Methods for noise reduction on measurement domain

Abstract

Disclosed herein are methods and systems for noise reduction in the measurement domain. The method may be used in situations where MRIs are susceptible to EMI noise. The method may also be used in cases where T2 weighted or fluid-attenuated inversion recovery (FLAIR) imaging contrasts are used. The method may also use a CAD algorithm, or alternatively, a GAD algorithm in reducing noise.

Description

Attorney Docket No. 59984-716601METHODS FOR NOISE REDUCTION ON MEASUREMENT DOMAINCROSS-REFERENCE

[0001] This application claims the benefit of U. S. Provisional Application No. 63 / 750,253, filed January 27, 2025, which is incorporated herein in its entirety.BACKGROUND

[0002] Standard magnetic resonance imaging (MRI) scanners operate in Faraday shielded rooms which can prevent external electromagnetic interference (EMI) from distortingthe diagnostic images and prevent the MRI's own electromagnetic radiation from disrupting external medical devices. Low-field MRI scanners, particularly those designed for portable point-of-care use, are designed shielding-free for enhancing mobility, making them susceptible to EMI.SUMMARY

[0003] Disclosed herein are methods of removing electromagnetic interference (EMI) in a measurement domain. A method for removing EMI noise in the measurement domain is provided. In some embodiments, the method may be used when MRI data is acquired in shielding-free low-field MRI scanners or RF shielding leakage. In some implementations, the method may comprise inputting primary coil data and noise coil k-space measurement data, wherein the measurement data may be described as Xt, i = 0, 1 ••• Nc; wherein at a time t, t = 1 ••• T. In some implementations, the method may comprise: inputting a primary coil and noise coils k-space measurement data, wherein the measurement data is described as x ° i = 0, 1 ••• Nc; wherein at a time t, t = 1 ••• T, the method further comprises: constructing a convolution matrix G^ from noise coils {x^}, i = 1 ••• Nc; wherein at each coil i, i = 0 ••• Nc, the further steps comprise: computing transfer functions for each coil y^ = min 11 G^Yt — YiX^ 11, wherein each coil is represented by i = 0 ••• Nc; estimating EMI signal in each coil f* «- G^Y^-, wherein each coil is represented by i = 0 ••• Nc; computing transfer functions for each coil y^ = min || G^yi ~wherein each coil is represented by i = 0 ••• Nc;Yiestimating EMI signal in each coil<- G®y[(t), wherein each coil is represented by i = 0 ••• Nc; determining EMI mitigated signal in each coil X'^ «- X^ —, wherein each coil is represented by i = 0 ••• Nc; concatenating each noise coils as multi-channel data {X'^}^;applying an anisotropic diffusion algorithm on an EMI mitigated signal X⃗'0(T)for the primaryAttorney Docket No. 59984-716601coil, wherein the EMI mitigated signal comprises a real part and an imaginary part, wherein the curvature anisotropic diffusion algorithm is applied separately to the real and imaginary parts of the EMI mitigated signal; resetting the primary coil; and outputting an updated noise reduced primary coil k-space data X „ ’.The EMI mitigated signal may comprise a real part and an imaginary part. In some implementations, a curvature anisotropic diffusion algorithm may be applied separately to the real and imaginary parts of the EMI mitigated signal. In some implementations, the method may include resetting a primary coil and outputting an updated noise reduced primary coil k-space data X'^.

[0004] In some embodiments, disclosed herein are methods where the anisotropic diffusion algorithm comprises a curvature anisotropic diffusion (CAD) algorithm.

[0005] In some embodiments, disclosed herein are methods where anisotropic diffusion algorithm comprises a gradient anisotropic diffusion (GAD) algorithm.

[0006] In some embodiments, disclosed herein are methods further comprising an outer loop, wherein the outer loop is run T times.

[0007] In some embodiments, disclosed herein are methods further comprising an inner iterative updating loop embedded inside the outer loop, wherein the inner iterative updating loop is run through all the noise coils from 0 to Nc.

[0008] In some embodiments, disclosed herein are methods wherein the transfer functions are solved for each noise coil, and each coil updates its own EMI mitigated data in the inner loop.

[0009] In some embodiments, disclosed herein are methods wherein the transfer functions for each noise coil are computed two times.

[0010] In some embodiments, disclosed herein are methods wherein a first calculation is computed based on original measurement data X^.

[0011] In some embodiments, disclosed herein are methods wherein a second calculation gets an accurate transfer function that is computed based on the updated EMI signal in each coil.

[0012] Described herein are computer-implemented systems comprising: at least one computer processor, and one or more non-transitory computer-readable storage media storing instructions that, when executed by the at least one processor, cause the system to perform electromagnetic interference (EMI) removal operations comprising: detecting, from a primary coil, primary coil data and, from a plurality of noise coils, noise coil measurement data, wherein the measurement data is represented as x ° i = 0, 1 ••• Ncfor each time t, where t = 1 ••• T, constructing a convolution matrix from the noise coil measurement data for each of the noise coils {X⃗i(t)}, i = 1 ••• Nccomputing, for each noise coil, a first transfer function y^ =Attorney Docket No. 59984-716601min || G^γ⃗i— X⃗i(t)||; estimating, for each noise coil, an EMI signal as η⃗i(t)← G(t)γ⃗i(t); computing, for each noise coil, a refined transfer function γ⃗i(t)= min || G(t)γ⃗i− η⃗i(t)||estimating, for each noise coil, a refined EMI signal as v'^determining, for each noise coil, an EMI mitigated signal X'^ «- X^ — v'^,' concatenating the EMI mitigated signal from each noise coil as multi-channel dataapplying an anisotropic diffusion algorithm to an EMI mitigated primary coil signalX „, wherein the EMI mitigated primary coil signal comprises a real part and an imaginary part, wherein the anisotropic diffusion algorithm is applied separately to the real and imaginary parts; and outputting an updated noise reduced — > / 'T'>\primary coil k-space data X „ ’.

[0013] In some embodiments, disclosed herein are systems wherein the anisotropic diffusion algorithm comprises a curvature anisotropic diffusion (CAD) algorithm. In some embodiments, disclosed herein are systems wherein the anisotropic diffusion algorithm comprises a gradient anisotropic diffusion (GAD) algorithm. In some embodiments, disclosed herein are systems, wherein the EMI removal operations are performed in an outer loop, wherein the outer loop is run T times. In some embodiments, disclosed herein are systems wherein an EMI removal operations further comprise an inner iterative updating loop embedded inside the outer loop, wherein the inner iterative updating loop runs through each of the noise coils from 0 to Nc. In some embodiments, disclosed herein are systems wherein the transfer functions are solved for each noise coil, and each coil updates its own EMI mitigated data in the inner loop. In some embodiments, disclosed herein are systems wherein the EMI removal operations further comprise computing a transfer function for each noise coil two times. In some embodiments, disclosed herein are systems wherein a first computation of a transfer function for each noise coil is based on original measurement data X^\ In some embodiments, disclosed herein are systems wherein a second computation of a transfer function for each noise coil is based on the updated EMI signal in each coil η⃗i'(t).

[0014] Disclosed herein are computer-implemented methods for removing EMI in measurement data. In some embodiments, the methods comprise: receiving measurement data from a primary sensor; receiving interference data from one or more auxiliary sensors; estimating an interference model based at least in part on the interference data from the auxiliary sensors; generating an interference estimate using the interference model and the auxiliary sensor data; iteratively refining the interference model using the interference estimate and the auxiliary sensor data; and generating interference-reduced measurement data based on the refined interference model.Attorney Docket No. 59984-716601

[0015] In some embodiments, disclosed herein are methods wherein iteratively refining the interference model comprises computing one or more transfer functions for each auxiliary sensor, and updating the interference estimate based on the transfer functions.

