Medical systems, devices, and kits useful in performing treatment under magnetic resonance imaging, and related methods

Abstract

An exemplary medical system, as well as associated devices, kits, and methods useful in performing treatments under magnetic resonance imaging, is described. The exemplary medical system includes a first medical device and a second medical device. The first medical device has a first passive marker. The first passive marker is formed of a first material having a first magnetic susceptibility. The second medical device has a second passive marker. The second passive marker is formed of a second material having a second magnetic susceptibility. The second passive marker produces an image artifact under MRI. The image artifact produced by the second passive marker is altered when the first passive marker overlaps the second passive marker under MRI.

Description

[Technical field]

[0001] The present disclosure generally relates to the field of medical devices. More particularly, the present disclosure relates to a medical system useful for performing a treatment under magnetic resonance imaging (MRI), a medical device useful for performing a treatment under MRI, a kit useful for performing a treatment under MRI, and a method for performing a treatment under MRI. [Background technology]

[0002] The field of interventional MRI has gained widespread acceptance and has seen an increase in the number of procedures that can be performed. Interventional procedures performed under MRI have several advantages over X-ray guided interventions. For example, patients are not exposed to ionizing radiation. MRI also offers the ability to characterize tissue and functional blood flow during interventional procedures.

[0003] The development of interventional procedures performed under MRI has been limited by the unavailability of tools required to perform these procedures. Thus, patients are required to make multiple visits to treatment facilities for visualization, diagnosis, and treatment of various conditions. In addition, multiple imaging modalities are often required, which affects the accuracy of using magnetic resonance (MR) images in prescribing interventions. For example, interventional medical devices with high magnetic susceptibility placed in the magnetic field generated by an MR scanner tend to interact with and / or distort the applied external magnetic field. As a result, these devices can produce large image artifacts that can obliterate key features in the targeted anatomical structures and can harm the scanned patient due to the forces and torques induced by this interaction. Alternatively, interventional medical devices with low magnetic susceptibility placed in the magnetic field generated by an MR scanner can make the device nearly invisible under MRI, making identification, tracking, and navigation of the device nearly impossible during interventional procedures.

[0004] To overcome these problems, conventional MRI-compatible devices have adopted various visualization techniques, including passive susceptibility-based markers, semi-active resonant circuits, and active antenna coils. Naturally, passive susceptibility-based markers are the least complex to design and fabricate, since they do not require electrical circuit design and integration, or high-frequency operation. However, conventional passive susceptibility-based markers are usually tailored for a specific device and fixed in a specific configuration on the device or component, which creates unalterable image artifacts when performing a procedure under MRI.

[0005] Thus, there is a need for new and improved medical systems useful in performing MRI-guided therapy, medical devices useful in performing MRI-guided therapy, kits useful in performing MRI-guided therapy, and methods of performing MRI-guided therapy. Summary of the Invention [Problem to be solved by the invention]

[0006] Described herein are various exemplary medical systems useful in performing MRI-guided procedures, medical devices useful in performing MRI-guided procedures, kits useful in performing MRI-guided procedures, and methods of performing MRI-guided procedures. [Means for solving the problem]

[0007] An exemplary medical system useful in performing treatment under MRI includes a first medical device and a second medical device. The first medical device has a first passive marker. The first passive marker is formed of a first material having a first magnetic susceptibility. The second medical device has a second passive marker. The second passive marker is formed of a second material having a second magnetic susceptibility. The second passive marker produces an image artifact under MRI. The image artifact produced by the second passive marker is altered when the first passive marker overlaps the second passive marker under MRI.

[0008] An exemplary kit useful in performing a treatment under MRI includes a medical system including a first medical device and a second medical device. The first medical device has a first passive marker. The first passive marker is formed of a first material having a first magnetic susceptibility. The second medical device has a second passive marker. The second passive marker is formed of a second material having a second magnetic susceptibility. The second passive marker produces an image artifact under MRI. The image artifact produced by the second passive marker is altered when the first passive marker overlaps the second passive marker under MRI.

[0009] An exemplary method of performing a treatment under MRI includes placing a patient in a magnetic resonance scanner, scanning a first portion of the patient using the magnetic resonance scanner, the magnetic resonance scanner having a first set of MR imaging parameters, acquiring a magnetic resonance image of the first portion of the patient, identifying tissue having a predefined characteristic using the magnetic resonance image, selecting a procedure to treat the tissue based on the predefined characteristic, selecting a medical system having a first medical device and a second medical device to effect performance of the procedure, and, while the patient is still placed in the magnetic resonance scanner used to scan the first portion of the patient, scanning a second portion of the patient using the magnetic resonance scanner that includes image artifacts caused by markers placed on the medical system and the second medical device, the medical system being moved into the body passageway and to the tissue. the first medical device relative to the second medical device to modify the image artifacts caused by the markers; scanning a third portion of the patient including the medical system and the modified image artifacts using a magnetic resonance scanner; acquiring a magnetic resonance image of the third portion of the patient including the medical system and the modified image artifacts; modifying the first set of MR image parameters to a second set of MR image parameters based on the modified image artifacts; and performing a treatment.

[0010] These exemplary medical systems, devices, kits, and methods can be further understood upon consideration of the following detailed description and accompanying drawings. [Brief description of the drawings]

[0011] [Figure 1]FIG. 1 is a partial elevational view of a first exemplary medical system including a first exemplary medical device and a second exemplary medical device. [Diagram 2] 2 is an elevational view of a first exemplary medical device included in the medical system shown in FIG. 1. [Diagram 3] 2 is an elevational view of a second exemplary medical device included in the medical system shown in FIG. 1. [Figure 4] FIG. 3 is an enlarged view of area A in FIG. [Diagram 5] FIG. 4 is an enlarged view of area B in FIG. [Figure 6] FIG. 2 is an exploded elevational view of a second exemplary medical system including a first exemplary medical device and a second exemplary medical device. [Figure 7] FIG. 13 is an exploded elevational view of a third exemplary medical system including a first exemplary medical device and a second exemplary medical device. [Figure 8] 1 illustrates an exemplary kit comprising an exemplary medical system useful in performing a procedure under MRI. [Figure 9] 11 is a partial perspective view of a fourth exemplary medical system including a first exemplary medical device, a second exemplary medical device, a third exemplary medical device, and a fourth exemplary medical device. [Figure 10] 10 is a cross-sectional view of the fourth exemplary medical system shown in FIG. 9 taken along line 10-10. [Figure 11] FIG. 1 is a schematic diagram of an exemplary method for performing a treatment under MRI. [Figure 12] 1 is an MR image showing a first medical device of a medical system disposed within a body passageway, the first medical device comprising a first plurality of markers, each of which produces an image artifact under MRI. [Figure 13]1 is an MR image showing a medical system disposed within a body passageway, the medical system comprising a first medical device and a second medical device, the first medical device comprising a first plurality of markers and the second medical device comprising a second plurality of markers, the first and second plurality of markers being arranged in an overlapping configuration to modify (e.g., amplify, attenuate, eliminate) image artifacts caused by the first plurality of markers under MRI. [Figure 14] 1 is an MR image showing a medical system disposed within a body passageway, the medical system comprising a first medical device and a second medical device, the first medical device comprising a first plurality of markers and the second medical device comprising a second plurality of markers, the overlapping configuration of the first and second plurality of markers altering (e.g., amplifying) image artifacts caused by the first plurality of markers under MRI. [Figure 15] 1 is an MR image showing a medical system disposed within a body passageway, the medical system comprising a first medical device and a second medical device, the first medical device comprising a first plurality of markers and the second medical device comprising a second plurality of markers, an overlapping configuration of the markers of the first plurality of markers and the markers of the second plurality of markers modifying (e.g., amplifying, attenuating, eliminating) image artifacts caused by the markers of the first plurality of markers under MRI. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The following detailed description and accompanying drawings describe and illustrate various exemplary medical systems useful in performing treatment under MRI, medical devices useful in performing treatment under MRI, kits useful in performing treatment under MRI, and methods of performing treatment under MRI. The descriptions and illustrations of these examples are provided to enable one skilled in the art to make and use the medical systems, devices, kits, and methods of performing treatment under MRI. These descriptions and illustrations are not intended to limit in any manner the scope of the invention or the protection sought. The invention can be practiced or performed in various ways, and the examples described and illustrated herein are merely selected examples of various ways to practice or perform the invention and are not to be considered exhaustive.

[0013] As used herein, the term "attached" refers to one member being fixed to another member such that the members do not completely separate from one another when used in accordance with the intended use of the item that includes the member in the attached configuration.

[0014] As used herein, the term "circumference" refers to a boundary that surrounds the exterior or interior of a body, element, or feature and does not impart any structural organization to the body, element, or feature.

[0015] As used herein, the term "marker" refers to a first material discretely deposited on a second material such that the first material is visible under MRI and distinguishable from the second material under MRI, a portion of an interventional device in which the first material is incorporated into a second material such that the combination of the first and second materials is visible under MRI and distinguishable from the second material under MRI, and / or a portion of an interventional device in which the material forming the portion of the interventional device has been manipulated such that the portion is visible under MRI and distinguishable from the remainder of the interventional device under MRI.

[0016] As used herein, the term "passive" in relation to a marker refers to a marker that is not powered or is powered only by the electromagnetic field of the MR scanner.

[0017] As used herein, the term "treatment" refers to a medical procedure performed on or at a portion of a patient's body. Examples of treatments include delivery of a drug to a site within a body vessel, altering the local environment within a body vessel, such as by heating or cooling, and removal of tissue or a portion of tissue from a site within a patient's body (i.e., a biopsy).

[0018] As used herein, the term "magnetic susceptibility" refers to an intrinsic property of a material related to how much it becomes magnetized in an applied magnetic field.

[0019] As used herein, the term "susceptibility," which does not include "magnetic," refers to the ability of an element to affect an external magnetic field. Susceptibility depends on various properties of the element, including its size, density, volume, geometric configuration, and other physical properties, as well as the magnetic susceptibility of the material from which the element is formed.

[0020] 1, 2, 3, 4, and 5 show a first exemplary medical system 8 useful in performing a procedure under MRI. In this example, the first exemplary medical system 8 comprises a first medical device 10 and a second medical device 50.

[0021] In the illustrated embodiment, the first medical device 10 is a cannula 12 and the second medical device 50 is a stylet 52 that may be used coaxially with the first medical device 10 .

[0022] Cannula 12 has a longitudinal axis 13, a hub member 14, and an elongate member 16. Hub member 14 has a proximal end 18, a distal end 20, and a body 22 defining a lumen 24 and protrusions 26. Hub member 14 provides a mechanism for attaching other devices (e.g., a second medical device 50) to cannula 12. Lumen 24 extends from proximal end 18 to distal end 20 such that one or more devices can be passed through and within hub member 14. Elongate member 16 has a proximal end 30, a distal end 32, a length 31, an inner diameter 33, an outer surface 34, an inner surface 36, and a body 38 defining a lumen 40 and a tapered distal tip 42 having a cutting edge 44. Lumen 40 extends from proximal end 30 to distal end 32 to allow one or more devices to pass through and within elongate member 16 of cannula 12. In the illustrated embodiment, elongate member 16 of cannula 12 is formed of a first material having a first magnetic susceptibility.

