US7777484B2
Active / In Force
US
⏱️ 1.9 years remaining
Frequency swept excitation for magnetic resonance
Assignee: University of Minnesota System
•
Filing: 2008-09-15
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Granted: 2010-08-17
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Expires: 2028-09-15
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 Garwood
- 👤 Djaudat S. Idiyatullin
- 👤 Curt Corum
- 👤 Steen Moeller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 14:41
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: 25
Claim 1
Independent Claim
77 words
A method comprising: using a magnetic resonance scanner to excite a specimen with a sweeping frequency excitation having a plurality of alternating excitation segments and quiescent segments, the excitation segments modulated according to at least one of a phase modulation function and a frequency modulation function; applying at least one functional pulse; acquiring a time domain signal from the specimen based on resonance during a plurality of the quiescent segments; and processing the acquired time domain signal.
Claim 2
Independent Claim
77 words
A method comprising: using a magnetic resonance scanner to excite a specimen with a sweeping frequency excitation having a plurality of alternating excitation segments and quiescent segments, the excitation segments modulated according to at least one of a phase modulation function and a frequency modulation function; applying at least one functional pulse; acquiring a time domain signal from the specimen based on resonance during a plurality of the quiescent segments; and processing the acquired time domain signal.
Claim 3
Dependent Claim
24 words
The method of claim 1 , wherein the at least one functional pulse is applied before exciting a specimen with a sweeping frequency excitation.
Claim 4
Dependent Claim
27 words
The method of claim 1 , wherein effects of the functional pulse are localized in one or more spatial dimensions in the presence of a field gradient.
Claim 5
Dependent Claim
24 words
The method of claim 1 , wherein the at least one functional pulse is applied after exciting a specimen with a sweeping frequency excitation.
Claim 6
Dependent Claim
21 words
The method of claim 1 , wherein the at least one functional pulse establishes a steady or oscillating spatial magnetization state.
Claim 7
Dependent Claim
18 words
The method of claim 1 , further comprising applying a gradient during the at least one functional pulse.
Claim 8
Dependent Claim
20 words
The method of claim 6 , wherein a subset of gradients is used during the at least one functional pulse.
Claim 9
Dependent Claim
15 words
The method of claim 1 , wherein the at least one functional pulse prepares magnetization.
Claim 10
Dependent Claim
15 words
The method of claim 1 , wherein the at least one functional pulse spoils magnetization.
Claim 11
Dependent Claim
15 words
The method of claim 1 , wherein the at least one functional pulse restores magnetization.
Claim 12
Dependent Claim
25 words
The method of claim 1 , wherein the at least one functional pulse suppresses or enhances magnetization based on T2, T1, T1ρ, T2ρ, or diffusion.
Claim 13
Dependent Claim
29 words
The method of claim 1 , wherein processing comprises performing conjugate multiplication of a Fourier transform of the time domain signal and a Fourier transform of the frequency excitation.
Claim 14
Dependent Claim
31 words
The method of claim 12 , wherein at least one of the Fourier transformed signal and Fourier transformed excitation are windowed or filtered before processing and wherein processing comprises conjugate multiplication.
Claim 15
Dependent Claim
16 words
The method of claim 1 , further comprising applying a field gradient to create an image.
Claim 16
Dependent Claim
17 words
The method of claim 14 , further comprising reconstructing the image based on the time domain signal.
Claim 17
Dependent Claim
28 words
The method of claim 15 , further comprising adjusting the time domain signal with a constant, linearly, quadratic, or higher order phase correction prior to reconstructing the image.
Claim 18
Dependent Claim
13 words
The method of claim 15 , further comprising deleting pulse contamination during reconstruction.
Claim 19
Dependent Claim
34 words
The method of claim 1 , wherein the acquired time domain signal has a poor quality segment and or edges, and further comprising eliminating the poor quality segment or edges before correlation or deconvolution.
Claim 20
Dependent Claim
19 words
The method of claim 1 , wherein processing the acquired time domain signal comprises applying a phase consistency algorithm.
Claim 21
Dependent Claim
18 words
The method of claim 1 , wherein processing the acquired time domain signal comprises processing complex phased projections.
Claim 22
Dependent Claim
18 words
The method of claim 1 , wherein processing the acquired time domain signal comprises processing real phased projections.
Claim 23
Dependent Claim
38 words
The method of claim 1 , wherein processing the acquired time domain signal comprises applying a cone beam resampling algorithm to correct between expected angles of projections and actual projections by estimating new projections from different measured projections.
Claim 24
Dependent Claim
17 words
The method of claim 1 , wherein the sweeping frequency excitation is located in a radiofrequency spectrum.
Claim 25
Dependent Claim
16 words
The method in claim 1 , wherein the sweeping frequency excitation is in an optical spectrum.
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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) | 2013-08-16 | 2014-02-15 | 2014-08-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2017-08-16 | 2018-02-15 | 2018-08-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2021-08-16 | 2022-02-15 | 2022-08-17 | $7700.00 | Window Closed / Lapsed |