Systems and methods for real-time needle verification and localization

Abstract

Systems and methods for three-dimensional localization of an interventional device within a magnetic resonance imaging (MRI) system are disclosed. The method includes acquiring a baseline MR signal dataset of a target region and a subsequent dataset of the region following introduction of the interventional device using a hybrid encoding pulse sequence. The hybrid sequence applies spatiotemporal encoding in a first plane and Fourier encoding along an orthogonal axis to acquire highly undersampled projection data. A difference dataset is generated by mathematically evaluating the subsequent dataset against the baseline. A processing module determines the precise 3D spatial location of the interventional device by analyzing localized signal anomalies within the difference dataset. The approach circumvents fully sampled Cartesian k-space acquisitions, enabling rapid, intra-procedural tracking of magnetic and non-magnetic devices for manual or robotic guidance across diverse MRI environments, including, but not limited to, open, low-field, and single-sided systems.

Description

WSGR Docket No. 49880-720601SYSTEMS AND METHODS FOR REAL-TIMENEEDLE VERIFICATION AND LOCALIZATION CROSS-REFERENCE

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 779,702, filed March 28, 2025, which application is incorporated herein by reference.BACKGROUND OF THE INVENTION

[0002] Magnetic resonance imaging (MRI) is the gold standard for soft-tissue visualization, but tracking interventional devices during intra-procedural guidance remains a significant technical challenge. This difficulty is exacerbated in low-field, single-sided, and portable MRI architectures, wherein inherent static magnetic field inhomogeneities often degrade conventional fast-imaging sequences. Passive tracking methods are inadequate for rapid intra-procedural guidance because they rely on inherently slow, densely sampled k-space acquisitions or depend on pronounced magnetic susceptibility artifacts.

[0003] Minimally invasive interventional procedures, such as core needle biopsies, localized tumor ablations, and targeted drug delivery, require highly accurate spatial guidance to ensure the interventional device reaches the target anatomy without damaging adjacent critical structures. While modalities such as X-ray fluoroscopy and computed tomography (CT) offer fast acquisition times, they expose both the patient and the clinician to hazardous ionizing radiation and generally suffer from poor soft-tissue contrast.SUMMARY OF THE INVENTION

[0004] Provided herein is a method for three-dimensional localization of an interventional device within a magnetic resonance imaging (MRI) system. The method can comprise acquiring a first magnetic resonance (MR) signal dataset of a target region using a hybrid encoding pulse sequence. In some cases, the hybrid encoding pulse sequence applies spatiotemporal encoding to resolve spatial positions within a first plane and applies Fourier encoding to resolve spatial positions along an axis substantially orthogonal to the first plane. The method can comprise acquiring a second MR signal dataset of the target region using the hybrid encoding pulse sequence subsequent to an introduction of the interventional device. The method can comprise generating a difference dataset by subtracting the first MR signal dataset from the second MR signal dataset. The method can comprise determining a three-dimensional spatial location of the interventional device within the target region based at least in part on the generated difference dataset.WSGR Docket No. 49880-720601

[0005] In some cases, the interventional device comprises a dedicated interventional receive coil, and wherein acquiring the first MR signal dataset comprises mathematically initializing a null reference state corresponding to an absence of background anatomical signal, such that the generated difference dataset isolates an active localized signal acquired by the dedicated interventional receive coil during the acquisition of the second MR signal dataset. In some cases, the spatiotemporal encoding applied in the first plane comprises a cross-term spatiotemporal encoding (xSPEN) sequence, and wherein acquiring the first and second MR signal datasets comprises dynamically modulating magnetic field gradients to acquire a plurality of intersecting readout trajectories.

[0006] In some cases, determining the three-dimensional spatial location comprises performing a one-dimensional signal processing analysis directly on the plurality of intersecting readout trajectories prior to image reconstruction, identifying a localized signal anomaly along each respective readout trajectory, and calculating a multi-dimensional crossing point of the identified signal anomalies. The method can further comprise calculating a Full-Width at Half-Maximum (FWHM) of the localized signal anomaly and validating the localized signal anomaly if the FWHM corresponds to a known physical dimension of the interventional device. In some cases, determining the three-dimensional spatial location comprises mathematically reconstructing the generated difference dataset into a multi-dimensional spatial image and applying a spatial transformation or a second-order derivative analysis to the multi-dimensional spatial image to isolate a linear trajectory of the interventional device. In some cases, applying the second-order derivative analysis comprises computing a Hessian matrix across the multi-dimensional spatial image and isolating voxels satisfying an eigenvalue condition corresponding to a rigid tubular geometric structure. The method can further comprise applying mathematical erosion and dilation operations to the multi-dimensional spatial image to isolate contiguous voxel clusters conforming to a known cylindrical morphology of the interventional device. In some cases, determining the three-dimensional spatial location comprises applying an iterative reconstruction algorithm to the generated difference dataset, the iterative reconstruction algorithm minimizing an objective function that enforces a sparsity constraint to penalize background artifacts.

[0007] The method can further comprise iteratively repeating the acquiring, generating, and determining steps to continuously track dynamic movement of the interventional device. The method can further comprise calculating a predicted trajectory of the interventional device based on a velocity derived from the continuously tracked dynamic movement. The method can further comprise comparing the determined three-dimensional spatial location against the predicted trajectory and automatically triggering a cyber-physical safety intervention if a spatial deviationWSGR Docket No. 49880-720601exceeds a predefined threshold. The method can further comprise receiving extrinsic spatial data from an external tracking module or an interventional robot, and utilizing the extrinsic spatial data to generate a weighted probability map that biases the determination of the three-dimensional spatial location. The method can further comprise outputting a visual representation of the determined three-dimensional spatial location to a display device. In some cases, the visual representation comprises a subtraction image, a probabilistic heatmap, or a trajectory line plot.

[0008] In some cases, determining the three-dimensional spatial location comprises processing the generated difference dataset through an artificial neural network trained on a historical dataset of hybrid-encoded MR signals. In some cases, the artificial neural network comprises a convolutional neural network configured to output a voxel-wise probability mask that segments a structural void of the interventional device from background anatomical noise. In some cases, the artificial neural network is configured as an end-to-end regressor that receives un-reconstructed one-dimensional readout trajectories as input and directly outputs the three-dimensional spatial location of the interventional device. In some cases, the artificial neural network is trained utilizing a physics-informed loss function configured to mathematically penalize spatial predictions that violate a physical limitation model of the interventional device. In some cases, the MRI system is a single-sided MRI system comprising an intrinsic, permanent magnetic field gradient extending along the axis substantially orthogonal to the first plane.

[0009] In some cases, the MRI system comprises: a housing comprising a surface for contact with a subject; and a radio frequency receive (RF RX) coil network. In some cases, the RF RX coil network is configured to enable imaging in a region of interest. In some cases, the region of interest is external to the surface of the housing by a distance ranging from about 80 mm to about 120 mm.

[0010] In some cases, the RF RX coil network is configured to fully cover the surface such that there is no access aperture on the surface nearest the region of interest. In some cases, the RF RX coil network is configured for imaging external to the surface by a distance of about 100 mm.

[0011] In some cases, the RF RX coil network comprises a plurality of RF RX coils. In some cases, the RF RX coil network comprises a plurality of interconnected RF RX coils. In some cases, the RF RX coil network comprises a plurality of coupled RF RX coils. In some cases, a number of turns and loops of the RF RX coil is configured to be adjustable to cover an entire space between legs of the subject such that the region of interest is entirely or partially covered. In some cases, the housing further comprises a radio frequency transmit (RF TX) coil proximateWSGR Docket No. 49880-720601to the surface of the housing, wherein the RF TX coil is configured to generate an electromagnetic field in the region of interest.

[0012] In some cases, the RF TX coil comprises a plurality of figure-8 coils arranged proximal to the surface. In some cases, the plurality of figure-8 coils are configured to generate a varying magnetic RF field within the region of interest. In some cases, the plurality of figure-8 coils are orthogonal to each other. In some cases, the plurality of figure-8 coils are tunable to the same radiofrequency (RF) resonant frequencies. In some cases, the plurality of figure-8 coils are tunable to different RF resonant frequencies. In some cases, the plurality of figure-8 coils are configured to generate a uniform magnetic RF field within the region of interest.

[0013] The method can further comprise an electromagnet configured to generate an electromagnetic field in the region of interest. In some cases, the housing further comprises a gradient coil set positioned proximate to the surface, wherein the gradient coil set is configured to generate an electromagnetic field in the region of interest. In some cases, the gradient coil set comprises a single-sided gradient coil set.

[0014] In some cases, the MRI system is configured to be used for one or more of diagnosis, grading, treatment planning, or monitoring of pelvic conditions. In some cases, the MRI system comprises a magnetic field strength of less than about 0.5 T. In some cases, the MRI system comprises one or more of an open or single-sided MRI. In some cases, the housing comprises a through-bore access aperture. In some cases, the housing does not comprise a through-bore access aperture.

[0015] In some cases, the MRI system is configured to be used in an office setting without shielding or floor reinforcements. In some cases, the MRI system comprises at least one permanent magnet configured for use without superconducting material.

[0016] In some cases, the RF RX coil is configured to capture images of the subject when the subject is in a position in front of or on top of the MRI, wherein the position is a high lithotomy, an inclined lithotomy, or a seated position over the MRI. In some cases, the RF RX coil is configured to capture images of the subject when the subject is in contact with the surface of the MRI in the high lithotomy, the inclined lithotomy, or the seated position.

[0017] In some cases, the housing is configured to be positioned such that a central axis thereof is perpendicular to a floor when capturing images of the subject in the high lithotomy or the inclined lithotomy. In some cases, the housing is configured to be positioned such that a central axis thereof is parallel to a floor when capturing images of the subject in the seated position.

[0018] In some cases, the MRI system is configured to be usable in a first mode and a second mode, wherein the first mode comprises capturing images of the subject in the high lithotomy orWSGR Docket No. 49880-720601the inclined lithotomy when the housing is positioned such that a central axis thereof is perpendicular to a floor, and wherein the second mode comprises capturing images of the subject in the seated position when the housing is positioned such that a central axis thereof is parallel to the floor.

[0019] Disclosed herein is a system for three-dimensional localization of an interventional device. The system can comprise a magnetic resonance imaging (MRI) system. The system can comprise one or more processors. The system can comprise one or more non-transitory computer-readable storage media storing instructions that, when executed by the at least one processor, cause the system to: acquire, via the MRI system, a first magnetic resonance (MR) signal dataset of a target region using a hybrid encoding pulse sequence, wherein the hybrid encoding pulse sequence is configured to apply spatiotemporal encoding to resolve spatial positions within a first plane and is configured to apply Fourier encoding to resolve spatial positions along an axis substantially orthogonal to the first plane; acquire, via the MRI system, a second MR signal dataset of the target region using the hybrid encoding pulse sequence subsequent to an introduction of the interventional device; generate a difference dataset by subtracting the first MR signal dataset from the second MR signal dataset; and determine a three-dimensional spatial location of the interventional device within the target region based at least in part on the generated difference dataset.

[0020] In some cases, the interventional device comprises a dedicated interventional receive coil, and wherein acquiring the first MR signal dataset comprises mathematically initializing a null reference state corresponding to an absence of background anatomical signal, such that the generated difference dataset isolates an active localized signal acquired by the dedicated interventional receive coil during the acquisition of the second MR signal dataset. In some cases, the spatiotemporal encoding applied in the first plane comprises a cross-term spatiotemporal encoding (xSPEN) sequence, and wherein acquiring the first and second MR signal datasets comprises dynamically modulating magnetic field gradients to acquire a plurality of intersecting readout trajectories.

[0021] In some cases, determining the three-dimensional spatial location comprises performing a one-dimensional signal processing analysis directly on the plurality of intersecting readout trajectories prior to image reconstruction, identifying a localized signal anomaly along each respective readout trajectory, and calculating a multi-dimensional crossing point of the identified signal anomalies. In some cases, the instructions are further configured to cause the system to calculate a Full-Width at Half-Maximum (FWHM) of the localized signal anomaly and validate the localized signal anomaly if the FWHM corresponds to a known physical dimension of theWSGR Docket No. 49880-720601interventional device. In some cases, determining the three-dimensional spatial location comprises mathematically reconstructing the generated difference dataset into a multidimensional spatial image and applying a spatial transformation or a second-order derivative analysis to the multi-dimensional spatial image to isolate a linear trajectory of the interventional device. In some cases, applying the second-order derivative analysis comprises computing a Hessian matrix across the multi-dimensional spatial image and isolating voxels satisfying an eigenvalue condition corresponding to a rigid tubular geometric structure.

[0022] In some cases, the instructions are further configured to cause the system to apply mathematical erosion and dilation operations to the multi-dimensional spatial image to isolate contiguous voxel clusters conforming to a known cylindrical morphology of the interventional device. In some cases, determining the three-dimensional spatial location comprises applying an iterative reconstruction algorithm to the generated difference dataset, the iterative reconstruction algorithm minimizing an objective function that enforces a sparsity constraint to penalize background artifacts. In some cases, the instructions are further configured to cause the system to iteratively repeat the acquiring, generating, and determining steps to continuously track dynamic movement of the interventional device. In some cases, the instructions are further configured to cause the system to calculate a predicted trajectory of the interventional device based on a velocity derived from the continuously tracked dynamic movement. In some cases, the instructions are further configured to cause the system to compare the determined three-dimensional spatial location against the predicted trajectory and automatically trigger a cyberphysical safety intervention if a spatial deviation exceeds a predefined threshold.

[0023] In some cases, the instructions are further configured to cause the system to receive extrinsic spatial data from an external tracking module or an interventional robot and utilize the extrinsic spatial data to generate a weighted probability map that biases the determination of the three-dimensional spatial location. In some cases, the instructions are further configured to cause the system to output a visual representation of the determined three-dimensional spatial location to a display device, wherein the visual representation comprises a subtraction image, a probabilistic heatmap, or a trajectory line plot.

[0024] In some cases, determining the three-dimensional spatial location comprises processing the generated difference dataset through an artificial neural network trained on a historical dataset of hybrid-encoded MR signals. In some cases, the artificial neural network comprises a convolutional neural network configured to output a voxel-wise probability mask that segments a structural void of the interventional device from background anatomical noise. In some cases, the artificial neural network is configured as an end-to-end regressor that receives un-reconstructedWSGR Docket No. 49880-720601one-dimensional readout trajectories as input and directly outputs the three-dimensional spatial location of the interventional device. In some cases, the artificial neural network is trained utilizing a physics-informed loss function configured to mathematically penalize spatial predictions that violate a physical limitation model of the interventional device.

[0025] In some cases, the MRI system is a single-sided MRI system comprising an intrinsic, permanent magnetic field gradient extending along the axis substantially orthogonal to the first plane.

[0026] Another aspect of the present disclosure provides a system comprising one or more computer processors and computer memory coupled thereto. The computer memory comprises machine executable code that, upon execution by the one or more computer processors, implements any of the methods above or elsewhere herein.

[0027] 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.INCORPORATION BY REFERENCE

[0028] All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference.BRIEF DESCRIPTION OF THE DRAWINGS

[0029] 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 of which:

[0030] FIG. 1 shows a perspective view of a non-limiting example of a female patient being imaged in a high lithotomy, in accordance with example embodiments described herein.

[0031] FIG. 2 shows a perspective view of a non-limiting example of a female patient being imaged in a seated position, in accordance with example embodiments described herein.WSGR Docket No. 49880-720601

[0032] FIG.3A shows a schematic illustration of a magnetic resonance imaging system, in example embodiments disclosed herein.

[0033] FIG.3B illustrates an exploded view of the magnetic resonance imaging system shown in FIG.3A in accordance with example embodiments described herein.

[0034] FIG.3C shows a schematic front view of the magnetic resonance imaging system shown in FIG.3A, in example embodiments disclosed herein.

[0035] FIG.3D shows a schematic side view of the magnetic resonance imaging system shown in FIG.3A, in example embodiments disclosed herein.

[0036] FIG. 4 shows a schematic view of an implementation of a magnetic imaging apparatus, according to various embodiments.

[0037] FIG. 5 shows a schematic view of an implementation of a magnetic imaging apparatus, according to various embodiments.

[0038] FIG. 6 shows a schematic front view of a magnetic resonance imaging system 500, according to various embodiments.

[0039] FIG. 7A shows an example schematic illustration of a radio frequency receive coil (RF-RX) array including individual coil elements, in example embodiments disclosed herein.

[0040] FIG. 7B shows an example illustration of a loop coil along with example calculations for a loop coil magnetic field, in example embodiments disclosed herein.

[0041] FIG. 7C shows an example X-Y chart illustrating the magnetic field as a function of radius of a loop coil, in example embodiments disclosed herein.

[0042] FIG. 7D shows a cross-sectional illustration of a portion of the human body, namely in the area of the prostate in accordance with example embodiments described herein.

[0043] FIG. 8 shows a flowchart for a method of performing magnetic resonance imaging, according to various embodiments.

[0044] FIG. 9 shows a flowchart for another method of performing magnetic resonance imaging, according to various embodiments.

[0045] FIG. 10 shows a flowchart for a method of performing a scan on a magnetic resonance imaging system, according to various embodiments.

[0046] FIG. 11 shows a flowchart for another method of performing a scan on a magnetic resonance imaging system, according to various embodiments.

[0047] FIGS. 12A-12X illustrate various positions of patient depending on the type of anatomical scan for imaging in a magnetic resonance imaging system, according to various embodiments.WSGR Docket No. 49880-720601

[0048] FIG. 13 shows a schematic view of figure-8 coils described herein disposed within the housing of an MRI system in accordance with example embodiments described herein.

