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WO2023158603A1 - Ablation par ultrasons guidée par échos d'impulsion, procédé acoustique de détection d'orientation et de proximité des tissus d'un cathéter d'ablation par ultrasons - Google Patents

Ablation par ultrasons guidée par échos d'impulsion, procédé acoustique de détection d'orientation et de proximité des tissus d'un cathéter d'ablation par ultrasons Download PDF

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Publication number
WO2023158603A1
WO2023158603A1 PCT/US2023/012884 US2023012884W WO2023158603A1 WO 2023158603 A1 WO2023158603 A1 WO 2023158603A1 US 2023012884 W US2023012884 W US 2023012884W WO 2023158603 A1 WO2023158603 A1 WO 2023158603A1
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Prior art keywords
pulse
echo
tissue
hiu
ablation catheter
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English (en)
Inventor
David Giraud
Babak NAZER
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Oregon Health and Science University
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Oregon Health and Science University
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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N7/00—Ultrasound therapy
    • A61N7/02—Localised ultrasound hyperthermia
    • A61N7/022—Localised ultrasound hyperthermia intracavitary
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B2218/00—Details of surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B2218/001—Details of surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body having means for irrigation and/or aspiration of substances to and/or from the surgical site
    • A61B2218/002—Irrigation
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N7/00—Ultrasound therapy
    • A61N2007/0073—Ultrasound therapy using multiple frequencies
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N7/00—Ultrasound therapy
    • A61N2007/0086—Beam steering
    • A61N2007/0095—Beam steering by modifying an excitation signal

Definitions

  • Embodiments herein relate to a high-intensity ultrasound ablation catheters.
  • High-intensity ultrasound ablation catheters have various medical applications including treating cardiac conditions such as arrhythmias as well as treating cancer and tumors in other organs.
  • Such catheters use sound pressure waves in the frequency range of 20 KHz to 200 MHz to create thermal ablation lesions in subsurface regions without affecting intervening tissues and blood vessels.
  • the ultrasound energy induces molecular vibration and friction, resulting in absorptive heating and ultimately necrosis by thermal coagulation in the target tissue.
  • Increases in tissue temperature which are proportional to delivered acoustic energy, are achieved by controlling the ultrasound power and wavelength.
  • FIG. 1 depicts a tip of an example ultrasound ablation catheter in accordance with various embodiments.
  • FIG. 2A depicts an example pressure map 200 of the ultrasound ablation catheter 100 of FIG. 1 in an x-z plane, in accordance with various embodiments.
  • FIG. 2B depicts an example pressure map 210 of the ultrasound ablation catheter of FIG. 1 in a y-z plane, in accordance with various embodiments.
  • FIG. 3A depicts an example of an ultrasound ablation catheter which is poorly oriented relative to tissue, in accordance with various embodiments.
  • FIG. 3B depicts an example of an ultrasound ablation catheter which has an ideal orientation relative to tissue, in accordance with various embodiments.
  • FIG. 3C depicts another example of an ultrasound ablation catheter which has an ideal orientation relative to tissue, in accordance with various embodiments.
  • FIG. 3D depicts another example of an ultrasound ablation catheter which has an ideal orientation relative to tissue, in accordance with various embodiments, where the catheter includes an anchor 331 .
  • FIG. 4A depicts a trace of an amplitude of a pulse-echo waveform versus time for an ultrasound ablation catheter having the poor orientation of FIG. 3A, in accordance with various embodiments.
  • FIG. 4B depicts a trace of an amplitude of a pulse-echo waveform versus time for an ultrasound ablation catheter having the ideal orientation of FIG. 3B, in accordance with various embodiments.
  • FIG. 5 depicts a plot of a pulse-echo amplitude as a function of a degree of tissue contact, in accordance with various embodiments.
  • FIG. 6A depicts an example system for operating an ultrasound ablation catheter in a pulse-echo mode or a therapy mode, in accordance with various embodiments.
  • FIG. 6B depicts an example data processing system consistent with FIG. 6A, in accordance with various embodiments.
  • FIG. 7 A depicts a flowchart of an example process for operation an ultrasound ablation catheter, in accordance with various embodiments.
  • FIG. 7B depicts a flowchart of an implementation of the example process of FIG. 7A, in accordance with various embodiments.
  • FIG. 8A depicts waveforms used to generated a series of pulses of an ultrasound ablation catheter in a pulse-echo mode, in accordance with various embodiments.
