Reduction of Artifacts by Magnetic Field (B0) Active Shimming

Abstract

The electronic device 10 includes an electronic component 14, at least one conductive loop or winding 18 disposed around the electronic component, and an electronic controller 24 configured to: obtain (102) a magnetic field direction from a received ambient magnetic field measurement signal; determine (104) at least one magnetic field shim current based on the obtained magnetic field direction; and activate (108) the at least one conductive loop or winding to pass the determined at least one magnetic field shim current.

Description

Technical Field

[0001]

[0001] The following generally relates to imaging technology, magnetic resonance imaging technology, magnetic resonance image quality technology, magnetic field shim current technology, and related technologies.

Background Art

[0002]

[0002] Magnetic resonance imaging (MRI) scanners are increasingly adopting more electronic components within the magnet bore. These components use integrated circuit (IC) chips such as field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), microprocessors, memory chips, system on chip (SoC) chips, system in package (SiP) chips, etc. These IC chips include magnetic materials such as nickel used as a diffusion barrier with gold plating of wire bond bumps or flip chip bond bumps, and packaging materials or shielding materials. Exchange with non-magnetic materials is usually impossible or requires purchasing custom-made IC chips, which can be cost-ineffective. The magnetic materials of the IC chips can locally distort the static magnetic field (B0), which can cause imaging artifacts. Since these can be large chips (for example, an FPGA can be a 1.7 cm × 1.7 cm square), the amount of image distortion introduced by the IC chips can be large.

[0003]

[0003] The electronic components within the magnet bore also require power. Power cables can couple to the magnetic field gradient and / or radio frequency (RF) signals, and cable wiring problems can also occur. Battery power is an attractive alternative approach. However, batteries usually also contain magnetic materials that can potentially cause image distortion.

Summary of the Invention

Problems to be Solved by the Invention

[0004]

[0004] The following discloses specific improvements to overcome these and other problems.

Means for Solving the Problems

[0005]

[0005] In one aspect, an electronic device includes an electronic component, at least one conductive loop or winding disposed around the electronic component, an electronic controller configured to obtain a magnetic field direction from a received ambient magnetic field measurement signal, determine at least one magnetic field shimming current based on the obtained magnetic field direction, and activate at least one conductive loop or winding to flow the determined at least one magnetic field shimming current.

[0006]

[0006] In another aspect, an electronic device includes an IC chip, a magnetic field sensor configured to measure an ambient magnetic field measurement signal, a plurality of conductive loops or windings disposed around the IC chip, an electronic controller configured to obtain a magnetic field direction from the ambient magnetic field measurement signal measured by the magnetic field sensor, determine at least one magnetic field shimming current based on the obtained magnetic field direction, and activate the plurality of conductive loops or windings to flow the determined at least one magnetic field shimming current.

[0007]

[0007] In another aspect, a method for determining a magnetic field shimming current includes obtaining a magnetic field direction from a received ambient magnetic field measurement signal, determining at least one magnetic field shimming current based on the obtained magnetic field direction, and activating at least one conductive loop or winding to flow the determined at least one magnetic field shimming current.

[0008]

[0008] One advantage is to remove artifacts in the image caused by one or more magnetic components.

[0009]

[0009] Another advantage is to generate an active shimming current to cancel magnetic artifacts in the image.

[0010]

[0010] Another advantage is to generate equal but opposite magnetization to cancel magnetic artifacts in the image.

[0011]

[0011] Another advantage is to reduce the influence of magnetic components on the image by generating corresponding shimming currents.

[0012]

[0012] A given embodiment may or may not provide any of the aforementioned advantages, and may provide one, two, or more, or all of them, and / or may provide other advantages that will be apparent to those skilled in the art upon reading and understanding the present disclosure.

[0013]

[0013] The present disclosure takes the form of various components and component arrangements, as well as various steps and step arrangements. The drawings are for the sole purpose of illustrating the preferred embodiments and should not be construed as limiting the present disclosure.

Brief Description of the Drawings

[0014]

Figure 1

[0014] FIG. 1 is a diagram showing an exemplary embodiment of an electronic device for an MRI system according to one aspect.

Figure 2

[0015] FIG. 2 is a diagram showing another exemplary embodiment of an electronic device for an MRI system according to one aspect.

