JP2013000583A - Method for measuring position of movable object, and x-ray imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure a position of an object moving inside a blood vessel with high reliability, and to associate the position to the blood vessel.SOLUTION: A first X-ray image data set R1 related to a region of a living body including the blood vessel 26 containing a contrast medium in a first concentration are acquired before or after the movement of the movable object 24, a second X-ray image data set R2 including data related to the region are acquired in a state that the blood vessel 26 does not contain the contrast medium at all before or after the movement of the movable object, a third X-ray image data set R3a including data related to the region are acquired in the state that the blood vessel 26 des not contain the contrast medium at all during the movement of the movable object, a difference image data set Sa comprising the second X-ray image data set and the third X-ray image data set are calculated, data allocatable to the movable object are identified, data of the first X-ray image data set are allocated to data of the difference image data set, and the position of the movable object 24 inside the blood vessel 26 is measured based on the first X-ray image data set and the data allocatable to the movable object 24.

Description

  The present invention relates to a method for measuring a position of a movable object that absorbs X-rays more strongly than a living tissue in the process of moving in the blood vessel of the living body. The present invention also relates to an X-ray imaging apparatus having an X-ray tube, an X-ray detector, and an image processing unit.

  It is known to use x-rays to examine a patient's coronary vessels. In this case, normally, the administered contrast medium reaches the coronary blood vessel through the blood vessel, and the coronary blood vessel clearly appears in the X-ray image. In this way, information relating to the geometric shape or morphology of coronary vessels can be detected. However, information on the coronary vascular physiology is not available.

  In order to examine the inner wall of the blood vessel in more detail, it is known to carry out a method called IVUS (Intravascular Ultrasound) that uses a catheter that has an ultrasonic head and is introduced into the blood vessel. This method provides an ultrasonic tomographic image with high spatial resolution of the blood vessel inner wall. However, it is difficult to assign the ultrasonic image thus taken to a specific position of the catheter in the coronary blood vessel.

  In this connection, it is known to take an X-ray image when a catheter is placed at a starting position in a blood vessel. Estimate the respective position of the ultrasound head within the blood vessel at a particular point in time, with the vessel shape provided from the X-ray image and the known speed of drawing the catheter through the vessel while taking the ultrasound image with the catheter be able to.

  Alternatively, while the catheter is being pulled through the blood vessel, fluoroscopy may be performed continuously without contrast agent administration, that is, an X-ray image series may be taken. In this case, the respective position of the ultrasonic head in the X-ray image can be identified by the segmentation method. However, this method has the disadvantage that a clear identification of the catheter is not always possible. For example, other objects in the patient may have a contrast similar to an IVUS catheter, thus making clear identification difficult. Examples of this are transplanted tissue (e.g. components of cardiac pacemakers), surgical sutures (e.g. based on bypass surgery) or intravascular calcification.

  Since an X-ray image obtained by angiography using a contrast agent is taken at a different time from the X-ray image series during the movement of the catheter, the movement of the patient adversely affects the subsequent image adjustment, and both image data sets Correlation may be difficult. Often such movement is unavoidable if this movement is a movement caused in particular by breathing or heartbeat.

  An object of the present invention is to measure the position of an object moving in a blood vessel with higher reliability and relate it to the geometric shape of the blood vessel.

