A new approach to NMR: High resolution spatial holographic encoding using traveling wave MR

This technology is for using a high field MR system to record interference patterns within biological phantoms combined with new spatial encoding methods to give contrast at resolution limits far exceeding traditional gradient-based encoding schemes. This interference-based approach can be used to initiate a new field of high field MR imaging.

The principal advantage of MR at high field is the concomitant increase in signal-to noise ratio (SNR). However, at high field strength, the excitation wavelength becomes commensurate with the field of view (FOV). For example, at 7 T, the free space wavelength corresponds to about 1 m. The dielectric constant in a biological sample can be as high as 80 due to the high water content, and at a spin precession frequency of 300 MHz, this corresponds to a wavelength inside tissue of less than 15 cm. The operating wavelength is thus comparable to the diameter of most in vivo FOVs. To this end, both temporal and spatial variations of the excitation field must be taken into account, as well as the expected increase in field conductivity. For these reasons, we find that the propagation of radiation at ultra high fields (> 4 T) generates new phenomena commonly observed in quantum optics but traditionally negligible in NMR experiments, including phase modulation of the excitation field as well as wave interference.

Advantages include:
• Large field of view (FOV) imaging
• Higher spatial and temporal resolution
• Open architecture MRI scanners with pulsed B0 field

Applications

This NMR technology is a new approach to spatial encoding methods and contrast, at resolution limits far exceeding gradient-based encoding schemes, using high field systems to record inference patterns within biological phantoms. The technology offered here expands the reach of current MR applications by increasing the speed and resolution of existing systems. The resolution of traditional high-field MRI systems is typically around 100 microns. The technology offered here provides a 10x to 100x increase in resolution over existing technology.

Additionally, the advantages of this technology lead to a range of new applications. In the medical field, this technology produces the ability to observe tiny changes, otherwise invisible, for diagnosing delicate structures things such as fine-scale brain lesions. In addition, this technology can be implemented in open MR systems which helps accommodate claustrophobic and large patients as well as diagnose orientation specific ailments. In the security field this technology allows one to scan objects from a distance much greater than traditional technologies. In all areas this technology improves scanning speed by up to 50%.

U.S. Patent(s) Issued: US9726736B2