Ultrasound imaging system

Abstract

The present invention is directed to an ultrasound imaging system and method for Doppler processing of data. The ultrasonic imaging system efficiently addresses the data computational and processing needs of Doppler processing. Software executable sequences in accordance with a preferred embodiment of the present invention determines the phase shift and the auto-correlation phase of filtered image data. In a preferred embodiment, the system of ultrasonic imaging also includes a sequence of instructions for Doppler processing that provides the functions for demodulation, Gauss Match filtering, auto-correlation calculation, phase shift calculation, frame averaging, and scan conversion implemented with Single Instruction Multiple Data (SIMD) or Multiple Instruction Multiple Data (MIMD) instructions. In a preferred embodiment, the ultrasound imaging system of the present invention includes a processing module; and memory operable coupled to the processing module, wherein the memory stores operational instructions that cause the processing module to map serial data to vector representation, calculate an auto-correlation function of the data, calculate a phase shift of the auto-correlation function to generate a monotonic function covering all values of the phase shift corresponding to a range of Doppler velocities and display the resultant images, for example, as color images.

1 . An ultrasound system for scanning a region of interest with ultrasound energy to image the region of interest comprising: 
 a data processing system including a Doppler processing system having a programmable filter and a memory coupled to the processing system, the memory having stored therein a sequence of instructions to apply the filter to an ultrasound image; and    a user interface to adjust color priority of the ultrasound image.    
   
   
       2 . The ultrasound system of  claim 1  wherein the programmable filter comprises a high pass filter.  
   
   
       3 . The ultrasound system of  claim 2  wherein the high pass filter comprises a Butterworth filter.  
   
   
       4 . The ultrasound system of  claim 1  wherein the Doppler parallel computing element including a multiplier and an adder.  
   
   
       5 . The ultrasound system of  claim 1  wherein the Doppler processing system executes at least one of Single Instruction Multiple Data instructions and Multiple Instruction Multiple Data instructions.  
   
   
       6 . The ultrasound system of  claim 1  wherein Doppler processing is executed in a computation device having an MMX or floating point processor.  
   
   
       7 . The ultrasound system of  claim 1  wherein the Doppler processing system further comprises a directional power Doppler mode, a power Doppler mode and a pulsed wave Doppler mode.  
   
   
       8 . The ultrasound system of  claim 1  further comprising adjustable control for one of at least scan area selection, velocity display, steering angles, color inversion, color gain, color priority, color persistence, color baseline and frame rate.  
   
   
       9 . The ultrasound system of  claim 1  wherein the programmable filter comprises a wall filter.  
   
   
       10 . The ultrasound system of  claim 1  wherein the processor determines a tissue motion velocity.  
   
   
       11 . The ultrasound system of  claim 1  wherein the processor compares a Doppler signal to a threshold value such that if the Doppler signal is larger then the threshold value, a phase shift of the Doppler signal is set to zero.  
   
   
       12 . The ultrasound system of  claim 11  wherein the threshold value is selected from the group consisting of B-mode value, tissue motion velocity and high pass filtered Doppler velocity.  
   
   
       13 . The ultrasound system of  claim 1  further comprising a graphical user interface that includes a display of a filter adjustment setting.  
   
   
       14 . A method for Doppler processing of an ultrasound image comprising: 
 processing ultrasound image data with a Doppler processing system having a microprocessor and a memory coupled to the microprocessor having stored therein a sequence of instructions that applies a programmable filter to the image data and executes Doppler processing of the image data; and    performing a Doppler processing operation to form an image of the region of interest.    
   
   
       15 . The method of  claim 14  further comprising performing Doppler processing including one of color Doppler, directional power Doppler, power Doppler and pulsed wave Doppler.  
   
   
       16 . The method of  claim 14  further comprising removing low frequency signals from the image data with the filter.  
   
   
       17 . The method of  claim 14  wherein a color Doppler image is overlaid with a B-mode image.  
   
   
       18 . The method of  claim 16  further comprising adjusting a wall filter setting to display low velocity tissue motion.  
   
   
       19 . The method of  claim 14  further comprising filtering the image data with a Butterworth filter.  
   
   
       20 . The method of  claim 14  further comprising adjusting the filter to image cardiac motion.  
   
   
       21 . A computer readable medium having stored therein instructions for causing a processing unit to execute the steps of the method of  claim 14 .  
   
   
       22 . The method of  claim 14  wherein the sequence of instructions perform a filter operation further comprising determining a phase shift of an auto-correlation function to generate a monotonic function for all values of the phase shift corresponding to a range of Doppler velocities.  
   
   
       23 . The method of  claim 14  wherein the sequence of instructions further comprises: 
 filtering the data to remove low frequency signals;    averaging a plurality of frames of data;    converting phase shift data to an index;    converting the phase shift data from scan to raster coordinates; and    displaying a plurality of images.    
   
   
       24 . The method of  claim 14  further comprising at least one parallel processing element.  
   
   
       25 . The method of  claim 24  wherein at least one parallel processing element executes at least one of Single Instruction Multiple Data instructions and Multiple Instruction Multiple Data instructions.  
   
   
       26 . The method of  claim 14  wherein the Doppler processing further comprises displaying at least one of the presence, direction, and relative velocity of blood flow, perfusion and contour of lumens.  
   
   
       27 . The method of  claim 14  further comprising providing an adjustable control for at least one of scan area selection, velocity display, steering angles, color inversion, color gain, color priority, color persistence, color baseline and frame rate.  
   
   
       28 . The method of  claim 14  further comprising determining a phase shift value and optionally setting the phase shift to zero.  
   
   
       29 . The method of  claim 28  further comprising applying a spatial low pass filter to smooth phase shift values.  
   
   
       30 . The method of  claim 29  further comprising converting phase shift data to color index data.  
   
   
       31 . The method of  claim 28  wherein the phase shift is set to zero if the power of a Doppler signal prior to application of a high pass filter is larger than a threshold value.  
   
   
       32 . The method of  claim 14  further comprising adjusting color priority with an adjustable control.  
   
   
       33 . An ultrasound imaging apparatus comprising: 
 a memory operably coupled to a processing module, wherein the memory stores operational instructions that cause the processing module to:    apply a programmable filter to ultrasound image data;    calculate a phase shift of a Doppler signal to generate a monotonic function for all values of the phase shift corresponding to a range of Doppler velocities;    convert the phase shift to an index; and    display a plurality of images including at least one of color Doppler, directional power Doppler, power Doppler and pulsed wave Doppler.    
   
   
       34 . The apparatus of  claim 33  wherein the apparatus further comprises a handheld probe operable to transmit an ultrasound image and to obtain data indicative of the flow characteristics of the region of interest.  
   
   
       35 . The apparatus of  claim 33  wherein the plurality of images includes color Doppler images, directional power Doppler images, power Doppler images and pulsed wave Doppler images.  
   
   
       36 . The apparatus of  claim 33  further comprising adjustable controls for one of at least scan area selection, velocity display, steering angles, color inversion, color gain, color priority, color persistence, color baseline and frame rate.  
   
   
       37 . The apparatus of  claim 33  wherein the programmable filter comprises a high pass filter.  
   
   
       38 . The method of  claim 33  further comprising a graphical user interface including a control for the programmable filter.  
   
   
       39 . The apparatus of  claim 33  further comprising a transducer array connected to an interface that is connected to a personal computer having a parallel processor.  
   
   
       40 . The apparatus of  claim 39  wherein the interface includes a beamformer and a system controller.