Ultrasound image reconstruction method, device therefor, and ultrasound diagnostic device

Abstract

In order to acquire high resolution ultrasound images while maintaining an appropriate frame rate in ultrasound diagnostic devices, the disclosed method generates high resolution ultrasound images by performing image reconstruction on the basis of multiple ultrasound frame images captured along a time series and the magnitudes of positional shifts, or forms high resolution ultrasound images by performing image reconstruction on the basis of multiple ultrasound frame images acquired by controlling the ultrasound probe and varying scan orientation or scan focal length frame by frame.

1 . An ultrasound image reconstruction method for reconstructing an ultrasound image of a sample by processing ultrasound images acquired from a signal generated by scanning the sample with an ultrasound signal by use of an ultrasound probe and receiving a reflected wave from the sample, comprising the steps of:
 extracting an ultrasound frame image at a certain time point and an ultrasound frame image at a time point before the certain time point from a series of ultrasound frame images constituting the ultrasound images acquired by the imaging;   calculating magnitudes of positional shifts between the extracted ultrasound frame image at the certain time point and the extracted ultrasound frame image at the time point before the certain time point; and   reconstructing a composite ultrasound image for one frame by compensating for the positional shifts between the extracted ultrasound frame image at the certain time point and the extracted ultrasound frame image at the time point before the certain time point by use of information on the calculated magnitudes of positional shifts and merging the extracted ultrasound frame image at the certain time point and the extracted ultrasound frame image at the time point before the certain time point after undergoing the positional shift compensation together.   
     
     
         2 . The ultrasound image reconstruction method according to  claim 1 , wherein the ultrasound frame image at the certain time point and the ultrasound frame image at the time point before the certain time point are ultrasound images acquired in states differing in the scan condition for the scanning of the sample with the ultrasound signal by use of the ultrasound probe. 
     
     
         3 . The ultrasound image reconstruction method according to  claim 1 , wherein the ultrasound frame image at the certain time point and the ultrasound frame image at the time point before the certain time point are ultrasound images acquired by performing the scan in states differing in at least one of the scan orientation and the scan focal length for the scanning of the sample with the ultrasound signal by use of the ultrasound probe. 
     
     
         4 . The ultrasound image reconstruction method according to  claim 1 , wherein the merging of the ultrasound frame image at the certain time point and the ultrasound frame image at the time point before the certain time point after undergoing the positional shift compensation is executed by splitting each of the ultrasound frame image at the certain time point and the ultrasound frame image at the time point before the certain time point into local regions, setting a weighting parameter varying from region to region for each of the locally split regions, and reflecting each region into the image reconstruction process so that a region having a greater weight is reflected more into the result of the image reconstruction process. 
     
     
         5 . The ultrasound image reconstruction method according to  claim 1 , wherein a composite ultrasound image for one frame at a time point between the certain time point and the time point before the certain time point is estimated and generated by merging the extracted ultrasound frame image at the certain time point and the extracted ultrasound frame image at the time point before the certain time point after undergoing the positional shift compensation together. 
     
     
         6 . The ultrasound image reconstruction method according to  claim 1 , wherein:
 the sample is one that moves periodically, and   the images acquired by the imaging are ultrasound images acquired by scanning the sample for a time longer than or equal to twice the cycle of the periodical movement of the sample under scan conditions varying cycle by cycle, and   the extraction of the ultrasound frame image at the certain time point and the ultrasound frame image at the time point before the certain time point is extraction of the ultrasound frame image at the certain time point and an ultrasound frame image at a time point one cycle before the certain time point.   
     
     
         7 . An ultrasound image reconstruction device comprising:
 reception circuit means which receives a reflected wave signal generated by scanning a sample with an ultrasound probe and receiving a reflected wave from the sample;   image generating means which generates ultrasound images from the reflected wave signal received by the reception circuit means;   image processing means which executes a reconstruction process to the ultrasound images generated by the image generating means; and   display means which displays an ultrasound image obtained by the reconstruction process by the image processing means on a screen,   wherein the image processing means extracts an ultrasound frame image at a certain time point and an ultrasound frame image at a time point before the certain time point from a series of ultrasound frame images constituting the ultrasound images generated by the image generating means, calculates magnitudes of positional shifts between the extracted ultrasound frame image at the certain time point and the extracted ultrasound frame image at the time point before the certain time point, and reconstructs a composite ultrasound image for one frame by compensating for the positional shifts between the extracted ultrasound frame image at the certain time point and the extracted ultrasound frame image at the time point before the certain time point by use of information on the calculated magnitudes of positional shifts and merging the extracted ultrasound frame image at the certain time point and the extracted ultrasound frame image at the time point before the certain time point after undergoing the positional shift compensation together.   
     
     
         8 . The ultrasound image reconstruction device according to  claim 7 , wherein the ultrasound frame image at the certain time point and the ultrasound frame image at the time point before the certain time point to be processed by the image processing means are ultrasound images acquired in states differing in the scan condition for the scanning of the sample with the ultrasound signal by use of the ultrasound probe. 
     
