Meeting Banner
Abstract #0300

Experimental Investigation of the Relation Between Gradient Echo BOLD fMRI Contrast and Underlying Susceptibility Changes at 7T

Dvid Z. Balla1, Rosa M. Sanchez Panchuelo2, Samuel J. Wharton2, Gisela E. Hagberg1, 3, Klaus Scheffler1, 3, Susan T. Francis2, Richard W. Bowtell2

1High-field MR Centre, Max Planck Institute for Biological Cybernetics, Tbingen, Germany; 2Sir Peter Mansfield Magnetic Resonance Centre, University of Nottingham, Nottingham, United Kingdom; 3Department for Biomedical Magnetic Resonance Imaging, University of Tbingen, Tbingen, Germany

Gradient echo BOLD fMRI contrast was compared to the underlying local susceptibility changes, calculated from the same time-series using functional quantitative susceptibility mapping (fQSM). Comparing voxels coincidentally activated in both fQSM and GE-fMRI, differences were found between motor, visual and somatosensory paradigms in the respective brain areas. In most of these common voxels the signs of susceptibility and magnitude change were opposite confirming expectations. Yet, in a significant number of voxels the signs matched, suggesting strong non-local contributions. Experiments with the motor paradigm showed positive susceptibility shifts and magnitude signal changes in deep cortical layers.

Abstract PDF Presentation Video

Keywords

acquisition activated activation active analyses appear applied around axes bias bingen biological biomedical biophysical block blood bold brain calls capillaries channel coarse coefficients coil coincident common component contrast contrasts correlation corroborating cortex cortical covariance cross datasets deeper density dependence dependent depending diagram diamagnetic differently distribution dork dynamics efficient even expected experienced experimentally explicit field filtering flash focusing function functional generally gradient head highest highlights increasing induced intensity intra investigated investigation involving layers linear linearly local magnitude mapping maps materials motor negative noise numerical observation onto opposite optimal optimized orientation oriented outcome outcomes overlaid oxygenation paradigms peter phys physiological pipeline plot positions positive power proportional proposed quantitative receive related relation repetitions reserve resolution resolutions robust rotated scatter select series several sharp sign simulations since slice specificity spectral stimulation strengths strong studied subject substantial suggesting suggests surface surrounding susceptibility system task temporal threshold tissue transverse uncorrected underlying unexpected veins visual volunteers ways yields