Figure 3

[0016] FIG. 3 is a diagram showing an exemplary flowchart operation of the devices of FIGS. 1 and 2.

Modes for Carrying Out the Invention

[0015]

[0017] The systems and methods disclosed herein utilize the observation that the effect of an IC chip (or other magnetic object) in a B0 magnetic field can be modeled as a bound current flowing on the surface of the IC chip that generates a concentrated magnetic moment M. In one exemplary embodiment, conductors or loops are wound around the outside of the IC chip, and a current is passed through these conductors to cancel the magnetic moment M.

[0016]

[0018] In some embodiments disclosed herein, the ambient magnetic field (i.e., the magnetic field in which the IC chip is embedded) is measured using a three-axis hall sensor, or other magnetic field sensors mounted on or attached with the magnetic object that can measure the magnetic field in three dimensions (3D). However, it is not appropriate to simply null the measured magnetic field in order to remove image artifacts. The goal is not to remove the magnetic field, but to return B0 to a non-distorted value. The distorted magnetic moment M introduced by the magnetic material in the IC chip is typically small compared to the magnitude of the B0 magnetic field, i.e., |M| << |B0|. Further, both B0 and M are vectors, and they are oriented in different directions. Therefore, it is difficult to determine the magnetic moment M vector that is removed by the magnetic field measurement.

[0017]

[0019] To improve these problems, in some embodiments disclosed herein, the current applied by the conductors or loops to compensate for the B0 distortion is pre-calibrated using simulations or experiments for various spatial orientations of the IC chip corresponding to the B0 vector. For example, the IC chip is placed in the bore at a specific orientation, an image is acquired, and the compensation loop current is adjusted until the image artifacts are minimized. A similar approach can be performed using an electromagnetic simulator aimed at adjusting the compensation loop current until the distortion is removed. This calibration is performed at various orientations.

[0018]

[0020] After that, the IC chip is deployed together with a 3D Hall sensor. The Hall sensor is only used to determine the orientation of the IC chip corresponding to the B0 field, and the applied compensating loop current is the calibration current for that orientation. (If there are several different discrete orientation calibrations, interpolation is applied).

[0019]

[0021] Advantageously, the Hall sensor does not even need to be mounted on or in close proximity to the IC chip. Rather, the Hall sensor only needs to be mounted in a fixed orientation relative to the IC chip. Usually, it is simplest to mount the Hall sensor on the same PCB on which the IC chip is mounted. Furthermore, since the magnetic field measurement is only used to determine the direction of the B0 magnetic field, the magnetic field distortion at the Hall sensor due to the magnetic moment M generated by the IC chip (when close to the Hall sensor) usually has a negligible effect on the determined direction of B0 due to the difference in magnitude, i.e., |B0| >> |M|.

[0020]

[0022] In some embodiments disclosed herein, the IC chip is a programmable IC chip such as an FPGA or a microprocessor. In these cases, a controller for driving the loop compensation current can be implemented on the IC chip itself. Since the conductive loop is external to the IC chip, it can be added to an off-the-shelf IC chip. Furthermore, the compensating loop current is, in some embodiments, a DC current that can be drawn from a digital power rail (e.g., the V CC -GND potential difference). Thus, all IC chips on the board are effectively "self-shielded" with respect to the distortion of the B0 magnetic field by the necessary on-board control program, the surrounding conductive loop, and a single 3D Hall sensor (or other 3D magnetic field sensor) mounted on the board.

[0021]

[0023] The proposed design can also be easily deployed to MRI scanners that apply different B0 strengths. In this case, in addition to determining the B0 orientation, the hall sensor also determines its magnitude |B0|. It is expected that the calibration compensation loop current needs to scale in proportion to |B0|. Alternatively, the calibration of the compensation current can be performed for several different standard field strengths (e.g., 1.5 tesla, 3.0 tesla).

[0022]

[0024] In some embodiments disclosed herein, to save power, the compensation loop current can be turned off when the device is not performing imaging.

