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Updated: Jun 9, 2026
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Quantitative Magnetic Resonance Imaging of Skeletal Muscle Disease
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Real-time Motion Compensated ΔB0 Shimming with an AC/DC Shim Coil and Dual-Echo vNavs
Nicolas Arango1, Robert Frost2,3, Paul Wighton2
1Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, United States.
Summary
Real-time shimming corrects brain magnetic field changes caused by head motion. This technique reduces image distortion in echo-planar imaging (EPI), improving MRI quality for various head positions.
Area of Science:
- Neuroimaging
- Magnetic Resonance Imaging (MRI)
Background:
- Subject head motion alters magnetic susceptibility interfaces within the brain.
- These changes induce dynamic ΔB0 field variations, leading to significant geometric distortion in echo-planar imaging (EPI).
Purpose of the Study:
- To implement and evaluate a prospective, real-time (TR-to-TR) shimming strategy.
- To correct motion-induced ΔB0 field fluctuations and minimize EPI distortion.
Main Methods:
- Utilized a 32-channel AC/DC head shim array for rapid shim field adjustments.
- Employed dual-echo EPI with volume navigators for prospective, TR-to-TR shim updating.
- Tested the method in vivo across various head positions.
Main Results:
- The TR-to-TR shimming scheme successfully corrected motion-induced ΔB0 field changes.
- Significant reduction in EPI geometric distortion was observed in all tested head positions.
- Improved image quality and spatial accuracy in dynamic neuroimaging scenarios.
Conclusions:
- Prospective, real-time shimming is an effective method for mitigating motion artifacts in EPI.
- This approach enhances the reliability and accuracy of MRI brain imaging, particularly in studies involving subject movement.
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