[0023] The elongate member 16 of the cannula 12 includes a first marker 46 disposed between the proximal and distal ends 30, 32 of the elongate member 16 of the cannula 12 and around the entire circumference of the body 38 of the elongate member 16. The first marker 46 is a passive marker and is formed of a second material (e.g., pure titanium) different from the first material. The second material has a second magnetic susceptibility different from the first magnetic susceptibility and produces an image artifact under MRI having a first set of characteristics (e.g., size, shape, position, orientation, magnetic susceptibility, strength).

[0024] The stylet 52 has a hub member 54 and an elongate member 56. The hub member 54 has a proximal end 58, a distal end 60, and a body 62 defining a recess 64. The hub member 54 provides a mechanism for attaching another device (e.g., the first medical device 10) to the stylet 52. The recess 64 extends into the body 62 from a location between the proximal end 58 and the distal end 60 toward the proximal end 58. The recess 64 is sized to receive the protrusion 26 defined by the hub member 14 of the cannula 12 such that a releasable attachment between the cannula 12 and the stylet 52 may be accomplished. The elongate member 56 has a proximal end 66, a distal end 68, a length 67, an outer diameter 69, an outer surface 70, and a body 72 defining a solid member having a tapered distal tip 74 having a cutting edge 76. The length 67 of the elongate member 56 of the stylet 52 is greater than the length 31 of the elongate member 16 of the cannula 12. The outer diameter 69 of the elongate member 56 of the stylet 52 is less than the inner diameter 33 of the elongate member 16 of the cannula 12. This structural configuration allows the elongate member 56 of the stylet 52 to pass through and through the lumen 24 of the hub member 14 and the lumen 40 of the elongate member 16 of the cannula 12, as shown in FIG. 1. The elongate member 56 of the stylet 52 is formed of a third material having a third magnetic susceptibility. In the illustrated embodiment, the first material forming the elongate member 16 of the cannula 12 and the third material forming the elongate member 56 of the stylet 52 are the same.

[0025] In the illustrated embodiment, the elongate member 56 of the stylet 52 includes a second marker 78 disposed between the proximal end 66 and the distal end 68 of the elongate member 56 of the stylet 52 and around the entire circumference of the body 62. The second marker 78 is a passive marker and is formed of a fourth material (e.g., polycrystalline graphite) different from the first and third materials and having a fourth magnetic susceptibility different from (e.g., greater than, less than, or opposite to) the first and third magnetic susceptibilities. The second marker 78 produces an image artifact under MRI having a second set of properties (e.g., size, shape, location, orientation, magnetic susceptibility, strength) different from the first set of properties. The second marker 78 is positioned on the elongate member 56 such that the first marker 46 can overlap the second marker 78 when the first medical device 10 and the second medical device 50 are used in combination. For example, as shown in FIG. 1, when the second medical device 50 is placed within the first medical device 10 and the first marker 46 and the second marker 78 are positioned at the same position along the longitudinal axis 13 of the elongate member 16 of the cannula 12 (e.g., axially), the first marker 46 and the second marker 78 overlap.

[0026] In the illustrated embodiment, each of the markers 46, 78 is a band of material attached to a respective elongate member 16, 56. Each of the first and third materials is a material that is not susceptible to magnetism or has a low magnetic susceptibility relative to the magnetic susceptibility of the material forming the marker included in the medical device (e.g., a paramagnetic, non-ferromagnetic, non-diamagnetic material), and the material used to form the marker included in the medical device is a material that is susceptible to magnetism or has a high magnetic susceptibility relative to the magnetic susceptibility of the material forming another portion of the medical device (e.g., the elongate member) (e.g., a paramagnetic, ferromagnetic, non-diamagnetic material), or has a low magnetic susceptibility relative to the magnetic susceptibility of the material forming the marker and / or another portion of the medical device (e.g., the elongate member).

[0027] The first material forming the elongate member 16 of the first medical device 10, the second material forming the elongate member 56 of the second medical device 50, and the material forming the markers included in the medical devices may include any suitable material having a magnetic susceptibility as described herein. For example, the first material, the second material, the third material, and the fourth material may include any suitable MRI compatible material having a magnetic susceptibility as described herein. In the illustrated embodiment, the first material and the third material each include titanium, and the first marker 46 is formed of a second material having a second magnetic susceptibility that modifies the image artifacts caused by the second marker 78 under MRI when the first marker 46 overlaps (e.g., axially) with the second marker 78. Alternatively, the second marker may be formed of a fourth material having a fourth magnetic susceptibility that modifies the image artifacts caused by the first marker under MRI when the first marker overlaps (e.g., axially) with the second marker in use. These alternatives may be accomplished by forming the first marker and the second marker from the same or different materials or materials having different magnetic susceptibilities. If formed from the same material, the second magnetic susceptibility or second susceptibility may be the same or different from the fourth magnetic susceptibility or fourth susceptibility depending on various considerations such as how the material is applied to the medical device. If formed from different materials, the second magnetic susceptibility or second susceptibility may be the same or different from the fourth magnetic susceptibility or fourth susceptibility depending on various considerations such as how the material is applied to the medical device.

[0028] For example, using the principle of passive susceptibility-based marker superposition (i.e., the property that magnetic field distortions due to marker overlap are additive or subtractive), a first medical device 10 and a second medical device 50, each having its own marker 46, 78, can be used to modify one or more image artifacts caused under MRI when the medical devices 10, 50 are used in combination. For example, when the first medical device 10 and the second medical device 50 are used such that the first marker 46 overlaps (e.g., axially) the second marker 78, the image artifacts caused under MRI by the second marker 78 can be attenuated by the first marker 46 or can be completely or partially eliminated, or vice versa. In this embodiment, the first marker 46 has an equal but opposite magnetic susceptibility (e.g., opposite sign, opposite magnetic susceptibility) to the second marker 78. However, alternative embodiments can include a first marker having a magnetic susceptibility that is not equal to and opposite to that of the second marker. Alternatively, when the first medical device 10 and the second medical device 50 are used such that the first marker 46 overlaps the second marker 78, the image artifacts caused under MRI by the second marker 78 may be amplified by the first marker 46, or vice versa. In this embodiment, the first marker 46 has the same magnetic susceptibility (e.g., same sign, equal magnetic susceptibility, unequal magnetic susceptibility) or the same susceptibility or greater than the second marker 78. When the first and second markers overlap, altered image artifacts are caused under MRI having a third set of properties (e.g., size, shape, position, orientation, magnetic susceptibility, strength) that are different from the first and second sets of properties.

[0029] Using the medical system 8 and the first and second medical devices 10 and 50 in this manner is believed to be advantageous at least because image artifacts generated under MRI can be dynamically altered in real time during the performance of an MRI-guided procedure, or across multiple MRI-guided procedures, as described herein. For example, a dynamic range of image artifacts can be generated under MRI by changing the relative positions of the first and second medical devices 10 and 50 in real time. For example, a first marker on the first medical device and a second marker on the second medical device can act independently (e.g., when not overlapping) or collectively (e.g., when overlapping) against an external magnetic field depending on their location relative to each other, so as to generate various distinguishable image artifacts under MRI. Alternatively, the first and second medical devices may be attached to or positioned relative to each other such that, during performance of an MRI-guided procedure, or across multiple MRI-guided procedures, image artifacts produced under MRI by a marker on one of the first and second medical devices are statically altered (e.g., by another marker, by another medical device).

[0030] By taking advantage of the paramagnetic, ferromagnetic, and diamagnetic properties of materials, clinicians can amplify, attenuate, or substantially eliminate all or most of the image artifacts near the region of interest. For example, when obtaining a prostate biopsy, it may be desirable to have no or nearly no image artifacts at or near the tip of a cannula (e.g., a needle cannula), such as one formed of titanium. Thus, a first medical device may be formed of titanium, and a second medical device, or a portion of the second medical device (e.g., a distal end portion, a marker), may be formed of a material (e.g., polycrystalline graphite) that eliminates or attenuates image artifacts produced by the first medical device during use. Pure titanium has a magnetic susceptibility of about 160 ppm, and polycrystalline graphite has a magnetic susceptibility of about 200 ppm. By using these materials concentrically, any susceptibility effects are largely cancelled out, resulting in no or nearly no image artifacts under MRI.

[0031] Although the first medical device 10 has been shown as including one marker 46 located at a particular location on the first medical device 10 and the second medical device 50 has been shown as including one marker 78 located at a particular location on the second medical device 50, any suitable number of markers may be located at any suitable location on the medical device according to one embodiment. Examples of suitable numbers of markers to include on a medical device according to one embodiment include one marker, two markers, three or more markers, three markers, multiple markers, four markers, five markers, six markers, seven markers, eight markers, nine markers, ten markers, and eleven or more markers. Additionally, in medical devices including two or more markers, the markers may be spaced apart from one another by any desired distance (e.g., equally spaced or with varying distances between adjacent markers). However, it should be noted that since markers produce visual artifacts and their usefulness in a medical device is based on the production of this visual artifact in an MR procedure, it is desirable to space the markers on a single medical device at a distance from each other such that the visual artifacts produced by the medical devices do not overlap or come close to overlapping. However, alternative embodiments can include a first medical device in which a material forming part or all of the elongate member of the first medical device can be utilized as a marker to modify the image artifacts of a second medical device placed through the first medical device, as described herein. Alternatively, alternative embodiments can include a second medical device in which a material forming part or all of the elongate member of the second medical device can be utilized as a marker to modify the image artifacts of a first medical device through which the second medical device may be placed, as described herein.

[0032] Although the elongate member 16 of the cannula 12 has been shown as including a tapered distal tip 42 having a cutting edge 44, and the elongate member 56 of the stylet 52 has been shown as including a tapered distal tip 74 having a cutting edge 76, the elongate members included in the medical device may include any suitable structural configuration, such as having a blunt or non-tapered distal tip. Additionally, in alternative embodiments, the hub member may include any suitable structure for effecting attachment to another device, the hub member may be omitted from the medical device, and / or the stylet may be hollow to define a lumen extending the entire length of the stylet or a portion of the length of the stylet.

[0033] 6 illustrates a second exemplary medical system 108 useful in performing a treatment under MRI (e.g., altering an image artifact under MRI, altering a characteristic of an image artifact under MRI). In this example, the second exemplary medical system 108 includes a first medical device 110 and a second medical device 150. In the illustrated embodiment, the first medical device 110 is a cannula 112 and the second medical device 150 is a stylet 152 that may be used coaxially with the first medical device 110. The cannula 112 is similar to the cannula 12 illustrated in FIGS. 1, 2, and 4 and described above, except as described in more detail below. The stylet 152 is similar to the stylet 52 illustrated in FIGS. 1, 3, and 5 and described above, except as described in more detail below.

[0034] In the illustrated embodiment, the cannula 112 has a longitudinal axis 113, a hub member 114, and an elongate member 116. The elongate member 116 has a proximal end 130, a distal end 132, an outer surface 134, an inner surface 136, and a body 138 defining a lumen 140. The lumen 140 extends from the proximal end 130 to the distal end 132 such that one or more devices can be passed through and within the elongate member 116 of the cannula 112. The elongate member 116 of the cannula 112 is formed of a first material having a first magnetic susceptibility.

