CN100462050C - X-ray CT apparatus and myocardial perfusion image generating system - Google Patents
X-ray CT apparatus and myocardial perfusion image generating system Download PDFInfo
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Abstract
An X-ray CT apparatus 1 for radiating X-ray to a subject P so as to scan the subject P and reconstructing a image within the subject P based on an obtained projection data comprises an image generating unit and a blood-flow image generating unit 24e. The image generating unit generates the image based on the projection data in a state in which a concentration of a contrast medium in a myocardial portion of a subject P continuously injected the contrast medium can be considered to be constant. The blood-flow image generating unit 24e generates a blood flow image by removing components of a myocardial tissue from a portion of a myocardial region of the image generated by the image generating unit.
Description
The cross reference of related application
The application about and introduce as a reference Japanese patent application 2004-174364 number of submitting on June 11st, 2004 and submission on January 13rd, 2005 Japanese patent application 2005-005977 number.
Technical field
The present invention relates to a kind of X ray CT (computer topography art) equipment and myocardial perfusion image generating system, it obtains radiography CT image by injecting contrast agent continuously, coronarography CT image for example, cardiomyography CT image etc., and use the radiography CT image that obtains to produce myocardial perfusion imaging.
Background technology
About using the cardiomyography inspection of X ray CT device, contrast agent is injected among the person under inspection as patient, and radiography CT image is collected.Subsequently, the live image of coronary artery, endocardium internal chamber wall etc. produces from the radiography CT image of collecting, and is used for diagnosis.
Equally, Xin Ji blood flow dynamically (perfusion) check and used the X ray CT device realization about the perfusion inspection of organ in the cerebral tissue for example.Check that about these perfusions the dynamic arthrography CT data of attempting to be obtained from dynamic imaging by the bolus injection that injects contrast agent by analysis in a short time produce perfusion image and are studied routinely.
But usually, this Perfusion Imaging is not independently to check, but carries out as the part of contrast examination.For example, if myocardial perfusion imaging takes place, be used for cardiac function and for example analyze that the scanning of coronary artery and the motion of endocardium inner chamber also is performed, as the scanning of myocardial perfusion imaging.Therefore, the scanning of myocardial perfusion imaging cost is long-time, and the inspection method that causes the x-ray dose of person under inspection's ray to increase is almost unacceptable, therefore, uses the long-term dynamics imaging of X ray CT device also not obtain actual use up to now.Consider the perfusion inspection of this background use about the cerebral tissue inner capillary tube, contrast agent once is injected into the person under inspection, and image obtains in a short time, and (the Japanese uncensored patent application of reference is delivered 2003-116843 number, for example).More particularly, contrast agent uses a kind of technology to inject, and makes to form in the concentration change of the contrast agent of time peak value in being embedded into the person under inspection, and uses the imaging of X ray CT device and the time synchronized execution that contrast agent moves to the cerebral tissue inner capillary tube.Subsequently, about of the CT image acquisition that time-concentration change, use by use X ray CT device imaging obtain of dabbling information based on contrast agent in the cerebral tissue inner capillary tube.
But, about obtaining routine techniques about dabbling information by contrast agent once being injected into the person under inspection, person under inspection's x-ray bombardment may be limited as the imaging time amount period, but other x-ray imaging for collect remove pour into the data of organ for example coronary artery image and cardiac function analytical data are essential.Therefore, need the photography further minimizing in period.
In addition, number of times that contrast agent injects and injection rate increase and increase along with imaging time, carry out because scanning is respectively myocardial perfusion imaging and obtaining of myocardium image.But, have the upper limit about the injection rate of person under inspection's contrast agent, thereby the time quantum of imaging and number of times thereof are also limited.Therefore, this proposition is difficult to guarantee the problem that grows up to the picture time of myocardial perfusion imaging.
Summary of the invention
Therefore, the present invention considers regular situation and creates, and the object of the present invention is to provide a kind of X ray CT device and myocardial perfusion image generating system, it is used for producing in a short time myocardial perfusion imaging, reduces simultaneously about the injection rate of person under inspection's contrast agent with owing to the dosage of X ray.
On the one hand, in order to realize this purpose, the invention provides a kind of radiate X ray to the person under inspection so that scanning person under inspection and rebuild the X ray CT device of image in the person under inspection based on the data for projection that obtains, comprise: the concentration at the person under inspection's cardiac muscle part contrast agent that injects contrast agent continuously is considered under the constant state, produces the image generation unit of image based on data for projection; And the blood-flow image generating unit of assigning to produce blood-stream image by the one-tenth of from the myocardial region part of the image that produces by image generation unit, removing cardiac muscular tissue.
In addition, X ray CT device comprises definite territory element of the myocardial region part of determining the image that produced by image generation unit, and wherein blood-flow image generating unit is configured so that from by the composition of determining to remove the myocardial region part that territory element is determined cardiac muscular tissue.
In addition, image generation unit is configured so that produce blood-stream image by deduct the CT value that is equivalent to cardiac muscle from myocardial region partial C T image.
In addition, X ray CT device comprise when carry out that gradation conversion is at least handled and during the tone conversion process, based on by the corresponding value of myocardium part of contrast agent radiography with the corresponding value of cardiac muscle own the display processing unit of the value of window position is set.
In addition, X ray CT device comprises when carrying out at least that gradation conversion is handled and the value of window position is set during the tone conversion process, so as to emphasize to have with by the corresponding value of myocardium part of contrast agent radiography and and myocardium corresponding value own between the display processing unit of pixel of value.
