Systems and methods for ultrasound imaging

An ultrasound apparatus, comprising:

• a plurality of transmitters configured to transmit acoustic energy to a tissue of an animal having an anatomy through a coupling medium, such that said acoustic energy becomes scattered by an object in said tissue;
• a plurality of receivers configured to receive said scattered energy and produce respective analog echo signals;
• a signal processing component configured to digitize said analog echo signals so as to produce respective digitized signals;
• a processing module configured so as to:
• estimate a tissue configuration, including positions of one or more boundaries between a plurality of regions and speeds of sound in each of said plurality of regions, each of said plurality of regions having a thickness;
• calculate a plurality of indices, each of said plurality of indices representing a travel time of said acoustic energy from a transmitter to a voxel in a proposed image plane and from said voxel to a receiver, said travel time determined based on refraction at each of said boundaries;
• produce a set of object data by combining selected portions of said digitized signals, each of said selected portions determined based on said plurality of indices;
• and
• repeat said calculation of said plurality of indices and said production of said set of object data while varying, for at least one of said plurality of regions, at least one of thickness and speed of sound, until a desired quality for said set of object data for said tissue is obtained.

An ultrasound apparatus, comprising:

• a plurality of transmitters configured to transmit acoustic energy to a tissue of an animal having an anatomy through a coupling medium, such that said acoustic energy becomes scattered by an object in said tissue;
• a plurality of receivers configured to receive said scattered energy and produce respective analog echo signals;
• a signal processing component configured to digitize said analog echo signals so as to produce respective digitized signals;
• a processing module configured so as to:
• calculate a plurality of indices, each of said plurality of indices representing a travel time of said acoustic energy from a transmitter to a voxel in a proposed image plane and from said voxel to a receiver, said travel time determined based on assumed constant speeds of sound in said coupling medium and in said tissue;
• obtain a first optimized focus within a field of view of said tissue while varying the speed of sound in said tissue;
• postulate the presence of a boundary within said field of view so as to form two layers having thicknesses on both sides of said boundary;
• obtain a second optimized focus within said two layers while varying said thicknesses and speeds of sound in said two layers;
• and
• compare said first and second optimized focuses, and discard the second optimized focus if the second optimized focus is not better than the first optimized focus.

An ultrasound apparatus for imaging a generally layered portion of anatomy, comprising:

• a plurality of transmitters configured to transmit acoustic energy to a tissue of an animal having an anatomy through a coupling medium, such that said acoustic energy becomes scattered by an object in said tissue;
• a plurality of receivers configured to receive said scattered energy and produce respective analog echo signals;
• a signal processing component configured to digitize said analog echo signals so as to produce respective digitized signals;
• a processing module configured so as to:
• estimate a speed of sound in a first layer encountered by said acoustic energy;
• calculate a plurality of indices, each of said plurality of indices representing a travel time of said acoustic energy from a transmitter to a voxel in said first layer and from said voxel to a receiver, and construct a set of object data based on said plurality of indices;
• obtain an optimized focus in said first layer while varying the speed of sound in said first layer;
• determine a location of a first interface that forms a boundary between said first layer and a second layer, said first interface determined based on said optimized focus in said first layer;
• estimate a speed of sound in said second layer;
• calculate a plurality of adjustments to said plurality of indices based on refraction across said first interface;
• and
• obtain an optimized focus in said second layer while varying the speed of sound in said second layer.

An ultrasound apparatus for imaging a portion of anatomy having distinct regions with different speeds of sound, comprising:

• a plurality of transmitters configured to transmit acoustic energy to a tissue of an animal having an anatomy through a coupling medium, such that said acoustic energy becomes scattered by an object in said tissue;
• a plurality of receivers configured to receive said scattered energy and produce respective analog echo signals;
• a signal processing component configured to digitize said analog echo signals so as to produce respective digitized signals;
• a processing module configured so as to:
• calculate a plurality of first indices, each of said plurality of first indices representing a travel time of said acoustic energy along an assumed path from a transmitter to a voxel in said tissue and from said voxel to a receiver, said travel time determined based on an estimated speed of sound in said tissue;
• produce a first set of object data by combining first selected portions of said digitized signals, each of said first selected portions determined based on said first indices;
• determine a location of one or more interfaces based on said first set of object data, said one or more interfaces defining regions of interest in said tissue;
• calculate plurality of second indices for voxels in said regions of interest, each of said plurality of second indices determined by an adjustment to at least one of said plurality of first indices due to refraction of said acoustic energy at said one or more interfaces, said adjustment determined based on said estimated speed of sound;
• produce a second set of object data by combining second selected portions of said digitized signals, each of said second selected portions determined based on said plurality of second indices;
• and
• obtain an optimized object data by varying speed of sound in at least one of said regions of interest.