[0049] FIG. 14 shows an example computer system that is programmed or otherwise configured to implement methods provided herein in accordance with example embodiments described herein.

[0050] FIG. 15 shows a schematic flow illustration depicting a signal processing pipeline for isolating and determining the spatial coordinates of an interventional device utilizing onedimensional difference datasets, in accordance with one or more embodiments.

[0051] FIG. 16 shows a flowchart illustrating a generalized method for the three-dimensional localization of an interventional device within a magnetic resonance imaging (MRI) system, in example embodiments disclosed herein.

[0052] FIG. 17 shows a block diagram illustrating a system architecture for the three-dimensional localization and robotic guidance of an interventional device within an MRI environment, in accordance with example embodiments described herein.

[0053] FIG. 18 shows an exemplary pulse sequence diagram illustrating the radial cross-term spatiotemporal encoding (xSPEN) portion of the sequence implemented utilizing a CPMG acquisition, in accordance with one or more embodiments described herein.

[0054] FIG. 19 shows a schematic illustration of an experimental physical setup for device verification and localization, featuring a homogeneous gel phantom positioned in front of a single-sided MRI magnet face with an interventional needle inserted along the longitudinal z-axis, in accordance with one or more embodiments.

[0055] FIGs. 20A-20B show exemplary plots and a table of temporal offsets and spatial distances depicting one-dimensional difference datasets generated from four radial readout trajectories (spokes) between a baseline state and a post-insertion state with the experimental setup depicted in FIG. 19, in accordance with one or more embodiments.

[0056] FIG. 21 shows an exemplary reconstructed, multi-dimensional spatial image of the target region overlaid with actual physical needle coordinates generated in phantom using the experimental setup depicted in FIG. 19, in accordance with one or more embodiments.

[0057] FIG. 22 shows an exemplary spatial coordinate map comparing the algorithmically predicted locations of the interventional device against the actual physical position of the interventional device generated in phantom using the experimental setup depicted in FIG. 19, in accordance with one or more embodiments.WSGR Docket No. 49880-720601DETAILED DESCRIPTION OF THE INVENTION

[0058] The present disclosure relates generally to magnetic resonance imaging (MRI) systems and methods, and more specifically to systems and methods for the real-time, three-dimensional localization and dynamic tracking of interventional devices utilizing magnetic resonance.

[0059] The fundamental physics of MRI data acquisition may present severe limitations for intra-procedural interventional guidance. MRI can rely on Fourier-based encoding, which necessitates the sequential, line-by-line filling of a complete multi-dimensional Cartesian k-space matrix (e.g., via discrete phase-encoding steps). This process can be inherently time-consuming, often requiring several minutes to acquire a single high-resolution 3D volume. In an interventional setting, where a physician or robotic system is actively advancing a needle into tissue, a multi-minute temporal lag may render the spatial image dangerously obsolete; by the time the volume is mathematically reconstructed, the physical interventional device has already moved.

[0060] Furthermore, at low magnetic field strengths, these susceptibility artifacts may be negligible or absent, rendering passive tracking ineffective, particularly when utilizing modem, non-magnetic interventional devices. To overcome these limitations, the disclosed method may utilize a hybrid encoding pulse sequence, which combines spatiotemporal encoding in a first plane with Fourier encoding along a substantially orthogonal axis, to acquire projection data before and after device insertion. This approach may dynamically isolate the localized signal anomalies corresponding to the device, such as signal void from tissue displacement or hyperintensity from active signal or positive contrast artifacts, without relying on dense 3D k-space matrices or requiring magnetic susceptibility blooming. By generating and analyzing a difference dataset between these sequential scans, the system can accurately localizes both magnetic and non-magnetic devices. This methodology can enable accurate spatial localization on the order of seconds, thereby facilitating precise manual or robotic guidance across diverse MRI environments.

[0061] To achieve actionable, intra-procedural temporal resolution (e.g., reducing scan times to the order of seconds rather than minutes), MRI tracking techniques can attempt to bypass fully sampled k-space acquisition by heavily relying on "passive" tracking. Passive tracking may attempt to locate an interventional device by observing the magnetic susceptibility artifact — a localized signal void or "dark spot" — created by the device's metallic structure distorting the local magnetic field (Bo).

[0062] However, passive tracking methodologies may suffer from two critical failure modalities. First, the susceptibility artifact can be notoriously difficult to parameterize; the signal void oftenWSGR Docket No. 49880-720601"blooms" to a size significantly larger than the physical device, making it mathematically impossible to determine the exact microscopic coordinate of the device tip. Second, and more restrictively, passive tracking can rely entirely on the metallurgical composition of the device. As the medical field shifts toward strictly non-magnetic, MRI-compatible interventional devices (e.g., high-grade titanium, polymer, or ceramic needles) to improve general patient safety, passive tracking can fail completely. Non-magnetic devices do not induce a massive susceptibility void, so they can be rendered effectively invisible in the highly undersampled, low-resolution fast scans utilized in the prior art.The Shift to Point-of-Care and Low-Field MRI

[0063] Furthermore, the physical landscape of interventional MRI may be rapidly shifting.While high-field, closed-bore MRI scanners (e.g., 1.5T or 3.0T) can offer high baseline spatial resolution, their enclosed cylindrical geometry severely restricts physician access to the patient during a procedure. Consequently, there can be an increasing clinical demand for open, singlesided, portable, and low-field MRI scanners that bring point-of-care imaging directly into the operating room. However, these specialized hardware architectures can present severe physicsbased tracking challenges. Low-field and single-sided systems can often feature intrinsically highly inhomogeneous magnetic fields and heavily restricted gradient strengths. In these environments, fast-imaging pulse sequences (such as Echo Planar Imaging or EPI) can suffer from catastrophic phase-accumulation artifacts, geometric distortion, and rapid signal decay, rendering standard real-time tracking entirely unusable.The Bottleneck in MRI-Guided Robotics

[0064] Simultaneously, the integration of interventional robotics into the MRI suite may present another compounding challenge. While a human physician may be able to visually interpolate the trajectory of a needle despite a blooming artifact or low frame rate, an autonomous or semi-autonomous interventional robot cannot. Interventional robotics can require continuous, ultra-low-latency data streams consisting of precise, mathematically rigid multidimensional coordinates (x, y, z). If the spatial tracking data suffers from temporal lag or geometric blooming, the robot's control algorithms cannot accurately execute dynamic safety protocols, which can severely increase the risk of procedural deviation or tissue damage.

[0065] Therefore, there is a persistent and recognized need for an MRI-based localization system that can circumvent the temporal bottlenecks of fully sampled Fourier k-space acquisition.Specifically, there is a need for an ultra-fast, highly accurate tracking methodology that canWSGR Docket No. 49880-720601resolve three-dimensional spatial coordinates in real-time, which can reliably localize both magnetic and non-magnetic interventional devices, and which remains exceptionally robust in the highly inhomogeneous environments of open, single-sided, and low-field MRI systems to facilitate robotic guidance.Hybrid 3D Projection Data Acquisition

[0066] In some embodiments encompassed by the present disclosure, the system executes a hybrid encoding pulse sequence to acquire three-dimensional projection data of a target region. In some embodiments, to overcome the limitations of purely Fourier-based or purely spatiotemporal-based 3D imaging, the hybrid encoding pulse sequence applies a spatiotemporal encoding scheme (e.g., cross-term spatiotemporal encoding, or xSPEN) to resolve spatial positions within a first plane (e.g., the transverse or x-y plane), while simultaneously or sequentially applying Fourier encoding (e.g., phase encoding or slice selection) to resolve spatial positions along an axis substantially orthogonal to the first plane (e.g., the longitudinal or z-axis).Generalized Mathematical Formulation

[0067] In some embodiments, by coupling these distinct encoding mechanisms, the hybrid pulse sequence mathematically isolates spatial coordinates without requiring a fully sampled 3D Cartesian k-space matrix. In some embodiments, the acquired three-dimensional signal S for a given temporal readout and spatial projection can be generalized by the following continuous signal equation:S(t, kz) = $ p(x, y, z)el^xSPENl-x'y't>elkzZdx dydzwherein:• p(x, y, z represents the net transverse magnetization or spin density of the target region at a given 3D coordinate;• xspEN^ i y> t) represents the spatiotemporal quadratic phase imparted by the cross-term gradients dynamically modulated in the first plane over readout time t; and• kzrepresents the Fourier spatial frequency encoding applied along the orthogonal longitudinal axis, which may be achieved via discrete phase-encoding steps or continuous slice-selection gradients.Radial Spatiotemporal Embodiment

[0068] In some embodiments utilizing non-Cartesian radial spatiotemporal encoding (e.g., acquiring radial spokes), the generalized spatiotemporal phase XSP N mathematically resolvesWSGR Docket No. 49880-720601into a highly localized spatial profile via the stationary phase approximation. In some embodiments, the resulting spatiotemporal signal contribution SXSPEN for a single readout trajectory at a given projection angle 0 can be explicitly expressed by the proportional relationship:SxSPEN(t, 0)KJ r p(r, 0)sinc[aB(r, 0) + t]drwherein:• (r, 0 indicates the spatial coordinates in a polar reference frame corresponding to the first plane;• r is the radial distance and dr is the integration variable along the projection axis;• p(r, 0 represents the net magnetic moment (spin density) along the projection trajectory;• B(r, 0 represents the magnetic field distribution at that position, encompassing both the applied magnetic field gradients and any intrinsic gradients of the MRI system; and• a is a system constant related to the bandwidth and sweep rate of the frequency-swept excitation and refocusing pulses (e.g., WURST pulses).

[0069] In some embodiments, this radial formulation demonstrates the core principle of the hybrid spatiotemporal encoding step: the sine function isolates a specific, narrow spatial location at any given temporal point t during the readout. In some embodiments, consequently, the temporal signal difference between consecutive scans maps directly to the spatial coordinates of the interventional device along that spoke, effectively resolving the localized signal void in all three spatial dimensions while bypassing the need for a Fourier transform in the transverse plane.Physical Data Acquisition and Undersampling

[0070] In some embodiments, to execute this mathematical framework physically, the data acquisition comprises acquiring a minimum of one readout trajectory along each encoded spatial direction. In some embodiments, utilizing non-Cartesian spatiotemporal encoding in the first plane, the magnetic field gradients are dynamically modulated to acquire a plurality of intersecting readout trajectories, such as rotating the gradients to acquire radial spokes. In some embodiments, because the hybrid encoding sequence relies on tracking specific sine-resolved spatial voids rather than filling a complete Cartesian grid, the projection data can be highly undersampled. In some embodiments, this extreme undersampling enables the ultra-fast or realtime temporal resolution strictly necessary for accurate interventional device tracking.Temporal Acquisition and Dynamic TrackingWSGR Docket No. 49880-720601

[0071] In some embodiments, to isolate the physical structure of the interventional device (e.g., a biopsy needle or focal treatment probe) from the background anatomical tissue, the system acquires at least two temporal datasets. In some embodiments, a first MR signal dataset is acquired prior to the insertion of the interventional device to establish a reference field. In some embodiments, a second MR signal dataset is acquired subsequent to the insertion of the device. In some embodiments for dynamic tracking, the system continuously acquires ongoing projection datasets at multiple sequential timepoints during the interventional procedure.

[0072] In some embodiments, utilizing an active interventional receiver coil (e.g., a dedicated microcoil embedded on the device) independent of the external standard coils, the background anatomical tissue does not generate a baseline signal within the coil's localized reception field prior to insertion. In some embodiments, the step of acquiring the first MR signal dataset (the baseline) comprises mathematically initializing a null reference state (e.g., generating a multidimensional array of zeros). In some embodiments, consequently, the step of generating the difference dataset comprises evaluating the subsequent post-insertion MR signal dataset against this null reference state, effectively utilizing the raw, highly localized active signal of the microcoil as the absolute difference.Signal Difference Calculation and Projection-Domain Processing

[0073] In some embodiments, upon acquiring the temporal datasets, the system calculates a signal difference (i.e., generating a subtraction map or dataset). In some embodiments, the system identifies the signal difference directly along the different projection axes prior to reconstructing the data into an image domain. In some embodiments, by subtracting the pairs of raw projection readouts (e.g., subtracting a baseline radial spoke from a subsequent radial spoke at the same angle), the background tissue signal is substantially nulled. In some embodiments, this leaves only a localized signal difference representing the signal void (hypointensity) or signal artifact (hyperintensity) induced by the interventional device along that specific projection axis.

[0074] In some embodiments, geometrically, each localized signal difference defines a line of potential spatial coordinates perpendicular to the projection angle. In some embodiments, the system calculates the exact multi-dimensional spatial coordinates of the device by identifying the geometric intersection (i.e., the crossing point) of these lines from two or more distinct projection angles. In some embodiments, for enhanced accuracy, the system may acquire additional spokes to generate a scatter plot or probabilistic heatmap of intersecting points, thereby isolating the precise location of the interventional device without requiring a full Cartesian image reconstruction.WSGR Docket No. 49880-720601Mathematical Image Reconstruction

[0075] In some embodiments, the system reconstructs the acquired projection data into a spatial image or a multi-dimensional heatmap. In some embodiments, this reconstruction may occur before the subtraction step (subtracting reconstructed image pairs) or after the subtraction step (directly reconstructing a difference image from the subtracted projections).

[0076] In some embodiments, the reconstruction module may utilize various mathematical transformations depending on the sampling density. In some embodiments, the system applies a Radon transform-based b ackprojection (e.g., filtered b ackprojection) to reconstruct the radial spatiotemporal projection data into a spatial map. In some embodiments, which may be suited for highly undersampled or non-Cartesian hybrid trajectories, the system utilizes a system matrix inversion to reconstruct the data.

[0077] In some embodiments, to maintain high spatial resolution during the highly undersampled dynamic tracking, the system may employ iterative reconstruction algorithms. In some embodiments, the iterative reconstruction applies a sparsity constraint (e.g., compressed sensing) to the difference dataset. In some embodiments, because the subtraction of the background anatomy renders the difference dataset inherently sparse (containing primarily the localized signal of the needle), LI -norm minimization or total variation (TV) penalties can be aggressively applied to rapidly converge on the exact three-dimensional coordinates of the interventional device without artifacts.

[0078] In some embodiments, to solve for the multi-dimensional spatial coordinates from the highly undersampled projection data, the processing module executes an iterative reconstruction algorithm that minimizes a cost function. In some embodiments, the objective function for reconstructing the difference image p can be expressed as:p = arg min | Ep — AS| \ + AI^Pp^pwherein:• E represents the forward encoding system matrix modeling the hybrid spatiotemporal and Fourier acquisition;• p represents the reconstructed image volume being optimized;• A represents the acquired difference dataset (the subtracted projection data); • | Ep — AS 12 enforces data consistency (the L2-norm) between the reconstructed image and the acquired difference data;• represents a sparsifying transform (e.g., spatial finite differences for Total Variation, or a wavelet transform); andWSGR Docket No. 49880-720601• X is a regularization parameter controlling the weight of the LI -norm sparsity penalty I^Ppli-

[0079] In some embodiments, because the background anatomy has been subtracted out of AS, the true signal of the needle is inherently sparse, allowing the algorithm to aggressively penalize artifacts and converge rapidly on the exact needle coordinates.Real-Time Trajectory and Velocity Tracking

[0080] In some embodiments, building upon the ultra-fast temporal resolution afforded by the highly undersampled hybrid projection acquisition, the system is configured to perform continuous dynamic tracking of the interventional device. In some embodiments, the steps of acquiring the MR signal dataset, generating the difference dataset, and determining the spatial location are performed iteratively in real-time. In some embodiments, as the interventional device (e.g., a biopsy needle) is advanced into the target region, the system calculates a sequence of three-dimensional spatial coordinates representing the dynamic position of the device tip.

[0081] In some embodiments, by analyzing the change in the three-dimensional spatial coordinates over the known temporal acquisition intervals, the system’s processing module calculates a dynamic velocity vector and a predicted trajectory of the interventional device. In some embodiments, to increase the accuracy of the predicted trajectory, the processing module may apply a physical limitation model of the interventional device. In some cases, the physical limitation model may include a maximum mechanical bending angle or a stiffness coefficient specific to a particular gauge of biopsy needle, mathematically constraining the predicted trajectory to physically possible insertion paths and filtering out anomalous coordinate data.Cyber-Physical Safety Systems and Threshold Monitoring

[0082] In some embodiments, the system utilizes the calculated dynamic tracking data to prevent tissue damage or procedural deviation. In some embodiments, the system is configured to continuously compare the real-time determined three-dimensional spatial location of the interventional device against a pre-planned procedural path or the predicted trajectory.

[0083] In some embodiments, if the deviation between the actual spatial location and the predicted trajectory exceeds a predefined spatial threshold (e.g., a deflection of greater than 2 millimeters), the system automatically triggers a cyber-physical safety intervention. In some embodiments, where the interventional device is manually inserted, the safety intervention may comprise outputting a real-time visual alert on a graphical user interface (GUI) or an audible alarm to the physician. In some embodiments, where the interventional device is driven by an interventional robot, the system transmits a hardware interrupt signal (i.e., a mechanical stopWSGR Docket No. 49880-720601flag) directly to the robot's control unit, automatically halting further insertion of the device to prevent off-target penetration.Intrinsic Signal Detection via External Coils

[0084] In some embodiments, with baseline tracking, the three-dimensional spatial location of the interventional device is determined purely through intrinsic signal detection. In some embodiments, the system utilizes standard external MR receiver coils to identify a hypointense signal (e.g., a signal void or localized signal drop) or a hyperintense signal (e.g., a susceptibility artifact) caused by the physical structure of the interventional device displacing or interacting with the background tissue protons.Localized Signal Detection via Dedicated Interventional Coils

[0085] In some embodiments, to overcome potential sensitivity limitations of standard external coils, or to maximize the processing speed of the projection crossing-point calculations, advanced embodiments utilize dedicated localized signal detection. In some embodiments, the data acquisition step comprises receiving localized MR signals via a dedicated receive coil physically coupled to, mounted on, or embedded within the interventional device (e.g., a microcoil integrated into the tip or shaft of a biopsy needle).

