society of Magnetic Resonance in Medicine. Dr. Garwood has published more than 170 scientific papers and is an inventor on 15 patents.

Host: Professor Krishna Nayak

More Info: http://mhi.usc.edu/medical-imaging-seminar-series/

Location: Hughes Aircraft Electrical Engineering Center (EEB) - 248

Audiences: Everyone Is Invited

Contact: Talyia Veal

Event Link: http://mhi.usc.edu/medical-imaging-seminar-series/