Method and apparatus for three-dimensional flow imaging using coded excitation

An imaging system comprising:

• a transducer array having a multiplicity of transducer elements for transmitting wave energy centered at a fundamental frequency in response to electrical activation and for transducing returned wave energy into electrical signals;
• a transmitter coupled to said transducer array and programmed to activate a plurality of said transducer elements to transmit focused wave energy encoded with a first Golay code of a Golay code pair during first and third transmit events and transmit focused wave energy encoded with a second Golay code of said Golay code pair during second and fourth transmit events for each of a multiplicity of transmit focal positions in each of a multiplicity of scan planes;
• a receiver programmed to respectively form first through fourth receive signals from electrical signals produced by said plurality of transducer elements subsequent to said first through fourth transmit events respectively for each of a multiplicity of scan lines in each of said scan planes;
• a wall filter programmed with first through fourth sets of filter coefficients to decode and bandpass first through fourth fundamental signal components of said first through fourth receive signals respectively and selectively pass frequencies corresponding to wave energy reflectors moving at a velocity above a predetermined threshold, said wall filter forming a flow signal derived at least in part from said decoded and bandpassed first through fourth fundamental signal components and the selectively passed frequencies for each of said scan lines in each of said scan planes;
• a memory for storing a respective set of flow signals for each of said scan planes to form a data volume;
• a computer programmed to generate imaging data representing a three-dimensional projection of said data volume having a controllable orientation onto an imaging plane by applying a projection transformation to said data volume;
• and
• a subsystem for displaying an image which is a function of said three-dimensional projection.

An imaging system comprising:

• a transducer array having a multiplicity of transducer elements for transmitting wave energy centered at a fundamental frequency in response to electrical activation and for transducing returned wave energy into electrical signals;
• a display monitor for displaying an image;
• and
• a computer programmed to perform the steps of:
• (a) activating transducer elements of said array to transmit focused wave energy encoded with a transmit code during first and second transmit events for each of a multiplicity of transmit focal positions in each of a multiplicity of scan planes;
• (b) forming first and second receive signals from electrical signals produced by said transducer elements subsequent to said first and second transmit events respectively for each of a multiplicity of scan lines in each of said scan planes;
• (c) compressing, bandpassing and wall filtering first and second fundamental signal components of said first and second receive signals respectively to form a flow signal for each of said scan lines in each of said scan planes;
• (d) storing a respective set of flow signals for each of said scan planes to form a data volume;
• (e) generating imaging data representing a three-dimensional projection of said data volume having a controllable orientation onto an imaging plane by applying a projection transformation to said data volume;
• and
• (f) sending said imaging data representing a three-dimensional projection to said display monitor.

An imaging system comprising:

• a transducer array having a multiplicity of transducer elements for transmitting wave energy centered at a fundamental frequency in response to electrical activation and for transducing returned wave energy into electrical signals;
• a display monitor for displaying an image;
• and
• a computer programmed to perform the steps of:
• (a) activating transducer elements of said array to transmit focused wave energy encoded with a first Golay code of a Golay code pair during first and third transmit events and to transmit focused wave energy encoded with a second Golay code of said Golay code pair during second and fourth transmit events for each of a multiplicity of transmit focal positions in each of a multiplicity of scan planes;
• (b) forming first through fourth receive signals from electrical signals produced by said transducer elements subsequent to said first through fourth transmit events respectively for each of a multiplicity of scan lines in each of said scan planes;
• (c) decoding, bandpassing and wall filtering first through fourth fundamental signal components of said first through fourth receive signals respectively to form a flow signal for each of said scan lines in each of said scan planes;
• (d) storing a respective set of flow signals for each of said scan planes to form a data volume;
• (e) generating imaging data representing a three-dimensional projection of said data volume having a controllable orientation onto an imaging plane by applying a projection transformation to said data volume;
• and
• (f) applying said imaging data representing a three-dimensional projection to said display monitor.

A method for imaging flow of blood in a body, comprising the steps of:

• transmitting N encoded focused beams of wave energy having a fundamental frequency for each of a multiplicity of transmit focal positions in each of a multiplicity of scan planes intersecting the body, where N≧2;
• generating echo signals derived from echoes of wave energy returned from the body following each transmission of a focused beam for each of a multiplicity of scan lines in each of said scan planes;
• filtering a fundamental signal component for each of said echo signals to form a flow signal indicative of blood flow for each of said scan lines in each of said scan planes;
• storing a respective set of flow signals for each of said scan planes to form a data volume;
• generating imaging data representing a three-dimensional projection of said data volume having a controllable orientation onto an imaging plane;
• and
• displaying an image as a function of said three-dimensional projection.

A system for imaging flow of blood in a body, comprising:

• a transducer array having a multiplicity of transducing elements;
• a transmitter for activating said transducer array to transmit N encoded focused beams of wave energy having a fundamental frequency for each of a multiplicity of transmit focal positions in each of a multiplicity of scan planes intersecting the body, where N≧2;
• a receiver for receiving echo signals derived from echoes of wave energy returned from the body to said transducer array following each transmission of a focused beam for each of a multiplicity of scan lines in each of said scan planes;
• a filter for filtering a fundamental signal component for each of said echo signals to form a flow signal indicative of blood flow for each of said scan lines in each of said scan planes;
• a memory for storing a respective set of flow signals for each of said scan planes to form a data volume;
• a computer programmed to generate first imaging data representing a three-dimensional projection of said data volume having a controllable orientation onto an imaging plane in a first imaging mode;
• and
• a display subsystem for displaying an image as a function of said three-dimensional projection.

