Systems for body pathway navigation and visualization

Abstract

The present disclosure relates to systems and methods for enhancing navigation and visualization of body pathways. In particular, the systems and methods of the present disclosure provide enhanced navigation through the periphery of the lungs, as well as enhanced visualization within larger lung pathways.

Description

[0001] This application is a divisional application of application number 201880013438.X, application date 2018.2.26, and name “System for body pathway navigation and visualization”.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims priority under 35 USC §119 to U.S. Provisional Patent Application Serial No. 62 / 464,166, filed on February 27, 2017, the entire contents of which are incorporated by reference for all purposes. Technical Field

[0004] The present disclosure relates to systems and methods for enhancing navigation through body passages and improving visualization and sampling of target tissue. Background Art

[0005] Navigating and visualizing within body passages using ultrasound probes presents difficulties in preventing damage to the probe and optimizing visualization. For example, when clinical presentation indicates that a tissue biopsy within the pulmonary system is necessary, radial endobronchial ultrasound (R-EBUS) provides a minimally invasive option. The ultrasound component of such a lung tissue biopsy system is crucial for visualizing target nodules within the pulmonary passages. Ultrasonic energy can only propagate through materials with a certain density and refractive index, such as polymers, necessitating that the ultrasound probe extend beyond the distal end of the delivery catheter. Due to the size limitations of the lung periphery, the exposed portion of the ultrasound probe is often small and fragile and therefore easily damaged. The lack of a tapered / atraumatic leading edge on the exposed portion means that even a gentle collision along the wall of the pulmonary passage can cause the ultrasound probe to kink and / or break, requiring the introduction of a new device to continue the procedure. In addition, visualization of target nodules within larger pulmonary passages is often impaired by the presence of open space (e.g., air) between the ultrasound probe and the tissue wall, which obstructs / attenuates the propagation of the ultrasound signal.

[0006] Thus, various advantages may be realized by a system that allows for enhanced navigation through narrow body passages and improved visualization of target tissue within larger body passages. Summary of the Invention

[0007] The present disclosure, in its various aspects, provides advantages in medical fields, such as lung endoscopy, for sampling systems that can allow for enhanced navigation through body passages and improved visualization and sampling of target tissue. In various embodiments, the sampling system can include an end cap that protects the exposed portion of the ultrasound probe and enhances contact with the wall of the body passage and propagation of ultrasound signals to improve visualization of the target tissue.

[0008] In one aspect, the present disclosure relates to a system comprising an elongated member, which may include a first working channel and a second working channel defining respective first and second openings. An ultrasound probe may be positioned within the first working channel such that a distal portion of the ultrasound probe may extend distally beyond the distal end of the elongated member. An end cap may be attached to the distal end of the elongated member to enclose the distal portion of the ultrasound probe when the probe is extended beyond the first opening. A tissue sampling element may be slidably positioned within the second working channel. The first working channel may extend between a proximal end and a distal end of the elongated member to define a first opening. The second working channel may extend between the proximal end of the elongated member and an outer surface of the elongated member to define a second opening. The second working channel may define a ramped surface within the distal portion of the elongated member at the second opening. The end cap may include a hard plastic material. The end cap may be filled with a conductive material. The end cap may include an expandable member configured to move between a first configuration and a second configuration. The expandable member may be movable from the first configuration to the second configuration by flowing an inflation fluid into the expandable member. The expandable member can be moved from the second configuration to the first configuration by allowing inflation fluid to flow from an interior region of the expandable member. The ultrasound probe can be fixed within the first working channel. The ultrasound probe can be slidable within the first working channel. The end cap can be attached to a circumference of the distal end of the elongated member. The end cap can be attached around (e.g., surrounding) the first opening of the distal end of the elongated member.

[0009] In another aspect, the present disclosure relates to a system including an elongated member that may include a first working channel and a second working channel defining respective first and second openings. An ultrasound probe may be positioned within the first working channel such that a distal portion of the ultrasound probe may extend distally beyond the distal end of the elongated member. An end cap may be attached to the distal portion of the ultrasound probe. A tissue sampling element may be slidably positioned within the second working channel. The first working channel may extend between a proximal end and a distal end of the elongated member to define a first opening. The second working channel may extend between the proximal end of the elongated member and an outer surface of the elongated member to define a second opening. The second working channel may define a ramped surface within the distal portion of the elongated member at the second opening. The end cap may include an expandable member configured to move between a first configuration and a second configuration. The expandable member may be movable from the first configuration to the second configuration by allowing an inflation fluid to flow into the interior of the expandable member. The expandable member may be movable from the second configuration to the first configuration by allowing an inflation fluid to flow out of the interior region of the expandable member. The ultrasound probe may be fixed within the first working channel. The ultrasound probe may be slidable within the first working channel.

