Introduction sheath with displacement sensor

Abstract

The introducer sheath may include a displacement sensor that detects displacement of the catheter within the introducer sheath. The displacement sensor may employ induction-based, optical-based, mechanical-based, or other techniques to detect displacement. The displacement sensor may include a display on which the detected displacement is presented to the clinician. The displacement sensor may allow the clinician to provide a user input to reset the displacement.

Description

【Technical Field】 【0001】 The present invention relates to an introducer sheath. 【Background Art】 【0002】 An introducer sheath is a component of various vascular access systems. The introducer sheath is often used to introduce a catheter into a patient's vascular system. For example, in the Seldinger technique, a sharp hollow needle is first used to puncture the vascular system. Next, a guide wire can be inserted into the vascular system through the lumen of the needle. Then, the needle can be withdrawn while leaving the guide wire positioned within the vascular system. Next, an introducer sheath, which may include a dilator, can be passed into the vascular system over the guide wire. With the introducer sheath positioned within the vascular system, the guide wire can be withdrawn. The introducer sheath is typically held in this position so that a catheter or other device can be introduced into the patient's vascular system to perform procedures such as angioplasty, stent placement, thermal ablation, embolization, biopsy, and the like. 【0003】 FIG. 1 provides an example of an introducer sheath assembly 100, although many different configurations and variations exist. The introducer sheath assembly 100 includes an introducer sheath 110 and a dilator 120 that can be initially assembled to the introducer sheath 110. The dilator 120, which extends from a proximal end 121 to a tapered distal end 122, generally functions to facilitate insertion of the introducer sheath 110 into the patient's vascular system. The introducer sheath 110 can have a shaft 111 that extends distally from a hub 112. When assembled, the distal end 122 of the dilator 120 extends distally from the shaft 111 of the introducer sheath 110. A handle 113 can extend from the hub 112 to provide a gripping surface. In a typical use case, after the introducer sheath 110 is inserted into the patient's vascular system, the dilator 120 is withdrawn, whereby a catheter or other device can be inserted using the introducer sheath 110. 【0004】 When introducing a catheter (or other device) into a patient's vascular system using an introduction sheath, it is common practice to use fluoroscopy to confirm the catheter's position and, if necessary, manipulate it to the desired location. For example, when performing angioplasty, it is crucial to position the catheter so that the balloon aligns with the occluded portion of the artery or vein. Given that fluoroscopy exposes both the patient and the clinician to harmful radiation, it is generally desirable to minimize its use during the procedure. However, many procedures require precise catheter placement, which typically necessitates the long-term use of fluoroscopy. Furthermore, once the catheter is in place, it is not uncommon for it to shift, and repeated fluoroscopy may be necessary to reposition the catheter. 【0005】 The subject matter claimed herein is not limited to embodiments that resolve any shortcomings or embodiments that operate only in the environments described above. Rather, this background art is provided merely to illustrate an example of the technical area in which some of the embodiments described herein can be carried out. [Overview of the project] 【0006】 This disclosure generally relates to an induction sheath including a displacement sensor for detecting the displacement of a catheter within the induction sheath. The displacement sensor may employ induction-based, optical-based, mechanical-based, or other techniques to detect the displacement. The displacement sensor may include a display on which the detected displacement is presented to the clinician. The displacement sensor may allow the clinician to provide user input to reset the displacement. 【0007】 In some embodiments, the introduction sheath may include a hub that forms a proximal opening to a lumen, a shaft that extends distally from the hub so that the lumen extends through the shaft to form a distal opening, and a displacement sensor. In some embodiments, the displacement sensor may include a sensor unit arranged to detect the displacement of the catheter within the lumen and output a signal representing the detected displacement. In some embodiments, the displacement sensor may include a control unit configured to receive the signal from the sensor unit and maintain the displacement value based on the signal. In some embodiments, the control unit may be configured to output the displacement value. In some embodiments, the displacement sensor may include a display on which the displacement value can be displayed. 