  • FIG. 8B depicts a pressure pulse generated by an ultrasound ablation catheter consistent with FIG. 8A, in addition to a corresponding echo pulse, in accordance with various embodiments.
  • Coupled may mean that two or more elements are in direct physical or electrical contact. However, “coupled” may also mean that two or more elements are not in direct contact with each other, but yet still cooperate or interact with each other.
  • a phrase in the form “A/B” or in the form “A and/or B” means (A), (B), or (A and B).
  • a phrase in the form “at least one of A, B, and C” means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B and C).
  • a phrase in the form “(A)B” means (B) or (AB) that is, A is an optional element.
  • the description may use the terms “embodiment” or “embodiments,” which may each refer to one or more of the same or different embodiments.
  • Ultrasound ablation catheters have various applications including those in the biomedical field.
  • high-intensity focused ultrasound can be used as a non-invasive therapy that uses focused ultrasound waves to thermally ablate tissue.
  • Example scenarios include treating uterine fibroids, prostate cancer, tumors and heart tissue responsible for atrial fibrillation, as well as alleviating pain from bone cancer.
  • the ultrasonic treatment is guided by imaging.
  • the high intensity ultrasound (HIU) ablation catheter has demonstrated the ability to create large, necrotic lesions while sparing surface tissue adjacent to the device.
  • the HIU catheter is positioned to the desired lesion location using fluoroscopy and 2D diagnostic ultrasound imaging guidance.
  • the catheter may be inserted into a large blood vessel such as in the groin, neck or arm, for example.
  • a large blood vessel such as in the groin, neck or arm, for example.
  • the techniques provided herein address the above and other issues.
  • the techniques provide a new ultrasound-based guidance method, which uses the HIU crystal itself and a custom pulse-echo operation and signal processing technique.
  • HIU catheter position and orientation are manipulated based on real-time signal processing and display of the tissue surface reflected wave.
  • the transducer and tissue surface are aligned to be parallel. Once aligned, the lesion is predicted to form in a direction perpendicular to the tissue surface in contact with the HIU catheter.
  • the catheter is operated in a therapy mode to form one or more lesions.
  • the technique could be extended as well to predict “off-axis” lesions that are not perpendicular to the tissue-catheter surface. Moreover, the technique is feasible without the need for a separate, dedicated imaging transducer.
  • FIG. 1 depicts a tip of an example ultrasound ablation catheter 100 in accordance with various embodiments.
  • the catheter includes an ablation transducer 110 and an internal irrigation balloon 120. During the energizing of the transducer, it may become heated.
  • the internal irrigation balloon allows the transducer to be cooled by contacting the transducer subassembly with a fluid such as saline.
  • the fluid for cooling the transducer may be flushed past the transducer subassembly from a lumen 115 in the catheter (see e.g., FIG. 2A).
  • the fluid used for cooling the transducer can exit the catheter tip through a one or more apertures, not shown.
  • the transducer operates at 5, 6.5 or 8 MHz and has a single element. Frequencies below 5 MHz are unlikely to yield thermal effects, and above 8 MHz will likely generate shallow lesions.
  • the transducer size can be, e.g., 3 x 5 mm, 4 x 4 mm or 4 x 5 mm (to accommodate a 9-12 Fr catheter system). This refers to a catheter having an inner diameter of 9 Fr or 3 mm and an outer diameter of 12 Fr or 4 mm.
  • the transducer can operate at a power of 20 W, 30 W or 36 W, for example. A power >36 W typically results in unacceptable acoustic reflections.
  • the duration of operation in the therapy mode can be, e.g., 30 sec, 60 sec or 120 sec.
  • FIG. 2A depicts an example pressure map 200 of the ultrasound ablation catheter 100 of FIG. 1 in an x-z plane, in accordance with various embodiments.
  • the ablation transducer 110 and a lumen 115 are also depicted.
  • Ultrasound (US) transducers are devices which emit acoustic energy at ultrasound frequencies, e.g., >20 kHz.
  • One example of a transducer is a piezo-electric element which converts electrical signals into mechanical vibrations in a transmit mode, and which performs a reverse process by converting mechanical vibrations into electrical signals in a receive mode.
  • the transducer has a propagation axis in the z direction which has the greatest intensity.
  • the color or shading of the map corresponds to a peak negative pressure (PNP) which ranges between zero and a maximum value (Max).