[0016] In some embodiments, disclosed herein are methods wherein iteratively refining the interference model comprises computing a first transfer function for each auxiliary sensor based on inference data from each auxiliary sensor to produce a first interference estimate; and computing a second transfer function for each auxiliary sensor based on a previously estimated interference estimate.

[0017] In some embodiments, disclosed herein are methods wherein iteratively refining the interference model comprises updating the interference estimate using the first transfer function and the second transfer function.

[0018] Disclosed herein are computer-implemented systems for removing EMI in measurement data. In some embodiments, the systems comprise: at least one computer processor; and one or more non-transitory computer-readable storage media storing instructions that, when executed by the at least one processor, cause the system to perform operations comprising: receiving measurement data from a primary sensor; receiving interference data from one or more auxiliary sensors; estimating an interference model based at least in part on the interference data from the auxiliary sensors; generating an interference estimate using the interference model and the auxiliary sensor data; iteratively refining the interference model using the interference estimate and the auxiliary sensor data; and generating interference-reduced measurement data based on the interference model.

[0019] In some embodiments, disclosed herein are systems wherein iteratively refining the interference model comprises computing one or more transfer functions for each auxiliary sensor, and updating the interference estimate based on the transfer functions.

[0020] In some embodiments, disclosed herein are systems wherein iteratively refining the interference model comprises computing a first transfer function for each auxiliary sensor based on inference data from each auxiliary sensor to produce a first interference estimate; and computing a second transfer function for each auxiliary sensor based on a previously estimated interference estimate.

[0021] In some embodiments, disclosed herein are systems wherein iteratively refining the interference model comprises updating the interference estimate using the first transfer function and the second transfer function.

[0022] Another aspect of the present disclosure provides a system comprising one or more computer processors and computer memory coupled thereto. The computer memory comprisesAttorney Docket No. 59984-716601machine executable code that, upon execution by the one or more computer processors, implements any of the methods above or elsewhere herein.

[0023] Additional aspects and advantages of the present disclosure will become readily apparent to those skilled in this art from the following detailed description, wherein only illustrative embodiments of the present disclosure are shown and described. As will be realized, the present disclosure is capable of other and different embodiments, and its several details are capable of modifications in various obvious respects, all without departing from the disclosure.Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive.BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The novel features of the disclosure are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present disclosure will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the disclosure are utilized, and the accompanying drawings (also “Figure” and “FIG.” herein), of which:

[0025] FIG. 1 illustrates an exemplified phantom image comparison of denoising performance between EDITER and a method for mitigating EMI (proposed algorithm), in accordance with example embodiments described herein.

[0026] FIG. 2 illustrates an exemplified human image comparison of denoising performance between EDITER and a method for mitigating EMI, in accordance with example embodiments described herein.

[0027] FIG. 3 illustrates an exemplified human image comparison of denoising performance between EDITER and a method for mitigating EMI, wherein EMI-Contaminated images were scanned directly from a primary coil, in accordance with example embodiments described herein.

[0028] FIG. 4 illustrates an additional exemplified human image comparison of denoising performance between EDITER and a method for mitigating EMI, wherein EMI-Contaminated images were scanned directly from the primary coil, in accordance with example embodiments described herein.

[0029] FIG. 5 illustrates an additional exemplified human image comparison of denoising performance between EDITER and the method for mitigating EMI, wherein EMI-Contaminated images were scanned directly from the primary coil, in accordance with example embodiments described herein.Attorney Docket No. 59984-716601

[0030] FIG. 6 shows a computer system that is programmed or otherwise configured to implement methods provided herein in accordance with example embodiments described herein.

[0031] FIG. 7A depicts components of an MRI scanning system including a dome-shaped housing for a magnetic array, the dome-shaped housing surrounding a region of interest therein and further depicting the dome-shaped housing positioned to receive at least a portion of the head of a patient reclined on the table into the region of interest, in accordance with example embodiments described herein.

[0032] FIG. 7B depicts a patient’s head positioned in the region of interest of the MRI scanning system of FIG. 7A, in accordance with example embodiments described herein.

[0033] FIG. 8 is a perspective view of an alternative dome-shaped housing for a magnetic array for use with the MRI scanning system of FIG. 7A, wherein access apertures are defined in the dome-shaped housing, in accordance with example embodiments described herein.

[0034] FIG. 9 is a perspective view of an alternative dome-shaped housing for a magnetic array for use with the MRI scanning system of FIG. 7A, wherein access apertures and an adjustable gap is defined in the dome-shaped housing, in accordance with example embodiments described herein.

[0035] FIG. 10 depicts a dome-shaped housing for use with an MRI scanning system having an access aperture in the form of a centrally-defined hole, in accordance with example embodiments described herein.

[0036] FIG. 11 is a cross-sectional view of the dome-shaped housing of FIG. 10, in accordance with example embodiments described herein.DETAILED DESCRIPTIONElectromagnetic Interference (EMI) Removal

[0037] Background noise can be prevalent with existing techniques for noise reduction on measurement data, degrading image quality and diagnostic usefulness. External Dynamic Interference Estimation and Removal (EDITER) is an existing EMI cancellation technique that can calculate impulse response functions dynamically which can map the data from multiple EMI detectors to the time varying artifacts, then remove the transformed detected EMI from the MR data. However, residue EMI may still be prevalent in images using EDITER. Thus, a more robust method for removing EMI in the measurement domain is needed for shielding-free MRI scanners. This disclosure addresses failures of noise reduction on measurement data by introducing methods of removing electromagnetic interference (EMI). Described herein, in certain embodiments, are systems and methods to remove EMI noise in the measurement domain. In certain embodiments, the method may comprise raw measurement data from theAttorney Docket No. 59984-716601primary coil XoE CN×N, the EMI in the primary coil fj' E CN×Nand the desired EMI free measurement data Xo' E CN×N[ncertain embodiments, a linear relationship Xo' = j' + Xo is assumed. In certain embodiments, there may be an assumption of a total of Ncexternal detectors to scan the noise surround the primary coil, where the noise signal from each coil may be denoted as {x, i = 1 ••• Nc. In some embodiments, external noise coils may be used to remove the noise and obtain XQ = Xo— j]'; however,may be unknown, therefore the method may comprise generating a characterization matrix to represent fj' by extracting the information of Ncnoise coils. In some embodiments, the noise characterization matrix may be denoted as E that coming from a convolution operation from [x, i = 1 ••• Nc. In some embodiments, there may exist an impulse response vector y such that: fj' = G * y. In some embodiments, y may be calculated by using scanned primary coil k-space data S: y = GTX0; then XQ may be approximated as Xo~ Xo— y = Xo— GTX0this approximation may be based on an observation that the EMI noise is too strong in the primary coil and Xo« fj '. In some embodiments, the approximation may not work when the primary coil noise weaker than the real signal of the scanned object. In some embodiments, the noised removed measurement date may be demonstrated as a final output X Q ’.