【0008】 In some embodiments, the sensor unit may be at least partially positioned around the shaft. In some embodiments, the sensor unit may include an inductive element, and the signal representing the detected displacement may represent a change in inductance. In some embodiments, the sensor unit may include one or more optical sensors, and the signal representing the detected displacement may represent light received by one or more optical sensors. In some embodiments, the sensor unit may include one or more rollers, and the signal representing the detected displacement may represent the rotation of one or more rollers. 【0009】 In some embodiments, the displacement sensor may include an input element, and the control unit may be configured to reset the displacement value when the input element is activated. In some embodiments, the input element may be a display, and the displacement value may be displayed on the display. In some embodiments, the control unit may output an alarm in response to a change in the displacement value. In some embodiments, the displacement sensor may include a wireless circuit, and the displacement value may be transmitted to an external device via the wireless circuit. 【0010】 In some embodiments, the introduction sheath may include a hub that forms a proximal opening to a lumen, a shaft that extends distally from the hub so that the lumen extends through the shaft to form a distal opening, and a displacement sensor. In some embodiments, the displacement sensor may include a sensor unit arranged to detect the displacement of the catheter within the lumen and output a signal representing the detected displacement. In some embodiments, the displacement sensor may include a control unit configured to receive the signal from the sensor unit and maintain the displacement value based on the signal. In some embodiments, the displacement sensor may include a display on which the control unit displays the displacement value. 【0011】 In some embodiments, the sensor unit may include an inductive element positioned adjacent to the lumen, and the signal representing the detected displacement may represent a change in the inductance of the inductive element caused when the catheter is displaced within the lumen. In some embodiments, the catheter may be placed inside another catheter when the catheter is displaced within the lumen. 【0012】 In some embodiments, the sensor unit may include one or more optical sensors, and the signal representing the detected displacement may represent light reflected from markings on the catheter when the catheter is displaced within the lumen. In some embodiments, the sensor unit may include one or more rollers, and the signal representing the detected displacement may represent rotation of one or more rollers caused by the catheter when the catheter is displaced within the lumen. 【0013】 In some embodiments, the control unit may be configured to reset the displacement value in response to user input. In some embodiments, the user input may be received via a display or input element. 【0014】 In some embodiments, the introduction sheath may include a hub that forms a proximal opening to a lumen, a shaft that extends distally from the hub so that the lumen extends through the shaft to form a distal opening, and a displacement sensor incorporated into the shaft and having a display. In some embodiments, the displacement sensor may be configured to calculate a displacement value when the catheter is displaced within the lumen and to display the displacement value on the display. In some embodiments, the displacement sensor may calculate the displacement value based on the change in inductance caused by the catheter as it is displaced within the lumen, the light reflected by the catheter as it is displaced within the lumen, or the rotation caused by the catheter as it is displaced within the lumen. In some embodiments, the displacement sensor may be configured to reset the displacement value in response to user input. 【0015】 It should be understood that the above general description and the following detailed description are illustrative and for illustrative purposes only, and do not limit the claimed invention. It should be understood that various embodiments are not limited to the configurations and means shown in the figures. It should also be understood that embodiments may be combined, or other embodiments may be used, and structural modifications may be made without departing from the scope of the various embodiments of the invention, unless otherwise claimed. Accordingly, the following detailed description should not be interpreted as restrictive. [Brief explanation of the drawing] 【0016】 Exemplary embodiments are described and explained in more specific and detail with reference to the accompanying drawings. [Figure 1] Figure 1 shows an example of a prior art sheath assembly. [Figure 2] Figure 2 shows examples of introduction sheath assemblies with