Medical image processing device and X-ray CT device provided with same, and medical image processing method
Even a windmill artifact including a high-frequency component in a plane perpendicular to a rotation axis can be reduced and a boundary of an organ can be made to be clear to maintain the contrast. The invention relates to a medical image processing device and includes an image acquiring unit that acquires a 3D volumetric image, a Z high-frequency image generating unit that generates a Z high-frequency image which is a high-frequency component in a rotation axis direction from the 3D volumetric image, an organ component extracting unit that extracts an organ component from the Z high-frequency image, an artifact component extracting unit that extracts an artifact component on the basis of the Z high-frequency image and the organ component, and a corrected image generating unit that generates a corrected image by subtracting the artifact component from the 3D volumetric image.
1. A medical image processing device comprising:
an image acquirer that acquires a 3D volumetric image;
a Z high-frequency image generator that generates a Z high-frequency image which is a high-frequency component in a rotation axis direction from the 3D volumetric image;
an organ component extractor that extracts an organ component from the Z high-frequency image;
an artifact component extractor that extracts an artifact component on the basis of the Z high-frequency image and the organ component; and
a corrected image generator that generates a corrected image by subtracting the artifact component from the 3D volumetric image.
2. The medical image processing device according to claim 1 , wherein the organ component extractor extracts the organ component by performing a smoothing process on the Z high-frequency image in the rotation axis direction.
3. The medical image processing device according to claim 2 , wherein the Z high-frequency image generator generates a Z image which is an image in the rotation axis direction from the 3D volumetric image and generates the Z high-frequency image by subtracting a Z smoothed image which is an image obtained by performing a smoothing process on the Z image in the rotation axis direction from the Z image, and
wherein smoothing strength for generating the Z smoothed image is less than smoothing strength in the organ component extractor.
4. The medical image processing device according to claim 3 , wherein the smoothing strength in the organ component extractor changes depending on scan conditions or reconstruction conditions which are used to generate the 3D volumetric image.
5. The medical image processing device according to claim 4 , wherein the smoothing strength in the organ component extractor changes to become less as a helical pitch in the scan conditions becomes less.
6. The medical image processing device according to claim 4 , wherein the smoothing strength in the organ component extractor changes to become less as a reconstruction slice thickness in the reconstruction conditions becomes larger.
7. The medical image processing device according to claim 2 , wherein the Z high-frequency image generator generates a first planar image which is an image in a first plane which is a plane along to the rotation axis direction from the 3D volumetric image and generates a first planar high-frequency image by subtracting a first planar smoothed image which is an image obtained by performing a smoothing process on the first planar image in the rotation axis direction from the first planar image,
wherein the Z high-frequency image generator generates a second planar image which is an image in a second plane which is a plane along to the rotation axis direction and perpendicular to the first plane from the first planar high-frequency image and generates the Z high-frequency image by subtracting a second planar smoothed image which is an image obtained by performing a smoothing process on the second planar image in the rotation axis direction from the second planar image, and
wherein smoothing strength for generating the first planar smoothed image and the second planar smoothed image is less than smoothing strength in the organ component extractor.
8. The medical image processing device according to claim 1 , wherein the artifact component extractor extracts the artifact component by subtracting the organ component from the Z high-frequency image.
9. The medical image processing device according to claim 1 , wherein the organ component extractor converts a pixel value of a pixel of which the pixel value is higher than a threshold value in the Z high-frequency image into a pixel value equal to or less than the threshold value to generate a converted Z high-frequency image and extracts the organ component by performing a smoothing process on the converted Z high-frequency image in the rotation axis direction.
10. The medical image processing device according to claim 1 , wherein the artifact component extractor extracts the artifact component by adding a result obtained by performing a smoothing process on the organ component along a plane perpendicular to the rotation axis to a result obtained by subtracting the organ component from the Z high-frequency image.
11. The medical image processing device according to claim 1 , wherein the image acquirer is configured to acquire the 3D volumetric image again.
12. An X-ray CT device comprising the medical image processing device according to claim 1 .
13. A medical image processing method comprising:
an image acquiring step of acquiring a 3D volumetric image;
a Z high-frequency image generating step of generating a Z high-frequency image which is a high-frequency component in a rotation axis direction from the 3D volumetric image;
an organ component extracting step of extracting an organ component from the Z high-frequency image;
an artifact component extracting step of extracting an artifact component on the basis of the Z high-frequency image and the organ component; and
a corrected image generating step of generating a corrected image by subtracting the artifact component from the 3D volumetric image.