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Functional quantitative susceptibility mapping (fQSM)




Samuel J. Wharton

Gisela E. Hagberg

Klaus Scheffler


Blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) is a powerful technique, typically based on the statistical analysis of the magnitude component of the complex time-series. Here, we additionally interrogated the phase data of the fMRI time-series and used quantitative susceptibility mapping (QSM) in order to investigate the potential of functional QSM (fQSM) relative to standard magnitude BOLD fMRI. High spatial resolution data (1 mm isotropic) were acquired every 3 seconds using zoomed multi-slice gradient-echo EPI collected at 7 T in single orientation (SO) and multiple orientation (MO) experiments, the latter involving 4 repetitions with the subject's head rotated relative to B0. Statistical parametric maps (SPM) were reconstructed for magnitude, phase and QSM time-series and each was subjected to detailed analysis. Several fQSM pipelines were evaluated and compared based on the relative number of voxels that were coincidentally found to be significant in QSM and magnitude SPMs (common voxels). We found that sensitivity and spatial reliability of fQSM relative to the magnitude data depended strongly on the arbitrary significance threshold defining “activated” voxels in SPMs, and on the efficiency of spatio-temporal filtering of the phase time-series. Sensitivity and spatial reliability depended slightly on whether MO or SO fQSM was performed and on the QSM calculation approach used for SO data. Our results present the potential of fQSM as a quantitative method of mapping BOLD changes. We also critically discuss the technical challenges and issues linked to this intriguing new technique.


Balla, D. Z., Sánchez-Panchuelo, R., Wharton, S. J., Hagberg, G. E., Scheffler, K., Francis, S. T., & Bowtell, R. (2014). Functional quantitative susceptibility mapping (fQSM). NeuroImage, 100, 112-124.

Journal Article Type Article
Acceptance Date Jun 2, 2014
Online Publication Date Jun 16, 2014
Publication Date Oct 15, 2014
Deposit Date Sep 22, 2016
Publicly Available Date Sep 22, 2016
Journal NeuroImage
Print ISSN 1053-8119
Electronic ISSN 1095-9572
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 100
Pages 112-124
Keywords fMRI; Functional QSM; MR phase imaging; Susceptibility mapping; Quantitative BOLD; Specific brain activation
Public URL
Publisher URL
Additional Information This article is maintained by: Elsevier; Article Title: Functional quantitative susceptibility mapping (fQSM); Journal Title: NeuroImage; CrossRef DOI link to publisher maintained version:; Content Type: article; Copyright: Copyright © 2014 Elsevier Inc. All rights reserved.


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