Premium
Effects of inductive coupling on parallel MR image reconstructions
Author(s) -
Ohliger Michael A.,
Ledden Patrick,
McKenzie Charles A.,
Sodickson Daniel K.
Publication year - 2004
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.20195
Subject(s) - nuclear magnetic resonance , coupling (piping) , image (mathematics) , computer science , physics , artificial intelligence , materials science , metallurgy
Theoretical arguments and experimental results are presented that characterize the impact of inductive coupling on the performance of parallel MRI reconstructions. A simple model of MR signal and noise reception suggests that the intrinsic amount of spatial information available from a given coil array is unchanged in the presence of inductive coupling, as long as the sample remains the dominant source of noise for the coupled array. Any loss of distinctness in the measured coil sensitivities is compensated by information stored in the measured noise correlations. Adjustments to the theory are described to account for preamplifier noise contributions. Results are presented from an experimental system in which preamplifier input impedances are systematically adjusted in order to vary the level of coupling between array elements. Parallel image reconstructions using an array with four different levels of coupling and an acceleration factor up to six show average SNR changes of −7.6% to +7.5%. The modest changes in overall SNR are accompanied by similarly small changes in g‐factor. These initial results suggest that moderate amounts of inductive coupling should not have a prohibitive effect on the use of a given coil array for parallel MRI. Magn Reson Med 52:628–639, 2004. © 2004 Wiley‐Liss, Inc.