Spatially‐localized NMR spectroscopy employing an inhomogeneous surface‐spoiling magnetic field gradient 1. Phase coherence spoiling theory and gradient coil design

Wei Chen, Joseph J.H. Ackerman

Research output: Contribution to journalReview article

9 Citations (Scopus)

Abstract

The use of a current‐generated, inhomogeneous, surface‐spoiling magnetic field gradient for enhancing magnetic resonance spatial localization, by rapidly inducing spin phase incoherence in surface lying regions of a sample is examined theoretically. A geometrically simple surface‐spoiling magnetic field gradient coil design is presented and its gradient field characterized via computer simulations. Mathematical expressions describing the time dependence of net sample spin phase coherence under influence of the spoiling gradient are developed for application with homogeneous (B1) volume coils. The dependence of spoiling efficiency on the magnetogyric ratio of the nuclide under investigation and on the current driving the gradient field is described. Spoiling periods of ca 1–2 ms with driving currents of ca 0.5–1.0 A are predicted to be adequate for surface‐spoiling experiments with rat, e.g., for noninvasive monitoring of liver. A companion article W. Chen and J. J. H. Ackerman, NMR Biomed., 3, 158–165 (1990)) describes implementation of the surface‐spoiling technique with multicompartment models (phantoms) and with rat in vivo.

Original languageEnglish (US)
Pages (from-to)147-157
Number of pages11
JournalNMR in biomedicine
Volume3
Issue number4
DOIs
StatePublished - Aug 1990

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Magnetic Fields
Nuclear magnetic resonance spectroscopy
Rats
Magnetic Resonance Spectroscopy
Magnetic fields
Magnetic resonance
Liver
Computer Simulation
Isotopes
Nuclear magnetic resonance
Monitoring
Computer simulation
Experiments

Cite this

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title = "Spatially‐localized NMR spectroscopy employing an inhomogeneous surface‐spoiling magnetic field gradient 1. Phase coherence spoiling theory and gradient coil design",
abstract = "The use of a current‐generated, inhomogeneous, surface‐spoiling magnetic field gradient for enhancing magnetic resonance spatial localization, by rapidly inducing spin phase incoherence in surface lying regions of a sample is examined theoretically. A geometrically simple surface‐spoiling magnetic field gradient coil design is presented and its gradient field characterized via computer simulations. Mathematical expressions describing the time dependence of net sample spin phase coherence under influence of the spoiling gradient are developed for application with homogeneous (B1) volume coils. The dependence of spoiling efficiency on the magnetogyric ratio of the nuclide under investigation and on the current driving the gradient field is described. Spoiling periods of ca 1–2 ms with driving currents of ca 0.5–1.0 A are predicted to be adequate for surface‐spoiling experiments with rat, e.g., for noninvasive monitoring of liver. A companion article W. Chen and J. J. H. Ackerman, NMR Biomed., 3, 158–165 (1990)) describes implementation of the surface‐spoiling technique with multicompartment models (phantoms) and with rat in vivo.",
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TY - JOUR

T1 - Spatially‐localized NMR spectroscopy employing an inhomogeneous surface‐spoiling magnetic field gradient 1. Phase coherence spoiling theory and gradient coil design

AU - Chen, Wei

AU - Ackerman, Joseph J.H.

PY - 1990/8

Y1 - 1990/8

N2 - The use of a current‐generated, inhomogeneous, surface‐spoiling magnetic field gradient for enhancing magnetic resonance spatial localization, by rapidly inducing spin phase incoherence in surface lying regions of a sample is examined theoretically. A geometrically simple surface‐spoiling magnetic field gradient coil design is presented and its gradient field characterized via computer simulations. Mathematical expressions describing the time dependence of net sample spin phase coherence under influence of the spoiling gradient are developed for application with homogeneous (B1) volume coils. The dependence of spoiling efficiency on the magnetogyric ratio of the nuclide under investigation and on the current driving the gradient field is described. Spoiling periods of ca 1–2 ms with driving currents of ca 0.5–1.0 A are predicted to be adequate for surface‐spoiling experiments with rat, e.g., for noninvasive monitoring of liver. A companion article W. Chen and J. J. H. Ackerman, NMR Biomed., 3, 158–165 (1990)) describes implementation of the surface‐spoiling technique with multicompartment models (phantoms) and with rat in vivo.

AB - The use of a current‐generated, inhomogeneous, surface‐spoiling magnetic field gradient for enhancing magnetic resonance spatial localization, by rapidly inducing spin phase incoherence in surface lying regions of a sample is examined theoretically. A geometrically simple surface‐spoiling magnetic field gradient coil design is presented and its gradient field characterized via computer simulations. Mathematical expressions describing the time dependence of net sample spin phase coherence under influence of the spoiling gradient are developed for application with homogeneous (B1) volume coils. The dependence of spoiling efficiency on the magnetogyric ratio of the nuclide under investigation and on the current driving the gradient field is described. Spoiling periods of ca 1–2 ms with driving currents of ca 0.5–1.0 A are predicted to be adequate for surface‐spoiling experiments with rat, e.g., for noninvasive monitoring of liver. A companion article W. Chen and J. J. H. Ackerman, NMR Biomed., 3, 158–165 (1990)) describes implementation of the surface‐spoiling technique with multicompartment models (phantoms) and with rat in vivo.

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