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Reduction of signal fluctuation in functional MRI using navigator echoes
Author(s) -
Hu Xiaoping,
Kim SeongGi
Publication year - 1994
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.1910310505
Subject(s) - signal (programming language) , reduction (mathematics) , nuclear magnetic resonance , computer science , physics , mathematics , geometry , programming language
Functional magnetic resonance imaging is sensitive to signal fluctuations due to physiological motion and system instability. In this paper, motion‐related signal fluctuations are studied, and a method that uses navigator echoes to monitor and compensate for signal fluctuations in a gradient‐echo sequence is described. The technique acquires a “navigator” signal before the application of the phase‐encoding and readout gradients and corrects the phase of the subsequently acquired imaging data. This technique was implemented on a 4 Tesla whole body system and validated on normal volunteers. With this technique, temporal fluctuations in image intensity were substantially reduced and improved functional activation maps were obtained.