Guiding access to epicardial bags with transthoracic ultrasound

Abstract

The name of the invention of the present disclosure is "guided access to epicardial bags with transthoracic ultrasound". The present disclosure relates to a method comprising using an imaging system outside a body of a patient, the imaging system being equipped with a first position sensor. An image of an anatomical landmark of an organ of a patient is acquired while using a positioning system to track the position and orientation of an imaging system. An anatomical landmark is marked on the image. The position of the marker in a 3D coordinate system of the positioning system is calculated. The calculated location is stored in a memory.

Description

Technical Field

[0001] The present disclosure generally relates to guiding invasive medical probes, and more particularly to further using ultrasound reference images to guide magnetically position-tracked needles inserted through the chest wall. Background Art

[0002] Techniques for assisting in guiding invasive medical probes have been previously proposed in the patent literature. For example, U.S. Patent 7,918,793 describes how images of electroanatomical maps of body structures having cyclic motion are superimposed on 3D ultrasound images of the structures. The electroanatomical data and the anatomical image data are synchronized by gating both the electroanatomical data acquisition and the anatomical image at specific points in the motion cycle. The transmission of the image data includes identifying points in the motion cycle at which the 3D image is captured or to be displayed.

[0003] As another example, U.S. Patent 9,414,770 describes a method that includes positioning body electrodes in electrical contact with a patient's body and positioning a probe within the patient's body. The position of the probe is tracked during patient respiration, and an indication related to the impedance between the body electrodes during respiration is determined. The method further includes calculating a function that correlates the position of the probe with the indication and applying the function to identify the end-expiration point of respiration based on subsequent indications related to the impedance.

[0004] In conjunction with the accompanying drawings, the present disclosure will be more fully understood from the following detailed description of examples of the present disclosure, wherein: Brief Description of the Drawings

[0005] Figure 1 is a schematic illustration of a catheter-based electroanatomical (EA) mapping and ablation system according to an example of the present disclosure;

[0006] Figure 2 is a schematic illustration of a combined ultrasound magnetic tracking and electrical tracking system according to an example of the present disclosure, the combined ultrasound magnetic tracking and electrical tracking system being configured for motion compensation guidance of needles and catheters inserted through the chest wall;

[0007] Figure 3 is a flowchart schematically illustrating a method for guiding a needle inserted through the chest wall according to an example of the present disclosure; and

[0008] Figure 4 is a flowchart schematically illustrating a method for Figure 3 performing motion compensation guidance of a needle inserted through the chest wall in Detailed Description

[0009] Overview

[0010] Pericardial treatments (such as radiofrequency (RF) ablation and / or pulsed field ablation (PFA)) can be used to alleviate cardiac problems (such as certain types of ventricular arrhythmias (VA)). VA can be treated by catheter ablation, where the catheter is inserted through the chest wall via a needle. However, it is difficult to guide the physician to insert the needle through the chest cavity and through the pericardial sac at the apex, as the exact position of the apex is not fully known during the procedure (e.g., due to different patient postures). The apex position is also sensitive to the respiratory cycle. One possible way to address this problem is to use fluoroscopy, which involves applying a high dose of X-ray radiation.

[0011] The examples of the present disclosure described below provide a technique that indicates a direct line of sight to the apex to the physician during the trans-thoracic insertion position tracking of the needle and subsequently during the insertion of the catheter via the needle to treat the apical tissue. This can be done without fluoroscopy when inserting the catheter into the pericardial sac.

[0012] The technique includes using an imaging system equipped with a first position sensor (e.g., a magnetic tree axial sensor (TAS)) to acquire reference images of the chest cavity and the heart. The US transducer is outside the patient's body. US imaging is performed within the working volume of a positioning system (e.g., ) having a positioning pad placed under the patient. The user acquires US images of the anatomical landmarks of the patient's organs (e.g., the LV apex), while the positioning system tracks the position and orientation of the US transducer being held based on the signals received from the TAS. The position and orientation of the handheld US transducer are determined in the coordinate system of the positioning system.

[0013] In some examples, the imaging system is a hand-held US transducer. In other examples, the imaging system can be a single-plane or bi-plane fluoroscopic imaging system. Although there is an exposure associated with capturing the reference image using fluoroscopy, this exposure is expected to be significantly less than the exposure required to guide the catheter during the procedure.

