Method and apparatus for measuring a biological function of a subject

DETAILED DESCRIPTION Accordingly, an object of the present invention is to provide a novel radiation diagnostic method and apparatus for producing sharpened images without artifact due to differences in the cardiac beat phases.
Another object of this invention is to provide a novel radiation diagnostic method and apparatus which can quantitatively produce a diagnostic image including biological function information.
These and other objects are achieved according to the invention by providing a novel method for measuring a biological function of a subject and a novel apparatus for implementing the method, including means for obtaining a plurality of mask images in a complete cardiac period before an X-ray contrast medium arrives at a region of interest in the subject, means for obtaining a plurality of contrast images in another complete cardiac period after the X-ray contrast medium arrives at the region of interest; means for producing background removed imaged substantially affected by the contrast medium by subtracting the mask images from the contrast images in synchronism with cardiac phase; means for approximating a time-change of the background removed images into at least a first Fourier component image of the Fourier series thereof; and means for calculating at least one image of amplitude and phase of the first Fourier component image.
The method and apparatus according to the present invention can produce the amplitude image and the phase image of the cardiac beat movement from the X-ray penetration images during at least one cardiac beat period before and after the injection of the contrast medium, and these images can be displayed on the monitor quickly, whereby biological function of the heart can be measured and diagnosed quantitatively.
Furthermore, the acquired images are subtracted by a time-filtering process based upon the cardiac beat period.
Therefore the present invention can produce the amplitude image and the phase image of the heart with high precision and without the artifact due to cardiac pulsatory movement