EP-4740869-A2 - SYSTEMS AND METHODS FOR PROVIDING TISSUE INFORMATION IN AN ANATOMIC TARGET REGION USING ACOUSTIC REFLECTORS

EP4740869A2EP 4740869 A2EP4740869 A2EP 4740869A2EP-4740869-A2

Abstract

Various approaches for computationally characterizing tissue in an anatomic target region include generating multiple sonications to transient acoustic reflectors at or proximate to the target region; measuring reflection signals of the sonications off the transient acoustic reflectors; based on the measurements, identifying the reflection signals originating from single transient acoustic reflectors; and based at least in part on the identified reflection signals, generating a digital map including a tissue characteristic.

Inventors

PRUS, OLEG
RINOTT, SHAHAR
LEVY, YOAV
SCHUSTER, ISRAEL

Assignees

Insightec Ltd.

Dates

Publication Date: 20260513
Application Date: 20201218

Claims (15)

A system for evaluating a treatment effect on a target region, the system comprising: an ultrasound transducer; and a controller configured to: (a) cause the transducer to generate a plurality of sonications to transient acoustic reflectors at or proximate to the target region in accordance with a sonication plan; (b) measure reflection signals of the sonications off at least some of the transient acoustic reflectors; and (c) based at least in part on the measured reflection signals, determine the treatment effect of the sonications on the target region.
The system of claim 1, wherein the controller is further configured to: determine at least one of a concentration or a flow rate of the transient acoustic reflectors in the blood vessel based at least in part on the measured reflection signals; and determine the treatment effect based at least in part on the determined concentration and/or flow rate.
The system of claim 2, wherein the controller is further configured to determine, based at least in part on an injection rate of the transient acoustic reflectors, the concentrations of the transient acoustic reflectors in a plurality of portions of blood vessels located in proximity to the target region.
The system of claim 3, wherein the controller is further configured to: determine an acoustic intensity distribution associated with at least one of the transient acoustic reflectors in at least one of the portions of the blood vessels based at least in part on the measured reflection signals; assign a weighting factor to each of a plurality of sub-regions within the at least one said blood vessel portion based on the acoustic intensity associated therewith; and determine the concentration of the transient acoustic reflectors in the at least one said blood vessel portion based at least in part on the weighted average of the acoustic intensities associated with the sub-regions.
The system of claim 2, wherein the controller is further configured to: cause the transducer to generate a second plurality of sonications to a sub-region within the target region so as to reduce a concentration of the transient acoustic reflectors therein; and determine the flow rate based at least in part on the measured reflection signals from the transient acoustic reflectors within the sub-region.
The system of claim 1, wherein the treatment effect comprises at least one of a tissue aberration or a temperature increase.
The system of claim 1, wherein the sonication plan is a treatment plan or a diagnosis plan.
The system of claim 1, further comprising an administration device for introducing the transient acoustic reflectors at or proximate to the target region.
A method of evaluating a treatment effect on a target region, the method comprising: (a) generating a plurality of sonications to transient acoustic reflectors at or proximate to the target region in accordance with a sonication plan; (b) measuring reflection signals of the sonications off at least some of the transient acoustic reflectors; (c) based at least in part on the measured reflection signals, determining the treatment effect of the sonications on the target region.
The method of claim 9, further comprising: determining at least one of a concentration or a flow rate of the transient acoustic reflectors in the blood vessel based at least in part on the measured reflection signals; and determining the treatment effect based at least in part on the determined concentration and/or flow rate.
The method of claim 10, further comprising determining, based at least in part on an injection rate of the transient acoustic reflectors, the concentrations of the transient acoustic reflectors in a plurality of portions of blood vessels located in proximity to the target region.
The method of claim 9, further comprising: determining an acoustic intensity distribution associated with at least one of the transient acoustic reflectors in at least one of the portions of the blood vessels based at least in part on the measured reflection signals; assigning a weighting factor to each of a plurality of sub-regions within the at least one said blood vessel portion based on the acoustic intensity associated therewith; and determining the concentration of the transient acoustic reflectors in the at least one said blood vessel portion based at least in part on the weighted average of the acoustic intensities associated with the sub-regions.
The method of claim 9, further comprising: causing the transducer to generate a second plurality of sonications to a sub-region within the target region so as to reduce a concentration of the transient acoustic reflectors therein; and determining the flow rate based at least in part on the measured reflection signals from the transient acoustic reflectors within the sub-region.
The method of claim 9, wherein the treatment effect comprises at least one of a tissue aberration or a temperature increase.
The method of claim 9, wherein the sonication plan is a treatment plan or a diagnosis plan.

