MEDICAL IMAGE PROCESSING APPARATUS AND MEDICAL IMAGE PROCESSING METHOD

1 . A medical image processing apparatus, comprising:

processing circuitry configured to:

acquire medical images of a plurality of time phases of a subject tissue of a subject;

generate a vascular territory image showing a plurality of vascular territories included in the subject tissue based on the medical images of multiple time phases;

set a region of interest in the subject tissue;

set at least two regions out of the vascular territories and an ischemia area in the region of interest based on the vascular territory image;

calculate a ratio of each of the at least two regions to the region of interest; and

output information about the ratio.

2 . The medical image processing apparatus according to claim 1 , wherein

the processing circuitry is further configured to calculate a volume ratio of each of the at least two regions to the region of interest, as the ratio of each of the at least two regions to the region of interest.

3 . The medical image processing apparatus according to claim 1 , wherein

the subject tissue is brain, and

the processing circuitry is further configured to set the region of interest in a hemisphere including the ischemia area out of two hemispheres of the brain in the vascular territory image.

4 . The medical image processing apparatus according to claim 3 , wherein

the processing circuitry is further configured to identify an entire territory of a hemisphere on an opposite side to the hemisphere including the ischemia area by using at least one of the medical images of multiple time phases, and set an inverted territory of the identified territory relative to a median plane of the brain as the region of interest.

5 . The medical image processing apparatus according to claim 3 , wherein

the processing circuitry is further configured to detect a position of the ischemia area in the hemisphere including the ischemia area by using the vascular territory image, identify a vascular territory including a position corresponding to the position of the ischemia area in a hemisphere on an opposite side to the hemisphere including the ischemia area, and set an inverted territory of the identified vascular territory relative to a median plane of the brain as the region of interest.

6 . The medical image processing apparatus according to claim 3 , wherein

the processing circuitry is further configured to

acquire a healthy vascular-territory image showing a vascular territory in a healthy condition, and

detect a position of the ischemia area in the hemisphere including the ischemia area by using the vascular territory image, identify a vascular territory including a position of the ischemia area detected by the vascular territory image by using the healthy vascular-territory image, and set a region in which the identified vascular territory is mapped in the vascular territory image as the region of interest.

7 . The medical image processing apparatus according to claim 3 , wherein

the processing circuitry is further configured to

acquire a perfusion image of the subject, and

identify a low perfusion area in the hemisphere including the ischemia area by using the perfusion image, and set a region in which the identified low perfusion area is mapped in the vascular territory image as the region of interest.

8 . The medical image processing apparatus according to claim 3 , wherein

the processing circuitry is further configured to calculate a volume ratio of each of the at least two regions to the region of interest as a first volume ratio, calculate a volume ratio of each of the at least two regions included in the hemisphere on the opposite side to the hemisphere including the ischemia area to the entire territory of the hemisphere on the opposite side as a second volume ratio, and calculate a difference between the first volume ratio and the second volume ratio for each corresponding regions.

9 . The medical image processing apparatus according to claim 3 , wherein

the vascular territories are a middle cerebral artery territory, an anterior cerebral artery territory, and a posterior cerebral artery territory.

10 . The medical image processing apparatus according to claim 1 , wherein

the processing circuitry is further configured to classify the at least two regions into a plurality of blood flow patterns including a anterograde perfusion area, a retrograde perfusion area, and an ischemia area, and calculate the ratio for each of the blood flow patterns.

11 . The medical image processing apparatus according to claim 10 , wherein

the processing circuitry is further configured to output the vascular territory image showing a region of at least one blood flow pattern out of the blood flow patterns.

12 . The medical image processing apparatus according to claim 1 , wherein

the processing circuitry is further configured to determine a treatment to be adopted to the subject tissue based on the ratio of each of the at least two regions to the region of interest.

13 . A medical image processing method, comprising:

acquiring medical images of a plurality of time phases of a subject tissue of a subject;

generating a vascular territory image showing a plurality of vascular territories included in the subject tissue based on the medical images of multiple time phases;

setting a region of interest in the subject tissue;

setting at least two regions out of a plurality of regions including the vascular territories and an ischemia area in the region of interest based on the vascular territory image;

calculating a ratio of each of the at least two regions to the region of interest; and

outputting information about the ratio.