Apparatus and method for intravascular navigation using beacon signals

Abstract

The present invention discloses an apparatus and method for navigating intravascular devices using uniquely identifiable navigation signals generated by artificial and / or natural beacons. The apparatus comprises signal generators that encode uniquely identifiable codes in generated beacon signals and transmit such signals via devices inserted into or otherwise connected to a patient's body. While navigating through the vasculature, an intravascular device receives, at its distal end, such beacon signals and transmits these signals to said apparatus connected outside the patient's body. The apparatus comprises signal processing units that decode the received signals, identify the source beacons based on their unique codes, and estimate the location of the distal end of the intravascular device relative to the location of the identified source beacons. The locations of the transmitting beacons and of the distal end of the intravascular device relative to these beacons are displayed in real time on a graphical interface.

Description

APPARATUS AND METHOD FOR INTRAVASCULAR NAVIGATIONUSING BEACON SIGNALSDescriptionREFERENCES CITED CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priorities to U.S. Provisional Patent Application Serial No. US 63 / 709,544 filed on October 21, 2024 entitled "Apparatus and method for intravascular navigation using beacon signals".U.S. PATENT DOCUMENTS

[0002] 5,099,845 3 / 1992 Besz et al. Medical instrument location means9,681,823 6 / 2017 Messerly et al. Integrated system for intravascular placement of a catheter10,321,890 6 / 2019 Grunwald et al. Apparatus and method for endovascular device guiding and positioning using physiological parameters 10,335,240 7 / 2019 Grunwald et al. Endovascular navigation system and method 11,000,207 5 / 2021 Burnside et al. Multiple coil system for tracking a medical device 11,122,990 9 / 2021 Grunwald et al. Apparatus and method for intravascular catheter navigation using the electrical conduction system of the heart and control electrodes11,172,843 11 / 2021 Kassab et al. Devices and systems for navigation and positioning a central venous catheter within a patient 2006 / 0173251 8 / 2006 Govari et al. Current-based position sensingFOREIGN PATENT DOCUMENTS EP0775466 5 / 1997 Wittkampf Catheter mapping system and method W02010 / 130723 11 / 2010 Konings et al. Central venous line insertion monitoring systemOTHER PUBLICATIONS

[0003] 1. Konings M.K. et al., Correct positioning of central venous catheters using a new electric method, Journal of Vascular Access JVA (2015) 16(4), 327-332TECHNICAL FIELD OF THE INVENTION

[0004] The present invention relates generally to devices and methods used for guiding and placement of intravascular devices in a patient's body. More specifically, the present invention relates to using extracorporeal signal sources or beacons to identify the location of an intravascular device. In particular, the present invention relates to using extracorporeal beacons that emit uniquely identifiable signals into a patient's body through skin electrodes. The uniquely identifiable beacon signals are received by an intravascular device as the device passes in the proximity of such beacons. The received signals are used to identify the emitting beacon and to determine and display the intravascular device location within the patient's vasculature relative to the emitting extracorporeal beacon location.BACKGROUND OF THE INVENTIONClinical Background

[0005] In endovascular procedures, the navigation of an intravascular device to the desired location of the endovascular procedure in a patient's vasculature is of major importance for the successful outcome of the procedure, for example in endovascular surgery, percutaneous creation of arterio-venous fistulas, percutaneous bypass creation, placement of central venous catheters, etc. Currently, in most situations, guiding and positioning intravascular devices is achieved using fluoroscopy in an operating room or in a radiology suite. For the placement of central venous catheters, ECG-based catheter guidance, magnetic guidance, and ultrasound imaging are also used.

[0006] However, fluoroscopy involves radiation and injection of contrast medium, ECGbased methods lack the ability to support intravascular device navigation outside the thoracic cavity, the use of magnetic guidance is limited to compatible intravascular devices and limited in the case of small body patients, e.g., children and neo-nates, and ultrasound imaging requires two operators to use and extensive training.Related Art

[0007] In U.S. Pat. No. 5,099,845, Besz et al. describe an instrument for determining the location of a device which has a radiating element forming part of the instrument to be inserted into the patient's body. The element inside the body radiates a signal and the signal is detected by at least one receiving element outside the body. The distance between the radiating and the receiving elements is calculated based on the level of energy detected between the transmitting and thereceiving elements. One limitation of the disclosed instrument is that the energy attenuation between the transmitting and the receiving elements depends on tissue characteristics and, thus, the location within the body cannot be accurately determined. Another limitation of the disclosed instrument is that the emitting element is inside the body, thus increasing the risk to the patient. Yet, another limitation of the disclosed system is that it requires an additional dedicated member to be incorporated into the catheter, thus limiting the types of catheters and other intravascular devices that can be used.

[0008] In U.S. Pat. No. 9,681,823, Messerly et al. describe an integrated catheter placement system for accurately placing a catheter within a patient's vasculature comprising a tip location magnetic sensor placed on the patient's chest, an ultrasound probe, and an ECG-based catheter tip guidance. One of the limitations of the disclosed system is that the magnetic tip location, as well as the ECG-based catheter guidance, are limited to the chest cavity. Another limitation is that the system can be used only for certain intravascular devices accommodating magnetic detection. Yet, another limitation of the disclosed system is that it requires an additional dedicated member to be incorporated into the catheter, thus limiting the types of catheters and other intravascular devices that can be used.

[0009] In U.S. Pat. No. 10,321,890, Grunwald et al. describe an endovascular navigation system and method based on sensing and processing electrogram signals of the venous vasculature of a patient. One limitation of the disclosed system and method is that they are based on sensing and processing electrocardiogram (ECG) signals only. As a result, the endovascular navigation using the disclosed system and method is limited to the venous vasculature where the ECG signals are indicative of specific locations within the vasculature, i.e., is limited to the venous vasculature in and in the proximity of the patient's heart.

[0010] In U.S. Pat. No. 10,335,240, Grunwald et al. describe an endovascular navigation system including a flexible member for accessing the venous vasculature of a patient having a sensor disposed at the distal end that is configured to sense physiological characteristics of the venous vasculature. One limitation of the disclosed system is that it can only be used in the venous vasculature. Another limitation is that the system can be used only for certain intravascular devices accommodating the sensor disposed at the distal end. Yet, another limitation of the disclosed system is that it requires an additional dedicated member to be incorporated into the catheter, thus limiting the types of catheters and other intravascular devices that can be used.

[0011] In U.S. Pat. No. 11,000,207, Burnside et al. describe a system for tracking one or more medical devices for insertion into the body of a patient. The system employs multiple radiating elements that can be simultaneously detected by a sensor unit, wherein at least one of the radiating elements is included with the medical device. Another of the radiating elements may beplaced at a predetermined point on the skin of the patient to serve as a landmark to help determine the location of the medical device with respect to the landmark. One limitation of the disclosed apparatus is that, being based on radiating elements, it relies on artificial landmarks and cannot use location determination based on physiological landmarks, i.e., based on signals naturally emitted by the body. Another limitation of the disclosed system is that it requires a radiating element to be included with the medical device, thus limiting its applicability to only the medical devices that can accommodate such a radiating element. Further, radiating elements are subject to electromagnetic interference which limits their utilization certain medical environments, such as the operating rooms.

[0012] In U.S. Pat. No. 11,122,990, Grunwald et al. describe an apparatus, algorithm, and method for intravascular navigation and placement using the electrical conduction system of the heart and control electrodes placed on patient's skin. A limitation of the disclosed apparatus is that navigation and placement are limited to the vasculature where the electrical conduction system of the heart and the control electrodes provide location differentiation.

[0013] In U.S. Pat. No. 11,172,843, Kassab et al. describe devices and systems for navigation and positioning a central venous catheter within a patient. In one embodiment, the system is configured to measure the conductance between an excitation and a detection electrode located on the device to be inserted in the body, whereby the conductance measurements are indicative of the location of the electrodes within the body. One limitation of the disclosed system is that the energy emitting element is inside the patient body, thus increasing the risk to the patient. Another limitation of the disclosed system is that conductance measurements between the transmitting and the receiving elements are not accurately and repetitively indicative of the location of the system within the patient's vasculature. Yet, another limitation of the disclosed system is that it requires an additional dedicated member to be incorporated into the catheter, thus limiting the types of catheters and other intravascular devices that can be used.

[0014] In U.S. Patent Application 2006 / 0173251, Govari et al. describe a method for determining a location inside the body by inserting a probe comprising at least one electrode and passing electrical currents through the body between the internal electrode and a plurality of locations on the surface of the body. Respective characteristics of the currents passing through the plurality of locations are measured to determine position coordinates of the probe. One limitation of the disclosed method is that the energy generating element is on the probe inserted in the body which increases the risk to the patient. Another limitation of the method is the current characteristics depend not only on probe position but also on tissue characteristics, thus affecting the accuracy of location determination. Yet, another limitation of the disclosed system is that it requires an additional dedicated memberto be incorporated into the catheter, thus limiting the types of catheters and other intravascular devices that can be used.

