JPS5819236A - X-ray photographing apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Description of the field to which the invention pertains) The present invention provides a method for storing a time-series analog/4G video signal obtained as an X-ray image of a photographic object after O/D conversion and storing it in a frame memory. By extracting the concentration cost of the contrast agent at an arbitrary position.

An X-ray imaging device #Ic1I is equipped with a function to calculate the flow velocity and flow rate of blood mixed with a contrast agent.

(Description of Prior Art) When a contrast agent is injected into a subject in a conventional XII imaging apparatus, the contrast agent is used only for the purpose of increasing the contrast of an X-ray image.

Information such as blood volume provided when a contrast agent was injected into the subject was overlooked.

(Objective of the present invention) The present invention provides an X-ray imaging device that can measure temporal changes in contrast agent concentration within a subject into which a contrast agent has been injected, and obtain information such as cliff speed and blood flow rate that are effective for diagnosis. For the purpose of providing.

(Principle of the present invention) Consider imaging a blood vessel mixed with a contrast medium. Since the contrast agent O#i degree changes over time, we set it as -(1) and the output after X-ray detection I(tm+゛' t
g.

I(←/l, 7. 8(1, go),.-1(Riku frame-(1-礪(t)) °y(4a yta-
a t e+”mm (1) Here, 8 (1, go ) is a term that includes all the tube spectrum, object, detector number yield characteristics, etc. J) x ('L
y (to) is the sum of the absorption coefficients of the contrast medium and blood, respectively, and the intravascular thickness, which is the 5ailt17 frame time.

Now, in the angiography shown in Figure 1, there are two points.

BK focuses on 0-02 people, 8 companies, and determines the velocity and volume of blood flow on the blood vessel of the subject to be determined. At this time, the output at point A is expressed as (l(IΔt)−I(represented by equation 1)
・－・・・－・(2
) at the OB point.

-g(t)! (+(1-g(su・y')"i aje
, a.

......-(31 becomes.

Here, a is the time required for the scanning line of the image pickup tube to reach from point A to point B, and Δt is the time required for the blood to reach from point A to point B, that is, the blood flow velocity. -(嘗)
Then, the distance between points A and B is g'7 minus 1 scratch...-Δt(S=5(t)・8
・------= (4).

In (3), t −a '−Δt(st and −
t)・X(E)−(1−iri)・ShikiB−d t ・−···−(5)

Therefore, Δ1 (1 division).

I B (t-a'-xt(t))WI A(t)
−−= (6) and the determined value is 0
That is, I.

(t)I IB(t) Company, the number of people photographed can be obtained as a number value, I(t)e I(t
−)−a), I(t+2m)*−”I(t+”a)(
n: Fray 4) is obtained. For example ■Δt), IB(t)
Figure 2 shows the temporal changes in .

Also, using the mu BMO average cross section width 8, v(t)
...The blood flow rate can be determined by crystal '-'-'<7).

(Description of First Embodiment) An embodiment of the X-ray imaging apparatus according to the present invention for determining blood velocity and volume using the above principle will be described with reference to FIG.

In Fig. 3, fF is emitted from the X-ray tube 1, and II corresponding to the X-ray transmitted image of the subject = an analog video signal obtained from the image pickup tube 2 is passed through the A/D converter 3 to a digital video signal. Convert it.

7 frame memory 4. In this case, the above-mentioned operation is repeated over a predetermined cycle of the TV screen field to obtain n consecutive frames of stored images. After the photographing is completed, the operator selects an appropriate image from the frame memory 4 and displays it on the monitor 5.

Here, the doctor who is the operator selects a blood vessel on the monitor 5 as shown in FIG. 1 and designates two points A and B using a cursor or a light pen. By selecting point A, you can select any J! on the screen. The fourth step is to determine the i mark (i, +i).
Taking into account that the flow velocity is greatly different between the vicinity of the blood vessel wall 8 and the center of the blood vessel, as shown in the figure λ'man, the first calculation !&11t- is carried out to move the designated demon to the center of the blood vessel.

As shown in FIG. 5, when the coordinates <+, j> on the monitor 5 corresponding to the designated demon are given, many straight line groups t1. t2 is considered, and if the distribution of the X-ray images on these straight lines is extracted from memory, both give an appropriate storage hold level of 8, and two points AI that cross that level are
, A2 is the minimum distance, this is regarded as a straight line perpendicular to the direction of the blood vessel. The coordinates of the midpoint bag are obtained from the coordinates corresponding to these two points M* and Ax, and these are again set as the coordinates 11 (i*j) corresponding to the specified point size.

The same is true for B. This allows us to obtain the constant two-point distortion C of the blood vessel site of interest. The flowchart of the first calculation process is shown in FIG. 6. Extract e ■R(su*IQ(')
The function approximation is expressed as follows. IA (Su, Ifi)
Since the shape of t) has a single peak characteristic, Δt(sF
i.

