Spread spectrum MRI
US5999838A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 24, 1997 |
| Grant date | Dec 7, 1999 |
| Priority date | — |
| Expiry date | Jul 24, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R33/4625
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method for acquiring data from voxels in a contour of tissue includes positioning the tissue in a magnetic field. For the present method, a z-gradient is imposed on the contour tissue to spread the spectrum of all of the voxels over a same range of Larmor frequencies. Additionally, voxels in the contour tissue are selectively encoded with different x-gradients and y-gradients to distinguish the various voxels from each other. In the presence of the z-gradient, nuclei of the encoded voxel are tilted and then refocused at a rate proportional to the z-gradient. Due to this refocusing, spin echo signals are generated which are useful for acquiring data from the tissue. The intravoxel z-gradient used for the present invention is the same for all voxels and is greater than either the x-gradient or the y-gradient which are used for encoding. The z-gradient may be substantially constant. Importantly, the z-gradient is sufficiently extensive to spread the spectrum of the spin echo signals for suppression of exogenous noise and make the signals immune to static field perturbations.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.