In addition, on the one hand, in order to realize this purpose, the invention provides a kind of X ray CT device, comprising: the concentration that contrast agent is injected into the person under inspection continuously and obtains contrast agent in person under inspection's cardiac muscle part is considered to the contrast medium injector of constant state; The concentration of contrast agent is considered to synchronously collect the image collection unit of radiography CT image with electrocardiogram during constant in cardiac muscle part; And the blood-flow image generating unit that produces blood-stream image by the CT value that from the radiography CT view data of cardiac muscle part, deducts cardiac muscle.
In addition, on the one hand, in order to realize this purpose, the invention provides a kind of myocardial perfusion image generating system, comprising: the image acquisition unit that is considered to obtain under the constant state image in the person under inspection's who injects contrast agent continuously the myocardium partly concentration of contrast agent; And the blood-flow image generating unit of assigning to produce blood-stream image by the one-tenth of from the myocardial region part of the image that obtains by image acquisition unit, removing cardiac muscular tissue.
In addition, on the one hand, in order to realize this purpose, the invention provides a kind of myocardial perfusion image generating system, comprising: the interim image acquisition unit that obtains with the radiography CT view data of electrocardiogram synchronous collection when the concentration of contrast agent is considered to constant in person under inspection's cardiac muscle part; And the blood-flow image generating unit that produces blood-stream image by the CT value that from the radiography CT view data of obtaining by image acquisition unit, deducts cardiac muscle.
Produce myocardial perfusion imaging in the short period of time according to this X ray CT device of the present invention and myocardial perfusion image generating system, reduce to the injection rate of person under inspection's contrast agent simultaneously, and x-ray dose.
Description of drawings
Fig. 1 illustrates the allocation plan of X ray CT device according to embodiments of the present invention;
Fig. 2 is in explanation person under inspection's the heart, in the cardiac muscle, and the figure of the behavior model of coronary artery interimage agent;
Fig. 3 is to use parameter to represent the figure of model illustrated in fig. 2 conceptually;
Fig. 4 is explanation because use contrast medium injector contrast agent illustrated in fig. 1 to inject to person under inspection's continuous static, the figure that the time-concentration of contrast agent changes in coronary artery and the cardiac muscle part;
Fig. 5 is the flow chart of the process instance of explanation when using X ray CT device illustrated in fig. 1 to produce myocardial perfusion imaging;
Fig. 6 is that explanation simplifies the figure that handles the image example that obtains by using X ray CT device illustrated in fig. 1 to make cardiomyography CT view data stand matrix;
Fig. 7 is explanation use X ray CT device illustrated in fig. 1 produces myocardial perfusion imaging from cardiomyography CT view data a process, and the figure of the myocardial perfusion imaging that obtains;
Fig. 8 is the figure that the inclination cross sectional image example that is obtained by the myocardial perfusion imaging cross section conversion process of using X ray CT device illustrated in fig. 1 is described;
Fig. 9 is explanation by the figure of the image example that uses synthetic myocardial perfusion imaging of X ray CT device illustrated in fig. 1 and myocardium image and obtain; And
Figure 10 is that explanation is by being provided with the figure of the blood-stream image example that display condition shows automatically on the image-display units of X ray CT device illustrated in fig. 1.
The specific embodiment
To be described in greater detail below in conjunction with appended drawings reference implementation scheme now according to X ray CT device of the present invention and myocardial perfusion image generating system.
Fig. 1 illustrates the allocation plan of X ray CT device according to embodiments of the present invention.X ray CT device 1 comprises gantry unit 2 and computer equipment 3.Gantry unit 2 comprises X-ray tube 4, high-voltage generator 5, X-ray detector 6, DAS (data-acquisition system) 7, contrast medium injector 8, and electrocardiograph 9.X-ray tube 4 and X-ray detector 6 are installed in the position facing each other that is clipped in the middle with not the showing in the rotating ring of high-speed and continuous rotation, with person under inspection P.
Has the function that contrast agent is injected into continuously person under inspection P according to some condition by the contrast medium injector of controlling from the control signal of computer equipment 38.Contrast medium injector 8 can be controlled the amount and the concentration of the contrast agent that is injected into person under inspection P based on the behavior of person under inspection P interimage agent.
Fig. 2 is in explanation person under inspection's the heart, in the cardiac muscle, and the figure of the behavior model of coronary artery interimage agent.In person under inspection P, the aortic bifurcation of Xian Shiing does not become coronary artery 10, and coronary artery 10 further is branched into capillary tube 11.Capillary tube 11 is inserted in the cardiac muscle 12, and cardiac muscle 12 comprises capillary tube 11 and myocardial cell 13.Myocardial cell 13 comprises the zone that is called framework 14, and is configured to make blood to shift out by shift-in between framework 14 and capillary tube 11.
Therefore, when contrast agent was injected into person under inspection P, contrast agent imported to coronary artery 10 with blood from large artery trunks, and imported to capillary tube 11 from coronary artery 10.In addition, when contrast agent flows in capillary tube 11 with blood, and when arriving myocardial cell 13, the framework 14 of the part of contrast agent in capillary tube 11 flows to myocardial cell 13.And the part of mobile blood flows out myocardial cell 13 and enters capillary tube 11 once more in the framework 14 in myocardial cell 13.
Therefore, in large artery trunks or coronary artery 10 inner bloods in the concentration of contrast agent and myocardial cell 13 or capillary tube 11 inner bloods concentration of contrast agent show different values, and moving because of contrast agent along with the time changes.The concentration of contrast agent is by determining when contrast agent transition constant and transition constant when contrast agent framework 14 in myocardial cell 13 flows to the capillary tube 11 the framework 14 time in capillary tube 11 flows to myocardial cell 13 in each part inner blood of person under inspection P.
