Patent US4884029A successfully refreshed from Google Patents.
US4884029A
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Quick imaging scheme utilizing differently phase encoded primary and stimulated echoes
Assignee: Philips Nuclear Medicine Inc
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Filing: 1988-09-12
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Granted: 1989-11-28
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Expires: 2008-09-12
Abstract
Abstract A magnetic resonance excitation pulse (50, 150, 250) is applied to excite resonance in selected dipoles in an examination region. A second radio frequency pulse (60, 160, 260) induces a primary echo which is phase encoded by a phase encode gradient (56, 156, 256) with a first phase encode angle. Optionally, an additional phase encode gradient (356) may be applied after the primary echo to remove the first phase encoding. A third radio frequency pulse (70, 170, 270) rotates the magnetization, typically 90°, to cause a stimulated echo (72, 172, 272) which is phase encoded in accordance with a second phase encode gradient (78, 178, 278). Optionally, another phase encode gradient pulse (378) may be applied after the stimulated echo to remove the second phase encoding. In the preferred embodiment, the first phase encoding is varied in steps from central phase encoding to a first preselected maximum phase encoding and the second phase encoding varies from about the central phase encoding to a second maximum of about the same magnitude as the first maximum but of the opposite polarity. In this manner, an interface between primary and secondary echo data is defined adjacent the central phase encode angle. The primary and stimulated echo data are corrected for discontinuities and reconstructed into an image representation. Redundant primary and stimulated echo data are collected adjacent the interface for comparison during the alignment.
Inventors
- 👤 William Sattin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 15:12
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/44; G01R33/48; G01R33/4818; G01R33/482; G01R33/50
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
87 words
A method of magnetic resonance imaging comprising: (a) exciting magnetic resonance in a subject; (b) inducing a primary echo with a first phase encoding and a stimulated echo with a second phase encoding, which second phase encoding is different from the first phase encoding; (c) collecting and summing primary and stimulated echo date; (d) repeating steps (a) through (c) for a plurality of phase encodings; and, (e) Fourier transforming the summed echo data to reconstruct a common image representation from the collected primary and stimulated echo data.
Claim 2
Independent Claim
87 words
A method of magnetic resonance imaging comprising: (a) exciting magnetic resonance in a subject; (b) inducing a primary echo with a first phase encoding and a stimulated echo with a second phase encoding, which second phase encoding is different from the first phase encoding; (c) collecting and summing primary and stimulated echo date; (d) repeating steps (a) through (c) for a plurality of phase encodings; and, (e) Fourier transforming the summed echo data to reconstruct a common image representation from the collected primary and stimulated echo data.
Claim 3
Independent Claim
95 words
A method of magnetic resonance imaging comprising: (a) exciting magnetic resonance in a subject; (b) inducing a primary echo with a first phase encoding; (c) removing the first phase encoding after the primary echo and prior to inducing a stimulated echo; (d) inducing stimulated echo with a second phase encoding, which second phase encoding is different from the first phase encoding; (e) collecting primary and stimulated echo data; (f) repeating steps (a) through (c) for a plurality of phase encoding; and, (g) reconstructing a common image representation from the collected primary and stimulated echo data.
Claim 4
Independent Claim
95 words
A method of magnetic resonance imaging comprising: (a) exciting magnetic resonance in a subject; (b) inducing a primary echo with a first phase encoding; (c) removing the first phase encoding after the primary echo and prior to inducing a stimulated echo; (d) inducing stimulated echo with a second phase encoding, which second phase encoding is different from the first phase encoding; (e) collecting primary and stimulated echo data; (f) repeating steps (a) through (c) for a plurality of phase encoding; and, (g) reconstructing a common image representation from the collected primary and stimulated echo data.
Claim 5
Dependent Claim
20 words
The method as set forth in claim 2 further including removing the second phase encoding subsequent to the stimulated echo.
Claim 6
Independent Claim
148 words
A method of magnetic resonance imaging comprising: (a) exciting magnetic resonance in a subject; (b) inducing a primary echo with a first phase encoding and a stimulated echo with a second phase encoding, which second phase encoding is different from the first phase encoding; (c) collecting primary and stimulated echo data; (d) repeating steps (a) through (c) for a plurality of phase encodings in which the first phase encoding is varied in steps generally between a central phase encoding and a first maximum phase encoding and the second phase encoding is varied generally between the central phase encoding and a second maximum phase encoding, the first and second phase encodings being of opposite polarity, such that there is a single interface between the primary and stimulated echo data adjacent the central phase encoding; and, (e) reconstructing a common image representation from the collected primary and stimulated echo data.
