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. 2001 Jul;46(1):198-201.
doi: 10.1002/mrm.1177.

Artifact due to B(0) fluctuations in fMRI: correction using the k-space central line

E Durand  1 , P F van de Moortele, M Pachot-Clouard, D Le Bihan
Affiliations

Artifact due to B(0) fluctuations in fMRI: correction using the k-space central line

E Durand et al. Magn Reson Med. 2001 Jul.

Abstract

Magnetic resonance experiments require the main magnetic field, B(0), to remain very stable. Several external sources, such as moving ferromagnetic objects and/or changing electromagnetic fields, can significantly change the value of B(0) over time. This work describes an apparent displacement along the phase-encoding axis caused by a variation in B(0). This artifact was observed in fMRI images acquired with EPI. The effect was characterized and tested using an immobile phantom. The image displacement motion along the phase-encoding axis closely followed the changes in B(0). The phase of the central line in the Fourier space was successfully used to correct this artifact. Fluctuations in B(0) may result in artifacts that mimic subject head motion, and must be appropriately corrected. Magn Reson Med 46:198-201, 2001.

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