Original title: Some comments on frequency selective excitation in newly proposed MRSI sequences
Authors: Starčuk jr., Zenon ; Horký, Jaroslav ; Starčuk, Zenon ; Mlynárik, V. ; Gruber, S. ; Moser, E.
Document type: Papers
Conference/Event: NMR Valtice, Valtice (CZ), 2002-04-28 / 2002-04-30
Year: 2003
Language: eng
Abstract: In many pathologies it is desirable to compare the metabolism inside a lesion, near the lesion, and in healthy tissue. The diagnostic value of MRS is enhanced by spectroscopic imaging (MRSI), permitting the simultaneous acquisition of spatially resolved spectra. In this way, assessing metabolic information about different brain regions within a single examination is possible. As with all in vivo spectroscopy, low signal-to-noise ratio (SNR) is the fundamental limiting factor in MRSI due to very low concentrations of metabolites of interest. Proton spectroscopic imaging, however, offers additional technical challenges as compared to single-voxel techniques, especially if acquisition of short echo time (TE<30 ms) is required. Critical to the success of proton MRSI studies of the human brain is the elimination of the very intense water and lipid signals arising from outside the volume of interest (VOI). Water suppression in MRSI can be very problematic in MRSI, in which the achievable degree of water suppression is limited by B.sub.0./sub. and B.sub.1./sub. inhomogeneities and water T.sub.1./sub. variations, invariably present throughout the larger VOIs. Suppression of liquid signals (from bone marrow and subcutaneous fat) is often severely complicated due to the fact that their relaxation behavior differs substantially from that of water. One of the basic approaches used to reduce the undesired contamination if the MRSI signals of interest consists in the use of the STEAM or PRESS selective excitation of the VOI. Both STEAM and PRESS techniques suffer from some drawbacks. STEAM reduces the sensitivity of measurement, PRESS has higher RF power requirements.
Keywords: human brain; metabolic information; MR spectroscopy imaging
Project no.: GA202/02/1493 (CEP), CEZ:AV0Z2065902 (CEP)
Host item entry: Proceedings of 18.sup.th./sup. conference on NMR in Valtice, ISBN 80-210-3092-5

Institution: Institute of Scientific Instruments AS ČR (web)
Document availability information: Fulltext is available at the institute of the Academy of Sciences.
Original record: http://hdl.handle.net/11104/0101313

Permalink: http://www.nusl.cz/ntk/nusl-29613


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Research > Institutes ASCR > Institute of Scientific Instruments
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 Record created 2011-07-01, last modified 2017-01-18


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