[0035] In the illustrated embodiment, the elongate member 116 of the cannula 112 comprises a first plurality of markers 146 disposed between the proximal end 130 and the distal end 132 of the elongate member 116. Each marker of the first plurality of markers 146 is disposed around only a portion of the circumference of the body 138 of the elongate member 116 of the cannula 112. Each marker in the first plurality of markers 146 is equally spaced along the elongate member 116 from adjacent markers in the first plurality of markers 146. Each marker in the first plurality of markers 146 is a passive marker and is formed of a second material different from the first material. The second material has a second magnetic susceptibility different from (e.g., greater than) the first magnetic susceptibility. Each marker in the first plurality of markers 146 produces an image artifact under MRI having a first set of characteristics (e.g., size, shape, position, orientation, magnetic susceptibility, strength).

[0036] In the illustrated embodiment, the stylet 152 has a hub member 154 and an elongate member 156. The elongate member 156 has a proximal end 166, a distal end 168, an outer surface 170, and a body 172 defining a solid member. The elongate member 156 of the stylet 152 can be passed through and through the lumen 140 of the elongate member 116 of the cannula 112. The elongate member 156 of the stylet 152 is formed of a third material having a third magnetic susceptibility. In the illustrated embodiment, the first material forming the elongate member 116 of the cannula 112 and the third material forming the elongate member 156 of the stylet 152 are different (e.g., have different magnetic susceptibilities).

[0037] In the illustrated embodiment, the elongate member 156 of the stylet 152 includes a second plurality of markers 178 disposed between the proximal end 166 and the distal end 168. Each marker of the second plurality of markers 178 is disposed around only a portion of the circumference of the body 172 of the elongate member 156 of the stylet 152. Each marker in the second plurality of markers 178 is equally spaced along the elongate member 156 from adjacent markers in the second plurality of markers 178. Each marker in the second plurality of markers 178 is a passive marker and is formed of a fourth material different from the first and third materials and having a fourth magnetic susceptibility different from (e.g., greater than) the first and third magnetic susceptibilities. Each marker in the second plurality of markers 178 produces an image artifact under MRI having a second set of characteristics (e.g., size, shape, position, orientation, magnetic susceptibility, intensity) that differs from the first set of characteristics. Each marker in the second plurality of markers 178 is positioned on the elongate member 156 such that when the second medical device 150 is positioned within the first medical device 110, each marker in the first plurality of markers 146 may overlap (e.g., axially) with a marker in the second plurality of markers 178 (e.g., each marker in the first plurality of markers 146 is co-located with a marker in the second plurality of markers 146 along the longitudinal axis 113 of the elongate member 116 of the cannula 112).

[0038] In the illustrated embodiment, each marker in the first plurality of markers 146 and each marker in the second plurality of markers 178 are depositions of material attached to the respective elongate members 116, 156 and are formed as dots. The first material forming the elongate member 116 of the first medical device 110, the second material forming the elongate member 156 of the second medical device 150, and the material forming the markers included in the medical devices may include any suitable material having a magnetic susceptibility as described herein. For example, the first material, second material, third material, and fourth material may include any suitable MRI compatible material having a magnetic susceptibility as described herein. In the illustrated embodiment, the first material includes titanium and the second material includes a polymer, and each marker in the first plurality of markers 146 is formed of a second material having a second magnetic susceptibility that modifies image artifacts produced under MRI by each marker in the second plurality of markers 178 when a marker in the first plurality of markers 146 overlaps a marker in the second plurality of markers 178. When the first plurality of markers 146 and the second plurality of markers overlap, a plurality of modified image artifacts are produced under MRI having a third set of properties (e.g., size, shape, position, orientation, magnetic susceptibility, strength) that differ from the first and second sets of properties. Alternatively, each marker in the second plurality of markers may be formed of a fourth material having a fourth magnetic susceptibility that modifies image artifacts produced under MRI by each marker in the first plurality of markers when, in use, a marker in the first plurality of markers overlaps a marker in the second plurality of markers. In the illustrated embodiment, this is accomplished by forming each marker in the first plurality of markers 146 from a material different from the material forming each marker in the second plurality of markers 178, such that the second material has a second magnetic susceptibility different from the fourth magnetic susceptibility (e.g., the magnetic susceptibility has a different sign). In this embodiment, when first medical device 110 and second medical device 150 are used such that first plurality of markers 146 overlaps second plurality of markers 178, image artifacts caused under MRI by markers in second plurality of markers 178 are attenuated by markers in first plurality of markers 146, or vice versa.Alternative embodiments may include a first plurality of markers formed of a second material having a second magnetic susceptibility or second susceptibility that is the same or different from a fourth magnetic susceptibility or fourth susceptibility of the fourth material forming the second plurality of markers, such that the magnetic susceptibility or susceptibility of the second material and / or fourth material is amplified (e.g., the magnetic susceptibility has the same sign), attenuated or eliminated and resulting image artifacts under MRI are amplified, attenuated or eliminated.

[0039] The use of medical system 108 and first and second medical devices 110, 150 may be advantageous at least because image artifacts caused by first plurality of markers 146 and / or second plurality of markers 178 may be dynamically altered in real time during the performance of an MRI-guided procedure or across multiple MRI-guided procedures as described herein. For example, changing the relative positions of first and second medical devices 110, 150 in real time may produce a dynamic range of image artifacts under MRI.

[0040] 7 illustrates a third exemplary medical system 208 useful in performing a treatment under MRI (e.g., altering image artifacts under MRI). In this example, the second exemplary medical system 208 includes a first medical device 210 and a second medical device 250. In the illustrated embodiment, the first medical device 210 is a cannula 212 and the second medical device 250 is a stylet 252 that may be used coaxially with the first medical device 210. The cannula 212 is similar to the cannula 112 illustrated in FIG. 6 and described above, except as described in more detail below. The stylet 252 is similar to the stylet 152 illustrated in FIG. 6 and described above, except as described in more detail below.

[0041] In the illustrated embodiment, the cannula 212 has a longitudinal axis 213, a hub member 214, and an elongate member 216. The elongate member 216 of the cannula 212 is formed of a first material having a first magnetic susceptibility. In the illustrated embodiment, the elongate member 216 of the cannula 212 includes a first plurality of markers 246 disposed between a proximal end 230 and a distal end 232 of the elongate member 216. Each marker in the first plurality of markers 246 is a passive marker. The first plurality of markers 246 are spaced apart at varying distances along the elongate member 216. The first plurality of markers 246 includes a first subset of markers 280, a second subset of markers 282, and a third subset of markers 284. Each marker in the first subset of markers 280 is disposed between the proximal end 230 and the distal end 232 of the elongate member 216 of the first medical device 210 and around the entire circumference of the body 238 of the elongate member 216, and is formed of a second material different from the first material. The second material has a second magnetic susceptibility different from (e.g., greater than) the first magnetic susceptibility. Each marker in the first subset of markers 280 produces an image artifact under MRI having a first set of characteristics (e.g., size, shape, position, orientation, magnetic susceptibility, strength). Each marker in the second subset of markers 282 is disposed between the first subset of markers 280 and the third subset of markers 284, is disposed around only a portion of the circumference of the body 238, and is formed of a third material different from the first material and the second material. The third material has a third magnetic susceptibility different (e.g., greater than) the first magnetic susceptibility and different (e.g., greater than or less than) the second magnetic susceptibility. Each marker in the second subset of markers 282 produces an image artifact under MRI having a second set of properties (e.g., size, shape, position, orientation, magnetic susceptibility, strength) different from the first set of properties. Each marker in the third subset of markers 284 is disposed between the second subset of markers 282 and the distal end 232 of the elongate member 216, is disposed about only a portion of the circumference of the body 238, and is formed of a fourth material different from the first material, the second material, and the third material.The fourth material has a fourth magnetic susceptibility different (e.g., greater than) the first magnetic susceptibility, different (e.g., greater or less than) the second magnetic susceptibility, and different (e.g., greater or less than) the third magnetic susceptibility. Each marker in the third subset of markers 284 produces an image artifact under MRI having a third set of properties (e.g., size, shape, position, orientation, magnetic susceptibility, strength) different from the first set of properties and the second set of properties. The first subset of markers 280 includes three markers, the second subset of markers 282 includes one marker, and the third subset of markers 284 includes one marker. However, alternative embodiments may include any suitable number and type of markers in the multiple subsets of markers, and each subset of markers may be formed of any suitable material having a magnetic susceptibility as described herein.

[0042] In the illustrated embodiment, each marker in the first subset of markers 280 is a band of material attached to the elongate member 216, each marker in the second subset of markers 282 is a deposition of material attached to the elongate member 216 and is formed as a dot, and each marker in the third subset of markers 284 is a deposition of material attached to the elongate member 216 and is formed as a rectangle. Although the markers in the first plurality of markers 246 have been shown as being located at particular locations and having particular structural configurations on the elongate member 216, the markers included on the medical device may be located at any suitable location and have any suitable structural configuration.

[0043] In the illustrated embodiment, the stylet 252 has a hub member 254 and an elongate member 256. The elongate member 256 of the stylet 252 is formed of a fifth material having a fifth magnetic susceptibility. In the illustrated embodiment, the first material forming the elongate member 216 of the cannula 212 is different from the fifth material forming the elongate member 256 of the stylet 252.

[0044] In the illustrated embodiment, the elongate member 256 of the stylet 252 includes a second plurality of markers 278 disposed between the proximal end 266 and the distal end 268 of the elongate member 256. Each marker in the second plurality of markers 278 is a passive marker. The second plurality of markers 278 are spaced apart at varying distances along the elongate member 256. The second plurality of markers 278 includes a first subset of markers 286, a second subset of markers 288, and a third subset of markers 290. Each marker in the first subset of markers 286 is disposed between the proximal end 266 and the distal end 268 of the elongate member 256 of the second medical device 250 and around the entire circumference of the body 272 of the elongate member 256, and is formed of a sixth material different from the fifth material. The sixth material has a sixth magnetic susceptibility different from (e.g., greater than) the fifth magnetic susceptibility. Each marker in the first subset of markers 286 produces an image artifact under MRI having a first set of properties (e.g., size, shape, location, orientation, magnetic susceptibility, strength). Each marker in the second subset of markers 288 is disposed between the first subset of markers 286 and the third subset of markers 290, is disposed about only a portion of the circumference of the body 272, and is formed of a seventh material different from the fifth and sixth materials. The seventh material has a seventh magnetic susceptibility different from (e.g., greater than) the fifth magnetic susceptibility and different from (e.g., greater or less than) the sixth magnetic susceptibility. Each marker in the second subset of markers 288 produces an image artifact under MRI having a second set of properties (e.g., size, shape, location, orientation, magnetic susceptibility, strength) different from the first set of properties. Each marker in the third subset of markers 290 is disposed between the second subset of markers 288 and the distal end 268 of the elongate member 256 of the second medical device 250, is disposed about only a portion of the circumference of the body 272, and is formed of an eighth material that is different from the fifth, sixth, and seventh materials. The eighth material has an eighth magnetic susceptibility that is different (e.g., greater than) the fifth magnetic susceptibility and different (e.g., greater or less than) the sixth magnetic susceptibility and different (e.g., greater or less than) the seventh magnetic susceptibility.Each marker in the third subset of markers 290 produces an image artifact under MRI having a third set of properties (e.g., size, shape, position, orientation, magnetic susceptibility, intensity) that differs from the first set of properties and the second set of properties. The first subset of markers 286 includes three markers, the second subset of markers 288 includes one marker, and the third subset of markers 290 includes one marker. However, alternative embodiments may include any suitable number and type of markers in multiple subsets of markers, and each subset of markers may be formed of any suitable material having magnetic susceptibility as described herein.

