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Advanced three‐dimensional tailored RF pulse for signal recovery in T 2 *‐weighted functional magnetic resonance imaging
Author(s) -
Yip Chunyu,
Fessler Jeffrey A.,
Noll Douglas C.
Publication year - 2006
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.21048
Subject(s) - dephasing , pulse (music) , imaging phantom , signal (programming language) , magnetic resonance imaging , nuclear magnetic resonance , phase (matter) , physics , pulse sequence , computer science , materials science , optics , detector , medicine , quantum mechanics , radiology , programming language
T 2 * ‐weighted functional MR images are plagued by signal loss artifacts caused by susceptibility‐induced through‐plane dephasing. We present major advances to the original three‐dimensional tailored RF (3DTRF) pulse method that pre‐compensates the dephasing using three‐dimensional selective excitation. The proposed 3DTRF pulses are designed iteratively with off‐resonance incorporation and with a novel echo‐volumar trajectory that frequency‐encodes in z and phase‐encodes in x,y . We also propose a computational scheme to accelerate the pulse design process. We demonstrate effective signal recovery in a 5‐mm slice in both phantom and inferior brain, using 3DTRF pulses that are only 15.4 ms long. Compared to the original method, the new approach leads to significantly reduced pulse length and enhancement in slice selectivity. 3D images of the slice volume confirm fidelity of the excited phase pattern and slice profile. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.