More particularly, among the let us hypothesis time t in left ventricle inner chamber or the coronary artery concentration of contrast agent be Ca (t), the zone that is included in the cardiac muscle 12 is the unit area, wherein cardiac muscle 12 comprises capillary tube 11 and myocardial cell 13, the concentration (mean concentration of contrast agent in capillary tube 11 and the myocardial cell 13) of blood interimage agent is Cmyo (t) in the cardiac muscle 12, transition constant when the framework 14 of contrast agent in capillary tube 11 flows to myocardial cell 13 is K1, and the transition constant when contrast agent flows out in the framework 14 of capillary tube 11 in myocardial cell 13 is k2, and Ca (t) and Cmyo (t) are determined by transition constant K 1 and transition constant k 2.
Fig. 3 is to use parameter to represent the figure of model illustrated in fig. 2 conceptually.As shown in Figure 3, when having concentration C a (t) and moving to the framework 14 of myocardial cell 13 from capillary tube 11, have concentration C myo (t) and move to the capillary tube 11 from the framework 14 of myocardial cell 13 at t sometime with the contrast agent of transition constant k 2 proportional amounts with the contrast agent of transition constant K 1 proportional amount.Subsequently, moving afterwards, the concentration C a (t) and the concentration C myo (t) of contrast agent are determined by transition constant K 1 and transition constant k 2.
Therefore, the concentration C myo (t) of t cardiac muscle 12 interimage agent sometime can be represented by the amount of mobile contrast agent in framework 14 and the difference that flows out between the amount of contrast agent of framework 14, thereby satisfies following expression (1).
On the other hand, before this, known when contrast agent is injected in the person under inspection P according to certain condition statically that the concentration of contrast agent is thought constant in coronary artery and myocardium 12 inner bloods.
Fig. 4 is explanation because use contrast medium injector 8 contrast agent illustrated in fig. 1 to inject to person under inspection's continuous static, the figure that the time-concentration of contrast agent changes in coronary artery and the cardiac muscle part.
In Fig. 4, vertical axis is represented the concentration C of contrast agent, and trunnion axis express time t.And solid line is the data that change the time of indication coronary artery interimage agent concentration Ca (t), and dotted line is the data of indicating the time variation of the myocardium part interimage agent concentration Cmyo (t) that is made of myocardial cell 13 and capillary tube 11.
As shown in Figure 4, for example, if contrast agent is with injection rate x1[cc/sec] inject continuously at first t1 second, contrast agent is with injection rate x2[cc/sec then] inject continuously next t2 second, it is obtained that the concentration C myo (t) that the concentration C a (t) of coronary artery interimage agent is considered to constant interval T 1 and the agent of myocardial region interimage is considered to constant interval T.In this example, the static injection with injection rate 3cc/sec carried out 20 seconds, carried out 30 seconds with injection rate 1.5cc/sec subsequently.
Therefore, if the X ray CT data are considered to constant interval T 1 and electrocardiogram synchronous collection at the concentration C myo of myocardial region interimage agent (t), blood-stream image uses easily and collects X ray CT data afterwards, produces with various types of processing.Therefore, contrast medium injector 8 is configured, be injected in the person under inspection P so that will have the contrast agent of the per time amount of pre-determining speed according to certain condition, and the concentration C a (t) and the concentration C myo (t) of acquisition coronary artery and the agent of myocardium part interimage are considered to constant state.
Note, inject the condition of contrast agent and rule of thumb determine, make the concentration C a (t) of coronary artery interimage agent during the X ray CT data collection, become constant, so there are some difference in injection rate.The recommendation condition that contrast agent is static when injecting for example injection rate at document " Study of Optimal Contrast Examination Method in Herical ScanningCT " by Atsusi Yamachi and Tadashi Wako for example, Japan-Germany MedicalReports Vol.40 No.2,1995 (" researchs of the best contrast examination method among the helical scanning CT " of Atsusi Yamachi and Tadashi Wako, Japan-German medical report, Vol.40No.2,1995) the middle description.
But, there is certain situation, in fact the interval T 2 that wherein shows the indefinite concentration C a (t) of coronary artery interimage agent exists, as shown in Figure 4.Even in these cases, if the variation of the time of coronary artery interimage agent concentration Ca (t) is considered to constant, and comprise that linear state is satisfied, this can be used for the generation of blood-stream image, therefore, inject the condition of contrast agent and use contrast medium injector 8 to regulate, make the time of coronary artery interimage agent concentration Ca (t) become constant.
On the other hand, electrocardiograph 9 is connected to the electrode that does not show, this electrode is connected to person under inspection P.Electrocardiograph 9 has detection via the ECG signal (ECG signal) of electrode from person under inspection P, produces the electrocardiogram of person under inspection P from detected ECG signal, and it is provided to the function of computer equipment 3.
High-voltage generator 5 is configured, so that according to from the control signal of computer equipment 3, synchronously provide tube current or tube voltage to X-ray tube 4 with electrocardiogram, and use X-ray detector 6 to detect the X ray that sends to person under inspection P, constant or when having linearity as the concentration C myo (t) of coronary artery and the agent of myocardium part interimage and Ca (t).In addition, the x-ray detection signal that is detected by X-ray detector 6 is provided to DAS 7 so that digitized, and is provided to computer equipment 3.
And, image processing equipment 15 comprises as control core unit 19, to convert the pretreatment unit 20 of data for projection from the initial data of DAS 7 outputs to via proofreading and correct to handle to wait, be used to store the memory element 21 of data for projection, be used for rebuilding the image reconstruction unit 22 of CT view data from data for projection, be used to store the memory device 23 of CT view data, and be used for reading the CT view data so that produce the myocardial perfusion image generating system of myocardial perfusion imaging from memory device 23.