displacement sensors according to several embodiments. [Figure 3A]Figure 3A is a cross-sectional view showing an introduction sheath with a displacement sensor according to several embodiments. [Figure 3B] Figure 3B is a cross-sectional view showing an introduction sheath with a displacement sensor according to several embodiments. [Figure 4A] Figure 4A is a cross-sectional view showing another introduction sheath with a displacement sensor according to several embodiments. [Figure 4B] Figure 4B is a cross-sectional view showing another introduction sheath with a displacement sensor according to several embodiments. [Figure 5A] Figure 5A is a cross-sectional view showing another introduction sheath having a displacement sensor according to several embodiments. [Figure 5B] Figure 5B is a cross-sectional view showing another introduction sheath with a displacement sensor according to several embodiments. [Figure 6A] Figure 6A provides examples of how an introduction sheath with a displacement sensor may be employed in several embodiments. [Figure 6B] Figure 6B provides examples of how an introduction sheath with a displacement sensor may be employed in several embodiments. [Figure 6C] Figure 6C provides examples of how an introduction sheath with a displacement sensor may be employed in several embodiments. [Figure 6D] Figure 6D provides examples of how an introduction sheath with a displacement sensor may be employed in several embodiments. [Modes for carrying out the invention] 【0017】 Embodiments of the present disclosure cover many different types and configurations of intravenous catheter systems including introduction sheaths, introduction sheath assemblies, and introduction sheaths. For example, any introduction sheath may integrate a displacement sensor according to several embodiments. 【0018】 FIG. 2 shows an example of an introducer sheath assembly 200 having an introducer sheath 210 that incorporates a displacement sensor 230, according to some embodiments. The introducer sheath assembly 200 may have components similar to those of the introducer sheath assembly 100 described in the background. For example, these components include an introducer sheath 210 having a shaft 211 that extends to a distal end 210a, a hub 212 disposed at a proximal end 210b, and a handle 213 that extends from the hub 212. The components may also include an expander 220 having a proximal end 221 and a distal end 222. However, note that an introducer sheath configured according to some embodiments need not include, incorporate, or otherwise utilize an expander or any other device. Thus, FIG. 2 should be viewed as an example of how the displacement sensor 230 can be integrated into one of many different types of introducer sheaths that may be available. 【0019】 FIGS. 3A and 3B are partial cross-sectional side views showing how the displacement sensor 230 can be integrated into the introducer sheath 210 and an example of various components that the displacement sensor 230 may include in some embodiments. FIG. 3A represents the introducer sheath 210 when a catheter (or other device) has not yet been inserted through the introducer sheath 210, and FIG. 3B represents the introducer sheath 210 when a guide catheter 310 and a microcatheter 311 have been inserted through the introducer sheath 210. In this context, a "guide catheter" should be interpreted as a catheter that can be used to guide the insertion of other devices such as a microcatheter or a guide wire. Thus, the microcatheter 311 can also be regarded as representing a guide wire or other device that can be inserted through the guide catheter 310. Also, FIG. 3B shows an example where both the guide catheter 310 and the microcatheter 311 are inserted into the introducer sheath 210, but the examples depicted should not be considered to be limited to such use cases. 【0020】 The displacement sensor 230 may include a housing 231 that is coupled to, integrated with, or disposed along the shaft 211 of the introduction sheath 210. In the depicted example, the housing 231 is disposed adjacent to the hub 212, but in some embodiments, it may be disposed at other locations including on the hub 212 or distally spaced from the hub 212. In FIGS. 3A and 3B, various components are shown as being disposed on or within the housing 231. However, in some embodiments, not all of the depicted components need to be included in the displacement sensor 230. In the depicted embodiment, the displacement sensor 230 includes a sensor unit 232 that may be disposed at least partially around or adjacent to the shaft 211 and may have an induction element 300 (e.g., an electric coil) disposed on, within, or adjacent to the sidewall of the shaft 211. Thus, FIGS. 3A and 3B represent embodiments where the displacement sensor 230 is an induction-based displacement sensor. To enable induction-based displacement sensing, catheters, micro-catheters, guide wires, etc. having such displacement sensing may include metal. 