[0010] In another aspect, the present disclosure relates to a method comprising advancing a system into a body passage, wherein the system may include an elongated member, an ultrasound probe disposed within a first working channel of the elongated member, and an expandable member attached to a distal end of the elongated member. The distal portion of the ultrasound probe may extend distally beyond the distal end of the elongated member. The expandable member may be attached to the distal end of the elongated member to enclose the distal portion of the ultrasound probe. The expandable member may be moved from a first configuration to a second configuration so that the expandable member contacts a wall of the body passage adjacent to target tissue. An ultrasound image of the body passage and / or the target tissue may be obtained using the ultrasound probe. The expandable member may be advanced through the body passage in the second configuration. The method may further include advancing a tissue sampling element distally beyond the second opening into the target tissue, such that a portion of the target tissue is captured within the lumen of the tissue sampling element. The system may be withdrawn from the body passage, whereupon a tissue sample captured within the lumen of the tissue sampling element may be made available for analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Non-limiting examples of the present disclosure are described with reference to the accompanying drawings, which are schematic and not intended to be drawn to scale. In the drawings, each identical or nearly identical component is generally represented by a single reference numeral. For clarity, not every component is labeled in every figure, and not every component of every embodiment of the present disclosure is shown, where illustration is not necessary for a person skilled in the art to understand the present disclosure. In the drawings:

[0012] Figures 1A-1B A schematic diagram of a tissue biopsy system according to an embodiment of the present disclosure is provided.

[0013] Figures 2A-2E A schematic diagram of a tissue biopsy system according to another embodiment of the present disclosure is provided.

[0014] Figures 3A-3B A schematic diagram of a tissue biopsy system according to another embodiment of the present disclosure is provided.

[0015] Figures 4A-4B A schematic diagram of a tissue biopsy system according to another embodiment of the present disclosure is provided.

[0016] It should be noted that the drawings are intended only to illustrate representative or exemplary embodiments of the present disclosure. Therefore, the drawings should not be considered to limit the scope of the present disclosure. The present disclosure will now be described in more detail with reference to the drawings. DETAILED DESCRIPTION

[0017] Before describing the present disclosure in further detail, it should be understood that the present disclosure is not limited to the specific embodiments described and is therefore subject to change. It should also be understood that the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope beyond the appended claims. Unless otherwise defined, all technical terms used herein have the same meaning as those of ordinary skill in the art to which the present disclosure belongs. Finally, although the embodiments of the present disclosure are described with specific reference to enhanced navigation through pulmonary pathways and improved visualization and sampling of pulmonary nodules, the systems and methods disclosed herein can be used for imaging and obtaining biopsy samples in a variety of body lumens, including, for example, the heart, vascular system, circulatory system, gastrointestinal (GI) tract, stomach, esophagus, urinary system, etc. In various embodiments, in addition to the biopsy needle, the catheter end cap can also be adapted for use with a variety of tissue sampling tools (e.g., grasping or cutting elements).

[0018] As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the terms "include" and / or "comprise" or "contain" and / or "have" when used herein specify the presence of the features, regions, steps, elements and / or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components and / or groups thereof.

[0019] As used herein, the term "distal" refers to the end farthest from the medical professional when the device is introduced into a patient, and the term "proximal" refers to the end closest to the medical professional when the device is introduced into a patient.

[0020] The present disclosure generally provides a tissue biopsy system for enhancing navigation and visualization of large and small body passages. In particular, the disclosed tissue biopsy system generally includes an elongated member having a working channel and an end cap, the working channel being configured to accommodate a corresponding tissue sampling element and an ultrasound probe, the end cap being configured to protect / support an exposed portion of the ultrasound probe and maintain direct contact between the tissue wall and body passages of various sizes and / or shapes. In various embodiments, the ultrasound probe can be fixedly or slidably disposed within a first working channel of the elongated member. Furthermore, a distal portion of the ultrasound probe (including an ultrasound transducer) can extend through a first opening of the elongated member and distally beyond a distal end of the elongated member.

