Parallel magnetic resonance (MR) imaging may be used to increase either the
throughput or the speed of the MR imaging experiment. As such, parallel imaging may
be accomplished either through a "parallelization" of the MR experiment, or by the use
of arrays of sensors. In parallelization, multiple MR scanners (or multiple sensors) are
used to collect images from different samples simultaneously. This allows for an
increase in the throughput, not the inherent speed, of the MR experiment. Parallel
imaging with arrays of sensor coils, on the other hand, makes use of the spatial
localization properties of the sensors in an imaging array to allow a reduction in the
number of phase encodes required in acquiring an image. This reduced phase-encoding
requirement permits an increase in the overall imaging speed by a factor up to the
number of sensors in the imaging array. The focus of this dissertation has been the
development of cost-effective instrumentation that would enable advances in the state of
the art of parallel MR imaging.
First, a low-cost desktop MR scanner was developed (< $13,000) for imaging small
samples (2.54 cm fields-of view) at low magnetic field strengths (< 0.25 T). The
performance of the prototype was verified through bench-top measurements and
phantom imaging. The prototype transceiver has demonstrated an SNR (signal-to-noise ratio) comparable to that of a commercial MR system. This scanner could make
parallelization of the MR experiment a practical reality, at least in the areas of small
animal research and education.
A 64-channel receiver for parallel MR imaging with arrays of sensors was also
developed. The receiver prototype was characterized through both bench-top tests and
phantom imaging. The parallel receiver is capable of simultaneous reception of up to
sixty-four, 1 MHz bandwidth MR signals, at imaging frequencies from 63 to 200 MHz,
with an SNR performance (on each channel) comparable to that of a single-channel
commercial MR receiver. The prototype should enable investigation into the speed
increases obtainable from imaging with large arrays of sensors and has already been
used to develop a new parallel imaging technique known as single echo acquisition
(SEA) imaging.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/4784 |
| Date | 25 April 2007 |
| Creators | Brown, David Gerald |
| Contributors | Wright, Steven M. |
| Publisher | Texas A&M University |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Dissertation, text |
| Format | 3663304 bytes, electronic, application/pdf, born digital |
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