CN1124613A - Digital shadow-reduced angiographic system for stereoscopic X-ray apparatus - Google Patents

Abstract

The stereo angiography system for X-ray machine features use of microcomputer, special image processing and operational system, real-time mass frame-memory capacity, and flexible control unit using large-scale IC to form dual-channel stereo DSA system, as well as man-machine interaction mode to correctly calculate the information on focus depth and analyze 3-D form of blood vessel. Modular structure and real-time video bus are designed for image processing and data storing.

Description

Digital shadow-reduced angiographic system for stereoscopic X-ray apparatus

The invention belongs to technical field of medical instruments, further belong to the digital subtraction angiography system (claiming DSA-DigitalSubtraction Angiography again) that is used to radiate diagnostic imaging and treatment.

Along with development of modern science and technology, technological means that some are advanced and computer science and technology constantly are being applied to medical domain, and particularly in radiodiagnosis and treatment subject, computer image processing is being brought into play more and more important effect.Cardiovascular disease is the very high class disease of human mortality rate, and the morphosis that obtains blood vessel by imaging technique has great clinical value, because it has reflected the essential information of multiple pathological changes.Current, the modern medicine image device can provide the multiple method (resembling as ultrasonic, nuclear magnetic resonance, NMR, X line chart) that can be used for the blood vessel imaging from technical standpoint, but because some specific (special) requirements of angiocardiography technology: need very high imaging speed, to guarantee to obtain athletic heart image and very high pattern space resolution clearly, to debate not fine coronary artery structure, because the motion of heart (about 80 times/minute of average heart beating, the highest instantaneous linear velocity can reach 1 meter per second), have only the imaging of pulse X line can satisfy above-mentioned requirements.Therefore the present X line chart that remains that the most generally is used for clinical medicine of cardioangiography resembles, and promptly utilizes the DSA technology to diagnose the pathological changes situation relevant with blood vessel, and can cure angiopathy or cancer by interventional therapy.

That at present develops and produce DSA equipment in the world has Siemens (Digitron-2), a U.S. GE company (DF-5000), Japan Toshiba (DIGEFORMER-HR), Tianjin, island companies such as (DAR-1200), common defective is in existing DSA product: adopt the single channel structure, to two two-dimensional x-ray images that two bulbs (or single bulb bifocus) of three-dimensional X line machine are produced, can't carry out real-time synchronous acquisition, handle and demonstration.Though some external DSA products are furnished with the stereovision visor as DIGEFORMER-HR system of Toshiba, this class formation remains on single pass basis, utilizes individual monitor, and timesharing shows left and right two dimension view.Adopt the observation visor of liquid crystal photoswitch, make the observation and the left and right view on the display of images of left and right eyes synchronous, make people's observation produce the stereo image effect, this method can't be carried out accurately, and the focus depth information calculates, and the accurate location of focus and depth calculation are very important key technologies for the interventional therapy of cardiovascular disease, in existing DSA clinical instrumentation, it substantially all is to realize by designing special function key, parameter key and supporting hardware circuit that the setting of working method and parameter are selected.Obviously, by the control circuit of this pattern design hardware complexity height not only, cost is big, and owing to its alternative parameter all is fixed and has only limited some, therefore, both limited its range of application, and can have influence on angiography to a certain extent again or subtract the quality of shadow.In addition, present existing DSA equipment all is according to its specific function and specialized designs circuit separately, complex structure, maintenance difficult, cost are very high, and the user can't further carry out applied research work and original system be carried out the expansion of technical specification according to the needs of controlling oneself on these equipment.

The objective of the invention is in order to overcome the defective and the deficiency of existing DSA equipment, a kind of dual pathways Processing Structure that has is provided, and can accurately calculate lesions position or blood vessel three dimensional structure information (being depth information), control flexibly, be convenient to expand, three-dimensional X line machine digital subtraction angiography equipment that cost is low.