According to the present invention, this problem is a method of measuring the position of a movable object in a process in which the movable object that absorbs X-rays more strongly than the living tissue moves in the blood vessel of the living body,
a) obtaining a first X-ray image data set for at least one part of a living body at least partially comprising a blood vessel containing a contrast agent at a first concentration before or after movement of the movable object; ,
b) Second X-ray image data including data relating to the part in a state in which the blood vessel contains a contrast agent at a concentration lower than the first concentration or not at all after the movement of the movable object. A step in which the set is obtained;
c) During the movement of the movable object, at least one third X-ray image data set (including data relating to the region) is acquired with the blood vessel containing the contrast agent at the low concentration or not at all. And steps
d) The spatially assignable data values of the second X-ray image data set and the third X-ray image data set are subtracted from each other to obtain the second X-ray image data set and the third X-ray Calculating a difference image data set comprising image data sets;
e) performing a segmentation method on the difference image data set to identify data that can be assigned to the movable object;
f) assigning the data of the first X-ray image data set to the data of the difference image data set by determining a geometric assignment rule that can be given in advance (ie presettable);
g) measuring the position of the movable object within the blood vessel based on the first X-ray image data set and the data identified and assignable to the movable object;
It is solved by the position measuring method of the movable object having (claim 1).
The embodiment of the present invention relating to the position measuring method of the movable object is as follows.
Step c) follows steps a) and b) in time, and in step c), a plurality of third X-ray image data sets are acquired one after the other, and a plurality of third X-ray image data is acquired. The position of the movable object is measured according to steps d) to g) for each of the sets (claim 2).
-While acquiring at least one of the third X-ray image data sets, one other image data set relating to the internal space of the blood vessel is acquired by a movable object within the blood vessel (claim 3).
Another image data set is assigned to the position of the movable object whose position in the blood vessel has been measured (claim 4).
The movable object includes a catheter, and another image data set is acquired by intravascular ultrasound (Claim 5).
The blood vessel moves approximately periodically and at the same phase position of the periodic motion, the first X-ray image data set and the second X-ray image data set, and / or the first X-ray image data set and A third X-ray image data set and / or a second X-ray image data set and a third X-ray image data set are acquired.
The periodic movement is detected by a measurement unit, preferably an electrocardiogram detector, and the acquisition time points of the first X-ray image data set and / or the second X-ray image data set and / or the third X-ray image data set are It is determined based on data supplied from the measurement unit.
The blood vessel moves in response to the overlap of the first and second periodic movements, the first periodic movement is detected by the measurement unit, and the second periodic movements are successively more than one in time Spatial assignment of data values detected in step d) by obtaining a first X-ray image data set and / or a second X-ray image data set and / or a third X-ray image data set of And / or determining the geometrical assignment rule that can be given in advance in step f) is performed depending on the detected first and second spatial movements (claim 8).
Determining the allocation rule in step f) is to determine whether the first X-ray image data set and the second X-ray image data set and / or the third X-ray image data set and / or the difference image data set; This is performed by registration (claim 9).
Determining the assignment rule in step f) comprises the coordinate system assigned to the first X-ray image data set, the second X-ray image data set and / or the third X-ray image data set; Alternatively, it is performed by coordinate conversion with the coordinate system assigned to the difference image data set.
According to the present invention, there is provided an interface in an X-ray imaging apparatus having an X-ray tube, an X-ray detector, and an image processing unit for carrying out the method according to the present invention. The image processing unit is also solved by an X-ray imaging device which can be connected to a catheter for acquiring an image data set relating to the internal space of the blood vessel with respect to signal exchange (claim 11).

The method according to the present invention is used to measure the position of a movable object that absorbs X-rays more strongly than biological tissue in the process of moving in the blood vessel of the living body. The method comprises the following steps according to the invention:
a) obtaining a first X-ray image data set for at least one part of a living body at least partially comprising a blood vessel containing a contrast agent at a first concentration before or after movement of the movable object; ,
b) Second X-ray image data including data relating to the part in a state in which the blood vessel contains a contrast agent at a concentration lower than the first concentration or not at all after the movement of the movable object. A step in which the set is obtained;
c) During the movement of the movable object, at least one third X-ray image data set containing data relating to the part is acquired with the blood vessel containing the contrast agent at the low concentration or not at all. Steps,
d) A difference image data set composed of the second X-ray image data set and the third X-ray image data set is calculated, and at this time, the second X-ray image data set and the third X-ray image data set Subtracting mutually spatially assignable data values from each other;
e) performing a segmentation method on the difference image data set to identify data that can be assigned to the movable object;
f) assigning the data of the first X-ray image data set to the data of the difference image data set by determining a geometric assignment rule that can be given in advance (ie presettable);
g) measuring the position of the movable object within the blood vessel based on the first X-ray image data set and the data identified and assignable to the movable object;
Have

  In particular, the difference image data set is acquired before the movable object is identified by the segmentation method, thereby ensuring that no data about the object that can be mistakenly identified as the movable object is present in the difference image data set. . This is especially true for foreign objects that are stationary in time. Compared to these extraneous objects, the movable object appears clearly in the difference image data set during movement in the blood vessel and can be identified very easily by the automatic segmentation method. In this way, highly reliable position measurement of the movable object is possible.

