Method for discriminating x-ray contrast image from non-contrast image and x-ray imaging system including contrast image discriminating function

摘要

To discriminate a contrast image from a non-contrast image, an X-ray imaging method (100) is characterized by comprising the steps of: acquiring a plurality of X-ray images (Xi) of a biological body (20) under medical examination; subtracting at least two sets of the X-ray images (Xi:Xi-1) with each other acquired at temporally different timings to obtain a subtraction image (Gi); subdividing one subtraction image (Gi) into a plurality of image blocks (B₀₀:B₃₃); calculating an averaged value of image concentration with respect to each of the image blocks (B₀₀:B₃₃), thereby obtaining a plurality of averaged values for the subdivided image blocks (B₀₀:B₃₃); calculating a difference between at least two averaged values of image concentration with respect to the image blocks (B₀₀:B₃₃) acquired within substantially same temporal timing period; and, judging whether or not the X-ray image (Xi) is acquired under such a condition that an X-ray contrast medium appears therein based upon the difference in said two averaged values of image concentration.