US6310478B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic reasonance tomography apparatus and method in the form of a pulse sequence for operating same
Assignee: Siemens AG
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Filing: 2000-01-18
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Granted: 2001-10-30
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Expires: 2020-01-18
Abstract
Abstract In a method in the form of a pulse sequence for ultra-rapid nuclear magnetic resonance tomography and a magnetic resonance tomography apparatus operating according to the method, image data are obtained in a pulse sequence wherein the magnetization vector oscillates by an angle ±α in the steady stage, with a being smaller then 90°. This is the case, for example, given a SSFP sequence. RF pulse train composed of a number of RF pulses is respectively emitted during one-half of a readout gradient. A bipolar readout gradient pulse train can be employed, with an RF pulse train being emitted during a negative half of the readout gradient pulse train.
Inventors
- 👤 Oliver Heid
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 23:31
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/44; G01R33/48; G01R33/54; G01R33/56; G01R33/561; G01R33/5613
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
102 words
A method for rapidly obtaining image data in magnetic resonance tomography comprising the steps of: subjecting an examination subject to a pulse sequence which causes a nuclear magnetization vector within said examination subject to oscillate between angles ±α in a steady state, wherein α is less than 90°; in said pulse sequence, emitting a bipolar readout gradient, including a positive half and a negative half, and reading out nuclear magnetic resonance signals from said examination subject during said bipolar readout gradient; and in said pulse sequence, emitting at least one RF excitation pulse during each negative half of said bipolar readout gradient.
Claim 2
Independent Claim
102 words
A method for rapidly obtaining image data in magnetic resonance tomography comprising the steps of: subjecting an examination subject to a pulse sequence which causes a nuclear magnetization vector within said examination subject to oscillate between angles ±α in a steady state, wherein α is less than 90°; in said pulse sequence, emitting a bipolar readout gradient, including a positive half and a negative half, and reading out nuclear magnetic resonance signals from said examination subject during said bipolar readout gradient; and in said pulse sequence, emitting at least one RF excitation pulse during each negative half of said bipolar readout gradient.
Claim 3
Dependent Claim
24 words
A method as claimed in claim 1 comprising emitting a plurality of RF excitation pulses during each negative half of said bipolar readout gradient.
Claim 4
Dependent Claim
17 words
A method as claimed in claim 1 comprising amplitude modulating said at least one RF excitation pulse.
Claim 5
Dependent Claim
17 words
A method as claimed in claim 1 comprising phase modulating said at least one RF excitation pulse.
Claim 6
Dependent Claim
20 words
A method as claimed in claim 1 comprising amplitude modulating and phase modulating said at least one RF excitation pulse.
Claim 7
Dependent Claim
44 words
A method as claimed in claim 1 comprising emitting a plurality of switched gradients in said pulse sequence with gradient switching of said plurality of gradients being completely rephasing in all spatial directions between each emission of said at least one RF excitation pulse.
Claim 8
Dependent Claim
94 words
A method as claimed in claim 1 comprising, during each negative half of said bipolar readout gradient, emitting a first RF excitation pulse train comprised of a plurality of RF pulses and emitting a second RF excitation pulse train comprised of a plurality of RF pulses, said first RF excitation pulse train causing magnetization in a z-direction of an x, y, z coordinate system, arising from a preceding RF excitation pulse train, to be deflected into an x, y plane, and said second RF excitation pulse train rotating said magnetization back into said z-direction.
Claim 9
Dependent Claim
127 words
A magnetic resonance tomography apparatus comprising: a scanner having an RF coil and at least one gradient coil for subjecting an examination subject to a pulse sequence which causes a nuclear magnetization vector within said examination subject to oscillate between angles ±α in a steady state, wherein α is less than 90°; a controller connected to said at least one gradient coil for producing, in said pulse sequence, a bipolar readout gradient, including a positive half and a negative half, for reading out nuclear magnetic resonance signals from said examination subject during said bipolar readout gradient; and said controller being connected to said RF coil for producing, in said pulse sequence, emitting at least one RF excitation pulse during each negative half of said bipolar readout gradient.
Claim 10
Dependent Claim
127 words
A magnetic resonance tomography apparatus comprising: a scanner having an RF coil and at least one gradient coil for subjecting an examination subject to a pulse sequence which causes a nuclear magnetization vector within said examination subject to oscillate between angles ±α in a steady state, wherein α is less than 90°; a controller connected to said at least one gradient coil for producing, in said pulse sequence, a bipolar readout gradient, including a positive half and a negative half, for reading out nuclear magnetic resonance signals from said examination subject during said bipolar readout gradient; and said controller being connected to said RF coil for producing, in said pulse sequence, emitting at least one RF excitation pulse during each negative half of said bipolar readout gradient.
Claim 11
Dependent Claim
34 words
A magnetic resonance tomography apparatus as claimed in claim 8 wherein said controller caused said RF coil to emit a plurality of RF excitation pulses during each negative half of said bipolar readout gradient.
Claim 12
Dependent Claim
22 words
A magnetic resonance tomography apparatus as claimed in claim 8 comprising means for amplitude modulating said at least one RF excitation pulse.
Claim 13
Dependent Claim
22 words
A magnetic resonance tomography apparatus as claimed in claim 8 comprising means for phase modulating said at least one RF excitation pulse.
Claim 14
Dependent Claim
25 words
A magnetic resonance tomography apparatus as claimed in claim 8 comprising means for amplitude modulating and phase modulating said at least one RF excitation pulse.
Claim 15
Dependent Claim
57 words
A magnetic resonance tomography apparatus as claimed in claim 8 wherein said controller causes said at least one gradient coil to emit a plurality of switched gradients in said pulse sequence with gradient switching of said plurality of gradients being completely rephasing in all spatial directions between each emission of said at least one RF excitation pulse.
Claim 16
Dependent Claim
105 words
A magnetic resonance tomography apparatus as claimed in claim 8 wherein said controller caused said RF coil, during each negative half of said bipolar readout gradient, to emit a first RF excitation pulse train comprised of a plurality of RF pulses and to emit a second RF excitation pulse train comprised of a plurality of RF pulses, said first RF excitation pulse train causing magnetization in a z-direction of an x, y, z coordinate system, arising from a preceding RF excitation pulse train, to be deflected into an x, y plane, and said second RF excitation pulse train rotating said magnetization back into said z-direction.
References Cited (Backward Citations)
US6034528A
Cited
US5541514A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2004-10-29 | 2005-04-30 | 2005-10-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-10-29 | 2009-04-30 | 2009-10-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-10-29 | 2013-04-30 | 2013-10-30 | $7700.00 | Window Closed / Lapsed |