Method and apparatus for three-dimensional ultrasound imaging using transducer array having uniform elevation beamwidth

A method for three-dimensional imaging of an ultrasound scattering medium in an object volume using a multi-row ultrasound transducer array, comprising the steps of:

• focusing a central row of transducer elements of said array on sample volumes in a near field;
• focusing first and second outer rows of transducer elements of said array on sample volumes in a far field, said near field being located between said far field and said array;
• deriving a first set of pixel data from electrical pulses produced by said central row of transducer elements in response to detection of ultrasound transmitted by said central row and reflected by the scattering medium in near-field sample volumes;
• deriving a second set of pixel data from electrical pulses produced by said central row and said first and second outer rows of transducer elements in response to detection of ultrasound transmitted by said central row and said first and second outer rows and reflected by the scattering medium in far-field sample volumes;
• forming vector data comprising pixel data from said first set and pixel data from said second set;
• storing said vector data;
• retrieving a set of vector data from said memory means corresponding to a volume of interest in the object volume;
• projecting said vector data set onto a first image plane, thereby forming a projected data set representing a first projected image;
• and
• displaying said first projected image.

A system for three-dimensional imaging of an ultrasound scattering medium in an object volume, comprising:

• an ultrasound transducer array for transmitting ultrasound beams and detecting ultrasound echoes reflected in the object volume at predetermined sample volumes, said array comprising a first multiplicity of transducer elements arranged in a central row, a second multiplicity of transducer elements arranged in a first outer row, and a third multiplicity of transducer elements arranged in a second outer row, said central row being between said first and second outer rows, a first multiplicity of signal leads respectively connected to said first multiplicity of transducer elements, and a second multiplicity of signal leads respectively connected to said second and third multiplicities of transducer elements;
• a beamformer comprising a multiplicity of channels for forming transmit and receive beams;
• a first multiplicity of switches for respectively connecting said first multiplicity of signal leads to said multiplicity of beamformer channels in a first switching state;
• a second multiplicity of switches for respectively connecting said second multiplicity of signal leads to said multiplicity of beamformer channels in a second switching state;
• means for deriving pixel data from a multiplicity of receive beams formed by said beamformer channels, each pixel datum corresponding to a respective one of said predetermined sample volumes;
• a memory for storing said pixel data;
• means for retrieving a set of pixel data from said memory means corresponding to a volume of interest in the object volume;
• means for projecting said pixel data set onto a first image plane, thereby forming a projected data set representing a first projected image;
• a display monitor;
• and
• means for displaying said first projected image on said display monitor.

A system for three-dimensional imaging of ultrasound scattering matter in an object volume, comprising:

• an ultrasound transducer array for transmitting ultrasound beams and detecting ultrasound echoes reflected from the object volume, said transducer array comprising a first multiplicity of transducer elements arranged in a central row, a second multiplicity of transducer elements arranged in a first outer row, and a third multiplicity of transducer elements arranged in a second outer row, said central row being between said first and second outer rows, a first multiplicity of signal leads respectively connected to said first multiplicity of transducer elements, and a second multiplicity of signal leads respectively connected to said second and third multiplicities of transducer elements;
• first means for changing the azimuthal focusing of said transducer elements within each row to achieve changes in focal depth;
• second means for changing the elevational focusing of said rows of transducer elements as a function of said focal depth;
• means for coordinating said first and second changing means to acquire a source volume of pixel data derived from sample volumes in said object volume;
• memory means for storing said source volume of pixel data;
• means for retrieving a set of pixel data from said memory means corresponding to a volume of interest in the object volume;
• means for projecting said pixel data set onto a first image plane, thereby forming a projected data set representing a first projected image;
• a display monitor;
• and
• means for displaying said first projected image on said display monitor.