[0038] In some embodiments, the method may be used when T2weighted or fluid-attenuated inversion recovery (FLAIR) imaging contrasts are used. In some implementations, the method may comprise inputting a primary coil and noise coils k-space measurement data, wherein the measurement data may be described as Xt, i = 0, 1 ••• Ac; wherein at a time t, t = 1 ••• T. In some implementations, the method may comprise: constructing a convolution matrix E(t)from noise coils {X⃗i(t)}, i = 1 ••• Nccomputing transfer functions for each coil y^ «- Gj(t)X wherein each coil each coil can be represented by i = 0 ••• Ncestimating EMI signal in each coil fj^ «- G^y^\ wherein each coil each coil can be represented by i = 0 ••• Nc. In some implementations, this process is repeated: solve the transfer function for each coil by using the updated fj^: y'^ «- G^fj^ and estimate EMI signal in each coil fj'^ «- G^y'^- >(t) Mdetermining EMI mitigated signal in each coil X'i «- Xj — fj', wherein each coil each coil can be represented by i = 0 ••• Ac; concatenating each noise coils as multi-channel data {X^}^; applying an anisotropic diffusion algorithm on an EMI mitigated signal X'^for the primary coil. The EMI mitigated signal may comprise a real part and an imaginary part. In certain embodiments, is a method may comprise applying a curvature anisotropic diffusion (CAD) algorithm. In some implementations, a curvature anisotropic diffusion algorithm may beAttorney Docket No. 59984-716601applied separately to the real and imaginary parts of the EMI mitigated signal. In some implementations, the Curvature Anisotropic Diffusion (CAD) algorithm is a method for noise reduction that emphasizes preserving the structural integrity of the image, such as edges and detailed textures, by diffusing primarily along the curvature of level lines; choosing appropriate contrast parameter that determines sensitivity to edges, time steps, and number of iterations values can be critical for achieving desired noise reduction and edge preservation. In some implementations, the CAD algorithm is written in following equation:+= x^ +Δτ(∇(c(|∇x0(t)|) ∇x0(t)) + k(|∇x0(t)|)|∇x0(t)|). In some implementations, AT determines the increment in diffusion time for each iteration. In some embodiments, the diffusivity function c(|∇x0(t)|) can modulate the diffusion process based on the gradient magnitude of the image. In some embodiments, the curvature term k(|∇x0(t)|) can measure the curvature of the level sets of the image, which can help in preserving edges by promoting diffusion along directions of lower curvature.

[0039] In some implementations, the method may include resetting a primary coil and outputting an updated noise reduced primary coil k-space data X „ ’. In some embodiments, the CAD algorithm may be configured for reducing noise that may diffuse primarily along curvature of level lines, which may emphasize preserving structural integrity of an image. In an example, the structural integrity to be preserved may include edges and detailed textures.

[0040] In certain embodiments, is a method may comprise applying a gradient anisotropic diffusion (GAD) algorithm. In some embodiments, the GAD algorithm may include a partial differential equation that models flow of heat (i.e., diffusion) across an image, but may modify the flow based on a local gradient (e.g., edge information) of the image. In some embodiments, GAD can choose a diffusion coefficient to be spatially dependent based on local image gradients, ensuring selective smoothing. GAD algorithm is written in following equation:x0(t+1)= x0(t)+ λ∇(c(|x0(t)|) ∇x0(t)), where A is the time step size controlling the speed of diffusion. In some embodiments, function c takes the gradient magnitude to control the diffusion process.In some embodiments, when GAD may be used in image processing for noise reduction while preserving edges, GAD may be based on anisotropic diffusion. In some embodiments, conductance may be adjusted to be gradient-dependent. In some embodiments, the method may further comprise choosing an appropriate contrast parameter that can determine sensitivities to edges, times steps, number of iterations values, or some combination thereof. In some embodiments, the sensitivities to edges, times steps, number of iterations values, or someAttorney Docket No. 59984-716601combination thereof may be critical for achievement of a desired noise reduction and edge preservation.

[0041] FIG. 1 depicts an example comparison of denoising performance between an existing EMI mitigation technique (EDITER) and a method for mitigating EMI as described herein. The image generated using a method described herein demonstrated an improvement in signal-to-noise ratio (SNR) of 10.79 dB relative to the image produced using EDITER.

[0042] FIG. 2 illustrates an example comparison of denoising performance in a human image between EDITER and a method for mitigating EMI as described herein. The image generated using the described method demonstrated an improvement in SNR of approximately 3.01 dB relative to the image produced using EDITER.

[0043] FIG. 3 illustrates an example comparison of denoising performance in a human image between EDITER and a method for mitigating EMI as described herein, wherein EMI-contaminated images are acquired directly from a primary coil in accordance with example embodiments. The image generated using a method described herein demonstrated an improvement in SNR of approximately 2.28 dB relative to the image produced using EDITER.FIG. 4 illustrates an additional example comparison of denoising performance in a human image between EDITER and a method for mitigating EMI as described herein, wherein EMI-contaminated images were acquired directly from a primary coil. The image generated using a method described herein demonstrated an improvement in SNR of approximately 1.85 dB relative to the image produced using EDITER. FIG. 5 illustrates an additional example comparison of denoising performance in a human image between EDITER and a method for mitigating EMI as described herein, wherein EMI-contaminated images were acquired directly from a primary coil.

[0044] In some embodiments, the methods disclosed herein mitigate electromagnetic interference (EMI), resulting in an improvement in SNR of approximately 2.28 dB relative to an image produced using EDITER. In some embodiments, the improvement is from about 1 dB to about 12 dB. In some embodiments, the improvement is from about 1 dB to about 2 dB, from about 1 dB to about 3 dB, from about 1 dB to about 4 dB, from about 1 dB to about 5 dB, from about 1 dB to about 6 dB, from about 1 dB to about 7 dB, from about 1 dB to about 8 dB, from about 1 dB to about 9 dB, from about 1 dB to about 10 dB, from about 1 dB to about 11 dB, from about 1 dB to about 12 dB, from about 2 dB to about 3 dB, from about 2 dB to about 4 dB, from about 2 dB to about 5 dB, from about 2 dB to about 6 dB, from about 2 dB to about 7 dB, from about 2 dB to about 8 dB, from about 2 dB to about 9 dB, from about 2 dB to about 10 dB, from about 2 dB to about 11 dB, from about 2 dB to about 12 dB, from about 3 dB to about 4 dB, from about 3 dB to about 5 dB, from about 3 dB to about 6 dB, from about 3 dB to about 7Attorney Docket No. 59984-716601dB, from about 3 dB to about 8 dB, from about 3 dB to about 9 dB, from about 3 dB to about 10 dB, from about 3 dB to about 11 dB, from about 3 dB to about 12 dB, from about 4 dB to about 5 dB, from about 4 dB to about 6 dB, from about 4 dB to about 7 dB, from about 4 dB to about 8 dB, from about 4 dB to about 9 dB, from about 4 dB to about 10 dB, from about 4 dB to about 11 dB, from about 4 dB to about 12 dB, from about 5 dB to about 6 dB, from about 5 dB to about 7 dB, from about 5 dB to about 8 dB, from about 5 dB to about 9 dB, from about 5 dB to about 10 dB, from about 5 dB to about 11 dB, from about 5 dB to about 12 dB, from about 6 dB to about 7 dB, from about 6 dB to about 8 dB, from about 6 dB to about 9 dB, from about 6 dB to about 10 dB, from about 6 dB to about 11 dB, from about 6 dB to about 12 dB, from about 7 dB to about 8 dB, from about 7 dB to about 9 dB, from about 7 dB to about 10 dB, from about 7 dB to about 11 dB, from about 7 dB to about 12 dB, from about 8 dB to about 9 dB, from about 8 dB to about 10 dB, from about 8 dB to about 11 dB, from about 8 dB to about 12 dB, from about 9 dB to about 10 dB, from about 9 dB to about 11 dB, from about 9 dB to about 12 dB, from about 10 dB to about 11 dB, from about 10 dB to about 12 dB, or from about 11 dB to about 12 dB. In some embodiments, the improvement is from about 1 dB, about 2 dB, about 3 dB, about 4 dB, about 5 dB, about 6 dB, about 7 dB, about 8 dB, about 9 dB, about 10 dB, about 11 dB, or about 12 dB. In some embodiments, the improvement is at least about 1 dB, about 2 dB, about 3 dB, about 4 dB, about 5 dB, about 6 dB, about 7 dB, about 8 dB, about 9 dB, about 10 dB, or about 11 dB. In some embodiments, the improvement is at most about 2 dB, about 3 dB, about 4 dB, about 5 dB, about 6 dB, about 7 dB, about 8 dB, about 9 dB, about 10 dB, about 11 dB, or about 12 dB.MRI Scanning Systems

[0045] FIG. 7A depicts an MRI scanning system 700 that includes a dome-shaped housing 702 configured to receive a patient’s head. The dome-shaped housing 702 can further include at least one access aperture configured to allow access to the patient’s head to enable a neural intervention. A space within the dome-shaped housing 702 forms the region of interest for the MRI scanning system 700. Target tissue in the region of interest is subjected to magnetization fields / pulses, as further described herein, to obtain imaging data representative of the target tissue.