[0045] In the illustrated embodiment, each marker in the first subset of markers 286 is a band of material attached to the elongate member 256, each marker in the second subset of markers 288 is a deposit of material attached to the elongate member 256 and is formed as a dot, and each marker in the third subset of markers 290 is a deposit of material attached to the elongate member 256 and is formed as a rectangle. Although the markers in the second plurality of markers 278 have been shown as being located at particular locations and having particular structural configurations on the elongate member 256, the markers included on the medical device may be located at any suitable location and have any suitable structural configuration.

[0046] Each marker in the second plurality of markers 278 is positioned on the elongate member 256 such that when the second medical device 250 is placed within the first medical device 210, the first plurality of markers 246 overlap (e.g., axially) the second plurality of markers 279 and the plurality of markers 246, 278 are aligned along the longitudinal axis 213 of the elongate member 216 of the cannula 212. For example, each marker in the second plurality of markers 278 is positioned on the elongate member 256 such that when the second medical device 250 is placed within the first medical device 210, the markers in the first plurality of markers 246 may overlap the second plurality of markers 278 and the markers in the first plurality of markers 246 and the markers in the second plurality of markers 278 are co-located along the longitudinal axis 213 of the elongate member 216 of the cannula 212.

[0047] The first material forming the elongate member 216 of the first medical device 210, the second material forming the elongate member 256 of the second medical device 250, and the material forming the markers included in the medical devices may comprise any suitable material. For example, the first material, the second material, the third material, the fourth material, the fifth material, the sixth material, the seventh material, and the eighth material may comprise any suitable MRI compatible material having a magnetic susceptibility as described herein. In the illustrated embodiment, the first material comprises titanium, the second material comprises a polymer, and each marker in the first plurality of markers 246 is formed of a material having a magnetic susceptibility that alters the image artifact of each marker in the second plurality of markers 278 under MRI when the marker in the first plurality of markers 246 overlaps (e.g., axially) a marker in the second plurality of markers 278 in use. Alternatively, each marker in the second plurality of markers may be formed from a material having a magnetic susceptibility that modifies image artifacts produced under MRI by each marker in the first plurality of markers when a marker of the first plurality of markers overlaps (e.g., axially) a marker of the second plurality of markers in use.

[0048] Each marker in the first subset of markers 280 is formed of a material different from the material forming each marker in the first subset of markers 286 such that the second material has a second magnetic susceptibility different from (e.g., greater than or less than) the sixth magnetic susceptibility (e.g., the magnetic susceptibility has a different sign). Each marker in the second subset of markers 282 is formed of a material different from the material forming each marker in the second subset of markers 288 such that the third material has a third magnetic susceptibility different from (e.g., greater than or less than) the seventh magnetic susceptibility (e.g., the magnetic susceptibility has a different sign). Each marker in the third subset of markers 284 is formed of a material different from the material forming each marker in the third subset of markers 290 such that the fourth material has a fourth magnetic susceptibility different from (e.g., greater than or less than) the eighth magnetic susceptibility (e.g., the magnetic susceptibility has a different sign).

[0049] In the illustrated embodiment, when first medical device 210 and second medical device 250 are used such that first plurality of markers 246 overlaps (e.g., axially) second plurality of markers 278, image artifacts caused by markers in first subset of markers 286 under MRI are amplified by markers in first subset of markers 280, or vice versa, image artifacts caused by markers in second subset of markers 288 under MRI are amplified by markers in second subset of markers 282, or vice versa, and image artifacts caused by markers in third subset of markers 290 under MRI are amplified by markers in third subset of markers 284, or vice versa. When a marker in first subset of markers 280 overlaps with a marker in first subset of markers 286, an altered image artifact occurs under MRI having a fourth set of properties (e.g., size, shape, location, orientation, magnetic susceptibility, intensity) that differ from the properties of the markers in first subset of markers 280 and first subset of markers 286. When a marker in second subset of markers 282 overlaps with a marker in second subset of markers 288, an altered image artifact occurs under MRI having a fifth set of properties (e.g., size, shape, location, orientation, magnetic susceptibility, intensity) that differ from the properties of the markers in second subset of markers 282 and second subset of markers 288. When markers in third subset of markers 284 and markers included in third subset of markers 290 overlap, altered image artifacts occur under MRI having a sixth set of properties (e.g., size, shape, position, orientation, magnetic susceptibility, intensity) that differ from the properties of the markers included in third subset of markers 284 and third subset of markers 290. Alternative embodiments may include subsets of markers on the first medical device formed of the same material as a corresponding subset of markers on the second medical device having the same magnetic susceptibility or same susceptibility such that image artifacts caused by markers in each subset are attenuated, eliminated, or amplified under MRI (e.g., magnetic susceptibility has the same sign).

[0050] Further, depending on the positions of the first medical device 210 and the second medical device 250 relative to each other, the markers of the third subset of markers 284 may modify image artifacts caused by the markers in the second subset of markers 288 under MRI or image artifacts caused by the markers in the first subset of markers 286 under MRI, or vice versa. Additionally, depending on the positions of the first medical device 210 and the second medical device 250 relative to each other, the markers of the second subset of markers 282 may modify image artifacts caused by the markers in the first subset of markers 286 under MRI, or vice versa.

[0051] Use of medical system 208 and first and second medical devices 210 and 250 may be advantageous at least because image artifacts caused under MRI by markers included in one of first and second plurality of markers 246 and 278 may be dynamically altered in real time during the performance of an MRI-guided procedure or across multiple MRI-guided procedures as described herein. For example, changing the relative positions of first and second medical devices 210 and 250 in real time may produce a dynamic range of image artifacts under MRI.

[0052] Although the markers shown on the medical devices described herein have been shown as bands of material, material deposited on the medical device forming a dot, and / or material deposited on the medical device forming a rectangle, the markers can include any suitable structure attached to the medical device (e.g., stylet, cannula) or any suitable treatment applied to the medical device. For example, the markers can include bands of material, magnetic ink, sputtered magnetite, dimpling, swaging, or peening of a material (e.g., annealed 304 stainless steel) forming a portion of the medical device, a single layer or multiple layers of one or more materials (e.g., metals, metal alloys) deposited along the exterior and / or interior surface of the medical device (e.g., an elongated member of the medical device), and / or any other material deemed suitable for forming a distinct marker (e.g., image artifact) that is visible under MRI and has the magnetic susceptibility described herein. Any suitable marker having the magnetic susceptibility described herein can be included on the medical device. Examples of markers that may be suitable for inclusion in medical devices are described in U.S. patent application Ser. No. 16 / 454,905, filed June 27, 2019, which is incorporated by reference in its entirety into this specification for the purposes of describing markers that may be suitable for inclusion in medical devices.

[0053] Each marker included in the medical device may have any suitable structural configuration and characteristics under MRI. For example, the marker may include a structure defining any suitable shape, such as a curve along a portion of the length of the elongate member, a geometric shape (e.g., circle, polygon) on a portion of the length of the elongate member, a spiral along a portion of the length of the elongate member, any combination of shapes described herein, or any other shape deemed suitable for a particular embodiment. The configurations described herein provide a mechanism for creating markers that have resultant image artifacts caused by the marker that are distinguishable under MRI from the surrounding fluid and / or tissue imaged under MRI.

[0054] Although the medical devices described herein include a cannula and a stylet, the markers described herein may be included in any suitable medical device that may be used in combination with one another (e.g., coaxially), and the selection of a suitable medical device to include a marker may be based on various considerations, including the intended use of the medical device in which the marker is placed. Examples of medical devices that may be suitable for including a marker include a cannula, a needle, a stylet, a sheath, a catheter, a balloon catheter, a dilator, a guidewire, an introducer, an implantable device, two medical devices that may be used in combination with one another (e.g., coaxially) (e.g., a needle and a guidewire, a guidewire and an introducer, a guidewire and a catheter, a guidewire and a sheath, a sheath and a catheter, an implantable medical device and associated delivery system, any medical device that may be passed over or through a guidewire, etc.), and any other medical device that may be suitable for a particular embodiment. Additionally, the features described herein may be utilized in three or more medical devices that may be used independently or in combination with one another.

[0055] The first medical device may include any suitable type of medical device. For example, the first medical device may include any suitable type of cannula having any suitable length and gauge. For example, the first medical device may include an Inconel Chiba needle, an Inconel micropuncture needle, or any other needle deemed suitable for a particular embodiment, and may have a length equal to, greater than, or less than 7 centimeters, 15 centimeters, or any other length deemed suitable for a particular embodiment, and / or may have a gauge equal to, greater than, or less than 20, 21, 22, or any other gauge deemed suitable for a particular embodiment. The second medical device may include any suitable type of medical device. For example, the second medical device may include any suitable type of stylet having any suitable length and gauge.

[0056] In addition, the medical devices described herein may be used with any suitable number of outer sheaths to accomplish a treatment. Selection of the appropriate number of outer sheaths to utilize, such as in completing the sequential expansion, may be based on, for example, the body passage in which the sequential expansion is to be completed. Examples of numbers of outer sheaths that may be suitable for utilization in completing the sequential expansion include one, two, multiple, three, four, five or more, and any other number that may be suitable for a particular embodiment.

[0057] Although a marker on a first medical device has been described as overlapping a marker on a second medical device so as to produce altered image artifacts in MR images, such overlap can include partial overlap between two markers (e.g., two coaxial markers) or complete overlap between two markers (e.g., two coaxial markers), depending on the structural configurations (e.g., size, shape, position, magnetic susceptibility, strength) of the markers that are intended to overlap one another.

[0058] Any type of modification of an image artifact can be accomplished by overlapping two markers, depending on the size, shape, position, magnetic susceptibility, and / or material the markers are made from. Examples of the types of modifications that can be accomplished using overlapping markers include modifying (e.g., removing, amplifying, attenuating) the size, shape, intensity, and / or appearance of an image artifact, as well as any other modification deemed suitable for a particular embodiment.

