Interlaved transmit sequences and motion estimation in ultrasound images, and associated systems, devices, and methods

Abstract

Systems, methods, and devices that perform flow scan sequences are provided. In one embodiment, an ultrasound imaging system includes an intraluminal catheter or guidewire, an annular array of acoustic elements positioned around a circumference of the catheter or guidewire, and a processor in communication with the annular array. The processor is configured to activate a first subaperture of the annular array at a first time, thereafter, activate a second interleaving subaperture, and activate the first subaperture again at a different, second time such that the scan sequence moves around the circumference of the catheter or guidewire. Temporal differences between the received ultrasound signals obtained by the first subaperture at the first and second times are determined to detect motion around the annular array. By interleaving subaperture firings, the total number of firings to form an image frame can be reduced.

What is claimed is: 
     
         1 . An intravascular ultrasound (IVUS) imaging system, comprising:
 an IVUS catheter comprising an annular array of acoustic elements; and   a processor configured for communication with the annular array and a display, wherein the processor is configured to:
 activate a plurality of sub-apertures of the annular array to perform a sequence of single transmit firings, wherein each sub-aperture comprises a different subset of the acoustic elements; 
 receive ultrasound signals obtained based on the sequence; 
 determine temporal differences between the received ultrasound signals; 
 detect motion in a blood vessel based on the determined temporal differences; and 
 output a visual representation of the detected motion to the display, 
   wherein the sequence comprises a first single transmit firing by a first sub-aperture and a second single transmit firing by the first sub-aperture,   wherein each subsequent single transmit firing in the sequence occurs directly after a preceding single transmit firing,   wherein each subsequent single transmit firing is performed by a different sub-aperture than the preceding single transmit firing such that the second single transmit firing by the first sub-aperture does not occur directly after the first single transmit firing by the first sub-aperture.   
     
     
         2 . The IVUS imaging system of  claim 1 , wherein the processor is configured to activate a subset of the plurality of sub-apertures between the first single transmit firing by the first sub-aperture and the second single transmit firing by the first sub-aperture. 
     
     
         3 . The IVUS imaging system of  claim 2 , wherein the subset of the plurality of sub-apertures completes a revolution around the annular array before the second single transmit firing. 
     
     
         4 . The IVUS imaging system of  claim 3 , wherein the subset of the plurality of sub-apertures comprises all of the sub-apertures of the annular array except for the first sub-aperture. 
     
     
         5 . The IVUS imaging system of  claim 4 , wherein the subset of the plurality of sub-apertures comprises a consecutive subset. 
     
     
         6 . The IVUS imaging system of  claim 4 , wherein the subset of the plurality of sub-apertures comprises a non-consecutive subset. 
     
     
         7 . The IVUS imaging system of  claim 6 ,
 wherein the non-consecutive subset comprises an interval of M subapertures,   wherein a total number of the plurality of sub-apertures of the annular array is divisible by M, and   wherein the non-consecutive subset is less than the total number of sub-apertures.   
     
     
         8 . The IVUS imaging system of  claim 6 ,
 wherein the non-consecutive subset comprises an interval of M subapertures   wherein a total number of the plurality of sub-apertures of the annular array is not divisible by M, and   wherein the non-consecutive subset is less than the total number of the plurality of sub-apertures.   
     
     
         9 . The IVUS imaging system of  claim 2 , wherein the subset of the plurality of sub-apertures completes only part of a revolution around the annular array before the second single transmit firing. 
     
     
         10 . The IVUS imaging system of  claim 1 , wherein the sequence further comprises a third single transmit firing by the first sub-aperture and a fourth single transmit firing by the first sub-aperture. 
     
     
         11 . The IVUS imaging system of  claim 10 ,
 wherein the third single transmit firing is after the first single transmit firing and the fourth single transmit firing is after the second single transmit firing,   wherein the processor is further configured to:
 average the received ultrasound signals obtained based on the first single transmit firing and the third single transmit firing; and 
 average the received ultrasound signals obtained based on the second single transmit firing and the fourth single transmit firing. 
   
     
     
         12 . The IVUS imaging system of  claim 1 , wherein the processor is further configured to:
 generate an ultrasound image;   generate a flow map based on the detected motion;   modify the ultrasound image by coloring portions of the ultrasound image based on the flow map or overlaying the flow map on the ultrasound image; and   output the modified ultrasound image to the display.   
     
     
         13 . The IVUS imaging system of  claim 1 , wherein the sequence further comprises a third single transmit firing by a second sub-aperture occurring directly after the first single transmit firing by the first sub-aperture.