Sliding frequency steady-state precession imaging
US6624630B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Nov 20, 2001 |
| Grant date | Sep 23, 2003 |
| Priority date | — |
| Expiry date | Nov 20, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R33/56554
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A steady-state free precession (SSFP) sequence includes a large multiplicity of RF pulses (40) with a relatively short repeat time or interpulse interval (TR) on the order of 2-10 milliseconds. After applying the RF pulses for a period of about 3 T1, about 6 seconds, a steady-state is achieved. Thereafter, at least a phase-encode gradient (42) and a read gradient (44) are applied between each subsequent pair of adjoining RF pulses, a data line being generated during each read gradient pulse. For a 128 line image with a TR of 6 milliseconds, a set of data lines are generated in 768 milliseconds, about ¾ of a second. As the data lines are generated, a spectral offset is adjusted by continuously adjusting an RF phase of an RF transmitter (24) and an RF receiver (50), with N sets of data lines being generated over 360° of RF phase shift. Like corresponding data lines from each set offset an RF phase by 360°/N are combined and Fourier transformed into an image representation. In this manner, N complete data sets are collected at different spectral offsets without intervening delay intervals to reestablish the steady-state, i.e., in 9 seconds instead of 27 seconds (for N=4…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.