Magnetic Resonance Fingerprinting (MRF) With Simultaneous Multivolume Acquisition

• US 20150346300A1
• Filed: 05/14/2015
• Published: 12/03/2015
• Est. Priority Date: 05/28/2014
• Status: Active Grant

• Current Assignee: Case Western Reserve University, The General Hospital Corporation (Mass General Brigham, Inc.)
• Original Assignee: Case Western Reserve University
• Inventors: Setsompop, Kawin, Griswold, Mark, Wald, Lawrence, Ma, Dan, Jiang, Yun, Ye, Huihui
• Granted Patent: US 9,897,675 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01R 33/4824 using a non-Cartesian trajectory
• CPC Class Codes: G01R 33/4828 Resolving the MR signals of different chemical species, e.g. water-fat imaging
• CPC Class Codes: G01R 33/50 based on the determination of relaxation times , e.g. T1 measurement by IR sequences; T2 measurement by multiple-echo sequences
• CPC Class Codes: G01R 33/5611 Parallel magnetic resonance imaging, e.g. sensitivity encoding [SENSE], simultaneous acquisition of spatial harmonics [SMASH], unaliasing by Fourier encoding of the overlaps using the temporal dimension [UNFOLD], k-t-broad-use linear acquisition speed-up technique [k-t-BLAST], k-t-SENSE structural details of arrays of sub-coils G01R33/3415
• CPC Class Codes: G01R 33/5613 Generating steady state signals, e.g. low flip angle sequences [FLASH]

Abstract

Magnetic resonance fingerprinting (MRF) with simultaneous multivolume acquisition (SMVA) is described. One example nuclear magnetic resonance (NMR) apparatus includes an NMR logic that repetitively and variably samples (k, t, E) spaces associated with different volumes (e.g., slices) in an object to simultaneously acquire sets of NMR signals that are associated with different points in the (k, t, E) spaces. Sampling is performed with t and/or E varying in a non-constant way. The NMR apparatus may also include a signal logic that produces an NMR signal evolution from the NMR signals and compares the NMR signal evolution to reference signal evolutions. Since different volumes are excited differently, resulting signal evolutions can be acquired simultaneously from the different volumes and NMR parameters may be simultaneously determined for the multiple volumes, which reduces acquisition time and parameter map creation time.

Claims

1. A method for creating a parameter map or an image from data acquired by controlling a magnetic resonance imaging (MRI) apparatus to perform magnetic resonance fingerprinting with simultaneous multivolume acquisition (MRF-SMVA), comprising:

controlling the MRI apparatus to create a first nuclear magnetic resonance (NMR) excitation in a first volume in a sample according to a first set of magnetic resonance fingerprinting (MRF) parameters;

controlling the MRI apparatus to create a second, different NMR excitation in a second volume in the sample according to a second set of MRF parameters;

controlling the MRI apparatus to acquire first NMR signals produced by the first volume in response to the first NMR excitation;

producing a first signal evolution from the first NMR signals, the first signal evolution having complex values with an arbitrary phase relationship;

controlling the MRI apparatus to acquire second NMR signals produced by the second volume in response to the second NMR excitation;

producing a second signal evolution from the second NMR signals, the second signal evolution having complex values with an arbitrary phase relationship;

simultaneously determining two or more first quantitative magnetic resonance (MR) parameters for a portion of the first volume based on a comparison of the first signal evolution to one or more known signal evolutions;

simultaneously determining two or more second quantitative MR parameters for a portion of the second volume based on a comparison of the second signal evolution to one or more known signal evolutions; and

producing the parameter map or the image based, at least in part, on the two or more first quantitative MR parameters or based, at least in part, on the two or more second quantitative parameters,

where the first NMR excitation and the second NMR excitation are active simultaneously, and

where the first NMR signals and the second NMR signals are acquired simultaneously.

2. The method of claim 1, comprising acquiring the first NMR signals and the second NMR signals simultaneously as discrete signals.

3. The method of claim 2, comprising independently comparing the first signal evolution and the second signal evolution to the one or more known signal evolutions.

