Medical-information processing apparatus and X-ray CT apparatus

1. A medical-information processing apparatus comprising processing circuitry configured to

acquire medical image data including a medical image that is obtained during imaging on a subject in a resting state in a time phase where a relationship between a volume of blood flow and a pressure in a blood vessel in a cardiac cycle of the subject indicates a proportional relationship,

extract a structure of the blood vessel of the subject, included in the medical image data,

obtain, in accordance with a relation between a volume of blood flow and a pressure in the blood vessel, a first index value, which is obtained based on a pressure in the blood vessel on an upstream side of a predetermined position within the blood vessel and a pressure at a time of zero flow volume, which indicates a pressure in the blood vessel in a case where the volume of blood flow within the blood vessel is zero, a second index value, which is obtained based on a pressure in the blood vessel on a downstream side of the predetermined position and the pressure at the time of zero flow volume, a third index value, which is obtained based on the pressure in the blood vessel on the upstream side of the predetermined position within the blood vessel and a pressure, which is lower than the pressure at the time of zero flow volume, and a fourth index value, which is obtained based on the pressure in the blood vessel on the downstream side of the predetermined position and the pressure, which is lower than the pressure at the time of zero flow volume, by applying fluid analysis to the structure of the blood vessel,

calculate a first pressure ratio that is a ratio of the first index value to the second index value, and a second pressure ratio that is a ratio of the third index value to the fourth index value, and

present the first pressure ratio and the second pressure ratio on a display.

2. The medical-information processing apparatus according to claim 1 , wherein the processing circuitry is configured to calculate the pressures in the blood vessel on the upstream side and on the downstream side and the pressure at the time of zero flow volume.

3. The medical-information processing apparatus according to claim 1 , wherein the processing circuitry is configured to

obtain the second index value and the first pressure ratio with regard to each of positions on the downstream side, and

present, on the display, the first pressure ratio at each of the positions on the downstream side together with the medical image data in a manner of being related to a corresponding position in the medical image data.

4. The medical-information processing apparatus according to claim 1 , wherein the processing circuitry is configured to

obtain a difference between the pressure in the blood vessel on the upstream side of the predetermined position within the blood vessel and the pressure at the time of zero flow volume as the first index value,

obtain a difference between the pressure in the blood vessel on the downstream side of the predetermined position within the blood vessel and the pressure at the time of zero flow volume as the second index value, and

calculate the first pressure ratio, which is the ratio of the first index value to the second index value.

5. The medical-information processing apparatus according to claim 1 , wherein the processing circuitry is configured to use at least any one of a blood pressure of a right atrium and zero as the pressure lower than the pressure at the time of zero flow volume to calculate, as the second pressure ratio, at least any one of a ratio of a pressure based on the pressure on the upstream side and the pressure of the right atrium to a pressure based on the pressure on the downstream side and the pressure of the right atrium and a ratio of the pressure on the upstream side to the pressure on the downstream side.

6. The medical-information processing apparatus according to claim 1 , wherein the processing circuitry is configured to present alarm information on the display in accordance with a value of the first pressure ratio and a value of the second pressure ratio.

7. The medical-information processing apparatus according to claim 6 , wherein the processing circuitry is configured to present the alarm information on the display in a case where a difference between the value of the first pressure ratio and the value of the second pressure ratio exceeds a predetermined threshold.

8. The medical-information processing apparatus according to claim 6 , wherein the processing circuitry is configured to present the alarm information on the display in a case where at least any one of the value of the first pressure ratio and the value of the second pressure ratio is equal to or less than a predetermined threshold.

9. The medical-information processing apparatus according to claim 1 , wherein the processing circuitry is configured to

generate a graph that indicates a relationship between the volume of blood flow and the pressure in the blood vessel in accordance with an analysis result of the fluid analysis, and

present the graph on the display.

10. The medical-information processing apparatus according to claim 9 , wherein the processing circuitry is configured to

calculate a tilt of the graph, and

present a value that indicates the tilt on the display.

11. The medical-information processing apparatus according to claim 9 , wherein the processing circuitry is configured to present information that corresponds to a time phase of image data, used for the fluid analysis, on the graph.

