Systems and methods for multislice magetic resonance fingerprinting

Patent metadata

Field	Value
Publication number	US-10488481-B2
Application number	US-201815900910-A
Country	US
Kind code	B2
Filing date	Feb 21, 2018
Priority date	Feb 22, 2017
Publication date	Nov 26, 2019
Grant date	Nov 26, 2019

Abstract

Systems and methods for multislice magnetic resonance fingerprinting (“MRF”) are provided. Data are acquired from multiple different slices, either simultaneously or sequentially, using a schedule of acquisition parameters that are optimized or otherwise selected for each different slice. Dictionary matching techniques are then used to estimate quantitative parameters from the acquired data. The methods can provide both in-plane and through-plane acceleration without the use of multi-channel radio frequency coils.

First claim

The invention claimed is:

1. A method for estimating quantitative parameters of a subject using a magnetic resonance imaging (MRI) system, the steps of the method comprising:
(a) selecting for each of a plurality of different slices, a schedule of acquisition parameters wherein each schedule of acquisition parameters is selected to direct an MRI system to generate a plurality of different signal evolutions that maximize discrimination between different quantitative parameters in a minimized number of repetition time (TR) periods;
(b) acquiring data with the MRI system by directing the MRI system to perform a plurality of pulse sequences using the selected schedules of acquisition parameters, wherein each of the plurality of pulse sequences implements radio frequency (RF) excitation of the plurality of different slices in each TR period, and wherein the acquired data represent the plurality of different signal evolutions that maximize discrimination between different quantitative parameters; and
(c) estimating quantitative parameters of the subject by comparing the acquired data with a dictionary database comprising a plurality of different signal templates.

2. The method as recited in claim 1 , wherein each of the plurality of pulse sequences implements RF excitation of the plurality of different slices in each TR period using a simultaneous RF excitation in which each of the plurality of slices is excited simultaneously.

3. The method as recited in claim 2 , wherein the RF excitation includes applying a multiband RF pulse comprising a plurality of component RF pulses, and wherein each of the plurality of component RF pulses has a frequency offset associated with one of the plurality of different slices.

4. The method as recited in claim 3 , wherein each schedule of acquisition parameters includes a schedule of flip angles, TRs, and frequency offsets.

5. The method as recited in claim 1 , wherein the data are acquired in step (b) using a multi-channel RF coil.

6. The method as recited in claim 5 , wherein each of the plurality of pulse sequences implements an undersampling of k-space in a plane of k-space that is orthogonal to a slice encoding direction.

7. The method as recited in claim 1 , wherein the data are acquired in step (b) using a single channel RF coil.

8. The method as recited in claim 1 , wherein each of the plurality of pulse sequences implements RF excitation of the plurality of different slices in each TR period using RF excitation pulses that are applied sequentially in time.

9. The method as recited in claim 8 , wherein each of the RF excitation pulses applied in a given TR period has a different frequency offset associated with one of the plurality of different slices.

10. The method as recited in claim 9 , wherein each schedule of acquisition parameters includes a schedule of flip angles, TRs, and frequency offsets.

11. The method as recited in claim 10 , wherein each schedule of acquisition parameters also include a schedule of echo times.

12. The method as recited in claim 1 , wherein selecting the schedules of acquisition parameters includes estimating the acquisition parameters by minimizing an objective function that simulates the acquisition parameters and computes a matrix that is based on estimated values of the acquisition parameters and the quantitative parameters to be estimated.

13. A magnetic resonance imaging (MRI) system, comprising:
a magnet system configured to generate a polarizing magnetic field;
a magnetic gradient system including a plurality of magnetic gradient coils configured to apply at least one magnetic gradient field to the polarizing magnetic field;
a radio frequency (RF) system configured to apply an RF field to a subject arranged in the polarizing magnetic field and to receive magnetic resonance signals from the subject using an RF coil;
a computer system programmed to:
select for each of a plurality of different slices, a schedule of acquisition parameters wherein each schedule of acquisition parameters is selected to direct an MRI system to generate a plurality of different signal evolutions that maximize discrimination between different quantitative parameters in a minimized number of repetition time (TR) periods;
direct the gradient system and the RF system to acquire data by performing a plurality of pulse sequences using the selected schedules of acquisition parameters, wherein each of the plurality of pulse sequences implements RF excitation of the plurality of different slices in each TR period, and wherein the acquired data represent the plurality of different signal evolutions that maximize discrimination between different quantitative parameters; and
estimate quantitative parameters of the subject by comparing the acquired data with a dictionary database comprising a plurality of different signal templates.

14. The MRI system as recited in claim 13 , wherein each of the plurality of pulse sequences implements RF excitation of the plurality of different slices in each TR period using a simultaneous RF excitation in which each of the plurality of slices is excited simultaneously.

15. The MRI system as recited in claim 14 , wherein the RF excitation includes directing the RF system to apply a multiband RF pulse comprising a plurality of component RF pulses, and wherein each of the plurality of component RF pulses has a frequency offset associated with one of the plurality of different slices.

16. The MRI system as recited in claim 15 , wherein each schedule of acquisition parameters includes a schedule of flip angles, TRs, and frequency offsets.

17. The MRI system as recited in claim 13 , wherein the RF coil is a multi-channel RF coil.

18. The MRI system as recited in claim 17 , wherein each of the plurality of pulse sequences implements an undersampling of k-space in a plane of k-space that is orthogonal to a slice encoding direction.

19. The MRI system as recited in claim 13 , wherein the RF coil is a single channel RF coil.

20. The MRI system as recited in claim 13 , wherein each of the plurality of pulse sequences implements RF excitation of the plurality of different slices in each TR period using RF excitation pulses that are applied sequentially in time by the RF system.

21. The MRI system as recited in claim 20 , wherein each of the RF excitation pulses applied in a given TR period has a different frequency offset associated with one of the plurality of different slices.

22. The MRI system as recited in claim 21 , wherein each schedule of acquisition parameters includes a schedule of flip angles, TRs, and frequency offsets.

23. The MRI system as recited in claim 22 , wherein each schedule of acquisition parameters also include a schedule of echo times.

Assignees

• Massachusetts Gen Hospital

Inventors

• Cohen Ouri

Classifications

• G01R33/543 Primary

  Control of the operation of the MR system, e.g. setting of acquisition parameters prior to or during MR data acquisition, dynamic shimming, use of one or more scout images for scan plane prescription (G01R33/546 takes precedence) · CPC title

• G01R33/5615

  Echo train techniques involving acquiring plural, differently encoded, echo signals after one RF excitation, e.g. using gradient refocusing in echo planar imaging [EPI], RF refocusing in rapid acquisition with relaxation enhancement [RARE] or using both RF and gradient refocusing in gradient and spin echo imaging [GRASE] · CPC title

• G01R33/5611

  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 title

• G01R33/4835 Primary

  of multiple slices · CPC title