4. The method of claim 1, comprising acquiring the first NMR signals and the second NMR signals simultaneously as a mixed signal, where the first signal evolution and the second signal evolution are combined as a mixed signal evolution.

5. The method of claim 4, comprising comparing the mixed signal evolution to the one or more known signal evolutions.

6. The method of claim 4, comprising separating the mixed signal into the first signal evolution and the second signal evolution before determining the two or more quantitative MR parameters for the portion of the first volume and before determining the two or more quantitative MR parameters for the portion of the second volume.

7. The method of claim 6, comprising individually comparing the first signal evolution and the second signal evolution to the one or more known signal evolutions.

8. The method of claim 4, comprising separating the mixed signal by performing a generalized auto-calibrating partially parallel acquisition (GRAPPA) operation on the mixed signal, by performing a slice generalized auto-calibrating partially parallel acquisition (slice-GRAPPA) operation on the mixed signal, or by performing a generalized auto-calibrating parallel acquisition (GRAPPA) operator (GROG) slice operation on the mixed signal.

9. The method of claim 1, comprising controlling the MRI apparatus to produce the first NMR excitation and the second NMR excitation according to a Fast-Imaging with Steady-state Precession FISP-MRF pulse sequence or an inversion recovery FISP (IR TrueFISP) pulse sequence.

10. The method of claim 1, comprising controlling the MRI apparatus to produce the first NMR excitation and the second NMR excitation according to a balanced steady state free precession (bSSFP) MRF pulse sequence.

11. The method of claim 1, where the first set of MRF parameters and the second set of MRF parameters are selected to cause the first signal evolution and the second signal evolution to be correlated less than a threshold amount.

12. The method of claim 1, where the two or more quantitative MR parameters include T1, T2, M0, and proton density, T1 being spin-lattice relaxation, T2 being spin-spin relaxation, and M0 being initial magnetization.

13. The method of claim 1, where the first set of MRF parameters and the second set of MRF parameters are selected to produce:

a different flip angle train in the first NMR excitation and the second NMR excitation,

different phases in a flip angle train in the first NMR excitation and the second NMR excitation, or

different magnitudes in a flip angle train in the first NMR excitation and the second NMR excitation.

14. The method of claim 1,

where the first volume is a slice,

where the second volume is a slice, and

where the first set of MRF parameters and the second set of MRF parameters are selected to cause different gradients to be applied to the first slice and to the second slice.

15. The method of claim 14, where causing the different gradients to be applied to the first slice and to the second slice includes causing different slice select gradients to be applied to the first slice and to the second slice.

16. The method of claim 15, comprising controlling the different slice select gradients to differ before, during, or after acquiring the first NMR signals and the second NMR signals.

17. The method of claim 16, where the different slice select gradients are configured to cause a phase shift between the first slice and the second slice.

18. The method of claim 17, where the phase shift is configured to:

spatially shift the first slice and the second slice relative to each other in an image field-of-view,

produce spatial blurring in at least one of the first slice or the second slice, or

produce a spatial distortion in at least one of the first slice or the second slice.

19. The method of claim 18, comprising controlling the different slice select gradients to match at least one readout gradient applied during acquisition of the first NMR signals or acquisition of the second NMR signals, where the at least one readout gradient is applied in a direction different than the different slice select gradients.

20. The method of claim 19,

where the at least one readout gradient comprises a first readout gradient applied in a first direction orthogonal to the slice-encoding direction and a second readout gradient applied in a second direction orthogonal to the slice-encoding direction, and

where the magnetic gradient applied along the slice-encoding direction matches the at least one readout gradient by weighting a combination of the first readout gradient and the second readout gradient.

21. The method of claim 20, where the combination of the first readout gradient and the second readout gradient is an addition of the first readout gradient and the second readout gradient.