  According to step f), since the data of the first X-ray image data set acquired by the contrast agent is uniquely associated with the positionable movable object by a geometrical assignment rule, By combining these complementary data sets, one meaningful composite data set can be created. In particular, the geometric shape of the blood vessel can be clearly determined from the first X-ray image data set acquired in step a). Since the movable object identified with very high reliability in steps b) to e) is associated with this geometric shape, a very accurate position measurement is possible in step g).

  Only in step a), in order to improve the visualization of the blood vessel, the blood vessel already contains contrast agent at the time of acquisition of the first X-ray image data set, but the second and third X-ray image data sets Since the acquisition is performed without such a contrast medium, the physiological burden on the patient can be significantly reduced. The overall X-ray dose received by the patient during the implementation of this method is also very low.

  Steps a) and b) are preferably carried out with the movable object not yet in the part. However, instead, the movable object may already be placed at the starting position in the part and not moved during acquisition of the second X-ray image data set. Step b) is preferably carried out without the presence of a contrast agent. Step c) is preferably carried out with the same contrast agent concentration as in step b).

  Particularly preferably, step c) follows steps a) and b) in time, and in step c) a plurality of third X-ray image data sets are acquired one after the other, after which a plurality of third x-ray image data sets are acquired. Further measurement of the position of the movable object is performed according to steps d) to g) for each of the X-ray image data sets. The first and second X-ray image data sets acquired in steps a) and b) constitute in particular the reference image data set, whereas a plurality of X-ray image data sets acquired in step c). Form an original measurement data set that is further processed using these reference image data sets. In particular, a static X-ray image is provided by the first and second X-ray image data sets, whereas a third X-ray image is acquired intermittently or continuously in fluoroscopy with a stroboscope series. In this way, the movement of the movable object in the blood vessel can be tracked very well. This is because each third X-ray image data set is assigned to any position of the movable object. It is particularly preferred that steps a), b) and c) are carried out one after the other in this order in time. However, step b) may be performed before step a).

  While acquiring at least one of the third X-ray image data sets, one other image data set relating to the internal space of the blood vessel may be acquired by a movable object in the blood vessel. In particular, one of a plurality of other image data sets can be uniquely assigned to each of the third X-ray image data sets. Since the plurality of third X-ray image data sets and the plurality of other image data sets exist in particular in relation to each other in time, a particularly meaningful composite measurement data set is generated. In particular, the other image data set is an image data set acquired by a method that does not use X-rays. In this case, a particularly meaningful complementary measurement data set can be used.

  The other image data set is assigned to the position of the movable object whose position is measured in the blood vessel. This embodiment is particularly advantageous when the position of the movable object within the blood vessel can be estimated at all or insufficiently by considering only the other image data sets themselves. In this case, in the method according to the invention, this missing position information is provided in particular by means of an X-ray image data set.

  Particularly preferred is that the movable object includes a catheter and that another image data set is acquired by intravascular ultrasound. In that case, the intravascular ultrasound method can provide data on the state of the inner wall of the blood vessel that cannot be obtained from the X-ray image data set. On the other hand, these ultrasonic data can be uniquely assigned to a specific blood vessel position. In this way, the physiological state of the inner wall of the blood vessel can be assigned to a specific part of the blood vessel. A particularly accurate medical diagnosis is possible.

  When the blood vessel moves substantially periodically, the first X-ray image data set and the second X-ray image data set, and / or the first X-ray image at the same phase position of the periodic movement. Preferably, a data set and a third X-ray image data set and / or a second X-ray image data set and a third X-ray image data set are acquired. In this way it is ensured that the parts of the physiological object detected in the first, second and / or third X-ray image data sets are identical, i.e. have matching coordinate systems. Errors caused by processing data from different X-ray image data sets that can be assigned to non-identical geometric locations are avoided.

