# US 2017/0281983 A1 · System for the ablation or the monitoring of a zone of the heart by ultrasounds and associated methods

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- Number: US 2017/0281983 A1
- Document ID: US20170281983A1
- Status: Published application
- Kind: A1
- Application number: 15/508,193
- Filed: 2015-09-01
- Published: 2017-10-05
- Earliest claimed: 2014-09-02
- Assignees: Institut National de la Sante et de la Recherche Medicale
- Applicants: Universite De Bordeaux; Institut National De La Sante Et De La Recherche Medicale; Centre Hospitalier Universitaire De Bordeaux
- Inventors: Fabrice MARQUET; Pierre BOUR; Bruno QUESSON; Fanny VAILLANT
- Web page: https://patentgrep.com/patent/US20170281983A1

## CPC

- A61N 7/02: Localised ultrasound hyperthermia
- A61B 5/0036: {including treatment, e.g., using an implantable medical device, ablating, ventilating}
- A61B 5/055: involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
- A61B 5/33: specially adapted for cooperation with other devices
- A61B 5/7285: {for synchronizing or triggering a physiological measurement or image acquisition with a physiological event or waveform, e.g. an ECG signal}
- A61B 8/085: {for locating body or organic structures, e.g. tumours, calculi, blood vessels, nodules}
- A61B 8/0883: {for diagnosis of the heart}
- A61B 8/543: {involving acquisition triggered by a physiological signal}
- A61B 34/10: Computer-aided planning, simulation or modelling of surgical operations
- A61B 90/37: {Surgical systems with images on a monitor during operation}
- A61B 6/503: {for diagnosis of the heart}
- A61B 6/541: {involving acquisition triggered by a physiological signal}
- A61B 2017/00044: {Sensing electrocardiography, i.e. ECG}
- A61B 2018/00351: {Heart}
- A61B 2018/00648: {using more than one sensed parameter}
- A61B 2018/00702: {Power or energy}
- A61B 2018/00779: {Power or energy}
- A61B 2018/00791: {Temperature}
- A61B 2018/00839: {Bioelectrical parameters, e.g. ECG, EEG}
- A61B 2034/105: {Modelling of the patient, e.g. for ligaments or bones}
- A61B 2034/107: {Visualisation of planned trajectories or target regions}
- A61B 2090/374: {NMR or MRI}
- A61B 2090/3762: {using computed tomography systems [CT]}
- A61B 2090/378: {using ultrasound}
- A61N 2007/0095: {by modifying an excitation signal}
- A61N: ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY (measurement of bioelectric currents A61B; surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body A61B18/00; anaesthetic apparatus in general A61M; incandescent lamps H01K; infrared radiators for heating H05B)
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)

## Abstract

A system for ablating or monitoring a zone of the heart, includes a system to measure the heart electrical activity; a phased array for generating a beam of focussed ultrasound signals on a targeted zone of the heart; an imaging system determining an image of a transcostal wall projected in an image plane of the phased array by taking into consideration a position and direction of the phased array and making it possible to deactivate elements of the phased array in accordance with the position of the elements with regard to the position of the projected image of the transcostal wall; a positioning system to control the position of a focussed zone of a beam of focussed ultrasound signals on the targeted zone, a monitoring system to measure a temperature and tissue deformation in the targeted zone; and a device for measuring a level of cavitation in the targeted zone.

## Claims

### Claim 1

A method for calibrating a focussed signal for its application in a zone of a heart, the method comprising:
acquiring at least one frequency of an electrocardiogramof the heart;
acquiring at least one image of a region of the heart in which a targeted zone is located, said at least one image being acquired in synchronisation with the frequency acquired from the electrocardiogram of the heart by an imaging system;
generating a first beam of focussed ultrasound signals in the targeted zone, said first beam being emitted by a phased array, said ultrasound signals being configured in phase to generate at least one pulse in a focussed zone, said at least one pulse being synchronised with the frequency acquired from the electrocardiogram of the heart, the pulse having a predefined amplitude and duration;
performing a dynamic control of a position of the focussed zone on a position of the targeted zone by a positioning system so as to measure displacements linked to respiratory movements of the heart in a reference frame linked to the phased array and to deduce therefrom a compensation parameter to calculate a new position of the targeted zone, said phased array automatically applying a phase parameter to each signal to deflect the first beam to the new position of the targeted zone; and
determining a temperature at the a level of the focussed zone from an acquisition of at least one image of said zone by an imaging system, the amplitude and/or the duration of the pulse being configured such that the measured temperature does not exceed a temperature set point.