Myocardial perfusion image generating system 24 comprises image acquisition unit 24a, slice thickness adder unit 24b, and matrix simplifies unit 24c, mask process unit 24d, blood-flow image generating unit 24e, inclination cross section converting unit 24f, image synthesis unit 24g, and display processing unit 24h.
Slice thickness adder unit 24b has the view data from image acquisition unit 24a reception cardiomyography CT, and radiography CT value addition between the contiguous slices or average this are worth, thereby reduces the function of the resolution of radiography CT view data on the slice direction.
Matrix simplifies unit 24c and has the view data from image acquisition unit 24a reception cardiomyography CT, and makes radiography CT value stand addition and average, thereby reduces the function of the matrix of cardiomyography CT view data.
Blood-flow image generating unit 24e has the function of generation by the blood-stream image in the flow region of mask process unit 24d extraction.Now, the method for generation blood-stream image will be described.
As shown in Figure 4, if the concentration C myo (t) of myocardium part interimage agent is considered to constant, expression formula (1) left side vanishing is so expression formula (2) can obtain.
Rewriteeing expression formula (1) from expression formula (2) is expression formula (3),
K1·Ca(t)-k2·Cmyo(t)＝0 (3)
In addition, revise expression formula (3) and obtain expression formula (4).
In expression formula (4), if the concentration C a (t) of coronary artery interimage agent is considered to constant, do not having necrosis for example not have blood flow to arrive under the situation of cardiac muscle part, in the several hrs, cardiac muscle is alive after about the patient's morbidity with normal chest pain, and definite k2 is in normal range, therefore, it is constant that k2 also is considered to, and same Ca (t) is the same, and transition constant K 1 is proportional with the concentration C myo (t) of myocardium part interimage agent, as shown in expression formula (5).
K1∝Cmyo(t) (5)
In addition, it is E that the value of mark (extraction mark) of blood flow concentration interimage agent represent in order, and is F as the hemoperfusion [ml/100g/min] of rate of blood flow in the unit interval Unit Weight that pours into index, and known transition constant K 1 has the relation of K1=E * F.
Therefore, as shown in expression formula (6), the concentration C myo (t) of myocardium part interimage agent is proportional with myocardium part inner blood perfusion F.
Cmyo(t)∝F (6)
That is to say the relative value of concentration C myo (t) the indication hemoperfusion F of known myocardium part interimage agent.Therefore, if the concentration C myo (t) of myocardium part interimage agent can obtain, the relative value of hemoperfusion F can know.
Now, equal summation by the CT value of injecting the cardiomyography CT view data that contrast agent obtains as the CT value of the image of the only myocardium CT value of cardiac muscular tissue's composition and contrast agent composition.Therefore, if only myocardium partial C T value deducts from cardiomyography CT view data, the concentration C myo (t) that has with the myocardium part interimage agent of the proportionate relationship of the CT value of the image of contrast agent composition can obtain.
Therefore, blood-flow image generating unit 24e comprises by deducting the only CT value of cardiac muscle in the cardiomyography CT view data from the blood flow zone of being extracted by mask process unit 24d, and the image of contrast agent composition that produces the relative value who represents hemoperfusion F is as the function of blood-stream image.
Notice that if the concentration C a (t) of coronary artery interimage agent is not considered to constant, expression formula (5) can not derive from expression formula (4).But, if the variation of the time of the concentration C a (t) of coronary artery interimage agent is constant, if perhaps between the concentration of contrast agent and CT value, exist linear, correction coefficient obtains based on the time rate of change of this coronary artery interimage agent concentration, and the image of contrast agent composition can use the correction coefficient of acquisition to proofread and correct.For example, as shown in expression formula (7), let as assume that with the ratio between the concentration C a (t) of the concentration C a (t) of the coronary artery of t0 sometime interimage agent for referencial use and the agent of time t coronary artery interimage be correction coefficient alpha (t), and proofread and correct can be by carrying out with the CT of the image of contrast agent composition is on duty with correction coefficient alpha (t).
α(t)＝Ca(t)/Ca(t0) (7)
Therefore, blood-flow image generating unit 24e comprises if the concentration C a (t) of coronary artery interimage agent is non-constant, obtains correction coefficient alpha (t) so that proofread and correct the function of the image of contrast agent composition.
Inclination cross section converting unit 24f has the cross section of conversion by the myocardial blood flow image of blood-flow image generating unit 24e generation, and produces the cross sectional image of any cross-section, and for example cardiac muscle vertically is used as the function of its circular cross section image.
And, when being configured to box lunch display condition for images is set, display processing unit 24h on image-display units 16, shows to be used to the image of indicating display condition to be provided with, also so that obtain the indication of display condition for images from input block 17.
Suitably the example of display condition for images comprises the lower limit that is set to pixel value to be shown by the CT value of cardiac muscle, and the upper limit that the value that will obtain by the CT value addition of the contrast concentration Cmyo (t) in the cardiac muscle part and cardiac muscle is set to pixel value to be shown optionally shows the only display packing of blood-stream image, and be used for and the corresponding color of each pixel value show the CT value that is positioned at cardiac muscle and by with cardiac muscle partly contrast concentration Cmyo (t) and the value that obtains of myocardium CT value addition between the display packing of part of scope.In this case, a kind of scheme can be carried out, and wherein the upper limit of pixel value can fine be regulated because of default value by receiving indication information from input block 17.
Therefore, display processing unit 24h may comprise when carrying out gradation conversion and tone conversion at least, based on the corresponding value of myocardium part and with the corresponding value of cardiac muscle, it is by the contrast agent radiography, the function of the value of window position is set, perhaps may comprises when carrying out gradation conversion and tone conversion at least the value of window position is set, so as to emphasize to have with the corresponding value of myocardium part and with the corresponding value of cardiac muscle, it is by the contrast agent radiography, between the function of pixel of value.