  Preferably, a periodic movement is detected by the measurement unit and the time point for acquiring the first X-ray image data set and / or the second X-ray image data set and / or the third X-ray image data set Is determined based on data supplied from the measurement unit. The periodic movement is caused, for example, by the rhythmic pumping of the heart. The periodic movement can be detected by an electrocardiogram. In this case, an ECG (electrocardiogram) device is provided as a measurement unit. The ECG signal is used in particular as a timing pulse generator for acquisition of X-ray image data sets, thereby avoiding blurring of the image contour during acquisition.

  In addition to the inevitable movement of blood vessels due to heart pumping, movement due to patient breathing is also inevitable. Thus, if the blood vessel moves in response to the overlap of the first and second periodic motions, preferably the first periodic motion is detected by the measurement unit and the second periodic motion is sequential in time. To obtain a plurality of first and / or second and / or third X-ray image data sets. In doing so, the spatial assignment of the data values is preferably made in step d) in dependence on the detected first and second spatial movements. This can alternatively or additionally be used to determine a pre-given geometric assignment rule in step f). In particular, in this way, the first periodic motion can be separated from the second periodic motion and used individually in image processing. Thereby, an undesirable measurement error in the X-ray image data set due to the blood vessel motion can be avoided.

  Preferably, in step f), the determination of the allocation rule comprises the first X-ray image data set and the second X-ray image data set and / or the third X-ray image data set and / or the difference image data set. And is registered. Alternatively, or in addition, in step f), determining the assignment rules may include the coordinate system assigned to the first X-ray image data set, the second X-ray image data set, and / or the third X-ray. It may be performed by coordinate conversion between the image data set and / or the coordinate system assigned to the difference image data set. The latter alternative is particularly sufficient if the coordinate systems associated with the individual X-ray image data sets are all known. However, if all of these coordinate systems are not known, the same calculation as in the image registration method may be performed. In this way it is ensured that only data assigned to the same geometric position are actually processed with respect to each other. Therefore, position measurement can be performed with extremely high accuracy.

  An X-ray imaging apparatus according to the present invention includes an X-ray tube, an X-ray detector, and an image processing unit. Furthermore, the X-ray imaging device according to the invention comprises an interface via which the image processing unit can be connected to a catheter for acquiring an image data set for signal exchange. In this case, the image data set relates to the internal space of the blood vessel. Eventually, the image processing unit is configured to carry out the method according to the invention. In particular, there are two self-contained devices that are individually imaged, namely an X-ray device and an intravascular ultrasound device, which are combined with its interface and specially configured image processing unit to provide the present invention. X-ray imaging apparatus. By combining the individual image data of each partial system, a synergistic effect is obtained and a particularly meaningful composite image data set is provided.

  The preferred embodiments described with respect to the method according to the invention and their advantages apply correspondingly to the X-ray imaging device according to the invention.

  Hereinafter, the present invention will be described in more detail based on examples.

FIG. 1 shows a schematic view of a patient's heart examination according to an embodiment of the X-ray imaging apparatus according to the present invention. FIG. 2 shows a schematic diagram of the image processing steps in the method according to the invention.

  In FIG. 1 and FIG. 2, the same elements or functionally the same elements are denoted by the same reference numerals. The invention will be further described with reference to the drawings, in which embodiments of the invention are schematically shown.

  FIG. 1 shows an X-ray imaging apparatus 10 having an X-ray tube 12 and an X-ray detector 14. The X-ray tube 12 transmits X-rays toward the X-ray detector 14, and thus a two-dimensional image in the detection region E is acquired. These two-dimensional images are supplied to the computer 16. In this embodiment, the X-ray is used for examining the coronary blood vessel 26 of the heart 28 of the patient 30 lying in the detection region E. In the X-ray image 34, the contour and geometric shape of the coronary blood vessel 26 into which the contrast agent has been introduced can be well visualized. A biplane apparatus may be used instead of the illustrated monoprene X-ray imaging apparatus.

