Detecting Spin Perturbations Using Magnetic Resonance Imaging
First Claim
1. A method of magnetic resonance imaging (MRI), comprising:
- magnetizing a sample comprising nuclear spins using a principle magnetic field generated external to the sample;
applying to the sample a periodic pulse sequence comprising a plurality of radio frequency (rf) pulses and a plurality of recovery times between the rf pulses, wherein the pulse sequence is configured to generate, in the presence of a time-dependent magnetic field perturbation in the sample, a sequence of at least three different steady states of magnetization in the sample during each period of the pulse sequence; and
processing a magnetic resonance signal acquired from the sample when under application of the periodic pulse sequence to identify characteristics of the magnetic field perturbation.
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Accused Products
Abstract
Implementations and examples of systems, apparatus and techniques for using magnetic resonance imaging to measure spin perturbations. In one implementation, a sample containing nuclear spins is magnetized using a principle magnetic field generated external to the sample. A periodic pulse sequence is applied to the sample. The pulse sequence includes multiple radio frequency (rf) pulses and multiple recovery times between the rf pulses. The pulse sequence is configured to generate, in the presence of a magnetic field perturbation, a sequence of multiple different steady states of magnetization in the sample during each period of the pulse sequence. A magnetic resonance signal acquired from the sample is processed to identify characteristics of a magnetic field perturbation in the sample. In some implementations, processing the signal to identify characteristics of a magnetic field perturbation in the sample includes processing the signal to identify characteristics of an electric current in the sample.
30 Citations
42 Claims
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1. A method of magnetic resonance imaging (MRI), comprising:
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magnetizing a sample comprising nuclear spins using a principle magnetic field generated external to the sample; applying to the sample a periodic pulse sequence comprising a plurality of radio frequency (rf) pulses and a plurality of recovery times between the rf pulses, wherein the pulse sequence is configured to generate, in the presence of a time-dependent magnetic field perturbation in the sample, a sequence of at least three different steady states of magnetization in the sample during each period of the pulse sequence; and processing a magnetic resonance signal acquired from the sample when under application of the periodic pulse sequence to identify characteristics of the magnetic field perturbation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method of magnetic resonance imaging (MRI), comprising:
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magnetizing a sample comprising nuclear spins using a principle magnetic field generated external to the sample; applying to the sample a periodic pulse sequence comprising a plurality of radio frequency (rf) pulses and a plurality of recovery times between the rf pulses, wherein the pulse sequence is configured to generate, in the presence of a time-dependent magnetic field perturbation in the sample, a sequence of at least two different steady states of magnetization in the sample during each period of the pulse sequence; and processing a magnetic resonance signal acquired from the sample when under application of the periodic pulse sequence to identify characteristics of an electric current in the sample. - View Dependent Claims (18, 19, 20, 21)
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22. A computer program product, embodied on a computer-readable medium, operable to cause a data processing apparatus to perform operations comprising:
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generating signals for applying to a sample a periodic pulse sequence comprising a plurality of radio frequency (rf) pulses and a plurality of recovery times between the rf pulses, wherein the pulse sequence is configured to generate a sequence of at least three different steady states of magnetization in the sample during each period of the pulse sequence; and processing a magnetic resonance signal acquired from the sample when under application of the periodic pulse sequence to identify characteristics of a magnetic field perturbation in the sample. - View Dependent Claims (23, 24, 25, 26)
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27. A magnetic resonance imaging (MRI) system comprising:
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a radio frequency (rf) system configured to apply to a sample a periodic pulse sequence comprising a plurality of radio frequency (rf) pulses and a plurality of recovery times between the rf pulses and to detect a magnetic resonance signal from the sample in response to the periodic pulse sequence, wherein the pulse sequence is configured to generate, in the presence of a time-dependent magnetic field perturbation in the sample, a sequence of at least three different steady states of magnetization in the sample during each period of the pulse sequence; and a data processing apparatus configured to process the magnetic resonance signal acquired from the sample when under application of the periodic pulse sequence to identify characteristics of a magnetic field perturbation in the sample. - View Dependent Claims (28, 29, 30, 31)
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32. A method for magnetic resonance imaging (MRI), comprising:
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magnetizing a sample using a static principal magnetic field; applying to the sample radio frequency (rf) pulses that are synchronized with time-dependent perturbations to the principal magnetic field to measure a magnetic resonance signal in a steady state to obtain a long phase integration time; and processing the measured magnetic resonance signal to uncover a weak periodic or quasi-periodic signal carried by the measured magnetic resonance signal. - View Dependent Claims (33, 34, 35)
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36. A method comprising:
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applying a periodic pulse sequence to a nervous system, the pulse sequence comprising a plurality of radio frequency (rf) pulses and a plurality of recovery times between the rf pulses, wherein the pulse sequence is configured to generate, in the presence of a time-dependent magnetic field perturbation in the nervous system, multiple different steady states of magnetization in the nervous system during each period of the pulse sequence; and processing a magnetic resonance signal acquired from the nervous system when under application of the periodic pulse sequence to obtain characteristics of neuronal activity associated with the magnetic field perturbation. - View Dependent Claims (37, 38, 39, 40, 41, 42)
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Specification