Next, the operation of X ray CT device 1 will be described.Fig. 5 is the flow chart of the process instance of explanation when using X ray CT device 1 illustrated in fig. 1 to produce myocardial perfusion imaging, and wherein the reference character that is made of character S and numeral is represented each step in the flow chart.
At first, in step S1, the control of the control signal of contrast medium injector 8 origin self-scanning control appliances 18, contrast agent is injected into the person under inspection P, as shown in Figure 4 from contrast medium injector 8 continuously according to certain condition.
Therefore, the IC contrast concentration Ca (t) of person under inspection P becomes concentration or time rate of change is considered to constant state.And the contrast concentration Cmyo (t) in the cardiac muscle part becomes concentration or time rate of change is considered to constant state.
Next, in step S2, the contrast concentration Cmyo (t) of the radiography CT view data of whole cardiac muscle in the cardiac muscle part is considered to synchronously collect with electrocardiogram in constant period.
More particularly, electrocardiograph 9 detects the ECG signal via the not show electrode that is connected to person under inspection P.Electrocardiograph 9 obtains electrocardiogram and it is provided to scanning controller 18.Scanning controller 18 provides control signal to high-voltage generator 5 based on the electrocardiogram that is obtained by electrocardiograph 9.Thereby high-voltage generator 5 synchronously provides tube current and tube voltage to X-ray tube 4 with electrocardiagraphic wave, and X ray emits on the person under inspection P.
X-ray detector 6 detects the X ray that emits on the person under inspection P and pass person under inspection P.Be provided to DAS 7 from the x-ray detection signal of X-ray detector 6 outputs, digitized there initial data produces.DAS 7 is provided to pretreatment unit 20 with the initial data that produces, and pretreatment unit 20 makes initial data stand for example various types of corrections of pretreatment to handle, so that convert initial data to data for projection.The data for projection that is obtained by pretreatment unit 20 temporarily is stored in the memory element 21, is provided to image reconstruction unit 22 then.Image reconstruction unit 22 is rebuild the CT view data from data for projection, and the CT Imagery Data Recording of rebuilding and being stored in the memory device 23.
Notice that contrast agent is injected into person under inspection P, so the CT view data that is stored in the memory device 23 becomes radiography CT view data.CT image and electrocardiogram are synchronously collected, so cardiomyography axial cross section image can be in myocardial contraction or each cardiac muscle contemporaneity acquisition partly in expansionary phase.Image acquisition unit 24a obtains the radiography CT view data that is stored in the memory device 23, and it is provided to myocardial perfusion image generating system 24.
In addition, the axial cross section image set obtains in cardiac muscle each section with one-period from a series of cycles that are retracted to expansion in case of necessity, is used for the cardiac muscle diagnosis.About various types of images of cardiac muscle, minor axis cross sectional image for example, major axis horizontal X ray computer tomography figure, and the vertical tomography X figure of major axis can obtain because of the cross section conversion of each axial cross section image of obtaining.
Myocardial perfusion image generating system 24 can and stand from such collection to produce myocardial perfusion imaging the cardiomyography CT view data of various cross sections conversion.
Now, attempt to produce myocardial perfusion imaging and the resolution that do not change cardiomyography CT view data may allow effect of noise.Therefore, cardiomyography CT view data stands resolution and reduces to handle in case of necessity, as producing the pretreatment of myocardial perfusion imaging.
More particularly, in step S3, slice thickness adder unit 24b receives cardiomyography CT view data from image acquisition unit 24a, and the radiography CT value in addition or the average adjacent a plurality of sections, thereby the resolution of carrying out radiography CT view data on slice direction reduces to handle.For example, the normally about 0.5mm of the slice thickness of cardiomyography CT image, so in order to use cardiomyography CT view data to produce myocardial perfusion imaging, the resolution on the slice direction reduces, wherein slice thickness becomes about 3mm, 5mm, or 10mm.
In addition, in step S4, matrix simplifies the radiography CT value addition of unit 24c with cardiomyography CT view data in each section, and is perhaps that it is average, simplifies processing thereby carry out matrix.
Fig. 6 is that explanation simplifies the figure that handles the image example that obtains by using X ray CT device illustrated in fig. 1 to make cardiomyography CT view data stand matrix.
In Fig. 6, (a) the explanation matrix simplifies the cardiomyography CT view data before handling, and (b) illustrates that matrix simplifies the cardiomyography CT view data after handling.
As shown in (a), the cardiomyography CT view data before matrix simplifies and handles is 664 matrixes for example, and its per unit pixel cell size is 0.3mm.Use this 664 matrix cardiomyography CT view data, near adjacent or radiography CT value addition or average, and the per unit pixel cell size is that the 256 matrix cardiomyography CT view data of 0.778mm are obtained, as shown in (b).Notice that the processing sequence that slice thickness addition processing and matrix simplify between the processing can be opposite, just choose at random.
Next, in step S5, when resolution reduced to finish dealing with, mask process unit 24d made cardiomyography CT view data stand mask, thereby extracted the zone that comprises blood flow from cardiomyography CT view data.
In step S6, deduct the CT value of cardiac muscle in the radiography CT view data the blood-flow image generating unit 24e zone that blood flow exists after being included in mask process, and myocardial perfusion imaging produces subsequently.
Fig. 7 is explanation use X ray CT device illustrated in fig. 1 produces myocardial perfusion imaging from cardiomyography CT view data a process, and the figure of the myocardial perfusion imaging that obtains.
In Fig. 7, (a) be the cardiomyography CT view data in each section after resolution reduces to handle.Mask process unit 24d for example makes the cardiomyography CT view data shown in (a) stand mask, for example comprises shown in (b) that the zone of blood flow is extracted.Here, (b) be stand mask make the CT value become to concentrate on myocardium of left ventricle 0 and 150 between example.The extraction zone that comprises blood flow can be discerned from (b).
