Portable, High Resolution NMR/MRI in Inhomogeneous Fields

APPLICATIONS OF TECHNOLOGY:

Multidimensional imaging for medical diagnosis, especially when rapid diagnosis is critical
Ex situ nondestructive evaluation of suspicious substances for homeland security
Nondestructive evaluation for quality control at production sites
Inexpensive NMR for benchtop chemical analysis

ADVANTAGES:

Enables high-resolution NMR and MRI outside of the laboratory and in highly non-uniform magnetic fields
Samples can be outside of the magnet and thus of any size
Portable and significantly less expensive than large, stationary magnet systems
Reveals chemical shifts of eight parts per million within three minutes

ABSTRACT:

A tube of oil and and a tube of water were imaged together using the Berkeley Lab ex situ NMR/MRI method. The direct and two-phase encoding dimensions yielded the 3D images.

Alexander Pines and colleagues at Berkeley Lab have developed a method to improve NMR/MRI resolution either inside of poorly shimmed magnets or outside of portable one-sided magnet systems, which accommodate arbitrarily sized samples. This technique will enable for the first time the collection of multidimensional NMR/ MRI information in cases where on-the-spot medical diagnosis is critical, where samples cannot be moved to or placed inside of a superconducting magnet, or where inexpensive, highly inhomogeneous magnets are being used. Other ex situ systems give relaxation data and sometimes slice-selective images, but not spectra and true 3D images.

The Berkeley Lab method combines elements of two previous inventions by the Pines research group, RF field matching (IB-1717) and shim pulse refocusing (IB-2026), to alleviate the exacting hardware requirements of the RF field matching method and reduce the power and other technical requirements of shim pulse refocusing.

The original RF field matching technique corrects static magnetic field variations with correlative radio frequency field inhomogeneity created by a series of RF pulses precisely varied in energy, duration, and timing. This method requires a well-defined RF field produced by a coil specifically designed to reproduce the spatial static field dependence or just a monotonic behavior. The original shim pulse method depends on modulation of the RF and gradient pulses to create an effectively “shimmed” field. By combining the two techniques, the Berkeley Lab researchers have developed a less demanding and therefore less expensive ex situ methodology.

STATUS: Issued US Patent 8614575 available at www.uspto.gov . Available for licensing or collaborative research.

FOR MORE INFORMATION:

Demas, V., Sakellariou, D., Meriles, C. A., Han, S., Reimer, J., Pines, A., “Three-dimensional Phase-encoded Chemical Shift MRI in the Presence of Inhomogeneous Fields,” PNAS 2004, 101, 8845-8847.

Topgaard,D., Martin, R.W., Sakellariou, D., Meriles, C.A., Pines, A., ” ‘Shim Pulses’ for NMR Spectroscopy anmd Imaging,” PNAS 2004, 101, 17576-17581.

Perlo, J., Demas, V., Casanova, F., Meriles, C., Reimer, J., Pines, A., Blumich, B., “High-Resolution NMR Spectroscopy with a Portable Single-Sided Sensor,” Science 2005, 308, 1279.

REFERENCE NUMBER: IB-2185

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