Article 2020

Dynamic B0 shimming of the motor cortex and cerebellum with a multicoil shim setup for BOLD fMRI at 9.4T

{PURPOSE: We assessed how improved static magnetic field (B0 ) homogeneity with a dynamic multicoil shimming can influence the blood oxygen level dependent (BOLD) contrast to noise when echo planar imaging (EPI) sequence is used for a motor task functional MRI study. We showed that a multicoil shim setup can be a proper choice for dynamic shimming of 2 spatially distant areas with different inhomogeneity distributions. METHODS: A 16-channel multicoil shim setup is used to provide improved B0 homogeneity by dynamic slice-wise shimming. The performance of dynamic B0 shimming was investigated in 2 distinct brain regions, the motor cortex and the cerebellum, in the same experiment during a finger-tapping task. Temporal SNR (tSNR), geometric distortion of the EPIs, and results of an analysis with a general linear model before and after shimming with the multicoil were compared. RESULTS: Reduced B0 deviation by 30\textpercent and 52\textpercent in the cerebellum and motor cortex, respectively, resulted in higher tSNR and a reduction of distortions in the EPI. Statistical analysis applied to the EPIs showed higher t values and increased number of voxels above significance threshold when shimming with the multicoil setup. CONCLUSIONS: Improved B0 homogeneity leads to higher tSNR and enhances the detection of BOLD signal.}

Author(s): Aghaeifar, A and Bause, J and Leks, E and Grodd, W and Scheffler, K
Journal: {Magnetic Resonance in Medicine}
Volume: 83
Number (issue): 5
Pages: 1730--1740
Year: 2020
Publisher: Wiley-Liss
Project(s):
Bibtex Type: Article (article)
DOI: 10.1002/mrm.28044
Address: New York
Electronic Archiving: grant_archive

BibTex

@article{item_3176086,
  title = {{Dynamic B0 shimming of the motor cortex and cerebellum with a multicoil shim setup for BOLD fMRI at 9.4T}},
  journal = {{Magnetic Resonance in Medicine}},
  abstract = {{PURPOSE: We assessed how improved static magnetic field (B0 ) homogeneity with a dynamic multicoil shimming can influence the blood oxygen level dependent (BOLD) contrast to noise when echo planar imaging (EPI) sequence is used for a motor task functional MRI study. We showed that a multicoil shim setup can be a proper choice for dynamic shimming of 2 spatially distant areas with different inhomogeneity distributions. METHODS: A 16-channel multicoil shim setup is used to provide improved B0 homogeneity by dynamic slice-wise shimming. The performance of dynamic B0 shimming was investigated in 2 distinct brain regions, the motor cortex and the cerebellum, in the same experiment during a finger-tapping task. Temporal SNR (tSNR), geometric distortion of the EPIs, and results of an analysis with a general linear model before and after shimming with the multicoil were compared. RESULTS: Reduced B0 deviation by 30\textpercent and 52\textpercent in the cerebellum and motor cortex, respectively, resulted in higher tSNR and a reduction of distortions in the EPI. Statistical analysis applied to the EPIs showed higher t values and increased number of voxels above significance threshold when shimming with the multicoil setup. CONCLUSIONS: Improved B0 homogeneity leads to higher tSNR and enhances the detection of BOLD signal.}},
  volume = {83},
  number = {5},
  pages = {1730--1740},
  publisher = {Wiley-Liss},
  address = {New York},
  year = {2020},
  slug = {item_3176086},
  author = {Aghaeifar, A and Bause, J and Leks, E and Grodd, W and Scheffler, K}
}