[0014] Once the user has located the apex on the reference image, the user marks the apex position on the image, and the marked position is calculated in the 3D coordinate system of the positioning system, and the calculated position together with the orientation of the transducer when observing the apex is used to identify the three-dimensional position of the marked apex within the working volume of the positioning system. This is subsequently used to determine how to insert the needle through the chest wall region to reach the apex of the heart.

[0015] To this end, after the physician marks the apex in the US image, the processor calculates the position of the mark in the 3D coordinate system of the positioning system and stores this position in space. The processor uses the known position and orientation of the US handle and the known field of view of the US image relative to the US handle to calculate this position. The calculated (i.e., computed) position is stored in the memory.

[0016] During subsequent clinical procedures, a physician inserts a needle equipped with a second position sensor (e.g., a magnetic position sensor) through the chest wall into the patient's body. By using the same or a similar positioning system to track in real time the position of the needle inside the body relative to the stored and calculated apical position, the physician can navigate the needle to an anatomical landmark.

[0017] In one example, the processor of the positioning system provides a trajectory, e.g., a linear trajectory that aligns the needle orientation with the US-estimated orientation to the calculated position of the LV (left ventricle) apex. The disclosed techniques use a visual tool to provide further guidance to the needle, which shows the marked apical position and the current position of the needle in the 3D coordinate system of the positioning system.

[0018] The disclosed techniques make real-time US imaging during needle insertion unnecessary because the position has been marked. However, due to the sensitivity of the LV apical position to the respiratory cycle, insertion through the pericardial sac at the apex remains a challenge.

[0019] In some examples, the processor monitors the impedance between patches of an electrical position detection system to estimate the resulting apical movement. In one example, several patches are positioned on the chest and three patches are positioned on the patient's back. The change in impedance between the patches is related to the observed apical movement and can be used by the processor to perform motion correction on the marked position of the apex to guide the physician to the apex during its continuous cyclic movement.

[0020] System Description

[0021] Figure 1 is a schematic illustration of a catheter-based electroanatomical (EA) mapping and ablation system 10 according to an example of the present disclosure. Figure 1 Illustrated is a physician 24 inserting a position-tracking needle 66 through the chest wall into the thoracic cavity of a patient 23, and subsequently inserting a catheter 214 through the needle, as Figure 2 shown in more detail in.

[0022] As seen in inset 45, a magnet-based position sensor 114 is disposed on the distal end 128 of the needle 66. Using a positioning system employing the position sensor 114, the processor guides the needle 66 (or cannula 66) near the heart 12, as described below.

[0023] Using trans-thoracic needle 66 insertion, the catheter 214 can be inserted through the needle 66 into the patient's thoracic cavity to access the heart 12 to sense and ablate arrhythmogenic epicardial tissue at the LV apex 99, as Figure 2 further shown in.

[0024] System 10 may include a plurality of catheters, where, for clarity, catheter 14 is shown in illustration 45 as being inserted separately from needle 66 (but may also be inserted by physician 24 through needle 66). Catheter 214 and catheter 14 may be of the same type of catheter.

[0025] The plurality of catheters may include catheters dedicated to sensing intracardiac electrograms (IEGMs) and / or for both sensing and ablation, as well as imaging catheters. Illustrated herein is an example end catheter 14 configured to sense IEGM and perform electroablation (in illustration 45, physician 24 contacts end assembly 28 with the heart wall to sense and / or ablate a target site in heart 12 using end electrodes 26, the end assembly including position sensor 29 and being assembled on shaft 44 of catheter 14).

[0026] As described above, magnetically-based position sensors 114 and 29 are respectively assembled at the distal end 128 of needle 66 and the distal end 28 of catheter 14. Sensors 114 and 29 may operate with positioning pad 25, which includes a plurality of magnetic coils 32 configured to generate a magnetic field in a predefined workspace. Details of this example of a positioning system (i.e., magnetically-based position sensing (i.e., 3D magnetic positioning)) technique are described in U.S. Patents Nos. 5,539,199, 5,443,489, 5,558,091, 6,172,499, 6,239,724, 6,332,089, 6,484,118, 6,618,612, 6,690,963, 6,788,967, 6,892,091.

[0027] System 10 includes one or more electrode patches 38 positioned to contact the skin of patient 23 to establish a position reference for impedance-based tracking functionality of positioning pad 25 and electrodes 26. For impedance-based tracking, current is directed toward electrodes 26 and sensed at electrode skin patches 38 such that the position of each electrode can be triangulated via electrode patch 38. Details of impedance-based position tracking techniques are described in U.S. Patents Nos. 7,536,218, 7,756,576, 7,848,787, 7,869,865, and 8,456,182.