【0021】 The displacement sensor 230 may also include a control unit 234 electrically coupled to the sensor unit 232. The control unit 234 may be configured to receive signals from the sensor unit 232 and, based on such signals, detect the displacement of a catheter or other device within the lumen 211a of the shaft 211. For example, either or both of the guide catheter 310 and the microcatheter 311 may include an element that modifies the inductance of the inducting element 300 as an element passes over it. In some embodiments, these elements may be in the form of a metal (e.g., nickel-titanium, or nitinol, wire) embedded in the guide catheter 310, the microcatheter 311, or any other catheter that may be compatible with the introduction sheath 210. The control unit 234 may be configured to detect the variation in the inductance of the inducting element 300 or to receive signals generated by the sensor unit 232 representing such variation, thereby detecting the direction in which the guide catheter 310, the microcatheter 311, or another catheter has moved within the shaft 211. The control unit 234 may also be configured to store one or more values ​​representing the detected displacement (or "displacement value"). 【0022】 In some embodiments, the displacement sensor 230 may include a display 233, which may be positioned on the outer surface of the housing 231 so that it is visible during use of the insertion sheath 210. For example, the display 233 may be oriented upward when the insertion sheath 210 is inserted into the patient's vascular system. Any type of display, such as an LED or LCD, can be used. The display 233 may be electrically coupled to a control unit 234 and may receive a display signal containing information representing the current displacement value. That is, the control unit 234 may cause the display 233 to display the displacement value. The control unit 234 may also cause other information, such as insertion speed or a timer, to be displayed on the display 233. 【0023】 In some embodiments, the displacement sensor 230 may include a wireless circuit 235 (e.g., Bluetooth or Wi-Fi circuit) that the control unit 234 can use to wirelessly transmit displacement values ​​or other information to one or more other systems (e.g., on a remote display monitored by a clinician, to display the displacement on augmented reality glasses worn by the clinician during a procedure, to a memory system, etc.). In some embodiments, the wireless circuit 235 may also allow the control unit 234 to receive communications from one or more other systems. In some embodiments, such communications may include communications defining characteristics of the catheter or other device from which the displacement is detected (e.g., the distance at which elements are separated), communications defining operating modes, communications providing updated firmware, etc. Not shown, but in some embodiments, the displacement sensor 230 may optionally or additionally include circuits for transmitting or receiving communications / information via wired connections. In some embodiments, the displacement sensor 230 may include an input element (or multiple elements) 236 (e.g., a button, switch, sensor, touchscreen, etc.) for providing manual user input to the control unit 234. In some embodiments, the input element 236 may function to allow the user to reset (or set) the displacement value. In some embodiments, the input element 236 may be incorporated into the display 233 (for example, when the display 233 is a touchscreen). Not shown, the displacement sensor 230 may also include a power supply (e.g., a battery) to power various components. 【0024】 As described above, if the introduction sheath 210 includes a displacement sensor 230 having an inductive element 300, and the catheter includes an element that changes the inductance of the inductive element 300 (e.g., a metallic element that responds to the magnetic field generated by the inductive element 300), then any catheter displacement can be detected as it passes through the shaft 211. For example, if the guide catheter 310 includes elements spaced (or patterned) at 1 cm intervals, the control unit 234 may be configured to increase or decrease the displacement value of the guide catheter 310 by 1 cm each time the control unit 234 detects a change in inductance indicating an element passing through the inductive element 300. Whether the control unit 234 increases or decreases the displacement value may be based on a known profile of the changed inductance. In other words, the control unit 234 can detect from the profile of the changed inductance whether the guide catheter 310 is inserted into or withdrawn from the shaft 211. Furthermore, using the known profile, the control unit 234 can detect displacement at a high level of granularity (e.g., mm increments). 