[0046] For example, referring to FIG. 7B, a patient can be positioned such that his / her head is positioned within the region of interest within the dome-shaped housing 702. The brain can be positioned entirely within the dome-shaped housing 702. In such instances, to facilitate intracranial interventions (e.g. neurosurgery) in concert with MR imaging, the dome-shaped housing 702 can include one or more apertures that provide access to the brain. Apertures can be spaced apart around the perimeter of the dome-shaped housing.Attorney Docket No. 59984-716601

[0047] The MRI scanning system 700 can include an auxiliary cart that houses certain conventional MRI electrical and electronic components, such as a computer, programmable logic controller, power distribution unit, and amplifiers, for example. The MRI scanning system 700 can also include a magnet cart that holds the dome-shaped housing 702, gradient coil(s), and / or a transmission coil, as further described herein. Additionally, the magnet cart can be attached to a receive coil in various instances. Referring primarily to FIG. 7A, the dome-shaped housing 702 can further include RF transmission coils, gradient coils 704 (depicted on the exterior thereof), and shim magnets 706 (depicted on the interior thereof). Alternative configurations for the gradient coil(s) 704 and / or shim magnets 706 are also contemplated. In various instances, the shim magnets 706 can be adjustably positioned in a shim tray within the dome-shaped housing 702, which can allow a technician to granularly configure the magnetic flux density of the dome-shaped housing 702.

[0048] Various structural housings for receiving the patient’s head and enabling neural interventions can be utilized with an MRI scanning system, such as the MRI scanning system 700. In one aspect, the MRI scanning system 700 may be outfitted with an alternative housing, such as a dome-shaped housing 802 (FIG. 8) or a two-part housing 902 (FIG. 9) configured to form a dome-shape. The dome-shaped housing 802 defines a plurality of access apertures 803; the two-part housing 902 also defines a plurality of access apertures 903 and further includes an adjustable gap 905 between the two parts of the housing.

[0049] In various instances, the housings 802 and 902 can include a bonding agent 908, such as an epoxy resin, for example, that holds a plurality of magnetic elements 910 in fixed positions. The plurality of magnetic elements 910 can be bonded to a structural housing 912, such as a plastic substrate, for example. In various aspects, the bonding agent 908 and structural housing 912 may be non-conductive or diamagnetic materials. Referring primarily to FIG. 9, the two-part housing 902 comprises two structural housings 912. In various aspect, a structural housing for receiving the patient’s head can be formed from more than two sub-parts. The access apertures 903 in the structural housing 912 provide a passage directly to the patient’s head and are not obstructed by the structural housing 912, bonding agent 908, or magnetic elements 910.The access apertures 903 can be positioned in an open space of the housing 902, for example.

[0050] There are many possible configurations of neural interventional MRI devices that can achieve improved access for surgical intervention. Many configurations build upon two main designs, commonly known as the Halbach cylinder and the Halbach dome.

[0051] In various instances, a dome-shaped housing for an MRI scanning system, such as the system 100, for example, can include a Halbach dome defining a dome shape and configured based on several factors including main magnetic field B0strength, field size, field homogeneity,Attorney Docket No. 59984-716601device size, device weight, and access to the patient for neural intervention. In various aspects, the Halbach dome comprises an exterior radius and interior radius at the base of the dome. The Halbach dome may comprise an elongated cylindrical portion that extends from the base of the dome. In one aspect, the elongated cylindrical portion comprises the same exterior radius and interior radius as the base of the dome and continues from the base of the dome at a predetermined length, at a constant radius. In another aspect, the elongated cylindrical portion comprises a different exterior radius and interior radius than the base of the dome (see e.g. FIGS. 8 and 9). In such instances, the different exterior radius and interior radius of the elongated cylindrical portion can merge with the base radii in a transitional region.

[0052] FIG. 10 illustrates an exemplary Halbach dome 1000 for an MRI scanning system, such as the system 700, for example, which defines an access aperture in the form of a hole or access aperture 1003, where the dome 1000 is configured to receive a head and brain B of the patient P within the region of interest therein, and the access aperture 1003 is configured to allow access to the patient P to enable neural intervention with a medical instrument and / or robotically-controlled surgical tool, in accordance with at least one aspect of the present disclosure. The Halbach dome 1000 can be built with a single access aperture 1003 at the top side 1018 of the dome 1000, which allows for access to the top of the skull while minimizing the impact to the magnetic field. Additionally or alternatively, the dome 900 can be configured with multiple access apertures around the structure 1016 of the dome 1000, as shown in FIGS. 8 and 9.

[0053] The diameter Dhole of the access aperture 1003 may be small (e.g. about 2.54 cm) or very large (substantially the exterior rextdiameter of the dome 1000). As the access aperture 1003 becomes larger, the dome 1000 begins to resemble a Halbach cylinder, for example. The access aperture 1003 is not limited to being at the apex of the dome 1000. The access aperture 1003 can be placed anywhere on the surface or structure 1016 of the dome 1000. In various instances, the entire dome 1000 can be rotated so that the access aperture 1003 can be co-located with a desired physical location on the patient P.