[0023]

[0025] In some embodiments disclosed herein, using the disclosed approach, the magnitude of the ambient magnetic field can be measured in real time, and the magnetic field gradient can be compensated by compensating for changes in that magnitude as a function of time. A further possible variation involves the measurement of the derivative d|B0| / dt, which should be proportional to the eddy currents induced in the ground plane of the PCB. In this case, the calibration of the experiment or simulation is performed on the IC chips on the PCB, and the eddy current compensation as a function of d|B0| / dt is calibrated by applying different magnetic field circulation patterns expected to be encountered during MRI imaging.

[0024]

[0026] In other embodiments disclosed herein, using the disclosed approach, the magnetic field gradient caused by the effect of a moving magnetic component over time can be compensated. Such movement causes the spatial gradient dB / dx(t) of the magnetic moment M to vary over time, generating various magnetic fields in the IC chip.

[0025]

[0027] Exemplary embodiments provide artifact reduction for IC chips, but the disclosed approach is also applicable to other devices placed within the MRI bore that include magnetic materials such as on-board batteries, large capacitors or inductors, shields, and / or packaging materials.

[0026]

[0028] As used herein, the term "ambient magnetic field" (and variations thereof) refers to the magnetic field in the surrounding region or environment surrounding the circuit to which the electronic component is attached. Put another way, the ambient magnetic field is the magnetic field in which the circuit is embedded. In the context of MRI, the ambient magnetic field is typically the static B0 magnetic field generated by a (usually superconducting) magnet placed in the MRI scanner, or the B0 magnetic field modified by a magnetic field gradient superimposed by the magnetic field gradient coils of the MRI scanner. It should be noted that, as used herein, the "ambient magnetic field" typically does not refer to the Earth's magnetic field. The influence of the Earth's magnetic field on the ambient magnetic field within the MRI bore is completely negligible. For example, the Earth's magnetic field at the Earth's surface is typically about 25 - 65 microteslas, while the standard B0 magnetic field values of some commercially available MRI scanners are 0.23 tesla, 1.5 tesla, 3.0 tesla, or higher.

[0027]

[0029] As used herein, a conductive loop (and variations thereof) is a single conductor turn, while a conductive winding (and variations thereof) includes two or more conductor turns, such as a solenoid (more generally, the two or more conductor turns do not need to have the same radius as in the case of a solenoid), where the induced magnetic fields couple additively.

[0028]

[0030] FIG. 1 shows one exemplary embodiment of an electronic device 10 for an associated medical imaging device (e.g., an MRI scanner) 12. The electronic device 10 includes an electronic component 14. In some embodiments, the electronic component 14 is a battery 15, such as an exemplary flat cylindrical button battery. In other embodiments, the electronic component 14 is an IC chip 16, such as an FPGA or a microprocessor chip.

[0029]

[0031] The electronic device 10 also includes at least one conductive loop or winding 18 disposed around the electronic component 14. The at least one conductive loop or winding 18 is configured to carry a magnetic field shimming current. As illustrated in FIG. 1, the at least one conductive loop or winding 18 comprises three conductive loops or windings 18 disposed around the electronic component 14, although any suitable number of loops or windings can be used. The three loops 18 illustrated in FIG. 1 have loop normals that are mutually orthogonal (e.g., respective normal vectors to respective planes in which the respective loops are disposed orthogonally to each other). Such an arrangement of three mutually orthogonal loops enables compensation regardless of the orientation of the electronic device 10 corresponding to the direction of the ambient magnetic field. However, it is contemplated to use less than three loops, for example, if the approximate orientation of the electronic device corresponding to the B0 magnetic field is known in advance, only two, or perhaps only one conductive loop may be sufficient. As an example of such a situation, a head coil designed to be deployed in relation to a patient in the prone or supine position has a substantially predefined orientation corresponding to B0, and thus an IC chip attached to that head coil also has a substantially predefined orientation corresponding to B0.