[0086] In some embodiments, including in low-field environments where external coils may lack sufficient sensitivity, or where minimizing computational overhead is prioritized for real-time tracking, the system may determine the spatial location of the interventional device relying exclusively on the localized MR signals acquired by the dedicated interventional coil. In some embodiments, because the dedicated microcoil possesses a highly restricted spatial sensitivity profile, it does not detect the broader anatomical background. In some embodiments, the system can bypass background tissue subtraction by mathematically utilizing a null reference array as the baseline dataset, directly mapping the active projection-domain peak of the microcoil to the spatial coordinate of the device tip. In some embodiments, the system's processing module can execute a sensor fusion algorithm that simultaneously acquires and processes data from both the dedicated interventional receive coil and the standard external MR receiver coils, crossreferencing the active microcoil peak with the passive subtraction void of the external coils to maximize spatial confidence.Integration of Extrinsic Tracking Modalities and Prior Data

[0087] In some embodiments, in addition to the internal MR signal data, the system may incorporate extrinsic spatial data to guide and weight the detection algorithms. In some embodiments, the hybrid encoding sequence relies on identifying the crossing point ofWSGR Docket No. 49880-720601intersecting projection trajectories, narrowing the spatial search area computationally accelerates the localization.

[0088] In some embodiments, the algorithmic analysis incorporates real-time auxiliary navigational data from an external tracking module, such as an infrared (IR) or optical tracking probe coupled to an extra-corporeal portion of the interventional device. In some embodiments, including automated or semi-automated configurations, the tracking module may receive extrinsic kinematic operation coordinates directly from an interventional robot driving the device.

[0089] In some embodiments, the processing module utilizes this extrinsic spatial data, along with prior anatomical imaging data (e.g., a previously acquired high-resolution T2-weighted static volume), to generate a weighted probability map. In some embodiments, by weighting the expected position of the needle based on the extrinsic tracker trajectory or the robotic coordinates, the system biases the spatiotemporal and Fourier hybrid reconstruction toward the expected spatial sector. In some embodiments, this extrinsic data fusion dramatically reduces the likelihood of false-positive crossing points in the projection data, ensuring robust localization.Data Preprocessing and Smoothing

[0090] In some embodiments, prior to executing the primary spatial analysis, the processing module may apply one or more preprocessing algorithms to the raw MR signal datasets, the individual readout trajectories, or the generated difference dataset to increase the signal -to-noise ratio (SNR). In some embodiments, because real-world low-field environments introduce thermal noise and transient artifacts, the system may apply smoothing filters (e.g., a Gaussian filter to suppress high-frequency noise, or a median filter to remove salt-and-pepper artifacts) configured to smooth the background data without substantially eroding the localized signal void of the interventional device. In some embodiments, additional preprocessing steps may include baseline signal correction, phase-unwrapping, or motion-compensation algorithms to align the temporal datasets prior to subtraction.

[0091] In some embodiments, following the generation and optional preprocessing of the difference dataset, the system executes an algorithmic analysis to isolate the exact spatial coordinates of the interventional device. In some embodiments, depending on processing speed requirements, the system may execute this analysis in the raw projection domain, the reconstructed image domain, or a combination thereof.WSGR Docket No. 49880-720601Projection-Domain Analysis (Minimal Data Embodiment)

[0092] In some embodiments, with highly undersampled, real-time tracking configurations, the system bypasses full image reconstruction and performs the analysis directly on the onedimensional (ID) raw projection data (e.g., the individual radial spokes). In some embodiments, because the background anatomy has been subtracted, the ID difference profile along a given spoke will exhibit a localized signal anomaly (a peak or a trough) corresponding to the needle's physical intersection with that trajectory.

[0093] In some embodiments, to analyze this minimal data, the processing module applies ID signal processing algorithms, such as executing a derivative-based peak detection algorithm to identify local maxima or minima. In some embodiments, to prevent false positives, the system calculates the Full-Width at Half-Maximum (FWHM) of the detected anomaly and compares it against the known physical diameter of the interventional device. In some embodiments, if the FWHM matches the expected diameter, the processing module registers that ID coordinate as a valid intersection point.

[0094] In some embodiments, to determine the final device location, the system calculates the two-dimensional or three-dimensional crossing point of multiple validated spokes. In some embodiments, mathematically, each detected ID anomaly along a given projection readout defines a geometric line or plane extending perpendicular to that specific encoding angle. In some embodiments, the processing module computes the spatial intersection of these defined geometric boundaries. In some embodiments, utilizing more than two intersecting spokes, where slight physiological movement or field inhomogeneities may prevent a perfect single-point intersection, the intersecting lines form a geometric cluster. In some embodiments, the processing module applies a mathematical optimization algorithm, such as a least-squares regression, a center-of-mass calculation, or a probabilistic bounding box, to this cluster to output the highest-probability, multi-dimensional coordinate of the device tip.Image-Domain Analysis (Reconstructed Data Embodiment)

[0095] In some embodiments, wherein the acquired projection data is mathematically reconstructed into a multi-dimensional spatial matrix (e.g., a 2D Cartesian grid or a 3D volumetric space via Radon transform or system matrix inversion), the localization analysis transitions to the spatial image domain. In some embodiments, leveraging the a priori knowledge of the interventional device's physical geometry, the system's processing module executes advanced spatial filtering and multidimensional morphological pattern mapping algorithms directly on the reconstructed voxels to isolate the target signal.WSGR Docket No. 49880-720601

[0096] In some cases, the processing module may apply a spatial template matching algorithm or morphological operations (such as mathematical erosion and dilation) to the reconstructed difference dataset to identify contiguous voxel clusters conforming to the known cylindrical morphology of the interventional device. In some cases, because interventional devices such as biopsy needles exhibit a highly conserved, rigid linear structure, the processing module may apply a spatial transformation, such as a Hough transform, to the multi-dimensional dataset to algorithmically parameterize and extract the geometric line representing the needle shaft and tip.

[0097] In some embodiments, the processing module may execute a multiscale second-order derivative analysis, such as computing the Hessian matrix across the volumetric dataset. In some embodiments, by evaluating the eigenvalues of the Hessian matrix at each voxel, the system can selectively enhance continuous tubular structures (e.g., via a Frangi filter or similar vesselness enhancement algorithm) where the principal spatial curvatures indicate a high degree of linearity. In some embodiments, this second-order derivative analysis effectively decouples the cylindrical signal void of the needle from spherical background artifacts, unstructured thermal noise, or heterogeneous tissue boundaries, thereby yielding a highly accurate spatial segmentation of the device trajectory.

[0098] In some embodiments, to extract the linear trajectory of the interventional device, the processing module calculates the 3D Hessian matrix H at each voxel of the reconstructed volume, defined by the second-order partial derivatives of the image intensity I:d2I / dx2d2I / dxdy d2I / dxdzH = d2I / dydx d2I / dy2d2I / dydzd2l!dzdx d2I / dzdy d2I / dz2

[0099] In some embodiments, the system computes the three eigenvalues (Xi, , fa) of the Hessian matrix, ordered by magnitude (f < fa < fa). In some embodiments, to isolate the interventional device, the processing module applies a geometric filter condition. In some embodiments, because a biopsy needle geometrically approximates a rigid, dark tubular structure within a bright anatomical background (or vice versa), the system filters the voxels by isolating regions that satisfy the eigenvalue condition for a 3D line: fa « 0 (low curvature along the shaft), and fa « fa » 0 (high curvature across the cross-section). In some embodiments, voxels satisfying this condition are segmented as the needle shaft, effectively filtering out spherical artifacts or planar tissue boundaries.Neural Network Architectures and Model Implementations

[0100] In some embodiments, the steps of isolating the interventional device and determining its spatial coordinates are executed, augmented, or replaced by a trained artificial intelligence (Al)WSGR Docket No. 49880-720601model, such as a deep Artificial Neural Network (ANN). In some embodiments, depending on the processing domain, the system may deploy various network architectures, including but not limited to Convolutional Neural Networks (CNNs), Fully Convolutional Networks (FCNs) such as U-Net or V-Net architectures, or Recurrent Neural Networks (RNNs) for temporal tracking across sequential datasets.Deep Learning in the Projection Domain (End-to-End Regression)

[0101] In some embodiments, for ultra-fast tracking without image reconstruction, the system may employ an end-to-end deep learning regressor. In some embodiments, the raw, highly undersampled ID projection trajectories (or the ID difference profiles) are fed directly into the input layer of the neural network. In some embodiments, the network is configured to bypass classical mathematical crossing-point calculations entirely, instead utilizing a series of hidden layers to regress the data and directly output the predicted three-dimensional spatial coordinates (x, y, z) of the device tip.Deep Learning in the Image Domain (Volumetric Segmentation)

[0102] In some embodiments, utilizing reconstructed 2D or 3D datasets, the deep learning model acts as a highly advanced semantic segmenter, effectively replacing classical Hessian or morphological filters. In some embodiments, the multi-dimensional difference dataset is fed into a 3D CNN (e.g., a volumetric U-Net). In some embodiments, the network processes the spatial matrix to output a highly refined, voxel-wise probability mask that segments the structural void of the interventional device from surrounding tissue noise, heterogeneities, and susceptibility artifacts, thereby isolating the precise trajectory of the needle shaft.Model Training, Ground Truth, and Physics-Informed Loss Functions

[0103] In some embodiments, to achieve this functionality, the neural networks are pre-trained on a historical training dataset. In some embodiments, this training data comprises a plurality of prior hybrid-encoded MR signal datasets (e.g., baseline and post-insertion xSPEN / Fourier data) paired with ground-truth spatial coordinates of the interventional device. In some embodiments, the ground-truth data may be acquired via concurrent extrinsic tracking (e.g., optical trackers), high-resolution closed-bore MRI scans, or expert manual annotations.

[0104] In some embodiments, to ensure the neural network generates physically possible predictions, model training may utilize a physics-informed loss function. In some embodiments, during the b ackpropagation and weight-updating phase of training, the loss function mathematically penalizes the network for predicting device morphologies or trajectories that violate the physical limitation models of the interventional device. In some cases, the lossWSGR Docket No. 49880-720601function applies a steep penalty if the network predicts a needle bending angle that exceeds the known metallurgical flexibility of the specific biopsy needle gauge, forcing the deep learning model to converge on realistic, physically constrained tracking coordinates.Interventional Device

[0105] In some embodiments, the interventional device comprises a medical instrument, such as a biopsy needle, an ablation probe, or a catheter. In some embodiments, because the disclosed mathematical subtraction and anomaly isolation methods are highly sensitive to localized tissue displacement and signal voids, the system is capable of accurately tracking devices across a wide range of physical dimensions. In some embodiments, the interventional device comprises a medical needle having an outer diameter corresponding to a gauge size ranging from 10-gauge to 25-gauge. In some embodiments, particularly for biopsy and ablation procedures, the needle comprises a gauge size ranging from 13-gauge to 22-gauge. In some embodiments, it should be appreciated that the precise full width at half-maximum (FWHM) validation thresholds utilized by the algorithmic analysis module may be dynamically calibrated based on the known gauge size of the inserted device.Permanent Magnet

[0106] As discussed herein, and in accordance with various embodiments, the various systems, and various combinations of features that make up the various system embodiments, can include a permanent magnet.

[0107] FIGS. 3A-3B is a schematic illustration of a magnetic resonance imaging system 1200, In some cases. The system 300 includes a housing 320. As shown in FIGS. 3A-3B, the housing 320 includes a permanent magnet 330, a radio frequency transmit coil 340, a gradient coil set 350, an optional electromagnet 360, a radio frequency receive coil 370, and a power source 380. In some cases, the system 300 can include various electronic components, such as for example, but not limited to a varactor, a PIN diode, a capacitor, or a switch, including a micro-electro-mechanical system (MEMS) switch, a solid-state relay, or a mechanical relay. In some cases, the various electronic components listed above can be configured with the radio frequency transmit coil 340.

[0108] FIG. 3A is a schematic illustration of a magnetic resonance imaging system 300, In some cases. FIG. 3B illustrates an exploded view of the magnetic resonance imaging system 300. FIG. 3C is a schematic front view of the magnetic resonance imaging system 300, In some cases. FIG. 3D is a schematic side view of the magnetic resonance imaging system 300, In some cases. As shown in FIG. 3A and FIG. 3B, the magnetic resonance imaging system 300 includes aWSGR Docket No. 49880-720601housing 320. The housing 320 includes a front surface 325. In some cases, the front surface 325 can be a concave front surface. In some cases, the front surface 325 can be a recessed front surface.

[0109] In some cases, the permanent magnet 330 provides a static magnetic field in a region of interest 390 (also referred to herein as "given field of view"). In some cases, the permanent magnet 330 can include a plurality of cylindrical permanent magnets in parallel configuration as shown in FIG. 3C and FIG. 3D. In some cases, the permanent magnet 330 can include any suitable magnetic materials, including but not limited, to rare-earth based magnetic materials, such as, for example, Nd-based magnetic materials, and the like. As shown in FIG. 3 A, the main permanent magnet might include an access aperture 335 for accessing the patient from multiple sides of the system.

[0110] In some cases, the static magnetic field of the permanent magnet 230 may vary from about 50 mT to about 60 mT, about 45 mT to about 65 mT, about 40 mT to about 70 mT, about 35 mT to about 75 mT, about 30 mT to about 80 mT, about 25 mT to about 85 mT, about 20 mT to about 90 mT, about 15 mT to about 95 mT and about 10 mT to about 100 mT to a given field of view. The magnetic field may also vary from about 10 mT to about 15 mT, about 15 mT to about 20 mT, about 20 mT to about 25 mT, about 25 mT to about 30 mT, about 30 mT to about 35 mT, about 35 mT to about 40 mT, about 40 mT to about 45 mT, about 45 mT to about 50 mT, about 50 mT to about 55 mT, about 55 mT to about 60 mT, about 60 mT to about 65 mT, about 65 mT to about 70 mT, about 70 mT to about 75 mT, about 75 mT to about 80 mT, about 80 mT to about 85 mT, about 85 mT to about 90 mT, about 90 mT to about 95 mT, and about 95 mT to about 100 mT. In some cases, the static magnetic field of the permanent magnet 230 may also vary from about 1 mT to about 1 T, about 10 mT to about 195 mT, about 15 mT to about 900 mT, about 20 mT to about 800 mT, about 25 mT to about 700 mT, about 30 mT to about 600 mT, about 35 mT to about 500 mT, about 40 mT to about 400 mT, about 45 mT to about 300 mT, about 50 mT to about 200 mT, about 50 mT to about 100 mT, about 45 mT to about 100 mT, about 40 mT to about 100 mT, about 35 mT to about 100 mT, about 30 mT to about 100 mT, about 25 mT to about 100 mT, about 20 mT to about 100 mT, and about 15 mT to about 100 mT.[OHl] In some cases, the permanent magnet 330 can include a bore 335 in its center. In some cases, the permanent magnet 330 may not include a bore. In some cases, the bore 335 can have a diameter between 1 inch and 20 inches. In some cases, the bore 335 can have a diameter between 1 inch and 4 inches, between 4 inches and 8 inches, and between 10 inches and 20 inches. In some cases, the given field of view can be a spherical or cylindrical field of view, as shown inWSGR Docket No. 49880-720601FIG. 3 A and FIG. 3B. In some cases, the spherical field of view can be between 2 inches and 20 inches in diameter. In some cases, the spherical field of view can have a diameter between 1 inch and 4 inches, between 4 inches and 8 inches, and between 10 inches and 20 inches. In some cases, the cylindrical field of view is approximately between 2 inches and 20 inches in length. In some cases, the cylindrical field of view can have a length between 1 inch and 4 inches, between 4 inches and 8 inches, and between 10 inches and 20 inches.

[0112] In some cases, the permanent magnet system can be rotated 90 degrees such that the system has an imaging field of view on top of the system. This field of view can allow a patient to sit down on top of the system so that the biological material can be imaged with gravity affecting the tissues and structures.Radio Frequency Transmit Coil

[0113] As discussed herein, and in some cases, the various systems, and various combinations of features that make up the various system embodiments, can also include a radio frequency transmit coil.

[0114] FIG. 4 is a schematic view of an implementation of a magnetic imaging apparatus 1400, according to various embodiments. As shown in FIG. 4, the apparatus 400 includes a radio frequency transmit coil 420 that projects the RF power outwards away from the coil 420. The coil 420 has two rings 422 and 424 that are connected by one or more rungs 426. As shown in FIG. 4, the coil 420 is also connected to a power source 450a and / or a power source 450b (collectively referred to herein as "power source 450"). In some cases, power sources 450a and 450b can be configured for power input and / or signal input and can be referred to as coil input. In some cases, the power source 450a and / or 450b are configured to provide contact via electrical contacts 452a and / or 452b (collectively referred to herein as "electrical contact 452"), and electrical contacts 454a and / or 454b (collectively referred to herein as "electrical contact 454") by attaching the electrical contacts 452 and 454 to one or more rungs 426. The coil 420 is configured to project a uniform RF field within a field of view 440. In some cases, the field of view 440 is a region of interest for magnetic resonance imaging (i.e., imaging region) where a patient resides. Since the patient resides in the field of view 440 away from the coil 420, the apparatus 400 is suitable for use in a single-sided magnetic resonance imaging system. In some cases, the coil 420 can be powered by two signals that are 90 degrees out of phase from each other, for example, via quadrature excitation.

