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Highly efficient square wave distant dipolar field and its application for in vivo MRI
Author(s) -
Cai Congbo,
Gao Fenglian,
Cai Shuhui,
Zhong Jianhui,
Chen Zhong
Publication year - 2010
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.22486
Subject(s) - adiabatic process , square wave , dipole , physics , nuclear magnetic resonance , quantum , square (algebra) , computational physics , optics , atomic physics , molecular physics , quantum mechanics , mathematics , voltage , geometry
Intermolecular multiple quantum coherences generated by distant dipolar field (DDF) have some attractive properties, but the intrinsic weak signal intensity prevents their widespread applications. Recently, Branca et al. (J Chem Phys 2008;129:054502) suggested that square wave DDF was more efficient than conventional sinusoidal DDF because it could simultaneously produce intermolecular multiple quantum coherences signal with various major orders. In this article, instead of a series of adiabatic inversion pulses proposed previously, a more efficient composite adiabatic inversion pulse was applied to create square wave DDF. The square wave DDF was applied to in vivo MRI for the first time, and the corresponding simulations were performed. Both experimental and simulated results show that square wave DDF with composite adiabatic inversion pulse improves over the original Z‐modulation enhanced to binary for self‐refocused acquisition implementation and can enhance the signal intensity to about 2‐fold of that from conventional correlation spectroscopy (COSY) revamped with asymmetric Z‐gradient echo detection sequence for in vivo MRI, close to the theoretical prediction. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.