[0015] In European Pat. No. EP775466, Wittkampf describes a system for catheter location mapping using triangulation and three substantially orthogonal alternating signals applied through a patient, directed toward the area of interest to be mapped. A catheter is equipped with a measuring electrode and a voltage is sensed between the catheter tip and a reference surface electrode, whereby the voltage signal has components corresponding to the three orthogonal applied current signals. A calibration procedure is used to provide the correlation between the three signals and dimensional locations. One limitation of the disclosed system is that the energy applied through three skin electrodes must be high enough to penetrate through the body into the heart, which represent a higher risk to the patient. Another limitation of the disclosed system is that the distance to the catheter is triangulated based on energy attenuation from the emitting electrodes, such estimation lacking accuracy because the energy attenuation depends also on tissue characteristics not only on distance. Yet another limitation of the disclosed system is that the calibration for providing location information is patient dependent. Yet, another limitation of the disclosed system is that it requires an additional dedicated member to be incorporated into the catheter, thus limiting the types of catheters and other intravascular devices that can be used.

[0016] In Patent Application WO 2010 / 13072 and publication [1], Konings et al. describe a catheter insertion monitor comprising a signal generator for generating a signal fed into the patient's body via a catheter. The monitor measures the electrical signal generated by the catheter using sensor electrodes attached to the body. The monitor further calculates the strength of the measured signal, whereby the signal has a maximum when the catheter is close to the cavoatrial junction. One limitation of the disclosed monitor is that it does not allow for navigation of the catheter but only indicates when the catheter may be close to the cavoatrial junctions. Another limitation is that the location at the cavoatrial junction is measured using sensor at the skin level, and thus, cannot accurately determine the exact location of the catheter within the body. A further limitation is related to risk to the patient represented by the amount of energy required to be generated by the catheter inside the patient and close to the heart. Yet, another limitation of the disclosed system is that it requires an additional dedicated member to be incorporated into the catheter, thus limiting the types of catheters and other intravascular devices that can be used.Clinical Need

[0017] What is needed are easy to use intravascular navigation devices and methods, with single-operator use in venous and arterial vasculature, non-invasive, radiation-free, that can beused for different types of intravascular devices, at the patient's bedside, and for all patient populations including adults, children and neo-nates.Contributions of the Present Invention

[0018] The present invention introduces an apparatus and method for navigation of intravascular devices in the vasculature of a patient using guiding signals generated by artificial and / or natural beacons.

[0019] The present invention discloses devices and methods for generating uniquely identifiable beacon signals that are delivered into the body by skin electrodes placed at known locations. One device and method for generating uniquely identifiable beacon signals disclosed herein use binary ID codes and Frequency Shift Keying modulation. Another device and method disclosed herein generate uniquely identifiable beacon signals by creating unique power spectrum characteristics, or power spectrum identities, for each individual beacon.

[0020] As disclosed herein, the beacon signal power spectra and signal energy comply with all applicable patient safety standards and guidelines. The beacon signal energy is delivered into the body to relatively shallow depths and sequentially, one beacon after another rather than simultaneously, in order to minimize the amount of energy delivered into the patient's body at any one time.

[0021] The present invention discloses devices, algorithms, and methods that allow to extract individual beacon signals / patterns from the superimposed beacon signals / patterns received by the apparatus through the intravascular device. A device and method disclosed herein consist of selectively filtering the beacon signals based on their individual spectral power characteristics as defined by the emitting artificial or natural beacon. In one embodiment of the present invention, a device and method are disclosed herein consisting in selectively filtering only P-wave components of the ECG signal 155 to simplify the identification of beacon signal 157.

[0022] Another device and method disclosed herein use an adaptive filter that adapts itself to signal changes, for example that adapts itself to changes in the P-wave as the catheter advances through the superior vena cava towards the sinoatrial node and the cavoatrial junction. Another device and method disclosed herein are the controlled distortion of natural beacon signals to simplify their differentiation from one another. For example, in one embodiment disclosed herein, the beacon signal is overamplified and binary coded and decoded.

[0023] The present invention discloses a new graphical user interface dedicated to beaconbased device navigation. It discloses a device and method to associate a certain beacon signal to a certain graphical user interface icon that estimates the device location relative to the emitting beacon. One element of the interface disclosed herein is the display of exemplary / templatesignals that allow the user to rapidly compare real-time beacon signals with the target template signal and to confirm or to infirm the presence of the device at the target location.

[0024] The present invention further discloses devices and methods for navigation using different energy sources, for example using visible and / or near-infrared light, to generate beacon signals and receive information about the location of the distal end of the intravascular device.

[0025] According to the present invention, any combination of natural and artificial beacons can be used for device navigation, thus making the device navigation flexible to apply and easy to use in clinical situations.

[0026] In one embodiment of the present invention, the beacon signal and the signal receiver are paired in such a way as to allow signal transmission and reception of the beacon signal through the lumen of the intravascular device filled with conductive saline solution. Thus, the navigation method according to the present invention can be used to navigate and guide any intravascular device currently in clinical practice for all patient populations and in all clinical settings.SUMMARY OF THE INVENTION

[0027] The present invention introduces an apparatus and method for navigation of intravascular devices in the vasculature of a patient using guiding signals generated by artificial and / or natural beacons.

[0028] In one exemplary embodiment of the present invention, the apparatus incorporates signal emitters or beacons that transmit uniquely identifiable signals into the patient's body via skin electrodes placed on the patient's skin at known locations.

[0029] In one exemplary embodiment of the present invention, the skin electrodes are placed at such locations as to enable the navigation of an intravascular device towards a desired destination within the body.

[0030] In one exemplary embodiment of the present invention, the skin electrodes are placed at such locations as to prevent the navigation of an intravascular device in an undesired direction within the body.

[0031] In one exemplary embodiment of the present invention, the apparatus receives signals emitted by natural beacons within the body, e.g., heart, brain, muscles.In one embodiment of the present invention, while navigating through the vasculature, an intravascular device receives at its distal end signals emitted by different beacons and transmits these signals to signal receivers of the apparatus connected to the proximal end of the device outside the patient's body.

[0032] In one exemplary embodiment of the present invention, the apparatus decodes received signals, identifies the source beacons, and displays the location of the intravascular device distal end within the vasculature relative to the location of the identified source beacons.

[0033] In one exemplary embodiment of the present invention, a new easy-to-use graphical user interface dedicated to beacon-based device navigation is disclosed.BRIEF DESCRIPTION OF THE DRAWINGS

[0034] FIG. 1 illustrates an embodiment of the navigation apparatus according to the present invention. FIG. 2 illustrates an embodiment of a block diagram of the data acquisition sub-system of the apparatus according to the present invention.FIG. 3 illustrates an embodiment of a block diagram of the user interface sub-system of the apparatus according to the present invention.FIG. 4 illustrates an embodiment of a simplified graphical user interface according to the present invention.FIG. 5 illustrates an embodiment of a graphical user interface displaying beacon identification signals according to the present invention.FIG. 6A illustrates an embodiment of a method of encoding beacon signals.FIG. 6B illustrates another embodiment of a method of encoding beacon signals.FIG. 7 illustrates an embodiment of a device used to encode beacon signals.FIG. 8 illustrates an embodiment of a block diagram of a device and method of extracting beacon signals.FIG. 9 illustrates an embodiment of a block diagram of a device and method of decoding beacon signals.FIG. 10 illustrates another embodiment of a block diagram of a device and method of extracting beacon signals.FIG. 11 illustrates an embodiment of a device and method of binary encoding of a natural beacon signal.FIG. 12 illustrates several natural beacons present in the human body.FIG. 13 illustrates amplitude vs. frequency characteristics of natural beacon signals and an embodiment of these characteristics for the artificial beacon signals according to the present invention.FIG. 14 illustrates an embodiment of intravascular navigation using natural beacons according to the present invention.FIG. 15 illustrates an embodiment of a device and method of separating and identifying different natural beacon signals.FIG. 16 illustrates an embodiment of the graphical user interface for navigation using natural beacons.FIG. 17 illustrates an embodiment of an apparatus using several artificial beacons of different energy types according to the present invention.FIG. 18 illustrates another embodiment of the graphical user interface of the apparatus according to the present invention.FIG. 19 illustrates an embodiment of an algorithm to process, analyze, identify, classify, and display beacon signals and device location.DETAILED DESCRIPTION OF THE INVENTION

[0035] FIG. 1 illustrates an embodiment of the navigation apparatus 100 according to the present invention. The apparatus includes one or more beacon signal generators 110, one or more beacon signal receivers 180, and one or more graphical user interface, processing, and control modules 190 as further described herein.