[0030]

[0032] Continuing to refer to FIG. 1 and as shown with reference to FIG. 2, the electronic device 10 also includes a magnetic field sensor 20 configured to generate an ambient magnetic field signal indicating the magnitude and direction of the ambient magnetic field (in 3D). In some examples, the magnetic field sensor 20 includes a three-axis Hall effect sensor, although other types of magnetometers, such as magnetoresistive sensors, fluxgate magnetometers, etc., are contemplated as the magnetic field sensor 20. The electronic device 10 also includes (or, alternatively, is disposed on) a printed circuit board (PCB) 22 to which the electronic components 14 are attached. As shown in FIG. 2, the electronic components 14 and the magnetic field sensor 20 are attached to the (same) PCB 22, while the three conductive loops 18 surround the electronic components. However, in some embodiments, the magnetic field sensor 20 need not be attached to the PCB 22, but rather need only be attached in a fixed orientation relative to each of the electronic components 14. (This fixed orientation is achieved when the electronic components 14 and the magnetic field sensor 20 are attached to the same PCB 22, assuming the PCB 22 is not a flexible PCB.)

[0031]

[0033] The electronic device 10 also includes an electronic controller 24 (also referred to as a processor or control unit) configured to determine a biasing current to supply to each of the conductive loops or windings 18. The electronic controller is electrically connected to at least one of the conductive loops or windings 18 and, in some embodiments, is electrically connected to the magnetic field sensor 20.

[0032]

[0034] The conductive loop or winding 18 can be manufactured by various techniques. In one approach, the conductive loop or winding 18 includes one or more turns of wire wound around the electronic component 14. This approach is convenient for retroactively adding the conductive loop or winding 18 to an off-the-shelf electronic component. In another approach, the conductive loop or winding 18 includes an electrical trace or set of traces deposited on the housing of the electronic component 14, for example, using vacuum evaporation and performing appropriate masking during evaporation, or using photolithography to depict the electrical trace. In another approach, one conductive loop or winding 18 is formed as an electrical PCB trace of the PCB 22 arranged to surround the location where the electronic component 14 is attached to the PCB 22. (This approach generally only works for conductive loops or windings 18 whose plane is parallel to the plane of the PCB 22.) In another approach, one conductive loop or winding 18 is formed as an electrical trace manufactured on the silicon wafer of the IC chip during the manufacture of the IC chip 14. (This assumes that the electronic component 14 is an IC chip and generally only works for conductive loops or windings 18 whose plane is parallel to the plane of the silicon wafer and cannot be used for retrofitting an off-the-shelf IC chip.) In yet another approach, the electronic component 14 can be housed in an external housing (not shown) that includes the conductive loop or winding 18. This approach is suitable, for example, in the case of the battery 15 of FIG. 1, where the housing is a battery housing or receptacle in which the battery 15 is installed. In this way, off-the-shelf batteries can be used. These are just some non-limiting exemplary approaches for providing the conductive loop or winding 18.

[0033]

[0035] Each conductive loop or winding 18 should be arranged relative to the electronic component 14 such that the induced magnetic field generated by the current flowing through the conductive loop or winding 18 passes through the electronic component 14. This is easily achieved when the conductive loop or winding 18 is wound around the electronic component 14. However, it can be realized by other means. For example, in the aforementioned embodiment where the conductive loop or winding 18 is formed as a conductive PCB trace on the PCB 22 surrounding the mounting position of the electronic component 14, the plane of the conductive PCB trace is spatially offset from the electronic component 14, but the magnetic field generated by the current flowing through the surrounding PCB traces still passes through the electronic component 14. Generally, it is desirable for the conductive loop or winding 18 to enclose or be closely coupled to the electronic component 14. Thus, in the example of FIG. 2, the PCB trace surrounding the outer periphery of the PCB 22 generates a magnetic field passing through the electronic component 14, but only a very small part of that magnetic field actually passes through the electronic component, making the strain compensation very inefficient.

[0034]

[0036] The operable electrical connection of the electronic controller 24 to the conductive loop or winding 18 can be made in various ways. When the electronic controller 24 is attached to the PCB 22, conductive PCB traces of the PCB 22 can be provided (during the manufacture of the PCB 22) to connect the wire bond or surface mount contact pads of the electronic controller 24 to the bond pads where the conductive loop or winding 18 is soldered. In an embodiment where the electronic controller 24 is integrally mounted on the IC chip 14, for example, the surface mount pads (not shown) of the IC chip 14, which are programmed to direct the drive current by appropriate controller programming implemented on the IC chip 14 including, for example, an FPGA or a microprocessor, are connected to the conductive loop or winding 18. The digital power rail (e.g., V CC-In embodiments where the (GND potential difference) provides power to drive the conductive loop or winding 18, no additional power source is required to drive the provision of drive power for the conductive loop or winding 18. Since the magnetization M due to the magnetic material in the IC chip or other normal non-magnetic components is expected to be small, the digital power rail is expected to be sufficient for many specific applications. If additional power is required, a separate power source is supplied, and in that case, the operable electrical connection of the electronic controller 24 to the conductive loop or winding 18 is made appropriate by a power control circuit configuration in which the electronic controller 24 controls the power control circuit configuration to control the amount of power supplied to the conductive loop or winding 18. Again, these are some non-limiting exemplary examples.