[0021] Reference Figure 1AIn one embodiment, a tissue biopsy system of the present disclosure may include an elongated member 110 (e.g., a catheter, a delivery device, etc.) including a first working channel 114 and a second working channel 116 defining respective first and second openings 115, 117. The first and second openings 115, 117 are not limited to generally circular and elliptical shapes, respectively, but may include a variety of other shapes and / or configurations. The first working channel 114 may extend between a proximal end (not shown) and a distal end 112 of the elongated member 110 to define the first opening 115. The second working channel 116 may extend between a proximal end (not shown) and an outer surface 113 of the elongated member 110 to define the second opening 117. The second working channel 116 may form an inclined or ramped surface 118 within a distal portion of the elongated member 110 at the second opening 117. The ramped surface 118 may have an angle of approximately 5 degrees to approximately 10 degrees relative to the longitudinal axis of the elongated member 110, and may have any angle therebetween. The second working channel 116 may be configured to slidably receive a tissue sampling element 150 (eg, a biopsy needle, etc.).

[0022] The first working channel 114 can be configured to receive an ultrasound probe 120 having an ultrasound transducer 124 rotatably disposed on its distal end. In one embodiment, the ultrasound probe 120 can be fixedly disposed within the first working channel 114. In another embodiment, the ultrasound probe 120 can be slidably disposed within the first working channel. A distal portion 122 of the ultrasound probe 120 (including the ultrasound transducer 124) can extend through the first opening 115 and distally beyond the distal end 112 of the elongated member 110.

[0023] The end cap 130 can be attached to the distal end 112 of the elongated member 110 to enclose and protect the ultrasonic transducer 124. In one embodiment, the end cap 130 may comprise a polymer material having a suitable thickness and refractive index to allow ultrasonic energy to propagate through without attenuation, including but not limited to high-density polyethylene (HDPE). For example, the end cap 130 may comprise a hard plastic material having an atraumatic end (e.g., a conical, bullet-shaped shape, etc.) to navigate through tortuous and narrow lung passages. The end cap 130 can be permanently attached to the distal end 112 of the elongated member 110 by suitable welding, soldering, brazing, adhesives, epoxies, glues, and / or resins. Additionally or alternatively, the end cap 130 can be reversibly attached to the distal end 112 of the elongated member 110 by at least one of a snap fit, a press fit, an interference fit, and / or a compression fit. The end cap 130 can define an open (e.g., hollow) interior space that can be filled with a conductive material 140 (e.g., polyethylene glycol (PEG), petroleum jelly, carbowax, saline, etc.), which eliminates the need to rinse the ultrasound probe with saline throughout the medical procedure. In embodiments where the end cap 130 is reversibly attached to the elongated member 110, the end cap can be loaded or reloaded with the conductive material prior to use. The end cap 130 can have an outer diameter approximately equal to the outer diameter of the elongated member 110 to provide radial (e.g., 360 degrees) contact with the tissue wall of the lung passageway. The ability of the end cap 130 to directly contact the complete inner circumference of the larger lung passageway can provide improved ultrasound images by removing voids (e.g., air) that hinder / attenuate ultrasound energy from contacting / penetrating the tissue wall. Additionally, the atraumatic profile and low friction outer surface can allow the end cap 130 to maintain full circumferential contact with the tissue wall as the tissue biopsy system is advanced into the narrower lung periphery. Reference Figure 1B , tissue sampling element 150 can be advanced distally along ramped surface 118 of second working channel 116 such that tissue sampling element 150 deflects (e.g., bends) away from the longitudinal axis of elongated member 110 without contacting end cap 130 upon exiting second opening 117.