[0115] In some cases, the coils can be comprised of two or more orthogonal figure-8 shapes arranged on the surface of the magnetic surface. These coils can then be tuned to the same or toWSGR Docket No. 49880-720601different RF resonant frequencies. These coils are designed to generate a uniform or varying magnetic RF field within the region of interest that is off-of the face of the magnet.

[0116] In some cases, the coil 420 includes the ring 422 and the ring 424 that are positioned coaxially along the same axis but at a distance away from each other, as shown in FIG. 4. In some cases, the ring 422 and the ring 424 are separated by a distance ranging from about 0.1 m to about 10 m. In some cases, the ring 422 and the ring 424 are separated by a distance ranging from about 0.2 m to about 5 m, about 0.3 m to about 2 m, about 0.2 m to about 1 m, about 0.1 m to about 0.8 m, or about 0.1 m to about 1 m, inclusive of any separation distance therebetween. In some cases, the coil 420 includes the ring 422 and the ring 424 that are positioned non-co-axially but along the same direction and separated at a distance ranging from about 0.2 m to about Sm. In some cases, the ring 422 and the ring 424 can also be tilted with respect to each other. In some cases, the tilt angle can be from 1 degree to 90 degrees, from 1 degree to 5 degrees, from 5 degrees to 10 degrees, from 10 degrees to 25 degrees, from 25 degrees to 45 degrees, and from 45 degrees to 90 degrees.

[0117] In some cases, the ring 422 and the ring 424 have the same diameter. In some cases, the ring 422 and the ring 424 have different diameters and the ring 422 has a larger diameter than the ring 424, as shown in FIG. 4. In some cases, the ring 422 and the ring 424 have different diameters and the ring 422 has a smaller diameter than the ring 424. In some cases, the ring 422 and the ring 424 of the coil 420 are configured to create the imaging region in the field of view 440 containing a uniform RF power profile within the field of view 440, a field of view that is not centered within the RF-TX coil and is instead projected outwards in space from the coil itself.

[0118] In some cases, the ring 422 has a diameter between about 10 pm and about 10 m. In some cases, the ring 422 has a diameter between about 0.001 m and about 9 m, between about 0.01 m and about 8 m, between about 0.03 m and about 6 m, between about 0.05 m and about 5 m, between about 0.1 m and about 3 m, between about 0.2 m and about 2 m, between about 0.3 m and about 1.5 m, between about 0.5 m and about 1 m, or between about 0.01 m and about 3 m, inclusive of any diameter therebetween.

[0119] In some cases, the ring 424 has a diameter between about 10 pm and about 10 m. In some cases, the ring 424 has a diameter between about 0.001 m and about 9 m, between about 0.01 m and about 8 m, between about 0.03 m and about 6 m, between about 0.05 m and about 5 m, between about 0.1 m and about 3 m, between about 0.2 m and about 2 m, between about 0.3 m and about 1.5 m, between about 0.5 m and about 1 m, or between about 0.01 m and about 3 m, inclusive of any diameter therebetween.WSGR Docket No. 49880-720601

[0120] In some cases, the ring 422 and the ring 424 are connected by one or more rungs 426, as shown in FIG. 4. In some cases, the one or more rungs 426 are connected to the ring 422 and 424 so as to form a single electrical circuit loop (or single current loop). As shown in FIG. 4, for example, one end of the one or more rungs 426 is connected to the electrical contact 452 of the power source 450 and another end of the one or more rungs 426 be connected to the electrical contact 454 so that the coil 420 completes an electrical circuit.

[0121] In some cases, the ring 422 is a discontinuous ring and the electrical contact 452 and the electrical contact 454 can be electrically connected to two opposite ends of the ring 422 to form an electrical circuit powered by the power source 450. Similarly, in some cases, the ring 424 is a discontinuous ring and the electrical contact 452 and the electrical contact 454 can be electrically connected to two opposite ends of the ring 424 to form an electrical circuit powered by the power source 450.

[0122] In some cases, the rings 422 and 424 are not circular and can instead have a cross section that is elliptical, square, rectangular, or trapezoidal, or any shape or form having a closed loop. In some cases, the rings 422 and 424 may have cross sections that vary in two different axial planes with the primary axis being a circle and the secondary axis having a sinusoidal shape or some other geometric shape. In some cases, the coil 420 may include more than two rings 422 and 424, each connected by rungs that span and connect all the rings. In some cases, the coil 420 may include more than two rings 422 and 424, each connected by rungs that alternate connection points between rings. In some cases, the ring 422 may contain a physical aperture for access. In some cases, the ring 422 may be a solid sheet without a physical aperture.

[0123] In some cases, the coil 420 generates an electromagnetic field (also referred to herein as "magnetic field") strength between about 1 pT and about 10 mT. In some cases, the coil 420 can generate a magnetic field strength between about 10 pT and about 5 mT, about 50 pT and about 1 mT, or about 100 pT and about 1 mT, inclusive of any magnetic field strength therebetween.

[0124] In some cases, the coil 420 generates an electromagnetic field that is pulsed at a radio frequency between about 1 kHz and about 2 GHz. In some cases, the coil 420 generates a magnetic field that is pulsed at a radio frequency between about 1 kHz and about 1 GHz, about 10 kHz and about 800 MHz, about 50 kHz and about 300 MHz, about 100 kHz and about 100 MHz, about 10 kHz and about 10 MHz, about 10 kHz and about 5 MHz, about 1 kHz and about 2 MHz, about 50 kHz and about 150 kHz, about 80 kHz and about 120 kHz, about 800 kHz and about 1.2 MHz, about 100 kHz and about 10 MHz, or about 1 MHz and about 5 MHz, inclusive of any frequencies therebetween.WSGR Docket No. 49880-720601

[0125] In some cases, the coil 420 is oriented to partially surround the region of interest. In some cases, the ring 422, the ring 424, and the one or more rungs 426 are non-planar to each other. Said another way, the ring 422, the ring 424, and the one or more rungs 426 form a three-dimensional structure that surrounds the region of interest where a patient resides. In some cases, the ring 422 is closer to the region of interest than the ring 424, as shown in FIG. 4. In some cases, the region of interest has a size of about 0.1 m to about 1 m. In some cases, the region of interest is smaller than the diameter of the ring 422. In some cases, the region of interest is smaller than both the diameter of the ring 424 and the diameter of the ring 422, as shown in FIG.4. In some cases, the region of interest has a size that is smaller than the diameter of the ring 422 and larger than the diameter of the ring 424.

[0126] In some cases, the ring 422, the ring 424, or the rungs 426 include the same material. In some cases, the ring 422, the ring 424, or the rungs 426 include different materials. In some cases, the ring 422, the ring 424, or the rungs 426 include hollow tubes or solid tubes. In some cases, the hollow tubes or solid tubes can be configured for air or fluid cooling. In some cases, each of the ring 422 or the ring 424 or the rungs 426 includes one or more electrically conductive windings. In some cases, the windings include litz wires or any electrical conducting wires. These additional windings can be used to improve performance by lowering the resistance of the windings at the desired frequency. In some cases, the ring 422, the ring 424, or the rungs 426 include copper, aluminum, silver, silver paste, or any high electrical conducting material, including metal, alloys or superconducting metal, alloys or non-metal. In some cases, the ring 422, the ring 424, or the rungs 426 may include metamaterials.

[0127] In some cases, the ring 422, the ring 424, or the rungs 426 may contain separate electrically non-conductive thermal control channels designed to maintain the temperature of the structure to a specified setting. In some cases, the thermal control channels can be made from electrically conductive materials and integrated as to carry the electrical current.

[0128] In some cases, the coil 420 includes one or more electronic components for tuning the magnetic field. The one or more electronic components can include a varactor, a PIN diode, a capacitor, or a switch, including a micro-electro-mechanical system (MEMS) switch, a solid-state relay, or a mechanical relay. In some cases, the coil can be configured to include any of the one or more electronic components along the electrical circuit. In some cases, the one or more components can include mu metals, dielectrics, magnetic, or metallic components not actively conducting electricity and can tune the coil. In some cases, the one or more electronic components used for tuning includes at least one of dielectrics, conductive metals, metamaterials, or magnetic metals. In some cases, tuning the electromagnetic field includesWSGR Docket No. 49880-720601changing the current or by changing physical locations of the one or more electronic components. In some cases, the coil is cryogenically cooled to reduce resistance and improve efficiency. In some cases, the first ring and the second ring comprise a plurality of windings or litz wires.

[0129] In some cases, the coil 420 is configured for a magnetic resonance imaging system that has a magnetic field gradient across the field of view. The field gradient allows for imaging slices of the field of view without using an additional electromagnetic gradient. As disclosed herein, the coil can be configured to generate a large bandwidth by combining multiple center frequencies, each with their own bandwidth. By superimposing these multiple center frequencies with their respective bandwidths, the coil 420 can effectively generate a large bandwidth over a desired frequency range between about 1 kHz and about 2 GHz. In some cases, the coil 420 generates a magnetic field that is pulsed at a radio frequency between about 10 kHz and about 800 MHz, about 50 kHz and about 300 MHz, about 100 kHz and about 100 MHz, about 10 kHz and about 10 MHz, about 10 kHz and about 5 MHz, about 1 kHz and about 2 MHz, about 50 kHz and about 150 kHz, about 80 kHz and about 120 kHz, about 800 kHz and about 1.2 MHz, about 100 kHz and about 10 MHz, or about 1 MHz and about 5 MHz, inclusive of any frequencies therebetween.Gradient Coil Set

[0130] As discussed herein, and in some cases, the various systems, and various combinations of features that make up the various system embodiments, can also include a gradient coil set.

[0131] FIG. 5 is a schematic view of an implementation of a magnetic imaging apparatus 500, according to various embodiments. As shown in FIG. 5, the apparatus 500 includes a gradient coil set 520 (also referred to herein as single-sided gradient coil set 520) that is configured to project a gradient magnetic field outwards away from the coil set 520 and within a field of view 530. In some cases, the field of view 530 is a region of interest for magnetic resonance imaging (i.e., imaging region) where a patient resides. Since the patient resides in the field of view 530 away from the coil set 520, the apparatus 500 is suitable for use in a single-sided MRI system.

[0132] As shown in the figure, the coil set 520 includes variously sized spiral coils in various sets of spiral coils 540a, 540b, 540c, and 540d (collectively referred to as "spiral coils 540"). Each set of the spiral coils 540 include at least one spiral coil and FIG. 5 is shown to include 3 spiral coils. In some cases, each spiral coil in the spiral coils 540 has an electrical contact at its center and an electrical contact output on the outer edge of the spiral coil so as to form a single running loop of electrically conducting material spiraling out from the center to the outer edge, or vice versa. In some cases, each spiral coil in the spiral coils 540 has a first electrical contact atWSGR Docket No. 49880-720601a first position of the spiral coil and a second electrical contact at a second position the spiral coil so as to form a single running loop of electrically conducting material from the first position to the second position, or vice versa.

[0133] As shown in FIG. 5, the coil set 520 also includes an aperture 525 at its center where the spiral coils 540 are disposed around the aperture 525. The aperture 525 itself does not contain any coil material within it for generating magnetic material. The coil set 520 also includes an opening 527 on the outer edge of the coil set 520 to which the spiral coils 540 can be disposed. Said another way, the aperture 525 and the opening 527 define the boundaries of the coil set 520 within which the spiral coils 540 can be disposed. In some cases, the coil set 520 forms a bowl shape with a hole in the center.

[0134] In some cases, the spiral coils 540 form across the aperture 525. For example, the spiral coils 540a are disposed across from the spiral coils 540c with respect to the aperture 525.Similarly, the spiral coils 540b are disposed across from the spiral coils 540d with respect to the aperture 525. In some cases, the spiral coils 540 in the coil set 520 shown in FIG. 5 are configured to create spatial encoding in the magnetic gradient field within the field of view 530.

[0135] As shown in FIG. 5, the coil set 520 is also connected to a power source 550 via electrical contacts 552 and 554 by attaching the electrical contacts 552 and 554 to one or more of the spiral coils 540. In some cases, the electrical contact 552 is connected to one of the spiral coils 540, which is then connected to other spiral coils 540 in series and / or in parallel, and one other spiral coil 540 is then connected to the electrical contact 554 so as to form an electrical current loop. In some cases, the spiral coils 540 are all electrically connected in series. In some cases, the spiral coils 540 are all electrically connected in parallel. In some cases, some of the spiral coils 540 are electrically connected in series while other spiral coils 540 are electrically connected in parallel. In some cases, the spiral coils 540a are electrically connected in series while the spiral coils 540b are electrically connected in parallel. In some cases, the spiral coils 540c are electrically connected in series while the spiral coils 540d are electrically connected in parallel. The electrical connections between each spiral coil in the spiral coils 540 or each set of spiral coils 540 can be configured as needed to generate the magnetic field in the field of view 530.

[0136] In some cases, the coil set 520 includes the spiral coils 540 spread out as shown in FIG.5. In some cases, each of the sets of spiral coils 540a, 540b, 540c, and 540d are configured in a line from the aperture 525 to the opening 527 so that each set of spiral coils is set apart from another by an angle of 90°. In some cases, 540a and 540b are set at 45° from one another, and 540c and 540d are set at 45° from one another, while 540c is set 135° on the other side of 540bWSGR Docket No. 49880-720601and 540d is set 135° on the other side of 540a. In essence, any of the sets of spiral coils 540 can be configured in any arrangement for any number "n" of sets of spiral coils 540.

[0137] In some cases, the spiral coils 540 have the same diameter. In some cases, each of the sets of spiral coils 540a, 540b, 540c, and 540d have the same diameter. In some cases, the spiral coils 540 have different diameters. In some cases, each of the sets of spiral coils 540a, 540b, 540c, and 540d have different diameters. In some cases, the spiral coils in each of the sets of spiral coils 540a, 540b, 540c, and 540d have different diameters. In some cases, 540a and 540b have the same first diameter and 540c and 540d have the same second diameter, but the first diameter and the second diameter are not the same.

[0138] In some cases, each spiral coil in the spiral coils 540 has a diameter between about 10 pm and about 10 m. In some cases, each spiral coil in the spiral coils 540 has a diameter between about 0.001 m and about 9 m, between about 0.005 m and about 8 m, between about 0.01 m and about 6 m, between about 0.05 m and about 5 m, between about 0.1 m and about 3 m, between about 0.2 m and about 2 m, between about 0.3 m and about 1.5 m, between about 0.5 m and about 1 m, or between about 0.01 m and about 3 m, inclusive of any diameter therebetween.

[0139] In some cases, the spiral coils 540 are connected to form a single electrical circuit loop (or single current loop). As shown in FIG. 5, for example, one spiral coil in the spiral coils 540 is connected to the electrical contact 552 of the power source 450 and another spiral coil is connected to the electrical contact 554 so that the spiral coils 540 completes an electrical circuit.

[0140] In some cases, the coil set 520 generates an electromagnetic field strength (also referred to herein as "electromagnetic field gradient" or "gradient magnetic field") between about 1 pT and about 10 T. In some cases, the coil set 520 can generate an electromagnetic field strength between about 100 pT and about 1 T, about 1 mT and about 500 mT, or about 10 mT and about 100 mT, inclusive of any magnetic field strength therebetween. In some cases, the coil set 520 can generate an electromagnetic field strength greater than about 1 pT, about 10 pT, about 100 pT, about 1 mT, about 5 mT, about 10 mT, about 20 mT, about 50 mT, about 100 mT, or about 500 mT.

[0141] In some cases, the coil set 520 generates an electromagnetic field that is pulsed at a rate with a rise-time less than about 100 ps. In some cases, the coil set 520 generates an electromagnetic field that is pulsed at a rate with a rise-time less than about 1 ps, about 5 ps, about 10 ps, about 20 ps, about 30 ps, about 40 ps, about 50 ps, about 100 ps, about 200 ps, about 500 ps, about 1 ms, about 2 ms, about 5 ms, or about 10 ms.

[0142] In some cases, the coil set 520 is oriented to partially surround the region of interest in the field of view 530. In some cases, the spiral coils 540 are non-planar to each other. In someWSGR Docket No. 49880-720601cases, the sets of spiral coils 540a, 540b, 540c, and 540d are non-planar to each other. Said another way, the spiral coils 540 and each of the sets of spiral coils 540a, 540b, 540c, and 540d form a three-dimensional structure that surrounds the region of interest in the field of view 530 where a patient resides.

[0143] In some cases, the spiral coils 540 include the same material. In some cases, the spiral coils 540 include different materials. In some cases, the spiral coils in set 540a include the same first material, the spiral coils in set 540b include the same second material, the spiral coils in set 540c include the same third material, the spiral coils in set 540d include the same fourth material, but the first, second, third and fourth materials are different materials. In some cases, the first and second materials are the same material, but that same material is different from the third and fourth materials, which are the same. In essence, any of the spiral coils 540 can be of the same material or different materials depending on the configuration of the coil set 520.

[0144] In some cases, the spiral coils 540 include hollow tubes or solid tubes. In some cases, the spiral coils 540 include one or more windings. In some cases, the windings include litz wires or any electrical conducting wires. In some cases, the spiral coils 540 include copper, aluminum, silver, silver paste, or any high electrical conducting material, including metal, alloys or superconducting metal, alloys or non-metal. In some cases, the spiral coils 540 include metamaterials.