Purpose of the present invention can reach by following measure, adopt two computers (PC) to constitute duplex computer spatial parallelism Processing Structure, adopt the identical real-time image processing system of two nested structures, the STD bus slot by PC links to each other with computer respectively.The picture inversion that the industry gamma camera resembles multiplier tube with the X line chart becomes the TV signal of a customized type, under the effect of control unit, send into left and right passage computer image processing system through multi-channel switcher respectively by single, double order (corresponding left and right view), treated picture intelligence is stored in during the magnanimity frame deposits by the real-time video bus, is also shown on the monitor simultaneously.Computer RS232C standard interface in the DSA system is used to finish two control data communications between the passage.Utilize the stereopsis visor that the image of the shown same position of the human body different angles of two monitors is carried out binocular observation, and rolling mouse is determined corresponding corresponding point, according to the two-dimensional coordinate of the corresponding point that computer calculated, the 3 d space coordinate that is calculated this point by the depth calculation program is a depth information again.Control unit in the system can be finished all parameter settings that subtract the shadow working method and the control of X ray tube time of exposure.The hardware of whole system and software design utilize the Standard PC bus to realize modularity, hierarchical structure.

The invention will be further described below in conjunction with accompanying drawing.

Fig. 1 is an overall structure block diagram of the present invention.

Fig. 2 is a control unit block diagram of the present invention.

Fig. 3 is X ray tube time of exposure control principle figure of the present invention.

Fig. 4 is that X ray tube exposed pulse of the present invention and video signal concern sketch map.

Fig. 5 is an X ray tube exposure parameter control unit schematic diagram of the present invention.

Fig. 6 is an of the present invention pair of bulb synchronization control circuit schematic diagram.

Fig. 7 is a control unit working method signal generation main circuit block diagram of the present invention.

Industrial gamma camera 1 of the present invention will be converted to the TV signal of a customized type from the visible image of visual multiplier tube.This signal is sent into left and right passage computer image processing system by multi-channel switcher 2 respectively by single, double order (images of the same position of the human body that corresponding left and right bulb produced different angles) under the control unit effect of system.4 and 11 is visual A/D conversion and operation processing unit, 5 and 12 is the real-time video bus, 6 and 13 is that the real time mass frame is deposited, 7 and 14 is the computer keyboards that have mouse, 8 and 15 is computer bus, 9 and 16 is graphics terminals, and 10 and 17 is RS232C serial communication interfaces, utilizes the keyboard 7 of left passage computer to realize the control of two passage computers by this interface.4, the left passage of the three-dimensional DSA of 5,6,7,8,9,10 compositions system; 11, the right passage of the three-dimensional DSA of 12,1314,15,16,17 compositions system.Image A/D conversion and operation processing unit 4 are removed the A/D conversion of finishing picture intelligence, and the main real-time processing that realizes the X ray image has the I/O look-up table in processing unit 4,16 arithmetic units and 8 * 8 multipliers.Allow on its video bus 5 that the real time mass frame of external expansion deposits 6, be used to store the result of image subtraction behind long X ray image or the injection of contrast medium.Deposit X ray image in 6 or image subtraction result's image is presented on the color display 9 at the magnanimity frame.The control subsystem 3 of DSA system is to connect x-ray system, and image processing system 4 links to each other with other external equipment by left passage computer bus (data/address bus, address bus, control bus) 15.Its effect is that the control instruction in the DSA systems soft ware is converted to various working method signals, controls the time of exposure of X ray tube, coordinates the synchronous working of left and right sides channel images processing system.Various working methods preset and parameter to select all be to realize by the computer program menu.Graphics terminal 9 and 16 demonstrations subtract shadow or visual post processing result from left and right channel images.The three-dimensional quantitatively optics visor 20 of depth measurement is placed on display terminal 9 and 16 dead aheads, the operator is by 20 images that make its left eye viewing terminal 9, the image of right eye viewing terminal 16, rolling mouse 7 then, under the situation of Real Time Observation image, cursor point on left and right two images is overlapped, restart the depth data that the depth measurement subprogram just can calculate this point.

