Noise suppression methods and apparatus

1. A method of estimating noise detected in an environment of a magnetic resonance imaging system, the method comprising:

acquiring a plurality of magnetic resonance signals by repeatedly applying a first pulse sequence using a first spatial encoding; and

estimating noise based, at least in part, on a comparison of the plurality of magnetic resonance signals.

2. The method of claim 1 , wherein acquiring the plurality of magnetic resonance signals comprises:

acquiring at least one first magnetic resonance signal by applying the first pulse sequence using the first spatial encoding; and

acquiring at least one second magnetic resonance signal by applying the first pulse sequence using the first spatial encoding, and

wherein estimating the noise comprises estimating noise based, at least in part, on a comparison of the at least one first magnetic resonance signal and the at least one second magnetic resonance signal.

3. The method of claim 2 , further comprising:

estimating a transform based, at least in part, on multiple calibration measurements obtained from at least one primary coil and at least one auxiliary sensor, respectively;

estimating noise present in a magnetic resonance signal received by the at least one primary coil based at least in part on the transform; and

suppressing noise in the magnetic resonance signal using the noise estimate.

4. The method of claim 2 , comprising aligning the at least one first magnetic resonance signal and the at least one second magnetic resonance signal using a phase shift.

5. The method of claim 4 , wherein the comparison comprises computing a difference between the aligned at least one first magnetic resonance signal and the at least one second magnetic resonance signal.

6. The method of claim 5 , wherein estimating the noise is based on subtracting the at least one first magnetic resonance signal and the at least one second magnetic resonance signal.

7. The method of claim 5 , wherein estimating the noise is based on adding the at least one first magnetic resonance signal and the at least one second magnetic resonance signal.

8. The method of claim 2 , wherein the at least one first magnetic resonance signal comprises a first plurality of averaged magnetic resonance signals acquired using the first spatial encoding.

9. The method of claim 2 , wherein the at least one first magnetic resonance signal and the at least one second magnetic resonance signal are both used to produce at least one magnetic resonance image.

10. The method of claim 1 , wherein the noise estimate is used to dynamically suppress noise in magnetic resonance signals obtained during operation of the magnetic resonance imaging system.

11. The method of claim 1 , wherein the first pulse sequence is a balanced steady state free precession (bSSFP) pulse sequence.

12. An apparatus for estimating noise detected in an environment of a magnetic resonance imaging system, the system comprising:

at least one transmit/receive coil configured to, when operated, produce a magnetic field configured to excite a magnetic resonance response, and to detect magnetic resonance signals;

at least one gradient coil for spatial encoding; and

at least one controller configured to:

repeatedly operate the at least one transmit/receive coil and the at least one gradient coil according to a first pulse sequence using a first spatial encoding to acquire a plurality of magnetic resonance signals;

estimate noise based, at least in part, on a comparison of the plurality of magnetic resonance signals.

13. The apparatus of claim 12 , wherein the at least one controller is configured to:

operate the at least one transmit/receive coil and the at least one gradient coil according to the first pulse sequence using the first spatial encoding to acquire at least one first magnetic resonance signal;

operate the at least one transmit/receive coil and the at least one gradient coil according to the first pulse sequence using the first spatial encoding to acquire at least one second magnetic resonance signal; and

estimate noise based, at least in part, on a comparison of the at least one first magnetic resonance signal and the at least one second magnetic resonance signal.

14. The apparatus of claim 13 , further comprising at least one auxiliary sensor, and wherein the at least one controller is configured to:

cause the at least one transmit/receive coil and the at least one auxiliary sensor to obtain multiple calibration measurements, respectively;

estimate a transform based, at least in part, on the respective multiple calibration measurements;

estimate noise present in a magnetic resonance signal received by the at least one transmit/receive coil based at least in part on the transform; and

suppress noise in the magnetic resonance signal using the noise estimate.

15. The apparatus of claim 13 , wherein the at least one controller is configured to align the at least one first magnetic resonance signal and the at least one second magnetic resonance signal using a phase shift.

16. The apparatus of claim 13 , wherein the at least one first magnetic resonance signal comprises a first plurality of averaged magnetic resonance signals acquired using the first spatial encoding.

17. The apparatus of claim 13 , wherein the at least one controller is configured to use both the at least one first magnetic resonance signal and the at least one second magnetic resonance signal to produce at least one magnetic resonance image.

18. The apparatus of claim 12 , wherein the at least one controller is configured to use the noise estimate to dynamically suppress noise in magnetic resonance signals obtained during operation of the magnetic resonance imaging system.