Ultrasound 3d imaging system

Abstract

The present invention relates to an ultrasound imaging system in which the scan head includes a beamformer circuit that performs far field subarray beamforming or includes a sparse array selecting circuit that actuates selected elements. When using a hierarchical two-stage or three-stage beamforming system, three dimensional ultrasound images can be generated in real-time. The invention further relates to flexible printed circuit boards in the probe head. The invention furthermore relates to the use of coded or spread spectrum signalling in ultrasound imaging systems. Matched filters based on pulse compression using Golay code pairs improve the signal-to-noise ratio thus enabling third harmonic imaging with suppressed sidelobes. The system is suitable for 3D full volume cardiac imaging.

1 . A medical ultrasound imaging system comprising:
 a two dimensional transducer array in a probe housing and a first plurality of subarray beamformers in the probe housing such that the transducer array generates a plurality of beams for cardiac imaging.   
     
     
         2 . The system of  claim 1  further comprising a plurality of multiplexor circuits in the probe housing. 
     
     
         3 . The system of  claim 1  wherein the array of transducer elements operates as a sparse array. 
     
     
         4 . The system of  claim 1  further comprising a second plurality of beamformers in a second housing, the second plurality of beamformers being in communication with the probe housing, the second beamformers receiving first image data from the first plurality of subarray beamformers having a plurality of second delay lines that receive first image data, plurality subarray beamformers operating in parallel to provide three dimensional image data. 
     
     
         5 . The system of  claim 1  wherein the second beamformer comprises a second stage beamformers. 
     
     
         6 . The system of  claim 5  further comprising a third stage beamformer. 
     
     
         7 . The system of  claim 1  wherein the system weighs less than 15 lbs. 
     
     
         8 . The system of  claim 7  wherein the system comprises a transducer array in a probe housing that is connected to a processor housing. 
     
     
         9 . The system of  claim 1  further comprising a sparse array transmission system. 
     
     
         10 . The system of  claim 1  further comprising a sparse array receiver system. 
     
     
         11 . The system of  claim 1  further comprising a matched filter. 
     
     
         12 . The system of  claim 1  further comprising a program performing a transmission waveform that is oversampled. 
     
     
         13 . The system of  claim 1  wherein the probe housing further comprises a plurality of flexible cables, each cable connecting a transducer subarray to a circuit board. 
     
     
         14 . The system of  claim 1  wherein the probe housing encloses a plurality of circuit boards, each circuit board having at least one of the first plurality of subarray beamformers, a memory that stores beamformer control data and a multiplexor circuit. 
     
     
         15 . The system of  claim 1  further comprising a flexible circuit. 
     
     
         16 . The system of  claim 15  wherein the flexible circuit comprises a flexible cable. 
     
     
         17 . The system of  claim 15  wherein the flexible circuit comprises a flexible printed circuit. 
     
     
         18 . The system of  claim 11  wherein the matched filter comprises a plurality of weights associated with stages of a delay line. 
     
     
         19 . The system of  claim 1  wherein each beam in the plurality of subarray beamformers is compressed. 
     
     
         20 . The system of  claim 1  wherein the second plurality of beamformers comprise a plurality of digital beamformers. 
     
     
         21 . The system of  claim 20  wherein the first plurality of beamformers comprise charge domain processors. 
     
     
         22 . The system of  claim 1  further comprising a program for storing a spread spectrum excitation waveform. 
     
     
         23 . The system of  claim 1  further comprising a system processor for performing scan conversion. 
     
     
         24 . The system of  claim 1  further comprising a system processor for performing Doppler processing. 
     
     
         25 . The system of  claim 1  wherein the probe housing further comprises a catheter or probe body with the transducer array mounted on a distal region. 
     
     
         26 . The system of  claim 1  wherein the system comprises a cardiac imaging system that simultaneously images the left and right ventricles. 
     
     
         27 . The system of  claim 1  wherein the second housing comprises a processor housing, a display and a control panel weighing less than 15 lbs. 
     
     
         28 . The system of  claim 1  wherein the array has an aperture sized to detect a heart volume of at least 200 ml/m 2  in less than one cardiac cycle. 
     
     
         29 . The system of  claim 1  wherein the system simultaneously generates a plurality of beams for full volume cardiac imaging in less than one cardiac cycle. 
     
     
         30 . A medical ultrasound imaging system comprising:
 a transducer array in a probe housing and a beamformer device for processing ultrasound data, the array being connected to a transmit circuit that actuates transmission of an ultrasound pulse from the array without a third harmonic of a transmission pulse frequency; and   a control circuit that controls the transmission pulse.   
     
     
         31 . The system of  claim 30  further comprising a match filter to filter detected image data to detect a third harmonic with suppressed sidelobes. 
     
     
         32 . The system of  claim 1  wherein the array of transducer elements operates as a sparse array. 
     
     
         33 . The system of  claim 1  further comprising first plurality of beamforming in the probe housing and a second plurality of beamformers in a second housing, the second plurality of beamformers being in communication with the probe housing, the second beamformers receiving first image data from the first plurality of subarray beamformers having a plurality of second delay lines that receive first image data, plurality subarray beamformers operating in parallel to provide three dimensional image data. 
     
     
         34 . The system of  claim 33  wherein the second beamformers comprises a second stage beamformers. 
     
     
         35 . The system of  claim 30  wherein the control circuit actuates transmission of a modified square wave with a suppressed third harmonic. 
     
     
         36 . A method for full volume cardiac ultrasound imaging comprising:
 transmitting ultrasound signals with a two dimensional array of transducer elements in a probe housing, the probe housing including circuitry to transmit a plurality of beams and form full volume cardiac images at a rate of at least 4 full volume cardiac images per second.   
     
     
         37 . The method of  claim 36  further comprising using a second beamformer device in a second housing, the second beamformer device being in communication with the probe housing, the second beamformer device receiving first beamformed image data from first subarrays, the second beamformer device having a plurality of second beamformers, the first subarrays operating in parallel to provide image data. 
     
     
         38 . The method of  claim 36  wherein the array of transducer elements comprises subaperture arrays. 
     
     
         39 . The system of  claim 36  further comprising using an array of transducer elements that is connected with a flexible circuit having the first beamformer device mounted thereon. 
     
     
         40 . The method of  claim 36  further comprising using the second beamformer that comprises a second stage beamformer. 
     
     
         41 . The method of  claim 40  further comprising using a third stage beamformer. 
     
     
         42 . The method of  claim 36  further comprising using a system that comprises a system processor, a display and a control panel that weighs less than 15 lbs. 
     
     
         43 . The method of  claim 36  further comprising using a system that comprises a probe housing that is connected to a processor housing. 
     
     
         44 . The method of  claim 36  further comprising using a flexible circuit board in the probe housing. 
     
     
         45 . The method of  claim 36  further comprising using a flexible cable in the probe housing that connects the transducer array to a circuit board assembly. 
     
     
         46 . The method of  claim 36  further comprising using parallel and serial beamforming. 
     
     
         47 . The method of  claim 36  further comprising performing a transmission waveform that is oversampled. 
     
     
         48 . The method of  claim 42  further comprising performing scan conversion and Doppler processing. 
     
     
         49 . The method of  claim 36  further comprising using a beamformer device to process image data from a volume of at least 200 ml/m 2  during a single cardiac cycle. 
     
     
         50 . The method of  claim 36  further comprising emitting a transmission pulse having a transmission frequency, the pulse being emitted without a third harmonic of the transmission frequency. 
     
     
         51 . The method of  claim 50  further comprising using a match filter to process image data to detect a third harmonic of the transmission frequency. 
     
     
         52 . The method of  claim 51  further comprising using a Golay code match filter. 
     
     
         53 . The method of  claim 50  further comprising using an autocorrelation of a match filter template. 
     
     
         54 . The method of  claim 36  further comprising determining a sum of a first autocorrelation of a match filter template and a second autocorrelation of a match filter template to detect a third harmonic with sidelobe cancellation. 
     
     
         55 . The method of  claim 50  wherein the transmission pulse is a modified square wave pulse. 
     
     
         56 . The method of  claim 36  further comprising using a transducer probe housing having a controller connected to a plurality of subarray beamformer circuits. 
     
     
         57 . The method of  claim 56  wherein the probe housing further comprises a plurality of transmit circuits that controls a corresponding plurality of transducer subarrays. 
     
     
         58 . The method of  claim 56  wherein the probe housing contains a plurality of memory circuits, each memory circuit connected to the plurality of subarray beamformer circuits. 
     
     
         59 . The method of  claim 57  further comprising using a plurality of multiplexer circuits connected to the transmit circuits and the beamformer circuits in the probe housing. 
     
     
         60 . The method of  claim 56  further comprising simultaneously beamforming image data using a plurality of at least 16 transmission beams in parallel to form a 3D image.