[0054] FIG. 17 depicts relative dimensions of the Halbach dome 1000, including a diameter Dholeof the access aperture 1003, a length L of the dome 1000, and an exterior radius rextand an interior radius rinof the dome 1000. The Halbach dome 1000 comprises a plurality of magnetic elements that are configured in a Halbach array and make up a magnetic assembly. The plurality of magnetic elements may be enclosed by the exterior radius rextand interior radius rinin the structure 1016 or housing thereof. In one aspect, example dimensions may be defined as: nn= 19.3 cm; rext = 23.6 cm; L = 38.7 cm; and 2.54 cm < D < 19.3 cm. In some embodiments, the rH1is from about 13 cm to about 14 cm, about 13 cm to about 15 cm, about 13 cm to about 16 cm, about 13 cm to about 17 cm, about 13 cm to about 18 cm, about 13 cm to about 19 cm, about 13Attorney Docket No. 59984-716601cm to about 20 cm, about 13 cm to about 21 cm, about 13 cm to about 22 cm, about 13 cm to about 23 cm, about 13 cm to about 24 cm, about 14 cm to about 15 cm, about 14 cm to about 16 cm, about 14 cm to about 17 cm, about 14 cm to about 18 cm, about 14 cm to about 19 cm, about 14 cm to about 20 cm, about 14 cm to about 21 cm, about 14 cm to about 22 cm, about 14 cm to about 23 cm, about 14 cm to about 24 cm, about 15 cm to about 16 cm, about 15 cm to about 17 cm, about 15 cm to about 18 cm, about 15 cm to about 19 cm, about 15 cm to about 20 cm, about 15 cm to about 21 cm, about 15 cm to about 22 cm, about 15 cm to about 23 cm, about 15 cm to about 24 cm, about 16 cm to about 17 cm, about 16 cm to about 18 cm, about 16 cm to about 19 cm, about 16 cm to about 20 cm, about 16 cm to about 21 cm, about 16 cm to about 22 cm, about 16 cm to about 23 cm, about 16 cm to about 24 cm, about 17 cm to about 18 cm, about 17 cm to about 19 cm, about 17 cm to about 20 cm, about 17 cm to about 21 cm, about 17 cm to about 22 cm, about 17 cm to about 23 cm, about 17 cm to about 24 cm, about 18 cm to about 19 cm, about 18 cm to about 20 cm, about 18 cm to about 21 cm, about 18 cm to about 22 cm, about 18 cm to about 23 cm, about 18 cm to about 24 cm, about 19 cm to about 20 cm, about 19 cm to about 21 cm, about 19 cm to about 22 cm, about 19 cm to about 23 cm, about 19 cm to about 24 cm, about 20 cm to about 21 cm, about 20 cm to about 22 cm, about 20 cm to about 23 cm, about 20 cm to about 24 cm, about 21 cm to about 22 cm, about 21 cm to about 23 cm, about 21 cm to about 24 cm, about 22 cm to about 23 cm, about 22 cm to about 24 cm, or about 23 cm to about 24 cm. In some embodiments, the rinis from about 13 cm, about 14 cm, about 15 cm, about 16 cm, about 17 cm, about 18 cm, about 19 cm, about 20 cm, about 21 cm, about 22 cm, about 23 cm, or about 24 cm. In some embodiments, the rinis from at least about 13 cm, about 14 cm, about 15 cm, about 16 cm, about 17 cm, about 18 cm, about 19 cm, about 20 cm, about 21 cm, about 22 cm, or about 23 cm. In some embodiments, the rinis from at most about 14 cm, about 15 cm, about 16 cm, about 17 cm, about 18 cm, about 19 cm, about 20 cm, about 21 cm, about 22 cm, about 23 cm, or about 24 cm. In some embodiments, the rextis from about 19 cm to about 30 cm. In some embodiments, the rextis from about 19 cm to about 20 cm, about 19 cm to about 21 cm, about 19 cm to about 22 cm, about 19 cm to about 23 cm, about 19 cm to about 24 cm, about 19 cm to about 25 cm, about 19 cm to about 26 cm, about 19 cm to about 27 cm, about 19 cm to about 28 cm, about 19 cm to about 29 cm, about 19 cm to about 30 cm, about 20 cm to about 21 cm, about 20 cm to about 22 cm, about 20 cm to about 23 cm, about 20 cm to about 24 cm, about 20 cm to about 25 cm, about 20 cm to about 26 cm, about 20 cm to about 27 cm, about 20 cm to about 28 cm, about 20 cm to about 29 cm, about 20 cm to about 30 cm, about 21 cm to about 22 cm, about 21 cm to about 23 cm, about 21 cm to about 24 cm, about 21 cm to about 25 cm, about 21 cm to about 26 cm, about 21 cm to about 27 cm, about 21 cm to about 28 cm, about 21 cm to about 29 cm, about 21 cm to about 30 cm,Attorney Docket No. 59984-716601about 22 cm to about 23 cm, about 22 cm to about 24 cm, about 22 cm to about 25 cm, about 22 cm to about 26 cm, about 22 cm to about 27 cm, about 22 cm to about 28 cm, about 22 cm to about 29 cm, about 22 cm to about 30 cm, about 23 cm to about 24 cm, about 23 cm to about 25 cm, about 23 cm to about 26 cm, about 23 cm to about 27 cm, about 23 cm to about 28 cm, about 23 cm to about 29 cm, about 23 cm to about 30 cm, about 24 cm to about 25 cm, about 24 cm to about 26 cm, about 24 cm to about 27 cm, about 24 cm to about 28 cm, about 24 cm to about 29 cm, about 24 cm to about 30 cm, about 25 cm to about 26 cm, about 25 cm to about 27 cm, about 25 cm to about 28 cm, about 25 cm to about 29 cm, about 25 cm to about 30 cm, about 26 cm to about 27 cm, about 26 cm to about 28 cm, about 26 cm to about 29 cm, about 26 cm to about 30 cm, about 27 cm to about 28 cm, about 27 cm to about 29 cm, about 27 cm to about 30 cm, about 28 cm to about 29 cm, about 28 cm to about 30 cm, or about 29 cm to about 30 cm. In some embodiments, the rextis from about 19 cm, about 20 cm, about 21 cm, about 22 cm, about 23 cm, about 24 cm, about 25 cm, about 26 cm, about 27 cm, about 28 cm, about 29 cm, or about 30 cm. In some embodiments, the rextis from at least about 19 cm, about 20 cm, about 21 cm, about 22 cm, about 23 cm, about 24 cm, about 25 cm, about 26 cm, about 27 cm, about 28 cm, or about 29 cm. In some embodiments, the rextis from at most about 20 cm, about 21 cm, about 22 cm, about 23 cm, about 24 cm, about 25 cm, about 26 cm, about 27 cm, about 28 cm, about 29 cm, or about 30 cm. In some embodiments, the L is from about 30 cm to about 52 cm. In some embodiments, the L is from about 30 cm to about 32 cm, about 30 cm to about 34 cm, about 30 cm to about 36 cm, about 30 cm to about 38 cm, about 30 cm to about 40 cm, about 30 cm to about 42 cm, about 30 cm to about 44 cm, about 30 cm to about 46 cm, about 30 cm to about 48 cm, about 30 cm to about 50 cm, about 30 cm to about 52 cm, about 32 cm to about 34 cm, about 32 cm to about 36 cm, about 32 cm to about 38 cm, about 32 cm to about 40 cm, about 32 cm to about 42 cm, about 32 cm to about 44 cm, about 32 cm to about 46 cm, about 32 cm to about 48 cm, about 32 cm to about 50 cm, about 32 cm to about 52 cm, about 34 cm to about 36 cm, about 34 cm to about 38 cm, about 34 cm to about 40 cm, about 34 cm to about 42 cm, about 34 cm to about 44 cm, about 34 cm to about 46 cm, about 34 cm to about 48 cm, about 34 cm to about 50 cm, about 34 cm to about 52 cm, about 36 cm to about 38 cm, about 36 cm to about 40 cm, about 36 cm to about 42 cm, about 36 cm to about 44 cm, about 36 cm to about 46 cm, about 36 cm to about 48 cm, about 36 cm to about 50 cm, about 36 cm to about 52 cm, about 38 cm to about 40 cm, about 38 cm to about 42 cm, about 38 cm to about 44 cm, about 38 cm to about 46 cm, about 38 cm to about 48 cm, about 38 cm to about 50 cm, about 38 cm to about 52 cm, about 40 cm to about 42 cm, about 40 cm to about 44 cm, about 40 cm to about 46 cm, about 40 cm to about 48 cm, about 40 cm to about 50 cm, about 40 cm to about 52 cm, about 42 cm to about 44 cm, about 42 cm to about 46 cm, about 42 cm to about 48Attorney Docket No. 59984-716601cm, about 42 cm to about 50 cm, about 42 cm to about 52 cm, about 44 cm to about 46 cm, about 44 cm to about 48 cm, about 44 cm to about 50 cm, about 44 cm to about 52 cm, about 46 cm to about 48 cm, about 46 cm to about 50 cm, about 46 cm to about 52 cm, about 48 cm to about 50 cm, about 48 cm to about 52 cm, or about 50 cm to about 52 cm. In some embodiments, the L is from about 30 cm, about 32 cm, about 34 cm, about 36 cm, about 38 cm, about 40 cm, about 42 cm, about 44 cm, about 46 cm, about 48 cm, about 50 cm, or about 52 cm. In some embodiments, the L is from at least about 30 cm, about 32 cm, about 34 cm, about 36 cm, about 38 cm, about 40 cm, about 42 cm, about 44 cm, about 46 cm, about 48 cm, or about 50 cm. In some embodiments, the L is from at most about 32 cm, about 34 cm, about 36 cm, about 38 cm, about 40 cm, about 42 cm, about 44 cm, about 46 cm, about 48 cm, about 50 cm, or about 52 cm. In some embodiments, the D is from about 2 cm to about 24 cm. In some embodiments, the D is from about 2 cm to about 4 cm, about 2 cm to about 6 cm, about 2 cm to about 8 cm, about 2 cm to about 10 cm, about 2 cm to about 12 cm, about 2 cm to about 14 cm, about 2 cm to about 16 cm, about 2 cm to about 18 cm, about 2 cm to about 20 cm, about 2 cm to about 22 cm, about 2 cm to about 24 cm, about 4 cm to about 6 cm, about 4 cm to about 8 cm, about 4 cm to about 10 cm, about 4 cm to about 12 cm, about 4 cm to about 14 cm, about 4 cm to about 16 cm, about 4 cm to about 18 cm, about 4 cm to about 20 cm, about 4 cm to about 22 cm, about 4 cm to about 24 cm, about 6 cm to about 8 cm, about 6 cm to about 10 cm, about 6 cm to about 12 cm, about 6 cm to about 14 cm, about 6 cm to about 16 cm, about 6 cm to about 18 cm, about 6 cm to about 20 cm, about 6 cm to about 22 cm, about 6 cm to about 24 cm, about 8 cm to about 10 cm, about 8 cm to about 12 cm, about 8 cm to about 14 cm, about 8 cm to about 16 cm, about 8 cm to about 18 cm, about 8 cm to about 20 cm, about 8 cm to about 22 cm, about 8 cm to about 24 cm, about 10 cm to about 12 cm, about 10 cm to about 14 cm, about 10 cm to about 16 cm, about 10 cm to about 18 cm, about 10 cm to about 20 cm, about 10 cm to about 22 cm, about 10 cm to about 24 cm, about 12 cm to about 14 cm, about 12 cm to about 16 cm, about 12 cm to about 18 cm, about 12 cm to about 20 cm, about 12 cm to about 22 cm, about 12 cm to about 24 cm, about 14 cm to about 16 cm, about 14 cm to about 18 cm, about 14 cm to about 20 cm, about 14 cm to about 22 cm, about 14 cm to about 24 cm, about 16 cm to about 18 cm, about 16 cm to about 20 cm, about 16 cm to about 22 cm, about 16 cm to about 24 cm, about 18 cm to about 20 cm, about 18 cm to about 22 cm, about 18 cm to about 24 cm, about 20 cm to about 22 cm, about 20 cm to about 24 cm, or about 22 cm to about 24 cm. In some embodiments, the D is from about 2 cm, about 4 cm, about 6 cm, about 8 cm, about 10 cm, about 12 cm, about 14 cm, about 16 cm, about 18 cm, about 20 cm, about 22 cm, or about 24 cm. In some embodiments, the D is from at least about 2 cm, about 4 cm, about 6 cm, about 8 cm, about 10 cm, about 12 cm, about 14 cm, about 16 cm, about 18 cm, about 20 cm, or aboutAttorney Docket No. 59984-71660122 cm. In some embodiments, the D is from at most about 4 cm, about 6 cm, about 8 cm, about 10 cm, about 12 cm, about 14 cm, about 16 cm, about 18 cm, about 20 cm, about 22 cm, or about 24 cm.