[0028] Signals from electrode patches 38 are used by an electrical positioning system employing processor 56 to provide respiratory motion compensation while guiding catheter 11 to LV apex 99, as Figure 2 further described in.

[0029] Recorder 11 displays the electrocardiogram 21 captured using the body surface ECG electrodes 18 and the intracardiac electrogram (IEGM) captured using the electrodes 26 of the catheter 14. Recorder 11 may include pacing capabilities for pacing the heart rhythm and / or may be electrically connected to an independent pacemaker.

[0030] System 10 may include an ablation energy generator 50 adapted to conduct ablation energy to one or more electrodes at the distal end of a catheter configured for ablation. The energy generated by ablation energy generator 50 may include, but is not limited to, radiofrequency (RF) energy or pulsed field ablation (PFA) energy (including unipolar or bipolar high voltage DC pulses that may be used to effect irreversible electroporation (IRE)), or a combination thereof.

[0031] The patient interface unit (PIU) 30 is an interface configured to establish electrical connectivity between the catheter, electrophysiology equipment, power supply, and a workstation 55 for controlling the operation of system 10. The electrophysiology equipment of system 10 may include, for example, multiple catheters, positioning pads 25, body surface ECG electrodes 18, electrode patches 38, ablation energy generator 50, and recorder 11. Optionally and preferably, PIU 30 additionally includes processing capabilities for performing real-time calculations of catheter position and for performing ECG calculations.

[0032] Workstation 55 includes a memory 57, a processor 56 unit with a memory or storage device loaded with appropriate operating software, and user interface capabilities. Workstation 55 may provide multiple functions, optionally including: (i) performing three-dimensional (3D) modeling of the endocardial anatomy and rendering a model or anatomical map 20 for display on a display device 27; (ii) on the display device 27, displaying the activation sequence (or other data) compiled from the recorded electrogram 21 as a representative visual marker or image superimposed on the rendered electroanatomical (EA) map 20; (iii) displaying the real-time position and orientation of multiple catheters within the heart chambers; and (iv) on the display device 27, displaying sites of interest (such as where ablation energy has been applied). An article of commerce embodying the elements of system 10 may be the CARTO TM 3 system, which is purchased from Biosense Webster, Inc., 31 Technology Drive, Suite 200, Irvine, CA 92618.

[0033] Motion Compensation Guidance System to LV Apex Target

[0034] Figure 2FIG. 0 is a schematic illustration of a combined ultrasound magnetic tracking and electrical tracking system according to an example of the present disclosure, the combined ultrasound magnetic tracking and electrical tracking system being configured for motion compensated guidance of a trans-thoracic inserted needle 66 and a catheter 214 via the needle 66. Although the current example shows the ultrasound acquisition and the rest of the system components together, generally, the US image can be acquired and labeled (e.g., tagged) separately (e.g., at an earlier time and at a different location) from the US image of the catheter guidance procedure. This is possible because needle guidance only relies on the US image of the position marker, and the position information of the US hand-held transducer is acquired during the US procedure rather than during real-time US acquisition.

[0035] Figure 2 An imaging system is shown, such as a hand-held US transducer 211 equipped with a magnetic position sensor 222 (e.g., TAS 222), which emits signals indicating the position and orientation acquired by a positioning system (the same magnetic position tracking system included in a system 10 such as Figure 1 that used in guiding the needle 66).

[0036] The US system generates a US image 234 of the heart, which includes the LV 256 and the LV apex 299. After the user marks the LV apex 299 on at least one US image, the position and orientation of the hand-held US transducer 211 are analyzed and recorded by the processor 56.

[0037] Alternatively, other imaging systems (such as a single-plane or bi-plane fluoroscopic imaging system) are used, and a position sensor is mounted on the imaging part of the system.

[0038] As described in the flowchart below Figure 3 The processor 56 uses the stored position information of the LV marker 299 to display (27) on the anatomical model 244 of the LV 276 the calculated LV markers 288 (respectively to 299). The processor 56 further displays the needle 66 on the anatomical model and adds a straight (i.e., linear) trajectory 255 to the calculated LV apex marker 288. Alternatively, the processor can display the linear trajectory 255 between the needle position and the marked anatomical position in the 3D coordinate system of the positioning system.

[0039] Once the needle 66 is advanced in place, the physician inserts a catheter 214 (e.g., a catheter similar to catheter 14) via the needle 66 to diagnose and / or treat the LV apex tissue.