[0024] Reference Figure 2AIn one embodiment, the distal end 112 of the elongated member 110 may include an end cap 230 (e.g., an expandable member, a balloon, etc.) comprising one or more elastomeric and / or compliant materials having a suitable thickness and refractive index to allow for unattenuated propagation of ultrasonic energy. By way of non-limiting example, semi-compliant materials may include polyester elastomers (e.g., Arnitel, Hytrel, etc.). By way of non-limiting example, compliant materials may include latex and silicone. As will be understood by those skilled in the art, end caps formed from compliant materials are capable of indefinite expansion (e.g., not having a fixed final diameter). For example, these materials may have a compliance preferably in the range of 10% to 800%, more preferably in the range of 50% to 200%. The end cap 230 may be permanently attached to the distal end 112 of the elongated member 110 using a suitable adhesive, epoxy, glue, and / or resin. Alternatively, the end cap 230 can be reversibly attached to the distal end 112 of the elongated member 110 by at least one of a snap fit, a press fit, an interference fit, and / or a compression fit. The end cap 230 can be configured to move between a first configuration (e.g., collapsed, pre-inflated, etc.) and one or more second configurations (e.g., expanded, inflated, etc.) by flowing an inflation fluid (e.g., saline, gel, etc.) between an external fluid source (not shown) and the interior region 236 of the end cap. In one embodiment, the elongated member 110 can include a dedicated inflation fluid delivery lumen 128 extending between the proximal end (not shown) and the distal end 112 to fluidly connect the external fluid source with the interior region 236. Alternatively, the inflation fluid can flow between the external fluid source and the interior region 236 of the end cap 230 via the first working channel 114 of the elongated member 110 in the auxiliary space surrounding the ultrasound probe 120.

[0025] In the first configuration, the end cap 230 can be folded or collapsed around the distal portion 122 of the ultrasound probe 120 to provide a reduced profile (e.g., a smaller diameter) so that the tissue biopsy system can be passed through a working channel of a medical device (e.g., a bronchoscope, etc.). In addition, the reduced profile of the end cap 230 can provide structural support to the distal portion 122 of the ultrasound probe 120 to prevent kinking and / or bending as the tissue biopsy system is advanced through the pulmonary passageway.

[0026] The end cap having a compliant or semi-compliant material may allow the end cap 230 to be adjusted from a first configuration ( Figure 2A ) moves to multiple second configurations depending on the specific size of the lung passages ( Figures 2B to 2E ). As the tissue biopsy system is positioned within a portion of the pulmonary passageway to be visualized, inflation fluid may be introduced into the interior region 236 of the end cap 230 until the outer surface of the end cap 230 is in direct contact with the inner circumference of the pulmonary passageway. Figures 2B to 2EEnd cap 230 is shown expanded in a generally uniform or symmetrical configuration, but a compliant or semi-compliant material may allow end cap 230 to expand asymmetrically to establish full contact with an irregular or non-uniformly shaped body passageway (e.g., a bifurcation, etc.). The atraumatic profile and low-friction outer surface of end cap 230 maintain full circumferential contact with the tissue wall as the tissue biopsy system is advanced into the narrower periphery of the lung. Inflation fluid may be introduced into or removed from interior region 236 of end cap 230 as needed to maintain contact with the tissue wall of the lung passageway throughout the medical procedure. Regardless of the level of inflation of end cap 230, tissue sampling element 150 may be advanced distally along ramped surface 118 of second working channel 116, causing tissue sampling element 150 to deflect (e.g., bend) away from the longitudinal axis of elongated member 110 without contacting end cap 230 upon exiting second opening 117.

[0027] In another embodiment, the end cap 230 may include one or more non-compliant materials configured to move from a first configuration to a second configuration of a single / fixed diameter. By way of non-limiting example, the non-compliant material may include polyethylene terephthalate (PET). Compared to compliant or semi-compliant materials, the non-compliant material may provide increased structural support to the distal portion 122 of the ultrasound probe 120 when the end cap 230 is in the first configuration. The non-compliant material may also provide increased structural support when in the second configuration, for example, to better control the forces applied to the inner circumference of the pulmonary passageway and / or to resist penetration due to accidental contact with the tissue sampling element 150.