12. The medical-information processing apparatus according to claim 1 , wherein a time phase where the relationship between the volume of blood flow and the pressure in the blood vessel indicates a proportional relationship is a heart phase 70% to 99%.

13. An X-ray CT apparatus comprising processing circuitry configured to

acquire medical image data including a medical image obtained by conducting imaging on a subject in a resting state in a time phase where a relationship between a volume of blood flow and a pressure in a blood vessel in a cardiac cycle of the subject indicates a proportional relationship,

extract a structure of the blood vessel of the subject, included in the medical image data,

obtain, in accordance with a relation between a volume of blood flow and a pressure in the blood vessel, a first index value, which is obtained based on a pressure in the blood vessel on an upstream side of a predetermined position within the blood vessel and a pressure at a time of zero flow volume, which indicates a pressure in the blood vessel in a case where the volume of blood flow within the blood vessel is zero, a second index value, which is obtained based on a pressure in the blood vessel on a downstream side of the predetermined position and the pressure at the time of zero flow volume, a third index value, which is obtained based on the pressure in the blood vessel on the upstream side of the predetermined position within the blood vessel and a pressure, which is lower than the pressure at the time of zero flow volume, and a fourth index value, which is obtained based on the pressure in the blood vessel on the downstream side of the predetermined position and the pressure, which is lower than the pressure at the time of zero flow volume, by applying fluid analysis to the structure of the blood vessel,

calculate a first pressure ratio that is a ratio of the first index value to the second index value, and a second pressure ratio that is a ratio of the third index value to the fourth index value, and

present the first pressure ratio and the second pressure ratio on a display.

14. A medical-information processing apparatus comprising processing circuitry configured to

acquire medical image data including a medical image that is obtained during imaging on a subject in a state where a relationship between a volume of blood flow and a pressure in a blood vessel in a cardiac cycle of the subject is already known,

extract a structure of the blood vessel of the subject, included in the medical image data,

obtain, in accordance with a relation between a volume of blood flow and a pressure in the blood vessel, a first index value, which is obtained based on a pressure in the blood vessel on an upstream side of a predetermined position within the blood vessel and a pressure at a time of zero flow volume, which indicates a pressure in the blood vessel in a case where the volume of blood flow within the blood vessel is zero, a second index value, which is obtained based on a pressure in the blood vessel on a downstream side of the predetermined position and the pressure at the time of zero flow volume, a third index value, which is obtained based on the pressure in the blood vessel on the upstream side of the predetermined position within the blood vessel and a pressure, which is lower than the pressure at the time of zero flow volume, and a fourth index value, which is obtained based on the pressure in the blood vessel on the downstream side of the predetermined position and the pressure, which is lower than the pressure at the time of zero flow volume, by applying fluid analysis to the structure of the blood vessel,

calculate a first pressure ratio that is a ratio of the first index value to the second index value, and a second pressure ratio that is a ratio of the third index value to the fourth index value, and

present the first pressure ratio and the second pressure ratio on a display.

15. An X-ray CT apparatus comprising processing circuitry configured to

acquire medical image data including a medical image obtained by conducting imaging on a subject in a state where a relationship between a volume of blood flow and a pressure in a blood vessel in a cardiac cycle of the subject is already known,

extract a structure of the blood vessel of the subject, included in the medical image data,

obtain, in accordance with a relation between a volume of blood flow and a pressure in the blood vessel, a first index value, which is obtained based on a pressure in the blood vessel on an upstream side of a predetermined position within the blood vessel and a pressure at a time of zero flow volume, which indicates a pressure in the blood vessel in a case where the volume of blood flow within the blood vessel is zero, a second index value, which is obtained based on a pressure in the blood vessel on a downstream side of the predetermined position and the pressure at the time of zero flow volume, a third index value, which is obtained based on the pressure in the blood vessel on the upstream side of the predetermined position within the blood vessel and a pressure, which is lower than the pressure at the time of zero flow volume, and a fourth index value, which is obtained based on the pressure in the blood vessel on the downstream side of the predetermined position and the pressure, which is lower than the pressure at the time of zero flow volume, by applying fluid analysis to the structure of the blood vessel,

calculate a first pressure ratio that is a ratio of the first index value to the second index value, and a second pressure ratio that is a ratio of the third index value to the fourth index value, and

present the first pressure ratio and the second pressure ratio on a display.