In addition, as shown in (b), blood-flow image generating unit 24e carries out myocardium CT value deducting from the radiography CT view data of extracting, thereby obtains the image of contrast agent composition.And, (c) be the image of the contrast agent composition that obtains by subtraction process because of blood-flow image generating unit 24e, myocardial perfusion imaging example just, wherein Xin Ji CT value is set to 34, and deducts from radiography CT view data without exception.This calculates and remove myocardium composition from image.
If IC contrast concentration Ca (t) is not considered to constant, blood-flow image generating unit 24e obtains the correction coefficient alpha (t) as shown in expression formula (7), and the image and the correction coefficient alpha (t) of contrast agent composition are multiplied each other, so that correcting image.
The myocardial perfusion imaging of Chan Shenging is used for diagnosis like this.In addition, in case of necessity, myocardial perfusion imaging stands various types of processing of being convenient to diagnose.
For example, in step S7, inclination cross section converting unit 24f makes the cross section of myocardial perfusion imaging stand conversion process, so that produce the inclination cross sectional image of myocardium fusion image.Notice that this step S7 can carry out after step S2.
Fig. 8 is the figure that the inclination cross sectional image example that obtains because of the myocardial perfusion imaging cross section conversion process of using X ray CT device illustrated in fig. 1 is described.
Cardiac muscle has the spheroid shape that comprises long and minor axis, helps to be convenient to diagnosis so convert myocardial perfusion imaging to its circular cross section image on cardiac muscle is vertical, as shown in Figure 8.
In addition, the convenience during diagnosis can improve to show by synthetic myocardial perfusion imaging and myocardium image.In this case, for will with the synthetic myocardium image of myocardial perfusion imaging, use matrix among the step S4 to simplify to handle and step S3 in section between the myocardium image of high-resolution before the addition of radiography CT value more effective.
Therefore, in step S8, image synthesis unit 24g simplifies the high-resolution cardiac muscle image before the addition of radiography CT value between processing and the section from image acquisition unit 24a receiving matrix, and generation and the synthetic image of myocardial perfusion imaging.
Fig. 9 is explanation by the figure of the image example that uses synthetic myocardial perfusion imaging of X ray CT device illustrated in fig. 1 and myocardium image and obtain.
In Fig. 9, (a) by image acquisition unit 24a obtain, matrix simplify handle and section between high-resolution cardiac muscle image before the addition of radiography CT value, and (c) be the myocardial perfusion imaging of the myocardium image acquisition after resolution reduces to handle.For example the fusion image of cardiac muscle of indication shown in (b) and blood flow can obtain with the low resolution myocardial perfusion imaging (c) by the high-resolution cardiac muscle image shown in synthetic (a).Therefore, synthetic myocardium image and blood-stream image are convenient to diagnosis.
The blood-stream image that each image is for example produced by blood-flow image generating unit 24e, the inclination cross sectional image that produces by inclination cross section converting unit 24f, and the composograph that is produced by image synthesis unit 24g is provided to display processing unit 24h.Subsequently, display processing unit 24h will be used to show that the picture signal of each image is provided to image-display units 16 with display image signals.
Notice that the user can be used to show the automatic setting of the display condition of each image by input block 17 indications.Display processing unit 24h will show that the picture signal of electronic button is provided to image-display units 16, for example.
Figure 10 is that explanation is by being provided with the figure of the blood-stream image example that display condition shows automatically on the image-display units of X ray CT device illustrated in fig. 1.
As shown in Figure 10, radiography CT image 30, automatic (AUTO) button 31 that the indicated number condition is provided with automatically, and brightness degree 32 shows on the screen of image-display units 16.That is to say that Figure 10 explanation shows blood-stream image so that by the example under the situation of gray level recognition image according to brightness.
When the user pressed automatically (AUTO) button 31 by operation input block 17, input block 17 was indicated being provided with automatically of display condition and is provided to display processing unit 24h.Respond this indication, display processing unit 24h is provided with higher limit WU and the lower limit WL that suitable value is a brightness degree (window position), and the width W W of window position between higher limit and the lower limit, automatically to show blood-stream image.
Say that more specifically let as assume that myocardium CT value (about 34) is A, the concentration C myo (t) of myocardium part interimage agent is B, the arbitrary value of fine adjustments is β, and for example WU=A+B and WL=A+ β (therefore, WW=B-β) are set, perhaps WL=A+ β, and WW=A+ β+B can carry out.Therefore, brightness degree is set to be suitable for show the value of the blood-stream image of cardiac muscle part, and the myocardial blood flow image as shown in Figure 10 according to brightness with gray level display.
At this moment, the value the value between WU and WL by convert to certain brightness for example black remove.As selection, different gradation conversion character be provided between WU and the WL part and between WU and WL part so that emphasize value between WU and the WL for demonstration.Note, preferably, carry out that gradation conversion is handled so that make the user can visually discern less blood flow part with the part of black (brightness value zero or extremely low brightness value) show value WL.
Attention is in Figure 10, and the myocardial blood flow image shows with overlapping other images thereon.A kind of scheme can be carried out, and the value of wherein determining display condition is A for example, and B and β can fine regulate by operation input block 17.The value of A is not limited to the CT value, but can change according to clinical purpose.Value B can be defined as default value according to experiment.
In addition, show that with color the scope between WU and the WL can allow the user visually to discern the blood-stream image of cardiac muscle part.If carry out colored the demonstration, colored gray-scale displayed can visually be divided into 16 grades according to level to be identified, perhaps can be divided into 16 grades or more, perhaps 16 grades or still less, for example.