22. The method of claim 1, comprising:

controlling the MRI apparatus to create a first single volume NMR excitation in the first volume according to the first set of NMR parameters;

controlling the MRI apparatus to acquire a first single volume set of NMR signals produced by the first volume in response to the first single volume NMR excitation;

producing a first single volume signal evolution from the first single volume set of NMR signals;

simultaneously determining two or more first single volume quantitative MR parameters for a portion of the first volume based on a comparison of the first single volume evolution to one or more known signal evolutions; and

producing the parameter map or the image based, at least in part, on the two or more first single volume quantitative MR parameters,

where the first single volume NMR signals are acquired independently of the first NMR signals and the second NMR signals, and

where the first single volume NMR excitation is active at a time other than when the first NMR excitation and the second NMR excitation are active.

23. The method of claim 22, comprising:

controlling the MRI apparatus to create a second single volume NMR excitation in the second volume according to the second set of NMR parameters;

controlling the MRI apparatus to acquire a second single volume set of NMR signals produced by the second volume in response to the second single volume NMR excitation;

producing a second single volume signal evolution from the second single volume set of NMR signals;

simultaneously determining two or more second single volume quantitative MR parameters for a portion of the second volume based on a comparison of the second single volume evolution to one or more known signal evolutions; and

producing the parameter map or the image based, at least in part, on the two or more second single volume quantitative MR parameters,

where the second single volume NMR signals are acquired independently of the first NMR signals and the second NMR signals, and

where the second single volume NMR excitation is active at a time other than when the first single volume NMR excitation, the first NMR excitation, and the second NMR excitation are active.

24. The method of claim 1, comprising acquiring the first NMR signals and the second NMR signals using different sampling patterns.

25. The method of claim 1, comprising acquiring the first NMR signals and the second NMR signals using a slice direction sensitivity encoding (SENSE) approach.

26. The method of claim 1, where creating the first NMR excitation comprises applying gradients and radio frequency (RF) energy to the first volume in a first series of variable sequence blocks, where a member of the first series of variable sequence blocks includes one or more excitation phases, one or more readout phases, and one or more waiting phases,

where the RF energy applied during a member of the first series of variable sequence blocks causes the one or more resonant species in the first volume to simultaneously produce individual NMR signals, and

where at least one member of the first series of variable sequence blocks differs from at least one other member of the first series of variable sequence blocks in at least N sequence block parameters, N being an integer greater than one,

and

where creating the second NMR excitation comprises applying gradients and RF energy to the second volume in a second series of variable sequence blocks, where a member of the second series of variable sequence blocks includes one or more excitation phases, one or more readout phases, and one or more waiting phases,

where the RF energy applied during a member of the second series of variable sequence blocks causes the one or more resonant species in the second volume to simultaneously produce individual NMR signals, and

where at least one member of the second series of variable sequence blocks differs from at least one other member of the second series of variable sequence blocks in at least M sequence block parameters, M being an integer greater than one,

and

where the first series of variable sequence blocks differs from the second series of variable sequence blocks.

27. The method of claim 26, where the sequence block parameters include 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, an amount by which a gradient is unbalanced when applied between an excitation portion of a sequence block and a readout portion of a sequence bock, a type of gradient applied between a readout portion of a sequence block and an excitation portion of a sequence block, a number of gradients applied between a readout portion of a sequence block and an excitation portion of a sequence block, an amount by which a gradient is unbalanced when applied between a readout portion of a sequence block and an excitation portion of a sequence bock, a type of gradient applied during a readout portion of a sequence block, a number of gradients applied during a readout portion of a sequence block, an amount of RF spoiling, or an amount of gradient spoiling.

28. The method of claim 27, comprising:

controlling the MRI apparatus to vary an amount of time between sequence blocks in a series of variable sequence blocks, the relative amplitude of RF pulses in sequence blocks in a series of variable sequence blocks, or the relative phase of RF pulses in sequence blocks in a series of variable sequence blocks.

29. The method of claim 1, where the one or more known signal evolutions include signal evolutions outside the set of signal evolutions characterized by:

SE=A−

Be<sup>−

t/C</sup>

where;

SE is a signal evolution,

A is a constant,

B is a constant,

t is time, and

C is a single relaxation parameter.

30. The method of claim 1, where the one or more known signal evolutions include a signal selected from a set of signals described by:

31. The method of claim 1, where the one or more known signal evolutions include a signal selected from a set of signals described by:

S_i=R_iE_i(S_i-1)

where;

S₀ is the default or equilibrium magnetization.

