NMR imaging of blood flow by moment variation of magnetic gradients
US4718424A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 7, 1986 |
| Grant date | Jan 12, 1988 |
| Priority date | — |
| Expiry date | Aug 7, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R33/56316
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Selective material projection imaging in which static and flowing material are distinguishable utilizes magnetic gradients whose waveforms have selective moments. The effects of the magnetic field gradients are utilized in obtaining data for a plurality of images whereby the subtraction of image data will result in selected material imaging. The zero moment of a magnetic gradient waveform affects the phase of static material and the phase of moving material, while the first moment of a magnetic gradient waveform affects the phase of constant velocity moving material but not the phase of static material. The second moment of a magnetic gradient waveform affects the phase of varying velocity moving material but not the phase of static material or constant velocity material. The nuclear spins of a region of a body can be excited under different conditions of an applied magnetic field gradient so that data under the different conditions can be subtracted to eliminate selected material. Alternatively, the two magnetic field gradient can be applied during the preparatory periods or the read-out periods in obtaining the data for the two images.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.