Photoacoustic measurement apparatus and photoacoustic measurement system

1. A photoacoustic measurement apparatus, comprising:

a receiving circuit that receives a detection signal of a photoacoustic wave, which is generated in a subject due to emission of measurement light to the subject, in each of at least an avascularized condition in which the subject is avascularized and a non-avascularized condition in which the subject is not avascularized;

a processor configured to

generate a photoacoustic image for each of the avascularized condition and the non-avascularized condition based on the detection signal of the photoacoustic wave; and

generate blood flow information based on a signal value of each of the photoacoustic images in a region of interest set in the photoacoustic images,

wherein the processor is configured to calculate a total value or an average value of the signal value in the region of interest for each time point or time frame, the each time point or the time frame corresponding to one of the photoacoustic images, and

wherein the processor further generates, as the blood flow information, a score value based on a difference between the total value or the average value of the signal value in the region of interest in the avascularized condition and the total value or the average value of the signal value in the region of interest in the non-avascularized condition.

2. The photoacoustic measurement apparatus according to claim 1 , further comprising:

a tourniquet capable of changing a cuff pressure in order to bring the subject into the avascularized condition and the non-avascularized condition.

3. The photoacoustic measurement apparatus according to claim 2 , the processor further configured to:

control a cuff pressure of the tourniquet.

4. The photoacoustic measurement apparatus according to claim 1 ,

wherein the processor binarizes the signal value by setting the signal value to a first value when the signal value is equal to or greater than a first threshold value and equal to or less than a second threshold value larger than the first threshold value and setting the signal value to a second value different from the first value when the signal value is less than the first threshold value or greater than the second threshold value, and generates the blood flow information based on the binarized signal value.

5. The photoacoustic measurement apparatus according to claim 2 ,

wherein the processor binarizes the signal value by setting the signal value to a first value when the signal value is equal to or greater than a first threshold value and equal to or less than a second threshold value larger than the first threshold value and setting the signal value to a second value different from the first value when the signal value is less than the first threshold value or greater than the second threshold value, and generates the blood flow information based on the binarized signal value.

6. The photoacoustic measurement apparatus according to claim 1 ,

wherein the processor further generates a graph showing a relationship between the blood flow information and time.

7. The photoacoustic measurement apparatus according to claim 1 ,

wherein the receiving circuit further receives a detection signal of a reflected acoustic wave with respect to an acoustic wave transmitted to the subject,

the processor further configured to

generate a reflected acoustic wave image based on the detection signal of the reflected acoustic wave; and

track a position of the region of interest using the reflected acoustic wave image.

8. The photoacoustic measurement apparatus according to claim 1 ,

wherein the processor generates, as blood flow information, a total value or an average value of the signal value in the region of interest.

9. The photoacoustic measurement apparatus according to claim 1 , further comprising:

a pressure measurement sensor configured to measure a cuff pressure of the subject,

wherein the processor further generates a graph showing a relationship between the blood flow information and the avascularization pressure.

10. The photoacoustic measurement apparatus according to claim 1 ,

wherein the processor calculates a total value or an average value of the signal value in the region of interest in a certain period, and generates, as the blood flow information, a score value based on a difference between a minimum value and a maximum value of the total value or the average value in the certain period, repeatedly.

11. The photoacoustic measurement apparatus according to claim 1 ,

wherein the processor is configured to calculate a total value or an average value of the signal value in the region of interest for each time point or time frame,

wherein, in a case where the subject is changed from the avascularized condition to the non-avascularized condition, the processor further generates, as the blood flow information, a score value based on a time change rate of the total value or the average value of the signal value in the region of interest.

12. The photoacoustic measurement apparatus according to claim 1 ,

wherein the processor is configured to calculate a total value or an average value of the signal value in the region of interest for each time point or time frame,

wherein, in a case where the subject is changed from the avascularized condition to the non-avascularized condition, the processor further generates, as the blood flow information, a score value based on the total value or the average value of the signal value in the region of interest after a certain time has passed from a reference time.

13. The photoacoustic measurement apparatus according to claim 1 ,

wherein the processor is configured to calculate a total value or an average value of the signal value in the region of interest for each time point or time frame,

wherein, in a case where the subject is changed from the avascularized condition to the non-avascularized condition, the processor further generates, as the blood flow information, a score value based on a time from a reference time to a time at which the total value or the average value of the signal value in the region of interest reaches a certain level.

14. The photoacoustic measurement apparatus according to claim 1 ,

wherein the processor further generates a blood flow information image based on the blood flow information.

15. The photoacoustic measurement apparatus according to claim 14 ,

wherein, in a case where a plurality of the regions of interest are set, the blood flow information is generated for each of the plurality of regions of interest, and the blood flow information image is a space map image for displaying blood flow information of each region of interest in the region of interest.

16. The photoacoustic measurement apparatus according to claim 15 ,

wherein, in the blood flow information image, each region of interest is displayed with a brightness corresponding to the blood flow information.

17. The photoacoustic measurement apparatus according to claim 15 ,

wherein the processor sets a display color of each region of interest in the blood flow information image to a different display color in a case where blood flow information at a first time is larger than blood flow information at a second time earlier than the first time and a case where the blood flow information at the first time is smaller than the blood flow information at the second time.

18. The photoacoustic measurement apparatus according to claim 1 ,

wherein a plurality of the regions of interest are set in a grid form.

19. A photoacoustic measurement system, comprising:

a light source that emits measurement light; and

the photoacoustic measurement apparatus according to claim 1 .

20. A photoacoustic measurement apparatus, comprising:

a receiving circuit that receives a detection signal of a photoacoustic wave, which is generated in a subject due to emission of measurement light to the subject, in each of at least an avascularized condition in which the subject is avascularized and a non-avascularized condition in which the subject is not avascularized;

a processor configured to

generate a photoacoustic image for each of the avascularized condition and the non-avascularized condition based on the detection signal of the photoacoustic wave; and

generate blood flow information based on a signal value of each of the photoacoustic images in a region of interest set in the photoacoustic images,

wherein the processor repeatedly calculates a total value or an average value of the signal value in the region of interest in a certain period, the certain period corresponding to one of the photoacoustic images and generates, as the blood flow information, a score value based on a difference between a minimum value and a maximum value of the total values or the average values in the certain period.