[0036] An intravascular device 160, e.g., a catheter, receives at its distal tip 165 the beacon signals 170 emitted by the beacon signal generators. The device 160 is connected at its proximal end to the signal receivers 180 by connective element 175.

[0037] A beacon signal, e.g., 125, is transmitted from the distal end 165 to the proximal end 175 of device 160 for example thorough conductive saline solution that fills the inner lumen of device 160. The beacon signal can also be transmitted by a guidewire used to place device 160, for example in a standard over-the-wire procedure or by a stylet used to place device 165, for example in a standard PICC (peripherally inserted central catheter) insertion procedure. In one embodiment of the present invention, no additional sensor or other dedicated device are needed to be connected to or otherwise incorporated into device 160. Thus, device 160 can be any intravascular device currently in use in clinical practice.

[0038] In one embodiment of the present invention, one or more beacon electrodes can be placed anywhere on the skin of patient 105. In one embodiment of the present invention, beacon electrode 120 is placed on the patient’s neck and beacon electrode 140 on the patient’s chest. Beacon 120 is connected to signal generator 110 by connective element 115 and beacon 140 by connective element 130. In one embodiment of the present invention, connective elements 115 and 130 are shielded electrically conductive wires.

[0039] In one embodiment of the present invention, beacons 120 and 140 contain data acquisition and transmission components and are wirelessly connected to signal generator 110

[0040] In one embodiment of the present invention, generator 110 generates AC signal 125 to be transmitted into the patient’s body by beacon 120 and alternating current signal 135 to be transmitted into the patient’s body by beacon 140.

[0041] In one embodiment of the present invention, the signal amplitudes and frequencies of the beacon generated signals 125 and 135 are selected in such a way as not to interfere with any physiological signals or with pacemaker signals. These amplitudes and frequencies allow for the required tissue penetration and are not influenced or minimally influenced by electromagnetic radiation generally present in the operating room or at the patient’s bedside. Furthermore, the amplitudes and frequencies of the alternating current delivered into the patient’s body comply with all applicable safety standards and FDA guidelines. In one embodiment of the present invention, alternating beacon current intensity is about 2mA (rms) with a frequency of about 60 kHz.

[0042] In one embodiment of the present invention, signals 125 and 135 are uniquely identifiable by their frequencies, as further described herein.

[0043] In one embodiment of the present invention, signals 125 and 135 are uniquely identifiable by frequency modulation and encoding, for example using Frequency Shift Keying (SFK), as further described herein.

[0044] In one embodiment of the present invention, signals 125 and 135 are frequency modulated by a unique binary code assigned to each beacon as further illustrated herein on FIG. 6A and FIG. 7.

[0045] Thus, each beacon signal can be individually decoded, identified and associated to the corresponding emitting beacon and its location when the beacon signal is received by signal receiver 180 through the intravascular device 160.

[0046] The human body contains natural beacons, i.e., generators of distinctive electrical signals, e.g., the heart (ECG signals), the brain (EEG signals), the muscles other than heart (EMG signals). Similarly to a beacon, the sinoatrial node (SAN) of the heart 150 generates an electrical signal with a unique signature 157. The unique signature of the sinoatrial natural beacon signal consists in an elevated P-wave, as extensively described in the literature. In another example, the ventricular heart muscles generate other electrical signals with unique signatures: the R-wave and the T-wave or the “RST” complex of an ECG signal 155.

[0047] In one embodiment of the present invention, by receiving and identifying signal 157, the apparatus according to the present invention can detect when the distal end 165 of intravascular device 160 approaches the sinoatrial node.

[0048] In one embodiment of the present invention, the artificial beacon signals 125 and 135 are superimposed onto natural beacon signal 157. As further described herein, receiver 180 separates each of the artificial beacon signals 125 and 135 and natural beacon signal 157 for further processing and interpretation.

[0049] In one embodiment of the present invention, receiver 180 is connected wirelessly to user interface sub-system 190.

[0050] As further described herein, in one embodiment of the present invention, user interface sub-system 190 contains one or several control units, information processing units, power management units, and graphical user interface units.

[0051] FIG. 2 illustrates an embodiment of a block diagram of a data acquisition subsystem 200 of apparatus 100 according to the present invention. In one embodiment of the present invention, data acquisition sub-system 200 contains signal generators and receivers, system control modules, data and information processing modules, and modules for wireless communication and power management.

[0052] In one embodiment of the present invention, the beacon signals generators 110 and receivers 180 can be integrated in one housing. In another embodiment of the present invention, each of the beacon signal generators and each of the beacon signal receivers can have their own housing.

[0053] In one embodiment of the present invention, connective elements 210 connect one or several signal generators 220 to one or several beacon electrodes placed on patient 105.In one embodiment of the present invention, intravascular device 160 is connected to one or several beacon signal receivers 230 by connective element 175. Beacon signal generators 220 and beacon signal receivers 230 are further described herein.

[0054] In one embodiment of the present invention, data processing module 240 contains resources for signal pre-processing, amplification, analog-to-digital conversion, and selective filtering as further described herein.

[0055] In one embodiment of the present invention, control module 250 contains system controls and microprocessors for system control firmware, as further described herein.

[0056] In one embodiment of the present invention, information processing module 260 contains digital signal processors (DSP) with their corresponding software and algorithmsfor time and frequency domain analysis, e.g., DFT and FFT, selective filtering, signal demodulation, binary decoding, binary sequence detection, pattern recognition for beacon signal identification, etc., as further described herein.

[0057] In one embodiment of the present invention, module 280 contains battery and power management components. In one embodiment of the present invention, one or several signal generators 220 can be turned off to minimize the amount of energy delivered into the patient’s body, as further described herein.

[0058] In one embodiment of the present invention, module 290 contains wireless communication components, e.g., Bluetooth or Wi-Fi (LAN) communication with user interface sub-system 300.

[0059] FIG. 3 illustrates an embodiment of a block diagram of the user interface subsystem 300 of apparatus 100 according to the present invention.

[0060] In one embodiment of the present invention, signals from data acquisition subsystem 200 are received by the wireless communication module 310 via Bluetooth or WiFi.

[0061] In one embodiment of the present invention, module 310 contains components for connecting user interface sub-system 300 to other devices, e.g., to a printer or to a wireless hospital network.

[0062] The user interface control module 320 translates user inputs into system commands and system information into display signals.

[0063] In one embodiment of the present invention, user interface sub-system 300 includes a graphical user interface 330 for displaying the location of the intravascular device and for interaction with the user, as further described herein.

[0064] In one embodiment of the present invention, graphical user interface 330 includes a touch screen for direct input of user commands.

[0065] In one embodiment of the present invention, information processing module 340 includes additional components for signal processing and algorithm implementation, as further described herein.

[0066] In one embodiment of the present invention, binary sequence detector 360 detects and identifies binary codes of corresponding beacon signals.

[0067] In one embodiment of the present invention, module 350 includes components for battery and power management.

[0068] In one embodiment of the present invention, module 370 includes components for system control.

[0069] In one embodiment of the present invention, the functionality of user interface sub-system 300 can be implemented as a stand-alone software module running on different operating systems on off-the-shelf standard tablets, mobile phones, or PCs having minimum performance characteristics dictated by the requirements disclosed herein.

[0070] FIG. 4 illustrates an embodiment 400 of a simplified graphical user interface according to the present invention. Icon 410 represents the pre-selected location of beacon electrode 120 and the region around this beacon electrode in which an intravascular device may receive signal 125 generated by this beacon. Icon 420 represents the preselected location of beacon electrode 140 and the region around this beacon electrode in which an intravascular device may receive the signal 135 generated by this beacon. Icon 430 represents the region around the sinoatrial node 150 in which an intravascular device may receive signal 157 generated by this natural beacon.

[0071] In one embodiment of the present invention, these three icons are initially grayed out indicating an inactive status.

[0072] In one embodiment of the present invention, the desired trajectory of the intravascular device, e.g., of a central venous catheter, is represented by the dotted line 450 when the device is advanced from the insertion point towards the heart. Typically, a central venous catheter would follow trajectory 450. In this situation, the catheter reaches the proximity of the sinoatrial node 150 represented by icon 430 on FIG. 4, beacon signal 157 is detected at the tip of the catheter, and icon 430 turns green.

[0073] In certain clinical situations, the catheter may wrongly turn into the jugular vein towards the head, i.e., towards beacon 120 represented by icon 410 on FIG. 4. In this situation, the catheter reaches the proximity of beacon 120 represented by icon 410 on FIG. 4, beacon signal 125 is detected at the tip of the catheter, and icon 410 turns red. The user retracts the catheter and when the catheter tip leaves the beacon region indicated by icon 410, icon 410 is grayed out.

