This item is only available for download by members of the University of Illinois community. Students, faculty, and staff at the U of I may log in with your NetID and password to view the item. If you are trying to access an Illinois-restricted dissertation or thesis, you can request a copy through your library's Inter-Library Loan office or purchase a copy directly from ProQuest.
Permalink
https://hdl.handle.net/2142/30818
Description
Title
Magnetic resonance microscopy
1. Four-dimensional spectral-spatial imaging
2. Diffusional effects in magnetic resonance microscopy
Author(s)
Hyslop, William Brian
Issue Date
1998
Director of Research (if dissertation) or Advisor (if thesis)
Lauterbur, Paul C.
Department of Study
Physics
Discipline
Physics
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Magnetic resonance imaging (MRI)
4D spectral-spatial magnetic resonance imaging
DESIRE (Diffusionally-Enhanced Signal Intensity and REsolution)
nuclear magnetic resonance (NMR) microscopy
Language
en
Abstract
An n-dimensional (nD) filtered backprojection image reconstruction algorithm has been
developed and used in the reconstruction of 4D spectral-spatial magnetic resonance imaging (MRI)
data. The algorithm uses n-1 successive stages of 2D filtered backprojection to reconstruct an nD
image. This approach results in a reduction in computational time on the order of Nn-2 relative to
the single stage technique, where Nn is the number of elements in an nD image. This work
describes implementation of the algorithm, including digital filtering and sampling requirements.
Images obtained from simulated data are presented to illustrate the accuracy and potential utility of
the technique.
The second part of this work studied the effects of restricted diffusion on the appearance of
magnetic resonance microscopy images. A scaling law was used to predict the onset of motional
narrowing effects for given values of diffusion, length, gradient strength, and gyromagnetic ratio.
Barriers to translational diffusion were found to result in significant edge effects. Such edge effects
were also predicted for semi-permeable barriers with permeability coefficients similar to those of
biological membranes.
DESIRE (Diffusionally-Enhanced Signal Intensity and REsolution) is a new method for
nuclear magnetic resonance (NMR) microscopy which couples a spatially localized region of
saturated magnetization to the surrounding medium via translational diffusion of spins, resulting in
amplification of the total saturated magnetization by several orders of magnitude over that obtained
in the absence of diffusion. Combined with signal detection at narrow bandwidths of the order of
the transverse relaxation rate, DESIRE results in greatly increased signal-to-noise relative to
traditional NMR imaging techniques and has the potential for submicron resolution. Both time dependent
and steady-state simulations and analytic expressions will be presented, as well as a
one-dimensional DESIRE experiment.
Use this login method if you
don't
have an
@illinois.edu
email address.
(Oops, I do have one)
IDEALS migrated to a new platform on June 23, 2022. If you created
your account prior to this date, you will have to reset your password
using the forgot-password link below.