  • FIG. 2B depicts an example pressure map 210 of the ultrasound ablation catheter of FIG. 1 in a y-z plane, in accordance with various embodiments.
  • the ultrasound ablation catheter 100 includes the transducer 110 and the lumen 115. There is a primary region 230 of highest intensity, along with second and third regions of lower intensity.
  • FIG. 3A depicts an example of an ultrasound ablation catheter which is poorly oriented relative to tissue, in accordance with various embodiments.
  • the catheter may be in a blood pool 300 in the body adjacent to a target tissue 315 which is the subject of the therapy.
  • An interface 310 between the blood pool and the tissue is depicted.
  • a longitudinal axis 320 of the catheter is angled and nonparallel relative to the interface, which is parallel to the y axis in this example.
  • the acoustic reflection from the blood-tissue interface arises from a mis-match of material acoustic impedance.
  • the pulse-echo principle is illustrated in FIG. 3A where a pulse of ultrasound reflects off of a blood-tissue boundary and partially returns to the HIU crystal. The amplitude of the reflection depends on the proximity and orientation of the HIU transducer and is maximized when the HIU crystal surface is touching and parallel to the tissue surface, as depicted in FIG. 3B.
  • the pulse-echo principle forms the basis for all medical ultrasound diagnostic imaging as well as the non-destructive ultrasound testing and many other techniques.
  • FIG. 3B depicts an example of an ultrasound ablation catheter which has an ideal orientation relative to tissue, in accordance with various embodiments.
  • the longitudinal axis 320 is parallel relative to the interface.
  • an anchor may optionally keep the catheter spaced apart from the interface so that the catheter does not touch the interface during ablation.
  • FIG. 3C depicts another example of an ultrasound ablation catheter which has an ideal orientation relative to tissue, in accordance with various embodiments.
  • the longitudinal axis 320 is parallel relative to the interface and the catheter is touching the tissue 315 at the interface 310.
  • the catheter may have a degree of freedom to rotate the side-facing transducer in order to optimize its orientation with respect to the tissue.
  • An anchor can optionally be used to keep the catheter on the tissue surface while allowing the catheter to spin freely along its length. The procedure of optimizing the catheter orientation is similar with this type of anchor design.
  • FIG. 3D depicts another example of an ultrasound ablation catheter which has an ideal orientation relative to tissue, in accordance with various embodiments, where the catheter includes an anchor 331 .
  • the catheter 330 includes portions 330a, 330b and 330c.
  • the portion 330c has a longitudinal axis 340 which is parallel to the interface 310. Additionally, the portion 330c of the catheter is spaced apart from the tissue by an anchor 331 .
  • a treatment region 310a of the tissue is also depicted.
  • the portion 330c includes the ablation transducer.
  • the catheter should be positioned and rotated such that its side-facing transducer is parallel to, and in direct contact with, the right ventricle (RV) endocardial surface of the interventricular septum (IVS).
  • RV right ventricle
  • IVS interventricular septum
  • the direction of transmission of the ultrasound signal should be perpendicular to the tissue interface.
  • the HIU catheter is first operated in a pulse-echo mode where the catheter rapidly emits a series of acoustic pressure pulses. These acoustic pressure pulses propagate to and reflect (echo) off the blood-tissue surface and back to the same same crystal where the acoustic pressure pulse originated.
  • the HIU crystal then operates in reverse, converting the acoustic pressure wave to an electrical signal.
  • the rapid succession of tissue reflection electrical signals is then processed and presented to the user at a rate that allows real-time acoustic feedback of catheter manipulation.
  • amplitude imaging which is also known as “A-mode” or “A-line imaging”.
  • FIG. 4A depicts a trace 400 of an amplitude of a pulse-echo waveform versus time for an ultrasound ablation catheter having the poor orientation of FIG. 3A, in accordance with various embodiments.
  • the trace 401 represent a background signal and a current echo signal which are essentially overlapping.
  • the trace 400 represents a signal processed from the trace 401 . It shows the result of, first, subtracting the current echo from the background, then calculating the envelope, and finally calculating the magnitude (absolute value).
  • the trace 400 has a peak 400a which is not distinct.
  • a “contact value” indicates a relative height of the peak.
  • a line denoted by “max” indicates the maximum of the trace 400.
  • FIG. 4B depicts a trace 450 of an amplitude of a pulse-echo waveform versus time for an ultrasound ablation catheter having the ideal orientation of FIG. 3B, in accordance with various embodiments.
