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Low-Field MRI with Improved Resolution and Portability Using Gradient Fields of Arbitrary Size



  • Ex situ (single-sided) MRI
    • Borehole MRI
    • Materials testing (e.g., food, historical buildings and structures, tires)
  • Portable low-field MRI for:
    • Oil fields at any depth, using MRI devices that can be lowered into the borehole
    • Joints, brain, prostate, heart, lungs (may be used with hyperpolarized noble gas)
  • Mobile MRI scanners
    • Large objects (e.g., racing horses or other animals)
  • Online MRI (reaction and process monitoring)
  • Combining MRI and magnetoencepholography (MEG) to study brain activity
  • Magnetic force microscopy


  • Enhances the portability of low-field MRI
  • Increases maximum achievable resolution of low-field MRI
  • Can work without a homogeneous background field
  • Works with gradient fields of arbitrary size
  • Compatible with:
    • SQUID and other atomic magnetometers
    • Inductive detectors (e.g., Faraday detectors)
  • No need for post-corrections


Alexander Pines of Berkeley Lab and fellow researchers have invented a new MRI system that significantly increases the maximum achievable resolution of low-field MRI, without the need for a strong uniform background field. Whereas most conventional MRI methods rely on constant background magnetic fields (B0) 5–10 times larger than the maximum gradient field in order to compensate for image distortions from nonuniform gradients, Pines and his colleagues have found a way of substituting a strong homogeneous background field with a train of strong field pulses that are typically five times larger than the maximum gradient field.

By removing the requirement for a constant background field, the Berkeley Lab invention can enhance the portability of low-field MRI for materials testing, oil fields, and the human body (including the brain, prostate, heart, joints, limbs with metal implants, or lungs that may be filled with a hyperpolarized noble gas such as xenon). The invention may also be used to improve mobile MRI scanners for imaging large objects or animals, monitoring chemical and biological reactions and processes, and magnetic force microscopy.

Without the need for a strong homogeneous background field, the Berkeley Lab invention also removes limitations on the maximum size of a field gradient. The new Berkeley Lab pulsed low-field MRI makes it possible to achieve a higher degree of image resolution without gradient size restrictions.


  • Issued Patent #7,750,633 available at Available for licensing or collaborative research.

To learn more about licensing a technology from LBNL see


Meriles, C.A., Sakellariou, D., Trabesinger, A.H., Demas, V., and Pines, A., "Zero- to Low-field MRI with Averaging of Concomitant Gradient Fields," Proc. Natl. Acad. Sci. USA, 2005, 102; 1840–1842.




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