Medical image processing apparatus, medical image processing method, and program

1 . A medical image processing apparatus comprising:

a processor; and

a memory that stores a program to be executed by the processor,

wherein the processor is configured to: by executing a command of the program,

acquire a three-dimensional medical image,

receive an input of information indicating a lesion region included in the medical image,

determine, from the medical image, a measurement reference surface serving as a measurement reference for lesion evaluation,

three-dimensionally measure a distance between the lesion region and the measurement reference surface,

in response to a first measurement reference surface outside a lesion region being determined as the measurement reference surface, display a measurement result including information indicating a closest distance between the lesion region and the measurement reference surface together with the medical image; and

in response to a second measurement reference surface intersecting with the lesion region being determined as the measurement reference surface, display another measurement result including information indicating a farthest distance between the lesion region and the measurement reference surface.

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

wherein the processor further displays information indicating a closest portion between the first measurement reference surface and the lesion region in response to the first measurement reference surface being determined as the measurement reference surface.

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

wherein the processor further displays information indicating a farthest portion between a portion of the lesion region that invades beyond the second measurement reference surface and the second measurement reference surface in response to the second measurement reference surface being determined as the measurement reference surface.

4 . The medical image processing apparatus according to claim 1 ,

wherein the processor is configured to:

determine, from the lesion region, a lesion-region-side measurement reference region serving as a lesion-region-side reference of the measurement for the lesion evaluation, and

measure a distance between the lesion-region-side measurement reference region and the measurement reference surface.

5 . The medical image processing apparatus according to claim 4 ,

wherein the lesion-region-side measurement reference region is a partial region of the lesion region.

6 . The medical image processing apparatus according to claim 4 ,

wherein the lesion-region-side measurement reference region is a region corresponding to at least a portion of an outer circumference surface of the lesion region.

7 . The medical image processing apparatus according to claim 4 ,

wherein the processor is configured to:

display, in a case where a distance between the first measurement reference surface and the lesion-region-side measurement reference region is shorter than a first threshold value, information indicating that the distance is shorter than the first threshold value together with the medical image.

8 . The medical image processing apparatus according to claim 4 ,

wherein the processor is configured to:

display, for a portion at which a distance between the second measurement reference surface and the lesion-region-side measurement reference region is equal to or longer than a second threshold value, information indicating that the distance is equal to or longer than the second threshold value together with the medical image.

9 . The medical image processing apparatus according to claim 1 ,

wherein the processor is configured to:

determine, from a region that is included in the lesion region and is inside the first measurement reference surface and outside the second measurement reference surface, a lesion-region-side measurement reference region serving as a lesion-region-side reference of the measurement for the lesion evaluation, and

measure a distance between at least one of the first measurement reference surface or the second measurement reference surface and the lesion-region-side measurement reference region.

10 . The medical image processing apparatus according to claim 9 ,

wherein the processor is configured to:

measure a distance between the first measurement reference surface and the lesion-region-side measurement reference region, and

display the measurement result including information indicating the closest distance between the first measurement reference surface and the lesion-region-side measurement reference region together with the medical image.

11 . The medical image processing apparatus according to claim 1 ,

wherein each of the measurement result and the another measurement result includes a numerical value indicating a distance, a color map representing the distance using a color, or information indicating a determination result as to whether or not the distance exceeds a threshold value.

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

wherein the processor is configured to:

perform lesion region extraction processing of automatically extracting the lesion region from the medical image, and

acquire the information indicating the lesion region.

13 . The medical image processing apparatus according to claim 12 ,

wherein the lesion region extraction processing includes processing of extracting the lesion region by performing image segmentation using a model which is trained by machine learning.

14 . The medical image processing apparatus according to claim 1 ,

wherein the processor is configured to:

receive an input of the information indicating the lesion region which is designated by using an input device.

15 . The medical image processing apparatus according to claim 1 ,

wherein the measurement reference surface is a surface corresponding to a circumference surface of a tissue serving as a reference in determination of a degree of progress of a lesion.

16 . The medical image processing apparatus according to claim 1 ,

wherein the processor is configured to:

determine the measurement reference surface to be used for the measurement according to the lesion region from a plurality of measurement reference surface candidates which are available as the measurement reference surface.

17 . The medical image processing apparatus according to claim 16 ,

wherein the plurality of measurement reference surface candidates include a surface corresponding to an outer circumference of an anatomical tissue.

18 . The medical image processing apparatus according to claim 1 ,

wherein the lesion region is a region of a cancer that develops from epithelial cells, and

the processor is configured to:

select an innermost non-invasion tissue which is a tissue having a region closest to the epithelial cells in a region outside a deepest portion of the cancer, and

determine the measurement reference surface serving as a reference for measurement of the closest distance based on the selected innermost non-invasion tissue.

19 . The medical image processing apparatus according to claim 18 ,

wherein the processor is configured to:

select an outermost invasion tissue which is a tissue farthest from the epithelial cells among tissues which are invaded by the cancer in a region inside the deepest portion of the cancer, and

determine the measurement reference surface serving as a reference for measurement of the farthest distance based on the selected outermost invasion tissue.

20 . The medical image processing apparatus according to claim 1 ,

wherein the processor is configured to:

receive an input of information indicating the measurement reference surface which is designated by using an input device.

21 . The medical image processing apparatus according to claim 1 ,

wherein the processor is configured to:

display a numerical value of the measurement result of the closest distance or a numerical value of the another measurement result of the farthest distance.

22 . The medical image processing apparatus according to claim 1 ,

wherein the processor is configured to:

display a cross-section image of a plane including two points at which at least one distance of the closest distance or the farthest distance is measured.

23 . The medical image processing apparatus according to claim 22 ,

wherein the processor is configured to:

generate a cross-section image of a plane including two points at which the closest distance is measured, and

display the cross-section image.

24 . The medical image processing apparatus according to claim 1 ,

wherein the lesion region is a region of a cancer that develops in a hollow organ, and

the processor is configured to:

present, as a recommended cross-section, a plane which passes through two points at which the closest distance is measured and on which a cross-section area of a hollow organ is smallest or a plane which passes through two points at which the closest distance is measured and of which an angle with a centerline of the hollow organ is closest to 90 degrees.

25 . The medical image processing apparatus according to claim 24 ,

wherein the processor is configured to: after presenting the recommended cross-section,

receive an input of an instruction from a user to designate a plane passing through the two points by using an input device by fixing an axis passing through the two points at which the closest distance is measured, and

generate a cross-section image of the designated plane.

26 . A medical image processing method comprising:

causing a computer to execute:

acquiring a three-dimensional medical image;

receiving an input of information indicating a lesion region included in the medical image;

determining, from the medical image, a measurement reference surface serving as a measurement reference for lesion evaluation;

three-dimensionally measuring a distance between the lesion region and the measurement reference surface;

in response to a first measurement reference surface outside a lesion region being determined as the measurement reference surface, displaying a measurement result including information indicating a closest distance between the lesion region and the measurement reference surface together with the medical image; and

in response to a second measurement reference surface intersecting with the lesion region being determined as the measurement reference surface, displaying another measurement result including information indicating a farthest distance between the lesion region and the measurement reference surface.

27 . A non-transitory, tangible computer-readable recording medium on which a program for causing, when read by a computer, the computer to execute the medical image processing method according to claim 26 is recorded.