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Sources of distortion in functional MRI data.
1FMRIB Centre, Department of Clinical Neurology, University of Oxford, UK. peterj@fmrib.ox.ac.uk
Human Brain Mapping
|October 19, 1999
Summary
This study reviews common artifacts in functional magnetic resonance imaging (fMRI) data. Understanding these magnetic resonance signal changes is crucial for accurate neurological interpretation.
Area of Science:
- Neuroimaging
- Biophysics
- Medical Physics
Background:
- Functional magnetic resonance imaging (fMRI) is essential for detecting subtle signal changes in brain activity.
- Accurate interpretation of fMRI data relies on high-quality magnetic resonance imaging time series.
- Numerous artifacts can degrade fMRI data quality, impacting the reliability of findings.
Purpose of the Study:
- To review common artifacts encountered in fMRI data.
- To describe the impact of magnetic field inhomogeneities on echo planar imaging (EPI) and spiral imaging.
- To discuss motion-related distortions and gradient coil nonlinearities in fMRI.
Main Methods:
- Review of existing literature on fMRI artifacts.
- Analysis of the effects of magnetic field inhomogeneities on EPI and spiral data.
- Discussion of subject motion effects and gradient coil nonlinearities.
Main Results:
- Magnetic field inhomogeneities significantly distort EPI and spiral imaging data.
- Subject motion exacerbates these distortions, further compromising data quality.
- Gradient coil nonlinearities and EPI ghosting are additional sources of artifact.
Conclusions:
- Artifacts in fMRI data can severely degrade image quality and complicate interpretation.
- Understanding and mitigating these artifacts, particularly those from magnetic field inhomogeneities and motion, is critical for reliable fMRI studies.
- Addressing gradient nonlinearities and ghosting is also important for robust fMRI analysis.