Abstract:
:Due to the presence of gross magnetic susceptibility artifacts, functional MRI (fMRI) has proved problematic in studies of the human inferior frontal cortex (IFC). There is a strong desire, therefore, to employ techniques that mitigate susceptibility artifacts in the IFC while preserving the imaging parameters of an fMRI study. It has been shown that the use of a single, strongly diamagnetic, intra-oral passive shim significantly improves the homogeneity of the static magnetic field (B(0)) and, as a result, alleviates the susceptibility artifacts within the IFC. In this study, practical issues regarding the use of an intra-oral passive shim are examined. We investigated B(0) instabilities within the IFC resulting from subject head motion in order to calculate the effects of an intra-oral passive shim on the temporal variance of an EPI time series. These studies show that the addition of an intra-oral passive shim improves both B(0) homogeneity and signal stability, and increases sensitivity to functional activation.
journal_name
Magn Reson Medjournal_title
Magnetic resonance in medicineauthors
Wilson JL,Jezzard Pdoi
10.1002/mrm.10626subject
Has Abstractpub_date
2003-11-01 00:00:00pages
1089-94issue
5eissn
0740-3194issn
1522-2594journal_volume
50pub_type
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