【0025】 When tracking / calculating this displacement, the control unit 234 outputs a display signal to the display 233 to display the displacement to the user. Therefore, assuming that the displacement value is set to zero before the guide catheter 310 is inserted into the introduction sheath 210, and the user wishes to insert the guide catheter to a depth of 10 cm, the user may look at the display 233 while inserting the guide catheter 310, and may stop inserting the guide catheter 310 when the display 233 reflects a displacement value of 10 cm. A similar process may be employed when inserting a microcatheter 311 through the guide catheter 310, or when inserting any other compatible catheter. 【0026】 In some embodiments, to facilitate the relative positioning of the catheter, the user may activate the input element 236 to zero out (or reset) the displacement value by further inserting the catheter or inserting another catheter. For example, after inserting the guide catheter 310 to a desired depth, the user may activate the input element 236 to zero out the displacement value and then insert the microcatheter 311 through the guide catheter 310. Once the microcatheter 311 is inserted, the control unit 234 can detect the displacement of the microcatheter 311 based on a signal received from the sensor unit 232 (e.g., a signal indicating a change in the inductance of the induction element 300) and update the display 233 accordingly. The user may continue inserting the microcatheter 311 until the display 233 indicates that the microcatheter 311 has been inserted to a depth of 10 cm (i.e., the same depth as the guide catheter 310). At this point, the user may zero out the displacement again and then further insert the microcatheter 311 to a desired depth relative to the insertion depth of the guide catheter 310. In this scenario, the detected displacement displayed by the control unit 234 represents the displacement of the microcatheter 311 relative to the guide catheter 310. 【0027】 Once the microcatheter 311 (or any other compatible catheter) is inserted to the desired depth (for example, when the microcatheter 311 is positioned at the site where the procedure is to be performed), the microcatheter 311 may be fixed in place, and the input element 236 may be activated to zero out the displacement value. This zeroed displacement value can indicate that the microcatheter 311 is in the desired position. Subsequently, if the control unit 234 detects any displacement of the microcatheter 311, the control unit 234 may update the displacement value and cause the display 233 to update to reflect the change in displacement, which can immediately indicate to the user that the microcatheter 311 has moved. In this way, the user can easily detect when the microcatheter 311 has moved from the desired position. 【0028】 In some embodiments, the control unit 234 may provide an operating mode that outputs an alarm when it detects displacement of the catheter or other device within the insertion sheath 210. For example, the displacement sensor 230 may include an input element 236 that allows the user to enter such a mode after the catheter has been inserted to a desired depth. In some embodiments, as part of entering this mode, the control unit 234 may also set the displacement value to zero. Once in this mode, if the control unit 234 detects any displacement, or any displacement exceeding a defined threshold, it may output an alarm that warns the clinician that the catheter may need to be repositioned. In some embodiments, the control unit 234 may be configured to enter this mode automatically, for example, after failing to detect further catheter displacement over a defined amount of time. 【0029】 The above embodiment employing a guide element 300 to sense catheter displacement may offer several advantages. For example, the guide element 300 does not need to be placed inside the lumen 211a and can therefore be isolated from any fluids that may be present in the lumen 211a (e.g., blood). For similar reasons, the guide element 300 may be capable of detecting the displacement of catheters having various gauges and may be capable of detecting the displacement of one catheter (or other device) passing through another catheter. 【0030】 Figures 4A and 4B are partial cross-sectional side views showing another example of how the displacement sensor 230 may be integrated into the introduction sheath 210. In contrast to the induction-based displacement sensor 230 in Figures 3A and 3B, Figures 4A and 4B represent embodiments in which the displacement sensor 230 is optical-based. For example, the sensor unit 232 may include one or more optical sensors 400, which may be integrated into the shaft 211, or otherwise, each optical sensor 400 may be arranged to enable detection of markings on a catheter or other device passing through the introduction sheath 210. In the example depicted, the sensor unit 232 includes a first set of two optical sensors 400 located on one side of the shaft 211, and a second set of two optical sensors 400 located on the opposite side of the shaft 211 and offset from the first set of two optical sensors 400. However, in other embodiments, any number and arrangement of optical sensors 400 can be employed. In some embodiments, by including multiple sets of optical sensors 400 offset from one another, the displacement sensor 230 can detect the position of the catheter with a high level of granularity. Figures 4A and 4B show that the optical-based displacement sensor 230 may include similar components as described above. Therefore, a repeated description of such components is not provided. 