Description

RELATED APPLICATION This application claims the benefit of and priority to U.S. Provisional Patent Application No. 62/949,597, filed on December 18, 2019, the entire disclosure of which is hereby incorporated by reference in its entirety. FIELD OF THE INVENTION The present invention relates, generally, to systems and methods for providing tissue information in an anatomic target region and, more particularly, to providing the tissue information using acoustic reflectors. BACKGROUND Tissue, such as a benign or malignant tumor or blood clot within a patient's skull or other body region, may be treated invasively by surgically removing the tissue or non-invasively by using, for example, thermal ablation. Both approaches may effectively treat certain localized conditions within the body, but involve delicate procedures to avoid destroying or damaging otherwise healthy tissue. Unless the healthy tissue can be spared or its destruction is unlikely to adversely affect physiological function, surgery may not be appropriate for conditions in which diseased tissue is integrated within healthy tissue. Ultrasound therapy, as may be accomplished using focused ultrasound, has particular appeal for treating diseased tissue surrounded by or neighboring healthy tissue or organs because the effects of ultrasound energy can be confined to a well-defined target region. Ultrasonic energy may be focused to a zone having a cross-section of only a few millimeters due to relatively short wavelengths (e.g., as small as 1.5 millimeters (mm) in cross-section at one MegaHertz (1 MHz)). Moreover, because acoustic energy generally penetrates well through soft tissues, intervening anatomy often does not pose an obstacle to defining a desired focal zone. Thus, ultrasonic energy may be focused at a small target in order to ablate diseased tissue without significantly damaging surrounding healthy tissue. In addition, ultrasound may be utilized to open the blood-brain barrier (BBB) in the treatment of neurological diseases. The BBB, formed by layers of cells in the central nervous system (CNS), prevents large molecules from entering the brain parenchyma, and thus presents one of the largest obstacles to treating many brain diseases. Specifically, the BBB prevents many therapeutic agents, such as drugs and gene-therapy vectors, from reaching a patient's brain tissue. For example, treatments for CNS infections, neurodegenerative diseases, congenital enzyme defects and brain cancer are all hampered by the ability of the BBB to block passage of, inter alia, antibiotics, anti-retroviral drugs, enzyme replacement therapy, gene preparations and anti-neoplastic drugs. It is thus desirable to using ultrasound energy to temporarily and locally "open" the BBB to permit therapeutic quantities of these agents to access the affected brain tissue. An ultrasound focusing system generally utilizes an acoustic transducer surface, or an array of transducer surfaces, to generate an ultrasound beam. The transducer may be geometrically shaped and positioned to focus the ultrasonic energy at a "focal zone" corresponding to the target tissue mass within the patient. During wave propagation through the tissue, a portion of the ultrasound energy is absorbed, leading to increased temperature and, eventually, to cellular necrosis - preferably at the target tissue mass in the focal zone. The individual surfaces, or "elements," of the transducer array are typically individually controllable, i.e., their phases and/or amplitudes can be set independently of one another (e.g., using a "beamformer" with suitable delay or phase shift in the case of continuous waves and amplifier circuitry for the elements), allowing the beam to be steered in a desired direction and focused at a desired distance, and the focal zone properties to be shaped as needed. Thus, the focal zone can be rapidly displaced and/or reshaped by independently adjusting the amplitudes and/or phases of the electrical signal input into the transducer elements. During a focused ultrasound procedure, system parameters are generally fixed for a given transducer array, but tissue homogeneity may vary significantly from patient to patient, and even between different tissue regions within the same patient and organ. Tissue inhomogeneity may decrease the intensity of the acoustic energy reaching the focal zone and may even move the location of the focal zone within the patient's body. In addition, different types of tissue may respond differently to the ultrasound application. For example, although exposing tissue to ultrasound may generally increase its permeability, different types of tissue may have different permeability responses. In addition, different types of tissue may have different degrees of viability in response to application of ultrasound. Accordingly, to effectively and efficiently treat the target tissue while avoiding damage to non-target tissue, a need exists to acquire information about target and/or