[0074] In certain clinical situations, the catheter may wrongly turn into a contralateral vein towards the opposite arm, i.e., towards beacon 140 represented by icon 420 on FIG.4. In this situation, the catheter reaches the proximity of beacon 140 represented by icon 420 on FIG. 4, beacon signal 135 is detected at the tip of the catheter, and icon 420 turnsred. The user retracts the catheter and when the catheter tip leaves the beacon region indicated by icon 420, icon 420 is grayed out.

[0075] In one embodiment of the present invention, the intravascular ECG signal 155 detected at the tip of the catheter is continuously displayed 470 on the graphical user interface. When the catheter tip enters the region 430 of the SAN, the P- wave of the ECG signal increases in amplitude and when the catheter tip is proximal to the SAN, the intravascular ECG pattern is similar to pattern 480, as extensively documented in the literature.

[0076] In one embodiment of the present invention, only beacon electrode 120 is placed on the patient’s neck to detect when the intravascular device is advanced toward the patient’s head. In one embodiment of the present invention, only beacon electrode 140 is placed on the patient’s chest to detect when the intravascular device is advanced into the superior vena cava. In one embodiment of the present invention, one beacon is placed on the patient’s abdomen to detect when the intravascular device is advanced into the inferior vena cava. One or several beacon electrodes can be placed on the patient’s skin at different locations to detect the movement of an intravascular device in the patient’s vasculature beneath a beacon electrode.

[0077] In one embodiment of the present invention, a beacon is identified as active when the signal pattern corresponding to / generated by the beacon has been received by the system, independent of the intensity / amplitude of this signal.

[0078] In one embodiment of the present invention, the location of the device tip 165 is determined by also using the intensity of the beacon signal to estimate tip location: the stronger the beacon signal, the closer the device tip 165 is relative to the location of the signal generating beacon.

[0079] FIG. 5 illustrates an embodiment of a graphical user interface 500 displaying embodiments of beacon identification signals according to the present invention.

[0080] In one embodiment of the present invention, the simplified user interface 400 is displayed on the left-hand side of graphical user interface 500.

[0081] In one embodiment of the present invention, an exemplary binary identification code of beacon 120 is shown in window 510 to help the user recognize this code when the intravascular device is in the proximity of this beacon. In one embodiment of the present invention, an exemplary binary identification code of beacon 140 is shown in window 520 to help the user recognize this code when the intravascular device is in the proximityof this beacon. In one embodiment of the present invention, an exemplary ECG waveform 155 is shown in window 530 to help the user recognize signal 157 when the intravascular device is in the proximity of the sinoatrial node 150.

[0082] In one embodiment of the present invention, signal 540 received by the intravascular device from beacon 120 is displayed continuously. When the device tip enters the signal region 410 of beacon 120, waveform 545 is displayed. The user can visually compare waveform 545 with the exemplary beacon identification code 510 and, if they are similar, confirm the presence of the device tip in the proximity of beacon 120. In such a case, in one embodiment of the present invention, icon 410 is turned red by the system.

[0083] In one embodiment of the present invention, signal 550 received by the intravascular device from beacon 140 is displayed continuously. When the device tip enters the signal region 420 of beacon 1401, signal 555 is displayed. The user can visually compare waveform 555 with the exemplary beacon identification code 520 and, if they are similar, confirm the presence of the device tip in the proximity of beacon 140. In such a case, in one embodiment of the present invention, icon 420 is turned red by the system.

[0084] In one embodiment of the present invention, ECG signal 155 received by the intravascular device is displayed continuously 470. When the device tip enters the region 430 of the sinoatrial node, signal 480 is displayed. The user can visually compare waveform 480 with the exemplary beacon waveform 530 and, if they are similar, confirm the presence of the device tip in the proximity of or at the sinoatrial node.

[0085] In one embodiment of the present invention, field 590 of the graphical user interface 500 contains alpha-numeric information, system controls, and warnings.

[0086] FIG. 6A illustrates an embodiment of a method of encoding beacon signals with uniquely identifiable codes. In one embodiment of the present invention, Frequency Shift Keying (FSK) is used for frequency modulation of the alternating current (AC) carrier signal.

[0087] In one embodiment of the present invention, binary code 615 represents the identification code for beacon 120. In one embodiment of the present invention, AC signal 620 is modulated to reflect binary code 615. In one embodiment of the present invention, a higher frequency 625 is selected to represent the higher amplitude or binary value “1” of binary code 615 and a lower frequency 630 is selected to represent the lower amplitude or binary value “0” of binary code 615.

[0088] In one embodiment of the present invention, the gap between the higher and the lower frequencies is such as to allow for simple selective filtering of such frequencies without distortions.

[0089] In one embodiment of the present invention, the higher FSK modulation frequency 625 is 65 kHz and the lower FSK modulation frequency 630 is 55 kHz.

[0090] In one embodiment of the present invention, binary code 635 represents the identification code for beacon 140. In one embodiment of the present invention, the modulated AC signal 640 consists of a higher frequency 645 representing the higher amplitude or binary value “1” of binary code 635 and a lower frequency 650 representing the lower amplitude or binary value “0” of binary code 635.

[0091] In one embodiment of the present invention, frequencies 625 and 645 are equal and frequencies 630 and 650 are equal.

[0092] The binary identification codes for the different beacons must also comply with certain timing requirements as illustrated by the time axis 610. In one embodiment of the present invention, a beacon signal is emitted by a beacon 4 times / second, i.e., each 250 msec, for the beacon signal to be received and identified while the intravascular device is advanced through the vasculature at a customary speed.

[0093] Further, the binary identification codes for the different beacons must be different enough to allow for reliable, error-tol erant decoding.

[0094] In one embodiment of the present invention, beacon signal 620 consists of a high frequency burst 625 of 80 msec followed by a low frequency burst 630 of 80 msec and followed by another high frequency burst of 80 msec for a total of 240 msec. Assuming a frequency burst unit of 40 msec, the binary identification code for beacon 120 is, in this embodiment, “110011”.

[0095] In one embodiment of the present invention, beacon signal 640 consists of a high frequency burst 645 of 160 msec followed by a low frequency burst 650 of 40 msec and followed by another high frequency burst of 40 msec for a total of 240 msec. Assuming a frequency burst unit of 40 msec, the binary identification code for beacon 140 is, in this embodiment, “111101”.

[0096] In one embodiment of the present invention, beacons 120 and 140 are activated sequentially to minimize amount of energy injected into the body. First, a first beacon on the desired path of the intravascular device is turned on. Once the tip of the catheter is in the signal region of this first beacon, the following target beacon signal is turned on. Oncethe catheter tip enters the signal region of this second beacon, the first beacon signal is turned off.

[0097] FIG. 6B illustrates another embodiment of a method of encoding beacon signals by creating unique power spectrum characteristics, or power spectrum identities for each beacon. In one embodiment of the present invention, each beacon is identified by an AC signal of a single frequency, the signal frequency being different for each beacon. In one embodiment of the present invention, beacon 120 is identified by signal 660 of a higher frequency and beacon 140 is identified by signal 670 of a lower frequency.

[0098] In one embodiment of the present invention, the amplitudes and the single frequencies of signals 660 and 670 are selected in such a way as not to interfere with any physiological signals or with pacemaker signals. These amplitudes and frequencies allow for the required tissue penetration and are not influenced by electromagnetic radiations generally present in the operating room or at the patient’s bed. Furthermore, these amplitudes and frequencies delivered into the patient’s body comply with all applicable safety standard and FDA guidelines. The gap between the higher and the lower frequencies is such as to allow for simple and accurate selective filtering of such frequencies without signal distortions.

[0099] In one embodiment of the present invention, the higher frequency 660 is 65 kHz and the lower frequency 670 is 55 kHz.

[0100] FIG. 7 illustrates an embodiment of a block diagram 700 of a device and method for encoding beacon signals according to the present invention. In one embodiment of the present invention, frequency Shift Keying is used to modulate the frequency of signal carrier 620 with beacon code 615 that identifies beacon 120. Oscillator 710 generates an AC signal of preselected frequency 625. Oscillator 720 generates another AC signal of a different preselected frequency 630. Beacon signal code 615 is input to controller module 730. If amplitude “A” of beacon identification signal 615 is “high” or “1”, controller module 730 changes switch 740 to select oscillator 710. If amplitude “A” of beacon identification signal 615 if “low” or “0”, controller module 730 changes switch 740 to select oscillator 720. The resulting beacon signal 620 which is emitted by the beacon into the patient’s body is, thus, a frequency modulated signal of a beacon identification code.

[0101] In one embodiment of the present invention, the On / Off switch 750 allows for turning off signal generator 700 when it is not in use and to turn it on when it needs to generate beacon signals.

