Fat suppression by combining fat saturation with fat inversion

1. A method of fat suppression during magnetic resonance imaging, the method comprising:

applying a fat suppression module to a region of interest within a subject, the fat suppression module comprising:

a fat-selective saturation pulse;

a first spoiler gradient applied following the fat-selective saturation pulse;

a fat-selective inversion pulse applied to the region of interest following a time delay, wherein the time delay is selected to allow T1 recovery in the region of interest to a predetermined level of fat magnetization at the end of the time delay;

a second spoiler gradient applied following the fat-selective inversion pulse;

following application of the fat suppression module, performing a sequence readout to acquire one or more lines of k-space data covering the region of interest.

2. The method of claim 1 , wherein the fat-selective inversion pulse is an adiabatic pulse.

3. The method of claim 1 , wherein the fat-selective saturation pulse is adiabatic.

4. The method of claim 1 , wherein the sequence readout comprises a turbo-spin echo readout train and the time delay is selected such that fat magnetization in the region of interest is substantially zero at the beginning of the turbo-spin echo readout train.

5. The method of claim 1 , wherein the time delay is selected such that fat magnetization is a predetermined value when the sequence readout acquires a contrast-relevant portion of k-space.

6. The method of claim 5 , wherein the predetermined value is zero.

7. The method of claim 1 , wherein the amplitude and sign of the first spoiler gradient is determined by a random or pseudo-random scheme.

8. The method of claim 7 , wherein the amplitude and sign of the second spoiler gradient is determined by the random or pseudo-random scheme.

9. A method of fat suppression during magnetic resonance imaging, the method comprising:

applying a fat suppression module to a region of interest within a subject, the fat suppression module comprising:

a series of fat-selective saturation pulses, wherein a first spoiler gradient is applied to the region of interest following each fat-selective saturation pulse;

a time delay starting and the end of the series of fat-selective saturation pulses, wherein the time delay is selected to allow T1 recovery in the region of interest to a predetermined level of fat magnetization at the end of the time delay;

a fat-selective inversion pulse applied to the region of interest following the time delay; and

a second spoiler gradient applied following the fat-selective inversion pulse;

following application of the fat suppression module, acquiring one or more lines of k-space data covering the region of interest.

10. The method of claim 9 , wherein the series of fat-selective saturation pulses is applied at different frequencies within 100 Hz of a fat frequency.

11. The method of claim 9 , wherein the series of fat-selective saturation pulses each have a different flip angle between 90° and 180°.

12. The method of claim 9 , wherein the series of fat-selective saturation pulses are each rotated around a different axis.

13. The method of claim 9 , wherein the sequence readout comprises a turbo-spin echo readout train and the time delay is selected such that fat magnetization in the region of interest is substantially zero at the beginning of the turbo-spin echo readout train.

14. The method of claim 11 , wherein the time delay is selected such that fat magnetization is a predetermined value when the sequence readout acquires a contrast-relevant portion of k-space.

15. The method of claim 14 , wherein the predetermined value is zero.

16. A system for fat suppression during magnetic resonance imaging, the system comprising:

an imaging device comprising a plurality of coils;

one or more processors; and

a non-transitory, computer-readable storage medium in operable communication with the processor, wherein the computer-readable storage medium contains one or more programming instructions that, when executed, cause the processors to:

apply a fat suppression module to a region of interest within a subject using the coils, the fat suppression module comprising:

one or more fat-selective saturation pulses;

a first spoiler gradient applied following each fat-selective saturation pulse;

a fat-selective inversion pulse applied to the region of interest following a time delay, wherein the time delay is selected to allow T1 recovery in the region of interest to a predetermined level of fat magnetization at the end of the time delay;

a second spoiler gradient applied following the fat-selective inversion pulse;

following application of the fat suppression module, use the plurality of coils to acquire one or more lines of k-space data covering the region of interest.

17. The system of claim 16 , wherein the fat-selective inversion pulse is an adiabatic pulse.

18. The system of claim 16 , wherein the fat-selective saturation pulse is adiabatic.

19. The system of claim 16 , wherein the one or more lines of k-space data are acquired using a turbo-spin echo readout train and the time delay is selected such that fat magnetization in the region of interest is substantially zero at the beginning of the turbo-spin echo readout train.

20. The system of claim 16 , wherein the time delay is selected such that fat magnetization is a predetermined value when the sequence readout acquires a contrast-relevant portion of k-space.