  • the trace 451 represent a background signal and a current echo signal which are essentially overlapping.
  • the trace 450 represents a signal processed from the trace 451 .
  • the trace 450 has a peak 450a which is distinct, as indicated by the relatively high “contact value.”
  • a line denoted by “max” indicates the maximum of the trace 450. This shows a processed signal indicating an ideal orientation and proximity to tissue.
  • the traces of FIG. 4A and 4B are from oscilloscope screen captures of pulse-echo signals. Each trace represents a single echo, as it is sequentially processed from the original signal (trace 401 or 451) to the final version (trace 400 or 450, respectively).
  • FIG. 5 depicts a plot of a pulse-echo amplitude as a function of a degree of tissue contact, in accordance with various embodiments.
  • the data was obtained in an ex-vivo model, accounting for tissue perfusion. Under direct visualization in a degassed water bath, the catheter/transducer was maintained in three distinct positions with respect to the interface: a) zero contact, e.g., >10 mm away (data points 500), b) intermittent/bouncing (80 bpm or bounces per minute) (data points 510) and c) steady/parallel contact (data points 520).
  • the data demonstrates a clear increase in the pulse-echo amplitude with improved contact.
  • the data points are depicted by dots, while the standard deviation is shown by a vertical line and the mean is shown by a circle.
  • FIG. 6A depicts an example system 600 for operating an ultrasound ablation catheter in a pulse-echo mode or a therapy mode, in accordance with various embodiments.
  • the high-intensity ultrasound catheter 100 discussed previously is depicted as a block in the system.
  • the catheter can be controlled in the pulse-echo mode using a pulse-echo trigger waveform generator 605 and a pulser-receiver 610 in a pulse-echo subsystem 601 , or in the therapy mode using a therapy waveform generator 620 and a power amplifier 625 in a therapy subsystem 602.
  • a signal processing system and display oscilloscope 615 receives inputs from both the pulser-receiver and the power amplifier to provide a display such as depicted in FIG. 4A and 4B.
  • the feedback to the operator could be in another form as well such as an audio signal which indicates when the catheter is in an ideal orientation and position relative to the target tissue.
  • a switch connects the catheter 100 to either the pulse-echo subsystem 601 or the therapy subsystem 602 based on which mode is currently being used. The switch can be manually changed by the operator from the pulse-echo mode to the therapy mode in response to viewing the oscilloscope traces, in one approach.
  • FIG. 8A An example waveform of the pulse-echo trigger waveform generator 605 is depicted in FIG. 8A.
  • pulses are generated periodically while the operator positions the catheter to find an optimal position. Once the optimal position is found, the therapy mode is initiated.
  • the optimal position of the catheter with respect to the tissue is when a longitudinal axis of the catheter is parallel, e.g., within a threshold such as up to +/-5, 10 or 15 degrees, of a plane in which the surface of the tissue extends.
  • a waveform provided by the therapy waveform generator 620 is amplified by the power amplifier, and a corresponding amplified waveform is provided to the ultrasound transducer via a matching transformer.
  • the therapy waveform generator 620 and the pulse-echo trigger waveform generator 605 both emit waveforms at the same time, and the switch 630 is positioned to select one of the waveforms based on the current mode. This allows the system to alternate back and forth between the pulse-echo mode and the therapy mode if needed.
  • the system can be implemented using a connected system of commercially available electronics hardware.
  • the pulse-echo trigger waveform generator 605 and the therapy waveform generator 620 can be provided by separate instances of the Agilent Keysight 33220A, a 20 MHz synthesized function generator with built-in arbitrary waveform and pulse capabilities.
  • the pulser-receiver 610 can be provided by Olympus Panametrics 5077PR pulser-receiver, a square wave pulser-receiver unit.
  • the power amplifier 625 can be provided by Amplifier Research 600A225 RF amplifier.
  • the signal processing system and display oscilloscope 615 can be provided by the LeCroy WaveRunner 44 MXi-A.
  • the catheter sends ultrasonic waves toward the tissue and receives an echo in return, as indicated by the solid line wave fronts 630 and 631 , respectively.
  • the catheter sends ultrasonic waves toward the tissue without processing the echo, in one possible implementation, as indicated by the dashed line wave fronts 640.
  • the transmitted wave or pulse can be considered to be a transmit pulse and a received pulse can be considered to be an echo or reflected pulse.