[0102] FIG. 8 illustrates an embodiment of a block diagram 800 of a device and method of extracting beacon signals from the signal received by receiver 180. In one embodiment of the present invention, at any one moment in time, the signal 170 received by receiver 180 through intravascular device 160 is a superposition of all beacon signals emitted in the patient’s body by all active natural and artificial beacons. Thus, each beacon signal must be individually extracted from signal 170 for further processing and interpretation.

[0103] In one embodiment of the present invention, a selective filter 810 is used to extract frequency modulated signal 620 generated by a beacon, e.g., by beacon 120.

[0104] In one embodiment of the present invention, an inverse notch filter 820 is used to extract a single frequency signal generated by a beacon, e.g., by beacon 140.

[0105] In one embodiment of the present invention, a selective filter is used to extract beacon signals generated by natural beacons, e.g., by the sinoatrial node as further describe herein.

[0106] In one embodiment of the present invention, selective filtering is used to extract only the frequency components contained in and characterizing a specific beacon signal. Inverse notch filter 820 constitutes an example of such selective filtering.

[0107] In one embodiment of the present invention, filter 810 is a pre-defined filter according to the signal characteristics of signal 620. In one embodiment of the present invention, filter 810 is a band-pass filter. In one embodiment of the present invention, filter 810 is an adaptive filter implemented in frequency domain.

[0108] Signal filters, e.g., filters 810 and 820 can be implemented in time domain, in frequency domain or in a combination of both domains. In one embodiment of the present invention, when implemented in frequency domain, the transformation of the signal from time domain into frequency domain is achieved using a digital signal processor (DSP) and a Fast Fourier Transform (FFT) algorithm.

[0109] FIG. 9 illustrates an embodiment of a block diagram 900 of a device and method of decoding received beacon signals. In one embodiment of the present invention, frequency (FKS) modulated signal 620, generated by beacon 120 and received by receiver 180, is input to signal demodulator 900. Upon receiving extracted signal 620, signaldemodulator 900 transforms signal 620 into code signal 615 that is used to identify beacon 120.

[0110] In one embodiment of the present invention, received and extracted signal 620 is simultaneously input to two band-pass or inverse notch filters 920 and 930. Filter 920 extracts the higher frequency present in modulated FSK signal 620. Filter 930 extracts the lower frequency present in modulated FSK signal 620. Envelope detector 940 detects if a higher frequency in signal 620 has been extracted. Envelope detector 950 detects if a lower frequency in signal 620 has been extracted. The decision circuit 960 outputs a high amplitude, or a “1”, if the envelope detector 940 has detected a higher frequency. The decision circuit 960 outputs a low amplitude, or a “0”, if the envelope detector 940 has detected a lower frequency. Thus, the signal at the output of demodulator 900 is a code signal that identifies a certain beacon, signal that was used to frequency modulate the signal generated by the beacon.

[0111] In the embodiment illustrated in FIG. 9, output signal 615 is the binary code identifier of beacon 120 and was used to frequency modulate signal 620 generated and emitted into the patient’s body by beacon 120.

[0112] FIG. 10 illustrates another embodiment 1010 of a device and method of extracting beacon signals according to the present invention. In one embodiment of the present invention, ECG signal 1030 is extracted from signal 170 by using band-pass filter 1010. Band-pass filter 1010 has a transfer function corresponding to the frequency spectrum of ECG signal 155.

[0113] In one embodiment of the present invention, filter 1010 is a selective filter, i.e., a filter that selects only pre-defined signal frequencies. Such a selective filter allows, for example, to selectively filter and emphasize signal frequencies corresponding to certain ECG waveform segments, e.g., frequencies corresponding to the P-wave and / or R-wave.

[0114] In one embodiment of the present invention, filter 1010 is a pre-defined filter according to the signal characteristics of the SAN beacon signal 157.

[0115] In one embodiment of the present invention, filter 1010 is an adaptive filter: the transfer functions changes in time by adapting itself to the variations in the characteristics of signal 157, for example as the catheter advances through the superior vena cava towards the sinoatrial node and the cavoatri al junction.

[0116] In one embodiment of the present invention, filter 1010 is an adaptive filter implemented in frequency domain. In another embodiment of the present invention, filter 1010 is an adaptive filter implemented in time domain.

[0117] FIG. 11 illustrates an embodiment of a device and method of binary encoding of a natural beacon signal. In one embodiment of the present invention, extracted ECG signal 1030 is overamplified (distorted) by amplifier 1120 such that the highest peaks 1137 are saturated and cut off by the high amplifications. Peak detector 1140 detects the saturated peaks in signal 1130 and outputs the binary signal 1150 with high amplitude value each time that a saturated peak has been detected. Thus, the resulting binary signal 1145 represents the binary identification code of the sinoatrial natural beacon.

[0118] In one embodiment of the present invention, selective filtering, over-amplification and peak-detection are used to create binary identification codes for other natural beacon signals, e.g., for signal 1355 on FIG. 13.

[0119] In one embodiment of the present invention, binary identification code 615 is used to identify beacon 120, binary identification code 635 is used to identify beacon 140, and binary identification code 1145 is used to identify beacon 150. Binary sequence detector 160 detects the binary sequences representing each binary identification code.Information processing module 340 associates a pre-saved identification number to each binary sequence detected by detector 360 and transmits it to information processing module 340. The identification number corresponding to the emitting beacon is then used to display the corresponding beacon as active on graphical user interface.

[0120] In one embodiment of the present invention, the identification number corresponding to an emitting beacon is generated based on the detection of the single frequency signal associated to the beacon, e.g., the detection of signal frequency 660 is associated to beacon 120 and the detection of frequency 670 to beacon 140.

[0121] FIG. 12 illustrates several natural beacons present in the human body. The brain 1230 generates electrical signals that can be detect by electroencephalography (EEG). The heart 1240 generates electrical signals that can be detect by electrocardiography (ECG). The diaphragm 1250 generates electrical signals that can be detect by electromyography (EMG). Skeletal muscles 1260 generate electrical signals that can be detect by electromyography (EMG).

[0122] In one embodiment of the present invention, intravascular device 160 receives at its distal end 165 electrical signal 170 and transmits it to receiver 180. Signal 170 is a superposition of different signals generated by the different natural beacons.

[0123] In one embodiment of the present invention, device 160 includes electrical sensors at its distal end. In one embodiment of the present invention, the electrical signals received by device 160 at its distal end 165 is transmitted to receiver 180 by a column of saline solution that fills the lumen of device 160. In one embodiment of the present invention, the electrical signals received by device 160 at its distal end 165 is transmitted to receiver 180 through a conductive wire inserted in the lumen of device 160.

[0124] In one embodiment of the present invention, data acquisition sub-system 200 separates and identifies different natural beacon signals received by receiver 180 as disclosed in the present invention. As device 160 is advanced through the patient’s vasculature, user interface sub-system 300 displays on graphical user interface 400 the location of the tip (distal end) 165 of device 160 according to the beacon signals received and to the proximity of the different natural beacons relative to the distal end 165 of device 160.

[0125] FIG. 13 illustrates a diagram 1300 of amplitude (A) 1305 vs. frequency (f) 1310 characteristics of natural beacon signals generated by muscles 1325, heart 1335, and brain 1355, by pacemakers 1345, and by an embodiment of artificial beacon signals 1365 according to the present invention.

[0126] In one embodiment of the present invention, diagram 1300 is divided into quadrants, each natural or artificial beacon belonging to one or more quadrants. Thus, beacon signals generated by muscles 1325 have power spectrum 1320 and belong to quadrants A4 / fl, A4 / f2, and A4 / f3. Beacon signals generated by the heart 1335 have power spectrum 1330 and belong to quadrants A3 / fl and A3 / f2. Beacon signals generated by a pacemaker 1345 have power spectrum 1340 and belong to quadrants A2 / f3 and A2 / f4. The beacon signals generated by the brain 1355 have power spectrum 1350 and belong to quadrant A2 / f3 and Al / fl. Beacon signals 1365 generated by artificial beacons according to the present invention have power spectrum 1360 and belong to quadrant Al / f4.

[0127] In one embodiment of the present invention, the automated discrimination and classification of signal patterns generated by and received from different beacons is greatly simplified by associating a beacon signal to one of the clusters / quadrants ofdiagram 1300. Selective filters 810, 820, and 1010 are implemented for each signal based on the power spectrum of such signal. Further, if, for example, a signal received by receiver 180 has a signal component of amplitude and frequency belonging to quadrant Al / f4, this signal component is identified as having been generated by an artificial beacon.

