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. 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.

The invention claimed is: 
     
         1 . A portable ultrasound system for scanning a region of interest with ultrasound energy to image the region of interest comprising:
 a battery powered, handheld processor housing having a display, a beamformer device and a system controller connected to the beamformer device;   a data processing system within the handheld processor housing, the data processing system having a processor that receives mapped data, the data processing system being programmed to perform a down conversion operation, a scan conversion operation and a Doppler processing operation that applies a programmable filter, the handheld processor housing further including a memory in the processor housing that is electrically connected to the data processing system, the memory having stored therein a sequence of executable instructions that are used to select a pulse repetition frequency from a plurality of selectable values and to apply the programmable filter to ultrasound image data, the programmable filter including a wall filter having a plurality of selectable values, the sequence of instructions configured to execute a calculation of an autocorrelation function and an autocorrelation phase such that the plurality of parallel processing units generate Doppler data; and   a graphical user interface configured to operate on the display such that a user can adjust the programmable filter with a first control window and adjust color priority with a second control window to change a displayed color gain of an 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 data processing system includes a parallel computing element having a multiplier and an adder. 
     
     
         5 . The ultrasound system of  claim 1  wherein the data 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 with the data processing system having a computation device including an MMX or floating point processor. 
     
     
         7 . The ultrasound system of  claim 1  wherein the data 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 an 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 wall filter has a selected value that is a function of the pulse repetition frequency. 
     
     
         10 . The ultrasound system of  claim 1  wherein the data processing system determines a tissue motion velocity. 
     
     
         11 . The ultrasound system of  claim 1  wherein the data processing system compares a Doppler signal to a threshold value such that if the Doppler signal is larger than 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 at least one of a B-mode value, a tissue motion velocity and a high pass filtered Doppler velocity. 
     
     
         13 . The ultrasound system of  claim 1  wherein the graphical user interface further includes display of a filter adjustment setting. 
     
     
         14 . A method for Doppler processing of an ultrasound image on a portable ultrasound system comprising:
 processing ultrasound image data with a battery powered, handheld display device that includes a beamformer device, a system controller to control beamformer device operation, a flat panel display, and a programmable data processing system having a processor configured to perform a down conversion operation, a scan conversion operation and a Doppler processing operation, the portable ultrasound system including a memory that is electrically connected to the programmable data processing system, the memory having stored therein a sequence of instructions executed with the processor to use a pulse repetition frequency, to apply a programmable wall filter to image data and to execute further instructions for a calculation of an autocorrelation function and calculation of an autocorrelation phase to perform Doppler processing of the image data;   using a graphical user interface operating to select a pulse repetition frequency with a first control window shown on the display and select a wall filter value with a second control window shown on the display; and   performing a Doppler processing operation using the processor of the programmable data processing system 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 value based on the pulse repetition frequency to display low velocity tissue motion, the wall value being between 1 percent and 25 percent of the pulse repetition frequency. 
     
     
         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 . The method of  claim 14  further comprising determining a phase shift of the auto-correlation function to generate a monotonic function for all values of the phase shift corresponding to a range of Doppler velocities. 
     
     
         22 . 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. 
 
     
     
         23 . The method of  claim 14  wherein the programmable data processing system includes at least one parallel processing unit that executes at least one of Single Instruction Multiple Data instructions and Multiple instruction Multiple Data instructions. 
     
     
         24 . 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 a lumen within a body. 
     
     
         25 . 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. 
     
     
         26 . The method of  claim 14  further comprising determining a phase shift value and optionally setting the phase shift to zero. 
     
     
         27 . The method of  claim 26  further comprising applying a spatial low pass filter to smooth phase shift values. 
     
     
         28 . The method of  claim 27  further comprising converting phase shift data to color index data. 
     
     
         29 . The method of  claim 26  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. 
     
     
         30 . The method of  claim 14  further comprising adjusting color priority with an adjustable control. 
     
     
         31 . A portable ultrasound imaging apparatus comprising:
 a battery powered, handheld display device including a touchscreen display and a data processing module that is configured to perform a down conversion operation, a scan conversion operation and a Doppler processing operation, the display device being connected to a transducer array;   a memory operably coupled to the data processing module, wherein the memory stores executable instructions that cause the data processing module to:   select a pulse repetition frequency using a first control window of a graphical user interface that is displayed on the touchscreen display;   calculate a power level along a sample line with the data processing module and compare the power level to a threshold;   apply a programmable filter to ultrasound image data including a wall filter value selected from a plurality of wall filter values displayed with a second control window of the graphical user interface, the selected wall filter value being a function of the pulse repetition rate to generate filtered Doppler image data;   calculate, in response to executing instructions with the data processing module, a plurality of autocorrelation values using the filtered Doppler image data;   calculate, in response to executing instructions with the data processing module, a phase shift of an autocorrelation phase to generate a monotonic function for all values of the phase shift corresponding to a range of Doppler velocities;   convert, in response to executing instructions, the calculated phase shift to an index with the data processing module; and   display a plurality of images including at least one of color Doppler, directional power Doppler, power Doppler and pulsed wave Doppler on the touchscreen display of the handheld display device.   
     
     
         32 . The apparatus of  claim 31  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. 
     
     
         33 . The apparatus of  claim 31  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. 
     
     
         34 . The apparatus of  claim 31  wherein the programmable filter comprises a high pass filter. 
     
     
         35 . The apparatus of  claim 31  further comprising a transducer array connected to the handheld display device that comprises a laptop or palmtop device having a plurality of parallel processing units. 
     
     
         36 . The apparatus of  claim 35  wherein the handheld display device includes a beamformer and a system controller. 
     
     
         37 . The system of  claim 1  wherein the handheld processor housing comprises a laptop computer. 
     
     
         38 . The system of  claim 1  wherein the handheld processor housing comprises a palm held computer. 
     
     
         39 . The method of  claim 14  wherein the graphical user interface is operable to select a Doppler scan area within a displayed image wherein an insonating beam emitted by a transducer array is at an angle of 60 degrees or less relative to blood flow within the Doppler scan area. 
     
     
         40 . The method of  claim 39  further comprising selecting a frame rate in response to a selected scan area.