Claim 7
Independent Claim
148 words
A method of magnetic resonance imaging comprising: (a) exciting magnetic resonance in a subject; (b) inducing a primary echo with a first phase encoding and a stimulated echo with a second phase encoding, which second phase encoding is different from the first phase encoding; (c) collecting primary and stimulated echo data; (d) repeating steps (a) through (c) for a plurality of phase encodings in which the first phase encoding is varied in steps generally between a central phase encoding and a first maximum phase encoding and the second phase encoding is varied generally between the central phase encoding and a second maximum phase encoding, the first and second phase encodings being of opposite polarity, such that there is a single interface between the primary and stimulated echo data adjacent the central phase encoding; and, (e) reconstructing a common image representation from the collected primary and stimulated echo data.
Claim 8
Dependent Claim
57 words
The method as set forth in claim 4 further including phase encoding the primary echo with the second phase encoding steps and phase encoding the stimulated echo with the first phase encoding steps for a limited number of steps adjacent the central phase encoding such that redundant primary and stimulated echo data is generated adjacent the interface.
Claim 9
Dependent Claim
29 words
The method as set forth in claim 5 further including comparing the redundant data and adjusting at least one of the primary and stimulated echo data in accordance therewith.
Claim 10
Independent Claim
104 words
A method of magnetic resonance imaging comprising: (a) exciting magnetic resonance in a subject; (b) inducing a primary echo with a first phase encoding and a stimulated echo with a second phase encoding, which second phase encoding is different from the first phase encoding; (c) collecting primary and stimulated echo data; (d) repeating steps (a) through (c) for a plurality of phase encodings such that there is at least one interface between the primary and stimulated echo data; (e) matching the primary and stimulated echo data adjacent the interface; and (f) reconstructing a common image representation from the collected primary and stimulated echo data.
Claim 11
Independent Claim
104 words
A method of magnetic resonance imaging comprising: (a) exciting magnetic resonance in a subject; (b) inducing a primary echo with a first phase encoding and a stimulated echo with a second phase encoding, which second phase encoding is different from the first phase encoding; (c) collecting primary and stimulated echo data; (d) repeating steps (a) through (c) for a plurality of phase encodings such that there is at least one interface between the primary and stimulated echo data; (e) matching the primary and stimulated echo data adjacent the interface; and (f) reconstructing a common image representation from the collected primary and stimulated echo data.
Claim 12
Independent Claim
162 words
A method of magnetic resonance imaging comprising: (a) applying a first radio frequency pulse to excite magnetic resonance; (b) applying a second radio frequency pulse to rotate a first component of the magnetic resonance into the transverse plane and inducing a primary magnetic resonance echo; (c) phase encoding the first component with a first phase encode angle; (d) applying at least a third ration frequency pulse to rotate the first magnetization component out of the transverse plane and rotate a second magnetization component into the transverse plane and inducing a stimulated magnetic response echo; (e) phase encoding the second magnetization component with a second phase encode angle which is different from the first phase encode angle; (f) collecting and summing primary and stimulated echo data during the primary and stimulated echoes; (g) repeating steps (a) through (f) for a plurality of first and second phase encode angles; and, (h) reconstructing a single image representation from the summed primary and stimulated echo data.
Claim 13
Independent Claim
162 words
A method of magnetic resonance imaging comprising: (a) applying a first radio frequency pulse to excite magnetic resonance; (b) applying a second radio frequency pulse to rotate a first component of the magnetic resonance into the transverse plane and inducing a primary magnetic resonance echo; (c) phase encoding the first component with a first phase encode angle; (d) applying at least a third ration frequency pulse to rotate the first magnetization component out of the transverse plane and rotate a second magnetization component into the transverse plane and inducing a stimulated magnetic response echo; (e) phase encoding the second magnetization component with a second phase encode angle which is different from the first phase encode angle; (f) collecting and summing primary and stimulated echo data during the primary and stimulated echoes; (g) repeating steps (a) through (f) for a plurality of first and second phase encode angles; and, (h) reconstructing a single image representation from the summed primary and stimulated echo data.
