Showing the ducts in the brain

Abstract

The present invention provides a medical tracking system, which includes: a catheter, which is inserted into a blood vessel of a body part of a living subject, and the catheter includes a flexible shaft with a deflectable distal end and a position tracking transducer in the distal end, the position tracking transducer being configured to output a signal indicating the position of the transducer; a tracking subsystem, which is used to track the position of the distal end over time in response to the signal; a display; and a processing circuit, which is used to add the tracked position of the distal end to a movement log and present to the display an image of at least a portion of the body part having a representation of the length of the catheter shaft in at least one blood vessel of the body part, wherein corresponding positions along the length of the shaft are located in the image in response to corresponding tracking positions in the tracking positions from the movement log.

Description

Technical Field

[0001] The present invention relates to medical devices and particularly, but not exclusively, to catheter-based cerebral vascular tracking systems. Background Art

[0002] Real-time brain imaging is often performed using fluoroscopic techniques. For example, in cerebral angiography, a catheter is inserted into an artery in the leg or arm through a small incision in the skin. Using x-ray guidance, the catheter is navigated to the area being examined. Once there, a contrast agent is injected through the catheter tube, and images are captured using ionizing radiation.

[0003] Hartlep's U.S. patent publication 2003 / 0078485 describes a device for electrophysiological localization of a target area in the brain, the device comprising a multi-channel microprobe comprising at its active end a plurality of closely packed microelectrodes arranged axially in a row, via which electrophysiological output is obtained at the target area and forwarded to an evaluation unit, wherein the microprobes are assigned to a tracking device which allows position detection of the microprobes by a neuronavigation system and directionally planning of the insertion of the probes.

[0004] U.S. Patent Publication 2008 / 0183074 to Carls et al. describes an integrated surgical navigation and nerve monitoring system. The integrated system provides real-time visualization of the instrument relative to the patient's anatomy. The integrated system also acquires nerve monitoring information and incorporates it into the visualization of the patient's anatomy. The integrated system is also capable of integrating neurodiagnostic information (such as nerve conduction information) with anatomical and instrument position information to assess changes in nerve integrity and develop treatment strategies.

[0005] U.S. Patent 6,535,756 issued to Simon et al. describes an apparatus and method for storing and measuring the trajectory of a surgical instrument within an image-guided surgical navigation system. An icon representing the real-time trajectory of the tracked instrument is superimposed on one or more pre-acquired images of the patient. At the surgeon's command, the navigation system can store multiple trajectories of the instrument and create a static icon representing each saved trajectory for display. The surgeon can also measure the planar angle between any two trajectories. The angle is calculated in the plane of the image, so the angle will be calculated separately for each image displayed. In addition, the surgeon can choose to calculate and display the three-dimensional distance between two points defined by any two trajectories. Summary of the invention

[0006] According to one embodiment of the present disclosure, a medical tracking system is provided, which includes: a catheter configured to be inserted into a blood vessel of a body part of a living subject and moved around in the blood vessel, and the catheter includes a flexible shaft having a deflectable distal end and a position tracking transducer in the distal end, the position tracking transducer being configured to output a signal indicating the position of the transducer in the body part; a tracking subsystem configured to track the position of the distal end of the catheter over time in response to the signal; a display; and a processing circuit configured to add the tracked position of the distal end to a movement log, and present to the display an image of at least a portion of the body part of the living subject having a representation of the length of the catheter shaft in at least one of the blood vessels in the body part, wherein corresponding positions along the length of the shaft are located in the image in response to corresponding tracking positions in the tracking positions from the movement log.

[0007] In addition, according to an embodiment of the present disclosure, the processing circuit is configured to present the length of the axis so that corresponding positions along the length of the axis are located in the image in response to corresponding tracking positions in a movement log and a time sequence of the tracking positions, wherein one of the positions of the length of the axis closest to the distal end of the catheter corresponds to the nearest one of the tracking positions in the movement log.

[0008] In addition, according to an embodiment of the present disclosure, in response to retracting the distal end of the catheter in at least one blood vessel relative to at least one tracking position included in the movement log, the processing circuit is configured to remove the at least one tracking position from the movement log, generate a corrected movement log, and present a representation of the length of the axis in the corrected movement log.

[0009] Additionally, according to an embodiment of the present disclosure, the processing circuit is configured to confirm that the catheter has been retracted in at least one blood vessel relative to at least one tracking location in response to at least the distal end retracing its path along a route defined by at least some of the tracking locations included in the movement log.

[0010] Furthermore, in accordance with an embodiment of the present disclosure, the processing circuit is configured to define a side of the route around at least a given radius of a line connecting at least some of the tracking locations.

[0011] Furthermore, according to an embodiment of the present disclosure, the processing circuit is configured to register scanned images of at least a portion of a body part depicting a blood vessel, calculate a position of a wall of at least one blood vessel based on data of the registered images, and define a side of a route as being bounded by a wall of at least one blood vessel.