### Claim 2 (depends on 1)

The method according to claim 1, further comprising:
determining a tissue deformation in the focussed zone in response to at least one pulse of the first beam.

### Claim 3 (depends on 1)

The method according to claim 1, further comprising:
determining by an imaging system an image of a transcostal wall projected in an image plane of the phased array by taking into consideration a position and a direction of the phased array;
a deactivation of elements of the phased array in accordance with the position of said elements with regard to a position of the projected image of the transcostal wall.

### Claim 4 (depends on 1)

The method according to claim 1, further comprising:
performing a dynamic control of the deactivation and the activation of elements of the phased array as a function of a calculation of each phase parameter applied to each of the signals.

### Claim 5 (depends on 1)

The method according to claim 1, wherein the temperature in the focussed zone and a tissue deformation are determined by a single imaging system, said imaging system being an MRI imaging system, wherein data acquired by the MRI imaging system are utilized to deduce a local tissue deformation induced by the ultrasound pressure generated by the first beam of ultrasound signals and a local rise in temperature induced by an energy generated locally by the beam of ultrasound signals.

### Claim 6 (depends on 1)

The method according to claim 1, wherein a comparison of the position of the focussed zone determined by an imaging system and the position of the targeted zone determined by the positioning system, generates at least one data for calibrating elements of the phased array so as to make a position of the focussed zone correspond with the position of the targeted zone.

### Claim 7 (depends on 1)

The method according to claim 1, wherein the positioning system is:
either an MRI imaging system, the positions being calculated from image processing;
or from a positioning system comprising at least one emitter emitting ultrasound waves and a plurality of ultrasounds sensors detecting he reflected waves, the position being determined by triangulation.

### Claim 8 (depends on 1)

The method according to claim 1, further comprising calibrating a signal generated in the focussed zone by defining parameters comprising at least one level of the amplitude and a pulse duration as a function of at least one data among which:
a temperature set point in the focussed zone and/or in neighbouring zones and/or in the ribs of the transcostal wall;
a tissue deformation set point in the focussed zone, and/or;
a level of cavitation set point in the focussed zone, and/or;
a detection of movement of the focussed zone in a reference point linked to the phased array, and/or;
an electrical activity set point in the focussed zone.

### Claim 9 (depends on 1)

The method according to claim 1, wherein the steps of the monitoring method are carried out in different targeted zones of the heart, the method further comprising, after the application of a beam of focussed signals:
verifying different values representing either tissue deformations of each targeted zone (ZC), or electrical levels measured near to or in each targeted zone, said measured values being compared to given thresholds.

### Claim 10

A method for ablating a zone of a heart by generation of a beam of focussed ultrasound signals, the method comprising:
acquiring at least one frequency of an electrocardiogram of the heart;
determining at least one position of a targeted zone in the heart;
generating a beam of focussed ultrasound signals in the targeted zone of which:
an amplitude is continuous and is comprised in the range of values [1-100 MPa];
a duration of application of the focussed beam being applied over a period above 1 ms;
controlling a position of the focussed zone of the beam on the position of the targeted zone calculated in real time by a positioning system;
performing an active monitoring in real time of a temperature in the focussed zone or a zone neighbouring the focussed zone from an acquisition of image(s).

### Claim 11 (depends on 10)

The ablation method according to claim 10, wherein the duration of application of the focussed beam comprises at least one micro-interruption (MC) of a duration longer than 1 ms during which the step of active monitoring comprises at least one measurement of an elasticity of a tissue of the targeted zones.

### Claim 12 (depends on 11)

The ablation method according to claim 11, wherein the active monitoring comprises a measurement of a level of cavitation of the focussed zone by an ultrasound sensor detecting a spectrum of ultrasound frequencies in or near to the focussed zone, a level of cavitation being deduced from a spectral noise level.

