Lightweight, compact, and high-performance 3T MR system for imaging the brain and extremities

Thomas K.F. Foo, Evangelos Laskaris, Mark Vermilyea, Minfeng Xu, Paul Thompson, Gene Conte, Christopher Van Epps, Christopher Immer, Seung Kyun Lee, Ek T. Tan, Dominic Graziani, Jean Baptise Mathieu, Christopher J. Hardy, John F. Schenck, Eric Fiveland, Wolfgang Stautner, Justin Ricci, Joseph Piel, Keith Park, Yihe HuaYe Bai, Alex Kagan, David Stanley, Paul T. Weavers, Erin Gray, Yunhong Shu, Matthew A. Frick, Norbert G. Campeau, Joshua Trzasko, John Huston, Matt A. Bernstein

Research output: Contribution to journalArticlepeer-review

33 Scopus citations


Purpose: To build and evaluate a small-footprint, lightweight, high-performance 3T MRI scanner for advanced brain imaging with image quality that is equal to or better than conventional whole-body clinical 3T MRI scanners, while achieving substantial reductions in installation costs. Methods: A conduction-cooled magnet was developed that uses less than 12 liters of liquid helium in a gas-charged sealed system, and standard NbTi wire, and weighs approximately 2000 kg. A 42-cm inner-diameter gradient coil with asymmetric transverse axes was developed to provide patient access for head and extremity exams, while minimizing magnet-gradient interactions that adversely affect image quality. The gradient coil was designed to achieve simultaneous operation of 80-mT/m peak gradient amplitude at a slew rate of 700 T/m/s on each gradient axis using readily available 1-MVA gradient drivers. Results: In a comparison of anatomical imaging in 16 patients using T2-weighted 3D fluid-attenuated inversion recovery (FLAIR) between the compact 3T and whole-body 3T, image quality was assessed as equivalent to or better across several metrics. The ability to fully use a high slew rate of 700 T/m/s simultaneously with 80-mT/m maximum gradient amplitude resulted in improvements in image quality across EPI, DWI, and anatomical imaging of the brain. Conclusions: The compact 3T MRI system has been in continuous operation at the Mayo Clinic since March 2016. To date, over 200 patient studies have been completed, including 96 comparison studies with a clinical 3T whole-body MRI. The increased gradient performance has reliably resulted in consistently improved image quality.

Original languageEnglish (US)
Pages (from-to)2232-2245
Number of pages14
JournalMagnetic Resonance in Medicine
Issue number5
StatePublished - Nov 2018

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging


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