A method of imaging a portion of anatomy with ultrasound, the method comprising:

• for each of a plurality of transmitters,
• transmitting acoustic energy from a transmitter to a tissue of an animal having an anatomy through a coupling medium such that said acoustic energy becomes scattered by an object in said tissue;
• receiving said scattered energy at a plurality of receivers so as to produce respective analog echo signals;
• and
• digitizing said analog echo signals so as to produce respective digitized signals;
• calculating a plurality of first indices, each of said plurality of first indices representing a travel time of said acoustic energy along an assumed path from a transmitter to a voxel in a proposed image plane and from said voxel to a receiver;
• producing a first set of object data by combining first selected portions of said digitized signals, each of said first selected portions determined based on said plurality of first indices;
• determining a location of a skin surface of said anatomy, said skin surface representing a scattering interface;
• calculating a plurality of second indices for said voxels in said proposed image plane, said voxels being located on the opposite side of said skin surface with respect to said plurality of transmitters, each of said plurality of second indices determined by an adjustment to at least one of said plurality of first indices due to refraction of said acoustic energy at said scattering interface, said adjustment determined based on assumed sound speeds in said coupling medium and in said tissue between said scattering interface and said object;
• and
• producing a second set of object data by combining second selected portions of said digitized signals, each of said second selected portions determined based on said plurality of second indices.

A method of imaging a portion of anatomy with ultrasound, the method comprising:

• for each of a plurality of transmitters,
• transmitting acoustic energy from a transmitter to a tissue of an animal having an anatomy through a coupling medium such that said acoustic energy becomes scattered by an object in said tissue;
• receiving said scattered energy at a plurality of receivers so as to produce respective analog echo signals;
• and
• digitizing said analog echo signals so as to produce respective digitized signals;
• estimating a tissue configuration, including positions of one or more boundaries between a plurality of regions and speeds of sound in each of said plurality of regions, each of said plurality of regions having a thickness;
• calculating a plurality of indices, each of said plurality of indices representing a travel time of said acoustic energy from a transmitter to a voxel in a proposed image plane and from said voxel to a receiver, said travel time determined based on refraction at each of said boundaries;
• producing a set of object data by combining selected portions of said digitized signals, each of said selected portions determined based on said plurality of indices;
• and
• repeating said calculation of said plurality of indices and said production of said set of object data while varying, for at least one of said plurality of regions, at least one of thickness and speed of sound, until a desired quality for said set of object data for said tissue is obtained.

A method of imaging a portion of anatomy with ultrasound, the method comprising:

• for each of a plurality of transmitters,
• transmitting acoustic energy from a transmitter to a tissue of an animal having an anatomy through a coupling medium such that said acoustic energy becomes scattered by an object in said tissue;
• receiving said scattered energy at a plurality of receivers so as to produce respective analog echo signals;
• and
• digitizing said analog echo signals so as to produce respective digitized signals;
• calculating a plurality of indices, each of said plurality of indices representing a travel time of said acoustic energy from a transmitter to a voxel in a proposed image plane and from said voxel to a receiver, said travel time determined based on assumed constant speeds of sound in said coupling medium and in said tissue;
• obtaining a first optimized focus within a field of view of said tissue while varying the speed of sound in said tissue;
• postulating the presence of a boundary within said field of view so as to form two layers-having thicknesses on both sides of said boundary;
• obtaining a second optimized focus within said two layers while varying said thicknesses and speeds of sound in said two layers;
• and
• comparing said first and second optimized focuses, and discarding the second optimized focus if the second optimized focus is not better than the first optimized focus.

A method of imaging a generally layered portion of anatomy with ultrasound, the method comprising:

• for each of a plurality of transmitters,
• transmitting acoustic energy from a transmitter to a tissue of an animal having an anatomy through a coupling medium such that said acoustic energy becomes scattered by an object in said tissue;
• receiving said scattered energy at a plurality of receivers so as to produce respective analog echo signals;
• and
• digitizing said analog echo signals so as to produce respective digitized signals;
• estimating a speed of sound in a first layer encountered by said acoustic energy;
• calculating a plurality of indices, each of said plurality of indices representing a travel time of said acoustic energy from a transmitter to a voxel in said first layer and from said voxel to a receiver, and construct a set of object data based on said plurality of indices;
• obtaining an optimized focus in said first layer while varying the speed of sound in said first layer;
• determining a location of a first interface that forms a boundary between said first layer and a second layer, said first interface determined based on said optimized focus in said first layer;
• estimating a speed of sound in said second layer;
• calculating a plurality of adjustments to said plurality of indices based on refraction across said first interface;
• and
• obtaining an optimized focus in said second layer while varying the speed of sound in said second layer.

A method of using ultrasound to image a portion of anatomy having distinct regions with different speeds of sound, the method comprising:

• for each of a plurality of transmitters,
• transmitting acoustic energy from a transmitter to a tissue of an animal having an anatomy through a coupling medium such that said acoustic energy becomes scattered by an object in said tissue;
• receiving said scattered energy at a plurality of receivers so as to produce respective analog echo signals;
• and
• digitizing said analog echo signals so as to produce respective digitized signals;
• calculating a plurality of first indices, each of said plurality of first indices representing a travel time of said acoustic energy along an assumed path from a transmitter to a voxel in said tissue and from said voxel to a receiver, said travel time determined based on an estimated speed of sound in said tissue;
• producing a first set of object data by combining first selected portions of said digitized signals, each of said first selected portions determined based on said first indices;
• determining a location of one or more interfaces based on said first set of object data, said one or more interfaces defining regions of interest in said tissue;
• calculating plurality of second indices for voxels in said regions of interest, each of said plurality of second indices determined by an adjustment to at least one of said plurality of first indices due to refraction of said acoustic energy at said one or more interfaces, said adjustment determined based on said estimated speed of sound;
• producing a second set of object data by combining second selected portions of said digitized signals, each of said second selected portions determined based on said plurality of second indices;
• and
• obtaining an optimized object data by varying speed of sound in at least one of said regions of interest.