Method and apparatus for correcting spatial distortion in magnetic resonance images due to magnetic field inhomogeneity including inhomogeneity due to susceptibility variations
US5351006A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 12, 1993 |
| Grant date | Sep 27, 1994 |
| Priority date | — |
| Expiry date | Oct 12, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R33/56527
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An in-vivo correction method for the non-linear, shape dependent spatial distortion in MR images due to magnetic field inhomogeneity including inhomogeneity due to susceptibility variations is disclosed. Geometric distortion at the air/tissue and tissue/bone interfaces before and after the correction is quantified using a phantom. The results are also compared to the "distortion-free" CT images of the same phantom. Magnetic susceptibility of cortical cattle bone was measured using a SQUID magnetometer and found to be -8.86 ppm which is quite similar to that of tissue (-9 ppm). The distortion at the bone/tissue boundary was negligible while that at the air/tissue boundary created displacements of about 2.0 mm with a1.5T main magnetic field and a 3.13 mT/m gradient field, a significant value if MR images are used to localize targets with the high accuracy expected for stereotaxic surgery. The correction method reduces the errors to at least the same level of accuracy as CT.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.