[0012] Additionally, according to an embodiment of the present invention, the catheter has a diameter of 1 mm or less.

[0013] In addition, according to an embodiment of the present disclosure, the tracking subsystem includes a location pad having at least one magnetic field radiator, the at least one magnetic field radiator being configured to transmit an alternating magnetic field into an area where a body part is located, and the position tracking transducer includes a coil for detecting at least a portion of the transmitted alternating magnetic field.

[0014] According to another embodiment of the present disclosure, a medical tracking method is also provided, the method comprising tracking over time the position of a deflectable distal end of a flexible shaft of a catheter configured to be inserted into and move about in a blood vessel of a body part of a living subject in response to a signal output by a position tracking transducer, the signal indicating the position of the position tracking transducer in the body part; adding the tracked position of the distal end to a movement log; and presenting to a display an image of at least a portion of the body part of the living subject having a representation of the length of the catheter shaft in at least one blood vessel of the body part, wherein corresponding positions along the length of the shaft are located in the image in response to corresponding tracking positions in the tracking positions from the movement log.

[0015] In addition, according to an embodiment of the present disclosure, the presentation includes presenting the length of the axis so that corresponding positions along the length of the axis are located in the image in response to corresponding tracking positions in a movement log, a time sequence of the tracking positions, wherein one of the positions of the length of the axis closest to the distal end of the catheter corresponds to the nearest one of the tracking positions in the movement log.

[0016] In addition, according to an embodiment of the present disclosure, the method includes: in response to retracting the distal end of the catheter in at least one blood vessel relative to at least one tracking position included in the movement log, removing at least one tracking position from the movement log, and generating a corrected movement log, wherein the presentation includes presenting a representation of the length of the axis in the corrected movement log.

[0017] Additionally, according to an embodiment of the present disclosure, the method includes confirming that the catheter has been retracted in at least one blood vessel relative to at least one tracking location in response to at least the distal end retracing a route defined by at least some of the tracking locations included in the movement log.

[0018] Additionally, in accordance with an embodiment of the present disclosure, the method includes defining a side of the route around at least a given radius of a line connecting at least some of the tracking locations.

[0019] Furthermore, according to an embodiment of the present disclosure, the method includes registering scanned images of at least a portion of a body part depicting blood vessels, calculating the position of a wall of at least one blood vessel based on data of the registered images, and defining a side of the route as being bounded by the wall of at least one blood vessel.

[0020] Also in accordance with an embodiment of the present disclosure, the catheter has a diameter of 1 mm or less.

[0021] Additionally, according to an embodiment of the present disclosure, the method includes transmitting an alternating magnetic field into a region in which the body part is located, and detecting at least a portion of the transmitted alternating magnetic field by a coil position tracking transducer included in the catheter.

[0022] According to another embodiment of the present disclosure, a software product is also provided, which includes a non-transitory computer-readable medium having program instructions stored therein, which, when read by a central processing unit (CPU), causes the CPU to track over time the position of a deflectable distal end of a flexible shaft of a catheter configured to be inserted into and move about in a blood vessel of a body part of a living subject in response to a signal output by a position tracking transducer, the signal indicating the position of the position tracking transducer in the body part; add the tracked position of the distal end to a movement log; and present to a display an image of at least a portion of the body part of the living subject having a representation of the length of the catheter shaft in at least one blood vessel of the body part, wherein corresponding positions along the length of the shaft are located in the image in response to corresponding tracked positions in the tracked positions from the movement log. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0024] Figure 1A and Figure 1B is a schematic illustration of a catheter-based cerebral vascular tracking system according to an embodiment of the present invention;

[0025] Figure 2A and Figure 2B They are respectively Figure 1A and Figure 1B Side and end views of a cerebral catheter used with the system;

[0026] Figure 3 To show the parts of the brain and Figure 2A and Figure 2B An image view of the tracked position of the cerebral catheter;

[0027] Figure 4 To show Figure 2A and Figure 2B A view of the history of the image of the tracking position of the cerebral catheter;

[0028] Figure 5 To show that Figure 2A and Figure 2B A view of a brain catheter showing an image of a part of the brain;

[0029] Figure 6 To show Figure 2A and Figure 2B A view of a history of images of the tracked position of the cerebral catheter after partial retraction of the cerebral catheter;

[0030] Figure 7 To show the parts of the brain and the Figure 6 A graphical view showing the history of positioning of the cerebral catheter;

[0031] Figure 8 Figure 2 shows a section of the brain and partial retraction of the brain catheter based on Figure 6 A view of the image showing the positioning of the historically corrected cerebral catheter;

[0032] Figures 9 to 11 To illustrate the effect of a cerebral catheter being advanced and retracted in a blood vessel Figure 1A and Figure 1B tracking movement of the cerebral catheter, updating of the movement log, and presenting a view of a representation of the cerebral catheter when the system is in use; and

[0033] Fig.12 To include Figure 1A and Figure 1B Flow chart of exemplary steps in a method of operating a system. DETAILED DESCRIPTION

[0034] Overview

[0035] Blood vessels in the brain can be interconnected via multiple routes, so a catheter inserted into the brain can travel between two points using multiple different routes. Due in part to the complexity of the blood vessel routes and the narrow width of the blood vessels, navigating a catheter in the brain can be extremely challenging. It is very important for physicians to see where the entire catheter is in the brain, not just its distal tip, in order to enable the catheter to be navigated efficiently in the brain, as time is often of the essence in brain surgery, such as when diagnosing and treating stroke patients.