[0128] FIG. 14 illustrates an embodiment of intravascular navigation using two natural beacon signals according to the present invention: signal 1355 generated by the brain and signal by the heart 155. Depending on the location of the device tip 165, the received signal contains more predominantly signals generated by the brain or signals generated by the heart. The received signals also increase in intensity when the device tip approaches the natural beacon generating the signal.

[0129] FIG. 15 illustrates an embodiment of a device and method of processing signal 170 and separating and identifying signals 1355 generated by the brain and signals generated by the heart 155.

[0130] In one embodiment of the present invention, the herein disclosed device and method is based on diagram 1300 and makes use of the differences in amplitude and frequency between brain signals 1355 and heart signal 1555 to identify, discriminate, and separate them. For example, brain signals (EEG) 1355 have an amplitude in the range lOpV to 500pV and frequencies in the range of 0.05 to 100 Hz (including Gamma waves) with amplitude and power spectrum variations indicative of certain locations in the brain and of certain brain activities. ECG signals 155 have amplitudes in the range of 500 pV to 5 mV and frequencies in the range of 0.05 to 150 Hz with amplitudes and power spectrum variations indicative of certain locations in the heart, for example at the cavoatrial junction in the proximity of the sinoatrial node (enlarged P-wave), inside the ventricles (RST complex), etc.

[0131] In one embodiment of the present invention, amplifier 1520 amplifies signal 170 to allow for better processing of the lower amplitudes of brain signal 1355. In one embodiment of the present invention, amplification of signal 170 by amplifier 1520 is such that the high amplitudes of signal 1355 are saturated. This allows for implementing binary coding of the EEG signal, as disclosed on FIG. 11 for the ECG signals, and better discrimination between signals.

[0132] In one embodiment of the present invention, selective filter 1530 selects significant brain signal components that will be further used to estimate the location of the device tip 165 in the proximity of the brain, for example in the internal jugular vein. In one embodiment of the present invention, filter 1530 is also an adaptive filter that adapts itself to the changes in waveform 1355 as the intravascular device advance towards the brain.

[0133] In one embodiment of the present invention, selective filter 1010 selects significant heart signal components, e.g., the P-wave, that will be further used to estimate the location of the device tip 165 in the proximity of the heart, for example at the cavoatrial junction. In one embodiment of the present invention, filter 1010 is also an adaptive filter that adapts itself to the changes in waveform 155 as the intravascular device advance towards the heart.

[0134] In one embodiment of the present invention, filters 1530 and 1010 are implemented in frequency domain. In one embodiment of the present invention, filters 1530 and 1010 are implemented in time domain.

[0135] FIG. 16 illustrates an embodiment 1600 of a graphical user interface for intravascular device navigation using brain and heart natural beacons as illustrated on FIG. 14. In one embodiment of the present invention, the desired trajectory 1610 of the tip 165 of the intravascular device descends towards the heart. However, it may happen that the device tip 165 advances towards the brain inside the jugular vein on trajectory 1615

[0136] In one embodiment of the present invention, the device and method illustrated on FIG. 15 identifies and continuously displays signal 1640. When the device tip advances on trajectory 1615 towards the brain, signal 1635 is displayed. The user can compare signal 1635 with an exemplary signal template 1630 to determine if the catheter advances towards the brain. In such a case, the user retracts the intravascular device until signal 1635 is not visible anymore and readvances the catheter on trajectory 1610. The device and method illustrated on FIG. 15 identifies and continuously displays ECG signal 470. When the device tip 165 is in the proximity of the sinoatrial node, signal 480 is displayed. The user can compare signal 480 with the exemplary signal template 530 to confirm the device tip location.

[0137] In one embodiment of the present invention, alpha-numeric field 1680 contains system controls and displays warning and information pertinent information related to the case at hand.

[0138] FIG. 17 illustrates an embodiment 1700 of an apparatus according to the present invention that uses artificial beacons of different energy types for intravascular device navigation. In one embodiment of the present invention, the apparatus contains one or several beacon signal emitters 1740 and 1760 and one or several beacon signals receivers 1710. An intravascular device 1720 is advanced through the patient’s vasculature, receives at its distal end 1730 superimposed signals 1735 emitted by one or a plurality of beacons, is connected to signal receiver 1710 by connective element 1715, and transmits the received signals 1735 to receiver 1710.

[0139] In one embodiment of the present invention, beacon 1750 is a visible light emitting beacon. Similarly to a lighthouse, the beacon emits into the patient’s body a visible light of a certain pattern and periodicity in such a way as to uniquely identify the emitting beacon. The visible light generator 1740 is connected to beacon 1750 using optical fiber 1745. Beacon 1750 is in the proximity of the patient’s skin in such a way as to allow the emitted light to enter the patient’s body. Correspondingly, in this embodiment, the intravascular device 1720 has a light sensor integrated at its distal tip 1730 and transmits the beacon light signal from the sensor to receiver 1710 via an optical fiber passed either through the inner lumen of the device or integrated in the device wall.

[0140] In one embodiment of the present invention, electromagnetic radiation of different wavelengths is used, for example Near-Infrared Light (NIR). Beacon 1770 emits NIR light of a certain pattern and periodicity, for example using a light diode, and the optical fiber contained in device 1720 transmits the received NIR light from sensor 1730 to receiver 1710. Generator 1760 is connected to beacon 1770 using optical fiber 1765.

[0141] In one embodiment of the present invention, the visible or NIR light received by receiver 1710 is used to characterize the body tissue and blood through which the light has travelled from the beacon to the sensor. Thus, additional information about the device tip location is obtained.

[0142] In one embodiment of the present invention, generator 1760 creates a fixed or variable magnetic field around beacon 1785 of a certain pattern and periodicity. A magnetic el em ent / sensor at the distal tip 1730 of device 1720 senses the magnetic field generated by beacon 1785. The magnetic element / sensor is connected to receiver 1710 viaelectrical wires passed through the lumen of device 1720 or integrated into the device wall. Thus, receiver 1710 receives an electrical signal corresponding to the magnetic field and its variations sensed by the sensor at the distal tip 1730 of device 1720.

[0143] FIG. 18 illustrates an embodiment 1800 of the graphical user interface of the apparatus according to the present invention. In one embodiment of the present invention, three artificial beacons are used for intravascular device navigation as illustrated on FIG.17.

[0144] In one embodiment of the present invention, these three beacons are represented on the display of the graphical user interface using different icons (different symbols and colors), such they are easily and unmistakably identifiable: 1804, 1806, 1808.

[0145] In one embodiment of the present invention, the user places physical beacons on the patient’s body at relevant locations for navigation. The user then drags and drops each of the beacon icons displayed on the screen to a corresponding location onto the displayed image of the patient’s body, for example on FIG. 18: icon 1804 to location 1820, icon 1806 to location 1822, and icon 1808 to location 1824.

[0146] In one embodiment of the present invention, a unique identification is internally associated with each of the represented beacons, e.g., a binary code, a signal waveform, AC signal frequency. Each of the beacons transmits a beacon signal into the patient body corresponding to its unique identification, as disclosed herein.

[0147] In one embodiment of the present invention, each identification signal defined for each beacon is displayed on the graphical user interface for easy identification by the user: signal 1842 represents the unique identification or signature signal of the beacon represented by icon 1804 at location 1820 on the patient’s image; signal 1840 represents the unique identification or signature signal of the beacon represented by icon 1808 at location 1824 on the patient’s image; and signal 1844 represents the unique identification or signature signal of the beacon represented by icon 1806 at location 1822 on the patient’s image.

[0148] In one embodiment of the present invention, the signals received from each beacon are processed as disclosed herein and displayed on the graphical user interface in real-time: signal 1862 for the beacon at location 1820, signal 1860 for the beacon at location 1824, and signal 1864 for the beacon at location 1822.

[0149] In one embodiment of the present invention, the distal end / tip of the intravascular device is represented on the graphical user interface by dot 1835. As illustrated on FIG.18, as the device is advanced through the vasculature, it can go towards any of the three beacons placed on the patient’s body. If the device advances towards the beacon represented at location 1820 and starts receiving the beacon signal of this beacon, then signal 1862 is displayed on the screen, dot 1835 is displayed over the corresponding beacon icon 1820, and the color of icon 1820 changes to indicate that the icon is active. Similarly, if the device advances towards the beacon represented at location 1824 and starts receiving the beacon signal of this beacon, then signal 1860 is displayed on the screen, dot 1835 is displayed over the corresponding beacon icon 1824, and the color of icon 1824 changes to indicate that the icon is active. Finally, if the device advances towards the beacon represented at location 1822 and starts receiving the beacon signal of this beacon, then signal 1864 is displayed on the screen, dot 1835 is displayed over the corresponding beacon icon 1822, and the color of icon 1822 changes to indicate that the icon is active. Thus, the user is informed about the direction and the estimated location of the intravascular device tip within a region of one of the beacons placed on the patient’s body.