[0040] Motion Compensation Method for Guiding Catheter to LV Apex Target

[0041] Figure 3FIG. 0 is a flow chart schematically illustrating a method for guiding a trans-thoracic inserted probe according to an example of the present disclosure. The method includes two phases: a US tracking phase 300 and a subsequent catheter tracking phase 320. These phases may be performed in this order at different times and different locations.

[0042] According to the presented example, the algorithm performs a process that begins in phase 300, where a US operator (such as physician 24) performs a non-invasive US scan of the heart 12 using a handheld US transducer 211 at US imaging step 302. The handheld US transducer 211 includes a TAS sensor and performs imaging within the working volume of your positioning system (e.g., ).

[0043] Meanwhile, at handheld US transducer tracking step 304, the processor records the position and orientation of the handheld US transducer 211. The position and orientation are determined in the coordinate system of the positioning system.

[0044] In tagging step 306, the physician marks (299) the LV apex on the US image 234 of the heart LV region 256.

[0045] In landmark position calculation step 308, after the physician marks the apex in the US image, the processor calculates the position of the mark in the 3D coordinate system of the positioning system. The processor uses the known position and orientation of the handle and the known field of view of the US image relative to the handle to calculate this position. For example, this relationship may be determined during a calibration process.

[0046] In data storage step 310, the user stores this position.

[0047] The process described in phase 320 begins at data upload step 317, where the user (such as physician 24) uploads the LV apex position calculated and stored during the above steps 308 - 310 to the system 10.

[0048] Next, at visual guidance tool operation step, the user or the processor turns on a visual guidance tool, such as a visual guidance tool that shows the 3D coordinate system of the positioning system.

[0049] Assuming the visual tool is turned on, at LV marker display step 321, the processor displays an LV marker (which identifies the clinical target of the catheter) on the tool. The LV apex position may be marked there (e.g., marked as a star), while also marking the current position of the distal end of the needle (e.g., marked as a cursor). Additionally, the visual tool may display a line extending between the current position of the needle and the star position to indicate the path to follow when inserting the needle. As the physician inserts the needle, the cursor advances based on its tracked position. The physician may command a change in the orientation of the view (e.g., rotate the 3D coordinate system).

[0050] At the needle insertion step 322, the physician 24 inserts a position tracking needle into the patient's body (e.g., the thoracic cavity). The needle includes a TAS sensor preferably at the distal end of the needle.

[0051] At the needle position tracking step 324, the processor records the position and orientation of the distal end 128 inside the patient's body.

[0052] At the needle visualization step 326, after the processor has identified the position of the needle, the processor marks it on the screen and extends a line between the position of the needle and the apex.

[0053] At the needle guidance step 328, using the position signal from the sensor 114 of the needle 66, the processor can guide the distal end 128, for example, by calculating and displaying the advancement of the distal end 128 relative to the LV apex marker (e.g., label 288) on the anatomical model superimposed on the anatomical model at the needle guidance step 328.

[0054] As follows Figure 4 As described, the real-time needle guidance includes adjusting the trajectory 255 to the LV to compensate for respiratory movement.

[0055] Once the needle 66 is in place, the physician can puncture the sac and then insert the catheter through the puncture.

[0056] Figure 3 The flowcharts shown are chosen solely for conceptual clarity. This example may also include additional steps of the algorithm, such as occasionally using X-ray imaging. This step and other possible steps are deliberately omitted from the disclosure herein to provide a more simplified flowchart.

[0057] Figure 4 Is schematically illustrated a flowchart of a method for motion compensation during the trans-thoracic insertion of a needle according to an example of the present disclosure for guiding Figure 3 The needle.

[0058] The process begins at the visualization step 402, where the processor displays the position of the apex and the position of the distal end of the needle inside the body on the display 27.

[0059] At the electrical detection step 404 of body movement, the processor receives electrical position signals from an electrical positioning system employing patches 38 as described in Figure 1 And Figure 2 These signals indicate the movement of the LV marker with body movement (e.g., with patient respiration).

[0060] At the apex position monitoring and adjustment 406, the processor calculates and displays the new position of the apex.

[0061] At adjustment step 408, the processor adjusts the extended virtual line 255 based on the current position of the needle and the newly (due to body movement) calculated marker position 288 of the apex of the heart.

[0062] Once the needle reaches the target position, the physician inserts a catheter through the needle to perform the intended procedure (e.g., ablation to eliminate LV arrhythmia).

