Method and apparatus for harmonic imaging using multiple transmissions

A method for harmonic ultrasound imaging comprising the steps of

• providing a first transmitting event in the near field and in the far field, the ultrasonic energy being transmitted by means of a first transmit wave form at the center frequency of f1,
• receiving the corresponding echo from the first transmitting event,
• extracting the tissue generated harmonic signal that is centered around 2f1 for the near field and the far field,
• generating a second transmitting event in the near field and the far field at the center frequency of f2,
• using a time-gain-varying filter to extract signals for the near and far fields,
• wherein the extracted signals associated with the first transmitting event reside in a frequency band that has significant overlap with the frequency band associated with the second transmitting event.

A method for harmonic ultrasound imaging using multiple transmissions comprising the steps of

• providing a first transmitting event used for even scan lines in the near field and in the far field,
• extracting a first echo signal associated with the first transmitting event,
• filtering the first echo signal with a demodulation filter,
• providing a second transmitting event used for odd scan lines in the near field and in the far field,
• extracting a second echo signal associated with the second transmitting event,
• filtering the second echo signal with a time-gain-varying filter, and
• amplitude detecting and scan converting the extracted echo signals,
• wherein composite imaging of the extracted signals results in similar speckle size across the entire image.

An ultrasound imaging device that uses multiple transmissions to create the scan line of an ultrasound image which comprises

• means for providing a first transmitting event,
• means for extracting a tissue generated harmonic signal associated with the first transmitting event in the near field,
• means for providing a second transmitting event, and
• means for extracting a fundamental echo signal associated with the second transmitting event in the far field,
• wherein the composite imaging of the extracted signals results in similar speckle size across the entire image.

An ultrasound imaging device which comprises

• means for providing a first transmitting event in the near field and in the far field, the ultrasonic energy being transmitted by means of a first transmit wave form at the center frequency of f1,
• means for receiving the corresponding echo from the first transmitting event,
• means for extracting the tissue generated harmonic signal that is centered around 2f1 for the near field and the far field,
• means for generating a second transmitting event in the near field and the far field at the center frequency of f2,
• a time-gain-varying filter to extract signals for the near and far fields,
• wherein the extracted signals associated with the first transmitting event reside in a frequency band that has significant overlap with the frequency band associated with the second transmitting event.

An ultrasound imaging device which comprises

• means for providing a first transmitting event used for even scan lines in the near field and in the far field,
• means for extracting a first echo signal associated with the first transmitting event,
• means for filtering the first echo signal with a demodulation filter,
• means for providing a second transmitting event used for odd scan lines in the near field and in the far field,
• means for extracting a second echo signal associated with the second transmitting event,
• a time-gain-varying filter for filtering the second echo signal, and
• means for amplitude detecting and scan converting the extracted echo signals,
• wherein composite imaging of the extracted signals results in similar speckle size across the entire image.