A portable scanner for brain MRI

• Published in: Nature biomedical engineering Vol. 5; no. 3; pp. 229 - 239
• Main Authors: Cooley, Clarissa Z., McDaniel, Patrick C., Stockmann, Jason P., Srinivas, Sai Abitha, Cauley, Stephen F., Śliwiak, Monika, Sappo, Charlotte R., Vaughn, Christopher F., Guerin, Bastien, Rosen, Matthew S., Lev, Michael H., Wald, Lawrence L.
• Format: Journal Article
• Language: English
• Published: 23-11-2020
• ISSN: 2157-846X
• DOI: 10.1038/s41551-020-00641-5

Access to scanners for magnetic resonance imaging (MRI) is typically
limited by cost and by infrastructure requirements. Here, we report the design
and testing of a portable prototype scanner for brain MRI that uses a compact
and lightweight permanent rare-earth magnet with a built-in readout field
gradient. The 122-kg low-field (80 mT) magnet uses has a Halbach-cylinder design
that results in minimal stray field and requires neither cryogenics nor external
power. The built-in magnetic-field gradient reduces the reliance on high-power
gradient drivers, lowering the overall requirements for power and cooling, and
reducing acoustic noise. Imperfections in the encoding fields are mitigated with
a generalized iterative image-reconstruction technique that leverages prior
characterization of the field patterns. In healthy adult volunteers, the scanner
can generate T
1
-weighted, T
2
-weighted and
proton-density-weighted brain images with a spatial resolution of 2.2 ×
1.3 × 6.8 mm
3
. Future versions of the scanner could improve
the accessibility of brain MRI at the point of care, particularly for critically
ill patients.