  In addition to the X-ray system, an IVUS device 20 for intravascular ultrasound is also provided, which IVUS device 20 includes a catheter 22 through which an ultrasound head 24 is introduced into a coronary vessel 26, It is moved within the coronary blood vessel 26. The ultrasonic head 24 includes an ultrasonic transmitter and an ultrasonic detector, and these acquire image data depicting the blood vessel inner wall of the coronary blood vessel 26. These image data are routed to the computer 16 via the interface 18 for further processing so that these image data can be displayed on the screen 32 along with the X-ray image 34 as an ultrasound image 36.

  The X-ray imaging apparatus 10 can also generate a composite X-ray image 34 rich in detail and contrast by sequentially capturing and superimposing a plurality of X-ray images one after another like a stroboscope. These multiple X-ray images must be acquired when the coronary blood vessels 26 in the detection region E are at the same geometric position. In order to ensure this, an ECG (electrocardiogram) device 42 for detecting the heartbeat of the heart 28 is provided. By always taking X-ray images in the same cardiac phase in this way, it is ensured that the movement of the coronary blood vessel 26 is removed as much as possible when the X-ray image 34 is created.

  FIG. 2 schematically shows how the position of the ultrasonic head 24 is measured and associated with the X-ray image 34 in the image processing method. In the first step, a series of X-ray images are taken under ECG synchronization by the X-ray imaging apparatus 10 as described above in a state where the coronary blood vessel 26 contains a contrast agent. The superposition of these individual X-ray images provides an X-ray image data set R1 in which the geometry and extension of the coronary vessel 26 is clearly visible based on the contrast agent. In this case, the ultrasonic head 24 has already been introduced into the body of the patient 30 but is not yet in the detection region E.

  In the second step, in the coronary vessel 26 that has finished administration of the contrast agent, the contrast agent is no longer present in the coronary vessel 26 due to the continuous blood flow through the coronary vessel 26. Again, a series of X-ray images are taken by the X-ray imaging apparatus 10 under ECG synchronization, and these X-ray images are superimposed to form one X-ray image data set R2. Because there is no contrast agent, the contour of the coronary blood vessel 26 hardly appears in the X-ray image data set R2, which is indicated by a broken line in FIG. In contrast, the cardiac pacemaker component 38 of the patient 30 and the surgical suture 40 appear clearly in the X-ray image data set R2. However, as an alternative, the ultrasonic head 24 may already exist in the detection region E when the X-ray image data set R2 is acquired (however, it is in a stationary state or a stationary state). Acquisition of the X-ray image data set R2 spans at least one respiratory cycle or heartbeat cycle.

  In the third step, the ultrasonic head 24 is placed at the starting position in the coronary blood vessel 26. While the ultrasonic head 24 is moved back from the starting position in the coronary blood vessel 26 through the catheter 22, fluoroscopy is performed by the X-ray imaging apparatus 10 (without the contrast medium again), that is, a series of X-ray image data. Sets R3a to R3d are acquired. In each of these X-ray image data sets R3a, R4b, R3c, R3d, the ultrasonic head 24 takes a different position in the coronary blood vessel 26. The cardiac pacemaker component 38 or suture 40 is stationary or fixed in position and thus appears at the same geometric position in the X-ray image data sets R3a-R3d.

  To avoid erroneously identifying the part 38 or stitching 40 as the ultrasound head 24 in the segmentation algorithm that proceeds in the computer 16, the fourth step is now an X-ray image (stored in the computer 16). By subtracting the data set R2 from each of the X-ray image data sets R3a to R3d, the attached difference image data sets Sa, Sb, Sc, Sd are generated. As schematically shown in FIG. 2, the data belonging to the part 38 or the stitching portion 40 is erased in these difference image data sets Sa to Sd, and only the ultrasonic head 24 now appears. In the segmentation method performed here, the ultrasonic head 24 can be clearly identified and the position thereof can be measured by the coordinates x ′ and y ′.