[0150] FIG. 19 illustrates an embodiment of an algorithm to process, analyze, identify, classify, and display beacon signals and intravascular device tip location as illustrated on FIG. 4.

[0151] In one embodiment of the present invention, signal 170 received by receiver 180 is, at any one moment in time, a superposition of several beacon emitted signals. In the embodiment illustrated on FIG. 19 and as previously disclosed herein, received signal 170 is the superposition of ECG signal 155 emitted by the heart and its sinoatrial node 150, of single frequency beacon signal 660 emitted by beacon 120, and of single frequency beacon signal 670 emitted by beacon 140.

[0152] In one embodiment of the present invention, signal 170 is amplified by amplifier 1915 and then input to three bandpass filters. In one embodiment of the present invention, filter 1920 is a selective filter that extracts the ECG signal and outputs signal 1932, filter 1925 is a selective filter that extracts beacon signal 660 and outputs signal 1934, and filter 1930 is a selective that extracts beacon signal 670 and outputs signal 1936. Selective filter 1925 is centered around the beacon signal frequency characterizing beacon 120. Selective filter 1930 is centered around the beacon signal frequency characterizing beacon 140

[0153] In one embodiment of the present invention, selective filter 1920 extracts from the power spectrum of signal 1932 only spectral components of characteristic of waves P and R of the ECG signal.

[0154] In one embodiment of the present invention, selective filter 1920 is also an adaptive filter that changes accordingly as the P-wave changes when an intravascular device is advanced through the central vena cava towards the cavoatrial junction and the sinoatrial node.

[0155] In one embodiment of the present invention, filters 1920, 1925, 1930 are implemented in time domain. In one embodiment of the present invention, filters 1920, 1925, 1930 are implemented in frequency domain.

[0156] In one embodiment of the present invention, filters 1920, 1925, 1930 are implemented in software. In one embodiment of the present invention, the filters are implemented in hardware / firmware.

[0157] In one embodiment of the present invention, signal 1932 is overamplified by amplifier 1940 such that the R-wave and the P-wave corresponding to the proximity of the sinoatrial node in region 430 are saturated and can be easily identified.

[0158] In one embodiment of the present invention, the resulting saturated signal 1955 is input to peak detector 1960 that detects saturated peaks in signal 1955 and outputs binary signal 1965, whereby binary signal 1965 has a high amplitude or a value “1” each time a saturated peak in the input signal has been detected.

[0159] In one embodiment of the present invention, the algorithm for peak detection 1960 is implemented in software. In one embodiment of the present invention, the peak detection algorithm is implemented in hardware / firmware.

[0160] In one embodiment of the present invention, signal 1965 is input to binary sequence detector 1970 that detects the sequence of two consecutive high values in signal 1965 and outputs a high signal 1975 value or a “1” each time the sequence of two consecutive high amplitude values have been detected in signal 1965.

[0161] In one embodiment of the present invention, the algorithm for binary sequence detector 1970 is implemented in software. In one embodiment of the present invention, the binary sequence detector algorithm is implemented in hardware / firmware.

[0162] In one embodiment of the present invention, signal 1934 is input to envelope detector 1945. Envelope detector 1945 outputs a high amplitude signal 1977 or a value “1” each time a signal of frequency corresponding to beacon 120 is detected at its input. In one embodiment of the present invention, signal 1936 is input to envelope detector1950. Envelope detector 1950 outputs a high amplitude signal 1980 or a value “1” each time a signal of frequency corresponding to beacon 140 is detected at its input.

[0163] In one embodiment of the present invention, the algorithms for envelope detectors 1945 and 1950 are implemented in software. In one embodiment of the present invention, the algorithms for the envelope detectors are implemented in hardware / firmware.

[0164] In one embodiment of the present invention, signals 1975, 1977, and 1980 are input to decision module 1985. Under consideration of system status and control information 1990, using switch 1988 decision module turns on icon 430 to green on the graphical user interface on FIG. 4 if signal 1975 is received, icon 410 to red if signal 1977 is received, or icon 420 to red if signal 1980 is received. Only a single icon can be turned on at one time. In one embodiment of the present invention, decision module 1985 grays out the corresponding icon when the device exits the active region of the corresponding beacon. If no beacon signal has been received, decision module 1985 grays out all displayed icons.

[0165] In one embodiment of the present invention, system status and control information are stored in the system memory and includes: leads-off electrode information, surface ECG waveforms, intravascular ECG waveforms, beacon identification signals, history of the trajectory of the intravascular device recorded as a sequence of beacons in the proximity of which the device has passed.

[0166] In one embodiment of the present invention, exemplary signal waveforms / pattems 510, 520, and 530 are stored in memory and automatically compared against received ECG and beacon signals. Warning messages are displayed if, for example, signal 1975 is received by decision module 1985 but signal 1932 does not correlate to signal 530. In one embodiment of the present invention, the comparison between signals is accomplished by computing the correlation coefficient of the two signals. If correlation coefficient is below a certain threshold, the signals do not correlate with each other.

Claims

APPARATUS AND METHOD FOR INTRAVASCULAR NAVIGATIONUSING BEACON SIGNALSClaims

1. An apparatus for navigating intravascular devices characterized in that said apparatus comprises:one or more means (for example, 175) to electrically, optically, or otherwise connect said apparatus to the proximal end of one or more intravascular or extracorporeal devices, whereby said devices have elongated bodies with a distal end that can be attached to, inserted into, or otherwise be connected to a patient's body in order to receive uniquely identifiable beacon signals at their distal end and transmit said signals to said apparatus connected at their proximal end;one or more beacon signal receivers (for example, 230) that are configured to receive uniquely identifiable beacon signals from a plurality of uniquely identifiable signal sources or beacons located on, within, or in the proximity of the patient's body through said intravascular or extracorporeal devices;one or more data, signal, and information processing modules (for example, 240, 260) that are configured to process the received uniquely identifiable beacon signals and identify the corresponding source beacon of each of these signals;one or more data, signal, and information processing modules (for example, 340, 360) that are configured to track in real time the path of the distal end of said intravascular device or devices relative to the location or locations of the identified transmitting beacon or beacons as the distal end of the intravascular device or devices approaches, leaves, or passes in the spatial proximity of said beacon or beacons during intravascular navigation; one or more interface modules (for example, 290) that are configured to output the results of processing and identifying the received beacon signals;

2. The apparatus for navigating intravascular devices according to claim 1, characterized in that said received uniquely identifiable beacon signals are generated by natural or biological generators, transmitters, or beacons located inside the patient's body (for example, FIG. 12).

3. The apparatus for navigating intravascular devices according to claim 1, characterized in that said received uniquely identifiable beacon signals are generated by artificial signal generators, transmitters, or beacons (for example, 110) located inside, onto or in the proximity of the patient's body.

4. The apparatus for navigating intravascular devices according to claim 1, characterized in that said beacon signals can be identified by their unique frequency spectra and / or unique amplitude ranges (for example, 1300).

5. The apparatus for navigating intravascular devices according to claim 1, characterized in that a received uniquely identifiable beacon signal can be identified by a unique code encoded in said beacon signal (for example, FIGS. 7 and 9);

6. The apparatus for navigating intravascular devices according to claim 5, characterized in that said apparatus uses one or more signal amplifiers (for example, 1940) to saturate a beacon signal (for example, 1955) and one or more peak detectors (for example, 1960) to transform the saturated beacon signal into a binary sequence or code (for example, 1965).

7. The apparatus for navigating intravascular devices according to claim 5, characterized in that said apparatus uses one or more envelope detectors (for example, 1970) to detect the presence of a beacon signal code in the received signal.

8. The apparatus for navigating intravascular devices according to claim 5, characterized in that said apparatus uses one or more binary sequence detectors (for example, 1970) to detect the presence of a beacon signal code in the received signal.

9. The apparatus for navigating intravascular devices according to claim 4, characterized in that said apparatus is configured to identify a unique frequency spectrum of each beacon signal using selective filtering of the frequency spectra (for example, 1530).

10. The apparatus for navigating intravascular devices according to claim 9, characterized in that said selective filtering covers the frequency spectrum of electroencephalogram signals emitted by the brain.

11. The apparatus for navigating intravascular devices according to claim 9, characterized in that said selective filtering covers the frequency spectrum of electrocardiogram signals emitted by the heart.

12. The apparatus for navigating intravascular devices according to claim 9, characterized in that said selective filtering covers the frequency spectrum of electromyogram signals emitted by body muscles.

13. The apparatus for navigating intravascular devices according to claim 9, characterized in that said selective filter of the frequency spectra is an inverse notch filter (for example, 820).

14. The apparatus for navigating intravascular devices according to claim 4, characterized in that said apparatus is configure to identify unique amplitude ranges of each beacon signal using selective amplification of a beacon signal (for example, 1520).

