Nutation angle measurement during MRI prescan
US5416412A · kind A · utility
9Cited by
8References
9Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Sep 30, 1993 |
| Grant date | May 16, 1995 |
| Priority date | — |
| Expiry date | Sep 30, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R33/586
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A prescan for an MRI system (FIG. 1) automatically sets the rf power level to produce an excitation field that nutates spins in the image plane the amount prescribed by the scan. Nutation angle is measured with a pulse sequence comprised of three slice selective excitation pulses that produce a set of frequency encoded NMR echo signals (E.sub.1, S.sub.1, E.sub.2, E.sub.23, E.sub.13). Nutation angle is calculated at locations in the image slice from the Fourier transformation of these signals and the maximum nutation angle is employed to calculate the final rf power level setting for the scan.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.