Sunnybrook Research Institute

The Brigham and Women's Hospital, Inc.

Other

Sunnybrook Health Sciences Centre

Vitreosonic Inc.

Kullervo Henrik Hynynen

Meaghan Anne O'Reilly

Alec Hughes

Lulu Deng

Mark T Buchanan

Junho Song

Gregory T Clement

Ferenc A Jolesz

Rajiv Chopra

Nathan J McDannold

Anthony Chau

Erin Hutchinson

Meaghan O'reilly

Dov Maor

Sonya Shortkroff

Foroohar Foroozan

Elisa Konofagou

Ryan Jones

Javier Grinfeld

Douglas R Daum

Todd Fjield

Karoly Foldes

Carl Winalski

Gary Lloyd Ka Tao Yau

Adam Christian Waspe

Benjamin Lucht

Samuel Gunaseelan

David Goertz

Alex Wright

Meaghan Anne O'REILLY

Systems, methods and devices are provided for performing diagnostic or therapeutic transcranial procedures using a patient-specific transcranial headset. The patient-specific headset may include a patient-specific frame that is fabricated, according to volumetric image data, to conform to an anatomical curvature of a portion of a patient's head. The patient-specific frame is configured to support a plurality of transducers in pre-selected positions and orientations, which may be spatially registered to the volumetric image data. This spatial registration may be employed to control at least a portion of the transducers to focus energy at a preselected tissue region.

Patient-specific headset for diagnostic and therapeutic transcranial procedures

At ultrasound intensities below the cavitation threshold of the vitreous and blood cells (e.g., between 0.1 watts per square centimeter (W/cm) and 3.5 W/cm), relative hyperthermia can induce temperature elevations that result in hemolysis as well as liquefy vitreous, both of which can accelerate clearance. At high intensities (i.e., >800 W/cm2), with temperatures reaching >100 deg C., the target region may be vaporized. At intensities above the cavitation intensities short ultrasound bursts can result in mechanical fragmentation of the clot. In at least some examples, the present systems, devices and methods will allow for all of these modes of therapies.

Ultrasonic treatment of vitreous opacities

Various example embodiments of the present disclosure provide systems and methods for the dynamic correction and reduction of thermal variations in skull-induced aberrations during a focused ultrasound therapy procedure. Unlike conventional approaches involving static corrections for skull-induced aberrations, various example embodiments of the present disclosure employ ultrasound detection and a skull thickness estimate from volumetric image data to intermittently and dynamically determine corrections for skull-induced aberrations, such that aberration correction reduction is updated intraoperatively and maintained despite local thermally-induced changes in the speed of sound of the local skull region due to intraoperative intracranial heating. Furthermore, in some example embodiments, a measure dependent on the speed of sound with the skull is intraoperatively determined and compared to a previously determined value of the measure to determine a change in the skull temperature, based on a pre-determined relationship between changes in the measure and changes in skull temperature.

Systems and methods for reducing thermal skull-induced aberrations during transcranial ultrasound therapeutic procedures

Systems and methods are provided for performing transcranial diagnostic procedures using a transcranial ultrasound transducer array. The array elements are positioned and oriented such that far field regions respectively associated therewith spatially overlap within the brain of a patient. The array elements may be oriented approximately normal to the skull, permitting efficient coupling of ultrasound energy into the brain. The array elements are controlled to generate ultrasound pulses, where the timing of the pulses is controlled, based on registration between the array elements and volumetric image data, such that ultrasound energy is focused at a target within spatially overlapping far fields of the array elements. The transcranial ultrasound transducer array elements may be positioned and oriented relative to the skull such that their respective ultrasound beams are focused within the skull and diverging with the brain.

Systems and methods for performing transcranial ultrasound therapeutic and imaging procedures

A system and method for controlling the delivery of ultrasound energy to a subject is provided. In particular, such a system and method are capable of safely disrupting the blood-brain barrier. Ultrasound energy is delivered to produce cavitation of an ultrasound contrast agent at a selected pressure value. An acoustic signal is acquired following cavitation, from which a signal spectrum is produced. The signal spectrum is analyzed for the presence of harmonics, such as subharmonics or ultraharmonics. When subharmonics or ultraharmonics are present, the pressure value is decreased for subsequent sonications. If a previous sonication resulted in no subharmonics or ultraharmonics being generated, then the pressure value may be increased. In this manner, the blood-brain barrier can be advantageously disrupted while mitigating potentially injurious effects of the sonication.