15. The apparatus for navigating intravascular devices according to claim 14, characterized in that said selective amplification covers the range of electroencephalogram signals emitted by the brain.

16. The apparatus for navigating intravascular devices according to claim 14, characterized in that said selective amplification covers the range of electrocardiogram signals emitted by the heart.

17. The apparatus for navigating intravascular devices according to claim 14, characterized in that said selective amplification covers the range of electromyogram signals emitted by body muscles.

18. The apparatus for navigating intravascular devices according to claim 4, characterized in that said apparatus is configured to determine the spatial proximity of a beacon relative to the distal end of said intravascular device by automated identification of said beacon's uniquely identifiable frequency spectra / amplitude ranges.

19. The apparatus for navigating intravascular devices according to claim 5, characterized in that said is configured to determine the spatial proximity of a beacon relative to the distal end of said intravascular device by automated identification of said beacon's uniquely identifiable code independently of the intensity / amplitude / strength of the said signal.

20. The apparatus for navigating intravascular devices according to claim 1, characterized in that said apparatus comprises a graphical user interface that is configured to display one or more of the following elements (for example, FIG. 4):a graphic representation (for example, 400) indicating at least one location of interest on the trajectory of an intravascular device, for example, the location of an artificial beacon placed on the patient's body (for example, 410) and the location of a natural beacon (for example, 430);the real time location of the distal end (for example, 165) of the intravascular device when said distal end passes in the proximity of a represented beacon;

21. The apparatus for navigating intravascular devices according to claim 20, characterized in that said graphical user interface is configured to display the path (for example, 450) of the distal end of the intravascular device passing in the proximity of represented signal beacons (for example, FIG. 4):

22. The apparatus for navigating intravascular devices according to claim 20, characterized in that said graphical user interface is configured to display one or more of the following elements (for example, FIG. 5):templates of beacon signals for easier recognition by the user, for example in FIG. 5, beacon signal template (510) for artificial beacon (410) placed on the patient's neck;real time traces of received beacon signals, for example in FIG. 5, signal trace (for example, 540) for artificial beacon (410).

23. The apparatus for navigating intravascular devices according to claim 20, characterized in that said graphical user interface is configured to notify the user when the distal end of the intravascular device is in the proximity of represented beacon.

24. An apparatus for navigating intravascular devices characterized in that said apparatus is configured to cooperate with one or more apparatuses for navigating intravascular devices according to Claim 1 and comprises:one or more means (for example, 210) to electrically, optically, or otherwise connect said apparatus to the proximal end of one or more intravascular or extracorporeal devices, whereby said devices have elongated bodies with a distal end that can be attached to, inserted into, or otherwise be connected to a patient's body in order to transmit uniquely identifiable beacon signals generated by said apparatus into the patient's body;one or more beacon signal generators and transmitters (for example, 220) that are configured to generate uniquely identifiable beacon signals (for example, FIG. 6A) and to transmit these signals into the patient's body though one or more said intravascular or extracorporeal devices connected to said apparatus;one or more control modules (for example, 250) that are configured to control the generation and transmission of said uniquely identifiable beacon signals;one or more interface module (for example, 290) that are configured to communicate control information related to the generation of said uniquely identifiable beacon signals.

25. The apparatus for navigating intravascular devices according to claim 24, characterized in that said uniquely identifiable beacon signals transmitted into the body are configured to be identifiable using a unique code assigned to each beacon and encoded into each corresponding beacon signal (for example, FIG. 7);

26. The apparatus for navigating intravascular devices according to claim 24, characterized in that the uniquely identifiable beacon signals transmitted into the body by said apparatus have energy levels and frequency spectra in order to comply with all applicable safety standards and guidelines and to not interfere with physiological or pacemaker signals (for example, 1360).

27. The apparatus for navigating intravascular devices according to claim 26, characterized in that said energy levels determine the depths at which beacons transmit said uniquely identifiable beacon signals into the body.

28. The apparatus for navigating intravascular devices according to claim 26, characterized in that the energy of the uniquely identifiable signals transmitted into the body iselectric, magnetic, electromagnetic, optic, acoustic or a combination thereof (for example, FIG.17).

29. The apparatus for navigating intravascular devices according to claim 26, characterized in that the uniquely identifiable signals transmitted into the body have an alternating current intensity of less than 2.5 mA rms.

30. The apparatus for navigating intravascular devices according to claim 26, characterized in that the uniquely identifiable signals transmitted into the body have an alternating current frequency spectrum of less than 100 kHz.

31. A method for navigating intravascular devices, characterized in that said method uses the apparatus of Claim 1 and comprises the following steps:connecting the proximal end of an intravascular device to the apparatus for navigating intravascular devices according to claim 1 and advancing the distal end of said intravascular device within the patient's vasculature (for example, FIG. 14); receiving uniquely identifiable beacon signals emitted by natural or artificial beacons (for example, 1355 or 1365) through said intravascular device, whereby said signals are sensed at the distal end of said intravascular devices and transmitted through the intravascular device to its proximal end connected to the apparatus according to claim 1;processing said received beacon signals and identifying the corresponding source beacon or beacons by decoding the unique identification code or codes encoded in each of such beacon signals;determining, based on the identification of the source beacon or beacons, if the distal end of the intravascular device is in the proximity of such identified source beacon or beacons as the intravascular device advances within the patient's vasculature;displaying on a graphical user interface or otherwise communicating the location information regarding the distal end of said intravascular device.

32. The method for navigating intravascular devices according to claim 31, characterized in that said comprises the following steps:tracking the navigation path of the distal end of said intravascular device with respect to the location of identified artificial or natural beacon or beacons;displaying on a graphical user interface or otherwise communicating the navigation path information regarding the distal end of said intravascular device.

33. The method for navigating intravascular devices according to claim 31, characterized in that said received natural beacon signals are generated and emitted by the brain (for example, 1355).

34. The method for navigating intravascular devices according to claim 31, characterized in that said received natural beacon signals are generated and emitted by body muscles (for example, 1325).

35. The method for navigating intravascular devices according to claim 31, characterized in that said received natural beacon signals are generated and emitted by the heart (for example, 1335).

36. The method for navigating intravascular devices according to claim 31, characterized in that artificial uniquely identifiable beacon signals are generated and transmitted into the patient's body by the apparatus for navigating intravascular devices according to claim 24 through said intravascular or extracorporeal devices connected to said apparatus.

37. The method for navigating intravascular devices according to claim 36, characterized in that said beacon signals are delivered into the body one or more beacons at a time, as the intravascular device navigation progresses through the vasculature, in order to minimize the amount of energy delivered into the patient's body at any one time.

38. The method for navigating intravascular devices according to claim 36, characterized in that said uniquely identifiable beacon signals are transmitted by the apparatus according to claim 22 into the patient's body through extracorporeal devices placed on the patient's skin at locations of interest for intravascular device navigation (for example, FIG. 4).

39. The method for navigating intravascular devices according to claim 38, characterized in that a said extracorporeal device is placed on the patient's chest in order to detect when the distal end of said intravascular device navigates towards or in the proximity of the heart.

40. The method for navigating intravascular devices according to claim 38, characterized in that a said extracorporeal device is placed on the patient's neck in order to detect when the distal end of said intravascular device navigates in the blood vessels in the neck.

41. The method for navigating intravascular devices according to claim 38, characterized in that a said extracorporeal device is placed on the patient's abdomen in order to detect when the distal end of said intravascular device navigates in the abdominal blood vessels.

42. The method for navigating intravascular devices according to claim 31, characterized in that said method comprises the step of generating a visual real-time indication when the distal end of an intravascular device is in the proximity of a beacon on the desired navigation path of the intravascular device (for example, 430 on FIG. 4) and / or a different visual indication when the distal end of an intravascular device is in the proximity of a beacon on an undesired navigation path (for example, 410 on FIG. 4).

43. The method for navigating intravascular devices according to claim 31, characterized in that said method comprises the following steps (for example, FIG. 19):receiving a signal (for example, 170) from the distal end of an intravascular device containing a superposition of one or more beacon signals, for example: a signal transmitted by a natural beacon (for example, 155) and a signal transmitted by an artificial beacon placed on the patient's skin (for example, 660);selectively filtering said received signal (for example, 1920) to separate and extract individual beacon signals from the received superposition of signals, if they are present in said received signal, for example, a signal generated by a natural beacon (for example, 1932) and a signal generated by an artificial beacon (for example, 1934);using signal decoding means to recognize and identify beacon signals that are present in said received signal based on unique codes encoded in each of the beacon signals (for example, 1970);deciding if the distal end of the intravascular device is in the proximity of an identified beacon (for example, decision module 1985).

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