  Before performing subtraction (represented by a minus sign circled in FIG. 2), the X-ray image data sets R2, R3a-R3d are filtered by a low pass filter (eg, Gaussian filter), Thereby, it is desirable to minimize the adverse effects of noise. In order to guarantee reliable subtraction, the X-ray image data sets R2, R3a-R3d are acquired at the same cardiac time phase, which is guaranteed by the ECG device 42. In the segmentation method, a local maximum intensity value generally assigned to the ultrasonic head 24 can also be detected. For this purpose, a threshold criterion may be set.

  In this embodiment, the relationship between the coordinate system of the X-ray image data set R1 having the coordinates x and y and the coordinate system of the difference image data sets Sa to Sd having the coordinates x 'and y' is known. Therefore, the position of the ultrasonic head 24 in the coronary blood vessel 26 can be uniquely measured. In this manner, images Xa to Xd in which the ultrasonic head 24 in the coronary blood vessel 26 can be viewed can be provided. This additional image processing step is represented by a plus sign. These images Xa-Xd can now be displayed on the screen 32 instead of the X-ray image 34. In addition, according to the respective position of the ultrasound head 24 in the coronary vessel 26 now, a coronary vessel inner wall representation belonging to this position can be shown in the ultrasound image 36 on the right side of the screen 32. This display format is very intuitive and easily understood by the treating physician.

  In the past, the ECG device 42 utilized only the movement resulting from the pumping action of the heart. However, it is also possible to take advantage of coronary vessel motion due to respiration. For this purpose, for example, a second X-ray image data set R2 having 15 images per second and a relatively low X-ray dose per image is acquired. This series of images clearly reveals the movement caused by the overlapping of respiratory and heart movements. The heartbeat motion can be calculated from data acquired by the ECG device 42. As a result, respiratory motion can be estimated. By automatic comparison of individual images in the image series, an image center (COM = Center of Mass) having a motion that reproduces the respiratory motion can be obtained.

  Since the X-ray image data sets R3a to R3d are also acquired under the same conditions, the difference image data is determined each time by determining the cross-correlation between the X-ray image data set R2 and the X-ray image data sets R3a to R3d. The image data set pair that forms the basis for determining the set can be selected. In this way, the respiratory motion is erased in the difference image data sets Sa to Sd.

  Further, in order to minimize image noise in the difference image data sets Sa to Sd, still image information and possibly extra image information in the X-ray image data sets R2 and R3a to R3d may be used. In this case, for example, the paragraph “non-gated dual-energy radiography” co-authored by Yiannis Kyriakou et al. An image processing method known from the prior art as described in “Motion-free merging” can be applied.

DESCRIPTION OF SYMBOLS 10 X-ray imaging device 12 X-ray tube 14 X-ray detector 16 Computer 18 Interface 20 IVUS apparatus 22 Catheter 24 Ultrasonic head 26 Coronary blood vessel 28 Heart 30 Patient 32 Screen 34 X-ray image 36 Ultrasound image 38 Heart pacemaker 40 Suture part 42 ECG (electrocardiogram) apparatus E Detection area R1 X-ray image data set R2 X-ray image data sets R3a to R3d X-ray image data sets Sa to Sd Difference image data sets Xa to Xd Image x, y coordinates x ′, y ′ coordinates

Claims (11)