System and method for controlling focused ultrasound treatment

A system and method is provided for generating ultrasound at the tip of an intravascular catheter. This may be used for the treatment of vascular occlusions, including chronic total occlusions (CTOs) and thrombotic occlusions (e.g., deep vein thrombosis, stroke, myocardial infarction). For instance, the systems and methods may be used to induce cavitation to enhance the enzymatic degradation of a vascular occlusion. In some configurations, the approach employs a hollow cylindrical transducer, electrically stimulated in the radial direction at a frequency corresponding to the length mode excitation, thereby projecting ultrasound forwards past the catheter tip. This design overcomes electrical impedance issues for the generation of low frequencies with a smaller diameter transducer capable of negotiating a coronary artery. The hole within the transducer may accommodate a guidewire to facilitate its placement adjacent to the proximal portion of the occlusion.

Systems and methods for treating vascular occlusions with catheter based ultrasound

Ultrasound devices and systems are disclosed in which cooling of an active acoustic element of an ultrasound transducer is achieved via an electrically conductive member that extends beyond a proximal side of the active acoustic element to contact a heat exchanger. The electrically conductive member delivers electrical driving signals to the active acoustic element while conducting heat to the heat exchanger. A region of the proximal surface of the active acoustic element that is free from contact with the electrically conductive member may also absent from contact with a liquid or a solid, thereby facilitating reflection of ultrasound energy. The heat exchanger may include an electrically insulating fluid that contacts the electrically conductive member to remove the heat conducted through the electrically conductive member. The active acoustic element may be a multilayer lateral mode element, and the electrically conductive member may form an electrode of the lateral mode element.

Systems and methods for cooling ultrasound transducers and ultrasound transducer arrays

Systems, methods and devices are provided for performing diagnostic or therapeutic transcranial procedures using a patient-specific transcranial headset. The patient-specific headset may include a patient-specific frame that is fabricated, according to volumetric image data, to conform to an anatomical curvature of a portion of a patient's head. The patient-specific frame is configured to support a plurality of transducers in pre-selected positions and orientations, which may be spatially registered to the volumetric image data. This spatial registration may be employed to control at least a portion of the transducers to focus energy at a pre-selected tissue region.

An ultrasound phased array transducer is disclosed that achieves suppression of grating lobes through the incorporation of a coupling layer, where the coupling layer is positioned adjacent to the phased array transducer such that an ultrasound beam propagates through the coupling layer prior to encountering a propagation medium. The phased-array elements may be provided such that one or both of the array pitch and a lateral extent of each ultrasound transducer element is larger than half of the ultrasound wavelength in the propagation medium. Grating lobes within the coupling layer and the propagation medium may be reduced or suppressed by selecting a coupling material having a speed of sound that exceeds that of the propagation medium. The coupling layer may have a thickness sufficient for the generation of a wavefront, and the coupling layer may be formed from a viscous or viscoelastic material.

Phased array transducer with coupling layer for suppression of grating lobes

A system and method for efficiently transmitting and receiving focused ultrasound through a medium, such as bone, is provided. The focal region of the focused ultrasound is iteratively updated to provide an improved focus through the medium. This method may be carried out using a transducer assembly that includes two or more transmit arrays each operating at a different frequency. An initial focus is set and updated by delivering focused ultrasound with a lower frequency transmit array. The phase corrections determined in the first iteration are applied to subsequently higher frequency transmit arrays and received signals, and the process repeated until a desired focus or image resolution is achieved.

System and method for measuring and correcting ultrasound phase distortions induced by aberrating media

Apparatus and method for delivering increased amounts of energy to localized treatment zones in a target tissue volume are provided. In some instances the non-linear wave propagation and other properties of the treatment apparatus and propagation medium as well as novel beam forming and control of the treatment apparatus are employed to generate extended focal zones for efficient treatment of a condition in a patient.

Thermal therapy apparatus and method using focused ultrasonic sound fields

Growing community of inventors

Toronto, Canada

Kullervo Henrik Hynynen