[0055] Based on the above example dimensions, a Halbach dome 1000 with an access aperture 1003 may be configured with a magnetic flux density Bo of around 72 mT, and an overall mass of around 35 kg. It will be appreciated that the dimensions may be selected based on particular applications to achieve a desired magnetic flux density Bo, total weight of the Halbach dome 1000 and / or magnet cart, and geometry of the neural intervention access aperture 1003.

[0056] In various aspects, the Halbach dome 1000 may be configured to define multiple access apertures 1003 placed around the structure 1016 of the dome 1000. These multiple access apertures 1003 may be configured to allow for access to the patient’s head and brain B using tools (e.g., surgical tools) and / or a surgical robot.

[0057] In various aspects, the access aperture 1003 may be adjustable. The adjustable configuration may provide the ability for the access aperture 1003 to be adjusted using either a motor, mechanical assist, or a hand powered system with a mechanical iris configuration, for example, to adjust the diameter Dhole of the access aperture 1003. This would allow for configuration of the dome without an access aperture 1003, conducting an imaging scan, and then adjusting the configuration of the dome 1000 and mechanical iris thereof to include the access aperture 1003 and, thus, to enable a surgical intervention therethrough.

[0058] Halbach domes and magnetic arrays thereof for facilitating neural interventions are further described in International Patent Application No. PCT / US2022 / 72143, titled NEURAL INTERVENTIONAL MAGNETIC RESONANCE IMAGING APPARATUS, filed May 5, 2022, which is incorporated by reference herein in its entirety.Computer Systems

[0059] The present disclosure provides computer systems that are programmed to implement methods of the disclosure. FIG. 6 shows a computer system 601 that is programmed or otherwise configured to reduce EMI noise in the measurement domain. The computer system 601 can regulate various aspects of noise reduction of the present disclosure, such as, for example, preservation of the structural integrity of the image or modification of the flow of heat based on edge information of the image. The computer system 601 can be an electronic device of a user or a computer system that is remotely located with respect to the electronic device. The electronic device can be a mobile electronic device.

[0060] The computer system 601 includes a central processing unit (CPU, also “processor” and “computer processor” herein) 605, which can be a single core or multi core processor, or a plurality of processors for parallel processing. The computer system 601 also includes memoryAttorney Docket No. 59984-716601or memory location 610 (e.g., random-access memory, read-only memory, flash memory), electronic storage unit 615 (e.g., hard disk), communication interface 620 (e.g., network adapter) for communicating with one or more other systems, and peripheral devices 625, such as cache, other memory, data storage and / or electronic display adapters. The memory 610, storage unit 615, interface 620 and peripheral devices 625 are in communication with the CPU 605 through a communication bus (solid lines), such as a motherboard. The storage unit 615 can be a data storage unit (or data repository) for storing data. The computer system 601 can be operatively coupled to a computer network (“network”) 630 with the aid of the communication interface 620. The network 630 can be the Internet, an internet and / or extranet, or an intranet and / or extranet that is in communication with the Internet. The network 630 in some cases is a telecommunication and / or data network. The network 630 can include one or more computer servers, which can enable distributed computing, such as cloud computing. The network 630, in some cases with the aid of the computer system 601, can implement a peer-to-peer network, which may enable devices coupled to the computer system 601 to behave as a client or a server.

[0061] The CPU 605 can execute a sequence of machine-readable instructions, which can be embodied in a program or software. The instructions may be stored in a memory location, such as the memory 610. The instructions can be directed to the CPU 605, which can subsequently program or otherwise configure the CPU 605 to implement methods of the present disclosure. Examples of operations performed by the CPU 605 can include fetch, decode, execute, and writeback.

[0062] The CPU 605 can be part of a circuit, such as an integrated circuit. One or more other components of the system 601 can be included in the circuit. In some cases, the circuit is an application specific integrated circuit (ASIC).

[0063] The storage unit 615 can store files, such as drivers, libraries and saved programs. The storage unit 615 can store user data, e.g., user preferences and user programs. The computer system 601 in some cases can include one or more additional data storage units that are external to the computer system 601, such as located on a remote server that is in communication with the computer system 601 through an intranet or the Internet.

