Chemical shift imaging with spectrum modeling
US5994902A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 9, 1998 |
| Grant date | Nov 30, 1999 |
| Priority date | — |
| Expiry date | Apr 9, 2018 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T436/24
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Chemical shift imaging with spectrum modeling (CSISM) models the general chemical shift spectrum as a system with N distinct peaks with known resonant frequencies and unknown amplitudes. Based on the N peak spectrum model, a set of nonlinear complex equations is set up that contains N+1 unknowns of two kdnds: the magnitudes of the N peaks, and a phasor map caused by main magnetic field inhomogeneity. Using these equations, the timing parameters for shifting the 180.degree. RF refocusing pulses for acquiring spin-echo images are optimally chosen. Corresponding timing parameters for other pulse sequences can also be optimized similarly. Using the chosen timing parameters, a plurality of images are acquired. Next, acquired image data are automatically processed to solve the complex linear equations. First, the phasor map is found by fitting various phasor map values over a small number of pixels, or "seeds", that are picked sparsely in a field of view. Second, from the original "seeds", the region of pixels that are picked to find the best-fit phasor map is grown into the entire field of view, based on a predetermined phase difference between the original seed and a neighboring pixel.…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.