### Claim 13 (depends on 10)

The ablation method according to claim 10, wherein the active monitoring comprises a measurement of an elasticity of a tissue deduced from a measurement of a relaxation time of the tissue:
either from an image of an MRI imaging system;
or from an image of an ultrasound imaging system by an elastometry measurement.

### Claim 14 (depends on 12)

The ablation method according to claim 12, wherein a measurement of an elasticity of a tissue of the targeted zone and/or the measurement of the level of cavitation automatically determines a data corresponding to the duration of the focussed beam to apply after the micro-interruption and/or to determine the time at which a next micro-interruption will be generated.

### Claim 15 (depends on 10)

The ablation method according to claim 10, further comprising performing a dynamic control of a position of the focussed zone on the position of the targeted zone by a positioning system, the dynamic control comprising a measurement of displacements linked to a respiratory movement of the heart in a reference frame linked to a phased array and deducing therefrom a first compensation parameter to calculate a new position of the targeted zone, said phased array automatically applying a phase parameter to each signal to deflect the beam to thea new position of the focussed zone.

### Claim 16 (depends on 10)

The ablation method according to claim 10, further comprising performing a dynamic control of the position of the focussed zone on the position of the targeted zone by positioning system so as to measure contraction movements of the heart during an occurrence of a QRS complex in a reference frame linked to the phased array and to deduce therefrom a second compensation parameter to calculate a new position of the targeted zone, said phased array automatically applying a phase parameter to each signal to deflect the beam to a new position of the focussed zone.

### Claim 17 (depends on 10)

The ablation method according to claim 10, further comprising:
determining by an imaging system an image of a transcostal wall projected in an image plane of a phased array by taking into consideration a position and a direction of the phased array;
deactivating elements of the phased array when signals emitted from said elements are capable of intercepting the projected image of the transcostal wall.

### Claim 18 (depends on 17)

The ablation method according to claim 17, wherein the active monitoring comprises:
a dynamic control of the deactivation and an activation of the elements of the phased array in accordance with a position of the projected image of the transcostal wall on the elements of the phased array.

### Claim 19 (depends on 10)

The ablation method according to claim 10, wherein a second active monitoring of zones neighbouring the focussed zone is carried out, said second active monitoring including a measurement of the following parameters in real time:
a temperature of at least one zone neighbouring the focussed zone;
a tissue deformation in at least one zone neighbouring the focussed zone in response to at least one pulse of the first focussed beam, and/or;
a level of cavitation in at least one zone neighbouring the focussed zone in response to at least one pulse of the first focussed beam.

### Claim 20

A system for the ablation or the monitoring of a zone of a heart by ultrasounds comprising:
a measuring system configured to measure an electrical activity of the heart to acquire an electrocardiogram;
a phased array configured to generate a beam of focussed ultrasound signals focussed on at least one targeted zone of the heart;
an imaging system configured to determine an image of a transcostal wall projected in an image plane of the phased array by taking into consideration a position and a direction of the phased array and making it possible to deactivate elements of the phased array in accordance with a position of said elements with regard to a position of the projected image of the transcostal wall;
a positioning system coupled to the phased array in such a way as to control a position of at least one focussed zone of at least one beam of focussed ultrasound signals on a position of the at least one targeted zone;
a monitoring system configured to measure a temperature and a tissue deformation in the targeted zone;
a device configured to measure a level of cavitation in the targeted zone.

### Claim 21 (depends on 1)

A system for the ablation or the monitoring of a zone of a heart by ultrasounds comprising:
a measuring system configured to measure an the electrical activity of the heart to acquire an electrocardiogram;
a phased array configured to generate a beam of focussed ultrasound signals focussed on at least one targeted zone of the heart;
a positioning system coupled to the phased array in such a way as to control a position of at least one focussed zone of at least one beam of focussed ultrasound signals on a position of the at least one targeted zone;
a monitoring system configured to measure a temperature and a tissue deformation in the targeted zone;
a device configured to measure a level of cavitation in the targeted zone, wherein the system is configured to implement the steps of the method of claim 1.