Systems and methods for component separation in medical imaging

A medical imaging system, comprising:

• at least one light source for delivering light energy to a volume of tissue;
• a transducer array for receiving a resulting acoustic signal;
• a processing subsystem for processing the acoustic signal to identify a secondary acoustic return component of the acoustic signal, and to determine at least a portion of a boundary of a region of the tissue using the secondary acoustic return component of the acoustic signal;
• and,
• an output device for presenting information about at least one of a direct acoustic return component and the secondary acoustic return component.

A system, comprising:

• a light source adapted to produce light at a first predominant wavelength and at a second predominant wavelength;
• a light path adapted to deliver the light from the light source toward an exit port, the exit port positioned to permit the delivery of light to a volume containing acoustic scatterers;
• a surface adapted to be acoustically coupled to the volume, the surface comprising a first feature and a second feature, wherein the first feature produces a wavefront that is stronger in response to light at the first predominant wavelength than the wavefront the first feature produces in response to light at the second predominant wavelength, and the second feature produces a wavefront in response to light at the second predominant wavelength that is at least as strong as the wavefront the second feature produces in response to light at the first predominant wavelength;
• an array of acoustic receivers that receive acoustic signals produced in response to light from the light source, wherein the acoustic signals received in response to the first predominant wavelength comprise a direct acoustic return from the volume and a secondary acoustic return from scattered wavefronts produced, at least in part, by the first feature and the second feature, and wherein the acoustic signals received in response to the second predominant wavelength comprise a direct acoustic return from the volume and a secondary acoustic return from scattered wavefronts produced, at least in part, by the first feature and the second feature;
• a processing subsystem configured to perform steps comprising:
• computing a spatial representation of a volume from the acoustic signals received in response to the first predominant wavelength and the acoustic signals received in response to the second predominant wavelength, the spatial representation reflecting a chromophore distribution in the volume, wherein the secondary acoustic return for the first predominant wavelength and the secondary acoustic return for the second predominant wavelength contribute to a distortion in the spatial representation, the contribution to the distortion for the first predominant wavelength has a distinguishable difference from the contribution to the distortion for the second predominant wavelength;
• and,
• mitigating the secondary acoustic return at the first predominant wavelength and the secondary acoustic return at the second predominant wavelength to substantially prevent the distortion in the spatial representation from appearing in a produced output image, wherein the output image is based on the spatial representation, and the output image comprises regions indicating the presence of the chromophore.

An opto-acoustic probe having a distal end, the probe comprising:

• a light path adapted to direct light from a light input toward the distal end of the probe;
• a light exit port at the distal end of the probe for the light to be directed into a volume to produce direct acoustic return signals;
• an ultrasound receiver to receive acoustic signals;
• an optically reflective portion on an outer surface;
• and,
• at least one opto-acoustic target on the outer surface, the opto-acoustic target adapted to generate acoustic wavefronts in response to the light, which acoustic wavefronts upon scattering within the volume produce scattered acoustic waves that can be detected by the ultrasound receiver and identified as secondary acoustic return when processed by a processing subsystem.

A system, comprising:

• an energy source configured to deliver electromagnetic energy to a volume comprising one or more acoustic targets;
• a probe with an outer surface to form a coupling interface between itself and a surface of the volume;
• one or more elements on the outer surface of the probe to produce a predictable wavefront pattern originating substantially at the coupling interface as a result of the delivered energy;
• and,
• an acoustic receiver to receive an acoustic return comprising direct acoustic return signals and secondary acoustic return signals, the secondary acoustic return signals comprising at least a portion of the predictable wavefront pattern that is scattered by the one or more acoustic targets;
• and,
• a processing subsystem that uses a received wavefront resulting from the predictable wavefront pattern in connection with producing an output.

An opto-acoustic probe, comprising:

• a transducer assembly;
• a light path to transmit energy from a light input towards a distal end of the probe;
• an exit port for the light to exit the distal end of the probe;
• an isolator to reduce the amount of energy transmitted from the light path to the transducer assembly, wherein an outer surface at the distal end of the probe comprises a surface of the isolator and the surface of the isolator comprises at least a portion having an optically reflective coating and the outer surface comprises a portion that is substantially less optically reflective than the optically reflective coating.

A sensor to interrogate a volume, the sensor comprising:

• acoustic receiver;
• photon exit port through which photons pass as they are delivered into the volume;
• photon absorbing element positioned a distance away from the exit port configured to absorb photons that have traveled through the volume;
• wave propagation medium external to the volume and proximate to the photon absorbing element and the acoustic receiver to permit an acoustic wave produced by the photon absorbing element to propagate from the photon absorbing element to the acoustic receiver;
• and,
• electrical path for connecting the acoustic receiver to be sampled by an acquisition system.

A system, comprising:

• a source of electromagnetic energy configured to produce more than one energy events in an acquisition frame, the energy events occurring at different times, each energy event comprising electromagnetic energy to be delivered to a volume;
• at least one acoustic receiver configured to receive acoustic signals from the volume;
• a data acquisition unit adapted to sample the at least one acoustic receiver during a period of time following a triggering event to record the acquisition frame, wherein the acquisition frame comprises multiple components, the multiple components comprising interfering direct acoustic return signals resulting from the more than one energy events, wherein a first of the interfering direct acoustic return signals of a first of the more than one energy events contributes to interference in the acquisition frame with at least one other of the interfering direct acoustic return signals of at least one other of the more than one energy events;
• a data processing subsystem comprising a component separation module configured to separate the interfering direct acoustic return signals;
• and,
• a display device for displaying data derived from at least one of the separated multiple components.