[0035]

[0037] Continuing to refer to FIGS. 1 and 2 and further referring to FIG. 3, as shown, the electronic controller 24 is configured to execute a method or process 100 for determining the magnetic field shim current. To do so, the electronic processor 24 obtains the magnetic field direction from the received ambient magnetic field measurement signal (102), determines at least one magnetic field shim current based on the obtained magnetic field direction (104), and activates at least one conductive loop or winding 18 to pass the determined at least one magnetic field shim current (106).

[0036]

[0038] In some embodiments, the operation 102 of obtaining includes measuring or determining the magnetic field direction using the magnetic field sensor 20. In other embodiments, the operation 102 of obtaining includes measuring or determining the magnetic field strength of the ambient magnetic field using the magnetic field sensor 20. In this example, the operation 104 of determining includes determining at least one magnetic field shim current using the magnetic field direction (and optionally the magnetic field strength). If the magnitude of the ambient magnetic field is known in advance (e.g., when the electronic device 10 is used with a standard 3-tesla magnet), the only variable is the orientation of the B0 magnetic field. An appropriate shim current calibration 105 is shown in FIG. 3. Here, each row of the calibration table is in the form of a tuple (DX,I1X,I2X,I3X) Store it, where "DX" indicates the orientation of the (ambient) B0 magnetic field, and I1X, I2X, I3X indicate the shim currents appropriate for the respective orientations "DX" of the (exemplary) three conductive loops or windings 18. If the measured B0 orientation does not exactly match any table entry, the closest entry can be selected or interpolation between the two closest entries can be performed. If the ambient magnetic field strength is not known in advance, this can be obtained from the magnetic field measurement and the calibration of the shim current can be (DX,MY,I1XY,I2XY,I3XY) corrected to here, where "MY" indicates the ambient magnetic field strength and the appropriate shim current for each loop or winding is parameterized by both the direction (X) and the magnitude (Y). As described above, the shim current calibration 105 can be appropriately generated offline either experimentally (e.g., by placing the device in the MRI in various orientations and adjusting the shim current until the image distortion is minimized for each orientation) or by simulation (by the same simulation as in the electromagnetic simulator). In a further embodiment, the act of obtaining 102 includes determining the time derivative of the magnetic field strength of the ambient magnetic field and using this time derivative (along with the direction) to determine at least one magnetic field shim current in act 104. The time derivative of the magnetic field induces eddy currents in the ground plane of the PCB 22, which in turn induce magnetic moments that distort the image and these are shimmed.

[0037]

[0039] In yet other embodiments, activation operation 106 includes activating at least one conductive loop or winding 18 only when the MRI scanner 12 is acquiring imaging data. This involves providing information to the electronic controller 24 about when imaging is being performed. This information is provided, for example, by an MRI imaging controller (not shown) of the MRI scanner 12. In another approach, detection of the time-varying magnetic field by the magnetic field sensor 20 provides an indication of when imaging is being performed. When imaging is not being performed, the ambient magnetic field needs to be static because no magnetic field gradient is being applied. In contrast, during imaging, the applied magnetic field gradient dynamically varies the ambient magnetic field, which is detected by the magnetic field sensor 20 to determine when imaging is being performed. Since a portion of the magnetic resonance imaging sequence may not involve a magnetic field gradient, this approach preferably turns on the shim current as soon as a dynamically changing ambient magnetic field is detected and turns it off only after a certain time after the ambient magnetic field has become static (e.g., wait 1 or 2 seconds after the magnetic field has become static and then turn off the shim current).

