X-RAY DIAGNOSTIC APPARATUS, IMAGE PROCESSING APPARATUS, AND PROGRAM

Abstract

An X-ray diagnostic apparatus includes an image generating unit which generates a plurality of X-ray images by repeatedly radiographing a subject before and after injection of a contrast medium, a region detecting unit which detects a non-contrast region from a plurality of mask images before injection of the contrast medium and a plurality of contrast images after injection of the contrast medium, which constitute the plurality of X-ray images, a mask selecting unit which separately selects one mask image with respect to each of the contrast images on the basis of a correlation between the contrast image and the mask image upon localization to the non-contrast region, and a subtraction processing unit which generates a subtraction image by performing subtraction between the contrast image and the selected mask image.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the invention.

FIG. 1 is a block diagram showing the arrangement of an X-ray diagnostic apparatus according to an embodiment of the present invention;

FIG. 2 is a view showing an example of an initial window in this embodiment;

FIG. 3 is a flowchart showing a semi-automatic processing procedure in this embodiment;

FIGS. 4A to 4F are supplementary views for second ROI detection processing in FIG. 3;

FIG. 5 is a supplementary view for bottom trace image generation in FIG. 4;

FIG. 6 is a flowchart showing an automatic processing procedure in this embodiment;

FIG. 7 is a view showing an electrocardiographic waveform for supplementarily explaining automatic sorting of mask images and contrast images in a modification to this embodiment;

FIG. 8 is a graph showing temporal changes in the total sum value of subtraction images;

FIG. 9A is a view showing original mask images handled in optimal mask selection step S03 in FIG. 3;

FIG. 9B is a view showing original contrast images handled in optimal mask selection step S03 in FIG. 3;

FIG. 10A is a view showing mask images from which blood vessel regions are removed in step S03 in FIG. 3;

FIG. 10B is a view showing contrast images from which blood vessel regions are removed in step S03 in FIG. 3; and

FIG. 11 is a view showing that a mask image M3 is selected with respect to a contrast image M2 in step S03 in FIG. 3.

Claims

1. An X-ray diagnostic apparatus comprising: an image generating unit which generates a plurality of X-ray images by repeatedly radiographing a subject before and after injection of a contrast medium;a region detecting unit which detects a non-contrast region from a plurality of mask images before injection of the contrast medium and a plurality of contrast images after injection of the contrast medium, which constitute said plurality of X-ray images;a mask selecting unit which separately selects one mask image from said plurality of mask images with respect to each of the contrast images on the basis of a correlation between the contrast image and the mask image upon localization to the non-contrast region; anda subtraction image generating unit which generates a subtraction image by performing subtraction between the contrast image and the selected mask image.

2. An apparatus according to claim 1, further comprising an operating unit which designates an acquisition time for the mask images; anda control unit which controls outputting of a contrast medium injection instruction at a point of time at which the set acquisition time has elapsed from the start of radiography.

3. An apparatus according to claim 1, further comprising an operating unit which operates to sort said plurality of X-ray images into the mask images and the contrast images.

4. An apparatus according to claim 1, further comprising an image sorting unit which sets, as tentative mask images, X-ray images of said plurality of X-ray images which correspond to at least one cycle of an electrocardiogram and are obviously recognized as being less influenced by the contrast medium, generates a plurality of subtraction images with different electrocardiographic phases by performing subtraction between the tentative contrast images and tentative mask images whose electrocadiographic phases are nearest to those of the tentative contrast images, and sorts said plurality of X-ray images into the mask images and the contrast images on the basis of changes in pixel values of said plurality of subtraction images.

5. An apparatus according to claim 4, wherein the image sorting unit separates the contrast images into a plurality of first contrast images and a plurality of second contrast images,the mask selecting unit selects one mask image with respect to each of the first contrast images on the basis of correlations between the first contrast images and the mask images, andthe subtraction image generating unit generates a subtraction image by performing subtraction between the first contrast image and the selected mask image.

6. An apparatus according to claim 5, wherein the image sorting unit separates the first contrast image and the second contrast image before and after the start of movement of a bed top on which the subject is placed.

7. An apparatus according to claim 5, wherein the image sorting unit separates the first contrast image and the second contrast image before and after the start of movement of at least one of a collimator and a compensation filter.

8. An apparatus according to claim 1, wherein the region detecting unit generates a first minimum value projection image from said plurality of mask images by projection processing in a time-axis direction, generates a second minimum value projection image from said plurality of contrast images, and detects the non-contrast region on the basis of a subtraction image between the first minimum value projection image and the second minimum value projection image.

9. An apparatus according to claim 1, wherein the region detecting unit detects a body movement region which is the non-contrast region and in which relatively large body movement of the subject has occurred from the mask image and the contrast image, andthe mask selecting unit obtains a correlation between the contrast image and the mask image with respect to the body movement region.

10. An image processing apparatus comprising: a region detecting unit which detects a non-contrast region from a plurality of mask images before injection of a contrast medium and a plurality of contrast images after injection of the contrast medium which constitute a plurality of X-ray images generated by repeatedly radiographing a subject before and after injection of the contrast medium;a mask selecting unit which selects one mask image with respect to each of the contrast images on the basis of correlations between the contrast images and the mask images which are associated with the non-contrast region; anda subtraction image generating unit which generates a subtraction image by performing subtraction between the contrast image and the selected mask image.

11. A program for causing a computer to implement: means for detecting a non-contrast region from a plurality of mask images before injection of a contrast medium and a plurality of contrast images after injection of the contrast medium which constitute a plurality of X-ray images generated by repeatedly radiographing a subject before and after injection of the contrast medium;means for selecting one mask image with respect to each of the contrast images on the basis of correlations between the contrast images and the mask images which are associated with the non-contrast region; andmeans for generating a subtraction image by performing subtraction between the contrast image and the selected mask image.