S_i is a vector that represents the different components of the magnetization Mx, My, Mz during acquisition block i,

R_i is the combination of rotational effects that occur during acquisition block i, and

E_i is the combination of effects that alter the amount of magnetization in the different states for acquisition block i.

32. The method of claim 1, where the one or more known signal evolutions include a signal selected from a set of signals described by:

33. The method of claim 1, where the one or more known signal evolutions include a signal selected from a set of signals described by:

34. The method of claim 1, where the one or more known signal evolutions include a signal selected from a set of signals described by:

35. A method for creating a parameter map or an image from data acquired by controlling a magnetic resonance imaging (MRI) apparatus to perform magnetic resonance fingerprinting with simultaneous multivolume acquisition (MRF-SMVA), comprising:

controlling the MRI apparatus to create different nuclear magnetic resonance (NMR) excitations in a plurality of volumes in a sample using a plurality of different magnetic resonance fingerprinting (MRF) pulse sequences described by a plurality of MRF parameters;

controlling the MRI apparatus to acquire NMR signals produced by members of the plurality of volumes in response to the different NMR excitations;

producing a plurality of signal evolutions from the NMR signals;

simultaneously determining two or more quantitative magnetic resonance (MR) parameters for a volume in the plurality of volumes based on a comparison of members of the plurality of signal evolutions to one or more known signal evolutions; and

producing the parameter map or the image based, at least in part, on the two or more quantitative MR parameters,

where at least two members of the plurality of volumes have NMR excitations active simultaneously, and

where the NMR signals are acquired simultaneously from the at least two members of the plurality of volumes.

36. The method of claim 35, where at least three members of the plurality of volumes have NMR excitations active simultaneously, and where the NMR signals are acquired simultaneously from the at least three members of the plurality of volumes.

37. The method of claim 35, where at least four members of the plurality of volumes have NMR excitations active simultaneously, and where the NMR signals are acquired simultaneously from the at least four members of the plurality of volumes.

38. The method of claim 35, where at least eight members of the plurality of volumes have NMR excitations active simultaneously, and where the NMR signals are acquired simultaneously from at the least eight members of the plurality of volumes.

39. An apparatus, comprising:

an excitation logic that causes a magnetic resonance fingerprinting (MRF) apparatus to create different MRF excitations in a plurality of different slices in an object, where the different MRF excitations are active at the same time;

a nuclear magnetic resonance (NMR) logic that receives a first set of data from the MRF apparatus in response to the MRF apparatus repetitively and variably sampling a (k, t, E) space associated with the object,

where the MRF apparatus applies radio frequency (RF) energy and gradients to the object according to an MRF pulse sequence to cause the object to produce the first set of NMR signals,

where members of the first set of data are associated with different points in the (k, t, E) space, where t is time and E includes at least T1 and T2, T1 being spin-lattice relaxation and T2 being spin-spin relaxation, and where one or more of, t and E, vary non-linearly, and

where the first set of data includes signals from the plurality of slices,

a signal logic that produces one or more NMR signal evolutions from the first set of data;

a matching logic that selects, from a collection of stored signal evolutions, one or more selected stored signal evolutions that match one or more members of the one or more NMR signal evolutions to within a desired tolerance, and

a parameter map logic that simultaneously produces parameter maps or images for members of the plurality of slices based, at least in part, on the one or more selected stored signal evolutions.

40. The apparatus of claim 39, comprising:

a characterization logic that identifies the object as having a property based, at least in part, on the plurality of parameter maps, where the property describes whether the object is a diseased tissue or a healthy tissue.

41. The apparatus of claim 39, comprising a separation logic that separates the one or more NMR signal evolutions from the first set of data by performing a generalized auto-calibrating partially parallel acquisition (GRAPPA) operation on the first set of data, by performing a slice generalized auto-calibrating partially parallel acquisition (slice-GRAPPA) operation on the first set of data, or by performing a generalized auto-calibrating parallel acquisition (GRAPPA) operator (GROG) slice operation on the first set of data.