[0036] If the physician takes the wrong route for the catheter, the physician generally wants to take the fewest steps to find the correct route through the complex maze of cerebral blood vessels. Allowing the physician to see the entire catheter positioning in the brain will help the physician to efficiently find the best and quickest route to the desired location.

[0037] Although the catheter can be visualized during fluoroscopy, it is preferably not used due to radiation exposure.

[0038] One solution is to use multiple tracking sensors along the length of the catheter to determine the location of different points on the catheter. However, due to the size of blood vessels in the brain, the diameter of the catheter can be about 1 mm, limiting the number of wires that can be included in the catheter for operating multiple sensors.

[0039] A single tracking sensor mounted near the distal tip of the catheter is used to provide the position of the distal tip. However, the rest of the catheter cannot be derived from the current tracked position of the distal tip because the catheter may have traveled along multiple routes to reach the current position of the distal tip.

[0040] Embodiments of the present invention provide a system for finding the location of the length of the shaft of a catheter in the brain of a living subject based on a movement log (e.g., a history) of the tracked position of a point (e.g., the distal tip) of the catheter. The tracked position is typically derived from readings received from a single tracking transducer (e.g., a single-axis sensor) disposed in the distal end of the catheter.

[0041] Based on the pre-registered image, an image of at least a portion of the brain of the living subject is presented to a display having a representation of the length of an axis of the cerebral catheter in at least one blood vessel of the brain and corresponding positions along the length of the axis positioned in the image displayed in response to corresponding tracked positions from a movement log.

[0042] As the catheter is advanced in the blood vessel, the tracked positions are added to the movement log, and the representation of the length of the shaft of the cerebral catheter is updated to reflect the new tracked positions that have been added to the movement log.

[0043] In some embodiments, the movement log is adjusted when the catheter is partially retracted so that the tracked position corresponding to the retracted portion of the movement log is removed from the movement log. If the movement log is not adjusted based on partially retracting the catheter, then using the movement log to present a representation of the length of the shaft of the cerebral catheter will make it appear to the physician that the catheter is performing a U-turn in the blood vessel, when in fact the catheter is retracted.

[0044] When a catheter is partially retracted, while the tracked position calculated during the retraction may be close to the tracked position of the same route (e.g., the same blood vessel) in which the catheter was advanced, the tracked position during the retraction is likely not to be exactly the same as the tracked position during the advancement of the catheter. Therefore, in order to identify whether the catheter has been partially retracted or merely advanced along another route close to the current route, it is necessary to calculate or estimate the side of the current route (e.g., the vessel wall) that the catheter has traveled so far.

[0045] The side of the current route can be estimated around a circle of a given radius connecting the tracked positions in the movement log, thereby creating an elongated tube representing the route. However, since blood vessels can be of various widths, and in some cases narrow blood vessels can be very close to each other, the above estimation may not be accurate enough for some applications.

[0046] In some embodiments, the side of the route can be defined by the location of the wall of the blood vessel through which the catheter travels. In some embodiments, a scanned image of at least a portion of the brain depicting the blood vessels (e.g., angiogram CT) can be registered by the system, and the location of the wall of the blood vessel can be calculated based on the data of the registered images.

[0047] The embodiments described herein have been described in connection with the brain. However, the invention may be implemented to track a catheter in a blood vessel of any suitable body part.

[0048] System Description

[0049] Documents incorporated herein by reference are to be considered an integral part of this application, except that, to the extent any term is defined in these incorporated documents in a manner that contradicts a definition explicitly or implicitly made in this specification, only the definition in this specification shall prevail.

[0050] Figure 1A and Figure 1B is a schematic illustration of catheter-based cerebral vascular tracking systems 20a and 20b according to an embodiment of the present invention.

