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Pyrolytic graphite foam: a passive magnetic susceptibility matching material
Gary C Lee1, Patrick W Goodwill, Kevin Phuong
1Berkeley/UCSF Bioengineering Joint Graduate Group, University of California, Berkeley, California 94720, USA. glee@berkeley.edu
Journal of Magnetic Resonance Imaging : JMRI
|September 4, 2010
Summary
A novel pyrolytic graphite (PG) foam cushion improves magnetic resonance imaging (MRI) by matching magnetic susceptibility, reducing artifacts, and enhancing B(0) field homogeneity for safer, more robust studies.
Area of Science:
- Biomedical Engineering
- Materials Science
- Medical Imaging Physics
Background:
- Magnetic susceptibility differences between air and human tissue cause B(0) field inhomogeneities.
- These inhomogeneities lead to susceptibility artifacts in magnetic resonance imaging (MRI).
- Minimizing these artifacts is crucial for accurate MRI studies.
Purpose of the Study:
- To evaluate a novel soft, lightweight cushion designed to match the magnetic susceptibility of human tissue.
- To assess the cushion's ability to reduce or eliminate field inhomogeneities at air/tissue interfaces.
- To determine the impact on MRI image quality and safety.
Main Methods:
- Pyrolytic graphite (PG) microparticles were embedded into a foam cushion.
- 3T MRI images and field maps of an air/water/PG foam phantom were acquired.
- Radiofrequency coil measurements and heating tests were performed at 3T and 4T.
Main Results:
- The PG foam demonstrated improved magnetic susceptibility matching.
- Field perturbations in phantoms were significantly reduced.
- The material was found to be non-heating and nonconductive.
Conclusions:
- The susceptibility-matched PG foam is lightweight and safe for patient use.
- It effectively reduces MRI artifacts and improves B(0) homogeneity.
- The material is compatible with radiofrequency coil arrays, enabling more robust MR studies.
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