Biomedical subjects

D N Guilfoyle

Publications and source records attributed to D N Guilfoyle.

6 recordsLinked to original sources

PubMed1992

Magnetic resonance imaging: applications of novel methods in studies of porous media.

NMR imaging is finding broad applications in nonbiological areas including the study of fluid flow and fluid ingress in porous media. The porous media include at the one end mineral rocks and various building materials through various solid plastic materials to foodstuffs at the other end of the spectrum. The fluids within these various media range from crude oil and water mixtures, and water itself, to a range of organic solvents in plastic materials. This paper is concerned with the flow and ingress of water through Bentheimer sandstone and Ninian reservoir specimens, and also in solid nylon blocks.

Echo-Planar Imaging↗

PubMed1991

Real-time flow measurements using echo-planar imaging.

The ultra-high-speed echo-planar imaging (EPI) method is combined with velocity encoding prior to EPI read-out, thereby allowing real-time measurement of flow. Results of EPI flow measurement experiments are presented on phantoms and human volunteers.

Blood Flow Velocity↗

PubMed1991

Observation of cerebrospinal fluid flow with echo-planar magnetic resonance imaging.

Using echo-planar (EP) magnetic resonance imaging (MRI), cerebrospinal fluid (CSF) flow patterns have been demonstrated in the normal subject and patients with pathological conditions including communicating hydrocephalus, aqueduct stenosis and syringohydromyelia. Snap-shot imaging times of 128 ms allow detailed demonstration of transient intraventricular CSF flow patterns, which is not possible with conventional MRI. The potential of EPI as a method for qualitative and quantitative assessment of CSF dynamics is illustrated.

Cerebral Aqueduct↗

PubMed1989

PEEP--a rapid chemical-shift imaging method.

The phase-encoded echo-planar (PEEP) technique, a variant of echo-planar imaging, is used to achieve simultaneous high-speed spatial and chemical-shift data acquisition. This technique is the 2DFT equivalent of the projection reconstruction echo-planar method for chemical-shift imaging. Examples of images and spectra obtained using the PEEP method are presented.

Magnetic Resonance Imaging↗

PubMed1986

Measurement of T1 by echo-planar imaging and the construction of computer-generated images.

The high-speed echo-planar imaging (EPI) technique is used to obtain rapid T1 and spin density measurements by a two-point method. It is shown that neglect of edge effects in the slice selection procedure leads to significant systematic errors in T1. T1 maps for two young patients, obtained at 4.0 MHz, are presented. The T1 and spin density values obtained are used to produce computer-generated images in inversion recovery simulations. These results demonstrate marked improvement in image contrast without paying the time penalty incurred in real experiments, thereby greatly increasing patient throughput potential.

Abdomen↗

PubMed1985

Chemical-shift imaging.

The echo-planar shift mapping (EPSM) technique, a variant of echo-planar imaging (EPI), is evaluated with theoretical studies using computer simulations and with experimental studies using fluorine resonances in phantoms. In situations where the signal-to-noise ratio permits, it is shown that EPSM can produce in a few seconds chemical-shift spectra at all points in a specified spin-density image corresponding to a selected slice. Applications of this technique are likely to be for proton and fluorine chemical-shift measurements and rapid studies of magnetic field inhomogeneities produced by magnet non-alignment and field shifts around magnetic materials.

Computers↗