[0051] In some embodiments, prior to performing the catheterization procedure, a CT image of the patient 32 is acquired. The CT image is stored in a memory 42 for subsequent retrieval by the processing circuit 40. The processing circuit 40 uses the image to present, for example, a brain portion image 59 on a display 56. In another embodiment, during the disclosed catheterization procedure, the systems 20a and 20b register the position of the distal end of the cerebral catheter 28 within the patient's brain using a reference frame of the brain image of the patient 32. The position of the distal end of the cerebral catheter 28 can be tracked using a tracking subsystem 33 that tracks the position and orientation coordinates of a position tracking transducer mounted at the distal end. The position tracking transducer is configured to output a signal indicating the position of the transducer in a body part (e.g., the brain). The signal is processed by the tracking subsystem 33 to track the position of the distal end of the cerebral catheter 28 over time. In some embodiments, the tracking subsystem 33 may be a magnetic tracking subsystem described in more detail below, and the position tracking transducer includes at least one coil, referenced to a magnetic field. Figure 3This is described in more detail. In other embodiments, the tracking subsystem 33 can be an electrical-based tracking subsystem that uses a plurality of head surface electrodes (not shown) to track the position of the cerebral catheter 28 based on signals emitted by at least one electrode of the cerebral catheter 28 (included in the position tracking transducer). The tracking subsystem 33 can be implemented using any suitable position tracking subsystem, such as, but not limited to, an ultrasound-based tracking system, wherein the position tracking transducer includes at least one ultrasound transducer. Using the tracking subsystem 33, the physician 54 advances the distal end of the cerebral catheter 28 through the blood vessel, reference Figures 3 to 12 This is described in more detail.

[0052] exist Figure 1A In the system 20a shown in FIG. 1 , the location pad 24a is implemented as a collar around the neck of the patient 32. By placing the location pad 24a around the neck, the location pad 24a is configured to automatically compensate for the patient's head movement. The location pad 24a includes a magnetic field radiator 26a, which is fixed in an appropriate position relative to the head of the patient 32 and transmits a sinusoidal alternating magnetic field to the area 30 where the head of the patient 32 is located. The console 50 electrically drives the radiator 26a via a cable 25. In one embodiment, further compensation for head movement is provided by attaching a reference sensor 21 to the forehead of the patient. The console 50 is configured to receive a signal from the reference sensor 21 via a cable 27. A position tracking system including a neck collar location pad is described in U.S. patent application 16 / 248,393, entitled "Position Sensor on Brain Clot Sheath and LocationPad Collar", filed on January 15, 2019, which is assigned to the assignee of the present patent application and its disclosure is incorporated herein by reference.

[0053] The physician 54, operating system 20a, holds a cerebral catheter controller handle 29, which is connected to the proximal end of the cerebral catheter 28. The controller handle 29 allows the physician 54 to advance and navigate the cerebral catheter 28 in the brain, for example, through the entry point 22 at the femoral artery of the patient 32. As described above and below, the physician 54 navigates the distal end of the cerebral catheter 28 with the aid of a real-time image, which is presented based on position and orientation signals from a position tracking transducer installed at the distal end of the cerebral catheter 28. The console 50 receives the position signal via the cable 19, which connects the handle 29 to the cerebral catheter 28.

[0054] The elements of the system 20a including the radiator 26a are controlled by a processing circuit 40, which includes a processing unit in communication with one or more memories (e.g., a memory 42). The processing circuit 40 may be mounted in a console 50, which includes an operating control 58, which typically includes a keypad and / or a pointing device, such as a mouse or a trackball. The physician 54 interacts with the processing circuit 40 using the operating controls on the handle 29 when performing registration of the system 20a. During the registration process, an image 59 of the brain portion is presented on the display 56. After the above-described registration process, the physician 54 uses the operating controls to advance the distal end of the brain catheter 28 to one or more desired locations in the brain.

[0055] Processing circuit 40 uses software stored in memory 42 to operate system 20a. In implementation, some or all of the functions of processing circuit 40 may be combined in a single physical component, or alternatively, multiple physical components may be used to implement. These physical components may include hardwired or programmable devices, or a combination of the two. In some embodiments, at least some of the functions of processing circuit 40 may be implemented by a programmable processor under the control of suitable software. The software may be downloaded to the device in electronic form via a network, for example. Alternatively or in addition, the software may be stored in a tangible, non-transient computer-readable storage medium, such as an optical, magnetic or electronic memory.

[0056] In some embodiments, the console 50 may also include an irrigation pump 35 for Figure 2A and Figure 2B The cerebral catheter 28 described in more detail pumps the irrigation fluid. In some embodiments, the console 50 may include a Figure 2A and Figure 2B The signal generator 37 is described in more detail.

[0057] Figure 1B The system 20b shown in has a different magnetic position pad design, namely position pad 24b. As shown, position pad 24b is fixed to the bed and irradiator 26b is horizontally around the patient's headrest. In this example, system 20b lacks reference sensor 21, so the patient's head must be harnessed to prevent head movement. In some embodiments, reference sensor 21 may be included. The other components of system 20b are generally the same as those of system 20a. A position tracking system using a position pad similar to position pad 24b is described in U.S. patent application 15 / 674,380, entitled "ENT Image Registration," filed on August 10, 2017, which is assigned to the assignee of this patent application and its disclosure is incorporated herein by reference.

[0058] Figure 1A and Figure 1B The systems 20a and 20b shown in FIG. 2 are selected solely for conceptual clarity. Other system elements may be included, such as additional controls on the handle 29 for controlling additional tools such as for drug delivery.