If for example activate the application-specific of carrying out myocardial blood flow demonstration or myocardial blood flow analysis etc. by the application program that utilizes the carries out image display process, (AUTO) button 31 can show automatically.As selection, the hardware keys that is made of specific hardware can be provided on the input block 17 as automatic (AUTO) button 31.
The process in Fig. 5 shown in the flow chart, the order of each step can change, and perhaps the part of step can be omitted, to produce myocardial perfusion imaging.Example comprises process: S1 → S2 → S3 → S4 → S6 → S7 → S5 → S8, process: S1 → S2 → S7 → S6 → S8, and process: S1 → S2 → S7 → S3 → S4 → S5 → S6 → S8.
Use the X ray CT device 1 and the myocardial perfusion image generating system 24 of configuration like this, the coronarography CT data and the cardiomyography CT data of collecting because of the continuous injection of contrast agent under certain condition comprise about the information as the heart muscle perfusion of blood perfusion index in the cardiac muscle part, make image form by carrying out about the information of heart muscle perfusion from coronarography CT data and cardiomyography CT extracting data via date processing.More particularly, X ray CT device 1 and myocardial perfusion image generating system 24 are carried out contrast agent and are injected to the static state of person under inspection P, in cardiac muscle part and coronary artery, obtain cardiomyography CT image between flow periods with constant density Ca (t) at contrast agent, and the distributed image of contrast agent composition is used as the blood perfusion image of indicating relative hemoperfusion F, because the distributed image of the contrast agent composition that obtains of CT value by deducting cardiac muscle from the cardiomyography CT image that obtains has proportional relation with blood perfusion F.
Therefore, X ray CT device 1 and myocardial perfusion image generating system 24 produce myocardial perfusion imaging in the short period of time, further reduce simultaneously about person under inspection's contrast agent charge velocity and because of the dosage of X ray.In other words, up to now, the scanning execution independently of obtaining the scanning of myocardium image and obtaining blood flow information, but X ray CT device 1 and myocardial perfusion image generating system 24 can be from the information that is obtained by the scanning of obtaining myocardium image, coronarography CT view data for example, obtain blood flow information in the cardiomyography CT view data etc., and do not increase the scanning of obtaining blood flow information.Therefore, myocardial perfusion imaging can produce in the short period of time, reduces person under inspection's the x-ray bombardment period and the injection rate of contrast agent because of scanning times simultaneously.
In addition, in routine inspection, become available,, determine the patient strategy apace by CT examination only so the present invention allows the user in emergency circumstances cardiopathic according to the impossible heart muscle perfusion inspection of routine because of CT.
Note, use above-mentioned embodiment, blood-stream image produces by the CT value that only deducts cardiac muscle from cardiomyography CT view data, but blood-stream image may be by deducting from cardiomyography CT view data by adding/subtract/take advantage of/remove about certain value of myocardium CT value and the acquisition value, just obtains certain and be worth and produce from the CT value of cardiac muscle.
Claims (17)
1. X ray CT device, be used to radiate X ray to the person under inspection in case scanning person under inspection and rebuild image in the person under inspection based on the data for projection that obtains comprise:
Image generation unit is considered under the constant state in the myocardium partly concentration of contrast agent of the person under inspection who injects contrast agent continuously, produces image based on data for projection; And
Blood-flow image generating unit assigns to produce blood-stream image by the one-tenth of removing cardiac muscular tissue from the myocardial region part of the image that produced by image generation unit.
2. according to the X ray CT device of claim 1, also comprise definite territory element, be used for determining the myocardial region part of the image that produced by image generation unit, wherein blood-flow image generating unit is configured so that from by the composition of determining to remove the myocardial region part that territory element is determined cardiac muscular tissue.
3. according to the X ray CT device of claim 1, wherein image generation unit is configured so that produce blood-stream image by deduct the CT value that is equivalent to cardiac muscle from myocardial region partial C T image.
4. according to the X ray CT device of claim 1, also comprise display processing unit, when carrying out at least that gradation conversion is handled and during the tone conversion process, based on by the corresponding value of myocardium part of contrast agent radiography with the corresponding value of cardiac muscle own the value of window position is set.
5. according to the X ray CT device of claim 1, also comprise display processing unit, when carrying out at least gradation conversion and handle, based on by the corresponding value of myocardium part of contrast agent radiography with the corresponding value of cardiac muscle itself value of window position is set.
6. according to the X ray CT device of claim 1, also comprise display processing unit, when carrying out at least that gradation conversion is handled and the value of window position be set during the tone conversion process, so as to emphasize to have with by the corresponding value of myocardium part of contrast agent radiography and and myocardium corresponding value own between the pixel of value.
7. according to the X ray CT device of claim 1, also comprise display processing unit, when gradation conversion is handled the value of window position is set when carrying out at least, so as to emphasize to have with by the corresponding value of myocardium part of contrast agent radiography and and the corresponding value of cardiac muscle own between the pixel of value.
8. X ray CT device comprises:
Contrast medium injector, the concentration that contrast agent is injected among the person under inspection and obtains contrast agent in person under inspection's cardiac muscle part continuously is considered to constant state;
The image collection unit, the concentration of contrast agent is considered to synchronously collect radiography CT image with electrocardiogram during constant in cardiac muscle part; And
Blood-flow image generating unit produces blood-stream image by the CT value that deducts cardiac muscle from the radiography CT view data of cardiac muscle part.
9. X ray CT device according to Claim 8, wherein blood-stream image is represented the rate of blood flow in the cardiac muscle.
10. X ray CT device according to Claim 8 also comprises the slice thickness adder unit, by the radiography CT value phase Calais between the radiography CT view data contiguous slices being reduced the resolution of radiography CT view data on the slice direction.