[0059] Although particular materials have been described as forming the first medical device (e.g., the elongate member), the second medical device (e.g., the elongate member), and the markers, the medical devices or portions thereof (e.g., the elongate member), and the markers can be formed of any suitable material having the magnetic susceptibility described herein to achieve the features described herein. For example, the first medical device, the second medical device, or portions thereof (e.g., the elongate member), and one or more markers included in the medical devices can be formed of any suitable MRI compatible material having the magnetic susceptibility described herein, and the selection of a suitable material can be based on various considerations including the intended use of the first medical device, the second medical device, and / or the markers. In addition, or in alternative embodiments, the first medical device, the second medical device, or portions thereof (e.g., elongate members), one or more markers included in the medical devices, and / or any other materials described herein may comprise any suitable MRI-compatible material that has a susceptibility or relative susceptibility, as well as a magnetic susceptibility or relative magnetic susceptibility, to the portions of the systems or devices from which the material forms, as described herein.Examples of materials that may be suitable for forming the first medical device, the second medical device, and / or one or more markers, or portions thereof, include biocompatible materials, materials that can be made into biocompatible materials, MRI compatible materials, non-ferromagnetic materials such as metals, electrically insulating materials, non-conductive materials, materials that are not susceptible to magnetism, non-diamagnetic materials, passive materials, diamagnetic materials (e.g., pyrolytic carbon), paramagnetic materials, or ferromagnetic materials, magnetically susceptible materials, ferromagnetic passive materials, including ferritic stainless steels, ferritic stainless steel 430L powder, nickel-titanium based alloys such as Nitinol, shape memory alloys, austenitic nickel-chromium based alloys such as Inconel, brands of Special Metals Corporation's family of austenitic nickel-chromium based superalloys, including austenitic stainless steels, stainless steel 304V Examples of suitable materials include SS, stainless steel containing iron, stainless steel including Inconel, iron, cobalt, cobalt chrome, cobalt chrome alloys, titanium, materials having a hardness of about 192 KSI (e.g., stainless steel), nickel, nickel plating, bright nickel plating, alloys containing less than 1% iron by weight, metals including murinite such as MuMetal, a brand of nickel-iron ferromagnetic alloy from Magnetic Shield Corporation that has very high magnetic permeability, gadolinium, pyrolytic carbon, silver, graphite, polycrystalline graphite, plastics, polymers, PEEK, carbon filled PEEK, polyethylene such as high density polyethylene (HDPE), polypropylene, polycarbonate, silicone, Delrin, ceramics, transparent materials, opaque materials, materials described herein, combinations of materials described herein, any other material deemed suitable for a particular embodiment and having the magnetic susceptibility described herein.The overlapping markers, or markers that can be overlapped during the performance of the procedure, can be formed of any suitable material, such as those described herein, paramagnetic materials (e.g., paramagnetic materials used to amplify image artifacts, materials including iron, nickel, cobalt (e.g., 300 series stainless steel), nickel-cobalt, cobalt chrome), ferromagnetic materials (e.g., ferromagnetic materials used to amplify image artifacts, materials including iron, nickel, cobalt (e.g., 300 series stainless steel), nickel-cobalt, cobalt chrome), diamagnetic materials (e.g., diamagnetic materials used to attenuate or eliminate image artifacts, pyrolytic carbon, silver, carbon (e.g., graphite)), and any other material deemed suitable for a particular embodiment.

[0060] The selection of one or more markers to include in a medical device may also be based on one or more magnetic field strengths in which the medical device is intended to be used. For example, a medical device including a marker may be utilized to complete one or more MRI-guided interventional procedures utilizing one or more magnetic field strengths (0.55 Tesla (T), 1.5T, or 3.0T). The resulting cumulative susceptibility-based artifact resulting from the overlap of two or more markers may be selected to respond differently in a single imaging sequence, or multiple imaging sequences (gradient echo vs. spin echo), or different magnetic field strengths. As described herein, a medical device is not limited to being used to alter the size, shape, and intensity of a single image artifact, but instead, a set of susceptibility markers across multiple devices may be combined (statically or dynamically) to alter the geometry of a larger (or smaller) cumulative artifact, resulting in a distinct image artifact that is easily identifiable under MRI.

[0061] As described herein, visualization of devices during the performance of procedures is a fundamental challenge in interventional MRI. Conventional interventional devices and materials are either highly susceptible, resulting in artifacts that wash out key features of the imaged tissue / magnetic field, or are minimally susceptible, leaving the device invisible for identification or tracking in the image. Thus, there is a need to directly leverage diagnostic imaging modalities, particularly MR, to guide treatment. Identification and precise targeting of lesions or abnormal anatomical structures is a clinically significant challenge. The medical devices described herein are considered advantageous, at least because they substantially improve the clinician's ability to accurately visualize, identify, track, and navigate medical devices to various locations within the body, thus improving overall patient care (e.g., diagnosis, treatment delivery). The medical devices described herein provide markers that can be used to produce identifiable and manipulable image artifacts (e.g., patterns) on interventional MR images, allowing a high degree of control over the location, size, and intensity of the markers and associated medical devices under MRI.

[0062] Figure 8 illustrates an exemplary kit 300 useful in performing a procedure under MRI. The kit 300 includes a first medical system 302 according to an embodiment, such as the first medical system 8 shown in Figures 1, 2, 3, 4, and 5, a second medical system 304 according to an embodiment, such as the second medical system 108 shown in Figure 6, a third medical system 306 according to an embodiment, such as the third medical system 208 shown in Figure 7, and instructions 308 for use.

[0063] Although the kit 300 has been shown as including three medical systems 302, 304, and 306, any suitable number and type of medical systems and / or devices may be included in the kit. Selection of an appropriate number of medical systems and / or devices to include in a kit according to a particular embodiment may be based on a variety of considerations, such as the treatment intended to be performed. Examples of numbers of medical systems and / or devices that may be suitable for inclusion in a kit include at least one, one, two, multiple, three, four, five, six, seven, eight, nine, ten, eleven or more, and any other number that may be suitable for a particular embodiment.

[0064] Additionally, although medical system 8, medical system 108, and medical system 208 have been shown as being included in kit 300, any suitable medical system and / or medical device may be included in the kit. Selection of a suitable medical system and / or medical device for inclusion in a kit according to a particular embodiment may be based on a variety of considerations, such as the treatment intended to be performed. Examples of medical systems and / or medical devices that may be suitable for inclusion in a kit include those described herein, variations of those described herein, one or more inner sheaths, one or more outer sheaths, one or more access needles, one or more implantable medical devices, one or more delivery systems, and / or any other medical device according to an embodiment that may be suitable for a particular embodiment.

[0065] For example, in an embodiment in which the kit includes multiple medical devices (e.g., a needle and multiple stylets), the first medical device (e.g., stylet) may include a marker formed of a material that produces an image artifact under a first MR magnetic field strength (e.g., 0.55T), the second medical device (e.g., stylet) may include a marker formed of a material that produces an image artifact under a second MR magnetic field strength (e.g., 1.5T), and the third medical device (e.g., stylet) may include a marker formed of a material that produces an image artifact under a third MR magnetic field strength (e.g., 3T). The first MR magnetic field strength may be different or the same as the second MR magnetic field strength and / or the third MR magnetic field strength. The second MR magnetic field strength may be different or the same as the first MR magnetic field strength and / or the third MR magnetic field strength. The third MR magnetic field strength may be different or the same as the first MR magnetic field strength and / or the second MR magnetic field strength. Each of the first, second, and third medical devices (eg, a stylet) can be used in conjunction with a fourth medical device (eg, a needle) to perform a procedure.

[0066] In one example, a kit useful in performing a treatment under magnetic resonance comprises a first medical device of an embodiment, a second medical device of an embodiment, and a third medical device of an embodiment. The first medical device comprises a first marker that produces a first image artifact under a first MR magnetic field strength. The second medical device comprises a second marker that produces a second image artifact under a second MR magnetic field strength. The third medical device comprises a third marker that produces a third image artifact under a third MR magnetic field strength. The first MR magnetic field strength is different from the second MR magnetic field strength and the third MR magnetic field strength. The second MR magnetic field strength is different from the third MR magnetic field strength. The first image artifact has a first set of characteristics (e.g., size, shape, pattern, and / or strength) under the first MR magnetic field strength, a second set of characteristics under the second MR magnetic field strength, and a third set of characteristics under the third MR magnetic field strength. The first set of characteristics of the first image artifact is different from the second set of characteristics of the first image artifact and the third set of characteristics of the first image artifact. The second set of characteristics of the first image artifact is different from the third set of characteristics of the first image artifact. The second image artifact has a first set of characteristics under a first MR magnetic field strength, a second set of characteristics under a second MR magnetic field strength, and a third set of characteristics under a third MR magnetic field strength. The first set of characteristics of the second image artifact is different from the second set of characteristics of the second image artifact and the third set of characteristics of the second image artifact. The second set of characteristics of the second image artifact is different from the third set of characteristics of the second image artifact. The third image artifact has a first set of characteristics under a first MR magnetic field strength, a second set of characteristics under a second MR magnetic field strength, and a third set of characteristics under a third MR magnetic field strength. The first set of characteristics of the third image artifact is different from the second set of characteristics of the third image artifact and the third set of characteristics of the third image artifact. The second set of characteristics of the third image artifact is different from the third set of characteristics of the third image artifact.

[0067] 9 and 10, the medical system 310 may include a first medical device 312, a second medical device 314, a third medical device 316, and a fourth medical device 318 that may be used concentrically. According to one embodiment, the first medical device 312 includes a needle (e.g., a needle formed of titanium). According to one embodiment, the second medical device 314, the third medical device 316, and the fourth medical device 318 each include a stylet. The first medical device 312 may be packaged with multiple stylets 314, 316, 318, each of which may be used in combination with a needle, either independently or collectively, depending on the MRI static magnetic field strength intended to be used or the particular interventional procedure to be completed. For example, each stylet of the plurality of stylets 314, 316, 318 comprises a marker 320 having a magnetic susceptibility that amplifies, eliminates, or attenuates the magnetic susceptibility caused by the marker 322 disposed on the needle 312 under MRI, or vice versa, thereby modifying the image artifact of the marker 322 disposed on the needle 312. This may be accomplished in discrete increments (e.g., 0.25x, 0.5x, 2.0x, 4.0x, etc.) depending on the number of overlapping markers. These stylets may then be used independently or collectively to adjust the size of the image artifact in real time throughout or across multiple procedures. In embodiments where stylets are used collectively, the stylets may be made using a series of concentric tubes as shown, and any suitable number of concentric tubes may be utilized.

[0068] The kits described herein advantageously provide clinicians with a single product (e.g., a kit) that can be used in multiple settings. For example, a titanium needle with low magnetic susceptibility allows precision of positioning near the tip where treatment is performed (e.g., where a biopsy is performed), while markers on one or more of the removable stylets allow real-time trackability at any magnetic field strength or across multiple interventional procedures. Although the present embodiment describes the use of a needle and multiple stylets, such an embodiment may include any suitable combination of medical devices such as those described herein (e.g., sheath, removable dilator). For example, a sheath formed of a material that produces no or slightly visible image artifacts under MRI may be packaged with multiple removable dilators, each of which includes one or more markers that produce highly visible image artifacts under MRI to facilitate use under various MRI static magnetic field strengths.

[0069] Various methods of performing MRI-guided interventional procedures are described herein. Although the methods described herein are illustrated and described as a series of acts, it is to be understood and appreciated that the methods are not limited by the order of acts, as some acts of the methods may be omitted, performed in the order shown and / or described, performed in a different order, and / or performed prior to, following, or concurrently with other acts described herein.

[0070] FIG. 11 shows a schematic diagram of an exemplary method 400 for performing therapy (eg, modifying image artifacts) under MRI.