[0038]

[0040] In some embodiments, the IC chip 14 includes an electronic processor or control unit such as a microprocessor, a microcontroller, or an FPGA. For example, the IC chip 14 itself is programmed to perform the acquisition operation 102, the determination operation 104, and the activation operation 106. In this embodiment, the microprocessor or microcontroller or FPGA 14 receives power only via a power pin of the microprocessor or microcontroller or FPGA that supplies operating power to the microprocessor or microcontroller or FPGA.

[0039]

[0041] At least the magnetic field shim current, in some embodiments, is from a digital power rail (e.g., V CCIt is a DC current that can be drawn from the (-GND potential difference). Therefore, all the electronic components 14 attached to the PCB 22 can be effectively "self-shielded" with respect to distorting the ambient magnetic field by adding the necessary on-board control program and the surrounding conductive loop, as well as a single magnetic field sensor 20 attached to the PCB 22.

[0040]

[0042] In other embodiments, the electronic component 14 includes a plurality of electronic components (for example, a plurality of batteries, a plurality of IC chips, a combination of one or more batteries and one or more IC chips, etc.) each attached to the PCB 22. Each electronic component 14 has a corresponding at least one conductive loop or winding 18 disposed around it. The electronic controller 24 is configured to perform an acquisition operation 102, a determination operation 104, and an activation operation 106 for each electronic component 14.

[0041]

[0043] When determining at least one magnetic shim current in operation 104, the value of the at least one magnetic shim current needs to return the ambient magnetic field to a non-distorted value rather than removing the ambient magnetic field. However, it is not clear from the measurement by the magnetic field sensor 20 what such a non-distorted value is.

[0042]

[0044] To solve this, the electronic device 10 can be calibrated for various orientations of the electronic component 14 with respect to the ambient magnetic field (for example, by placing the electronic component in the bore of the MRI scanner 12, acquiring an image, and adjusting the current of at least one conductive loop or winding 18 until the artifact is minimized or eliminated). Then, when the magnetic field sensor 20 determines the orientation of the device corresponding to the ambient magnetic field, the applied compensation loop current is the current for the calibration of that orientation.

[0043]