11. X ray CT device according to Claim 8 comprises that also matrix simplifies the unit, the radiography CT value addition by making radiography CT view data and on average reduce resolution to reduce matrix size.
12. X ray CT device according to Claim 8, wherein blood-flow image generating unit is configured, so that if the time rate of change of contrast concentration coronarius is considered to constant, time rate of change based on contrast concentration coronarius obtains correction coefficient, and proofreaies and correct the CT value of blood-stream image because of the correction coefficient that obtains.
13. X ray CT device according to Claim 8 also comprises inclination cross section converting unit, the cross section by the conversion blood-stream image produces cross sectional image in any cross section.
14. X ray CT device according to claim 10, also comprise the image synthesis unit, synthetic and the overlapping blood-stream image that produces from have the radiography CT view data that reduces resolution reduces the radiography CT view data of resolution before with having, so that show by the arbitrary value same position place on screen that regulates two width of cloth images.
15. X ray CT device according to claim 11, also comprise the image synthesis unit, synthetic and the overlapping blood-stream image that produces from have the radiography CT view data that reduces resolution reduces the radiography CT view data of resolution before with having, so that show by the arbitrary value same position place on screen that regulates two width of cloth images.
16. a myocardial perfusion image generating system comprises:
Image acquisition unit is considered to obtain image under the constant state in the continuous myocardium partly concentration of contrast agent of injecting the person under inspection of contrast agent; And
Blood-flow image generating unit assigns to produce blood-stream image by the one-tenth of removing cardiac muscular tissue from the myocardial region part of the image that obtained by image acquisition unit.
17. a myocardial perfusion image generating system comprises:
Image acquisition unit, the interim radiography CT view data of obtaining with the electrocardiogram synchronous collection when concentration of contrast agent is considered to constant in person under inspection's cardiac muscle part; And
Blood-flow image generating unit produces blood-stream image by the CT value that deducts cardiac muscle from the radiography CT view data of being obtained by image acquisition unit.
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| US8626263B2 (en) * | 2006-04-13 | 2014-01-07 | General Electric Company | Methods and apparatus for relative perfusion and/or viability |
| JP5091644B2 (en) * | 2006-12-04 | 2012-12-05 | 株式会社東芝 | X-ray computed tomography apparatus and medical image processing apparatus |
| JP5449651B2 (en) * | 2007-03-09 | 2014-03-19 | 株式会社東芝 | X-ray CT apparatus and myocardial perfusion information generation system |
| WO2008139344A1 (en) * | 2007-05-10 | 2008-11-20 | Koninklijke Philips Electronics N.V. | Model-based spect heart orientation estimation |
| JP5234905B2 (en) * | 2007-11-20 | 2013-07-10 | 東芝メディカルシステムズ株式会社 | X-ray CT apparatus and myocardial perfusion image generation system |
| JP5558672B2 (en) * | 2008-03-19 | 2014-07-23 | 株式会社東芝 | Image processing apparatus and X-ray computed tomography apparatus |
| JP5433299B2 (en) * | 2009-05-18 | 2014-03-05 | 株式会社東芝 | Medical diagnostic imaging equipment |
| JP5610761B2 (en) * | 2009-12-16 | 2014-10-22 | キヤノン株式会社 | X-ray image processing apparatus, X-ray image processing system, X-ray image processing method, and computer program |
| JP6104166B2 (en) * | 2011-09-27 | 2017-03-29 | 株式会社日立製作所 | X-ray CT apparatus and image correction method |
| CN107929882A (en) * | 2017-12-28 | 2018-04-20 | 赵刚 | A kind of Multifunctional heart vascular interventional treatment integrated device |
| CN111904450B (en) * | 2020-09-07 | 2023-11-07 | 北京永新医疗设备有限公司 | Extraction method, device and system for center of left ventricle and region of interest |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4210121C1 (en) * | 1992-03-27 | 1993-04-29 | Siemens Ag, 8000 Muenchen, De | Medical X=ray diagnostic equipment - has sensor detecting speed of movement of organ, e.g. heart, with output signal being used to change pulse series frequency of pulsed radiation automatically |
| US20030069499A1 (en) * | 2001-03-19 | 2003-04-10 | Jean Lienard | Method and device for cardiac radiological examination |
| CN1413559A (en) * | 2001-10-16 | 2003-04-30 | 株式会社东芝 | Method and device for counting circultion exponent about local blood flow |
| US6628743B1 (en) * | 2002-11-26 | 2003-09-30 | Ge Medical Systems Global Technology Company, Llc | Method and apparatus for acquiring and analyzing cardiac data from a patient |
-
2005
- 2005-03-18 CN CNB2005100563553A patent/CN100462050C/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4210121C1 (en) * | 1992-03-27 | 1993-04-29 | Siemens Ag, 8000 Muenchen, De | Medical X=ray diagnostic equipment - has sensor detecting speed of movement of organ, e.g. heart, with output signal being used to change pulse series frequency of pulsed radiation automatically |
| US20030069499A1 (en) * | 2001-03-19 | 2003-04-10 | Jean Lienard | Method and device for cardiac radiological examination |
| CN1413559A (en) * | 2001-10-16 | 2003-04-30 | 株式会社东芝 | Method and device for counting circultion exponent about local blood flow |
| US20030097076A1 (en) * | 2001-10-16 | 2003-05-22 | Kyojiro Nambu | Method and apparatus for calculating index concerning local blood flow circulations |
| US6628743B1 (en) * | 2002-11-26 | 2003-09-30 | Ge Medical Systems Global Technology Company, Llc | Method and apparatus for acquiring and analyzing cardiac data from a patient |
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