[0059] Tracking the position and orientation of magnetic position sensors in organs of the body using techniques similar to those employed by systems 20a and 20b Magnetic tracking systems are produced by Biosense-Webster (Irvine, California). In general, position sensing using current distribution measurements and / or external magnetic fields is described in detail in U.S. Patents 5,391,199, 6,690,963, 6,484,118, 6,239,724, 6,618,612, 6,332,089, 7,756,576, 7,869,865, and 7,848,787, PCT Patent Publication WO 96 / 05768, and U.S. Patent Application Publications 2002 / 0065455A1, 2003 / 0120150A1, and 2004 / 0068178A1, the disclosures of which are incorporated herein by reference in their entirety.

[0060] See now Figure 2A and Figure 2B , which are respectively Figure 1A and Figure 1B Side and end views of a cerebral catheter 28 for use with systems 20a and 20b.

[0061] The cerebral catheter 28 is configured to be inserted into the blood vessels of the brain of a living subject and to move around in the blood vessels. The cerebral catheter 28 comprises a flexible shaft 61 with a distal end, which is generally deflectable (flexible), and its size is designed to fit in the blood vessels of the brain. The cerebral catheter 28 is generally formed as an elongated cylinder with a tapered distal end, which provides a smooth surface without any sharp angles or edges. In some embodiments, the cerebral catheter 28 has a diameter of 1mm or less. In some embodiments, the cerebral catheter 28 is compatible with magnetic resonance imaging (MRI). The outer shell of the cerebral catheter 28 can be made of polyamide or any suitable material.

[0062] The cerebral catheter 28 may include at least one bipolar electrode pair 60 . Figure 2AA cerebral catheter 28 with two bipolar electrode pairs 60 is shown. The cerebral catheter 28 may have any suitable number of bipolar electrode pairs 60. Each bipolar electrode pair 60 can detect signals indicating electrical activity in the brain without having to use body / head surface electrodes to detect electrical activity. In some embodiments, the body / head surface electrodes can be used as part of a tracking subsystem 33 to track the position of the bipolar electrode pairs 60 of the cerebral catheter 28. In some embodiments, the cerebral catheter 28 may include any suitable number of monopolar and / or bipolar electrodes for mapping and / or ablation purposes. In other embodiments, the cerebral catheter 28 may not include any electrodes. The bipolar electrode pairs 60 may be made of any suitable material, such as, but not limited to, platinum-iridium alloys. The electrodes may have any suitable width, such as 0.2mm to 0.6mm, and typically 0.4mm.

[0063] exist Figure 2A In the embodiment of the present invention, the position tracking transducer 62 is disposed between the two sets of bipolar electrode pairs 60. The position tracking transducer 62 can be disposed at any suitable position in the distal end, for example, near the distal end of the cerebral catheter 28. The position tracking transducer 62 is configured to output a signal indicating the position of the transducer 62 in the body part (e.g., the brain). The tracking subsystem 33 is configured to track the position of a point at the distal end of the cerebral catheter 28 in response to the signal output by the position tracking transducer 62. As described above with reference to Figure 1A and Figure 1B As described, tracking subsystem 33 includes location pad 24 having magnetic field radiator 26 configured to transmit an alternating magnetic field to brain region 30. In some embodiments, location tracking transducer 62 includes a coil to detect at least a portion of the transmitted alternating magnetic field. Figure 2A The coil is shown wound close to the surface of the cerebral catheter 28. In some embodiments, the coil is disposed beneath the outer housing of the cerebral catheter 28 and is generally disposed coaxially with the cerebral catheter 28. The coil may have any suitable diameter, such as between 0.5 mm and 1 mm, and in some embodiments, 0.65 mm.

[0064] The brain catheter 28 may include an optical fiber and a lens 64 disposed therein to capture images of the brain. In other embodiments, the optical fiber and the lens 64 are optional. The brain catheter 28 includes at least one irrigation channel 66 therein. The irrigation pump 35 ( Figure 1A to Figure 1B) is configured to pump irrigation fluid into the brain via irrigation channel 66 to provide cooling when ablation is used. The irrigation fluid can be any suitable fluid, such as but not limited to saline. The irrigation rate can be any suitable irrigation rate, such as but not limited to within the range of 5 to 25 ml / min, and is typically 15 ml / min. The irrigation fluid can also provide lubrication for moving the cerebral catheter 28 and preventing blood clots. In other embodiments, the irrigation channel 66 and the irrigation pump 35 are optional.

[0065] One or more of the bipolar electrodes 60 (or other electrodes) may be used to provide ablation functionality.Signal generator 37 may be configured to generate appropriate signals to be applied by electrodes 60 during ablation.

[0066] See now Figure 3 , which shows a portion of the brain 72 and Figure 2A and Figure 2B A view of image 70 of a tracked position 74 of the distal tip of cerebral catheter 28 . Figure 3 The distal tip of the cerebral catheter 28 is indicated to be located in one of a plurality of blood vessels 76 (some are labeled for simplicity only) of the brain 72. It is clearly seen that the remainder of the cerebral catheter 28 can be located along any of the various blood vessels 76 based solely on the tracking position 74.