16. A medical-information processing method performed by a medical-information processing apparatus, the medical-information processing method comprising:

acquiring medical image data including a medical image that is obtained during imaging on a subject in a resting state in a time phase where a relationship between a volume of blood flow and a pressure in a blood vessel in a cardiac cycle of the subject indicates a proportional relationship,

extracting a structure of the blood vessel of the subject, included in the medical image data,

obtaining, in accordance with a relation between a volume of blood flow and a pressure in the blood vessel, a first index value, which is obtained based on a pressure in the blood vessel on an upstream side of a predetermined position within the blood vessel and a pressure at a time of zero flow volume, which indicates a pressure in the blood vessel in a case where the volume of blood flow within the blood vessel is zero, a second index value, which is obtained based on a pressure in the blood vessel on a downstream side of the predetermined position and the pressure at the time of zero flow volume, a third index value, which is obtained based on the pressure in the blood vessel on the upstream side of the predetermined position within the blood vessel and a pressure, which is lower than the pressure at the time of zero flow volume, and a fourth index value, which is obtained based on the pressure in the blood vessel on the downstream side of the predetermined position and the pressure, which is lower than the pressure at the time of zero flow volume, by applying fluid analysis to the structure of the blood vessel,

calculating a first pressure ratio that is a ratio of the first index value to the second index value, and a second pressure ratio that is a ratio of the third index value to the fourth index value, and

presenting the first pressure ratio and the second pressure ratio on a display.

17. The medical-information processing method according to claim 16 , wherein calculating the pressures in the blood vessel on the upstream side and on the downstream side and the pressure at the time of zero flow volume.

18. The medical-information processing method according to claim 16 , wherein

obtaining the second index value and the first pressure ratio with regard to each of positions on the downstream side, and

presenting, on the display, the first pressure ratio at each of the positions on the downstream side together with the medical image data in a manner of being related to a corresponding position in the medical image data.

19. The medical-information processing method according to claim 16 , wherein

obtaining a difference between the pressure in the blood vessel on the upstream side of the predetermined position within the blood vessel and the pressure at the time of zero flow volume as the first index value,

obtaining a difference between the pressure in the blood vessel on the downstream side of the predetermined position within the blood vessel and the pressure at the time of zero flow volume as the second index value, and

calculating the first pressure ratio, which is the ratio of the first index value to the second index value.

20. The medical-information processing method according to claim 16 , wherein using at least any one of a blood pressure of a right atrium and zero as the pressure lower than the pressure at the time of zero flow volume to calculate, as the second pressure ratio, at least any one of a ratio of a pressure based on the pressure on the upstream side and the pressure of the right atrium to a pressure based on the pressure on the downstream side and the pressure of the right atrium and a ratio of the pressure on the upstream side to the pressure on the downstream side.

21. The medical-information processing method according to claim 16 , wherein presenting alarm information on the display in accordance with a value of the first pressure ratio and a value of the second pressure ratio.

22. The medical-information processing method according to claim 20 , wherein presenting the alarm information on the display in a case where a difference between the value of the first pressure ratio and the value of the second pressure ratio exceeds a predetermined threshold.

23. The medical-information processing method according to claim 21 , wherein presenting the alarm information on the display in a case where at least any one of the value of the first pressure ratio and the value of the second pressure ratio is equal to or less than a predetermined threshold.

24. The medical-information processing method according to claim 16 , wherein

generating a graph that indicates a relationship between the volume of blood flow and the pressure in the blood vessel in accordance with an analysis result of the fluid analysis, and

presenting the graph on the display.

25. The medical-information processing method according to claim 24 , wherein

calculating a tilt of the graph, and

presenting a value that indicates the tilt on the display.

26. The medical-information processing method according to claim 24 , wherein presenting information that corresponds to a time phase of image data, used for the fluid analysis, on the graph.

27. The medical-information processing method according to claim 16 , wherein a time phase where the relationship between the volume of blood flow and the pressure in the blood vessel indicates a proportional relationship is a heart phase 70% to 99%.