By shifting Ω(1) with respect to t, we can find 1(t) that satisfies the following conditions. Therefore, (3)1 (5), (Using a' used in equation 61, Δ1(Le−1(t ) - a.
A flowchart of the calculation process is shown in FIG.

Next, a third arithmetic process is carried out to obtain the line length S between the measurement points λ9. As shown in FIG. 8, consider a straight line m1 that passes through the center and is perpendicular to the line segment tAK that connects the AI and Am coordinates.

On this direct Ismi, the first arithmetic processing is performed on a predetermined distance marker in the direction from the neck to the platform to obtain Xl.

Let the straight line distance from λ to the 9th plate be ΔS1.

Below, point X which is ΔX advanced from intersection 1! Total 2゜A @ a
: tt, t-'fr calculation shiXki (1kl,,s
, i(,2+-,-...--)m) can be the line length S that is determined to be the closest match to BK. A flowchart of this third calculation process is shown in FIG.

Therefore, we obtain nine constant object points, between θ! 1 degree change time Δ
1 (1), and the line length between t and 0 to calculate the true current velocity -
(st-(41 formula % formula % (4))

In addition, the cross-sectional areas are similarly obtained for A I and A 2 on IA passing through the measurement target point A, and these average values are calculated by
The average blood flow V(r) can also be obtained by multiplying by

The above calculations are performed in the calculation processing section 6 of FIG. 3, and the calculated blood flow velocity -(su) and true flow rate V(ri) are displayed on the display device 7 or the monitor 5.

(Description of the second embodiment) Regarding the first embodiment of the crane, 1. The analog video signal from the camera tube is output directly to the A/D converter 3, and after being converted into a digital video signal, it is stored in the frame memory 4, as shown in this embodiment as shown in FIG. So 1. I--Waikan 2
The continuous analog video signal from the VTJ (video tape recorder) is the video storage means.

After storing it in a VDR (video disc recorder), only the field or fI:, y frame of Wr is extracted as appropriate and outputted to the A/D converter 3, thereby converting it into a digital video signal and storing the frame in memory 4. It is something to remember.

(Effects of the present invention) As described above, the X@ imaging device of the present invention is.

Copy X#11 is converted into four consecutive television fields consisting of an analog video signal sequence by a television 17 means, and the obtained analog video signal is converted into a digital video signal by an A/D converter and then stored in a digital memory. IJK memorize, extract the memory contents corresponding to an arbitrary position in the X fusion that is the 1llJ constant object, and ? 1. This is an X11M imaging device that is capable of calculating and displaying the flow velocity and flow rate of the target area by performing predetermined arithmetic processing in the arithmetic processing unit based on the extracted value.

Blood flow velocity that is clinically useful according to this invention.

Information that was overlooked in conventional X@transmission images, such as blood flow volume, can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining a method for determining measurement points on a blood vessel in an X-ray fluoroscopic image, and FIG. FIG. 3 is a block diagram of an embodiment of the X-ray imaging apparatus according to the present invention. Figures 4 to 6 are diagrams for explaining the first arithmetic processing of the present invention, and Figure 7 is a diagram for explaining the second arithmetic processing theory of the present invention. 8 to 9 are diagrams for explaining the third arithmetic processing of the present invention, and FIG. 10 is a block diagram of a second embodiment of the X@ imaging device according to the present invention. 1...X-ray source 6'... Arithmetic processing unit 2-----Image inteter multi-ear and image pickup tube 3...-A/D converter 7 ;----
-Display device 4... Frame memory, 9...-
1ii Image recording device 5...TV monitor 10.
... Kensuke Nori Chika, patent attorney representing reproduction equipment (
(and 1 other person) Figure 1, Figure 3, Figure 4, Figure 5. 71. l! I Figure 8 Figure 9 [

Claims (1)

[Claims] (1) means comprising an X-ray source for generating an anatomical X-ray image of a subject injected with a contrast agent; television viewing means for converting the x-ray radiation into a continuous television scene field consisting of a sequence of analog video signals;
a MU/D converter for converting the analog video signal into a digital video signal; a digital memory for storing the digital video signal over a predetermined period for a number of consecutive television signal fields;
Extracted from II image. a first calculation means for calculating and outputting a change time in a predetermined range of digital video signals of at least two points at different positions and a distance between the two points; An X@ imaging device comprising: g2 calculating means for calculating and outputting a rate of change between two points; and means for displaying the rate of change from the second calculating means. , in the X@ photographing device according to the first aspect of the present invention, the tenth calculation means calculates and outputs a virtual cross-sectional area from a predetermined distance range in a direction perpendicular to a virtual line connecting at least two extraction points. and an integrating means that integrates the output from the third calculating means and the output from the second calculating means and outputs an integrated value representing the flow rate per unit time. An X-ray imaging device characterized by: