System for phase inversion ultrasonic imaging

Abstract

A system and method for ultrasonic imaging utilizing multiple sets of transmit pulses differing in amplitude, frequency, phase, and/or pulse width. One embodiment has phase differences between the k transmit signal as 360 k degrees providing for constructive interference of the k th order harmonic pulse, while an amplitude modulation of each transmit profile is constant between sets. These sets of pulses are transmitted into media of interest and received echoes from these pulses are combined to form an averaged signal. The averaged pulses represent the net common mode signal received from each of the transmit sets. This combined signal set is used to reconstruct an ultrasound image based on broad beam reconstruction methodology.

What is claimed is: 
     
       1. A system for ultrasonic imaging of non-linear media, comprising:
 a signal generator unit for generating that generates at least two out-of-phase pulses, wherein said the signal generator unit may modulate modulates at least two sine waves with an envelope function to produce a modified version of said the at least two out-of-phase pulses, said the signal generator unit further converting said the at least two out-of-phase pulses into at least two out-of-phase acoustical pulses; 
 a signal transmitter unit coupled to said the signal generator unit for transmitting said that transmits the at least two out-of-phase acoustical pulses into media of interest; 
 a receiver and that tracks the changes in frequency with time of the at least two out-of-phase acoustic pulses; 
 a raw data averager unit for receiving said that receives the at least two out-of-phase acoustical pulses modified by said the media of interest, and reduces a fundamental frequency of the at least two out-of phase acoustic pulses according to the tracked changes in frequency with time; wherein data from said the at least two modified out-of-phase acoustical pulses are averaged in to form a data set as a function of channel number, frequency, and time; and 
 a data processing unit processor coupled to said the receiver and raw data averager unit, wherein said the data processing unit processor constructs image data for visualizing the media from said modified acoustical pulses, the averaged data; and 
 an image display, wherein an output from saidthe data processing unitprocessor is further coupled to anthe image display unitto display the constructed image data for visualizing the media. 
 
     
     
       2. The system of  claim 1 , wherein said the signal transmitter unit comprises a power amplifier that amplifies the at least two out-of-phase acoustical pulses, a transmit/receive switch that selectively couples the amplified at least two out-of-phase acoustical pulses to a transducer, and a wherein the transducer transmits the amplified at least two out-of-phase acoustical pulses sequentially. 
     
     
       3. The system of  claim 2 , further comprising a digital delay circuit coupled between the signal generator and the power amplifier to delay the at least two out-of-phase acoustical pulses, and wherein the power amplifier amplifies the delayed at least two out of phase acoustical pulses. 
     
     
       4. The system of  claim 2 , further comprising an analog delay circuit coupled between the signal generator and the power amplifier to delay the at least two out-of-phase acoustical pulses, and wherein the power amplifier amplifies the delayed at least two out of phase acoustical pulses. 
     
     
       5. The system of  claim 2 , further comprising a channel gain circuit coupled between the signal generator and the power amplifier to drive the power amplifier as a function of channel number and time. 
     
     
       6. The system of  claim 1 , wherein said the receiver and raw data averager unit comprises a transducer that receives the at least two acoustical pulses modified by the media of interest, a transmit/receive switch, that couples the transducer to an analog-to-digital converter that digitizes the modified at least two acoustical pulses, and an averager that averages the digitized at least two acoustical pulses to form the data set as a function of channel number and time. 
     
     
       7. The system of  claim 6 , wherein said the receiver and raw data averager unit further comprises a power amplifier that amplifies the modified at least two acoustical pulses, a bandpass filter that filters the amplified at least two acoustical pulses, and a baseband filter that further filters the amplified at least two acoustical pulses. 
     
     
       8. The system of  claim 6 , wherein said the receiver and raw data averager unit further comprises an in-phase and quadrature mixer coupled between the power amplifier and the averager. 
     
     
       9. The system of  claim 1 , wherein said the signal generator unit and said the receiver and raw data averager unit share a transducer that transmits the at least two out-of-phase acoustical pulses and that receives the at least two modified acoustical pulses. 
     
     
       10. The system of  claim 1 , wherein said the data processing unit comprises an in-phase and quadrature mixer that downconverts the received at least two modified acoustic pulses from a first frequency to a second frequency, a digital signal processor that constructs the acoustic image data based on the side-band signal, an acoustic image data buffer that buffers the acoustic image data, and a scan converter that converts the buffered acoustic image data from a first coordinate system to a second coordinate system for display on the image display. 
     
     
       11. The system of  claim 1 , wherein said the data processing unit processor comprises an in-phase and quadrature mixer that downconverts the received at least two modified acoustic pulses from a first frequency to a second frequency, an application specific integrated circuit that constructs the acoustic image data based on the side-band signal, an acoustic image data buffer that buffers the acoustic image data, and a scan converter that converts the buffered acoustic image data from a first coordinate system to a second coordinate system for display on the image display. 
     
     
       12. A system for ultrasonic imaging of non-linear media, the system comprising:
 a signal generator for generating at least two out-of-phase pulses, wherein the signal generator modulates at least two sine waves with an envelope function to produce a modified version of the at least two out-of-phase pulses, the signal generator further converting the at least two out-of-phase pulses into at least two out-of-phase acoustical pulses having different frequencies and different amplitudes;   a signal transmitter coupled to the signal generator for transmitting the at least two out-of-phase acoustical pulses into non-linear media of interest;   a receiver that tracks the changes in frequency with time of the at least two out-of phase acoustic pulses;   raw data averager for receiving the at least two out-of-phase acoustical pulses modified by the non-linear media of interest, and reducing a fundamental frequency of the at least two out-of phase acoustic pulses according to the tracked changes in frequency with time, wherein data from the at least two modified out-of-phase acoustical pulses are averaged in a data set as a function of channel number, frequency, and time; and   a data processor coupled to the receiver and raw data averager, wherein the data processor constructs image data for visualizing the non-linear media from the modified out-of-phase acoustical pulses; and   an image display, wherein an output from the data processor is further coupled to the image display to display the constructed image data for visualizing the non-linear media.   
     
     
       13. A system for ultrasonic imaging non-linear, the system comprising:
 a signal generator for generating at least two out-of-phase pulses, wherein the signal generator modulates at least two sine waves with an envelope function to produce a modified version of the at least two out-of-phase pulses, the signal generator further converting the at least two out-of-phase pulses into at least two out-of-phase acoustical pulses having different pulse widths, and wherein each of the at least two out-of-phase acoustic pulses changes in frequency with time;   a signal transmitter coupled to the signal generator for transmitting the at least two out-of-phase acoustical pulses into media of interest;   a receiver that tracks the changes in frequency with time of the at least two out-of phase acoustic pulses;   raw data averager for receiving the at least two out-of-phase acoustical pulses modified by the non-linear media of interest, and reducing a fundamental frequency of the at least two out-of phase acoustic pulses according to the tracked changes in frequency with time, wherein data from the at least two modified out-of-phase acoustical pulses are averaged in a data set as a function of channel number, frequency, and time; and   a data processor coupled to the receiver and raw data averager, wherein the data processor constructs image data from the modified out-of-phase acoustical pulses; and   an image display, wherein an output from the data processor is further coupled to the image display to display the constructed image data.