Systems and methods for composite myocardial elastography

Abstract

Systems and methods for composite myocardial elastography are presented. In exemplary embodiments of the present invention an imaging modality field of view, such as, for example, that of ultrasound, can be divided into N sectors, each having 1/Nth of a full field of view. In exemplary embodiments of the present invention a temporal series of 2D ultrasound images for each of the N sectors can be acquired over a duration of one or more periods of a periodic signal. Substantially simultaneously, such a periodic signal can also be acquired, wherein each of said series of 2D ultrasound images for each sector can be triggered using said periodic signal. For example, for ultrasound imaging of the heart, an ECG signal can function as such a periodic signal. The data from the various N sectors can be synchronized in time using the ECG signals, and the ultrasound signals from each of the N sectors combined to generate a series of composite ultrasound images at the frame rate of the individual sectors. In exemplary embodiments of the present invention such a composite image can be further processed to estimate displacement between consecutive frames, remove noise, accumulate displacement with time for an entire cardiac cycle, and derive strain in the cardiac muscle, vessel or any other organ or tissue under motion. In exemplary embodiments of the present invention the derived strain data can be overlaid onto all or part of the composite ultrasound images, and one or more of such overlaid images can be displayed to a user.

1 . A method of imaging of an anatomical object, comprising:
 acquiring a series of images for each of a plurality of sectors over one or more periods of a periodic signal representing movement of at least a portion of the anatomical object, each of the sectors corresponding to a different portion of the anatomical object;   substantially simultaneously acquiring a period of the periodic signal in response to each periodic movement of the anatomical object, each of said series of images for each sector being acquired in response to the periodic signal; and   synchronizing data for each of said plurality of sectors using the periodic signal.   
     
     
         2 . The method of  claim 1 , further comprising combining said data from said plurality of sectors to generate a series of high frame rate composite images. 
     
     
         3 . The method of  claim 2 , further comprising displaying at least one of said series of high frame rate composite images to a user. 
     
     
         4 . The method of  claim 1 , wherein at least one of said images comprises a 2D image. 
     
     
         5 . The method of  claim 1 , wherein at least one of said images comprises a 3D image. 
     
     
         6 . The method of  claim 2 , further comprising estimating one or more displacements between consecutive time frames for one or more windows of said high frame rate composite image. 
     
     
         7 . The method of  claim 6 , further comprising estimating a propagation of said one or more displacements in a waveform. 
     
     
         8 . The method of  claim 7 , further comprising estimating a direction of said propagation of said one or more displacement waves. 
     
     
         9 . The method of  claim 8 , further comprising estimating a velocity of said propagation of said one or more displacement waves. 
     
     
         10 . The method of  claim 7 , wherein said one or more displacement waves comprise one or more electromechanical waves. 
     
     
         11 . The method of  claim 10 , further comprising estimating a direction of propagation of said one or more electromechanical waves. 
     
     
         12 . The method of  claim 11 , further comprising estimating a velocity of propagation of said one or more electromechanical waves. 
     
     
         13 . The method of  claim 7 , wherein said one or more displacement waves comprise one or more mechanical waves. 
     
     
         14 . The method of  claim 13 , further comprising estimating a direction of propagation of said one or more mechanical waves. 
     
     
         15 . The method of  claim 13 , further comprising estimating a velocity of propagation of said one or more mechanical waves. 
     
     
         16 . The method of  claim 6 , further comprising applying a noise removal algorithm to said estimated one or more displacements. 
     
     
         17 . The method of  claim 16 , further comprising accumulating said estimated one or more displacements with time to track motion for an entire period of movement of the anatomical object. 
     
     
         18 . The method of  claim 17 , further comprising deriving strains in at least a portion of the anatomical object from said accumulated displacements. 
     
     
         19 . The method of  claim 18 , further comprising overlaying data representing at least one of said displacement and said strain onto said high frame rate composite images. 
     
     
         20 . The method of  claim 1 , wherein said synchronizing comprises leaving a first portion of each period of said periodic signal unchanged and interpolating a second portion of each period of said periodic signal to a total maximum length of the periods of the periodic signal. 
     
     
         21 . The method of  claim 20 , further comprising linearly interpolating corresponding images to a maximum length of an all sector image sequence. 
     
     
         22 . A computer program product comprising a computer usable medium having computer readable program code means embodied therein, said computer readable program code means in said computer program product comprising means for causing a computer to:
 cause an imaging device to acquire a series of images for each of a plurality of sectors over one or more periods of a periodic signal representing movement of at least a portion of an anatomical object, each of the sectors corresponding to a different portion of the anatomical object;   substantially simultaneously cause a signal acquisition device to acquire a period of the periodic signal in response to each periodic movement of the anatomical object, each of said series of images for each sector being acquired in response to said periodic signal; and   synchronize data for each of said plurality of sectors using said periodic signal.   
     
     
         23 . The computer program product of  claim 22 , said computer readable program code means in said computer program product further comprising means for causing a computer to:
 combine said data from said plurality of sectors to generate a series of composite images; and   display at least one of said series of composite images to a user.   
     
     
         24 . An imaging system, comprising:
 at least one computer;   at least one imaging device in communication with said at least one computer; and   a periodic signal acquisition device, in communication with said at least one computer and said at least one imaging device, wherein said at least one computer causes said at least one imaging device to acquire a series of images for each of a plurality of sectors over one or more periods of a periodic signal representing movement of at least a portion of an anatomical object, each of said plurality of sectors corresponding to a different portion of the anatomical object; and   wherein said at least one computer causes said periodic signal acquisition device to substantially simultaneously acquire a period of the periodic signal in response to each periodic movement of the anatomical object, each of said series of images for each sector being acquired in response to said periodic signal; and   wherein the computer:
 synchronizes data for each of said plurality of sectors using said periodic signal. 
   
     
     
         25 . The system of  claim 24 , wherein said at least one computer further combines said data from said plurality of sectors to generate a series of composite images. 
     
     
         26 . The system of  claim 25 , wherein said at least one computer further processes said series of composite images to calculate accumulated displacement as a function of time for at least a portion of said anatomical object. 
     
     
         27 . The system of  claim 26 , wherein said calculation of accumulated displacement includes estimating one or more displacements between consecutive time frames for one or more windows of said series of composite images. 
     
     
         28 . The system of  claim 26 , wherein said calculation of accumulated displacement further comprises applying a noise removal algorithm to said estimated one or more displacements. 
     
     
         29 . The system of  claim 26 , wherein said at least one computer further derives strain or strain rate in at least a portion of the anatomical object from said accumulated displacement. 
     
     
         30 . The system of  claim 29 , wherein said at least one computer further overlays data representing at least one of said displacement, said strain and said strain rate onto said series of composite images.