【0031】 Figure 4B provides an example of a method by which the catheter 410 may be configured to be compatible with the introduction sheath 210 when the catheter 410 has an optical-based displacement sensor 230. As shown in the figure, the catheter 410 may include markings 411 spaced along the length of the catheter 410. The markings 411 may represent any type of mark that can be detected by the optical sensor 400. For example only, the markings 411 may be formed by printing radial lines at fixed intervals around the outer surface of the catheter 410, such that the markings 411 may be configured to reflect light emitted by the optical sensor 400. In some embodiments, the control unit 234 may be pre-programmed with or receive user input identifying the spacing between the markings 411. 【0032】 The control unit 234 may be configured to receive signals from each optical sensor 400 that identify when an optical sensor detects a marking 411. Such signals may be output directly to the control unit 234 or processed by an intermediate circuit. In either case, the control unit 234 may be configured to process the signals in a manner similar to that described above to determine the direction in which the catheter 410 is moving. 【0033】 Figures 5A and 5B are partial cross-sectional side views showing another example of how the displacement sensor 230 may be integrated into the introduction sheath 210. In this example, the displacement sensor 230 is mechanically based. For example, Figure 5A shows that the sensor unit 232 may include one or more rollers 500 extending into the lumen 211a of the shaft 211. The rollers 500 may be configured to contact the outer surface of the catheter (or other device) and rotate (or roll) as the catheter moves within the lumen 211a. In some embodiments, two rollers 500 located on opposite sides of the shaft 211 may be employed. In some embodiments, the rollers 500 may be configured to move inward and outward to accommodate the catheter or other devices of different gauges. For example, the rollers 500 may be coupled to the sensor unit 232 such that the rollers 500 are biased toward the lumen 211a when the catheter is inserted between them, while allowing the rollers 500 to move outward (e.g., distally or proximal, axially, pivoting, etc.). The sensor unit 232 may include a circuit (e.g., one or more rotary encoders) that outputs a signal indicating the direction and extent of rotation of the roller 500. In any case, the control unit 234 may be configured to process the signal in a manner similar to that described above to determine the direction in which the catheter 410 is moving. In particular, in embodiments in which the introduction sheath 210 includes a mechanically based displacement sensor 230, substantially arbitrary catheter displacement can be detected. In some embodiments, the roller 500 may be textured to prevent slippage, such as when there is blood on the catheter. 【0034】 As these examples demonstrate, the displacement sensor 230 may employ various types of sensor units 232, including but not limited to inductance-based, optical-based, and mechanical-based sensor units 232. Regardless of the type of sensor unit 232, the displacement sensor 230 may be configured to detect and display displacement in real time as the catheter or other device moves within the lumen 211a of the shaft 211. Thus, by integrating the displacement sensor 230 into the introduction sheath 210, clinicians can monitor the position or depth of the catheter or other device as it is inserted or moved within the patient's vascular system. In some embodiments, this monitoring can be performed with high precision, reducing or eliminating the need to use fluoroscopy during the procedure. 【0035】 Figures 6A–6D provide examples of how the displacement sensor 230, which may be configured in any of the various ways described above, may be used when the catheter 600 is inserted into the patient's vascular system via the introduction sheath 210. In this example, it is assumed that there is a treatment site where the tip of the catheter 600 is to be positioned. 【0036】 In Figure 6A, the introduction sheath 210 is inserted into the patient's vascular system at the insertion site, but the catheter 600 has not yet been inserted into the introduction sheath 210. It is assumed that the displacement sensor 230 is currently reporting a displacement value of zero, represented as 0.0 on the display 233. For illustrative purposes only, a clinician may press the input element 236 (or utilize the touchscreen interface of the display 233) to provide input via the wireless (or wired) circuit 235, supplying power to the displacement sensor 230 and causing the control unit 234 to reset the displacement value to zero. However, it should be noted that it is not necessary to set the displacement value to zero or any specific value before inserting the catheter. In particular, in some embodiments, the clinician may insert the catheter to the insertion site and then zero out the displacement value so that the displacement value defines the depth relative to the insertion site. 