US5200700A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Reduction of NMR artifacts caused by time varying linear geometric distortion
Assignee: General Electric Co
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Filing: 1990-11-30
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Granted: 1993-04-06
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Expires: 2010-11-30
Abstract
Abstract NMR image data acquired from a human subject is corrected for view-to-view motion caused by respiration. As each view is acquired the position of the subject is also measured to indicate the distance of the anterior abdominal wall from a reference position. The acquired NMR image data is corrected using the associated measured distances and a simplified model of the motion.
Inventors
- 👤 Gary H. Glover
- 👤 Stephen W. Flax
- 👤 Ann Shimakawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 00:36
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/44; G01R33/48; G01R33/54; G01R33/56; G01R33/567; G01R33/5673; G01R33/5676
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
134 words
A method for correcting a set of NMR image data comprised of a plurality of digitized NMR signals that are acquired over a period of time during which the subject moves due to respiration, the steps comprising: (a) measuring the position of the subject as each digitized NMR signal is acquired; (b) calculating a motion value (ΔY) for each digitized NMR signal which indicates the position of the subject with respect to a reference position; (c) calculating a magnification factor m(V) for each motion value (ΔY) which is proportional to the motion value (ΔY) and a distance from a stationary point in the subject; (d) correcting each digitized NMR signal in the NMR image data set using an associated magnification factor m(V); and, (e) reconstructing an image using the corrected NMR image data set.
Claim 2
Independent Claim
134 words
A method for correcting a set of NMR image data comprised of a plurality of digitized NMR signals that are acquired over a period of time during which the subject moves due to respiration, the steps comprising: (a) measuring the position of the subject as each digitized NMR signal is acquired; (b) calculating a motion value (ΔY) for each digitized NMR signal which indicates the position of the subject with respect to a reference position; (c) calculating a magnification factor m(V) for each motion value (ΔY) which is proportional to the motion value (ΔY) and a distance from a stationary point in the subject; (d) correcting each digitized NMR signal in the NMR image data set using an associated magnification factor m(V); and, (e) reconstructing an image using the corrected NMR image data set.
Claim 3
Dependent Claim
65 words
The method as recited in claim 1 in which the correction of each digitized NMR signal using the associated magnification factor m(V) includes: (a) fitting a curve to the digitized NMR signal; (b) sampling the curve at intervals determined by the magnification factor m(V) to produce a corrected digitized NMR signal; and, (c) dividing each corrected digitized NMR signal by its associated magnification factor m(V).
Claim 4
Dependent Claim
32 words
The method as recited in claim 2 in which each corrected digitized NMR signal is multiplied by a phase factor which is determined by the value of its associated magnification factor m(V).
Claim 5
Dependent Claim
118 words
The method as recited in claim 1 in which the NMR image data set is stored as an array in which each digitized NMR signal is a row of elements and the correction of each digitized NMR signal using the associated magnification factor m(V) includes: (di) fitting a curve to the digitized NMR signal values in a column of the array; (dii) sampling the curve at intervals determined by the magnification factors m(V) associated with the respective elements in the column to produce a column of corrected digitized NMR signal values; (diii) dividing each corrected digitized NMR signal value by its associated magnification factor m(V); and, (div) repeating steps (di) through (diii) for each column in the array.
Claim 6
Dependent Claim
36 words
The method as recited in claim 4 in which each corrected digitized NMR signal value in the array is multiplied by a phase factor which is determined by the value of its associated magnification factor m(V).
Claim 7
Dependent Claim
69 words
The method as recited in claim 1 in which the position of the subject is measured as each digitized NMR signal is acquired by: (ai) performing a motion pulse sequence along with each image data pulse sequence to acquire a position NMR signal; (aii) performing a Fourier transformation on the acquired position NMR signal; and (aiii) detecting the position of a characteristic feature in the transformed position NMR signal.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-04-05 | 1996-10-05 | 1997-04-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-04-05 | 2000-10-05 | 2001-04-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-04-05 | 2004-10-05 | 2005-04-06 | $7700.00 | Window Closed / Lapsed |