Ultrasonic processing apparatus comprising means for imaging cavitation bubbles
Inventors
Pernot, Mathieu • Suarez, Daniel
Assignees
Cardiawave SA • Centre National de la Recherche Scientifique CNRS • Institut National de la Sante et de la Recherche Medicale INSERM • Ecole Superieure de Physique et Chimie Industrielles de Ville de Paris ESPCI
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Publication Number
US-11571230-B2
Publication Date
2023-02-07
Expiration Date
Abstract
An ultrasonic processing apparatus is provided. The ultrasonic processing apparatus comprises an ultrasonic therapy transducer (ATA) adapted to generate focused ultrasonic waves; an ultrasonic imaging transducer (UID) connected to the ultrasonic therapy transducer; and an electronic system configured to control the ultrasonic therapy transducer so as to emit a pulse train of ultrasonic waves generating a cloud of cavitation bubbles (BC); control the ultrasonic imaging transducer so as to acquire at least one image of the region to be processed; acquire a plurality of echo signals of ultrasonic wave pulses emitted by the ultrasonic therapy transducer captured by the ultrasonic imaging transducer; process the plurality of echo signals so as to reconstruct an image of the cloud of cavitation bubbles; and display said image of the cloud of cavitation bubbles superposed on said image of the region to be processed. The processing includes spatio-temporal filtering.
Core Innovation
The invention provides an apparatus for providing treatment with ultrasound using a therapy ultrasound transducer configured for generating focused ultrasonic waves. The therapy ultrasound transducer is controlled to emit a pulse train of ultrasonic-wave energy with a duration suitable for causing generation of a cloud of cavitation bubbles in a focal spot when the focal spot is positioned inside a region to be treated of a human or animal body. An imaging ultrasound transducer distinct from but associated with the therapy ultrasound transducer is controlled to emit ultrasonic waves between two therapy pulses and to acquire echoes for image reconstruction.
The apparatus acquires a plurality of echo signals of N>1 ultrasonic-wave pulses emitted by the therapy ultrasound transducer, with the signals captured by the imaging ultrasound transducer. The electronic system processes the echoes using a beamforming algorithm to form respective echo images, and uses spatio-temporal filtering that extracts components representative of backscatter from the cavitation bubbles while separating components representative of backscatter from tissues. The spatio-temporally filtered results reconstruct an image of the cloud of cavitation bubbles.
The reconstructed cavitation-bubble image is displayed superposed on an image of the region to be treated. During reconstruction, processing introduces compensation for a difference between the propagation time of ultrasonic waves from the therapy ultrasound transducer and the focal spot, and the propagation time from the focal spot to the imaging ultrasound transducer. The approach supports robustness to tissue motion by basing bubble-cloud imaging on passive echo acquisitions between therapy pulses.
Claims Coverage
Two independent claims are identified, one apparatus and one method, centered on an integrated therapy-and-passive-imaging ultrasound system with beamforming and spatio-temporal filtering to reconstruct and display an image of a cloud of cavitation bubbles. The claims include six inventive features covering synchronized acquisition between therapy pulses, separation of cavitation-bubble backscatter from tissue backscatter, and propagation-time compensation.
Therapy pulse train to generate cavitation bubble cloud at focal spot
A therapy ultrasound transducer configured for generating focused ultrasonic waves, controlled to emit a pulse train of ultrasonic waves of energy with a duration suitable for causing generation of a cloud of cavitation bubbles in a focal spot inside a region to be treated of a human or animal body.
Distinct associated imaging transducer acquiring echoes between therapy pulses
An imaging ultrasound transducer distinct from but associated with the therapy ultrasound transducer, controlled to emit ultrasonic waves directed toward the region to be treated between two ultrasonic-wave pulses emitted by the therapy ultrasound transducer to acquire echoes and process echoes to reconstruct at least one image of the region to be treated.
Multi-pulse passive echo acquisition and beamforming
Acquiring a plurality of echo signals of N>1 ultrasonic-wave pulses emitted by the therapy ultrasound transducer, processed using a beamforming algorithm to form respective echo images.
Spatio-temporal filtering to extract cavitation-bubble backscatter
Using spatio-temporal filtering allowing components representative of backscatter from the cavitation bubbles to be extracted and separated from components representative of backscatter from tissues of the region to be treated, so as to reconstruct an image of the cloud of cavitation bubbles.
Superposed display of cavitation cloud image on tissue image
Displaying, superposed on the image of the region to be treated, the image of the cloud of cavitation bubbles.
Propagation-time compensation during cavitation cloud reconstruction
Introducing a compensation for a difference between the propagation time from the therapy ultrasound transducer to the focal spot, and the propagation time from the focal spot to the imaging ultrasound transducer during reconstruction of the cavitation-bubble image.
Overall, the independent claims require a distinct associated imaging ultrasound transducer that acquires passive echoes between therapy pulses, with N>1 pulse beamforming and spatio-temporal filtering to isolate cavitation-bubble backscatter from tissue backscatter to reconstruct and display a cavitation-bubble-cloud image, including propagation-time compensation to address timing differences.
Stated Advantages
Improved bubble-cloud imaging contrast-to-noise ratio versus active methods under moving conditions.
Documented Applications
Ultrasound treatment of a human or animal body in which a cloud of cavitation bubbles is generated at a focal spot and imaged, including in contexts with moving organs (e.g., heart, liver, kidneys).
Ultrasound treatment using HIFU, histotripsy, lithotripsy, and thrombotripsy with passive cavitation-bubble imaging superposed on an image of the region to be treated.
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