[0064] The computer system 601 can communicate with one or more remote computer systems through the network 630. For instance, the computer system 601 can communicate with a remote computer system of a user (e.g., desktop PC). Examples of remote computer systems include personal computers (e.g., portable PC), slate or tablet PC’s (e.g., Apple® iPad, Samsung® Galaxy Tab), telephones, Smart phones (e.g., Apple® iPhone, Android-enabled device, Blackberry®), or personal digital assistants. The user can access the computer system 601 via the network 630.Attorney Docket No. 59984-716601

[0065] Methods as described herein can be implemented by way of machine (e.g., computer processor) executable code stored on an electronic storage location of the computer system 601, such as, for example, on the memory 610 or electronic storage unit 615. The machine executable or machine readable code can be provided in the form of software. During use, the code can be executed by the processor 605. In some cases, the code can be retrieved from the storage unit 615 and stored on the memory 610 for ready access by the processor 605. In some situations, the electronic storage unit 615 can be precluded, and machine-executable instructions are stored on memory 610.

[0066] The code can be pre-compiled and configured for use with a machine having a processer adapted to execute the code, or can be compiled during runtime. The code can be supplied in a programming language that can be selected to enable the code to execute in a pre-compiled or as-compiled fashion.

[0067] Aspects of the systems and methods provided herein, such as the computer system 601, can be embodied in programming. Various aspects of the technology may be thought of as “products” or “articles of manufacture” typically in the form of machine (or processor) executable code and / or associated data that is carried on or embodied in a type of machine readable medium. Machine-executable code can be stored on an electronic storage unit, such as memory (e.g., read-only memory, random-access memory, flash memory) or a hard disk.“Storage” type media can include any or all of the tangible memory of the computers, processors or the like, or associated modules thereof, such as various semiconductor memories, tape drives, disk drives and the like, which may provide non-transitory storage at any time for the software programming. All or portions of the software may at times be communicated through the Internet or various other telecommunication networks. Such communications, for example, may enable loading of the software from one computer or processor into another, for example, from a management server or host computer into the computer platform of an application server. Thus, another type of media that may bear the software elements includes optical, electrical and electromagnetic waves, such as used across physical interfaces between local devices, through wired and optical landline networks and over various air-links. The physical elements that carry such waves, such as wired or wireless links, optical links or the like, also may be considered as media bearing the software. As used herein, unless restricted to non-transitory, tangible “storage” media, terms such as computer or machine “readable medium” refer to any medium that participates in providing instructions to a processor for execution.

[0068] Hence, a machine readable medium, such as computer-executable code, may take many forms, including but not limited to, a tangible storage medium, a carrier wave medium or physical transmission medium. Non-volatile storage media include, for example, optical orAttorney Docket No. 59984-716601magnetic disks, such as any of the storage devices in any computer(s) or the like, such as may be used to implement the databases, etc. shown in the drawings. Volatile storage media include dynamic memory, such as main memory of such a computer platform. Tangible transmission media include coaxial cables; copper wire and fiber optics, including the wires that comprise a bus within a computer system. Carrier-wave transmission media may take the form of electric or electromagnetic signals, or acoustic or light waves such as those generated during radio frequency (RF) and infrared (IR) data communications. Common forms of computer-readable media therefore include for example: a floppy disk, a flexible disk, hard disk, magnetic tape, any other magnetic medium, a CD-ROM, DVD or DVD-ROM, any other optical medium, punch cards paper tape, any other physical storage medium with patterns of holes, a RAM, a ROM, a PROM and EPROM, a FLASH-EPROM, any other memory chip or cartridge, a carrier wave transporting data or instructions, cables or links transporting such a carrier wave, or any other medium from which a computer may read programming code and / or data. Many of these forms of computer readable media may be involved in carrying one or more sequences of one or more instructions to a processor for execution.

[0069] The computer system 601 can include or be in communication with an electronic display 635 that comprises a user interface (UI) 640 for providing, for example, -reduced images.Examples of UI's include, without limitation, a graphical user interface (GUI) and web-based user interface.

[0070] Methods and systems of the present disclosure can be implemented by way of one or more algorithms. An algorithm can be implemented by way of software upon execution by the central processing unit 605.Definitions

[0071] Unless defined otherwise, all terms of art, notations and other technical and scientific terms or terminology used herein are intended to have the same meaning as is commonly understood by one of ordinary skill in the art to which the claimed subject matter pertains. In some cases, terms with commonly understood meanings are defined herein for clarity and / or for ready reference, and the inclusion of such definitions herein should not necessarily be construed to represent a substantial difference over what is generally understood in the art.

[0072] Throughout this application, various embodiments may be presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the disclosure.Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosedAttorney Docket No. 59984-716601subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range.

[0073] The ranges disclosed herein also encompass any and all overlap, sub-ranges, and combinations thereof. Language such as “up to,” “at least,” “greater than,” “less than,” “between,” and the like includes the number recited. Numbers preceded by a term such as “approximately”, “about”, and “substantially” as used herein include the recited numbers, and also represent an amount close to the stated amount that still performs a desired function or achieves a desired result. The term “about” or “approximately” may mean within an acceptable error range for the particular value, which will depend in part on how the value is measured or determined, e.g., the limitations of the measurement system. For example, the terms “approximately”, “about”, and “substantially” may refer to an amount that is within less than 10% of, within less than 5% of, within less than 1% of, within less than 0.1% of, and within less than 0.01% of the stated amount. For example, “about” may mean within 1 or more than 1 standard deviation, per the practice in the art. Alternatively, “about” may mean a range of up to 20%, up to 10%, up to 5%, or up to 1% of a given value. As used herein, the term “about” a number refers to that number plus or minus 10% of that number. The term “about” a range refers to that range minus 10% of its lowest value and plus 10% of its greatest value. Where particular values are described in the application and claims, unless other-wise stated the term “about” meaning within an acceptable error range for the particular value may be assumed.

[0074] As used in the specification and claims, the singular forms “a”, “an” and “the” include plural references unless the context clearly dictates otherwise. For example, the term “a sample” includes a plurality of samples, including mixtures thereof.

[0075] Whenever the term “at least,” “greater than,” or “greater than or equal to” precedes the first numerical value in a series of two or more numerical values, the term “at least,” “greater than” or “greater than or equal to” applies to each of the numerical values in that series of numerical values. For example, greater than or equal to 1, 2, or 3 is equivalent to greater than or equal to 1, greater than or equal to 2, or greater than or equal to 3.

[0076] Whenever the term “no more than,” “less than,” or “less than or equal to” precedes the first numerical value in a series of two or more numerical values, the term “no more than,” “less than,” or “less than or equal to” applies to each of the numerical values in that series of numerical values. For example, less than or equal to 3, 2, or 1 is equivalent to less than or equal to 3, less than or equal to 2, or less than or equal to 1.

[0077] As used herein, the term "substantially" in reference to a given parameter, property, or condition means and includes to a degree that one of ordinary skill in the art would understandAttorney Docket No. 59984-716601that the given parameter, property, or condition is met with a degree of variance, such as within acceptable manufacturing tolerances. By way of example, depending on the particular parameter, proper-ty, or condition that is substantially met, the parameter, property, or condition may be at least 90.0% met, at least 95.0% met, at least 99.0% met, or even at least 99.9% met.

[0078] The terms “determining,” “measuring,” “evaluating,” “assessing,” “assaying,” and “analyzing” are often used interchangeably herein to refer to forms of measurement. The terms include determining if an element is present or not (for example, detection). These terms can include quantitative, qualitative or quantitative and qualitative determinations. Assessing can be relative or absolute. “Detecting the presence of’ can include determining the amount of something present in addition to determining whether it is present or absent depending on the context.

[0079] The terms “subject,” “individual,” or “patient” are often used interchangeably herein. A “subject” can be a biological entity containing expressed genetic materials. The subject can be a mammal. The mammal can be a human. The subject may be diagnosed or suspected of being at high risk for a disease. In some cases, the subject is not necessarily diagnosed or suspected of being at high risk for the disease.

[0080] The section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described.