[0071] A first step 402 includes placing a patient in an MR scanner. Another step 404 includes scanning a first portion of the patient using the MR scanner. The MR scanner has a first set of MR image parameters and / or sequence parameters. Another step 406 includes acquiring an MR image of the first portion of the patient. Another step 408 includes identifying tissue having predefined characteristics using the MR images. Another step 410 includes selecting a procedure for treating the tissue based on the predefined characteristics. Another step 412 includes selecting a medical system to carry out the execution of the procedure. The medical system comprises a first medical device and a second medical device. The first medical device has a first marker and the second medical device has a second marker. While the patient is positioned in the MR scanner used to scan the first portion of the patient, another step 414 includes inserting the first and second medical devices into the body passageway and up to the tissue (e.g., concentrically) while scanning the second portion of the patient including the first and second medical devices and the first image artifact using the MR scanner. The first image artifact has a first set of characteristics. Another step 416 includes acquiring an MR image of the second portion of the patient including the first and second medical devices and the first image artifact. Another step 418 includes identifying the first image artifact in the MR image. Another step 420 includes verifying the position of the first and second medical devices in the body passageway. Another step 422 includes manipulating the position of the first medical device relative to the second medical device, or vice versa, to modify the first image artifact resulting in a modified image artifact. Another step 424 includes scanning an image of a third portion of the patient including the first and second medical devices and the altered image artifact using the MR scanner. Another step 426 includes acquiring an MR image of the third portion of the patient including the first and second medical devices and the altered image artifact.Another step 428 includes modifying (e.g., optimizing) the first set of MR image parameters and / or sequences to a second set of MR image parameters and / or sequences based on the modified image artifacts. Another step 430 includes delivering a treatment.

[0072] Step 402 may be performed by placing the patient in any suitable MR scanner having any suitable magnetic field strength (such as a conventional MR scanner, an MR scanner capable of performing gradient refocusing echo imaging, an MR scanner capable of performing spin echo imaging, an MR scanner capable of performing true high speed imaging with steady state precession, an MR scanner capable of performing high speed low flip angle shot spoiled gradient echo imaging, an MR scanner utilizing a magnetic field of 0.55T, a magnetic field of 1.5T, a magnetic field of 3T, a magnetic field between about 0.055T and 1.5T, a magnetic field less than 1T, and any other MR scanner deemed suitable for the particular embodiment).

[0073] Step 404 may be accomplished by scanning any suitable portion of the patient, and the selection of the suitable portion of the patient to scan may be based on various considerations, including the treatment intended to be performed. Examples of portions of the patient that may be suitable for scanning include the extremities (e.g., arms, legs), chest, breasts, spine, neck, head, abdomen, pelvis, prostate, perifrostatic structures, tissue surrounding the portions of the patient described herein, and / or any other portion of the patient that may be suitable for a particular embodiment. The MR scanner may have any suitable number and type of MR imaging parameters, such as gradient refocusing echo imaging, spin echo imaging, true high speed imaging with steady state precession, high speed low flip angle shot spoiled gradient echo imaging, magnetic field strengths such as 0.55T, 1.5T, 3T, about 0.055T to 1.5T, and less than 1T, slice thickness, flip angle, field of view, resolution, gradient magnetic field, and any other imaging parameters that may be suitable for a particular embodiment.

[0074] Step 406 may be performed by acquiring MR images from the MR scanner used in step 404 .

[0075] Step 408 may be accomplished by reviewing the MR images acquired in step 406 and utilizing conventional techniques and / or methods to determine whether the tissue has predefined characteristics (e.g., the tissue has characteristics indicative of cancer, is a lesion, is an abnormal mass), etc. Additionally, margins of any tissue (e.g., an abnormal mass) may be identified and used in further steps to remove and / or treat the tissue, as described herein.

[0076] Step 410 may be performed by reviewing the predefined characteristics identified in step 408 and selecting a procedure for treating the tissue based on the predefined characteristics.

[0077] Step 412 may be performed based on the procedure selected in step 410, the available MR scanners, and / or the MR magnetic field strength desired to complete the procedure. Any suitable medical system (e.g., first medical device and second medical device), such as those described herein, variations of those described herein, and any other medical system and / or medical device deemed suitable for a particular embodiment, may be selected to perform the performance of the procedure. Alternatively, the medical system and / or medical device may be selected from a kit, such as kit 300, or a variation of a kit described herein. Each of the medical devices described herein comprises one or more markers that produce one or more image artifacts under MRI having a set of characteristics.

[0078] Step 414 may be performed using the medical system (e.g., the first medical device and the second medical device) selected in step 412. Alternatively, step 414 may be performed using any suitable medical device, such as those described herein or incorporated by reference herein. Examples of medical devices that may be suitable for use to complete a method of treatment, and other steps that may be suitable for inclusion in a method of treatment, are described in U.S. Patent Application No. 17 / 573,087, filed January 11, 2022, which is incorporated by reference in its entirety for purposes of describing medical devices that may be suitable for completing a method of treatment, and for purposes of describing steps that may be suitable for inclusion in a method of treatment.

[0079] Step 414 may be performed by applying a distally directed force to the first medical device such that the distal end of the first medical device is inserted into the body passageway and into, within, or adjacent to tissue identified as having the predefined characteristic. Additionally, step 414 may be performed by applying a distally directed force to the second medical device such that the distal end of the second medical device is inserted into a lumen defined by the first medical device and distal to the first medical device. Insertion of the second medical device may be performed simultaneously with insertion of the first medical device, prior to insertion of the first medical device, or after insertion of the first medical device. Alternatively, the second medical device may be inserted into the lumen defined by the first medical device until the distal end of the second medical device is disposed within the lumen defined by the first medical device and between the proximal and distal ends of the first medical device.

[0080] The body passageway may include any suitable portion of the body, including existing body passageways, body lumens, and / or body passageways created through tissue layers and / or fascia using the devices described herein. Step 414 may be accomplished by scanning any suitable portion of the patient, and the selection of the suitable portion of the patient to scan may be based on various considerations, including the location of tissue having predefined characteristics. Examples of portions of the patient that may be suitable for scanning include portions that include tissue having predefined characteristics, portions that include the first and / or second medical devices, portions that include image artifacts and / or altered image artifacts, portions that include tissue having predefined characteristics and the first and / or second medical devices, and / or any other portion of the patient that may be suitable for a particular embodiment. For example, the second portion of the patient may be the same or different from the first portion of the patient.

[0081] Although step 414 has been described as being completed using both the first and second medical devices, step 414 may be accomplished in two alternative ways. In the first alternative way, the first step includes inserting the first medical device into the body passageway and up to the tissue while scanning the second portion of the patient including the first medical device using the MR scanner. The second step includes inserting the second medical device into the body passageway and up to the tissue while scanning the second portion of the patient including the second medical device using the MR scanner. In the second alternative way, the first step includes inserting the second medical device into the body passageway and up to the tissue while scanning the second portion of the patient including the second medical device using the MR scanner. The second step includes inserting the first medical device into the body passageway and up to the tissue while scanning the second portion of the patient including the first medical device using the MR scanner.

[0082] Image artifacts produced by MRI may include any image artifact produced by a marker included on any medical device or a combination of markers included on a combination of medical devices. For example, a first image artifact may be produced by a marker placed on a first medical device, a marker placed on a second medical device, a combination of markers included on a first medical device and a second medical device, overlapping markers (e.g., altered image artifacts), and / or any other markers deemed suitable for a particular embodiment.

[0083] Step 416 and its alternatives may be accomplished by acquiring MR images from the MR scanner used in steps 402 and 414. Figure 12 shows an MR image 500 showing a first medical device 502 and a second medical device 503 positioned within a body passageway 504. The first medical device 502 comprises a first plurality of markers 506. Each marker of the first plurality of markers 506 has a first magnetic susceptibility that results in an image artifact 508. The second medical device 503 comprises a second plurality of markers 507. Each marker of the second plurality of markers 507 has a second magnetic susceptibility that is different from the first magnetic susceptibility and results in an image artifact 509. Each of the image artifacts 508, 509 has a set of characteristics.

[0084] Step 418 may be accomplished by reviewing the MR images acquired in step 416 and identifying characteristics of image artifacts in the images. This may be accomplished using software (e.g., software having artifact recognition, localization, tracking, image processing, and / or machine learning) included in the MR scanner used in step 402 and / or visually by a clinician. For example, the MR scanner used in step 402 and the remaining steps included in method 400 may comprise a database associating characteristics of image artifacts with each medical device, characteristics of image artifacts of combinations of medical devices with combinations of medical devices, and / or characteristics of image artifacts caused by overlaying markers with combinations of medical devices, the database being used to perform a treatment such that when an image artifact is identified by the MR scanner using the characteristics of the image artifact, the MR scanner may identify and / or track the medical device or combination of medical devices, modify a first set of MR image parameters and / or sequence parameters as described herein to a second set of MR image parameters and / or sequence parameters, and / or modify an image created by the MR scanner to create a modified MR image. The image artifact characteristics included in the database may include those described herein, such as the size, shape, location, orientation, pattern, and / or intensity of the image artifact. For example, each of medical devices 10, 50, 110, 150, 210, 250, 312, 314, 316, and 318 has a pattern of markers that distinguish it from the other medical devices. As a result, each of medical devices 10, 50, 110, 150, 210, 250, 312, 314, 316, and 318, or combinations of medical devices, have distinguishing image artifact characteristics (e.g., patterns or codes) that can be identified under MRI using the database included in the MR scanner.Image processing software or machine learning can optionally be used to determine the status of these markers or image artifacts in near real-time, aiding in the estimation of device placement with automated sequence selection and enabling path planning to target locations that avoids critical or sensitive anatomical structures during treatment.

[0085] Step 420 may be accomplished by reviewing the MR images acquired in step 416 and verifying that the first and second medical devices are positioned in the desired location in the body passageway (e.g., at, in, or adjacent to tissue identified as having a predefined characteristic). This may be accomplished by visualizing an image artifact caused by markers included in the first and / or second medical devices, as described herein. If the first and / or second medical devices are not positioned in the desired location, an optional step includes manipulating the position of the first and / or second medical devices. If the first and / or second medical devices are not positioned in the desired location, an optional step 432 includes repeating steps 414, 416, 418, and 420 to manipulate the position of the first and / or second medical devices (e.g., in real time). Although steps 414, 416, 418, and 420 are shown as separate steps, these steps may optionally be completed simultaneously in real time. Optional step 432 may be performed any suitable number of times to accurately position the first and / or second medical devices.

[0086] An optional step, which may be completed following steps 418 and / or 420 or at any other time upon completion of method 400, includes modifying the first set of MR image parameters and / or sequence parameters (e.g., SE / GRE, TR, TE, flip angle, field of view, resolution, slice thickness, gradient fields) to a second set of MR image parameters and / or sequence parameters based on the identified image artifacts. This optional step may be performed in step 402 and / or using software included in the MR scanner used by the clinician. This step may be performed such that the MR image parameters and / or sequence parameters are periodically modified or updated based on image artifacts caused by one or more markers located on the first medical device, the second medical device, and / or a combination of the first and second medical devices whenever an MR image is captured, an image artifact is detected, a modified image artifact is detected, an image artifact is modified, multiple image artifacts are detected, or a combination of image artifacts is detected. The modified MR image may include an overlay graphic of the identified medical device (e.g., a portion of a medical device, the entire medical device), or combination of medical devices, using characteristics of the image artifact or combination of image artifacts, may include amplification, attenuation, or omission of the identified medical device (e.g., a distal end), combination of medical devices, image artifact, or other object in the image, and / or any other image manipulation deemed suitable for a particular embodiment. For example, the modified MR image may include manipulation of plane, slice, slice thickness, and / or sequence parameters based on the identified image artifact. For example, once an image artifact or modified image artifact is identified by software or a clinician, image parameters (e.g., those related to plane selection, slice, slice thickness, plane, sequence parameters) may be automatically modified (e.g., by the MR scanner software) based on the identified image artifact or modified image artifact.