[0067] See now Figure 4 , which shows Figure 2A and Figure 2B 7 is a view of the image 78 showing a history 80 of the tracked position of the cerebral catheter 28. The history 80 shows the position of the distal tip of the cerebral catheter 28 over time before the current tracked position 74.

[0068] See now Figure 5 , which shows a portion of the brain 72 and Figure 2A and Figure 2B FIG. 8 is a view of an image 82 of a representation 84 of a cerebral catheter 28. The positioning of the representation 84 of the cerebral catheter 28 corresponds to Figure 4 The history 80 of the cerebral catheter 28. The representation 84 provides an estimate of the current position of the cerebral catheter 28. Due to the lateral movement of the cerebral catheter 28 in the blood vessel 76 over time, the precise position of the cerebral catheter 28 may be slightly different from the position shown by the representation 84.

[0069] See now Figure 6 , which is shown in Figure 2A and Figure 2B FIG. 8 is a view of image 86 of updated history 80 of the tracked position of cerebral catheter 28 after cerebral catheter 28 has been partially retracted to a new tracked position 88 within blood vessel 76 . Figure 6 The distal tip of the cerebral catheter 28 is shown to have moved from the tracking position 74 ( Figure 5) retracts to a new tracking position 88.

[0070] See now Figure 7 , which is a view of image 90 showing portions of brain 72 and based on Figure 6 The positioning of the representation 92 of the cerebral catheter 28 is based on the updated history 80 of FIG. If the positioning of the representation 92 of the cerebral catheter 28 is based on the complete updated history 80 , the cerebral catheter 28 would appear to have performed a U-turn in one of the blood vessels 76 instead of retracting in one of the blood vessels 76 .

[0071] Reference now Figure 8 , which shows a portion of the brain 72 and a partial retraction of the brain catheter 28 based on Figure 6 A view of an image 94 of the location of a representation 96 of a cerebral catheter 28 corrected by the history 80. To correctly show the representation 96, when the most recently tracked position (e.g., the new tracked position 88) or position appears to have retraced its path on the path described by the history 80, the retraced portion of the path described by the history 80 is removed from the history. The representation 96 is then presented based on the corrected history without the retraced portion.

[0072] See now Figures 9 to 11 , which shows the tracking Figure 2A and Figure 2B FIG. 2 is a diagram of the movement of the cerebral catheter 28, wherein the cerebral catheter is advanced and retracted in the blood vessel 76 for use Figure 1A and Figure 1B When the systems 20a and 20b are used, the movement log 98 is updated and a representation 100 of the cerebral catheter 28 is presented.

[0073] Fig. 9 The distal end of the cerebral catheter 28 is shown to have been advanced in one of the blood vessels 76 and moved from position L1 to position L6 via positions L2, L3, L4 and L5 over time. The movement log 98 mirrors this movement and includes log entries for L1, L2, L3, L4, L5 and L6.

[0074] Fig. 9 Also shown is a route 102 (shown as having a lighter shade than the surrounding brain tissue) defined by the tracking locations in the movement log 98. The sides 102 of the route 102 may be defined by the walls of the blood vessel 76. Alternatively, it may be assumed that the sides of the route 102 are located at a fixed radius around a line 106 connecting the tracking locations (L1, L2, L3, L4, L5, and L6). By way of example, arrow 104 indicates the fixed radius at location L3.

[0075] Fig. 9Also shown is an image 108 that includes a portion of the brain 72, one of the blood vessels 76, and a representation 100 of the cerebral catheter 28 in the blood vessel 76. The positioning of the representation 100 of the cerebral catheter 28 corresponds to the tracked positions L1, L2, L3, L4, L5, and L6. The positioning of the representation 110 of the distal tip of the cerebral catheter 28 corresponds to the most recent tracked position L6.

[0076] Fig.10 It is shown that the distal end of the cerebral catheter 28 has been further advanced in one of the blood vessels 76 and moved from position L6 to position L7 along route 102. The movement log 98 mirrors this movement, and the tracking position L7 has been added to the movement log 98. Fig. 9 Also shown is a route 102 (shown in lighter shading) defined by the tracking locations in the movement log 98 that has been expanded to include the tracking location L7. The sides 102 of the route 102 may be defined by the walls of the blood vessel 76. Alternatively, the sides of the route 102 may be assumed to be located at a fixed radius around the line 106 connecting the tracking locations (L1, L2, L3, L4, L5, L6, and L7), as previously described with reference to FIG. Fig. 9 described.

[0077] Fig.10 Also shown is an image 108 that includes a portion of the brain 72, one of the blood vessels 76, and a representation 100 of the cerebral catheter 28 in the blood vessel 76. The positioning of the representation 100 of the cerebral catheter 28 now corresponds to the tracked positions L1, L2, L3, L4, L5, L6, and L7. The positioning of the representation 110 of the distal tip of the cerebral catheter 28 corresponds to the latest tracked position L7.