A method, comprising:

• depositing light energy directed through an exit port of a light path into an optically scattering volume, where a portion of the light energy that exits the exit port of the light path follows a sequence comprising entering the volume, scattering within the volume and exiting the volume;
• receiving acoustic signals originating from targets positioned proximate to a surface of the volume, wherein the targets absorb at least a portion of the portion of the light energy that has followed the sequence to exit the volume;
• analyzing the received acoustic signals to determine an intensity of the absorbed at least a portion of the portion of the light that has followed the sequence;
• and,
• determining at least one optical parameter of the volume based on the analyzed received acoustic signals.

A method, comprising:

• placing a surface of a probe proximate to a surface of a volume;
• delivering light from a light source to the volume, wherein a portion of the light from the light source is absorbed by patterns on the surface of the probe;
• receiving acoustic signals from the volume, wherein the received acoustic signals comprise components of acoustic signal resulting from scattering of wavefronts produced by the patterns on the surface of the probe in response to absorbing the portion of the light;
• processing the received acoustic signals to identify a component that resulted due to scattering by a target at a first position in the volume, wherein a first acoustic front due to the patterns on the surface of the probe targeting the first position in the volume is distinguishably different from a second acoustic front due to the patterns on the surface of the probe targeting a second position in the volume, wherein a scattered component of a target at the second position interferes with the component of the received acoustic signal that resulted due to scattering by the target at the first position, and wherein prediction of acoustic fronts due to the patterns on the surface of the probe reaching positions in the volume is used to identify the component;
• and,
• outputting an intensity of the identified component at the first position in the volume.

A method, comprising:

• placing an opto-acoustic probe in proximity to a surface of a volume of tissue, the volume of tissue comprising an epidermal layer;
• delivering optical energy into the volume of tissue, wherein a portion of the optical energy is absorbed by the epidermal layer thus producing an upward directed response and a downward directed response;
• receiving acoustic signals from a receiver coupled to the surface of the volume of tissue, wherein the received acoustic signals comprise:
• a direct acoustic return component from the upward directed response of the epidermal layer;
• and,
• a secondary acoustic return component corresponding to an acoustic reflection of the downward directed response of the epidermal layer by a target in the volume;
• processing the received acoustic signals to produce processed signals;
• analyzing the processed signals to determine an auxiliary signal from the direct acoustic return component;
• using the auxiliary signal to compute an output from the processed signals pertaining to the secondary acoustic return component;
• and,
• outputting and image based on the computed output to a display.

A method, comprising:

• acquiring signals for a first frame using an opto-acoustic probe;
• processing data from the signals of the first frame to compute a detected one or more vessels in the first frame;
• determining configurations of the detected one or more vessels of the first frame, wherein the determined configurations are stored in a data structure;
• acquiring signals for an adjacent frame using the opto-acoustic probe;
• processing data from the signals of the adjacent frame to compute a detected one or more corresponding vessels in the adjacent frame, wherein the detected one or more corresponding vessels of the adjacent frame correspond to the detected one or more vessels of the first frame;
• solving for a motion between the first frame and the adjacent frame;
• using the solved motion between the first frame and the adjacent frame to compute a representation of an inter-frame movement of the opto-acoustic probe;
• and,
• outputting the inter-frame movement undergone by the opto-acoustic probe.

A method, comprising:

• placing an opto-acoustic probe comprising a distal surface into contact with a surface of a volume to form a coupling interface, wherein the distal surface comprises a detector array;
• delivering energy to the volume;
• receiving acoustic signals comprising:
• a direct component due to acoustic return signals produced within the volume;
• and,
• a surface component due to an acoustic wavefront propagating substantially proximate to the distal surface where the wavefront reaches elements of the detector array in a sequence, wherein the surface component varies according to at least one parameter that is dependent on properties of the coupling interface or materials proximate thereto;
• processing the acoustic signals to determine the at least one parameter;
• forming an image using the acoustic signals that is spatially representative of the volume, wherein formation of the image is dependent on the at least one parameter;
• and,
• outputting the image to a display.

A system, comprising:

• a light source configured to deliver light energy along a light path towards an energy exit port, the energy exit port is positioned at a distal end of the light path to permit energy to exit the light path, the exit port is configured to be coupled to a volume to deliver energy comprising acoustic energy to the volume, wherein a surface in the light path that is proximate to the energy exit port comprises a plurality of optically interacting modes, each optically interacting mode is configured to interact with the light energy in the light path, the optically interacting modes are selected from the group consisting of:
• i) optically reflective mode to substantially reflect light energy and produce substantially no acoustic energy response;
• ii) optically absorbing mode to substantially absorb light energy and produce an acoustic energy response, wherein a portion of the produced acoustic energy exits the energy port;
• and,
• iii) optically transparent mode to substantially transmit light energy and produce substantially no acoustic energy response, wherein the transmitted light energy exits the energy exit port;
• and,
• wherein the plurality of optically interacting modes are arranged to comprise a pattern to permit shaping of delivered acoustic energy.

A method, comprising:

• receiving a plurality of acoustic return signals, each signal received from a position proximate to an outer surface of a volume in response to delivery of electromagnetic energy to the volume;
• applying a pattern detection classifier to each received signal to produce a plurality of classifier output signals, each classifier output signal is representative of an indicator strength as a function of time in each received signal;
• reconstructing a spatial representation of the volume from the plurality of classifier output signals;
• and,
• outputting an image based on the reconstructed spatial representation.