[0145] In some cases, the coil set 520 includes one or more electronic components for tuning the magnetic field. The one or more electronic components can include a PIN diode, a mechanical relay, a solid-state relay, or a switch, including a micro electro-mechanical system (MEMS) switch. In some cases, the coil can be configured to include any of the one or more electronic components along the electrical circuit. In some cases, the one or more components can include mu metals, dielectrics, magnetic, or metallic components not actively conducting electricity and can tune the coil. In some cases, the one or more electronic components used for tuning includes at least one of conductive metals, metamaterials, or magnetic metals. In some cases, tuning the electromagnetic field includes changing the current or by changing physical locations of the one or more electronic components. In some implementations, the coil is cryogenically cooled to reduce resistance and improve efficiency.Electromagnet

[0146] As discussed herein, and in some cases, the various systems, and various combinations of features that make up the various system embodiments, can also include an electromagnet.

[0147] FIG. 6 is a schematic front view of a magnetic resonance imaging system 600, according to various embodiments. In some cases, the system 600 can be any magnetic resonance imagingWSGR Docket No. 49880-720601system, including for example, a single-sided magnetic resonance imaging system that comprises a magnetic resonance imaging scanner or a magnetic resonance imaging spectrometer, as disclosed herein.

[0148] As shown in FIG. 6, the system 600 includes a housing 620 that can house various components, including, for example but not limited to, magnets, electromagnets, coils for producing radio frequency fields, various electronic components, for example but not limited to, for controlling, powering, and / or monitoring of the system 600. In some cases, the housing 620 can house, for example, the permanent magnet 330, the radio frequency transmit coil 340, and / or the gradient coil set 350 within the housing 620. In some cases, the system 600 also includes a bore 635 in its center. As shown in FIG. 6, the housing 620 also includes a front surface 625 of the system 600. In some cases, the front surface 625 can be curved, flat, concave, convex, or otherwise have a straight or curvilinear surface. In some cases, the magnetic resonance imaging system 600 can be configured to provide a region of interest in field of view 630.

[0149] As shown in FIG. 6, the system 600 includes an electromagnet 660 disposed proximate to the front surface 625 of the system 600. In some cases, the electromagnet 660 is disposed proximate to the center of the front surface 625 on the front side of the system 600. In some cases, the electromagnet 660 can be a solenoid coil configured to create a field that either adds or subtracts from the magnetic field, for example, of the permanent magnet 330. In some cases, this field can create a prepolarizing field for enhancing the signal or contrast from nuclear magnetic resonance.

[0150] As shown in FIG. 6, the given field of view 630 resides at the center of the front surface 625 of the system 600. In some cases, the electromagnet 660 is disposed within the given field of view 630. In some cases, the electromagnet 660 is disposed concentrically with the given field of view 630. In some cases, the electromagnet 660 can be inserted in the bore 635. In some cases, the electromagnet 660 can be placed proximate to the bore 635. For example, the electromagnet 660 can be placed in front, back, or middle of the bore 635. In some cases, the electromagnet 660 can be placed proximate to, or at the entrance of the bore 635.Radio Frequency Receive Coil

[0151] As discussed herein, and in some cases, the various systems, and various combinations of features that make up the various system embodiments, can also include a radio frequency receive coil.

[0152] Some MR systems can create a uniform field within the imaging region. This uniform field can then generate a narrow band of magnetic resonance frequencies that can then be captured by a receive coil, amplified, and digitized by a spectrometer. Since frequencies areWSGR Docket No. 49880-720601within a narrow, well-defined bandwidth, hardware architecture can be focused on creating a statically tuned RF-RX coil with an optimal coil quality factor. Many variations in coil architectures have been created that explore large single volume coils, coil arrays, parallelized coil arrays, or body specific coil arrays. However, these structures may be limited to imaging a specific frequency close to the region of interest at high field strengths and with a limited sized region of interest within a magnetic bore.

[0153] In some cases, an MRI system is provided that can include an imaging region that can be offset from the face of a magnet. The MRI system can provide relatively unobstructed imaging. The MRI system can have a built-in magnetic field gradient that creates a range of field values over the region of interest. The MRI system can operate at a lower magnetic field strength as compared to other MRI systems allowing for a relaxation on the RX coil design constraints and allowing for additional mechanisms like robotics to be used with the MRI.

[0154] The architecture of the main magnetic field of the MRI system, in some cases, can create a different set of optimization constraints. Because the imaging volume can extend over a broader range of magnetic resonance frequencies, the hardware can be configured to be sensitive to and capture the specific frequencies that are generated across the field of view. This frequency spread can be much larger than a single receive coil tuned to a single frequency and can provide increased sensitivity. In addition, because the field strength can be much lower than other MRI systems, and because signal intensity can be proportional to the field strength, it can allow for a maximization of a signal to noise ratio of the receive coil network. Methods are therefore provided, in some cases, to acquire the full range of frequencies that are generated within the field of view without loss of sensitivity.

[0155] In some cases, several methods are provided that can allow for imaging within the MRI system. These methods can include combining: (i) a variable tuned RF-RX coil; (ii) a RF-RX coil array with elements tuned to frequencies that are dependent upon the spatial inhomogeneity of the magnetic field; (iii) an ultralow-noise pre-amplifier design; and (iv) an RF-RX array with multiple receive coils designed to optimize the signal from a defined and limited field of view for a specific body part. These methods can be combined in any combination as needed.

[0156] In some cases, a variable tuned RF-RX coil can comprise one or more electronic components for tuning the electromagnetic receive field. In some cases, the one or more electronic components can include at least one of a varactor, a PIN diode, a capacitor, an inductor, a MEMS switch, a solid-state relay, or a mechanical relay. In some cases, the one or more electronic components used for tuning can include at least one of dielectrics, capacitors, inductors, conductive metals, metamaterials, or magnetic metals. In some cases, tuning theWSGR Docket No. 49880-720601electromagnetic receive field includes changing the current or changing physical locations of the one or more electronic components. In some cases, the coil is cryogenically cooled to reduce resistance and improve efficiency.

[0157] In some cases, the RF-RX array can be comprised of individual coil elements that are each tuned to a variety of frequencies. The appropriate frequency can be chosen, for example, to match the frequency of the magnetic field located at the specific spatial location where the specific coil is located. Because the magnetic field can vary as a function of space, as shown in FIG. 7A, the field and frequency of the coil can be adjusted to approximately match the spatial location. Here the coils can be designed to image the field locations Bl, B2, and B3, which are physically separated along a single axis.

[0158] For this low field system, in some cases, a low-noise preamplifier can be designed and configured to leverage the low signal environment of the MRI system. This low noise amplifier can be configured to utilize components that do not generate significant electronic and voltage noise at the desired frequencies (for example, < 3 MHz and >2 MHz). Typical junction field effect transistor designs (J-FET) may not have the appropriate noise characteristics at this frequency and can create high frequency instabilities at the GHz range that can bleed into, although several decades of dB lower, into the measured frequency range. Since the gain of the system can preferably be, for example, > 80 dB overall, any small instabilities or intrinsic electrical noise can be amplified and degrade signal integrity.

[0159] Referring to FIG. 7B, RF-RX coils can be designed to image specific limited field of views based upon the target anatomy. The vagina and prostate, for example, extends to about 100 millimeters deep within the human body (see FIG. 7D). Thus, a RX coil for vaginal or prostate imaging can be able to image at least about 100 mm deep inside the human body.According to the Biot Savart law, the magnetic field of a loop coil can be calculated by the following equation,p02n * R2* IBz = - - 7(Z2+ R2)|where pO = 4'7i * 10-7H / m is the vacuum permeability, R is the radius of the loop coil, z is distance along the center line of the coil from its center, and I is the current on the coil (see FIG. 7B). Assuming 1 = 1 Ampere, with the goal of locating a figure of magnetic field (Bz) at z = 100 mm, the maximum position is when R is 140 mm, as shown in FIG. 7C. In some cases, the RF RX coil network is configured for imaging external to the surface by a distance ranging from about 80 mm to about 120 mm to account for anatomical differences across patients.WSGR Docket No. 49880-720601

[0160] Based upon the geometrical constraints of the body, the loop coil can be set up at the space between the human legs upon the torso. These anatomical constraints provide a difficulty for fitting a 280-mm diameter coil at this location. According to FIG. 7C, the Bz field value is proportional to the radius of the loop when R is less than 140mm. As such, it is advantageous that the coil approach a diameter as large as can be accommodated. For example, the largest loop coil that can be placed between a person’s legs can be about 10 cm large.

[0161] As the size of the coil is limited by the space between legs, the magnetic field of a 10-cm diameter coil may not be capable of reaching the depth of the vagina or prostate. Therefore, a single coil may not be enough for POP imaging. Thus, multiple coils can prove beneficial in receiving signal from different directions. In various embodiments of the MRI system, the magnetic field is provided in the z-direction and RF coils are sensitive to x- and y-direction. In this example case, a loop coil in x-y plane may not collect RF signal from a human since it is sensitive to z-direction, while a butterfly coil may be useful. Based on the location and orientation of an RF coil, the RF coil can be a loop coil or a butterfly coil. In addition, an RF coil can be placed under the body of a subject without limiting the size of the RF coil.

[0162] In some embodiments, the MRI system comprises a plurality of RX coils. In some embodiments, one or more RX coils of the plurality of RX coils can be decoupled. Decoupling the one or more RX couples can comprise: geometry decoupling, capacitive or inductive decoupling, or low or high impedance pre-amplifier coupling.

[0163] The MRI system, in some cases, can have a variant magnetic field from the magnet, and its strength can vary linearly along the z direction. The RX coils can be located in different positions in z-direction, and each coil can be tuned to different frequencies, which can depend on the location of the coils in the system.

[0164] In some embodiments, the RX coils can be constructed from conductive traces that can be pre-tuned to a desired frequency and printed, for example, on a disposable substrate. In some embodiments, a clinician can place the RX coil (or a plurality of RX coils configured in an array) upon the body at the region of interest for a given procedure and dispose of the coil afterwards. For example, and in some cases, the RX coils can be surface coils, which can be affixed to, e.g., worn or taped to, a patient's body. For other body parts, e.g., an ankle or a wrist, the surface coil might be a single-loop configuration, figure-8 configuration, or butterfly coil configuration wrapped around the region of interest. For regions that require significant penetration depth, e.g., the torso or knee, the coil might consist of a Helmholtz coil pair. The main restriction to the receive coil is similar to other MRI systems: the coil can be sensitive to a plane that is orthogonal to the main magnetic field, BO, axis. FIG. 12 is a schematic view of figure-8 coils 1202 disposedWSGR Docket No. 49880-720601within the housing of an MRI system proximate to the surface 1204. In some embodiments, the figure-8 coils 1202 cover the entirety of an underside of the surface 1204. In some embodiments, the coils can be disposed on an underside of a commode. In some embodiments, the MRI system described herein can comprise the commode.

[0165] In some cases, the coils might be inductively coupled to another loop that is electrically connected to the receive preamplifier. This design can allow for easier and unobstructed access of the receive coils.

[0166] In some cases, the size of coils can be limited by the structure of the human body. For example, the coils' size can be positioned and configured to fit in the space between human legs when imaging the vagina or prostate.

[0167] In some cases, the number of turns and loops of the RX coil can be adapted to cover the entire space between the legs so that the entire imaging volume can be covered.Programmable Logic Controller

[0168] As discussed herein, and in some cases, the various systems, and various combinations of features that make up the various system embodiments, can also include a programmable logic controller (PLC). PLCs are industrial digital computers which can be designed to operate reliably in harsh usage environments and conditions. PLCs can be designed to handle these types of conditions and environments, not just in the external housing, but in the internal components and cooling arrangements as well. As such, PLCs can be adapted for the control of manufacturing processes, such as assembly lines, or robotic devices, or any activity that requires high reliability control and ease of programming and process fault diagnosis.

[0169] In some cases, the system can contain a PLC that can control the system in pseudo realtime. This controller can manage the power cycling and enabling of the gradient amplifier system, the radio frequency transmission system, the frequency tuning system, and sends a keep alive signal (e.g., a message sent by one device to another to check that the link between the two is operating, or to prevent the link from being broken) to the system watchdog. The system watchdog can continually look for a strobe signal supplied by the computer system. If the computer threads stall, a strobe is missed that can trigger the watchdog to enter a fault condition. If the watchdog enters a fault condition, the watchdog can be operated to depower the system.

[0170] The PLC can handle low level logic functions on incoming and outgoing signals into system. This system can monitor the subsystem health and control when subsystems needed to be powered or enabled. The PLC can be designed in different ways. One design example includes a PLC with one main motherboard with four expansion boards. Due to the speed of theWSGR Docket No. 49880-720601microcontroller on the PLC, subsystems can be managed in pseudo real-time, while real-time applications can be handled by the computer or spectrometer on the system.

[0171] The PLC can serve many functional responsibilities including, for example, powering on / off the gradient amplifiers (discussed in greater detail herein) and the RF amplifier (discussed in greater detail herein), enabling / disabling the gradient amplifiers and the RF amplifier, setting the digital and analog voltages for the RF coil tuning, and strobing the system watchdog.Robot

[0172] As discussed herein, and in some cases, the various systems, and various combinations of features that make up the various system embodiments, can also include a robot.

[0173] In some medical procedures, such as a prostate biopsy, it is typical for the patient to endure a lengthy procedure in an uncomfortable prone position, which often includes remaining motionless in one specific body position during the entire procedure. In such long procedures, if a metallic ferromagnetic needle is used for the biopsy with guidance from an MRI system, the needle may experience attraction force from the strong magnets of the MRI system, and thus may cause it to deviate from its path during the length of the procedure. Even in the case of using a non-magnetic needle, the local field distortions can cause distortions in the magnetic resonance images, and therefore, the image quality surrounding the needle may result in a poor quality. To avoid such distortions, pneumatic robots with complex compressed air mechanism have been designed to work in conjunction with conventional MRI systems. Even then, access to target anatomy remains challenging due to the form factor of currently available MRI systems.

[0174] The various embodiments presented herein include improved MRI systems that are configured to use for guiding in medical procedures, including, for example, robot-assisted, invasive medical procedures. The technologies, methods and apparatuses disclosed herein relate to a guided robotic system using magnetic resonance imaging as a guidance to automatically guide a robot (referred to herein as "a robotic system") in medical procedures. In some cases, the disclosed technologies combine a robotic system with magnetic resonance imaging as guidance. In some cases, the robotic system disclosed herein is combined with other suitable imaging techniques, for example, ultrasound, x-ray, laser, or any other suitable diagnostic or imaging methodologies.Spectrometer

[0175] As discussed herein, and in some cases, the various systems, and various combinations of features that make up the various system embodiments, can also include a spectrometer.WSGR Docket No. 49880-720601

[0176] A spectrometer can operate to control all real-time signaling used to generate images. It creates the RF transmission (RF-TX) waveform, gradient waveforms, frequency tuning trigger waveform, and blanking bit waveforms. These waveforms are then synchronized with the RF receiver (RF-RX) signals. This system can generate frequency swept RF-TX pulses and phase cycled RF-TX pulses. The swept RF-TX pulses allow for an inhomogeneous B1+ field (RF-TX field) to excite a sample volume more effectively and efficiently. It can also digitize multiple RF RX channels with the current configuration set to four receiver channels. However, this system architecture allows for an easy system scale-up to increase the number of transmit and receive channels to a maximum of 32 transmit channels and 16 receive channels without having to change the underlying hardware or software architecture.

[0177] The spectrometer can serve many functional responsibilities including, for example, generating and synchronizing the RF-TX (discussed in greater detail herein) waveforms, X gradient waveforms, Y-gradient waveforms, blanking bit waveforms, frequency tuning trigger waveform and RF-RX windows, and digitizing and signal processing the RF-RX data using, for example, quadrature demodulation followed by a finite impulse response filter decimation such as, for example, a cascade integrating comb (CIC) filter decimation.

[0178] The spectrometer can be designed in different ways. One design example includes a spectrometer with three main components: 1) a first software design radio (SDR 1) operating with Basic RF-TX daughter cards and Basic RF-RX daughter cards; 2) a second software design radio (SDR 2) operating with LFRF TX daughter cards and Basic RF-RX daughter cards; and 3) a clock distribution module (octoclock) that can synchronize the two devices.

[0179] SDRs are the real-time communication device between the transmitted signals and received MRI signals. They can communicate over 10-Gbit optical fiber to the computer using a Small Form-factor Pluggable Plus transceiver (SFP+) communication protocol. This communication speed can allow the waveforms to be generated with high fidelity and high reliability.

[0180] Each SDR can include a motherboard with an integrated field-programmable gate array (FPGA), digital to analog converters, analog to digital converters, and four module slots for integrating different daughtercards. Each of these daughtercards can function to change the frequency response of the associated TX or RX channel. In some cases, the system can utilize many variations of daughtercards including, for example, a Basic RF version, and a low frequency (LP) RF version. The Basic RF daughtercards can be used for generating and measuring RF signals. The LP RF version can be used for generating gradient, trigger and blanking bit signals.WSGR Docket No. 49880-720601

[0181] The octoclock can be used to synchronize a multi-channel SDR system to a common timing source while providing high-accuracy time and frequency reference distribution. It can do so, for example, with 8-way time and frequency distribution (1 PPS and 10MHz). An example of an octoclock is the Ettus Octoclock CD A, which can distribute a common clock to up to eight SDRs to ensure phase coherency between the two or more SDR sources.RE Amplifier / Gradient Amplifier

[0182] As discussed herein, and in some cases, the various systems, and various combinations of features that make up the various system embodiments, can also include a radio frequency amplifier (RF amplifier) and a gradient amplifier.

