Medical image processing device and computer program product

1 . A medical image processing device, comprising:

processing circuitry configured to:

sequentially acquire ultrasound images of a subject, and detect, from each acquired ultrasound image, individual microbubbles included in a contrast medium administered to a subject,

calculate a density of microbubbles in a first region of interest (ROI) in each ultrasound image by dividing a number of detected microbubbles in the first ROI by an area of the first ROI,

calculate a density of microbubbles in a second ROI that is located inside the first ROI, and completely surrounded by the first ROI, by dividing a number of detected microbubbles in the second ROI by an area of the second ROI, and

output information, based on the plurality of sequentially acquired ultrasound images, that indicates temporal changes in the microbubble densities in the first and second ROIs and allows identification of which ROI has a higher or lower microbubble density over time.

2 . The medical image processing device according to claim 1 , wherein the processing circuitry is further configured to calculate, as the information, values of the density of microbubbles in the first ROI, the density of the microbubbles in the second ROI, and a density ratio between the density of microbubbles in the first ROI and the density of the microbubbles in the second ROI in a predetermined time phase, or a cumulative value or an average value of the values in a predetermined section.

3 . The medical image processing device according to claim 2 , wherein the processing circuitry is further configured to calculate the cumulative value or the average value in the predetermined section while eliminating double-counting of an identical bubble.

4 . The medical image processing device according to claim 1 , wherein the processing circuitry is further configured to:

calculate a motion vector of the microbubbles by tracking a position of the microbubbles in each of a plurality of ultrasound images arranged in time series, and

calculate an inflow/outflow ratio of the microbubbles in at least one of the first ROI and the second ROI based on the calculated motion vector.

5 . The medical image processing device according to claim 4 , wherein the processing circuitry is further configured to calculate, as the inflow/outflow ratio, at least one of:

a value obtained by dividing a number of inflow bubbles by a number of inflow/outflow bubbles, a value obtained by dividing a number of outflow bubbles by the number of inflow/outflow bubbles,

a value obtained by dividing the number of inflow bubbles by the number of outflow bubbles, and

a value obtained by dividing the number of outflow bubbles by the number of inflow bubbles.

6 . The medical image processing device according to claim 4 , wherein the processing circuitry is further configured to calculate, as the inflow/outflow ratio, a value in a predetermined time phase, or a cumulative value or an average value in a predetermined section.

7 . The medical image processing device according to claim 6 , wherein the processing circuitry is further configured to calculate the cumulative value or the average value in the predetermined section while eliminating double-counting of an identical bubble.

8 . The medical image processing device according to claim 4 , wherein the processing circuitry is further configured to display information indicating temporal changes in the inflow/outflow ratio.

9 . The medical image processing device according to claim 1 , wherein the medical image processing device is an ultrasonic diagnostic device.

10 . The medical image processing device according to claim 1 , wherein the first region of interest is an annular region.

11 . A medical image processing device, comprising:

processing circuitry configured to:

sequentially acquire ultrasound images of a subject,

detect, from the acquired ultrasound images, individual microbubbles of a contrast medium administered to the subject,

set a region of interest in each ultrasound image,

calculate a motion vector of the contrast medium by tracking a position of the contrast medium in each of the ultrasound images arranged in time series,

calculate, based on the calculated motion vector, an angle representing a moving direction of the contrast medium with respect to a reference position for each contrast medium bubble within the region of interest,

identify an inflow bubble and an outflow bubble among the contrast medium based on the calculated angle and a set angle range, and

calculate an inflow/outflow ratio of the contrast medium in the region of interest based on a number of identified inflow bubbles and a number of identified outflow bubbles.

12 . The medical image processing device according to claim 11 , wherein the processing circuitry is further configured to calculate, as the inflow/outflow ratio, at least one of:

a value obtained by dividing a number of inflow bubbles by a number of inflow/outflow bubbles,

a value obtained by dividing a number of outflow bubbles by the number of inflow/outflow bubbles,

a value obtained by dividing the number of inflow bubbles by the number of outflow bubbles, and

a value obtained by dividing the number of outflow bubbles by the number of inflow bubbles.

13 . The medical image processing device according to claim 11 , wherein the processing circuitry is further configured to calculate, as the inflow/outflow ratio, a value in a predetermined time phase, or a cumulative value or an average value in a predetermined section.

14 . The medical image processing device according to claim 13 , wherein the processing circuitry is further configured to calculate the cumulative value or the average value in the predetermined section while eliminating double-counting of an identical bubble.

15 . The medical image processing device according to claim 11 , wherein the processing circuitry is further configured to display information indicating temporal changes in the inflow/outflow ratio.

16 . The medical image processing device according to claim 11 , wherein the medical image processing device is an ultrasonic diagnostic device.

17 . A computer program product having a non-transitory computer readable recording medium including programmed instructions, wherein the instructions, when executed by a computer, cause the computer to perform:

sequentially acquiring ultrasound images of a subject, and detecting, from each acquired ultrasound image, individual microbubbles included in a contrast medium administered to a subject;

calculating a density of microbubbles in a first region of interest (ROI) in each ultrasound image by dividing a number of detected microbubbles in the first ROI by an area of the first ROI,

calculating a density of microbubbles in a second ROI that is located inside the first ROI and completely surrounded by the first ROI, by dividing a number of detected microbubbles in the second ROI by an area of the second ROI, and

outputting information, based on the plurality of sequentially acquired ultrasound images, that indicates temporal changes in the microbubble densities in the first and second ROIs and allows identification of which ROI has a higher or lower microbubble density over time.

18 . A computer program product having a non-transitory computer readable recording medium including programmed instructions, wherein the instructions, when executed by a computer, cause the computer to perform:

sequentially acquiring ultrasound images of a subject:

detecting, from the acquired ultrasound images, individual microbubbles of a contrast medium administered to the subject from a plurality of ultrasound images arranged in time series, the contrast medium including that includes an amount of microbubbles that do not overlap with each other;

setting a region of interest in each ultrasound image;

calculating a motion vector of the contrast medium by tracking a position of the contrast medium in each of the ultrasound images arranged in time series;

calculating, based on the calculated motion vector, an angle representing a moving direction of the contrast medium with respect to a reference position for each contrast medium bubble within the region of interest;

identifying an inflow bubble and an outflow bubble among the contrast medium based on the calculated angle and a set angle range; and

calculating an inflow/outflow ratio of the contrast medium in the based on a number of identified inflow bubbles and a number of identified outflow bubbles.