Magnetic resonance imaging with phase encoded chemical shift correction
US4720679A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 31, 1985 |
| Grant date | Jan 19, 1988 |
| Priority date | — |
| Expiry date | Dec 31, 2005 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R33/56527
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A shimming magnetic field control (22) causes shimming magnetic fields for improving uniformity of a main magnetic field generated by main magnets (10). A resonance excitation control (32) selectively applies a resonance excitation pulse (34) and inversion pulse (36) for inverting the spin magnetization of water and lipid dipoles. A phase sensitive detector (30) selectively receives resonance signal components which are transformed by a transform algorithm (70) into a real image (72) and an imaginary image (74). The inversion pulse (36) is shifted by a time such that the water and lipid spin magnetizations are out of phase by a predetermined amount. With a 90.degree. phase difference, the real image represents water and the imaginary represents lipid. A phase image (80) is derived from a reference image pair (76, 78). A phase unwrap circuit (82) removes ambiguities attributable to the spin magnetizations becoming dephased by multiples of 2.pi. to create a phase map (84). A shim adjustment circuit (94) measures uniformity of the phase map and causes the shim field control circuit (22) to adjust the shimming magnetic fields to optimize the measured uniformity. The phase map is invers…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.