Method and apparatus for measuring a biological function of a subject
First Claim
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1. An apparatus for examining a subject by applying radiation to said subject in synchronism with a cardiac beat phase thereof, comprising:
- means for generating radiation;
means for controlling the radiation generating means so as to project the radiation toward the subject at a predetermined time period;
means for detecting the radiation which has been transmitted through the subject and for producing successively radiation transmission images thereof as digital image signals;
means for temporarily storing a plurality of digital image signals that have been acquired at least during one cardiac beat period respectively before and after a radiation contrast medium arrives in a region of interest within the subject;
means for detecting the cardiac beat period of the subject;
means for quantitatively measuring the biological function of the subject based on the digital image signals acquired at least during one cardiac beat period before and after the penetration of radiation contrast medium into the subject including a time-filtering processor for repeatedly multiplying said digital image signals by respective weighting coefficients and adding said subsequent multiplied signals successively over the one whole cardiac period in synchronism with a given cardiac beat phase to produce time-filtered image signals; and
means for displaying the biological function of the subject based on said time-filtered image signals.
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Abstract
A method and apparatus for examining a subject by applying radiation to the subject in synchronism with a cardiac beat phase of the subject, wherein a digital subtraction is carried out between a mask image and a contrast image derived from the detected radiation which passed through the subject. Cardiac beat phase is detected by measuring the time-elapse characteristic data of image concentration. Based on the measuring time-elapse characteristic data, amplitude and phase images of the cardiac are calculated and displayed.
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Citations
17 Claims
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1. An apparatus for examining a subject by applying radiation to said subject in synchronism with a cardiac beat phase thereof, comprising:
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means for generating radiation; means for controlling the radiation generating means so as to project the radiation toward the subject at a predetermined time period; means for detecting the radiation which has been transmitted through the subject and for producing successively radiation transmission images thereof as digital image signals; means for temporarily storing a plurality of digital image signals that have been acquired at least during one cardiac beat period respectively before and after a radiation contrast medium arrives in a region of interest within the subject; means for detecting the cardiac beat period of the subject; means for quantitatively measuring the biological function of the subject based on the digital image signals acquired at least during one cardiac beat period before and after the penetration of radiation contrast medium into the subject including a time-filtering processor for repeatedly multiplying said digital image signals by respective weighting coefficients and adding said subsequent multiplied signals successively over the one whole cardiac period in synchronism with a given cardiac beat phase to produce time-filtered image signals; and means for displaying the biological function of the subject based on said time-filtered image signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An apparatus for examining a subject by applying radiation to said subject in synchronism with a cardiac beat phase thereof, comprising:
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means for generating radiation; means for controlling the radiation means so as to project the radiation toward the subject at a predetermined time period; means for detecting the radiation which has been transmitted through the subject and for producing successively radiation transmission images thereof as digital image signals; means for temporarily storing a plurality of digital image signals that have been acquired at least during two cardiac beat periods of the subject; means for detecting the cardiac beat period of the subject; means for measuring a biological function based on the digital image signals acquired at least during two cardiac beat periods, including a time-filtering processor for repeatedly multiplying said digital image signals by respective weighting coefficients and adding said subsequent multiplied signals successively over the one whole cardiac period in synchronism with a given cardiac beat in each of the two different cardiac beat periods so as to obtain time-filtered digital image signals; and means for diplaying the biological function based on the time-filtered digital image signals. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17. A method for measuring biological function of a region of a subject, comprising:
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obtaining a plurality of mask image signals in a complete cardiac period before an X-ray contrast medium arrives in the region of the object; obtaining a plurality of contrast image signals in another complete cardiac period after the X-ray contrast medium arrives in said region; producing background removed image signals substantially affected by the contrast medium by subtracting the mask image signals from the contrast image signals in synchronization with the cardiac phase; approximating a time-change of the background removed image signals into at least a first Fourier component image signal of a Fourier series representation thereof, wherein the Fourier series of background removed image signals PC((x, y, t) is defined as follows;
space="preserve" listing-type="equation">PC(x, y, t)=Ao/2+a1 cos (2π
t/Kt)+b1 sin (2π
t/Kt)Tand the first Fourier component is given by;
space="preserve" listing-type="equation">a1 cos (2π
t/Kt)+b1 sin (2π
t/Kt),where a1 and b1 are coefficients and K is the number of data frames in the cardiac periods, comprising producing said a1 and b1 coefficients by repeatedly multiplying the background removed image signals by respective weighting coefficients and adding the subsequently multiplied signals over the whole cardiac period in synchronism with a given cardiac beat phase; and calculating at least one image of amplitude and phase of the first Fourier component image signal.
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Specification