【0037】 Turning to Figure 6B, it is assumed that the clinician has inserted the catheter 600 through the introduction sheath 210 into the patient's vascular system until its distal end is positioned at the treatment site. It is also assumed that the insertion depth relative to the displacement sensor 230 is 20 cm, as indicated by 20.0 displayed on the display 233. In some embodiments, the clinician may have known that the treatment site was at a depth of 20 cm (e.g., based on previous use of the displacement sensor 230). In such embodiments, the clinician can position the catheter 600 at this depth by inserting the catheter 600 while monitoring the display 233 and stopping the insertion of the catheter 600 when the display reads 20.0. In other embodiments, such as when the depth of the treatment site is unknown, any suitable technique (e.g., fluoroscopy) may be used to guide the insertion of the catheter 600 to the appropriate depth. In any case, as the catheter 600 passes the displacement sensor 230, the control unit 234 may use the signal received from the sensor unit 232 to track / calculate the depth to which the catheter 600 is currently inserted, using either of the above or other suitable techniques, update the displacement value accordingly, and reflect the current displacement value on the display 233. 【0038】 Turning to Figure 6C, it is assumed that with the catheter 600 positioned at the treatment site, the clinician provides an input to reset the displacement value to zero. For example, the clinician can fix the catheter 600 to the patient's skin to prevent it from moving, and then press the input element 236 to cause the control unit 234 to reset the displacement value to zero. Next, it is assumed that the catheter 600 moves 1 cm proximal, as shown in Figure 6D. For example, the patient could pull, bump, or otherwise interact with the catheter 600 to cause this movement. As the catheter 600 moves, the control unit 234 may receive a signal from the sensor unit 232 indicating this movement and update the displacement value accordingly, displaying the updated displacement value (e.g., -1.0 in this example). As a result, the clinician can immediately determine that the catheter 600 has moved by looking at the display 233. In some embodiments, the control unit 234 may also output an alarm when it detects this movement. After detecting this movement, the clinician can return the catheter 600 to the treatment site by inserting it until the display 233 reads 0.0 again. 【0039】 Examples from Figures 6A-6D show that the displacement sensor 230 allows clinicians to detect and record the depth of a treatment site (or other location) within a patient's vascular system, thereby enabling them to accurately return the catheter (or other device) to the same treatment site. For example, a clinician can determine that the treatment site is at a depth of 20 cm by performing the process shown in Figure 6B. If it is desired to reinsert the catheter 600 into the treatment site after its removal, the displacement sensor 230 can be used during insertion to know exactly when the catheter has reached a depth of 20 cm. A similar technique can be used to position the catheter at a specific depth relative to another location. For example, if the depth of the hepatic artery relative to the insertion site is known, and a clinician wishes to insert a microcatheter into the hepatic artery at a specified depth, the above technique can be used to locate the hepatic artery and track the further insertion of the microcatheter to the specified depth. 【0040】 The displacement sensor 230 can also be used to measure distance within a blood vessel. For example, once the catheter is positioned at a first location in the vascular system, the clinician can reset the displacement value and then advance the catheter to a second location. Upon reaching the second location, the displacement value displayed on the display 233 can define the distance between the first and second locations. 【0041】 All examples and conditional statements set forth herein are intended for educational purposes to help in understanding the concepts provided by the inventors to advance the invention and the art, and should be construed as not being limited to the examples and conditions specifically listed herein. While embodiments of the invention are described in detail, it should be understood that various changes, substitutions, and modifications can be made herein without departing from the spirit and scope of the invention.

