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GESCHEIDTOVÁ, E. KUBÁSEK, R. SMÉKAL, Z. BARTUŠEK, K.
Original Title
Digital Filter Banks in MR Measurement of Gradient Magnetic Fields
Type
journal article in Web of Science
Language
English
Original Abstract
The sensitivity of spectroscopic methods based on nuclear magnetic resonance is limited, in particular by the magnitude of noise in the signal being measured. In MR tomography and, above all, in localized spectroscopy and spectroscopic MR imaging, this problem becomes even more pronounced. When gradient magnetic fields are used, it cannot be fully ruled out that there will be a change in the basic magnetic field due to the eddy currents in conducting materials in the neighbourhood of the sample being measured. This results in a local change in instantaneous frequency of the resonance of nuclei and in a distortion of spectral lines or MR image. For methods that eliminate this distortion and for an accurate calculation of the constants of (in particular long) pre-emphasis filters, techniques have been developed and experimentally tested that are based on measuring the instantaneous frequency of the signal detected with a very low signal-to-noise ratio. Adaptive filtering methods and filtering based on filter banks have been developed to reduce efficiently the level of noise. Results of the two types of filtering are described in the paper. The filtering techniques developed can be used also in other applications and thus contribute to increasing the quality of methods for examining the properties of biological and chemical substances.
Keywords
Digital filter, bank of filters, NMR, instantenous frequency
Authors
GESCHEIDTOVÁ, E.; KUBÁSEK, R.; SMÉKAL, Z.; BARTUŠEK, K.
RIV year
2008
Released
1. 5. 2008
Publisher
Springer
Location
Wien
ISBN
0937-9347
Periodical
Applied Magnetic Resonance (IF 0,665)
Year of study
33
Number
4
State
Republic of Austria
Pages from
399
Pages to
417
Pages count
19
BibTex
@article{BUT47447, author="Eva {Gescheidtová} and Radek {Kubásek} and Zdeněk {Smékal} and Karel {Bartušek}", title="Digital Filter Banks in MR Measurement of Gradient Magnetic Fields", journal="Applied Magnetic Resonance (IF 0,665)", year="2008", volume="33", number="4", pages="399--417", issn="0937-9347" }