[0081] While preferred embodiments of the present disclosure have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. It is not intended that the disclosure be limited by the specific examples provided within the specification. While the disclosure has been described with reference to the aforementioned specification, the descriptions and illustrations of the embodiments herein are not meant to be construed in a limiting sense. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the disclosure. Furthermore, it shall be understood that all aspects of the disclosure are not limited to the specific depictions, configurations or relative proportions set forth herein which depend upon a variety of conditions and variables. It should be understood that various alternatives to the embodiments of the disclosure described herein may be employed in practicing the disclosure. It is therefore contemplated that the disclosure shall also cover any such alternatives, modifications, variations, or equivalents. It is intended that the following claims define the scope of the disclosure and that methods and structures within the scope of these claims and their equivalents be covered thereby.

Claims

Attorney Docket No. 59984-716601CLAIMS WHAT IS CLAIMED IS:

1. A method of removing electromagnetic interference (EMI) in the measurement domain, the method comprising:detecting primary coil data and noise coil measurement data, wherein the measurement data is described as X^°\ i = 0, 1 ••• 1VC;wherein at a time t, t = 1 ••• T, the method further comprises:constructing a convolution matrix G^ from noise coils i = 1 ••• Nc,wherein at each coil i, i = 0 ••• Nc, the further steps comprise:computing transfer functions for each coil y^ = min 11G®y£— X^ 11, Yiwherein each coil is represented by i = 0 ••• Nc;estimating EMI signal in each coil<- G^y^\ wherein each coil is represented by i = 0 ••• Nc;computing transfer functions for each coil y^ = rnin 11 G^yt—11, Yiwherein each coil is represented by i = 0 ••• Nc;-^(t)estimating EMI signal in each coil J]'. <-}y,, wherein each coil is represented by i = 0 ••• Nc;(t) _^(t) determining EMI mitigated signal in each coil X'i <- Xt— j]', wherein each coil is represented by i = 0 ••• Nc;concatenating each noise coil as multi-channel data {X'-> (T) applying an anisotropic diffusion algorithm on an EMI mitigated signal X'Qfor the primary coil, wherein the EMI mitigated signal comprises a real part and an imaginary part, wherein the anisotropic diffusion algorithm is applied separately to the real and imaginary parts of the EMI mitigated signal;resetting the primary coil; andoutputting an updated noise reduced primary coil k-space data X „ ’.

2. The method of claim 1, wherein the anisotropic diffusion algorithm comprises a curvature anisotropic diffusion (CAD) algorithm.Attorney Docket No. 59984-7166013. The method of claim 1 or claim 2, wherein the anisotropic diffusion algorithm comprises a gradient anisotropic diffusion (GAD) algorithm.

4. The method of any one of claims 1-3, further comprising an outer loop, wherein the outer loop is run T times.

5. The method of claim 4, further comprising an inner iterative updating loop embedded inside the outer loop, wherein the inner iterative updating loop is run through all the noise coils from 0 to Nc.

6. The method of claim 5, wherein the transfer functions are solved for each noise coil, and each coil updates its own EMI mitigated data in the inner loop.

7. The method of claim any one of claims 1-6, wherein the transfer functions for each noise coil are computed two times.

8. The method of claim 7, wherein a first computation is based on original measurement data X^.

9. The method of claim 7 or claim 8, wherein a second computation is based on the updated EMI signal in each coil fj.

10. A computer-implemented system comprising: at least one computer processor, and one or more non-transitory computer-readable storage media storing instructions that, when executed by the at least one processor, cause the system to perform electromagnetic interference (EMI) removal operations comprising:detecting, from a primary coil, primary coil data and, from a plurality of noise coils, noise coil measurement data, wherein the measurement data is represented as x ° i = 0, 1 - Nc- for each time t, where t = 1 ••• T,constructing a convolution matrix G^ from the noise coil measurement data for each of the noise coils fx.^l, i = 1 ••• Ac;computing, for each noise coil, a first transfer function y^ = min 11 G^yt— X^ 11;Viestimating, for each noise coil, an EMI signal as f* «- G^y^;Attorney Docket No. 59984-716601computing, for each noise coil, a refined transfer function y^ = min 11 G^yi — |;Yiestimating, for each noise coil, a refined EMI signal as<- determining, for each noise coil, an EMI mitigated signal X'^ <-X^ — j]'®; concatenating the EMI mitigated signal from each noise coil as multi-channel data {xf’lSi;applying an anisotropic diffusion algorithm to an EMI mitigated primary coil signal X Q, wherein the EMI mitigated primary coil signal comprises a real part and an imaginary part, wherein the anisotropic diffusion algorithm is applied separately to the real and imaginary parts; andoutputting an updated noise reduced primary coil k-space data X „ ’.

11. The system of claim 10, wherein the anisotropic diffusion algorithm comprises a curvature anisotropic diffusion (CAD) algorithm.

12. The system of claim 10 or claim 11, wherein the anisotropic diffusion algorithm comprises a gradient anisotropic diffusion (GAD) algorithm.

13. The system of claim 10, wherein the EMI removal operations are performed in an outer loop, wherein the outer loop is run T times.

14. The system of claim 13, wherein the EMI removal operations further comprise an inner iterative updating loop embedded inside the outer loop, wherein the inner iterative updating loop runs through each of the noise coils from 0 to Nc.

15. The system of claim 14, wherein the transfer functions are solved for each noise coil, and each coil updates its own EMI mitigated data in the inner loop.

16. The system of any one of claims 10-15, wherein the EMI removal operations further comprise computing a transfer function for each noise coil two times.

17. The system of claim 16, wherein a first computation of a transfer function for each noise coil is based on original measurement data X^\Attorney Docket No. 59984-71660118. The system of claim 16 or claim 17, wherein a second computation of a transfer function for each noise coil is bed on the updated EMI signal in each coil.

19. A computer-implemented method for removing EMI in measurement data, the method comprising:receiving measurement data from a primary sensor;receiving interference data from one or more auxiliary sensors;estimating an interference model based at least in part on the interference data from the auxiliary sensors;generating an interference estimate using the interference model and the auxiliary sensor data;iteratively refining the interference model using the interference estimate and the auxiliary sensor data; andgenerating interference-reduced measurement data based on the refined interference model.

20. The method of claim 19, wherein iteratively refining the interference model comprises computing one or more transfer functions for each auxiliary sensor, and updating the interference estimate based on the transfer functions.

21. The method of claim 19 or claim 20, wherein iteratively refining the interference model comprises computing a first transfer function for each auxiliary sensor based on inference data from each auxiliary sensor to produce a first interference estimate; and computing a second transfer function for each auxiliary sensor based on a previously estimated interference estimate.

22. The method of claim 21, wherein iteratively refining the interference model comprises updating the interference estimate using the first transfer function and the second transfer function.

23. A computer-implemented system for removing EMI in measurement data, the system comprising:at least one computer processor; andone or more non-transitory computer-readable storage media storing instructions that, when executed by the at least one processor, cause the system to perform operations comprising:receiving measurement data from a primary sensor;Attorney Docket No. 59984-716601receiving interference data from one or more auxiliary sensors;estimating an interference model based at least in part on the interference data from the auxiliary sensors;generating an interference estimate using the interference model and the auxiliary sensor data;iteratively refining the interference model using the interference estimate and the auxiliary sensor data; andgenerating interference-reduced measurement data based on the interference model.

24. The system of claim 23, wherein iteratively refining the interference model comprises computing one or more transfer functions for each auxiliary sensor, and updating the interference estimate based on the transfer functions.

25. The system of claim 23 or 24, wherein iteratively refining the interference model comprises computing a first transfer function for each auxiliary sensor based on inference data from each auxiliary sensor to produce a first interference estimate; and computing a second transfer function for each auxiliary sensor based on a previously estimated interference estimate.

26. The system of claim 25, wherein iteratively refining the interference model comprises updating the interference estimate using the first transfer function and the second transfer function.

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