Electricity: measuring and testing – Particle precession resonance – Using a nuclear resonance spectrometer system
Reexamination Certificate
2006-08-08
2006-08-08
Shrivastav, Brij B (Department: 2859)
Electricity: measuring and testing
Particle precession resonance
Using a nuclear resonance spectrometer system
C324S307000
Reexamination Certificate
active
07088099
ABSTRACT:
Spatial encoding in magnetic resonance imaging (MRI) techniques is achieved by sampling the signal as a function of time in the presence of magnetic field gradients, e.g., X, Y, and Z gradients. The gradient magnets have in the past been assumed to generate a linear gradient, and typical image reconstruction techniques have relied upon this assumption. However, to achieve high speed performance, gradient magnets often sacrifice linearity for speed. This non-linearity, in turn, results in distorted images, the distortion often being sufficiently large to compromise the usefulness of MRI images for stereotaxy or longitudinal studies, where precise volumetric information is required. The disclosure provides practical methods for correcting distorted images resulting from such non-linearity in the gradient fields, as well as distortions resulting from translational, rotational, and/or winding/design errors in the field generating devices. The methods employ spherical harmonic expansions of the gradient fields and fast Fourier transform techniques to provide well-corrected images without undue computational burdens.
REFERENCES:
patent: 5260116 (1993-11-01), Hamanaka et al.
patent: 5289127 (1994-02-01), Doddrell et al.
patent: 6252401 (2001-06-01), Werthner et al.
patent: 6501273 (2002-12-01), Krieg et al.
patent: 6636756 (2003-10-01), Zhu
patent: 2002/0093334 (2002-07-01), Zhu
Bakker CJ, Moerland MA, Bhagwandien R, Beersma R. “Analysis of machine-dependent and object-induced geometric distortion in 2DFT MR imaging.”Magn Reson Imaging. 1992;10(4):597-608.
Chang H, Fitzpatrick JM. “A technique for accurate magnetic resonance imaging in the presence of field inhomogeneities.”IEEE Trans. Med. Imaging, 11: 319-329, 1992.
Chen NK, Wyrwicz AM. “Optimized distortion corretcion technique for echo planar imaging.”Magn Reson Med. Mar. 2001;45(3):525-8.
Collins DL, Evans AC. “Animal: validation and applications of non-linear registration-based segmentation.”Int J Pattern Recog and Art Intell, 1997: 11:1271-1293.
Cusack R, Brett M, Osswald K. “An evaluation of the use of magnetic field maps to undistort echo-planar images.”Neuroimage. Jan. 2003;18(1):127-42.
Eccles CD, Crozier S, Westphal M, Doddrell DM. “Temporal spherical-harmonic expansion and compensation of eddy-current fields produced by gradient pulses.”Journal of Magnetic Resonance, A 103: 135-141, 1993.
Fransson A, Andreo P, Potter R. “Aspects of MR image distortions in radiotherapy treatment planning.”Strahlenther Onkol. Feb. 2001;177(2):59-73.
Langlois S, Desvignes M, Constans JM, Revenu M. “MRI geometric distortion: a simple approach to correcting the effects of non-linear gradient fields.”J Magn Reson Imaging. Jun. 1999;9(6):821-31.
Liu H, “An efficient geometric image distortion correction method for a biplanar planar gradient coil.”Magnetic Resonance Materials in Physics, Biology and Medicine, 10: 75-79, 2000.
Maurer CR Jr, Aboutanos GB, Dawant BM, Gadamsetty S, Margolin RA, Maciunas RJ, Fitzpatrick JM. “Effect of geometrical distortion correction in MR on image registration accuracy.”J Comput Assist Tomogr. Jul.-Aug. 1996;20(4):666-79.
Mizowaki T, Nagata Y, Okajima K, Murata R, Yamamoto M, Kokubo M, Hiraoka M, Abe M. “Development of an MR simulator: experimental verification of geometric distortion and clinical application.”Radiology. Jun. 1996;199(3):855-60.
Mizowaki T, Nagata Y, Okajima K, Kokubo M, Negoro Y, Araki N, Hiraoka M. “Reproducibility of geometric distortion in magnetic resonance imaging based on phantom studies.”Radiother Oncol. Nov. 2000;57(2):237-42.
Moerland MA, Beersma R, Bhagwandien R, Wijrdeman HK, Bakker CJ. “Analysis and correction of geometric distortions in 1.5 T magnetic resonance images for use in radiotherapy treatment planning.”Phys Med Biol. Oct. 1995;40(10):1651-1664.
Schad L, Lott S, Schmitt F, Sturm V, Lorenz WJ. “Correction of spatial distortion in MR imaging: a prerequisite for accurate stereotaxy.”J Comput Assist Tomogr. May-Jun. 1987;11(3):499-505.
Schad LR, Ehricke HH, Wowra B, Layer G, Engenhart R, Kauczor HU, Zabel HJ, Brix G, Lorenz WJ. “Correction of spatial distortion in magnetic resonance angiography for radiosurgical treatment planning of cerebral arteriovenous malformations.”Magn Reson Imaging. 1992;10(4):609-21.
Tanner SF, Finnigan DJ, Khoo VS, Mayles P, Dearnaley DP, Leach MO. “Radiotherapy planning of the pelvis using distortion corrected MR images: the removal of system distortions.”Phys Med Biol. Aug. 2000;45(8):2117-32.
Woo JH, Kim YS, Kim SI. “The correction of MR images distortion with phantom studies.”Stud Health Technol Inform. 1999;62:388-9.
Yu C, Petrovich Z, Apuzzo ML, Luxton G. “An image fusion study of the geometric accuracy of magnetic resonance imaging with the Leksell stereotactic localization system.”J Appl Clin Med Phys. 2001 Winter;2(1):42-50.
Doddrell David M.
Zhao Huawei
Klee Maurice M.
Shrivastav Brij B
The University of Queensland
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