US8067936B2
Active / In Force
US
⏱️ 3.7 years remaining
Frequency swept excitation for magnetic resonance
Assignee: University of Minnesota System
•
Filing: 2010-08-04
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Granted: 2011-11-29
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Expires: 2030-08-04
Abstract
Abstract A method of magnetic resonance is provided that uses a frequency swept excitation wherein the acquired signal is a time domain signal is provided. In one embodiment, the method comprises, applying a sweeping frequency excitation and acquiring a time domain signal. The sweeping frequency excitation has a duration and is configured to sequentially excite isochromats having different resonant frequencies. Acquisition of the time domain signal is done during the duration of the sweeping frequency excitation. The time domain signal is based on evolution of the isochromats.
Inventors
- 👤 Michael G. Garwood
- 👤 Djaudat S. Idiyatullin
- 👤 Curtis A. Corum
- 👤 Steen Moeller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 11:57
CPC Classifications
G; G01; G01N; G01N24/00; G01N24/10; G01R; G01R33/00; G01R33/20; G01R33/44; G01R33/441; G01R33/446; G01R33/46; G01R33/4616; G01R33/48; G01R33/4816; G01R33/54; G01N24/08; G01N24/081
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
82 words
A method comprising: using a magnetic resonance scanner to apply an excitation sequence to a specimen, the excitation sequence including a series of repeated pulses, each pulse having a pulse duration less than a repetition time for the repeated pulses, and each pulse having a plurality of alternating excitation segments and quiescent segments and each pulse modulated in frequency or modulated in phase; acquiring a response signal simultaneous with application of the excitation sequence; and generating an image using the response signal.
Claim 2
Independent Claim
82 words
A method comprising: using a magnetic resonance scanner to apply an excitation sequence to a specimen, the excitation sequence including a series of repeated pulses, each pulse having a pulse duration less than a repetition time for the repeated pulses, and each pulse having a plurality of alternating excitation segments and quiescent segments and each pulse modulated in frequency or modulated in phase; acquiring a response signal simultaneous with application of the excitation sequence; and generating an image using the response signal.
Claim 3
Dependent Claim
19 words
The method of claim 1 wherein radio frequency power of the excitation sequence is off during a quiescent segment.
Claim 4
Dependent Claim
15 words
The method of claim 1 wherein the frequency of the excitation sequence is swept linearly.
Claim 5
Dependent Claim
14 words
The method of claim 1 wherein the excitation sequence includes a hyperbolic secant pulse.
Claim 6
Dependent Claim
15 words
The method of claim 1 wherein the excitation sequence includes a truncated hyperbolic secant pulse.
Claim 7
Dependent Claim
16 words
The method of claim 1 further including applying a magnetic field gradient during the excitation sequence.
Claim 8
Dependent Claim
31 words
The method of claim 6 wherein the excitation sequence includes a swept frequency configured to excite the specimen in a time sequential manner along a direction of the magnetic field gradient.
Claim 9
Dependent Claim
15 words
The method of claim 6 further including modulating an amplitude of the magnetic field gradient.
Claim 10
Dependent Claim
24 words
The method of claim 8 wherein modulating the amplitude of the magnetic field gradient is at a selected rate to maintain a steady state.
Claim 11
Dependent Claim
25 words
The method of claim 6 wherein a difference between the pulse duration and the repetition time exceeds a time for setting the magnetic field gradient.
Claim 12
Dependent Claim
20 words
The method of claim 1 wherein the excitation sequence is configured to coincide with a motion corresponding to the specimen.
Claim 13
Dependent Claim
22 words
The method of claim 1 wherein generating the image includes forming a plurality of projections, each projection corresponding to the response signal.
Claim 14
Independent Claim
65 words
A method comprising: using a magnetic resonance scanner to provide an excitation signal to a specimen, the excitation signal including a plurality of pulses, each pulse having modulated excitation segments separated by quiescent segments, the excitation segments modulated in phase or modulated in frequency; acquiring a response signal corresponding to relaxation of isochromats of the specimen; and generating an output based on the response signal.
Claim 15
Independent Claim
65 words
A method comprising: using a magnetic resonance scanner to provide an excitation signal to a specimen, the excitation signal including a plurality of pulses, each pulse having modulated excitation segments separated by quiescent segments, the excitation segments modulated in phase or modulated in frequency; acquiring a response signal corresponding to relaxation of isochromats of the specimen; and generating an output based on the response signal.
Claim 16
Dependent Claim
19 words
The method of claim 13 wherein each pulse has a duration and the acquiring occurs simultaneous with the duration.
Claim 17
Dependent Claim
16 words
The method of claim 13 further including applying a magnetic gradient simultaneous with the excitation signal.
Claim 18
Dependent Claim
15 words
The method of claim 15 wherein applying the magnetic gradient includes applying a modulated gradient.
Claim 19
Dependent Claim
30 words
The method of claim 13 wherein the excitation signal includes a first frequency swept signal having a first direction and includes a second frequency swept signal having a second direction.
Claim 20
Dependent Claim
14 words
The method of claim 17 wherein the first direction is opposite the second direction.
Claim 21
Dependent Claim
23 words
The method of claim 13 wherein the excitation signal includes a carrier frequency, and further including varying the carrier frequency to introduce jitter.
Claim 22
Dependent Claim
61 words
The method of claim 13 wherein the excitation signal includes a first sequence and a second sequence, and further including providing a first gradient during the first sequence and providing a second gradient during the second sequence, wherein at least one of the first gradient and the second gradient is configured to provide a gradient-echo, a spin-echo, or a simulated echo.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2014-11-28 | 2015-05-30 | 2015-11-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2018-11-28 | 2019-05-30 | 2019-11-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2022-11-28 | 2023-05-30 | 2023-11-29 | $7700.00 | Window Closed / Lapsed |