System and methods for detecting electromagnetic interference in patients during magnetic resonance imaging
A magnetic resonance (MR) imaging system, comprising a magnetics system having a plurality of magnetics components configured to produce magnetic fields for performing magnetic resonance imaging, and a sensor configured to detect electromagnetic interference conducted by a patient into an imaging region of the MR imaging system. The sensor may comprise at least one electrical conductor configured for electrically coupling to the patient. The MR imaging system may further comprise a noise reduction system configured to receive the electromagnetic interference from the sensor and to suppress electromagnetic interference in detected MR signals received by the MR imaging system based on the electromagnetic interference detected by the sensor.
1. A magnetic resonance (MR) imaging system, comprising:
a magnetics system having a plurality of magnetics components configured to produce magnetic fields for performing magnetic resonance imaging;
a noise reduction system configured to receive electromagnetic interference electrically coupled from a patient and compensate for the electromagnetic interference during imaging of the patient; and
a sensor configured to, when the patient is within capacitive coupling range of the sensor, capacitively couple the electromagnetic interference from the patient to the sensor and to provide the electromagnetic interference to the noise reduction system.
2. The MR imaging system of claim 1 , wherein:
the plurality of magnetics components include at least one radio frequency (RF) coil configured to, when operated, receive magnetic resonance signals emitted from a field of view of the MR imaging system; and
the noise reduction system is configured to reduce an impact of the electromagnetic interference on the magnetic resonance signals.
3. The MR imaging system of claim 1 , wherein the noise reduction system is configured to obtain samples of the electromagnetic interference and subtract a version of the samples from MR signals received via the magnetics system.
4. The MR imaging system of claim 3 , wherein the noise reduction system is configured to apply a transfer function to the samples and subtract transformed versions of the samples from the MR signals.
5. The MR imaging system of claim 4 , wherein the noise reduction system is configured to obtain calibration noise measurements of the electromagnetic interference and determine the transfer function using the calibration noise measurements.
6. The MR imaging system of claim 5 , wherein the noise reduction system is configured to estimate an amplitude and phase of the transfer function for each of a plurality of frequency bins of the transfer function using the calibration noise measurements.
7. An electric field detector (EFD) for a magnetic resonance (MR) imaging system, the EFD comprising:
at least one electrical conductor configured to, when positioned within capactive coupling range of a patient, capacitively couple electromagnetic interference from the patient to the at least one electrical conductor,
wherein the at least one electrical conductor is further configured to provide the electromagnetic interference to a noise reduction system of the MR imaging system.
8. The EFD of claim 7 , wherein the at least one electrical conductor is configured for placement proximate an imaging region that is within a magnetic component of the MR imaging system to capacitively couple to the patient when at least a portion of the patient's anatomy is positioned in the imaging region.
9. The EFD of claim 8 , wherein the EFD further comprises one or more flexible printed circuit boards (PCBs) having the at least one electrical conductor thereon.
10. The EFD of claim 9 , wherein the one or more flexible PCBs are configured for coupling to the noise reduction system of the MR imaging system via at least one electrical connector.
11. The EFD of claim 8 , wherein:
the at least one electrical conductor is configured for attaching to a surface of the magnetic component of the MR imaging system proximate the imaging region.
12. The EFD of claim 11 , further comprising:
electromagnetic shielding configured to be positioned between the magnetic component and the at least one electrical conductor,
wherein the magnetic component comprises at least one radio frequency coil, and the electromagnetic shielding is configured to be positioned between the at least one radio frequency coil and the at least one electrical conductor.
13. The EFD of claim 11 , wherein the magnetic component is a radio frequency (RF) component comprising a housing formed to accommodate a portion of the patient's anatomy in the imaging region, and the at least one electrical conductor is configured for attaching to at least one interior surface of the housing proximate the imaging region.
14. A method of compensating for electromagnetic interference introduced by a patient into an imaging region of a magnetic resonance (MR) imaging system, the method comprising:
using at least one electrical conductor of an electric field detector (EFD), when the at least one electrical conductor is positioned within capacitive coupling range of the patient, to capacitively couple the electromagnetic interference from the patient to the at least one electrical conductor; and
providing the electromagnetic interference from the sensor to a noise reduction system of the MR imaging system.
15. The method of claim 14 , wherein the at least one electrical conductor is placed proximate at least a portion of the imaging region that is within a magnetic component of the MR imaging system and capacitively couples to at least a portion of the patient's anatomy while the portion of the patient's anatomy is positioned in the portion of the imaging region.
16. The method of claim 15 , wherein:
the at least one electrical conductor is attached to a magnetic component of the MR imaging system; and
the method further comprises blocking at least some electrical coupling between the magnetic component and the at least one electrical conductor using electromagnetic shielding.
17. The method of claim 12 , further comprising:
obtaining samples of the electromagnetic interference from the EFD;
applying a transfer function to the samples; and
subtracting transformed versions of the samples from MR signals received via a magnetics system of the MR imaging system.
18. The method of claim 17 , further comprising obtaining calibration noise measurements of the electromagnetic interference and determining the transfer function using the calibration noise measurements.
19. The method of claim 18 , further comprising estimating an amplitude and phase of the transfer function for each of a plurality of frequency bins of the transfer function using the calibration noise measurements.
20. The MR imaging system of claim 1 , further comprising:
a magnetic component having a housing with an imaging region of the MR imaging system within the housing,
wherein the sensor is positioned proximate the imaging region within the housing of the magnetic component.