Image processing device and X-ray diagnostic apparatus

1. An image processing device, comprising:

processing circuitry configured to

sequentially acquire image data of a DSA image of time-sequential DSA images of an object,

sequentially acquire, each time image data of a DSA image of a latest time phase is acquired, a parameter value for each pixel based on a temporal change of a pixel value of each pixel corresponding to a same region of the object in the sequentially acquired image data of the DSA image of the time-sequential DSA images of the object, the parameter value at each pixel being a value that represents a time at which a parameter satisfies a predetermined condition defined for the parameter and the parameter value at each pixel being a value that is fixed for each of the sequentially acquired image data as it is sequentially acquired and does not change thereafter, and

sequentially generate, each time the image data of the DSA image of the latest time phase is acquired, image data of a parameter image in such a manner that identification information according to the parameter value of each pixel is assigned to each pixel corresponding to the same region.

2. The image processing device according to claim 1 , wherein the processing circuitry is further configured to

make a display sequentially display the parameter images based on the image data of parameter images.

3. The image processing device according to claim 1 , wherein the processing circuitry is further configured to:

sequentially acquire the image data of the DSA image of the time-sequential DSA images generated in real-time by fluoroscopic imaging on the object,

sequentially generate, each time the image data of the DSA image of the latest time phase is acquired, image data of parameter images such that each of the parameter images reflects image data of the DSA image of a corresponding latest time phase, and

sequentially generate, each time the image data of the DSA image of the latest time phase is acquired, image data of a composite image, wherein the composite image is obtained by composing the DSA image and the parameter image corresponding to the latest time phase.

4. The image processing device according to claim 3 , wherein the processing circuitry is further configured to

sequentially generate the composite image data of the composite image by composing the parameter image corresponding to the latest time phase and the DSA image of the latest time phase.

5. The image processing device according to claim 3 , wherein the processing circuitry is further configured to

sequentially generate composite image data of composite images, each of which is obtained by composing a representative DSA image commonly used for generating the composite images and the parameter image corresponding to the latest time phase.

6. The image processing device according to claim 3 , wherein the processing circuitry is further configured to

sequentially generate composite image data of composite images, each of which is obtained by composing an average image of DSA images of consecutive time phases commonly used for generating the composite images and the parameter image corresponding to the latest time phase.

7. The image processing device according to claim 3 , wherein the processing circuitry is further configured to

generate image data of a unified parameter image in which acquired image data of DSA images of all time phases are reflected, and

generate composite image data of composite images corresponding to respective DSA images, by composing the unified parameter image and each of the DSA images.

8. The image processing device according to claim 3 , wherein the processing circuitry is further configured to

generate image data of a unified parameter image in such a manner that DSA images of consecutive time phases as a part of acquired DSA images of all time phases are reflected, and

generate composite image data of composite images corresponding to respective DSA images, by composing the unified parameter image and each of the DSA images.

9. The image processing device according to claim 1 , wherein the processing circuitry is further configured to

acquire a first time phase, at which a contrast agent concentration exceeds a threshold value, as the parameter value.

10. The image processing device according to claim 1 , wherein the processing circuitry is further configured to

sequentially generate the image data of parameter images, by coloring each pixel corresponding to the same region of the object according to the parameter value.

11. An X-ray diagnostic apparatus, comprising:

an X-ray imaging device configured to generate projection data of time-sequential X-ray images by detecting X-rays passing through an object before and after administration of a contrast agent, and generate image data of time-sequential DSA images of the object based on each subtraction between an X-ray image before the administration of the contrast agent and each of time-sequential X-ray images after the administration of the contrast agent; and

the image processing device according to claim 1 .

12. The image processing device of claim 1 , wherein the processing circuitry is further configured to generate the image data of the parameter image so that, for each pixel in the parameter image, the identification information is determined and fixed based on a corresponding parameter value of the pixel.

13. The image processing device of claim 1 , wherein

the parameter value for each pixel of a third DSA image of the time-sequential DSA images is generated based upon the temporal change over a first time phase through a third time phase corresponding to a first DSA image through the third DSA image of the time-sequential DSA images, respectively, and does not change thereafter, and

the parameter value for each pixel of a fourth DSA image of the time-sequential DSA images is generated based upon the temporal change over the first time phase through a fourth time phase corresponding to the first DSA image through a fourth DSA image of the time-sequential DSA images, respectively, and does not change thereafter.

14. The image processing device of claim 13 , wherein

a third parameter image is generated based upon the parameter value for each pixel of the third DSA image and a unified color table, and

a fourth parameter image is generated based upon the parameter value for each pixel of the fourth DSA image and the unified color table.

15. An image processing method, comprising:

sequentially acquiring image data of a DSA image of time-sequential DSA images of an object,

sequentially acquiring, each time image data of a DSA image of a latest time phase is acquired, a parameter value for each pixel based on a temporal change of a pixel value of each pixel corresponding to a same region of the object in the sequentially acquired image data of the DSA image of the time-sequential DSA images of the object, the parameter value being a value that represents a time at which a parameter satisfies a predetermined condition defined for the parameter and the parameter value at each pixel being a value that is fixed for each of the sequentially acquired image data as it is sequentially acquired and does not change thereafter, and

sequentially generating, each time the image data of the DSA image of the latest time phase is acquired, image data of a parameter image in such a manner that identification information according to the parameter value is assigned to each pixel corresponding to the same region.