     
         9 . The ultrasound image reconstruction device according to  claim 7 , wherein the ultrasound frame image at the certain time point and the ultrasound frame image at the time point before the certain time point to be processed by the image processing means are ultrasound images acquired by performing the scan in states differing in at least one of the scan orientation and the scan focal length for the scanning of the sample with the ultrasound signal by use of the ultrasound probe. 
     
     
         10 . The ultrasound image reconstruction device according to  claim 7 , wherein the image processing means executes the merging of the ultrasound frame image at the certain time point and the ultrasound frame image at the time point before the certain time point after undergoing the positional shift compensation by splitting each of the ultrasound frame image at the certain time point and the ultrasound frame image at the time point before the certain time point into local regions, setting a weighting parameter varying from region to region for each of the locally split regions, and reflecting each region into the image reconstruction process so that a region having a greater weight is reflected more into the result of the image reconstruction process. 
     
     
         11 . The ultrasound image reconstruction device according to  claim 7 , wherein the image processing means estimates and generates a composite ultrasound image for one frame at a time point between the certain time point and the time point before the certain time point by merging the extracted ultrasound frame image at the certain time point and the extracted ultrasound frame image at the time point before the certain time point after undergoing the positional shift compensation together. 
     
     
         12 . The ultrasound image reconstruction device according to  claim 7 , wherein:
 the sample is one that moves periodically, and   the images acquired by the imaging by use of the ultrasound probe are ultrasound images acquired by scanning the sample for a time longer than or equal to twice the cycle of the periodical movement of the sample under scan conditions varying cycle by cycle, and   the extraction of the ultrasound frame image at the certain time point and the ultrasound frame image at the time point before the certain time point performed by the image processing means is extraction of the ultrasound frame image at the certain time point and an ultrasound frame image at a time point one cycle before the certain time point.   
     
     
         13 . An ultrasound diagnostic device comprising:
 an ultrasound probe which scans a sample with an ultrasound signal and receives a reflected wave from the sample; and   an ultrasound image processing unit which generates ultrasound images by processing the reflected wave signal received by the ultrasound probe, the ultrasound image processing unit including image generating means which generates ultrasound images from the reflected wave signal and image processing means which executes a reconstruction process to the ultrasound image generated by the image generating means,   wherein the image processing means extracts an ultrasound frame image at a certain time point and an ultrasound frame image at a time point before the certain time point from a series of ultrasound frame images constituting the ultrasound images generated by the image generating means, calculates magnitudes of positional shifts between the extracted ultrasound frame image at the certain time point and the extracted ultrasound frame image at the time point before the certain time point, and reconstructs a composite ultrasound image for one frame by compensating for the positional shifts between the extracted ultrasound frame image at the certain time point and the extracted ultrasound frame image at the time point before the certain time point by use of information on the calculated magnitudes of positional shifts and merging the extracted ultrasound frame image at the certain time point and the extracted ultrasound frame image at the time point before the certain time point after undergoing the positional shift compensation together.   
     
     
         14 . The ultrasound diagnostic device according to  claim 13 , wherein the ultrasound frame image at the certain time point and the ultrasound frame image at the time point before the certain time point to be processed by the image processing means are ultrasound images acquired in states differing in the scan condition for the scanning of the sample with the ultrasound signal by use of the ultrasound probe. 
     
     
         15 . The ultrasound diagnostic device according to  claim 13 , wherein the ultrasound frame image at the certain time point and the ultrasound frame image at the time point before the certain time point to be processed by the image processing means are ultrasound images acquired by performing the scan in states differing in at least one of the scan orientation and the scan focal length for the scanning of the sample with the ultrasound signal by use of the ultrasound probe. 
     
     
         16 . The ultrasound diagnostic device according to  claim 13 , wherein the image processing means executes the merging of the ultrasound frame image at the certain time point and the ultrasound frame image at the time point before the certain time point after undergoing the positional shift compensation by splitting each of the ultrasound frame image at the certain time point and the ultrasound frame image at the time point before the certain time point into local regions, setting a weighting parameter varying from region to region for each of the locally split regions, and reflecting each region into the image reconstruction process so that a region having a greater weight is reflected more into the result of the image reconstruction process. 
     
     
         17 . The ultrasound diagnostic device according to  claim 13 , wherein the image processing means estimates and generates a composite ultrasound image for one frame at a time point between the certain time point and the time point before the certain time point by merging the extracted ultrasound frame image at the certain time point and the extracted ultrasound frame image at the time point before the certain time point after undergoing the positional shift compensation together. 
     
     
         18 . The ultrasound diagnostic device according to  claim 13 , wherein:
 the sample is one that moves periodically, and   the images acquired by the imaging by use of the ultrasound probe are ultrasound images acquired by scanning the sample for a time longer than or equal to twice the cycle of the periodical movement of the sample under scan conditions varying cycle by cycle, and   the extraction of the ultrasound frame image at the certain time point and the ultrasound frame image at the time point before the certain time point performed by the image processing means is extraction of the ultrasound frame image at the certain time point and an ultrasound frame image at a time point one cycle before the certain time point.