A method for measuring a position of a movable object (24) in a process in which a movable object (24) that absorbs X-rays more strongly than a living tissue moves in a blood vessel (26) of the living body (28, 30),
a) a first for at least one site of the living body (28, 30) comprising at least partially a blood vessel (26) containing a contrast agent at a first concentration before or after the movement of the movable object (24); Obtaining an X-ray image data set (R1);
b) before or after the movement of the movable object (24), the blood vessel (26) containing data relating to the part in a state of containing a contrast agent at a concentration lower than the first concentration or not at all; Two X-ray image data sets (R2) are acquired;
c) During the movement of the movable object (24), at least one third X-ray image containing data relating to the part, with the blood vessel (26) containing the contrast agent at the low concentration or not at all. Obtaining a data set (R3a, R3b, R3c, R3d);
d) The spatially assignable data values of the second X-ray image data set (R2) and the third X-ray image data set (R3a, R3b, R3c, R3d) are subtracted from each other to obtain the second A difference image data set (Sa, Sb, Sc, Sd) composed of the X-ray image data set (R2) and the third X-ray image data set (R3a, R3b, R3c, R3d);
e) performing a segmentation method on the difference image data set (Sa, Sb, Sc, Sd) to identify data that can be assigned to the movable object (24);
f) a step of assigning the data of the first X-ray image data set (R1) to the data of the difference image data set (Sa, Sb, Sc, Sd) by obtaining a geometric assignment rule that can be given in advance; ,
g) The position of the movable object (24) in the blood vessel (26) is measured based on the first X-ray image data set (R1) and the data identified and assignable to the movable object (24). And steps
A method for measuring the position of a movable object.   Step c) follows steps a) and b) in time, and in step c), a plurality of third X-ray image data sets (R3a, R3b, R3c, R3d) are acquired in succession. Method according to claim 1, characterized in that the position of the movable object (24) is measured according to steps d) to g) for each of the third X-ray image data sets (R3a, R3b, R3c, R3d). .   While acquiring at least one of the third X-ray image data sets (R3a, R3b, R3c, R3d), one other image data set (36) relating to the interior space of the blood vessel (26) is obtained from the blood vessel (26). Method according to claim 1 or 2, characterized in that it is obtained by a movable object (24) within.   The method according to claim 3, characterized in that another image data set (36) is assigned to the position of the movable object (24) whose position in the blood vessel (26) has been measured.   Method according to claim 3 or 4, characterized in that the movable object (24) comprises a catheter (24) and the other image data set (36) is obtained by intravascular ultrasound.   The blood vessel (26) moves substantially periodically, and at the same phase position of the periodic movement, the first X-ray image data set (R1) and the second X-ray image data set (R2), and / or One X-ray image data set (R1) and a third X-ray image data set (R3a, R3b, R3c, R3d) and / or a second X-ray image data set (R2) and a third X-ray image 6. The method according to claim 1, wherein a data set (R3a, R3b, R3c, R3d) is obtained.   Periodic motion is detected by a measurement unit (42), preferably an electrocardiogram detector (42), and the first X-ray image data set (R1) and / or the second X-ray image data set (R2) and / or The method according to claim 6, characterized in that the acquisition time point of the third X-ray image data set (R3a, R3b, R3c, R3d) is determined based on the data supplied from the measurement unit (42).   The blood vessel (26) moves in response to the overlap of the first and second periodic motions, the first periodic motion is detected by the measurement unit (42), and the second periodic motion is A plurality of first X-ray image data sets (R1) and / or second X-ray image data sets (R2) and / or third X-ray image data sets (R3a, R3b, R3c, R3d) Determining the spatial assignment of the data values in step d) and / or the geometric assignment rules that can be given in advance in step f) are detected first and second The method according to claim 6 or 7, characterized in that it is carried out depending on the spatial movement of   In step f), the allocation rule is determined by the first X-ray image data set (R1), the second X-ray image data set (R2) and / or the third X-ray image data set (R3a, R3b). , R3c, R3d) and / or the registration with the difference image data set (Sa, Sb, Sc, Sd).   The determination of the assignment rule in step f) includes the coordinate system (x, y) assigned to the first X-ray image data set (R1), the second X-ray image data set (R2) and / or Between the third X-ray image data set (R3a, R3b, R3c, R3d) and / or the coordinate system (x ′, y ′) assigned to the difference image data set (Sa, Sb, Sc, Sd) 10. The method according to claim 1, wherein the method is performed by a coordinate transformation.   In order to carry out the method according to one of claims 1 to 10, in an X-ray imaging device (10) comprising an X-ray tube (12), an X-ray detector (14) and an image processing unit (16). , An interface (18) through which the image processing unit (16) obtains an image data set relating to the internal space of the blood vessel (26) with respect to signal exchange (20, 22). An X-ray imaging apparatus that can be connected to the X-ray imaging apparatus.

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