[0183] A RF amplifier is a type of electronic amplifier that can convert a low-power radiofrequency signal into a higher power signal. In operation, the RF amplifier can accept signals at low amplitudes and provide, for example, up to 60 dB of gain with a flat frequency response. This amplifier can accept three phase AC input voltage and can have a 10% max duty cycle. The amplifier can be gated by a 5 V digital signal so that unwanted noise is not generated when the MRI is receiving signal.

[0184] In operation, a gradient amplifier can increase the energy of the signal before it reaches the gradient coils such that the field strength can be intense enough to produce the variations in the main magnetic field for localization of the later received signal. The gradient amplifier can have two active amplification channels that can be controlled independently. Each channel can send out current to either the X or Y channel. The third axis of spatial encoding can be handled by a permanent gradient in the main magnetic field (BO). With varying combinations of pulse sequences, the signal can be localized in three dimensions and reconstructed to create an object.Display / GUI

[0185] As discussed herein, and in some cases, the various systems, and various combinations of features that make up the various system embodiments, can also include a display in the form of, for example, a graphical user interface (GUI). In some cases, the GUI can take any contemplated form necessary to convey the information necessary to run magnetic resonance imaging procedures.

[0186] Further, it can be appreciated that the display may be embodied in any of a number of other forms, such as, for example, a rack-mounted computer, mainframe, supercomputer, server, client, a desktop computer, a laptop computer, a tablet computer, hand-held computing device (e.g., PDA, cell phone, smart phone, palmtop, etc.), cluster grid, netbook, embedded systems, orWSGR Docket No. 49880-720601any other type of special or general purpose display device as may be desirable or appropriate for a given application or environment.

[0187] The GUI is a system of interactive visual components for computer software. A GUI can display objects that convey information and represent actions that can be taken by the user. The objects change color, size, or visibility when the user interacts with them. GUI objects include, for example, icons, cursors, and buttons. These graphical elements are sometimes enhanced with sounds, or visual effects like transparency and drop shadows.

[0188] A user can interact with a GUI using an input device, which can include, for example, alphanumeric and other keys, mouse, a trackball or cursor direction keys for communicating direction information and command selections to a processor and for controlling cursor movement on the display. An input device may also be the display configured with touchscreen input capabilities. This input device can have two degrees of freedom in two axes, a first axis (i.e., x) and a second axis (i.e., y), that allows the device to specify positions in a plane.However, it can be understood that input devices allowing for 3 -dimensional (x, y and z) cursor movement are also contemplated herein.

[0189] In some cases, the touchscreen, or touchscreen monitor, can serve as the primary human interface device that allows a user to interact with the MRI. The screen can have a projected capacitive touch sensitive display with an interactive virtual keyboard. The touchscreen can have several functions including, for example, displaying the graphical user interface (GUI) to the user, relaying user input to the system's computer, and starting or stopping a scan.

[0190] In some cases, GUI views can be screens displayed (Qt widgets) to the user with appropriate buttons, edit fields, labels, images, etc. These screens can be constructed using a designer tool such as, for example, the Qt designer tool, to control placement of widgets, their alignment, fonts, colors, etc. A user interface (UI) sub controller can possess modules configured to control the behavior (display and responses) of the respective view modules.

[0191] Several application utilities (App Util) modules can perform specific functions. For example, S3 modules can handle data communication between the system and, for example, Amazon Web Services (AWS). Event Filters can be present to ensure valid characters are displayed on screen when user inputs are required. Dialog messages can be used to show various status, progress messages, or require user prompts. Moreover, a system controller module can be utilized to handle coordination between the sub controller modules, and key data processing blocks in the system, the pulse sequence generator, pulse interpreter, spectrometer and reconstruction.WSGR Docket No. 49880-720601Processing Module

[0192] As discussed herein, and in some cases, the various workflows or methods, and various combinations of steps that make up the various workflow or method embodiments, can also include a processing module.

[0193] In some cases, a processing module serves many functions. For example, a processing module can operate to receive signal data acquired during the scan, process the data, and reconstruct those signals to produce an image that can be viewed (for example, via a touchscreen monitor that displays a GUI to the user), analyzed and annotated by system users. To create an image, an NMR signal can be localized in three-dimensional space. Magnetic gradient coils localize the signal and are operated before or during the RF acquisition. By prescribing a RF and gradient coil application sequence, called a pulse sequence, the signals acquired correspond to a specific magnetic field and RF field arrangement. Using mathematical operators and image reconstruction techniques, arrays of these acquired signals can be reconstructed into an image. These images can be generated from simple linear combinations of magnetic field gradients. In some cases, the system can operate to reconstruct the acquired signals from a-priori knowledge of, for example, the gradient fields, RF fields, and pulse sequences.

[0194] In some cases, the processing module can also operate to compensate for patient motion during a scan procedure. Motion (e.g., beating heart, breathing lungs, bulk patient movement) is one of the most common sources of artifacts in MRI, with such artifacts affecting image quality by leading to misinterpretations in the images and a subsequent loss in diagnostic quality.Therefore, motion compensation protocols can help address these issues at minimal cost in time, spatial resolution, temporal resolution, and signal-to-noise ratio.

[0195] In some cases, the processing module might include artificial intelligence machine learning modules designed to denoise the signal and improve the image signal-to-noise ratio.

[0196] In some cases, the processing module can also operate to assist clinicians in planning a path for subsequent patient intervention procedures, such as biopsy. In some cases, a robot can be provided as part of the system to perform the intervention procedure. The processing module can communicate instructions to the robot, based on image analysis, to properly access, for example, the appropriate region of the body requiring a biopsy.

[0197] FIG. 8 is a flowchart for a method SI 00 of performing magnetic resonance imaging, according to various embodiments. In some cases, the method S1O0 includes inputting patient parameters into a magnetic resonance imaging system at step SI 10. In some cases, the system includes a housing having a front surface, a permanent magnet for providing a static magnetic field, a radio frequency transmit coil, and a single-sided gradient coil set. In some cases, theWSGR Docket No. 49880-720601radio frequency transmit coil and the single-sided gradient coil set are positioned proximate to the front surface. In some cases, the system includes an electromagnet, a radio frequency receive coil, and a power source. In some cases, the power source is configured to flow current through at least one of the radio frequency transmit coil, the single-sided gradient coil set, or the electromagnet to generate an electromagnetic field in a region of interest. In some cases, the region of interest resides outside the front surface.

[0198] As shown in FIG. 8, the method SI 00 also includes executing a patient positioning protocol comprising running at least one first scan at step S120, running at least one second scan at step SI 30, reviewing the at least one second scan at step SI 40, and determining at least one path for conducting a biopsy based on review of the at least one second scan at step SI 50.

[0199] In some cases, the radio frequency transmit coil and the single-sided gradient coil set are located on the front surface. In some cases, the front surface is a concave surface. In some cases, the permanent magnet has an aperture through the center of the permanent magnet. In some cases, the static magnetic field of the permanent magnet ranges from 1 mT to 1 T. In some cases, the static magnetic field of the permanent magnet ranges from 10 mT to 195 mT.

[0200] In some cases, the radio frequency transmit coil includes a first ring and a second ring that are connected via one or more capacitors and / or one or more rungs. In some cases, the radio frequency transmit coil is non-planar and oriented to partially surround the region of interest. In some cases, the single-sided gradient coil set is non-planar and oriented to partially surround the region of interest. In some cases, the single-sided gradient coil set is configured to project a magnetic field gradient to the region of interest. In some cases, the single-sided gradient coil set includes one or more first spiral coils at a first position and one or more second spiral coils at a second position, the first position and the second position being located opposite each other about a center region of the single-sided gradient coil set. In some cases, the single-sided gradient coil set has a rise time less than 10 ps.

[0201] In some cases, the electromagnet is configured to alter the static magnetic field of the permanent magnet within the region of interest. In some cases, the electromagnet has a magnetic field strength from 10 mT to 1 T. In some cases, the radio frequency receive coil is a flexible coil configured to be affixed to an anatomical portion of a patient for imaging within the region of interest. In some cases, the radio frequency receive coil is in one of a single-loop coil configuration, figure-8 coil configuration, or butterfly coil configuration, wherein the coil is smaller than the region of interest. In some cases, the radio frequency transmit coil and the single-sided gradient coil set are concentric about the region of interest. In some cases, theWSGR Docket No. 49880-720601magnetic resonance imaging system is a single-sided magnetic resonance imaging system that comprises a bore having an opening positioned about a center region of the front surface.

[0202] FIG. 9 is a flowchart for a method S200 of performing magnetic resonance imaging, according to various embodiments. In some cases, the method S200 includes inputting patient parameters into a magnetic resonance imaging system at step S210. In some cases, the system includes a housing having a concave front surface, a permanent magnet for providing a static magnetic field, a radio frequency transmit coil, and at least one gradient coil set. In some cases, the radio frequency transmit coil and the at least one gradient coil set are positioned proximate to the concave front surface. In some cases, the radio frequency transmit coil and the at least one gradient coil set are configured to generate an electromagnetic field in a region of interest. In some cases, the region of interest resides outside the concave front surface. In some cases, the system includes a radio frequency receive coil for detecting signal in the region of interest.

[0203] As shown in FIG. 9, the method S200 includes executing a patient positioning protocol comprising running at least one first scan at step S220, running at least one second scan at step S230, reviewing the at least one second scan at step S240, and determining at least one path for conducting a biopsy based on review of the at least one second scan at step S250.

[0204] In some cases, the radio frequency transmit coil and the single-sided gradient coil set are located on the concave front surface. In some cases, the static magnetic field of the permanent magnet ranges from 1 mT to 1 T.

[0205] In some cases, the static magnetic field of the permanent magnet ranges from 10 mT to 195 mT. In some cases, the radio frequency transmit coil comprises a first ring and a second ring that are connected via one or more capacitors and / or one or more rungs. In some cases, the radio frequency transmit coil is non-planar and oriented to partially surround the region of interest. In some cases, the at least one gradient coil set is non-planar, single sided, and oriented to partially surround the region of interest. In some cases, the at least one gradient coil set is configured to project magnetic field gradients in the region of interest.

[0206] In some cases, the at least one gradient coil set comprises one or more first spiral coils at a first position and one or more second spiral coils at a second position, the first position and the second position being located opposite each other about a center region of the at least one gradient coil set. In some cases, the at least one gradient coil set has a rise time less than 10 ps. In some cases, the permanent magnet has an aperture through center of the permanent magnet. In some cases, the system further includes an electromagnet configured to alter the static magnetic field of the permanent magnet within the region of interest. In some cases, the electromagnet has a magnetic field strength from 10 mT to 1 T. In some cases, the radio frequency receive coil is aWSGR Docket No. 49880-720601flexible coil configured to be affixed to an anatomical portion of a patient for imaging within the region of interest. In some cases, the radio frequency receive coil is in one of a single-loop coil configuration, figure-8 coil configuration, or butterfly coil configuration, where the coil is smaller than the region of interest.

[0207] In some cases, the radio frequency transmit coil and the at least one gradient coil set are concentric about the region of interest. In some cases, the magnetic resonance imaging system is a single-sided magnetic resonance imaging system that comprises a magnetic resonance imaging scanner or a magnetic resonance imaging spectrometer.

[0208] FIG. 10 is a flowchart for a method S300 of performing a scan on a magnetic resonance imaging system, according to various embodiments. In some cases, the method S300 includes at step S310 providing a housing having a front surface, a permanent magnet for providing a static magnetic field, a radio frequency transmit coil, and a single-sided gradient coil set. In some cases, the radio frequency transmit coil and the single-sided gradient coil set are positioned proximate to the front surface. In some cases, the method S300 includes providing an electromagnet at step S320. In some cases, the method S300 includes at step S330 activating at least one of the radio frequency transmit coil, the single-sided gradient coil set, or the electromagnet to generate an electromagnetic field in a region of interest. In some cases, the region of interest resides outside the front surface.

[0209] In some cases, the method S300 includes activating a radio frequency receive coil to obtain imaging data at step S340, reconstructing obtained imaging data to produce an output image for analysis at step S350 and displaying the output image for user review and annotation at step S360.

[0210] In some cases, the radio frequency transmit coil and the single-sided gradient coil set are located on the front surface. In some cases, the front surface is a concave surface. In some cases, the permanent magnet has an aperture through the center of the permanent magnet. In some cases, the static magnetic field of the permanent magnet ranges from 1 mT to 1 T. In some cases, the static magnetic field of the permanent magnet ranges from 10 mT to 195 mT.

[0211] In some cases, the radio frequency transmit coil includes a first ring and a second ring that are connected via one or more capacitors and / or one or more rungs. In some cases, the radio frequency transmit coil is non-planar and oriented to partially surround the region of interest. In some cases, the single-sided gradient coil set is non-planar and oriented to partially surround the region of interest. In some cases, the single-sided gradient coil set is configured to project a magnetic field gradient to the region of interest. In some cases, the single-sided gradient coil set includes one or more first spiral coils at a first position and one or more second spiral coils at aWSGR Docket No. 49880-720601second position, the first position and the second position being located opposite each other about a center region of the single-sided gradient coil set. In some cases, the single-sided gradient coil set has a rise time less than 10 ps.

[0212] In some cases, the electromagnet is configured to alter the static magnetic field of the permanent magnet within the region of interest. In some cases, the electromagnet has a magnetic field strength from 10 mT to 1 T. In some cases, the radio frequency receive coil is a flexible coil configured to be affixed to an anatomical portion of a patient for imaging within the region of interest. In some cases, the radio frequency receive coil is in one of a single-loop coil configuration, figure-8 coil configuration, or butterfly coil configuration, wherein the coil is smaller than the region of interest. In some cases, the radio frequency transmit coil and the single-sided gradient coil set are concentric about the region of interest. In some cases, the magnetic resonance imaging system is a single-sided magnetic resonance imaging system that comprises a bore having an opening positioned about a center region of the front surface.

[0213] FIG. 11 is a flowchart for a method S400 of performing a scan on a magnetic resonance imaging system, according to various embodiments. In some cases, the method S400 includes at step S410 providing a housing having a concave front surface, a permanent magnet for providing a static magnetic field, a radio frequency transmit coil, and a single-sided gradient coil set. In some cases, the radio frequency transmit coil and the single-sided gradient coil set are positioned proximate to the front surface.

[0214] In some cases, the method S400 includes at step S420 activating at least one of the radio frequency transmit coil and the at least one gradient coil set to generate an electromagnetic field in a region of interest. In some cases, the region of interest resides outside the concave front surface.

[0215] In some cases, the method S400 includes activating a radio frequency receive coil to obtain imaging data at step S430, reconstructing obtained imaging data to produce an output image for analysis at step S440 and displaying the output image for user review and annotation at step S450.

[0216] In some cases, the radio frequency transmit coil and the single-sided gradient coil set are located on the concave front surface. In some cases, the static magnetic field of the permanent magnet ranges from 1 mT to IT. In some cases, the static magnetic field of the permanent magnet ranges from 10 mT to 195 mT. In some cases, the radio frequency transmit coil comprises a first ring and a second ring that are connected via one or more capacitors and / or one or more rungs. In some cases, the radio frequency transmit coil is non-planar and oriented to partially surround the region of interest. In some cases, the at least one gradient coil set is non-WSGR Docket No. 49880-720601planar, single sided, and oriented to partially surround the region of interest. In some cases, the at least one gradient coil set is configured to project magnetic field gradient in the region of interest.

[0217] In some cases, the at least one gradient coil set comprises one or more first spiral coils at a first position and one or more second spiral coils at a second position, the first position and the second position being located opposite each other about a center region of the at least one gradient coil set. In some cases, the at least one gradient coil set has a rise time less than 10 ps. In some cases, the permanent magnet has an aperture through the center of the permanent magnet. In some cases, the system further includes an electromagnet configured to alter the static magnetic field of the permanent magnet within the region of interest. In some cases, the electromagnet has a magnetic field strength from 10 mT to 1 T. In some cases, the radio frequency receive coil is a flexible coil configured to be affixed to an anatomical portion of a patient for imaging within the region of interest. In some cases, the radio frequency receive coil is in one of a single-loop coil configuration, figure-8 coil configuration, or butterfly coil configuration, where the coil is smaller than the region of interest.

[0218] In some cases, the radio frequency transmit coil and the at least one gradient coil set are concentric about the region of interest. In some cases, the magnetic resonance imaging system is a single-sided magnetic resonance imaging system that comprises a magnetic resonance imaging scanner or a magnetic resonance imaging spectrometer.Pre-Polarizer

[0219] As discussed herein, and in some cases, the various workflows or methods, and various combinations of steps that make up the various workflow or method embodiments, can also include a pre-polarization step.

[0220] In some embodiments, the prepolarizer can be charged by a system power supply. The powering of this polarizer can temporarily change the magnetic field within the field of view either by increasing or decreasing the main magnetic field strength. This change in the magnetic field then creates a change in the total number of nuclear spins that are aligned within the field of view and it changes the time constants by which the nuclear spins relax. An increase in the field allows for more nuclear spins to be aligned with the field, thus temporarily increasing the signal from a given voxel. A decrease in the field changes the relaxation properties of the objects and can allow for increased contrast within the field of view.

