Nuclear magnetic resonance (NMR) fingerprinting

Patent metadata

Field	Value
Publication number	US-10627468-B2
Application number	US-201213623104-A
Country	US
Kind code	B2
Filing date	Sep 19, 2012
Priority date	Mar 18, 2011
Publication date	Apr 21, 2020
Grant date	Apr 21, 2020

Abstract

Apparatus, methods, and other embodiments associated with NMR fingerprinting are described. One example NMR apparatus includes an NMR logic configured to repetitively and variably sample a (k, t, E) space associated with an object to acquire a set of NMR signals. Members of the set of NMR signals are associated with different points in the (k, t, E) space. Sampling is performed with t and/or E varying in a non-constant way. The varying parameters may include flip angle, echo time, RF amplitude, and other parameters. The NMR apparatus may also include a signal logic configured to produce an NMR signal evolution from the NMR signals, and a characterization logic configured to characterize a resonant species in the object as a result of comparing acquired signals to reference signals.

First claim

What is claimed is:

1. A method, comprising:
exposing a material to nuclear magnetic resonance (NMR) fingerprinting excitation using an NMR system by:
controlling the NMR apparatus to apply radio frequency (RF) energy to the material in a series of variable sequence blocks, where a sequence block includes one or more excitation phases, one or more readout phases, and one or more waiting phases,
where the material contains a plurality of resonant species,
where the RF energy applied during a sequence block is configured to cause the plurality of resonant species in the material to simultaneously produce NMR signals, wherein each resonant species in the material simultaneously produces a respective NMR signal to produce the NMR signals, and
where at least one member of the series of variable sequence blocks differs from at least one other member of the series of variable sequence blocks in at least N sequence block parameters, N being an integer greater than one;

acquiring NMR signals from the material elicited by the NMR fingerprinting excitation; and
indicating a presence of the material and quantifying a property of the material exposed to the NMR fingerprinting excitation by comparing first information associated with the NMR signals acquired from the material in response to the NMR fingerprinting excitation to reference information associated with the NMR fingerprinting excitation.

2. The method of claim 1 , where quantifying the property includes quantifying one or more of, T1 associated with the material, T2 associated with the material, a diffusion coefficient associated with the material, a spin density associated with the material, a proton density associated with the material, a magnetic field to which the material was exposed, or a gradient field to which material was exposed, T1 being spin-lattice relaxation, and T2 being spin-spin relaxation.

3. The method of claim 2 , where quantifying the property includes one or more of, identifying a portion of the reference information related to the first information, identifying a degree to which a portion of the reference information is related to the first information, and identifying the likelihood that a portion of the reference information is related to the first information.

4. The method of claim 1 , where the first information includes one or more of, the NMR signals acquired from the material in response to the NMR fingerprinting excitation, a signal evolution produced from the NMR signals acquired from the material in response to the NMR fingerprinting excitation, and information derived from the signal evolution produced from the NMR signals acquired from the material in response to the NMR fingerprinting excitation.

5. The method of claim 4 , where the information derived from the signal evolution includes one or more of, information derived by transforming the signal evolution, information derived by combining the signal evolution with one or more other signal evolutions, and information derived by decomposing the signal evolution.

6. The method of claim 1 , where the reference information includes one or more of, a previously acquired NMR signal, a modeled NMR signal, a previously acquired signal evolution, a modeled signal evolution, information derived from a reference signal evolution, and non-signal evolution information.

7. The method of claim 6 , where the information derived from the reference signal evolution includes one or more of, information derived by transforming the reference signal evolution, information derived by combining the reference signal evolution with one or more other reference signal evolutions, and information derived by decomposing the reference signal evolution.

8. The method of claim 1 , where comparing the first information to the reference information includes one or more of, pattern matching, selecting, minimizing, and optimizing.

9. The method of claim 8 , where pattern matching includes one or more of, orthogonal matching pursuit, categorical sequence labeling, regression, clustering, classification, real valued sequence labeling, parsing, Bayesian methods, Markov methods, ensemble learning methods, and template matching.

10. The method of claim 8 , where optimization includes one or more of, least squares optimization, regularized least squares optimization, basis pursuit optimization, and matching pursuit optimization.

11. The method of claim 1 , where the sequence block parameters comprise echo time, flip angle, phase encoding, diffusion encoding, flow encoding, RF pulse amplitude, RF pulse phase, number of RF pulses, type of gradient applied between an excitation portion of a sequence block and a readout portion of a sequence block, number of gradients applied between an excitation portion of a sequence block and a readout portion of a sequence block, type of gradient applied between a readout portion of a sequence block and an excitation portion of a sequence block, number of gradients applied between a readout portion of a sequence block and an excitation portion of a sequence block, type of gradient applied during a readout portion of a sequence block, number of gradients applied during a readout portion of a sequence block, amount of RF spoiling, and amount of gradient spoiling.

12. The method of claim 1 , comprising:
controlling the NMR apparatus to vary one or more of, the amount of time between sequence blocks in the series of variable sequence blocks, the relative amplitude of RF pulses in sequence blocks in the series of variable sequence blocks, and the relative phase of RF pulses in sequence blocks in the series of variable sequence blocks.

13. The method of claim 1 , where N is greater than two and where at least one percent of the members of the series of variable sequence blocks are unique.

14. The method of claim 1 , where the reference information includes signal evolutions outside the set of signal evolutions characterized by:
SE= A−Be t/C
where:
SE is a signal evolution,
A is a constant,
B is a constant,
t is time, and
C is a single relaxation parameter.

15. A method, comprising:
controlling an NMR apparatus to expose the material to NMR fingerprinting excitation by:
controlling the NMR apparatus to apply radio frequency (RF) energy to the material in a series of variable sequence blocks, where a sequence block includes one or more excitation phases, one or more readout phases, and one or more waiting phases,
where the material contains one or more resonant species,
where the RF energy applied during a sequence block is configured to cause the one or more resonant species in the material to simultaneously produce NMR signals, wherein each resonant species in the material simultaneously produces a respective NMR signal to produce the NMR signals,
where at least one member of the series of variable sequence blocks differs from at least one other member of the series of variable sequence blocks in at least N sequence block parameters, N being an integer greater than one,

characterizing a property of a material exposed to nuclear magnetic resonance (NMR) fingerprinting excitation by comparing first information associated with NMR signals acquired from the material in response to the NMR fingerprinting excitation to reference information associated with NMR fingerprinting excitation, and
where the reference information includes signal evolutions selected from a set of signals described by:

SE
=

∏

i

Assignees

• Univ Case Western Reserve

Inventors

• Griswold Mark
• Seiberlich Nicole
• Gulani Vikas
• Ma Dan

Classifications

• G01R33/56341

  Diffusion imaging · CPC title

• G01R33/56 Primary

  Image enhancement or correction, e.g. subtraction or averaging techniques {, e.g. improvement of signal-to-noise ratio and resolution} · CPC title

• G01R33/4828

  Resolving the MR signals of different chemical species, e.g. water-fat imaging · CPC title

• G01R33/50

  based on the determination of relaxation times {, e.g. T1 measurement by IR sequences; T2 measurement by multiple-echo sequences} · CPC title