  • the HIU catheter operates in either a pulse-echo mode or a therapy mode.
  • the HIU catheter crystal is designed for thermal therapy where the backing material is air. This minimizes damping and allows the transducer to ring as freely as possible at its resonance frequency.
  • imaging transducers are usually designed with a solid backing material to improve sensitivity. Distinguishing the reflected acoustic wave signal from noise present in an air- backed transducer is a primary challenge to realizing the technique.
  • the commercially available Olympus Panametrics 5077PR ultrasound pulser-receiver (PR) was chosen as the pulse-echo source for the early stages of implementation.
  • the PR design is relatively mature in non-destructive (NDT) testing. It offers the ability to change basic excitation waveform parameters and is designed to be used with NDT specific transducers. However, a significant opportunity exists to better tailor pulse-echo excitation waveforms to the HIU catheter.
  • the tissue-reflected signal is digitized by the oscilloscope and processed by a custom real-time algorithm implemented using Mathworks® MATLAB® software, for example.
  • the switch 630 in Fig. 6A can be manually or automatically operated. For example, it can be automatically changed to the therapy mode when the pulse-echo mode is completed and it is confirmed that the catheter is in the optimal position. Furthermore, one could theoretically monitor the therapy by interleaving pulse-echo with longer duration continuous wave to either monitor orientation/contact or lesion formation.
  • the operator may view the oscilloscope or a real-time chart read-out of the oscilloscope measurement, for example, to determine when the catheter is in the optimal position. It is also possible to automatically indicate when the optimal position is reached. For example, in a clinical device, custom user software can be provided in which it is feasible to synchronize an audio tone, for instance, with a simplified visual display of the measurement.
  • a PC-based oscilloscope may be used for greater system control capability.
  • the PC-based oscilloscope software can perform the same functions as a standalone oscilloscope and can present the pulse-echo data in an easier-to-read format.
  • FIG. 6B depicts an example data processing system consistent with FIG. 6A, in accordance with various embodiments.
  • the data processing system 650 can be used to control, or be incorporated, into one or more of the components 605, 610, 615, 620, 625 and 630 of FIG. 6A.
  • This system includes a processor 652 for executing instructions stored in a memory 653.
  • the memory 653 can be a computer-readable non-transitory storage medium such as a read only memory (ROM), a random access memory (RAM), a flash memory device, a hard disk drive, a magnetic storage media, or an optical storage medium.
  • the processor is to execute the instructions to perform the techniques described herein.
  • a display 651 can be used to provide an output, such as a reflection signal envelope, for use by an operator in guiding the catheter.
  • FIG. 7A depicts a flowchart of an example process for operation an ultrasound ablation catheter, in accordance with various embodiments.
  • Step 700 includes positioning the ultrasound ablation catheter in the body adjacent to the target tissue.
  • Step 701 includes transmitting a pulse toward the target tissue. This step can be performed by the pulse-echo subsystem 601 and the HIU catheter 100, for example.
  • Step 702 includes detecting the amplitude of the echo pulse. This step can be performed by the HIU catheter 100, the pulser-receiver 610 and the signal processing system and display oscilloscope 615, for example.
  • a decision step 703 determines whether the position is optimum. The operator can make this decision based on information displayed on the signal processing system and display oscilloscope 615, for example.
  • step 704 includes performing the ultrasound ablation therapy. This step can be performed by the therapy subsystem 602 and the HIU catheter 100, for example. Information can be provided to the operator, e.g., a doctor or other medical personnel, to indicate that it is appropriate to begin to perform the ultrasound ablation therapy. If the decision step is false (F), step 700 is repeated to reposition the ultrasound ablation catheter. The re-positioning could include moving the catheter lengthwise and/or rotating the catheter.
  • the ultrasound ablation therapy begins automatically once the position is optimum.
  • FIG. 7B depicts a flowchart of an implementation of the example process of FIG. 7A, in accordance with various embodiments.
  • the process can be performed for each thermal lesion which is to be formed.
  • the steps include: While pulsing the catheter and listening for echo reflections:
  • step 710 Switch the HIU driving electronics to pulse-echo mode, e.g., to use the pulseecho subsystem 601 , and orient the HIU catheter such that no acoustic reflectors are present (step 710). Record a “baseline” waveform (only necessary on 1st lesion) (step 711). This step can be performed by the signal processing system and display oscilloscope 615, for example.
  • step 713 Pulse the catheter (step 713). This step can be performed by the pulse-echo subsystem 601 , for example.