[0078] Now go to Fig.11 , Fig.11 The upper left quadrant of shows that a new tracking position L8 has been tracked and received for processing circuit 40 ( Figure 1A to Figure 1B ) is further processed. It can be seen that L8 has retraced its path on route 102, thus representing the retraction of cerebral catheter 28 in vessel 76. Although L8 is not exactly located on line 106, route 102 is defined by side 112, and thus the retracing of position L8 on route 102 also defines whether or not position L8 is within the boundaries of route 102.

[0079] Tracking locations included in movement log 98 that represent the segment of route 102 on which the distal end retraced its course, namely L7 in this example, are removed from movement log 98. To this end, Fig.11 The movement log 98 in FIG. 1 (lower left quadrant) shows that L7 has been removed from the movement log 98 and L8 has been added to the movement log. Therefore, the movement log 98 now includes L1 to L6 and L8.

[0080] Fig.11The upper right quadrant of shows an updated route 102 and an updated line 106 defined by the tracked locations of the updated movement log 98 .

[0081] Fig.11 The lower right quadrant of shows an image 108 that includes a portion of the brain 72, one of the blood vessels 76, and a representation 100 of the cerebral catheter 28 in the blood vessel 76, the representation being positioned according to the tracked retraction of the cerebral catheter 28. The positioning of the representation 100 of the cerebral catheter 28 now corresponds to the tracked positions L1, L2, L3, L4, L5, L6, and L8. The positioning of the representation 110 of the distal tip of the cerebral catheter 28 corresponds to the latest tracked position L8.

[0082] By further example, if the cerebral catheter 28 is further retracted to a tracking position L9 (not shown) that is behind both L6 and L8 in the path 102 , the tracking positions L6 and L8 are removed from the movement log 98 and the tracking position L9 is added to the movement log 98 .

[0083] Reference now Fig.12 , which is shown to include Figure 1A and Figure 1B Flowchart of exemplary steps in a method of operating systems 20a and 20b.

[0084] Processing circuit 40( Figure 1A to Figure 1B ) is configured to register (block 122) at least a portion of the brain 72 ( Figures 5 to 8 ) of a scanned image (e.g., a CT angiogram) depicting blood vessel 76 ( Figures 5 to 11 ). The processing circuit 40 may be configured to calculate (block 124) the position of the wall of the blood vessel 76 based on the data of the registered images.

[0085] Tracking subsystem 33 ( Figure 1A to Figure 1B ) is configured to track the cerebral catheter 28 ( Figure 1A to Figure 1B ). The tracking subsystem 33 may periodically sample the position.

[0086] The processing circuit 40 is configured to receive (block 128) a new tracked position of a point of the distal end of the cerebral catheter 28. It should be noted that not all received tracked positions are to be acted upon and used for further calculations and / or decisions. For example, if a newly received tracked position is spatially identical to a point stored in the movement log 98 ( Figures 9 to 11 ) is not far enough away, the newly received tracking position can be discarded.

[0087] In decision block 130, processing circuit 40 is configured to respond to at least one of the following conditions: Figures 9 to 11) to determine whether the cerebral catheter 28 has moved relative to the point already in the movement log 98 ( Figures 9 to 11 ) is retracted within the blood vessel 76, the point being defined by at least some of the tracking locations included in the movement log 98.

[0088] If processing circuit 40 determines (branch 132) that the distal end of cerebral catheter 28 is located relative to the point included in movement log 98 ( Figures 9 to 11 ) retracts in the blood vessel 76, the processing circuit is configured to remove (block 134) the one or more tracking locations from the movement log 98, generating a revised movement log 98. The process then continues with the step of block 136.

[0089] If the processing circuit 40 does not confirm (branch 138 ) that the point at the distal end of the cerebral catheter 28 is retracted, the step of box 134 is skipped and processing continues with the step of box 136 .

[0090] The processing circuit 40 is configured (block 136 ) to add the new tracked position of the point of the distal end to the movement log 98 .

[0091] The processing circuit 40 is configured to define (block 140) the route 102 from the tracked locations currently included in the movement log 98. The processing circuit 40 is also configured to define the side 112 ( Figures 9 to 11 ). The path 102 is defined as an elongated volume formed by the vessel wall or surrounding line 106 ( Figures 9 to 11 ), which joins the tracking positions in the movement log 98. At the point closest to the tracking position in the movement log 98, the end of the route corresponding to the distal tip of the cerebral catheter 28 can be defined by a plane perpendicular to the line 106, or perpendicular to the centerline defined by the wall of the blood vessel 76. In some embodiments, the processing circuit 40 is configured to define the side 112 of the route 102 based on at least the given radius around the line 106 connecting the tracking positions in the movement log 98. In other embodiments, the processing circuit 40 is configured to define the side 112 of the route 102 as being bounded by the wall of the blood vessel 76.