[0221] In some cases, the prepolarizer might be first charged to increase the field strength and therefore the signal strength. Then after waiting an appropriate amount of time for the nuclear spins to align (as dictated by the T1 time of the desired spins), the prepolarizer can be removed.WSGR Docket No. 49880-720601As this prepolarizer is depowered, the spins that are aligned will begin to relax and lose energy but can still be imaged by the magnetic resonance system at an increased signal level than when the system did not apply a prepolarizing pulse.Patient Intake

[0222] As discussed herein, and in some cases, the various workflows or methods, and various combinations of steps that make up the various workflow or method embodiments, can also include a patient intake step.

[0223] As part of this step, and any relevant information can be part of the patient intake step, including the intake of all data relevant to the performance of the magnetic resonance system, In some cases herein.

[0224] In some cases, the patient intake step can include, not only data inputted by user, but also data downloaded from any memory source, whether it be, for example, data from a remote data storage component (e.g., the cloud), an on-board data storage component, or portable data storage component (e.g., external flash / solid state drives and external hard drives).

[0225] In some cases, and further related to memory sources, an on-board data storage component (e.g., on board a computing system within an MRI system) can be a random access memory (RAM) or other dynamic memory, or a read only memory (ROM) or other static storage device.

[0226] In some cases, and further related to memory sources, a remote or portable data storage component can include, for example, a magnetic disk, optical disk, solid state drive (SSD), and a media drive and a removable storage interface. A media drive may include a drive or other mechanism to support fixed or removable storage media, such as a hard disk drive, a floppy disk drive, a magnetic tape drive, an optical disk drive, a CD or DVD drive (R or RW), flash drive, or other removable or fixed media drive. As these examples illustrate, the storage media may include a computer-readable storage medium having stored therein particular computer software, instructions, or data.

[0227] In some cases, a storage device may include other similar instrumentalities for allowing computer programs or other instructions or data to be loaded into computing system. Such instrumentalities may include, for example, a removable storage unit and an interface, such as a program cartridge and cartridge interface, a removable memory (for example, a flash memory or other removable memory module) and memory slot, and other removable storage units and interfaces that allow software and data to be transferred from the storage device to computing system.WSGR Docket No. 49880-720601

[0228] In some cases, the data types that can be user inputted, uploaded, downloaded, etc., can include, for example, patient name, patient sex, patient weight, patient height, patient contact information, patient birthdate, patient's referring physician, and patient race. In addition, a clinical baseline can be user inputted that includes information such as the patient's Gleason score for any past biopsies, the frequency of sexual intercourse, the last time the patient had food, and the patient's PSA level.Patient Positioning

[0229] As discussed herein, and in some cases, the various workflows or methods, and various combinations of steps that make up the various workflow or methods, can also include a patient positioning step. The patient positions described below comprise exemplary patient positions. In some cases, a patient may have multiple scans scheduled, such that the patient may be positioned in one manner for one scan (e.g., such as shown in FIGS. 12A-12X) and in another way (e.g., supine or seated) for a pelvic scan.

[0230] As a precursor to the positioning, a patient can undergo a patient preparation and screening process, whereby the patient is screened for foreign bodies and devices such as pacemakers that may represent a contraindication to imaging. The patient's important health conditions, including allergies, as well as patient data received as part of the patient intake process, can also be reviewed.

[0231] For positioning in a full-body MRI, a patient can be placed on a table, such as in a supine position. Receiver imaging coils can be arranged around the body part of interest (e.g., pelvis, head, chest, knee, etc.) If EKG or respiratory gating is required, then these devices are attached at this time. A key anatomic structure such as the bridge of the nose or umbilicus is identified as a landmark using laser guidance, and this is correlated with table position by pressing a button on the gantry.

[0232] In some cases, using the example system illustrated in FIGS. 12A-12X as a basis herein, a patient is positioned in any number of different positions depending on the type of anatomical scan.

[0233] As illustrated in FIG. 12A, when the abdomen is the region scanned, the patient can be laid on a surface at a lateral position. As illustrated, for the abdominal scan, a patient can be positioned to lay sideways facing the bore, with the arm closest to the table stretched out and the other at the side of the body. The abdomen region can be positioned such that it is directly in front of the bore.

[0234] As illustrated in FIG. 12B, when an appendage (e.g., arm or hand) is the region scanned, the patient can be laid on a surface at a supine position. As illustrated, for the appendage scan, aWSGR Docket No. 49880-720601patient can be positioned to be laid down with the arm or hand to be scanned situated directly in front of the bore.

[0235] As illustrated in FIG. 12C, when an appendage (e.g., arm or hand) is the region scanned, the patient can also be placed at a seated position. As illustrated, for the appendage scan, a patient can be positioned to be seated with arm to be scanned raised up against the system such that it is situated directly in front of the bore.

[0236] As illustrated in FIG. 12D, when an appendage (e.g., elbow) is the region scanned, the patient can also be placed at a seated position. As illustrated, for the appendage scan, a patient can be positioned to be seated with elbow to be scanned raised up against the system such that it is situated directly in front of the bore and the other arm resting comfortably.

[0237] As illustrated in FIG. 12E, when an appendage (e.g., knee) is the region scanned, the patient can also be situated to stand with the one leg lifted that is to be scanned. As illustrated, for the appendage scan, a patient can be positioned to be standing and facing the bore such that he leg of interest is lifted with the knee resting directly in front of the bore and the other leg placed firmly on the ground for stability.

[0238] As illustrated in FIG. 12F, when an appendage (e.g., knee) is the region scanned, the patient can also be situated in a lateral position. As illustrated, for the appendage scan, a patient can be positioned to lay sideways facing the bore, with the leg of interest bent and the other leg resting on the table and extended out. The patient's knee can be placed such that it is directly in front of the bore.

[0239] As illustrated in FIG. 12G, when an appendage (e.g., foot) is the region scanned, the patient can also be situated in a lateral position. As illustrated, for the appendage scan, a patient can be positioned to lay sideways facing away from the bore, with the leg of interest bent and resting on the table and the other leg extended out. The patient's foot can be placed such that it is directly in front of the bore.

[0240] As illustrated in FIG. 12H, when an appendage (e.g., foot) is the region scanned, the patient can also be situated in a seated position. As illustrated, for the appendage scan, a patient can be positioned to be seated facing the bore, with the leg of interest extended out toward the bore and the other leg resting comfortably. The patient's foot can be placed such that it is directly in front of the bore.

[0241] As illustrated in FIG. 121, when an appendage (e.g., wrist) is the region scanned, the patient can be situated in a seated position. As illustrated, for the appendage scan, a patient can be positioned to be seated parallel to the system, such that the wrist of interest is directly in front of the bore with and the other arm is resting comfortably to the side.WSGR Docket No. 49880-720601

[0242] As illustrated in FIG. 12J, when the breast is the region scanned, the patient can be laid on a surface in a lateral position. As illustrated, for the breast scan, a patient can be positioned to lay sideways facing the bore, with one arm extended out above the head and the other hand resting to the side of the body. The breast region can be positioned to be directly in front of the bore.

[0243] As illustrated in FIG. 12K, when the breast is the region scanned, the patient can also be placed at a seated position. As illustrated, for the breast scan, a patient can be positioned to be seated and facing the bore such that arms are extended out and resting on the top of the system. The breast region can be positioned to be directly in front of the bore.

[0244] As illustrated in FIG. 12L, when the breast is the region scanned, the patient can also be placed at a kneeling position. As illustrated, for the breast scan, a patient can be positioned to be kneeling and facing the bore such that arms are extended out and resting on the top of the system. The breast region can be positioned to be directly in front of the bore.

[0245] As illustrated in FIG. 12M, when the head is the region scanned, the patient can be laid on a surface at a lateral position. As illustrated, for the head scan, a patient can be positioned to lay sideways facing away from the bore, with the head placed directly in front of the bore.

[0246] As illustrated in FIG. 12N, when the head is the region scanned, the patient can also be laid on a surface at a supine position. As illustrated, for the head scan, a patient can be positioned to lay down face up, with the top of the head against the system, such that it is situated directly in front of the bore.

[0247] As illustrated in FIG. 120, when the heart is the region scanned, the patient can be placed at a seated or standing position. As illustrated, for the heart scan, a patient can be positioned to be seated facing the bore such that the heart region is situated directly in front of the bore.

[0248] As illustrated in FIG. 12P, when the kidney is the region scanned, the patient can be laid on a surface at a lateral position. As illustrated, for the kidney scan, a patient can be positioned to lay sideways facing the bore, with the arm closest to the table stretched out and the other at the side of the body. The kidney region can be positioned such that it is directly in front of the bore.

[0249] As illustrated in FIG. 12Q, when the liver is the region scanned, the patient can be laid on a surface at a lateral position. As illustrated, for the liver scan, a patient can be positioned to lay sideways facing the bore, with the arm closest to the table stretched out or bent to rest the head, and the other at the side of the body. The liver region can be positioned such that it is directly in front of the bore.WSGR Docket No. 49880-720601

[0250] As illustrated in FIG. 12R, when the lung is the region scanned, the patient can be placed at a seated position. As illustrated, for the lung scan, a patient can be positioned to be seated facing away from the bore such that the lung region is situated directly in front of the bore.

[0251] As illustrated in FIG. 12S, when the neck is the region scanned, the patient can be laid on a surface at a lateral position. As illustrated, for the neck scan, a patient can be positioned to lay sideways and face away from the bore. The neck region can be positioned to be directly in front of the bore.

[0252] As illustrated in FIG. 12T, when the pelvis is the region scanned, the patient can be laid on a surface at a lithotomy position. As illustrated, for the pelvic scan, a patient can be positioned to have their back resting on the table and legs raised up to be resting against the top of the system. The pelvic region can be positioned to be directly in front of the bore.

[0253] As illustrated in FIG. 12U, when the pelvis is the region scanned, the patient can also be laid on a surface at a lateral position. As illustrated, for the pelvic scan, a patient can be positioned to lay sideways and face away from the bore. The pelvic region of the body can be positioned to be directly in front of the bore.

[0254] As illustrated in FIG. 12V, when the pelvis is the region scanned, the patient can also be placed at a prone position. As illustrated, for the pelvic scan, a patient can be positioned to rest with the chest against a surface, facing away from the bore. The pelvic region can be positioned such that it is directly in front of the bore.

[0255] As illustrated in FIG. 12W, when the shoulder is the region scanned, the patient can be placed at a seated position. As illustrated, for the shoulder scan, a patient can be positioned to be seated next to the system with the shoulder to be scanned situated directly in front of the bore.

[0256] As illustrated in FIG. 12X, when the spine is the region scanned, the patient can be placed at a seated position. As illustrated, for the spine scan, a patient can be positioned to be seated with back facing away from the bore and spine situated directly in view of the bore.Biopsy Guidance

[0257] As discussed herein, and in some cases, the various workflows or methods, and various combinations of steps that make up the various workflow or method embodiments, can also include biopsy guidance using the disclosed MRI system.

[0258] In some cases, the procedure for biopsy guidance using the disclosed MRI system may include one from the list of medical procedures consisting of transperineal biopsy, transperineal LDR brachytherapy, transperineal HDR brachytherapy, transperineal laser ablation, transperineal cryoablation, transrectal HIFU, breast biopsies, deep brain stimulation (DBS), brain biopsy, liverWSGR Docket No. 49880-720601biopsy, kidney biopsy, lung biopsy, coronary stent insertion, brain stent insertion, and intensity modulated radiation treatment guidance.Calibration

[0259] As discussed herein, and in some cases, the various workflows or methods, and various combinations of steps that make up the various workflow or method embodiments, can also include a calibration step.

[0260] Calibration can take many forms of processes. In some cases, calibration involves running a full scan, similar to the scan run on a patient, in order to ensure image quality. In some cases, after a predetermined period, a user can be prompted to initiate a calibration routine such as, for example, a RF calibration routine. As part of initiating a calibration, a calibration phantom is positioned to allow calibration to advance. A calibration phantom can take many forms. In some cases, a calibration phantom can be an object (such as an artificial object) of known size and composition that is imaged to test, adjust or monitor an MRI systems homogeneity, imaging performance and orientation aspects. A phantom can be a fluid filled container or bottle often filled with a plastic structure of various sizes and shapes.

[0261] RF Calibration routine, in particular, optimizes RF pulse parameters such as, for example, signal power, signal duration and signal bandwidth to ensure image quality. The calibration routine acquires signal data from a calibration phantom using a predetermined set of parameters and sequence. Calibration data can be processed to determine the parameter set that can be used during imaging scans.Computing Systems

[0262] FIG. 14 shows the computer system 1401 comprising a central processing unit (CPU, also “processor” and “computer processor” herein) 1405, which can be a single core or multi core processor, or a plurality of processors for parallel processing. The computer system 1401 also includes memory or memory location (e.g., random-access memory, read-only memory, flash memory), electronic storage unit 1415 (e.g., hard disk), communication interface 1420 (e.g., network adapter) for communicating with one or more other systems, and peripheral devices 1425, such as cache, other memory, data storage and / or electronic display adapters. The memory, storage unit 1415, interface 1420 and peripheral devices 1425 are in communication with the CPU 1405 through a communication bus (solid lines), such as a motherboard. The storage unit 1415 can be a data storage unit (or data repository) for storing data. The computer system 1401 can be operatively coupled to a computer network (“network”) 1430 with the aid of the communication interface 1420. The network 1430 can be the Internet, an internet and / orWSGR Docket No. 49880-720601extranet, or an intranet and / or extranet that is in communication with the Internet. The network 1430 in some cases is a telecommunication and / or data network. The network 1430 can include one or more computer servers, which can enable distributed computing, such as cloud computing. The network 1430, in some cases with the aid of the computer system 1401, can implement a peer-to-peer network, which may enable devices coupled to the computer system 1401 to behave as a client or a server.

[0263] The CPU 1405 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. The instructions can be directed to the CPU 1405, which can subsequently program or otherwise configure the CPU 1405 to implement methods of the present disclosure. Examples of operations performed by the CPU 1405 can include fetch, decode, execute, and writeback.

[0264] The CPU 1405 can be part of a circuit, such as an integrated circuit. One or more other components of the system 1401 can be included in the circuit. In some cases, the circuit is an application specific integrated circuit (ASIC).

[0265] The storage unit 1415 can store files, such as drivers, libraries and saved programs. The storage unit 1415 can store user data, e.g., user preferences and user programs. The computer system 1401 in some cases can include one or more additional data storage units that are external to the computer system 1401, such as located on a remote server that is in communication with the computer system 1401 through an intranet or the Internet.

[0266] The computer system 1401 can communicate with one or more remote computer systems through the network 1430. For instance, the computer system 1401 can communicate with a remote computer system of a user. 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 1401 via the network 1430.

[0267] 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 1401, such as, for example, on the memory 1410 or electronic storage unit 1415. 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 1405. In some cases, the code can be retrieved from the storage unit 1415 and stored on the memory 1410 for ready access by the processor 1405. In some situations, the electronic storage unit 1415 can be precluded, and machine-executable instructions are stored on memory 1410.WSGR Docket No. 49880-720601

[0268] 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.

[0269] Aspects of the systems and methods provided herein, such as the computer system 1401, 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.

[0270] 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 or magnetic 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-readableWSGR Docket No. 49880-720601media 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.

[0271] The computer system 1401 can include or be in communication with an electronic display 1435 that comprises a user interface (UI) 1440 for providing, for example, a UI on a display of the user device. Examples of UI’s include, without limitation, a graphical user interface (GUI) and web-based user interface. In some embodiments, the electronic display may comprise a touch screen.

[0272] 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 1405. The algorithm can, for example, analyze data obtained by the user identification device or the monitoring module (or the medication monitoring module).Definitions

[0273] 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.

[0274] 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 disclosed subranges 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.WSGR Docket No. 49880-720601

[0275] 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 otherwise stated the term “about” meaning within an acceptable error range for the particular value may be assumed.

[0276] 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.

[0277] 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.

[0278] 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.

[0279] As used herein, the terms “treatment” or “treating” are used in reference to a pharmaceutical or other intervention regimen for obtaining beneficial or desired results in theWSGR Docket No. 49880-720601recipient. Beneficial or desired results include but are not limited to a therapeutic benefit and / or a prophylactic benefit. A therapeutic benefit may refer to eradication or amelioration of symptoms or of an underlying disorder being treated. Also, a therapeutic benefit can be achieved with the eradication or amelioration of one or more of the physiological symptoms associated with the underlying disorder such that an improvement is observed in the subject, notwithstanding that the subject may still be afflicted with the underlying disorder. A prophylactic effect includes delaying, preventing, or eliminating the appearance of a disease or condition, delaying or eliminating the onset of symptoms of a disease or condition, slowing, halting, or reversing the progression of a disease or condition, or any combination thereof. For prophylactic benefit, a subject at risk of developing a particular disease, or to a subject reporting one or more of the physiological symptoms of a disease may undergo treatment, even though a diagnosis of this disease may not have been made.

[0280] The section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described.Examples

[0281] Example 1 - Highly Undersampled Projection and Fully Sampled Image Acquisition in Phantom

[0282] To demonstrate the efficacy of the hybrid encoding projection method, an experimental validation was performed using an interventional needle inserted in a tissue-mimicking gel block phantom and a hybrid encoding pulse sequence executed with a Carr-Purcell-Meiboom-Gill (CPMG) acquisition architecture featuring frequency-swept WURST excitation and refocusing pulses. Referring to FIG. 15, an exemplary radial xSPEN pulse sequence diagram is shown illustrating the radial spatiotemporal aspect of the pulse sequence used for encoding in x and y in this exemplary validation. As depicted, the radial spatiotemporal encoding is accomplished by dynamically applying and rotating the x-axis and y-axis gradient pulses. Specifically, the gradients are applied with opposing polarities during the initial two refocusing pulses to generate the quadratic phase profile. The varying x and y gradients shown in different shades of grey in FIG. 15 denote the varying in-plane radial angles corresponding to the distinct readout trajectories (e.g., the radial spokes).