Claims

[Claim 1] A hub that forms a proximal opening into the lumen, A shaft extending distally from the hub, wherein the lumen extends through the shaft to form a distal opening, A displacement sensor comprising a sensor unit arranged to detect the amount of displacement of the catheter within the lumen and to output a signal representing the detected amount of displacement, A control unit configured to receive the signal from the sensor unit and maintain the displacement value based on the signal, and the control unit configured to output the displacement value, The displacement sensor includes, Includes, The displacement sensor includes an induction element positioned adjacent to the lumen, and the induction sheath detects the change in inductance when a metal element embedded in the catheter passes through the induction element. [Claim 2] The introduction sheath according to claim 1, wherein the displacement sensor further includes a display, and outputting the displacement value includes displaying the displacement value on the display. [Claim 3] The introduction sheath according to claim 1, wherein the catheter includes a guide catheter and a microcatheter or guidewire. [Claim 4] The sensor unit includes an inductive element, and the signal representing the detected displacement represents a change in inductance, according to claim 1. [Claim 5] The introduction sheath according to claim 1, wherein the sensor unit includes one or more optical sensors, and the signal representing the detected displacement represents light received by the one or more optical sensors. [Claim 6] The introduction sheath according to claim 1, wherein the sensor unit includes one or more rollers, and the signal representing the detected displacement represents the rotation of the one or more rollers. [Claim 7] The introduction sheath according to claim 1, further comprising a display as an input element, wherein outputting the displacement value includes displaying the displacement value on the display. [Claim 8] The introduction sheath according to claim 1, wherein the control unit is further configured to output an alarm in response to a change in the displacement value. [Claim 9] The introduction sheath according to claim 1, wherein the displacement sensor further includes a wireless circuit, and outputting the displacement value includes transmitting the displacement value to an external device via the wireless circuit. [Claim 10] A hub that forms a proximal opening into the lumen, A shaft extending distally from the hub, wherein the lumen extends through the shaft to form a distal opening, A displacement sensor comprising a sensor unit arranged to detect the amount of displacement of the catheter within the lumen and to output a signal representing the detected amount of displacement, A control unit configured to receive the signal from the sensor unit and maintain the displacement value based on the signal, The control unit includes a display that shows the displacement value, The displacement sensor includes, Includes, The displacement sensor includes an induction element positioned adjacent to the lumen, and the induction sheath detects the change in inductance when a metal element embedded in the catheter passes through the induction element. [Claim 11] The introduction sheath according to claim 10, wherein the sensor unit includes an inductive element positioned adjacent to the lumen, and the signal representing the detected displacement represents a change in the inductance of the inductive element caused when the catheter is displaced within the lumen. [Claim 12] The introduction sheath according to claim 11, wherein when the catheter is moved into the lumen, the catheter is positioned inside another catheter. [Claim 13] The introduction sheath according to claim 10, wherein the sensor unit includes one or more optical sensors, and the signal representing the detected displacement represents light reflected from a marking on the catheter when the catheter is displaced within the lumen. [Claim 14] The introduction sheath according to claim 10, wherein the sensor unit includes one or more rollers, and the signal representing the detected displacement represents the rotation of the one or more rollers caused by the catheter when the catheter is displaced within the lumen. [Claim 15] The introduction sheath according to claim 10, wherein the display constitutes an input element. [Claim 16] A hub that forms a proximal opening into the lumen, A shaft extending distally from the hub, wherein the lumen extends through the shaft to form a distal opening, A displacement sensor integrated into the shaft and having a display, wherein the displacement sensor is configured to calculate a displacement value of the amount of displacement so that the catheter is displaced within the lumen, and to display the displacement value on the display, Includes, The displacement sensor includes an induction element positioned adjacent to the lumen, and the induction sheath detects the change in inductance when a metal element embedded in the catheter passes through the induction element. [Claim 17] The displacement sensor is As the catheter is displaced within the lumen, the change in inductance caused by the catheter, As the catheter is displaced within the lumen, the light reflected by the catheter Alternatively, as the catheter is displaced within the lumen, rotation caused by the catheter may occur. The introduction sheath according to claim 16, wherein the displacement value is calculated based on any of the following.