  • step 714 Acquire and digitize the reflected pulse (step 714). This step can be performed by the HIU catheter 100, the pulser-receiver 610 and the signal processing system and display oscilloscope 615, for example.
  • step 715 Subtract the reflected pulse from the baseline pulse (step 715). This step can be performed by the signal processing system and display oscilloscope 615, for example.
  • step 716 Apply a Hilbert transform and display the reflection signal envelope (step 716). This step can be performed by the signal processing system and display oscilloscope 615, for example.
  • step 717 Compute the magnitude of the difference (step 717). This step can be performed by the signal processing system and display oscilloscope 615, for example.
  • Switch HIU driving electronics e.g., using the switch 630, to perform thermal therapy in the thermal therapy mode (step 719).
  • the thermal therapy can be performed using the therapy subsystem 602 and the HIU catheter 100, for example.
  • FIG. 8A depicts waveforms used to generated a series of pulses of an ultrasound ablation catheter in a pulse-echo mode, in accordance with various embodiments.
  • the horizontal axis depicts time (t) and the vertical axis depicts voltage (V).
  • the waveforms can be provided by the pulse-echo trigger waveform generator 605 of FIG. 6A, for example.
  • the bursts can be repeated according to a pulse repetition period.
  • FIG. 8B depicts a pressure pulse generated by an ultrasound ablation catheter consistent with FIG. 8A, in addition to a corresponding echo pulse, in accordance with various embodiments.
  • the horizontal axis depicts time (t) and the vertical axis depicts pressure (P).
  • the pressure pulse 830 corresponds to the burst 800. Additionally, an echo pulse 831 is received sometime after the transmission of the pressure pulse.
  • the waveform generated by the therapy waveform generator 620 of FIG. 6A is a continuous, higher-power waveform such as 30- 120 sec.

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Abstract

L'invention concerne des techniques servant à faire fonctionner un cathéter d'ablation par ultrasons haute intensité avec un positionnement amélioré par rapport à un tissu cible. La position et l'orientation du cathéter peuvent être gérées par un opérateur sur la base d'un traitement de signal en temps réel et d'un affichage de l'onde réfléchie de surface tissulaire. Par maximisation de l'amplitude et minimisation du retard temporel de l'onde réfléchie par le tissu, le transducteur et la surface tissulaire sont alignés pour être parallèles. Le cathéter peut ensuite être actionné dans un mode de thérapie pour former une lésion, la lésion étant prédite pour être formée dans une direction perpendiculaire à la surface tissulaire en contact avec le cathéter.
PCT/US2023/012884 2022-02-18 2023-02-13 Ablation par ultrasons guidée par échos d'impulsion, procédé acoustique de détection d'orientation et de proximité des tissus d'un cathéter d'ablation par ultrasons Ceased WO2023158603A1 (fr)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6254542B1 (en) * 1995-07-17 2001-07-03 Intravascular Research Limited Ultrasonic visualization method and apparatus
US20090076390A1 (en) * 2005-11-23 2009-03-19 Warren Lee Integrated ultrasound imaging and ablation probe
US20120172871A1 (en) * 2010-12-30 2012-07-05 Roger Hastings Ultrasound guided tissue ablation
US20150359512A1 (en) * 2014-06-11 2015-12-17 The Johns Hopkins University Synthetic aperture ultrasound system

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6254542B1 (en) * 1995-07-17 2001-07-03 Intravascular Research Limited Ultrasonic visualization method and apparatus
US20090076390A1 (en) * 2005-11-23 2009-03-19 Warren Lee Integrated ultrasound imaging and ablation probe
US20120172871A1 (en) * 2010-12-30 2012-07-05 Roger Hastings Ultrasound guided tissue ablation
US20150359512A1 (en) * 2014-06-11 2015-12-17 The Johns Hopkins University Synthetic aperture ultrasound system

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
DUNCAN M. G.: "REAL-TIME ANALYTIC SIGNAL PROCESSOR FOR ULTRASONIC NONDESTRUCTIVE TESTING*.", PROCEEDINGS OF THE INSTRUMENTATION AND MEASUREMENT TECHNOLOGY CONFERENCE. SAN JOSE, FEB. 13 - 15, 1990., NEW YORK, IEEE., US, vol. 39, no. 6, 13 February 1990 (1990-02-13), US , pages 32 - 37, XP000163855 *

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