[0092] The processing circuit 40 is configured (block 142) to display 56 ( Figure 1A to Figure 1B ) presents with blood vessels 76 ( Figures 5 to 11 ) of at least a portion of the brain of a living subject, and an image 108 ( Figures 9 to 11), wherein the image 108 is positioned at a corresponding position along the length of the axis in response to a corresponding tracking position of a tracking position in a movement log 98, the movement log being modified to add one or more tracking positions and optionally modified to remove one or more tracked positions, as described in the step of box 134.

[0093] In some embodiments, the processing circuit 40 is configured to present a representation of the length of the axis such that corresponding positions along the length of the axis are positioned in the image 98 in response to corresponding tracking positions according to a chronological order of the tracking positions in the movement log 108, where the position of the length of the axis closest to the distal tip of the cerebral catheter 28 corresponds to the nearest one of the tracking positions in the movement log.

[0094] For the sake of clarity, various features of the present invention described in the context of separate embodiments may also be provided in combination in a single embodiment. Conversely, for the sake of simplicity, various features of the present invention are described in the context of a single embodiment and may also be provided separately or in any suitable sub-combination.

[0095] The above embodiments are cited by way of example, and the present invention is not limited by what is specifically shown and described above. On the contrary, the scope of the present invention includes combinations and sub-combinations of the various features described above, as well as variations and modifications thereof, which should occur to those skilled in the art when reading the above description, and which are not disclosed in the prior art.

Claims

1. A medical tracking system comprising: a catheter configured to be inserted into and moved about a blood vessel of a body part of a living subject, the catheter comprising a flexible shaft having a deflectable distal end and a position tracking transducer in the distal end, the position tracking transducer configured to output a signal indicative of a position of the transducer in the body part; a tracking subsystem configured to track a position of the distal end of the catheter over time in response to the signal; monitor; as well as A processing circuit, the processing circuit being configured to: adding the tracked position of the distal end to a movement log; and presenting to the display an image of at least a portion of the body part of the living subject having a representation of the length of the shaft of the catheter in at least one of the blood vessels of the body part, wherein respective positions along the length of the shaft are located in the image in response to respective ones of the tracked positions from the movement log, Wherein, in response to retracting the distal end of the catheter in the at least one blood vessel to a new tracking position relative to at least one of the tracking positions included in the movement log, the processing circuit is configured to remove from the movement log the at least one tracking position corresponding to the retracted portion depicted by the movement log and add the new tracking position of the distal end of the catheter to the movement log to generate a revised movement log and present the representation of the length of the axis of the catheter based on the revised movement log.

2. A system according to claim 1, wherein the processing circuit is configured to present the length of the axis so that the corresponding positions along the length of the axis are located in the image in response to the corresponding tracking positions based on the time sequence of the tracking positions in the movement log, wherein one of the positions of the length of the axis closest to the distal end of the catheter corresponds to the nearest one of the tracking positions in the movement log.

3. A system according to claim 1, wherein the processing circuit is configured to confirm that the catheter has been retracted in the at least one blood vessel relative to the at least one tracking location in response to at least the distal end retracing its path along a route defined by at least some of the tracking locations included in the movement log. 4 . The system of claim 3 , wherein the processing circuit is configured to define a side of the route based on at least a given radius around a line connecting the at least some of the tracked locations.

5. The system of claim 3, wherein the processing circuit is configured to: registering a scanned image of at least a portion of the body part depicting the blood vessel; calculating the position of the wall of the at least one blood vessel based on the data of the registered images; and A side of the route is defined as being bounded by a wall of the at least one blood vessel. The system of claim 1 , wherein the catheter has a diameter of 1 mm or less.

7. A system according to claim 1, wherein the tracking subsystem includes a location pad, the location pad having at least one magnetic field radiator, the at least one magnetic field radiator being configured to transmit an alternating magnetic field into an area where the body part is located, and the position tracking transducer includes a coil for detecting at least a portion of the transmitted alternating magnetic field.

8. A software product comprising a non-transitory computer-readable medium storing therein program instructions, which, when read by a central processing unit (CPU), cause the CPU to: tracking the position of a deflectable distal end of a flexible shaft of a catheter configured to be inserted into and moved about a blood vessel of a body part of a living subject over time in response to a signal output by a position tracking transducer, the signal being indicative of a position of the position tracking transducer in the body part; adding the tracked position of the distal end to a movement log; and presenting to a display an image of at least a portion of the body part of the living subject having a representation of the length of the shaft of the catheter in at least one blood vessel of the body part, wherein respective positions along the length of the shaft are located in the image in response to respective ones of the tracked positions from the movement log, Wherein, in response to retracting the distal end of the catheter in the at least one blood vessel to a new tracking position relative to at least one of the tracking positions included in the movement log, the CPU is configured to remove from the movement log the at least one tracking position corresponding to the retracted portion depicted by the movement log and add the new tracking position of the distal end of the catheter to the movement log to generate a revised movement log and present the representation of the length of the axis of the catheter based on the revised movement log.

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