[0028] Reference Figures 3A to 3B In another embodiment, the tissue biopsy system of the present disclosure may include an end cap 330 having a compliant, semi-compliant, or non-compliant material attached to the distal portion 122 of the ultrasound probe 120. The end cap 330 may be configured in a first configuration ( Figure 3A ) and the second configuration ( Figure 3B). For example, the inflation fluid can flow between an external fluid source and the interior region 336 of the end cap 330 through a dedicated fluid delivery lumen (not shown) that extends along or through the ultrasound probe 120. Alternatively, the end cap 330 can be attached to the distal end 112 of the elongated tubular member 110 around the first opening 115, such that the inflation fluid can flow between the external fluid source and the interior region 336 of the end cap 330 through the first working channel 114 of the elongated member 110 in the auxiliary space around the ultrasound probe 120. In a first configuration, the end cap 330 can be folded or collapsed around the distal portion 122 of the ultrasound probe 120 to provide a reduced profile (e.g., a smaller diameter) so that the tissue biopsy system can be passed through a working channel of a medical device (e.g., a bronchoscope, etc.). In addition, the end cap 330 can provide structural support to the distal portion 122 of the ultrasound probe 120 to prevent kinking and / or bending as the tissue biopsy system is advanced through the pulmonary passageway.

[0029] Once the tissue biopsy system is positioned within a portion of the pulmonary passageway that the medical professional wishes to visualize, inflation fluid can be introduced into the interior region 336 of the end cap 330 until the outer surface of the end cap is in direct contact with the inner circumference of the pulmonary passageway. As described above, the end cap 330, comprising a compliant or semi-compliant material, can expand asymmetrically to establish full contact with an irregularly or non-uniformly shaped body passageway. The atraumatic profile and low-friction outer surface of the end cap 330 maintain full circumferential contact with the tissue wall as the tissue biopsy system is advanced into the narrower pulmonary periphery. Inflation fluid can be introduced into or removed from the interior region 336 of the end cap 330 as needed to maintain contact with the tissue wall of the pulmonary passageway throughout the medical procedure. Regardless of the end cap's inflation level, the tissue sampling element 150 can be advanced distally along the ramped surface 118 of the second working channel 116, causing the tissue sampling element 150 to deflect (e.g., bend) away from the longitudinal axis of the elongated member 110 without contacting the end cap 330 upon exiting the second opening 117.

[0030] Reference Figures 4A-4B In one embodiment, the tissue biopsy system of the present disclosure may include two or more (compliant, semi-compliant, or non-compliant) end caps 430 attached to the distal portion 122 of the ultrasound probe 120. Compared to a single end cap (such as Figure 3A Configuration), the plurality of end caps 430 may be in a first configuration ( Figure 4A) to provide additional structural support to the distal portion 122 of the ultrasound probe 120. Furthermore, each of the end caps 430 can include a separate / dedicated fluid delivery lumen (not shown) such that each end cap can be independently moved between a first configuration and a second configuration as needed to maintain full circumferential contact with an irregular or non-uniformly shaped body passageway. For example, an inflation fluid can flow between an external fluid source and an interior region of the end cap 430 through a separate, dedicated fluid delivery lumen (not shown) that extends along or through the ultrasound probe 120.

[0031] In use and by way of example, the biopsy system disclosed herein can be advanced into a body passageway (e.g., the periphery of a lung) such that the end cap 130, 230, 330, 430 is in radial (e.g., 360-degree) contact with a tissue wall of the body passageway. Upon identifying target tissue within or adjacent to the tissue wall, the tissue sampling element 150 can be advanced distally along the ramped surface 118 of the second working channel 116 such that the tissue sampling element 150 deflects (e.g., bends) away from the longitudinal axis of the elongated member 110 and into the target tissue without contacting the end cap 130, 230, 330, 430. The biopsy system can then be removed from the body passageway, and the target tissue captured within the lumen of the tissue sampling element 150 can be removed for analysis. Alternatively, tissue sampling element 150 may be retracted proximally along ramped surface 118 of second working channel 116, the biopsy system advanced through the body passageway to one or more additional target tissue sites, and tissue sampling element 150 advanced distally to capture additional target tissue for analysis.

