It is the dream of researcher's and clinician's to have available a low cost, portable MRI scanner for brain neuroimaging. However, such a low cost MRI system requires a small bore MRI magnet. Unfortunately, in the case of conventional MRI systems, small bore magnets have a usable homogeneous magnetic field Diameter Spherical Volume (DSV) that is much smaller than the size of the human brain. A new MRI approach is required to achieve the dream of a low cost portable MRI brain scanner. The general methodology used to obtain MR images today is essentially the same as that used approximately 40 years ago. In the NIH Brain Initiative funded project NIH R24 MH105998-01 - in which University of Minnesota (CMMR) is the PI, and Wang NMR, Yale University and Harvard University are key participants. - we have successfully demonstrated the feasibility of a revolutionary new MRI imaging method called STEREO which stands for STEering REsonance over the Object. By generating MRI imaging with spatiotemporal encoding, STEREO allows the Bo field to vary by amounts as large as 200 kHz or +/- 1500 ppm Bpk-pk. Therefore, STEREO for the first time, makes it possible for a much smaller bore MRI magnet, with an inherently less homogeneous magnet field, to permit good MRI imaging. In addition, it is possible to observe brain activity with zero echo time by using the SWIFT imaging technique. Using SWIFT, it is possible to transmit FM pulses and simultaneous receive signals making MRI neuroimaging an extremely inhomogeneous magnet possible. This SBIR proposal intends to exploit the unique imaging technologies demonstrated in our previous NIH funded project and to build a low cost, commercially viable MRI system with a small, light weight (250 lb.) magnet with a small bore as small as 34 cm in diameter X 34 cm long (dimensions that are 3 times smaller than traditional neuroimaging MRI magnets). The magnet will employ the lowest cost superconductor NbTi, and will be conduction cooled be a small cryo-cooler. There will be no nitrogen and helium required at all. Therefore it can be operated in any country so long as there is electricity. The magnet will be combined with a new, low cost, dynamic multi-coil gradient shimming system for Bo field modulation and with a low cost, low power (50 W) compact simultaneous transmit and receive RF spectrometer system. Successful completion of this SBIR project will demonstrate a revolutionary, portable, low cost, commercially viable MRI system for brain neuroimaging. We expect to see in the near future such brain imaging systems available for use everywhere, and to permit the imaging of brain function in all populations and environments worldwide.
In this project, a revolutionary 1.5 T magnetic resonance imaging (MRI) system to image human brain activity is designed, built, and fully tested. The imaging technology is a new type of MRI that works with a small, lightweight (250 lb.), portable and low cost head-only magnet. The compactness and efficiency of this imaging system makes the study of human brain possible outside the unnatural laboratory environment and in subjects who previously were excluded from getting an MRI scan.
