Continuous transmit focusing method and apparatus for ultrasound imaging system

An ultrasound imaging system for achieving transmit and receive focusing at every echo location within a region of interest, the system comprising:

• a probe that includes one or more transducer elements for transmitting and receiving ultrasound waves;
• means for generating a sequence of spatially distinct transmit beams which differ in one or more of origin and angle;
• means for determining a transmit beam spacing substantially based upon a combination of actual and desired transmit beam characteristics, thereby achieving a faster echo acquisition rate compared to a transmit beam spacing based upon round-trip transmit-receive beam sampling requirements;
• means for storing coherent receive echo data, from two or more transmit beams of the spatially distinct transmit beams;
• means for combining coherent receive echo data from at least two or more transmit beams to achieve a substantially spatially invariant synthesized transmit focus at each echo location, i.e., to achieve transmit synthesis;
• and
• means for combining coherent receive echo data from each transmit firing to achieve dynamic receive focusing at each echo location.

An ultrasound imaging system for achieving transmit and receive focusing at every echo location within a region of interest, the system comprising:

• a probe that includes one or more transducer elements for transmitting and receiving ultrasound waves;
• and
• a processor;
• wherein the processor
• generates a sequence of spatially distinct transmit beams which differ in one or more of origin and angle;
• determines a transmit beam spacing substantially based upon a combination of actual and desired transmit beam characteristics, thereby achieving a faster echo acquisition rate compared to a transmit beam spacing based upon round-trip transmit-receive beam sampling requirements;
• stores coherent receive echo data, from two or more transmit beams of the spatially distinct transmit beams;
• combines coherent receive echo data from at least two or more transmit beams to achieve a substantially spatially invariant synthesized transmit focus at each echo location, i.e., to achieve transmit synthesis;
• and
• combines coherent receive echo data from each transmit firing to achieve dynamic receive focusing at each echo location.