[0032] Although the end caps of this disclosure have been described with reference to Figures 1A to 4B Although described with reference to the specific embodiments shown, various embodiments of the disclosed tissue biopsy system may include any number of compliant, semi-compliant, or non-compliant end caps that are symmetrically or asymmetrically attached to the distal end 112 of the elongated member 110 or the distal portion 122 of the ultrasound probe 120. The inner or outer surface of the end cap (such as any of the disclosed end caps 230, 330, 430) may include one or more pressure sensors to ensure that the end cap does not over-expand, thereby causing expansion of the lung passages. Similarly, Figures 1A-1BThe end cap 130 in the embodiment may include one or more pressure sensors to ensure that no excessive force is applied to the tissue wall when the tissue biopsy system is advanced into the periphery of the lung. In addition to providing improved visualization of the lung passageway, any of the disclosed end cap configurations 130, 230, 330, 430 may provide another benefit by stabilizing and / or securing the tissue biopsy system within the body passageway, thereby minimizing longitudinal and / or rotational movement when the tissue sampling element is actuated, thereby reducing the likelihood that the tissue sampling element will lose the target tissue. An additional benefit of any of the disclosed end cap configurations is the ability to place a portion of the lung passageway adjacent to the target tissue under tension, such that the target tissue is at least partially secured for more precise / accurate biopsy by the tissue sampling element.

[0033] The medical devices of the present disclosure are not limited to bronchoscopes and may include a variety of medical devices for accessing body passages, including, for example, catheters, ureteroscopes, duodenoscopes, colonoscopes, arthroscopes, cystoscopes, hysteroscopes, etc. Finally, although the embodiments of the present disclosure have been described for use with a bronchoscope, the tissue biopsy system of the present disclosure may be positioned within a patient without an accompanying medical device.

[0034] In accordance with the content of the present disclosure, all devices and / or methods disclosed and claimed herein can be implemented and executed without undue experimentation. Although the devices and methods of the present disclosure have been described in terms of preferred embodiments, it is obvious to those skilled in the art that modifications may be made to the devices and / or methods and the steps or sequence of steps of the methods described herein without departing from the concept, essence and scope of the present disclosure. It is obvious to those skilled in the art that all such similar substitutes and modifications are deemed to be within the essence, scope and concept of the present disclosure as defined by the appended claims.

Claims

1. A system comprising: an elongated member comprising first and second working channels defining respective first and second openings, wherein the second working channel extends between a proximal end of the elongated member and an outer surface of the elongated member to define the second opening; an ultrasound probe disposed within the first working channel, wherein a distal portion of the ultrasound probe is extendable distally beyond the distal end of the elongated member; and An end cap is attached to the distal end of the elongated member to enclose the distal portion of the ultrasound probe when the ultrasound probe is extended out of the first opening.

2. The system of claim 1, further comprising a tissue sampling element slidably disposed within the second working channel. 3 . The system of claim 1 , wherein the first working channel extends between a proximal end and the distal end of the elongated member to define the first opening.

4. The system of any one of claims 1 to 3, wherein the end cap structurally supports the ultrasound probe when the ultrasound probe is extended outside the first opening.

5. The system of any one of claims 1 to 3, wherein the second working channel defines a ramp surface within the distal portion of the elongated member at the second opening.

6. The system of any one of claims 1 to 3, wherein the end cap comprises high density polyethylene (HDPE).

7. The system of any one of claims 1 to 3, wherein the end cap comprises an expandable member.

8. The system of claim 7, wherein the end caps are fillable with a conductive material.

9. The system of claim 7, wherein the expandable member is configured to move between a first configuration and a second configuration.

10. The system of claim 9, wherein the expandable member is movable from the first configuration to the second configuration by flowing an inflation fluid into an interior of the expandable member.

11. The system of claim 9, wherein the expandable member is movable from the second configuration to the first configuration by flowing an inflation fluid from an interior region of the expandable member.

12. The system of any one of claims 1 to 3, wherein the ultrasound probe is fixed or slidable within the first working channel.

13. A system comprising: an elongated member comprising first and second working channels defining respective first and second openings, wherein the second working channel extends between a proximal end of the elongated member and an outer surface of the elongated member to define the second opening; an ultrasound probe disposed within the first working channel, wherein a distal portion of the ultrasound probe is extendable distally beyond the distal end of the elongated member; and An end cap is attached to the distal portion of the ultrasound probe, wherein the end cap encloses the distal portion of the ultrasound probe when the ultrasound probe is extended distally beyond the distal end of the elongated member.

14. The system of claim 13, wherein the end cap comprises high density polyethylene (HDPE).

15. The system of claim 13, surrounding and structurally supporting the ultrasound probe distally beyond the distal end of the elongated member.

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