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Computer simulation of MRS localization techniques: An analysis of ISIS
Author(s) -
Lawry T. J.,
Karczmar G. S.,
Weiner M. W.,
Matson G. B.
Publication year - 1989
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.1910090302
Subject(s) - signal (programming language) , saturation (graph theory) , pulse (music) , nuclear magnetic resonance , optics , computer science , signal processing , materials science , acoustics , physics , telecommunications , mathematics , combinatorics , detector , programming language , radar
Computer simulations were used to evaluate the ISIS localization technique as implemented with both head and surface coils. The effects ofchemical shift, B 1 inhomogeneity, repetition time, T 2 relaxation, a postacquisition saturation pulse, and a B 1 insensitive observation pulse were examined. Integrals of ISIS signals over the sample volume showed that significant signal loss from the volume of interest (VOI) and contamination from outside the VOI can occur for both head and surface coil ISIS experiments. The results showed that the saturation pulse, order of the various ISIS acquisitions, and repetition time affect contamination but not signal loss. In addition, short T 2 and high RF power can combine synergistically to degrade the selective inversion pulses, causing further contamination and signal loss. © 1989 Academic Press, Inc.