Realize that in conjunction with Fig. 3,4,5,6 pairs of control system X ray tube Exposure mode and various system subtract the shadow working method and be described further.The content that the time of exposure control of X ray tube is comprised two aspects: the Exposure mode of (1) control X ray tube; (2) the exposure starting point and the persistent period of control X ray tube.Wherein, the Exposure mode signal determines which X ray tube exposes, do not expose in which field, and the task of (2) then is in one time range (20ms), at those the definite video fields that will expose, controls its exposure starting point and persistent period.Both combine and can realize the control of the time of exposure of X ray tube.Fig. 3 shows the relation between the two and the exposure time control signal.Wherein, waveform II is the Exposure mode control signal, and waveform I is the pulse signal that a frequency equates with field frequency then, controls phase place and pulsewidth that this signal is in the field blanking tailing edge, can realize X ray tube exposure starting point and the control of persistent period.With signal I and signal II logically with can get signal III, this signal promptly can be used as the exposure time control signal of X ray tube after overdriving.

Describe the control of X ray tube Exposure mode below in detail.

Exposure starting point and these two the parameter controls of length of exposure in a field time of X ray tube are undertaken by circuit shown in Figure 5.Wherein field signal is provided by visual A/D conversion and operation processing unit 4.

The relation of field signal and video signal as shown in Figure 4.After three 8253 programmable counts/intervalometer conversion in this signal process circuit shown in Figure 5, becoming one-period is field duration (20ms), phase place and the adjustable square wave of pulsewidth, signal in the arteries and veins that promptly exposes.Ts among Fig. 4, Tw represent the exposure starting point and the persistent period of X ray tube, and the count value of change 8253 can change exposure starting point and length of exposure.

Under three-dimensional mode, under promptly two bulb working methods, obtain good volume rendering image or solid and subtract the shadow result, control subsystem will guarantee that not only the exposure of image processing system and X ray tube is synchronous, also to satisfy the requirement of left and right two channel images processing system coordinate synchronization, with the exposed pulse signal that X ray tube exposed pulse generation circuit 23 produces, just can realize above-mentioned requirements through the suitable extremely two bulb synchronization control circuits (Fig. 6) of working method signal that the DSA System planes/three-dimensional mode commutation circuit 25 produces.

The present invention adopts dual pathways treatment technology, simultaneously the image of two passages is presented at the display terminal 9,16 of two correspondences respectively, can observe three-dimensional image by control signal wire 19 with true stereo sense, adopt man-machine interaction mode when observer's eyes are observed by 20, move the cursor on two display terminals 9,16, observe 20 simultaneously at observer's eyes, two corresponding point on the image are overlapped, calculate the three-dimensional space coordinate of measured point then with computer program according to the two-dimentional coordinate of two corresponding point.

Geometrical relationship according to image space and object space is utilized following formula

D＝LB/(B＋KI)

Can calculate the three-dimensional coordinate of object space point, K is the conversion coefficient of imaging system in the formula, and B is the distance between left and right canopy control X ray tube focus, L be the bulb focus to the distance of placing object plane, I is that image pixel is counted.

Control unit is one of important subsystem in the three-dimensional X line digital subtraction angiography system, is the key link that connects x-ray system, image processing system, computer and external equipment.Its effect is that the control instruction in the systems soft ware is converted to various working method signals, controls the time of exposure of X ray tube, coordinate the synchronous working of left and right sides channel images processing system and ECG external trigger synchronously.