28. A medical-information processing system comprising processing circuitry configured to

acquire medical image data including a medical image that is obtained during imaging on a subject in a resting state in a time phase where a relationship between a volume of blood flow and a pressure in a blood vessel in a cardiac cycle of the subject indicates a proportional relationship,

extract a structure of the blood vessel of the subject, included in the medical image data,

obtain, in accordance with a relation between a volume of blood flow and a pressure in the blood vessel, a first index value, which is obtained based on a pressure in the blood vessel on an upstream side of a predetermined position within the blood vessel and a pressure at a time of zero flow volume, which indicates a pressure in the blood vessel in a case where the volume of blood flow within the blood vessel is zero, a second index value, which is obtained based on a pressure in the blood vessel on a downstream side of the predetermined position and the pressure at the time of zero flow volume, a third index value, which is obtained based on the pressure in the blood vessel on the upstream side of the predetermined position within the blood vessel and a pressure, which is lower than the pressure at the time of zero flow volume, and a fourth index value, which is obtained based on the pressure in the blood vessel on the downstream side of the predetermined position and the pressure, which is lower than the pressure at the time of zero flow volume, by applying fluid analysis to the structure of the blood vessel,

calculate a first pressure ratio that is a ratio of the first index value to the second index value, and a second pressure ratio that is a ratio of the third index value to the fourth index value, and

present the first pressure ratio and the second pressure ratio on a display.

29. The medical-information processing system according to claim 28 , wherein the processing circuitry is configured to calculate the pressures in the blood vessel on the upstream side and on the downstream side and the pressure at the time of zero flow volume.

30. The medical-information processing system according to claim 28 , wherein the processing circuitry is configured to

obtain the second index value and the first pressure ratio with regard to each of positions on the downstream side, and

present, on the display, the first pressure ratio at each of the positions on the downstream side together with the medical image data in a manner of being related to a corresponding position in the medical image data.

31. The medical-information processing system according to claim 28 , wherein the processing circuitry is configured to

obtain a difference between the pressure in the blood vessel on the upstream side of the predetermined position within the blood vessel and the pressure at the time of zero flow volume as the first index value,

obtain a difference between the pressure in the blood vessel on the downstream side of the predetermined position within the blood vessel and the pressure at the time of zero flow volume as the second index value, and

calculate the first pressure ratio, which is the ratio of the first index value to the second index value.

32. The medical-information processing system according to claim 28 , wherein the processing circuitry is configured to use at least any one of a blood pressure of a right atrium and zero as the pressure lower than the pressure at the time of zero flow volume to calculate, as the second pressure ratio, at least any one of a ratio of a pressure based on the pressure on the upstream side and the pressure of the right atrium to a pressure based on the pressure on the downstream side and the pressure of the right atrium and a ratio of the pressure on the upstream side to the pressure on the downstream side.

33. The medical-information processing system according to claim 28 , wherein the processing circuitry is configured to present alarm information on the display in accordance with a value of the first pressure ratio and a value of the second pressure ratio.

34. The medical-information processing system according to claim 33 , wherein the processing circuitry is configured to present the alarm information on the display in a case where a difference between the value of the first pressure ratio and the value of the second pressure ratio exceeds a predetermined threshold.

35. The medical-information processing system according to claim 33 , wherein the processing circuitry is configured to present the alarm information on the display in a case where at least any one of the value of the first pressure ratio and the value of the second pressure ratio is equal to or less than a predetermined threshold.

36. The medical-information processing system according to claim 28 , wherein the processing circuitry is configured to

generate a graph that indicates a relationship between the volume of blood flow and the pressure in the blood vessel in accordance with an analysis result of the fluid analysis, and

present the graph on the display.

37. The medical-information processing system according to claim 36 , wherein the processing circuitry is configured to

calculate a tilt of the graph, and

present a value that indicates the tilt on the display.

38. The medical-information processing system according to claim 36 , wherein the processing circuitry is configured to present information that corresponds to a time phase of image data, used for the fluid analysis, on the graph.

39. The medical-information processing system according to claim 28 , wherein a time phase where the relationship between the volume of blood flow and the pressure in the blood vessel indicates a proportional relationship is a heart phase 70% to 99%.