[0063] Examples

[0064] Example 1

[0065] A method includes using an imaging system (211) external to the patient's body, the imaging system (211) being equipped with a first position sensor (222). Acquiring an image (234) of an anatomical landmark (99) of the patient's organ (12) while using a positioning system to track the position and orientation of the imaging system (211). Marking (299) the anatomical landmark (99) on the image (234). Calculating the position of the marker in the 3D coordinate system of the positioning system. Storing the calculated position (288) in a memory (57).

[0066] Example 2

[0067] The method according to embodiment 1, and including inserting a needle (66) equipped with a second position sensor (114) into the patient's body. Tracking the position of the needle (66) inside the body. Using the positioning system and the position to guide the user to navigate the needle to the anatomical landmark (99).

[0068] Example 3

[0069] The method according to any one of embodiments 1 and 2, wherein guiding the needle (66) to the anatomical landmark (99) includes: using a visual tool (244) marked with the position thereon.

[0070] Example 4

[0071] The method according to any one of embodiments 1 to 3, wherein the visual tool (244) shows the 3D coordinate system of the positioning system.

[0072] Example 5

[0073] The method according to any one of embodiments 1 to 4, wherein guiding further includes displaying a linear trajectory (255) between the position of the needle (66) and the calculated anatomical position (288) in the 3D coordinate system of the positioning system.

[0074] Example 6

[0075] The method according to any one of embodiments 1 to 5, and comprising using body movement tracking (238) to adjust the marker position (288) to compensate for body movement.

[0076] Example 7

[0077] The method according to any one of embodiments 1 to 6, wherein the first position sensor and the second position sensor (222, 114) are magnetic position sensors used by a magnetic positioning system.

[0078] Example 8

[0079] The method according to any one of embodiments 1 to 7, wherein the imaging system is a handheld ultrasound probe.

[0080] Example 9

[0081] The method according to any one of embodiments 1 to 7, wherein the imaging system is a single-plane or bi-plane fluoroscopic imaging system.

[0082] Example 10

[0083] A system (10) comprising an imaging system (211) and a processor (56). The imaging system (211) is external to the patient's body, the imaging system (211) is equipped with a first position sensor (222) and is configured to acquire an image (234) of an anatomical landmark (99) of an organ (12) of the patient, while the position and orientation of the imaging system (211) are tracked by a positioning system using the first position sensor (222). The processor (56) is configured to: (i) mark (299) the anatomical landmark (99) on the image (234); (ii) calculate the position (288) of the marker in the 3D coordinate system of the positioning system; and (iii) store the marked position in a memory (57).

[0084] Although the examples described herein are mainly directed to cardiac diagnostic applications, the methods and systems described herein can also be used in other medical applications.

[0085] It should be understood that the above examples are cited by way of illustration, and the present disclosure is not limited to the content specifically shown and described above. On the contrary, the scope of the present disclosure includes combinations and sub - combinations of the various features described above, as well as their variations and modifications, which should be contemplated by those skilled in the art upon reading the above description, and which are not disclosed in the prior art.

Claims

1. A system comprising: an imaging system external to the patient's body, the imaging system being equipped with a first position sensor and configured to acquire images of anatomical landmarks of an organ of the patient, while a position and orientation of the imaging system is tracked by a positioning system using the first position sensor; and A processor, the processor being configured to: marking the anatomical landmark on the image; Calculating the position of the marker in the 3D coordinate system of the positioning system; as well as The calculated position is stored in memory.

2. A system according to claim 1, and comprising: a needle configured for insertion into the body of the patient, the needle being equipped with a second position sensor; and A processor is configured to track the position of the needle within the body and use the positioning system and the position to guide a user to navigate the needle to the anatomical landmark.

3. The system according to claim 2, wherein: The processor is configured to guide the needle to the anatomical landmark by using a vision tool having the location marked thereon.

4. The system according to claim 3, wherein: The vision tool shows the 3D coordinate system of the positioning system.

5. The system according to claim 4, wherein: The processor is further configured to guide by displaying a linear trajectory between the needle position and the calculated anatomical position in the 3D coordinate system of the positioning system.

6. The system according to claim 1, wherein: The processor is configured to adjust the calculated position using body motion tracking to compensate for the body motion.

7. The system according to claim 1, wherein: The first position sensor and the second position sensor are magnetic position sensors used by a magnetic positioning system.

8. The system according to claim 1, wherein: The imaging system is a handheld ultrasound probe.

9. The system according to claim 1, wherein: The imaging system is a single-plane or bi-plane fluoroscopic imaging system.

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