42. The apparatus of claim 39, where the MRF pulse sequences produces flip angle trains having different numbers, phases, or magnitudes in two or more members of the plurality of different slices.

43. The apparatus of claim 39, where the MRF pulse sequence causes different gradients to be applied to two or more members of the plurality of different slices before, during, or after receiving the first set of data, where the different gradients are configured to:

cause a phase shift between the two or more members of the plurality of slices,

spatially shift two or more members of the plurality of slices relative to each other in an image field-of-view,

produce spatial blurring in at least one member of the plurality of slices, or

produce a spatial distortion in at least one member of the plurality of slices.

44. The apparatus of claim 39, where the MRF pulse sequence is a Fast-Imaging with Steady-state Precession FISP-MRF pulse sequence, an inversion recovery FISP (IR TrueFISP) pulse sequence, or a balanced steady state free precession (bSSFP) MRF pulse sequence.

45. The apparatus of claim 40, where the E in the (k, t, E) space includes two or more parameters selected from the group comprising:

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, an amount by which a gradient is unbalanced when applied between an excitation portion of a sequence block and a readout portion of a sequence bock, a type of gradient applied between a readout portion of a sequence block and an excitation portion of a sequence block, a number of gradients applied between a readout portion of a sequence block and an excitation portion of a sequence block, an amount by which a gradient is unbalanced when applied between a readout portion of a sequence block and an excitation portion of a sequence bock, a type of gradient applied during a readout portion of a sequence block, a number of gradients applied during a readout portion of a sequence block, an amount of RF spoiling, an amount of gradient spoiling, an amount of time between sequence blocks in a series of variable sequence blocks, the relative amplitude of RF pulses in sequence blocks in a series of variable sequence blocks, and the relative phase of RF pulses in sequence blocks in a series of variable sequence blocks.

46. The apparatus of claim 39, where the collection of stored signal evolutions includes a signal selected from the MRF dictionary signal equations.

47. The apparatus of claim 39, where

the excitation logic causes the MRF apparatus to create a standalone MRF excitation in a member of the plurality of different slices, where the standalone MRF excitation is not active at the same time as the different MRF excitations in the plurality of different slices;

the NMR logic receives a second set of data from the MRF apparatus in response to the MRF apparatus repetitively and variably sampling a (k, t, E) space associated with standalone MRF excitation to acquire the second set of NMR signals,

where the MRF apparatus applies RF energy and gradients to the object according to an MRF pulse sequence to cause the object to produce the second set of NMR signals,

where members of the second set of data are associated with different points in the (k, t, E) space, where t is time and E includes at least T1 and T2, T1 being spin-lattice relaxation and T2 being spin-spin relaxation, and where one or more of, t and E, vary non-linearly, and

where the second set of data includes signals from the member of the plurality of different slices that is experiencing the standalone MRF excitation,

the signal logic produces a standalone NMR signal evolution from the second set of data;

the matching logic selects, from a collection of stored signal evolutions, a selected stored signal evolution that matches the standalone NMR signal evolution to within a desired tolerance, and

the parameter map logic simultaneously produces the parameter maps or images for at least one member of the plurality of slices based, at least in part, on the selected stored signal evolution.

48. An apparatus, comprising:

a collection logic that collects a received signal evolution from multiple simultaneously excited slices of tissue experiencing nuclear magnetic resonance (NMR) in response to a magnetic resonance fingerprinting (MRF) excitation applied to the tissue by a magnetic resonance imaging (MRI) apparatus, where members of the multiple simultaneously excited slices of tissue are experiencing different NMR;

a data store that stores a dictionary of MRF signal evolutions, where members of the dictionary are combinations of information associated with two or more resonant species, and where information concerning the composition of the tissue with respect to the two or more resonant species is retrievable using a matched signal evolution;

a selection logic that selects a matching member of the dictionary that is most closely related to the received signal evolution and establishes the matching member as the matched signal evolution, and

a characterization logic that identifies a category for the tissue based, at least in part, on the composition of the tissue as identified using the matched signal evolution.