[0087] Step 422 may be accomplished by applying a force (e.g., a distally directed force, a proximally directed force, a torque) to the first and / or second medical device to modify (e.g., amplify, attenuate, remove) the first image artifact. This may be accomplished as described herein (e.g., by positioning the first and second medical devices such that a marker on the first medical device overlaps (e.g., axially) a marker on the second medical device, or by positioning the first and second medical devices such that a marker on the first medical device does not overlap a marker on the second medical device). This step advantageously provides a mechanism to dynamically adjust the markers and resulting image artifacts as the procedure is completed (e.g., in real time, under continuous MR imaging), so that the way the MR scanner operates may be changed (e.g., changing imaging parameters and / or changing sequence parameters) as described herein. For example, a clinician can modify one or more image artifacts (e.g., turn them on (amplify) or turn them off (attenuate)) by manipulating the relative positions of the first and second medical devices and markers included on the first and second medical devices.

[0088] As described herein, there is a need to directly leverage diagnostic imaging modalities, particularly MR, to guide treatment. Thus, identifying and precisely targeting specific characteristics of tissue (e.g., lesions, abnormal anatomical structures) is a significant clinical challenge. The medical systems, devices, kits, and methods described herein are intended to significantly improve upon conventional interventional MRI techniques by providing clinicians with the ability to dynamically change the visibility of image artifacts caused by markers included on medical devices through or across multiple procedures using passive markers. The medical systems, devices, kits, and methods described herein enable precise identification, tracking, and navigation of interventional devices to various locations within the body, and use the characteristics of image artifacts caused by a medical device or combination of medical devices to improve the overall care of the patient (e.g., diagnosis, delivery of targeted treatment, etc.).

[0089] For example, during at least a portion of an interventional procedure, the first and second medical devices may be positioned such that the markers on the first medical device overlap the markers on the second medical device to modify (e.g., remove, attenuate, amplify) image artifacts and image artifact-related properties of the markers on the first medical device and / or the markers on the second medical device. In both subtractive and additive configurations, a marker having a magnetic susceptibility along the second medical device may be adjusted to interact differently with the markers on the first medical device based on its position or orientation relative to the first medical device and / or the markers positioned on the first medical device. For example, the first and second medical devices may be designed with two artifact placement modes. That is, in one arrangement, the first and second medical devices are arranged such that one alternative set of image artifacts caused by the markers on the first medical device is counteracted (or amplified) by the image artifacts caused by the markers on the second medical device, and in the other arrangement, a different set of image artifacts of the first medical device is counteracted (or amplified) by the image artifacts caused by the markers on the second medical device. In this manner, the size, shape, and intensity of the image artifacts of the first medical device can be dynamically shifted or altered along the first medical device (e.g., the elongate member) at any time during the procedure. Application of these concepts is extended as device tracking, following the changes in the set of image artifacts as the devices move relative to each other, or how to dynamically adjust the set of image artifacts and their associated characteristics to better suit a particular portion of the procedure.

[0090] The medical systems, devices, kits, and methods described herein can be used to produce distinct image artifacts in MR images that can be identified using software (e.g., software with artifact recognition, localization, tracking, image processing, and / or machine learning). Furthermore, as described herein, the cumulative susceptibility-based artifacts resulting from the combination of multiple devices can be tuned to respond differently in single or multiple imaging sequences (gradient echo vs. spin echo), or different magnetic field strengths. In these procedures, image processing software or machine learning can optionally be used to determine the status of these markers in near real-time, aiding in the estimation of device placement with automated sequence selection and enabling path planning to target locations that avoids critical or sensitive anatomical structures during therapy delivery.

[0091] Step 424 may be accomplished as described herein and by scanning any suitable portion of the patient, and selection of the suitable portion of the patient to scan may be based on various considerations including the location of tissue having the predefined characteristic. Examples of portions of the patient that may be suitable for scanning include portions including tissue having the predefined characteristic, portions including the first and / or second medical devices, portions including image artifacts and / or altered image artifacts, portions including tissue having the predefined characteristic and the first and / or second medical devices, and any other portions of the patient that may be suitable for a particular embodiment. For example, the third portion of the patient may be the same or different from the first portion of the patient and / or the second portion of the patient.

[0092] Step 426 may be accomplished by acquiring an MR image from the MR scanner used in step 402. FIG. 13 shows an MR image 510 depicting a first medical device 512 and a second medical device 514 disposed within a body passageway 516. The first medical device 512 comprises a first plurality of markers 518 and the second medical device 514 comprises a second plurality of markers 520. The overlapping configuration of the first plurality of markers 518 and the second plurality of markers 520 alters (e.g., amplifies, attenuates, removes) image artifacts caused by the first plurality of markers 518. In the embodiment shown in FIG. 13, when the first plurality of markers 518 and the second plurality of markers 520 overlap, image artifacts caused by the first plurality of markers 518 and the second plurality of markers 520 are removed. 14 shows an MR image 528 depicting a first medical device 530 and a second medical device 532 disposed within a body passageway 534. The first medical device 530 comprises a first plurality of markers 536 and the second medical device 532 comprises a second plurality of markers 538. The overlapping configuration of the first and second plurality of markers 536 and 538 alters (e.g., amplifies) the image artifact 540 caused by the first plurality of markers 536. FIG. 15 shows an MR image 550 depicting a first medical device 552 and a second medical device 554 disposed within a body passageway 556. The first medical device 552 comprises a first plurality of markers 558 and the second medical device 554 comprises a second plurality of markers 560. The overlapping configuration of markers 562 of the first plurality of markers 558 and markers 564 of the second plurality of markers 560 modifies (e.g., amplifies, attenuates, or eliminates) image artifacts caused by markers 562 of the first plurality of markers 558.

[0093] Step 428 may be performed using software included in the MR scanner used in step 402 (e.g., software having artifact recognition, localization, tracking, image processing, and / or machine learning) and / or by a clinician. Depending on whether the image parameters and / or sequence parameters have been updated prior to step 428, step 428 may alternatively include modifying the second set of MR image parameters and / or sequence parameters to a third set of MR image parameters and / or sequence parameters based on the image artifact or the modified image artifact. Optionally, step 428 may be performed such that whenever an MR image is captured (e.g., step 404, step 414, step 424) and an image artifact is detected, an altered image artifact is detected, multiple image artifacts are detected, a combination of image artifacts is detected, and / or an image artifact is altered (e.g., step 414, step 424), the MR image parameters and / or sequence are periodically altered or updated based on the altered and / or altered image artifacts caused by one or more markers disposed on the first medical device, the second medical device, and / or a combination of the first and second medical devices. This step may be performed in step 602 and / or using software included in the MR scanner used by the clinician. The modified MR image may include an overlay graphic of an identified medical device (e.g., a portion of a medical device, an entire medical device), or combination of medical devices, using characteristics of an image artifact or a combination of image artifacts, may include amplification, attenuation, or omission of an identified medical device (e.g., a distal end), combination of medical devices, image artifacts, or other objects in the image, and / or any other image manipulation deemed suitable for a particular embodiment. For example, the modified MR image may include manipulation of planes, slices, slice thicknesses, and / or sequence parameters based on the identified image artifacts.For example, when an image artifact or an altered image artifact is identified by the software or a clinician, image parameters (e.g., those related to plane selection, slice, slice thickness, plane, sequence parameters) may be automatically altered (e.g., by the MR scanner software) based on the detected image artifact or altered image artifact.

[0094] Interventional MR procedures generally require frequent adjustments or changes to MR imaging sequence parameters throughout the various stages of a given procedure. For example, a vascular procedure may be optimally performed with one sequence type during device tracking (e.g., fast frame rate, low resolution, emphasis on specific tissue properties) and another sequence type once the interventional device has been inserted to the target site (e.g., higher resolution, emphasis on different tissue properties to detect lesions such as inflammation, ADC, etc.). Alternatively, one or more interventional devices may be employed across multiple MRI-based procedures, requiring specific imaging sequences for the particular device and procedure configuration. For example, an MRI-compatible needle may be used across multiple soft tissue biopsy procedures, each requiring different gross or fine tracking properties and emphasizing different anatomical structures or tissue types. Traditionally, many of these imaging protocols involve manual optimization by clinicians using MR scanners, which can lead to operator-to-operator variability and inefficiency.

[0095] Thus, the medical systems, devices, kits, and methods described herein provide mechanisms to at least increase efficiency when a procedure is completed. For example, software included in an MR scanner, such as that utilized to complete the methods described herein, may be utilized to provide automation of parameter adjustment throughout or across procedures (e.g., plane selection, slice selection) based on identified image artifacts caused by changes in image artifacts caused by one or more markers provided on a first medical device, one or more markers made on a second medical device, and / or overlapping markers, as described herein. Thus, the presence of one or more image artifacts and / or dynamic changes in image artifacts resulting from different device or component configurations may be used by the MR scanner or clinician to automate the selection of MR sequence parameters.

[0096] In some procedures, the transition from one procedural stage to another may coincide with a specific configuration of two or more devices and require a change in the imaging protocol. Dynamic changes in the artifacts of the markers on these devices may be adjusted to produce easily identifiable image artifacts (e.g., changes in signal, size, shape, intensity, or pattern) or changes in image artifacts in the resulting MR images. Imaging software included in MR scanners, such as those used to complete the methods described herein, can detect image artifacts or changes in image artifacts and automatically optimize MR imaging parameters and / or sequences to those best able to meet the clinician's needs for the new stage of the procedure.

[0097] The medical systems, devices, kits, and methods described herein can be used to automatically change other imaging parameters and / or sequences within a procedure or across multiple procedures using the same one or more devices. For example, changes in MR sequence parameters (SE / GRE, TR, TE, flip angle, field of view, resolution, slice thickness, gradient fields) can be triggered by characteristics of valid image artifacts caused by a medical device, or a particular combination of two or more medical devices that results in a cumulative change in at least one image artifact. These artifact-driven triggers can be used to signal device tracking transitions to guide how the MR sequence is adapted to track devices or components in the magnetic fields of multiple devices, and / or to adjust the MR sequence to emphasize specific tissue characteristics during specific parts of the procedure (e.g., T1 v. T2 weighted images).

[0098] For example, a set of sequential MR sequence parameters may be triggered sequentially based on identified image artifacts or altered image artifacts caused by current and / or previous configurations of one or more devices. This process may then be used to automate imaging protocols throughout the procedure. Alternatively, utilizing a single basal device and multiple different corresponding medical devices (e.g., various guiding catheters or balloon catheters) all having one or more uniquely interacting susceptibility markers, a particular imaging procedure associated with the use of at least one corresponding device with the basal device may be automatically detected based on the identification of unique image artifacts caused by an initial multi-device configuration (e.g., a combination of image artifacts caused by a first medical device and a second medical device). With this pairing detection, a set of pre-programmed MRI sequences may be automatically loaded and triggered by software included in the MR scanner based on image artifacts caused by the above-mentioned sequential device configurations. In other words, the image artifact (or series of artifacts) created by the interaction of susceptibility markers on two or more medical devices serves as a unique fingerprint to identify a particular medical device pairing or device configuration, and the MRI system is automatically reconfigured to the procedure, or the next step in the procedure.