[0283] The experimental setup for the needle verification scan is illustrated in FIG. 16. The validation utilized a standard 13 -gauge magnetic biopsy needle configured to induce a magnetic-field susceptibility change at its tip region. The needle was inserted into a homogeneous gel phantom positioned at the isocenter of the MRI system's field of view (FOV). Signal acquisitionWSGR Docket No. 49880-720601was performed utilizing a specially designed, 2-channel, butterfly style receiver coil oriented perpendicular to the longitudinal z-axis. Identical acquisitions were performed before and after needle insertion, utilizing four, radial spokes for the xSPEN encoding at projection angles of 0, 7i / 4, 7i / 2, and 3TI / 4 with a 20 cm FOV. Fourier encoding was performed using the permanent z gradient of the scanner and 40kHz WURST RF pulses.

[0284] Referring to FIG. 17, difference plots (before and after insertion) of the four spoke signals are shown, illustrating the ID projection data. The system successfully isolated distinct localized signal anomalies (peaks / troughs corresponding to signal hyper- and hypo-intensities induced by the tip of the magnetic needle) along each radial spoke corresponding to the needle intersection. The accompanying table details the precise temporal offsets of these signal peaks and translates them into actual physical spatial offsets relative to the FOV center.

[0285] To demonstrate the efficacy of further embodiments in which hybrid encoded data may be used to generate a full image with or without undersampling, a secondary acquisition was performed consisting of fully-sampled radial, spatial-temporally encoding in the X-Y plane. Referring to FIG. 18, the system mathematically reconstructed the fully sampled projection data into a spatial image, utilizing an inverse Radon model-based reconstruction. The actual physical coordinates of the needle are overlaid on the reconstructed image for ground-truth verification.

[0286] Referring to FIG. 19, the algorithmically predicted locations 502 generated by the system's crossing-point methodology using the undersampled acquisition data are plotted against the actual physical needle position 504. The experimental results confirm high spatial accuracy, demonstrating that the actual needle position lies in tight alignment with the predicted locations 502, yielding a maximum spatial offset of only 2 millimeters.

[0287] FIG. 20A shows plots depicting one-dimensional difference datasets generated from four radial readout trajectories (spokes) between a baseline state and a post-insertion state with the experimental setup depicted in FIG. 19. FIG. 20B shows a table of temporal offsets and spatial distances.

[0288] FIG. 21 shows a reconstructed, multi-dimensional spatial image of the target region overlaid with actual physical needle coordinates generated in phantom using the experimental setup depicted in FIG. 19.

[0289] FIG. 22 shows a spatial coordinate map comparing the algorithmically predicted locations of the interventional device against the actual physical position of the interventional device generated in phantom using the experimental setup depicted in FIG. 19.

[0290] While various 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 wayWSGR Docket No. 49880-720601of 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

WSGR Docket No. 49880-720601CLAIMS WHAT IS CLAIMED IS:

1. A method for three-dimensional localization of an interventional device within a magnetic resonance imaging (MRI) system, the method comprising:a. acquiring a first magnetic resonance (MR) signal dataset of a target region using a hybrid encoding pulse sequence, wherein the hybrid encoding pulse sequence applies spatiotemporal encoding to resolve spatial positions within a first plane and applies Fourier encoding to resolve spatial positions along an axis substantially orthogonal to the first plane;b. acquiring a second MR signal dataset of the target region using the hybrid encoding pulse sequence subsequent to an introduction of the interventional device;c. generating a difference dataset by subtracting the first MR signal dataset from the second MR signal dataset; andd. determining a three-dimensional spatial location of the interventional device within the target region based at least in part on the generated difference dataset.

2. The method of claim 1, wherein the interventional device comprises a dedicated interventional receive coil, and wherein acquiring the first MR signal dataset comprises mathematically initializing a null reference state corresponding to an absence of background anatomical signal, such that the generated difference dataset isolates an active localized signal acquired by the dedicated interventional receive coil during the acquisition of the second MR signal dataset.

3. The method of claim 1 or 2, wherein the spatiotemporal encoding applied in the first plane comprises a cross-term spatiotemporal encoding (xSPEN) sequence, and wherein acquiring the first and second MR signal datasets comprises dynamically modulating magnetic field gradients to acquire a plurality of intersecting readout trajectories.

4. The method of claim 3, wherein determining the three-dimensional spatial location comprises performing a one-dimensional signal processing analysis directly on the plurality of intersecting readout trajectories prior to image reconstruction, identifying a localized signal anomaly along each respective readout trajectory, and calculating a multi-dimensional crossing point of the identified signal anomalies.

5. The method of claim 4, further comprising calculating a Full-Width at Half-Maximum (FWHM) of the localized signal anomaly and validating the localized signal anomaly if the FWHM corresponds to a known physical dimension of the interventional device.WSGR Docket No. 49880-7206016. The method of any one of claims 1 to 5, wherein determining the three-dimensional spatial location comprises mathematically reconstructing the generated difference dataset into a multi-dimensional spatial image and applying a spatial transformation or a second- order derivative analysis to the multi-dimensional spatial image to isolate a linear trajectory of the interventional device.

7. The method of claim 6, wherein applying the second-order derivative analysis comprises computing a Hessian matrix across the multi-dimensional spatial image and isolating voxels satisfying an eigenvalue condition corresponding to a rigid tubular geometric structure.

8. The method of claim 6 or 7, further comprising applying mathematical erosion and dilation operations to the multi-dimensional spatial image to isolate contiguous voxel clusters conforming to a known cylindrical morphology of the interventional device.

9. The method of any one of claims 1 to 8, wherein determining the three-dimensional spatial location comprises applying an iterative reconstruction algorithm to the generated difference dataset, the iterative reconstruction algorithm minimizing an objective function that enforces a sparsity constraint to penalize background artifacts.

10. The method of any one of claims 1 to 9, further comprising iteratively repeating the acquiring, generating, and determining steps to continuously track dynamic movement of the interventional device.

11. The method of claim 10, further comprising calculating a predicted trajectory of the interventional device based on a velocity derived from the continuously tracked dynamic movement.

12. The method of claim 11, further comprising comparing the determined three-dimensional spatial location against the predicted trajectory and automatically triggering a cyberphysical safety intervention if a spatial deviation exceeds a predefined threshold.

13. The method of any one of claims 1 to 12, further comprising receiving extrinsic spatial data from an external tracking module or an interventional robot, and utilizing the extrinsic spatial data to generate a weighted probability map that biases the determination of the three-dimensional spatial location.

14. The method of any one of claims 1 to 13, further comprising outputting a visual representation of the determined three-dimensional spatial location to a display device, wherein the visual representation comprises a subtraction image, a probabilistic heatmap, or a trajectory line plot.WSGR Docket No. 49880-72060115. The method of any one of claims 1 to 14, wherein determining the three-dimensional spatial location comprises processing the generated difference dataset through an artificial neural network trained on a historical dataset of hybrid-encoded MR signals.

16. The method of claim 15, wherein the artificial neural network comprises a convolutional neural network configured to output a voxel-wise probability mask that segments a structural void of the interventional device from background anatomical noise.

17. The method of claim 15 or 16, wherein the artificial neural network is configured as an end-to-end regressor that receives un-reconstructed one-dimensional readout trajectories as input and directly outputs the three-dimensional spatial location of the interventional device.

18. The method of any one of claims 15 to 17, wherein the artificial neural network is trained utilizing a physics-informed loss function configured to mathematically penalize spatial predictions that violate a physical limitation model of the interventional device.

19. The method of any one of claims 1 to 18, wherein the MRI system is a single-sided MRI system comprising an intrinsic, permanent magnetic field gradient extending along the axis substantially orthogonal to the first plane.

20. The method of any one of claims 1 to 19, wherein the MRI system comprises:a. a housing comprising a surface for contact with a subject; andb. a radio frequency receive (RF RX) coil network;wherein the RF RX coil network is configured to enable imaging in a region of interest, wherein the region of interest is external to the surface of the housing by a distance ranging from about 80 mm to about 120 mm.

21. The method of claim 20, wherein the RF RX coil network is configured to fully cover the surface such that there is no access aperture on the surface nearest the region of interest.

22. The method of claim 20 or 21, wherein the RF RX coil network is configured for imaging external to the surface by a distance of about 100 mm.

23. The method of any one of claims 20 to 22, wherein the RF RX coil network comprises a plurality of RF RX coils.

24. The method of any one of claims 20 to 23, wherein the RF RX coil network comprises a plurality of interconnected RF RX coils.

25. The method of any one of claims 20 to 24, wherein the RF RX coil network comprises a plurality of coupled RF RX coils.WSGR Docket No. 49880-72060126. The method of any one of claims 20 to 25, wherein a number of turns and loops of the RF RX coil is configured to be adjustable to cover an entire space between legs of the subject such that the region of interest is entirely or partially covered.

27. The method of any one of claims 20 to 26, wherein the housing further comprises a radio frequency transmit (RF TX) coil proximate to the surface of the housing, wherein the RF TX coil is configured to generate an electromagnetic field in the region of interest.

28. The method of claim 27, wherein the RF TX coil comprises a plurality of figure-8 coils arranged proximal to the surface.

29. The method of claim 27 or 28, wherein the plurality of figure-8 coils are configured to generate a varying magnetic RF field within the region of interest.

30. The method of any one of claims 27 to 29, wherein the plurality of figure-8 coils are orthogonal to each other.

31. The method of any one of claims 27 to 30, wherein the plurality of figure-8 coils are tunable to the same radiofrequency (RF) resonant frequencies.

32. The method of any one of claims 27 to 31, wherein the plurality of figure-8 coils are tunable to different RF resonant frequencies.

33. The method of any one of claims 27 to 32, wherein the plurality of figure-8 coils are configured to generate a uniform magnetic RF field within the region of interest.

34. The method of any one of claims 27 to 33, further comprising an electromagnet configured to generate an electromagnetic field in the region of interest.

35. The method of any one of claims 27 to 34, wherein the housing further comprises a gradient coil set positioned proximate to the surface, wherein the gradient coil set is configured to generate an electromagnetic field in the region of interest.

36. The method of claim 35, wherein the gradient coil set comprises a single-sided gradient coil set.

37. The method of any one of claims 20 to 36, wherein the MRI system is configured to be used for one or more of diagnosis, grading, treatment planning, or monitoring of pelvic conditions.

38. The method of any one of claims 20 to 37, wherein the MRI system comprises a magnetic field strength of less than about 0.5 T.

39. The method of any one of claims 20 to 38, wherein the MRI system comprises one or more of an open or single-sided MRI.

40. The method of any one of claims 20 to 39, wherein the housing comprises a through-bore access aperture.WSGR Docket No. 49880-72060141. The method of any one of claims 20 to 40, wherein the housing does not comprise a through-bore access aperture.

42. The method of any one of claims 20 to 41, wherein the MRI system is configured to be used in an office setting without shielding or floor reinforcements.

43. The method of any one of claims 20 to 42, wherein the MRI system comprises at least one permanent magnet configured for use without superconducting material.

44. The method of any one of claims 20 to 43, wherein the RF RX coil is configured to capture images of the subject when the subject is in a position in front of or on top of the MRI, wherein the position is a high lithotomy, an inclined lithotomy, or a seated position over the MRI.

45. The method of claim 44, wherein the RF RX coil is configured to capture images of the subject when the subject is in contact with the surface of the MRI in the high lithotomy, the inclined lithotomy, or the seated position.

46. The method of claim 44 or 45, wherein the housing is configured to be positioned such that a central axis thereof is perpendicular to a floor when capturing images of the subject in the high lithotomy or the inclined lithotomy.

47. The method of claim 45 or 46, wherein the housing is configured to be positioned such that a central axis thereof is parallel to a floor when capturing images of the subject in the seated position.

48. The method of any one of claims 44 to 47, wherein the MRI system is configured to be usable in a first mode and a second mode, wherein the first mode comprises capturing images of the subject in the high lithotomy or the inclined lithotomy when the housing is positioned such that a central axis thereof is perpendicular to a floor, and wherein the second mode comprises capturing images of the subject in the seated position when the housing is positioned such that a central axis thereof is parallel to the floor.

49. A system for three-dimensional localization of an interventional device, the system comprising:a. a magnetic resonance imaging (MRI) system;b. one or more processors;c. one or more non-transitory computer-readable storage media storing instructions that, when executed by the at least one processor, cause the system to: i. acquire, via the MRI system, a first magnetic resonance (MR) signal dataset of a target region using a hybrid encoding pulse sequence, wherein the hybrid encoding pulse sequence is configured to apply spatiotemporalWSGR Docket No. 49880-720601encoding to resolve spatial positions within a first plane and is configured to apply Fourier encoding to resolve spatial positions along an axis substantially orthogonal to the first plane;ii. acquire, via the MRI system, a second MR signal dataset of the target region using the hybrid encoding pulse sequence subsequent to an introduction of the interventional device;iii. generate a difference dataset by subtracting the first MR signal dataset from the second MR signal dataset; andiv. determine a three-dimensional spatial location of the interventional device within the target region based at least in part on the generated difference dataset.

50. The system of claim 49, wherein the interventional device comprises a dedicated interventional receive coil, and wherein acquiring the first MR signal dataset comprises mathematically initializing a null reference state corresponding to an absence of background anatomical signal, such that the generated difference dataset isolates an active localized signal acquired by the dedicated interventional receive coil during the acquisition of the second MR signal dataset.

51. The system of claim 49 or 50, wherein the spatiotemporal encoding applied in the first plane comprises a cross-term spatiotemporal encoding (xSPEN) sequence, and wherein acquiring the first and second MR signal datasets comprises dynamically modulating magnetic field gradients to acquire a plurality of intersecting readout trajectories.

52. The system of claim 51, wherein determining the three-dimensional spatial location comprises performing a one-dimensional signal processing analysis directly on the plurality of intersecting readout trajectories prior to image reconstruction, identifying a localized signal anomaly along each respective readout trajectory, and calculating a multi-dimensional crossing point of the identified signal anomalies.

53. The system of claim 52, wherein the instructions are further configured to cause the system to calculate a Full-Width at Half-Maximum (FWHM) of the localized signal anomaly and validate the localized signal anomaly if the FWHM corresponds to a known physical dimension of the interventional device.

54. The system of any one of claims 49 to 53, wherein determining the three-dimensional spatial location comprises mathematically reconstructing the generated difference dataset into a multi-dimensional spatial image and applying a spatial transformation or a second-WSGR Docket No. 49880-720601order derivative analysis to the multi-dimensional spatial image to isolate a linear trajectory of the interventional device.

55. The system of claim 54, wherein applying the second-order derivative analysis comprises computing a Hessian matrix across the multi-dimensional spatial image and isolating voxels satisfying an eigenvalue condition corresponding to a rigid tubular geometric structure.

56. The system of claim 54 or 55, wherein the instructions are further configured to cause the system to apply mathematical erosion and dilation operations to the multi-dimensional spatial image to isolate contiguous voxel clusters conforming to a known cylindrical morphology of the interventional device.

57. The system of any one of claims 49 to 56, wherein determining the three-dimensional spatial location comprises applying an iterative reconstruction algorithm to the generated difference dataset, the iterative reconstruction algorithm minimizing an objective function that enforces a sparsity constraint to penalize background artifacts.

58. The system of any one of claims 49 to 57, wherein the instructions are further configured to cause the system to iteratively repeat the acquiring, generating, and determining steps to continuously track dynamic movement of the interventional device.

59. The system of claim 58, wherein the instructions are further configured to cause the system to calculate a predicted trajectory of the interventional device based on a velocity derived from the continuously tracked dynamic movement.

60. The system of claim 59, wherein the instructions are further configured to cause the system to compare the determined three-dimensional spatial location against the predicted trajectory and automatically trigger a cyber-physical safety intervention if a spatial deviation exceeds a predefined threshold.

61. The system of any one of claims 49 to 60, wherein the instructions are further configured to cause the system to receive extrinsic spatial data from an external tracking module or an interventional robot and utilize the extrinsic spatial data to generate a weighted probability map that biases the determination of the three-dimensional spatial location.

62. The system of any one of claims 49 to 61, wherein the instructions are further configured to cause the system to output a visual representation of the determined three-dimensional spatial location to a display device, wherein the visual representation comprises a subtraction image, a probabilistic heatmap, or a trajectory line plot.WSGR Docket No. 49880-72060163. The system of any one of claims 49 to 62, wherein determining the three-dimensional spatial location comprises processing the generated difference dataset through an artificial neural network trained on a historical dataset of hybrid-encoded MR signals.

64. The system of claim 63, wherein the artificial neural network comprises a convolutional neural network configured to output a voxel-wise probability mask that segments a structural void of the interventional device from background anatomical noise.

65. The system of claim 63 or 64, wherein the artificial neural network is configured as an end-to-end regressor that receives un-reconstructed one-dimensional readout trajectories as input and directly outputs the three-dimensional spatial location of the interventional device.

66. The system of any one of claims 63 to 65, wherein the artificial neural network is trained utilizing a physics-informed loss function configured to mathematically penalize spatial predictions that violate a physical limitation model of the interventional device.

67. The system of any one of claims 49 to 66, wherein the MRI system is a single-sided MRI system comprising an intrinsic, permanent magnetic field gradient extending along the axis substantially orthogonal to the first plane.

Images