Claim 14
Dependent Claim
85 words
The method as set forth in claim 8 wherein the first phase encode gradient is repeated in steps from about a central phase encode angle to a first preselected phase encode angle and wherein the second phase encode gradient is applied in steps from about the central phase encode angle to a second preselected phase encode angle of an opposite polarity to the preselected phase encode angle, whereby a single interface occurs adjacent the central phase encode angle between the primary and stimulated echo data.
Claim 15
Dependent Claim
20 words
The method as set forth in claim 9 further including matching the primary and stimulated echo data along the interface.
Claim 16
Dependent Claim
51 words
The method as set forth in claim 10 further including collecting redundant primary and stimulated echo data adjacent the interface and wherein the matching step includes comparing the redundant primary and stimulated echo data and adjusting at least one of the primary and stimulated echo data in accordance with the comparison.
Claim 17
Independent Claim
207 words
A method of magnetic resonance imaging comprising: (a) applying a first radio frequency pulse to excite magnetic resonance; (b) applying a second radio frequency pulse to rotate a first component of the magnetic resonance into the transverse plane and inducing a primary magnetic resonance echo; (c) phase encoding the first component with a first phase encode gradient; (d) applying a first additional phase encode gradient of equal magnitude and opposite polarity to the first phase encode gradient after the primary echo; (e) applying a third radio frequency pulse to rotate the first magnetization component out of the transverse plane and rotate a second magnetization component into the transverse plane inducing a stimulated magnetic response echo; (f) phase encoding the second magnetization component with a second phase encode gradient which is different from the first phase encode gradient; (g) applying a second additional phase encode gradient after the stimulated echo which has the same magnitude and opposite polarity as the second phase encode gradient; (h) collecting primary and stimulated echo data during the primary and stimulated echoes; (i) repeating steps (a) through (h) for a plurality of first and second phase encode angles; and, (j) reconstructing a single image representation from the summed primary and stimulated echo data.
Claim 18
Independent Claim
207 words
A method of magnetic resonance imaging comprising: (a) applying a first radio frequency pulse to excite magnetic resonance; (b) applying a second radio frequency pulse to rotate a first component of the magnetic resonance into the transverse plane and inducing a primary magnetic resonance echo; (c) phase encoding the first component with a first phase encode gradient; (d) applying a first additional phase encode gradient of equal magnitude and opposite polarity to the first phase encode gradient after the primary echo; (e) applying a third radio frequency pulse to rotate the first magnetization component out of the transverse plane and rotate a second magnetization component into the transverse plane inducing a stimulated magnetic response echo; (f) phase encoding the second magnetization component with a second phase encode gradient which is different from the first phase encode gradient; (g) applying a second additional phase encode gradient after the stimulated echo which has the same magnitude and opposite polarity as the second phase encode gradient; (h) collecting primary and stimulated echo data during the primary and stimulated echoes; (i) repeating steps (a) through (h) for a plurality of first and second phase encode angles; and, (j) reconstructing a single image representation from the summed primary and stimulated echo data.
Claim 19
Dependent Claim
113 words
A magnetic resonance imaging apparatus comprising: means for generating a generally uniform main magnetic field through an image region; a radio frequency means for selectively inducing magnetic resonance of selected dipoles of a subject in the examination region and for selectively causing primary and stimulated echoes; a phase encoding means for phase encoding the primary and stimulated echoes with different phase angles; a receiver means for receiving primary and stimulated echo data during the primary and stimulated echoes; a correcting means for adjusting at least one of the primary and stimulated echo data to correct for discontinuities; a transform means for transforming the aligned primary and stimulated echo data into an image representation.
Claim 20
Dependent Claim
113 words
A magnetic resonance imaging apparatus comprising: means for generating a generally uniform main magnetic field through an image region; a radio frequency means for selectively inducing magnetic resonance of selected dipoles of a subject in the examination region and for selectively causing primary and stimulated echoes; a phase encoding means for phase encoding the primary and stimulated echoes with different phase angles; a receiver means for receiving primary and stimulated echo data during the primary and stimulated echoes; a correcting means for adjusting at least one of the primary and stimulated echo data to correct for discontinuities; a transform means for transforming the aligned primary and stimulated echo data into an image representation.
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) | 1992-11-27 | 1993-05-29 | 1993-11-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-11-27 | 1997-05-29 | 1997-11-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-11-27 | 2001-05-29 | 2001-11-28 | $7700.00 | Window Closed / Lapsed |