[0099] Step 430 may be accomplished by performing a treatment using any appropriate medical system and / or medical device, such as a first medical device and / or a second medical device, and / or executing the procedure selected in step 410. For example, a treatment may be performed and based on the tissue identified in step 408. Examples of treatments that may be suitable for performing include a biopsy, a treatment using the medical systems and / or medical devices described herein, using a first medical device already in place in the body passageway and replacing the second medical device with a third medical device, and any other treatments that may be suitable for a particular embodiment.

[0100] Each of steps 404, 406, 408, 410, 412, 414, 416, 418, 420, 422, 424, 426, 428, and / or 430 may be performed without the patient leaving the MR scanner in which the patient was placed in step 402.

[0101] Method 400 is believed to be advantageous at least because each step of method 400 is performed during a single patient visit using the same MR scanner, resulting in increased efficiency and reduced number of patient visits and procedures performed. This results in a set of procedures that allow a physician to visualize, diagnose, and treat a patient during a single patient visit. Although some steps are described as being completed while scanning a portion of a patient using an MR scanner and other steps are not described as being performed while scanning a portion of a patient using an MR scanner, any step described herein may be completed while scanning a portion of a patient using an MR scanner and / or an ultrasound device or without scanning a portion of a patient using an MR scanner. In embodiments in which ultrasound images are acquired, the acquired MR images may be electronically fused with real-time ultrasound images (e.g., transrectal ultrasound images of the prostate). Although some steps are described as being completed while scanning a portion of a patient using an MR scanner, the steps may be split into two separate steps such that a subsequent step of scanning a portion of a patient using an MR scanner may be accomplished. Additionally, any steps completed while scanning a portion of a patient using an MR scanner may include acquiring a single still image, which may be repeated any desired number of times to acquire multiple MR images that may be grouped as a cine to show motion, and / or any steps completed while scanning a portion of a patient using an MR scanner may include acquiring live images, such as being completed under live real-time MRI visualization.

[0102] The medical systems, devices, kits, and methods described herein advantageously provide susceptibility-based maker artifacts that can be dynamically altered throughout a procedure or across multiple procedures using a system or set of differently configured devices, components, or features. In this manner, the medical systems, devices, kits, and methods described herein extend the traditional use of fixed susceptibility marker artifacts and increase the versatility of medical device use in MR-guided interventional procedures. In addition, by utilizing the position-based additive and subtractive properties of the distortion of the magnetic field by the susceptibility markers (e.g., superposition), the medical systems, devices, kits, and methods described herein can be utilized in a variety of medical devices that can be used in combination with each other. Finally, the medical systems, devices, kits, and methods described herein can replicate, or at least mimic, aspects of the dynamically adjustable image artifacts produced by semi-active resonant circuits or active antenna coils, but without requiring built-in circuitry or external power sources.

[0103] An interventional system with dynamically adjustable passive markers that can adjust the size, shape, or intensity of image artifacts in real time throughout a procedure or across multiple procedures would increase the efficiency associated with patient care and improve upon conventional medical systems that are considered suitable for use in MRI-guided procedures. For example, the medical systems, devices, kits, and methods described herein simplify the clinician's experience during MRI-guided procedures. This includes automatically recognizing marker image artifacts or changes, interpreting new marker image artifacts as representing a new stage in the procedure or as a new procedure, and based on the identified image artifacts, modifying or optimizing MR sequence parameters to best meet the clinician's needs at a given phase or stage of the procedure. This eliminates the need for manual sequence adjustments and standardizes procedure and imaging parameters, improving the safety and efficiency of interventional MR procedures.

[0104] Although several methods have been described herein, it will be appreciated that the methods may be non-invasive methods that do not require invasive intervention by a medical professional. For example, the methods may be performed within a body cavity or passageway, such as, for example, the ear canal or nasal cavity, to place a device within such passageway. Similarly, the methods may be performed on a cadaver or artificial body part, for example for training purposes. Furthermore, those skilled in the art will recognize that the methods described herein may not be used on a human or animal body at all, but may be used to view other types of devices using MRI imaging techniques, for example in an industrial setting.

[0105] Those skilled in the art will recognize that, in light of the overall teachings of the present disclosure, various modifications and alternatives to the described and illustrated examples can be developed, and that various elements and features of one example described and illustrated herein can be combined with various elements and features of another example without departing from the scope of the present invention. Therefore, the specific configuration of elements and steps disclosed herein has been selected by the inventors merely to describe and illustrate examples of the present invention, and is not intended to limit the scope of the present invention or its protection, which is given the full scope of the appended claims and any equivalents thereof.

Claims

1. a first medical device having a first passive marker, the first passive marker being formed of a first material having a first magnetic susceptibility; a second medical device having a second passive marker, the second passive marker being formed of a second material having a second magnetic susceptibility, the second passive marker producing an image artifact under MRI; and A medical system useful for performing treatment under magnetic resonance imaging, comprising: The medical system, wherein the image artifact caused by the second passive marker is altered when the first passive marker overlaps the second passive marker under MRI.

2. The medical system of claim 1 , wherein the first magnetic susceptibility is the same as the second magnetic susceptibility.

3. The medical system of claim 2 , wherein the image artifact caused by the second passive marker is amplified when the first passive marker overlaps the second passive marker.

4. The medical system of claim 1 , wherein the first magnetic susceptibility is different from the second magnetic susceptibility.

5. The medical system of claim 4 , wherein the image artifact caused by the second passive marker is attenuated when the first passive marker overlaps the second passive marker.

6. The medical system of claim 1 , wherein the first material is the same as the second material.

7. The medical system of claim 1 , wherein the first material is different from the second material.

8. the first medical device comprises an elongate member, the first passive marker being disposed on the elongate member of the first medical device; The medical system of claim 1 , wherein the second medical device comprises an elongate member and the second passive marker is disposed on the elongate member of the second medical device.

9. The medical system of claim 8 , wherein the elongate member of the first medical device is formed of a third material different from the first material.

10. The medical system of claim 9 , wherein the elongate member of the second medical device is formed of a fourth material that is different from the second material.

11. The medical system of claim 10 , wherein the third material and the fourth material are titanium.

12. The medical system of claim 8 , wherein the first medical device and the second medical device can be used coaxially.

13. the first passive markers include a first plurality of passive markers, each marker in the first plurality of passive markers formed from the first material, each marker in the first plurality of passive markers producing an image artifact under MRI; the second passive markers include a second plurality of passive markers, each marker in the second plurality of passive markers formed from the second material, each marker in the second plurality of passive markers producing an image artifact under MRI; The medical system of claim 1 , wherein the image artifact caused by each marker in the second plurality of passive markers is altered when the first plurality of passive markers overlaps the second plurality of passive markers.

14. 2. The medical system of claim 1, wherein the first passive markers include a first plurality of passive markers, the first plurality of passive markers including a first subset of markers, a second subset of markers, and a third subset of markers, each marker in the first subset of markers formed of the first material, each marker in the second subset of markers formed of a third material having a third magnetic susceptibility, each marker in the third subset of markers formed of a fourth material having a fourth magnetic susceptibility, the first magnetic susceptibility being different from the third magnetic susceptibility and the fourth magnetic susceptibility, and the third magnetic susceptibility being different from the fourth magnetic susceptibility.

15. the second passive markers include a second plurality of passive markers, the second plurality of passive markers including a first subset of markers, a second subset of markers, and a third subset of markers, each marker in the first subset of markers of the second plurality of passive markers is formed from the second material, each marker in the second subset of markers of the second plurality of passive markers is formed from a fifth material having a fifth magnetic susceptibility, each marker in the third subset of markers of the second plurality of passive markers is formed from a sixth material having a sixth magnetic susceptibility, the second magnetic susceptibility is different from the fifth magnetic susceptibility and the sixth magnetic susceptibility, and the fifth magnetic susceptibility is different from the sixth magnetic susceptibility; 15. The medical system of claim 14, wherein each marker in the first subset of markers of the second plurality of markers produces an image artifact under MRI, each marker in the second subset of markers of the second plurality of markers produces an image artifact under MRI, and each marker in the third subset of markers of the second plurality of markers produces an image artifact under MRI.

16. the image artifact caused by each marker in the first subset of markers of the second plurality of passive markers is modified when the first subset of markers of the first plurality of passive markers overlaps the first subset of markers in the second plurality of passive markers; the image artifact caused by each marker in the second subset of markers of the second plurality of passive markers is altered when the second subset of markers of the first plurality of passive markers overlaps the second subset of markers in the second plurality of passive markers; 16. The medical system of claim 15, wherein the image artifacts caused by each marker in the third subset of markers of the second plurality of passive markers are altered when the third subset of markers of the first plurality of passive markers overlaps the third subset of markers in the second plurality of passive markers.

17. placing a patient in a magnetic resonance scanner; scanning a first portion of the patient using the magnetic resonance scanner, the magnetic resonance scanner having a first set of MR image parameters; acquiring a magnetic resonance image of the first portion of the patient; identifying tissue having predefined characteristics using the magnetic resonance images; selecting a procedure for treating the tissue based on the predefined characteristics; selecting a medical system comprising a first medical device and a second medical device to facilitate performance of the procedure; while the patient is positioned within the magnetic resonance scanner used to scan the first portion of the patient, inserting the medical system into a body passageway and to the tissue while scanning a second portion of the patient including the medical system and a first image artifact using the magnetic resonance scanner; acquiring a magnetic resonance image of the second portion of the patient including the medical system and the first image artifact; identifying the first image artifact in the MR image; identifying a position of the medical system within the body passageway; manipulating a position of the first medical device relative to the second medical device to modify the first image artifact to produce a modified image artifact; scanning a third portion of the patient including the medical system and the modified image artifact using the magnetic resonance scanner; acquiring a magnetic resonance image of the third portion of the patient including the medical system and the modified image artifact; modifying the first set of MR image parameters to a second set of MR image parameters based on the modified image artifacts; To provide treatment and A method for performing a treatment under magnetic resonance imaging, comprising:

18. the first medical device has a first marker, the first marker being a passive marker formed of a first material, the first material having a first magnetic susceptibility; 20. The method of claim 17, wherein the second medical device has a second marker, the second marker being a passive marker formed of a second material, the second material having a second magnetic susceptibility.

19. The method of claim 18 , wherein the first magnetic susceptibility is the same as the second magnetic susceptibility.

20. placing a patient in a magnetic resonance scanner; scanning a first portion of the patient using the magnetic resonance scanner, the magnetic resonance scanner having a first set of MR image parameters; acquiring a magnetic resonance image of the first portion of the patient; identifying tissue having predefined characteristics using the magnetic resonance images; selecting a procedure for treating the tissue based on the predefined characteristics; selecting a first medical device to perform performance of the procedure, the first medical device having a first marker; inserting the first medical device into a body passageway and to the tissue while scanning a second portion of the patient that includes a first image artifact caused by the first marker, while the patient is positioned within the magnetic resonance scanner used to scan the first portion of the patient, the first image artifact having a first set of characteristics; acquiring a magnetic resonance image of the second portion of the patient including the first image artifact; identifying the first image artifact in the MR image using the first set of characteristics; modifying the first set of MR image parameters to a second set of MR image parameters based on the identified first image artifact; To provide treatment and A method for performing a treatment under magnetic resonance imaging, comprising:

Images