Control system initialization and visual frame number are provided with 21 initialization and the System self-test of finishing the DSA system, and subtract the visual frame number that shadow needs automatic setting magnanimity frame is deposited the needs storage in 6 according to different, parameter is sent to subtracts shadow mode signal generation main circuit 22 simultaneously.Control logic circuit 26 receive from 22 subtract shadow working method signal, and with from the combination of the exposure time control signal of X ray tube exposed pulse generation circuit 23, and producing the synchronous control signal 19 of left and right X ray tube timing control signal 18 and dual pathways image processing system 2,11 by power drive 29, X ray tube exposed pulse generation circuit 23 also needs to receive the field sync signal from A/D conversion and operation processing unit 4 and 11.Plane/stereo mode commutation circuit 25 can realize the working method switching of this system.Image sequence that is produced when left and right X ray tube and left and right channel program utilize program to adjust circuit 28 by left and right frame synchronization not at once, can change the output channel of multi-channel switcher 2.Subtracting shadow working mode selection circuit 24 produces according to the data on the data/address bus and subtracts shadow working method signal accordingly and be sent to and subtract shadow working method signal generation main circuit 22.Control system start-up control circuit 27 also can be finished the synchronous of ECG external trigger.

Control unit normally steady operation is directly connected to the reliability and the image processing result of whole DSA system.Compare with DSA and traditional equipment, this control unit not only can provide volume rendering and solid to subtract the shadow function, and supports the multiple shadow working method that subtracts.In addition, preset and the parameter of various working methods select all to realize by the computer program menu therefore have very big motility and wider adaptive surface.

The present invention adopts the image processing arithmetic system of microcomputer, special use and the Flexible Control unit that large scale integrated circuit was deposited and used to the real time mass frame, constitute the three-dimensional DSA of dual pathways system, and utilized the man-machine interaction mode depth information and the three-dimensional configuration of analyzing blood vessel of calculating foci exactly.In the design of hardware and software, adopted the module hierarchical structure, designed the real-time video bus simultaneously and realized image processing and data storage.Overall structure is simple, reliable, is convenient to maintenance.

Claims (3)

1, digital shadow-reduced angiographic system for stereoscopic X-ray apparatus, it comprises the system that carries out image processing with computer, gamma camera and visual real-time processor, it is characterized in that: described computer-controlled image processing system adopts two PCs to constitute duplex computer spatial parallelism Processing Structure, identical real-time image processing system of two nested structures and magnanimity frame are deposited, STD bus slot by PC links to each other with computer respectively, has adopted modularity, hierarchical structure.

2, digital shadow-reduced angiographic system for stereoscopic X-ray apparatus as claimed in claim 1, it is characterized in that: described gamma camera becomes the picture inversion of visual multiplier tube the TV signal of one customized type, under the effect of control unit, press single through multi-channel switcher, two order are sent into a left side respectively, right passage computer image processing system, treated picture intelligence is stored in during the magnanimity frame deposits by video bus, send monitor to show simultaneously, computer RS232C standard interface is adopted in control data communication between two passages, realize the operation of two computers by a keyboard, the stereopsis visor is used for the image of the shown human body different angles of two monitors is carried out binocular observation, determine a left side by mouse, corresponding corresponding point on the right two-dimensional image, according to the two-dimensional coordinate of the corresponding point that provided, the 3 d space coordinate that is calculated this point by computer program automatically is a depth information again.

3, digital shadow-reduced angiographic system for stereoscopic X-ray apparatus as claimed in claim 1, it is characterized in that: control system initialization and visual frame number set up into the initialization and the System self-test of DSA system, and according to different subtract shadow needs automatic setting magnanimity frame deposit in the visual frame number of required storage, simultaneously parameter is sent to and subtracts shadow mode signal generating circuit, control logic circuit is accepted from the signal that subtracts shadow mode signal generating circuit, with produce a left side from the combination of the exposure time control signal of X ray tube exposed pulse generation circuit and by power drive, the synchronous control signal of right X ray tube timing control signal and dual pathways image processing system, X ray tube exposed pulse generation circuit is also accepted the field sync signal from A/D conversion and operation processing unit, commutation circuit is used for the switching of plane/stereo working method, utilize program to pass through a left side, right frame synchronization is adjusted the output channel that circuit changes multi-channel switcher, subtract shadow working mode selection circuit and produce according to the data on the data/address bus and subtract shadow working method signal accordingly and be sent to and subtract shadow working method signal generating circuit, control system start-up control circuit finish the ECG external trigger synchronously.

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