[0045] This disclosure has been described with reference to preferred embodiments. Upon reading and understanding the above detailed description, others may envision modifications and changes. Exemplary embodiments are intended to be construed to include all such modifications and changes as long as they fall within the scope of the appended claims or their equivalents. Embodiment 1 An electronic component, At least one conductive loop or winding disposed around the electronic component, An electronic device comprising an electronic controller, The electronic controller, Obtains the magnetic field direction from the received ambient magnetic field measurement signal, Based on the obtained magnetic field direction, determines at least one magnetic field shim current, An electronic device that activates at least one of the conductive loops or windings to pass at least one of the determined magnetic field shim currents. Embodiment 2 The electronic device according to Embodiment 1, wherein the electronic component is an integrated circuit (IC) chip. Embodiment 3 The IC chip is a microprocessor or a microcontroller or a field programmable gate array (FPGA), The electronic controller comprises the microprocessor or the microcontroller or the FPGA, The electronic controller, Obtains the magnetic field direction from the received ambient magnetic field measurement signal, Based on the obtained magnetic field direction, determines at least one of the magnetic field shim currents, The electronic device according to Embodiment 2, which is programmed to activate at least one of the conductive loops or windings to pass at least one of the determined magnetic field shim currents. Embodiment 4 The electronic device according to Embodiment 3, wherein the microprocessor or the microcontroller or the FPGA does not receive power other than through the power pin of the microprocessor or the microcontroller or the FPGA that supplies operating power to the microprocessor or the microcontroller or the FPGA. Embodiment 5 The electronic device according to Embodiment 1, wherein the electronic component is a battery. Embodiment 6 The electronic device according to any one of Embodiments 1 to 5, wherein at least one of the conductive loops or windings disposed around the electronic component comprises three conductive loops or windings having loop normals orthogonal to each other. Embodiment 7 The electronic device further comprises a printed circuit board (PCB) to which the electronic component is attached and a magnetic field sensor attached to the PCB, and the magnetic field sensor generates the ambient magnetic field measurement signal received by the electronic controller. The electronic device according to any one of Embodiments 1 to 6. Embodiment 8 The magnetic field sensor is the electronic device according to Embodiment 7, which includes a Hall effect sensor. Embodiment 9 The electronic components have a plurality of electronic components, each of the electronic components is attached to the PCB, and each of the electronic components has at least one conductive loop or winding arranged around the electronic component. The electronic controller obtains the magnetic field direction from the ambient magnetic field measurement signal received from the magnetic field sensor. Based on the obtained magnetic field direction, for each of the plurality of electronic components, at least one magnetic field shimming current is determined. The electronic device according to Embodiment 7 or 8, which activates at least one of the conductive loops or windings of each of the plurality of electronic components to pass at least one of the magnetic field shimming currents determined for the electronic component. Embodiment 10 The electronic device according to any one of Embodiments 7 to 9, wherein at least one of the conductive loops or windings includes a conductive loop or winding provided with a printed circuit of the PCB surrounding the electronic component attached to the PCB. Embodiment 11 The electronic device according to any one of Embodiments 1 to 10, wherein the electronic controller activates at least one of the conductive loops or windings to pass at least one of the determined magnetic field shimming currents only when a related magnetic resonance imaging (MRI) scanner is acquiring imaging data. Embodiment 12 The electronic controller further obtains the magnetic field strength from the received ambient magnetic field measurement signal. The electronic device according to any one of Embodiments 1 to 11, which determines at least one of the magnetic field shimming currents based on the obtained magnetic field direction and the obtained magnetic field strength. Embodiment 13 An integrated circuit (IC) chip, a magnetic field sensor for measuring an ambient magnetic field measurement signal, a plurality of conductive loops or windings arranged around the IC chip, and an electronic device including an electronic controller, wherein the electronic controller obtains the magnetic field direction from the ambient magnetic field measurement signal measured by the magnetic field sensor, determines at least one magnetic field shimming current based on the obtained magnetic field direction, and activates a plurality of the conductive loops or windings to pass at least one of the determined magnetic field shimming currents. Embodiment 14 The IC chip is a microprocessor or a microcontroller or a field programmable gate array (FPGA), and is the electronic device according to Embodiment 13, programmed to execute the operation to be acquired, the operation to be determined, and the operation to be activated. Embodiment 15 The electronic device according to Embodiment 13 or 14, further comprising a printed circuit board (PCB) to which at least one of the IC chip and the magnetic field sensor is attached. Embodiment 16 The electronic device according to Embodiment 15, wherein the plurality of conductive loops or windings comprise the printed circuit of the PCB surrounding the IC chip. Embodiment 17 The electronic device according to any one of Embodiments 13 to 16, wherein the magnetic field sensor comprises a Hall effect sensor. Embodiment 18 The electronic controller further acquires a magnetic field intensity from the ambient magnetic field measurement signal measured by the magnetic field sensor, and determines at least one of the magnetic field shim currents based on the acquired magnetic field direction and the acquired magnetic field intensity. The electronic device according to any one of Embodiments 14 to 17. Embodiment 19 The electronic controller further acquires a time derivative of the magnetic field intensity from the ambient magnetic field measurement signal measured by the magnetic field sensor, and determines at least one of the magnetic field shim currents based on the acquired magnetic field direction and the acquired time derivative of the magnetic field intensity. The electronic device according to any one of Embodiments 14 to 18. Embodiment 20 A method for determining a magnetic field shim current, comprising: acquiring a magnetic field direction from a received ambient magnetic field measurement signal; determining at least one magnetic field shim current based on the acquired magnetic field direction; and activating at least one conductive loop or winding to pass the determined at least one magnetic field shim current.

Claims

1. An electronic component, At least one conductive loop or winding disposed around the electronic component, An electronic device comprising an electronic controller, wherein the electronic controller obtains a magnetic field direction from a received ambient magnetic field measurement signal, determines at least one magnetic field shimming current based on the obtained magnetic field direction, activates at least one of the conductive loops or windings to pass at least one of the determined magnetic field shimming currents, and the electronic component is a battery. The electronic device.

2. An electronic component, At least one conductive loop or winding disposed around the electronic component, A printed circuit board (PCB) to which the electronic component is attached, An electronic device comprising an electronic controller, wherein the electronic component has a plurality of electronic components, each of the electronic components being attached to the PCB, and each of the electronic components having at least one conductive loop or winding disposed around the electronic component, the electronic controller obtains a magnetic field direction from a received ambient magnetic field measurement signal, determines at least one magnetic field shimming current for each of the plurality of electronic components based on the obtained magnetic field direction, and activates at least one of the conductive loops or windings of each of the plurality of electronic components to pass at least one of the determined magnetic field shimming currents for the electronic component. The electronic device.

3. An electronic component, At least one conductive loop or winding disposed around the electronic component, An electronic device comprising an electronic controller, wherein the electronic controller, obtains a magnetic field direction from a received ambient magnetic field measurement signal, determines at least one magnetic field shim current based on the obtained magnetic field direction, activates at least one of the conductive loops or windings to pass the determined at least one magnetic field shim current, and the electronic controller activates at least one of the conductive loops or windings to pass the determined at least one magnetic field shim current only when a related magnetic resonance imaging (MRI) scanner is acquiring imaging data. **Claim 4** An electronic device comprising an electronic component, at least one conductive loop or winding disposed around the electronic component, and an electronic controller, wherein the electronic controller, obtains a magnetic field direction from a received ambient magnetic field measurement signal to determine an orientation of the electronic component with respect to the magnetic field direction, determines at least one magnetic field shim current based on the determined orientation of the electronic component with respect to the magnetic field direction and a calibration table indicating calibration of a magnetic field shim current with respect to the magnetic field direction, and activates at least one of the conductive loops or windings to pass the determined at least one magnetic field shim current. **Claim 5** The electronic device according to claim 2, 3, or 4, wherein the electronic component is a battery and / or an integrated circuit (IC) chip. **Claim 6** The IC chip is a microprocessor or a microcontroller or a field programmable gate array (FPGA), the electronic controller comprises the microprocessor or the microcontroller or the FPGA, and the electronic controller, Obtaining the magnetic field direction from the received ambient magnetic field measurement signal; determining at least one of the magnetic field shim currents based on the obtained magnetic field direction; The electronic device of claim 5 , programmed to activate at least one of the conductive loops or windings to carry at least one of the determined magnetic field shim currents.

7. 7. The electronic device of claim 6, wherein the microprocessor or microcontroller or FPGA receives no power other than through power pins of the microprocessor or microcontroller or FPGA which provide operating power to the microprocessor or microcontroller or FPGA.

8. 8. The electronic device of claim 1, wherein the at least one conductive loop or winding disposed around the electronic component consists of three conductive loops or windings having mutually orthogonal loop normals.

9. 9. The electronic device of claim 2, or any one of claims 5 to 8 that directly or indirectly cites claim 2, further comprising a magnetic field sensor attached to the PCB, the magnetic field sensor generating the ambient magnetic field measurement signal that is received at the electronic controller.

10. The electronic device of claim 9 , wherein the magnetic field sensor comprises a Hall effect sensor.

11. 11. The electronic device of claim 2, or any one of claims 5 to 10 that directly or indirectly cites claim 2, wherein at least one of the conductive loops or windings comprises a conductive loop or winding with a printed circuit of the PCB that surrounds the electronic component mounted on the PCB.

12. The electronic controller further comprises: Obtaining a magnetic field strength from the received ambient magnetic field measurement signal; 12. The electronic device of claim 1, further comprising: a first shim current determining means for determining at least one of the magnetic field shim currents based on the determined magnetic field direction and the determined magnetic field strength.

13. The electronic controller further comprises: Obtaining a time derivative of a magnetic field strength from the ambient magnetic field measurement signal measured by the magnetic field sensor; 13. The electronic device of claim 9, or any one of claims 10 to 12 directly or indirectly citing claim 9, for determining at least one magnetic field shim current based on the obtained magnetic field direction and the obtained time derivative of the magnetic field strength.

14. 1. A method for determining magnetic field shim currents, comprising: obtaining a magnetic field direction from the received ambient magnetic field measurement signals and determining an orientation of the electronic component relative to said magnetic field direction; determining at least one magnetic field shim current based on the determined orientation of the electronic component relative to the magnetic field direction and a calibration table indicating a calibration of magnetic field shim currents relative to the magnetic field direction; and activating at least one conductive loop or winding to carry the determined at least one magnetic field shim current.

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