A method of operating an imaging system including a multiplicity of transducer elements for transmitting wave energy in response to electrical activation and for transducing returned wave energy into electrical signals, and a display monitor for displaying an image, said method comprising the steps of:

• (a) activating transducer elements of said array to transmit encoded focused wave energy during first through N-th transmit events for each of a multiplicity of transmit focal positions in each of a multiplicity of scan planes;
• (b) forming first through N-th receive signals from electrical signals produced by said plurality of transducer elements subsequent to said first through N-th transmit events, respectively, for each of a multiplicity of scan lines in each of said scan planes;
• (c) compressing, bandpassing and wall filtering first through N-th fundamental signal components of said first through N-th receive signals, respectively, to form a respective flow signal for each of said scan lines in each of said scan planes;
• (d) storing a respective set of flow signals for each of said scan planes to form a data volume;
• (e) generating imaging data representing a three-dimensional projection of said data volume having a controllable orientation onto an imaging plane by applying a projection transformation to said data volume;
• and
• (f) displaying an image as a function of said three-dimensional projection.

An ultrasound diagnostic system for displaying three-dimensional images of stationary and moving reflectors for an area of interest in a patient, comprising:

• a transmitter for transmitting multiple sequences of at least two B-mode pulses to a volume of interest, wherein said at least two B-mode pulses in at least one sequence are transmitted to a common transmit focal position;
• a receiver for receiving B-mode echo signals containing a fundamental frequency component and being associated with said B-mode pulses, said B-mode echo signals defining a three-dimensional data volume containing B-mode and B-mode flow information;
• a filter for receiving said B-mode echo signals and, based thereon, producing a filtered output signal containing flow image information for moving reflectors in said three-dimensional data volume, said filtered signal containing B-mode information for stationary reflectors in said three-dimentional data volume, said B-mode information for stationary reflectors including said fundamental frequency component;
• and
• a display for displaying a three-dimensional image comprising a B-mode flow image component of moving reflectors and a B-mode image component of stationary reflectors based on said filtered output signal.

An ultrasound imaging system comprising:

• a transmitter for transmitting focused wave energy encoded with a transmit code during first and second transmit events for each of a multiplicity of transmit focal positions in each of a multiplicity of scan planes;
• a receiver for forming first and second receive signals from said first and second transmit events, respectively, for each of a multiplicity of scan lines in each of said scan planes;
• a filter for forming a flow signal from said first and second receive signals for each of said scan lines in each of said scan planes, a first flow signal being based on a weighted sum of said first and second receive signals;
• a computer for generating imaging data representing a three-dimensional projection of a data volume containing a set of flow signals for each scan plane;
• and
• a display for displaying a three-dimensional image which is a function of said three-dimensional projection.

An ultrasound imaging system comprising:

• a transmitter for transmitting broadband focused wave energy encoded with a first Golay code of a Golay code pair during first and third transmit events and for transmitting broadband focused wave energy encoded with a second Golay code of said Golay code pair during second and fourth transmit events for each of a multiplicity of transmit focal positions in each of a multiplicity of scan planes;
• a receiver for forming first through fourth receive signals from said first through fourth transmit events, respectively, for each of a multiplicity of scan lines in each of said scan planes;
• a filter for forming a flow signal from said first through fourth receive signals for each of said scan lines in each of said scan planes;
• a computer for generating imaging data representing a three-dimensional projection of a set of flow signals forming a data volume;
• and
• a display for displaying an image which is a function of said three-dimensional projection.

A method for three-dimensional imaging of stationary and moving reflectors in a body, comprising the steps of:

• transmitting at least two broadband encoded focused beams of wave energy for each of a multiplicity of transmit focal positions in each of a multiplicity of scan planes intersecting the body;
• generating echo signals derived from echoes of wave energy returned from the body following each transmission of a focused beam for each of a multiplicity of scan lines in each of said scan planes;
• forming a B-mode flow signal component and a B-mode signal component indicative of moving reflectors and stationary reflectors, respectively, for each of said scan lines in each of said scan planes based on said echo signals;
• generating imaging data representing a three-dimensional projection of a data volume formed from said B-mode flow and B-mode signal components;
• and
• displaying a three-dimensional image of stationary and moving reflectors as a function of said three-dimensional projection.

A method of operating an imaging system, comprising the steps of:

• (a) transmitting encoded focused wave energy during first through N-th transmit events for each of a multiplicity of transmit focal positions in each of a multiplicity of scan planes;
• (b) forming first through N-th receive signals from said first through N-th transmit events for each of a multiplicity of scan lines in each of said scan planes;
• (c) filtering said first through N-th receive signals based on a weighting sum to form a respective flow signal for each scan line in each of said scan planes;
• (d) generating imaging data representing a three-dimensional projection of a data volume defined by the respective flow signals;
• and
• (e) displaying an image as a function of said three-dimensional projection.