DE102004011158B4 - Method for registering a sequence of 2D slice images of a cavity organ with a 2D X-ray image - Google Patents

Abstract

method for registering a sequence of 2D slice images (4) of a cavity organ (2) an examination area (3) under simultaneous fluoroscopy of the examination area (3) with an imaging, endoluminal Instrument (1) are detected, with at least one 2D X-ray (12) of the examination area (3), with the same geometric Imaging parameters recorded with which the fluoroscopy carried out in which fluoroscopy images (5) are taken from fluoroscopy and at least approximately the same time how the 2D slice images (4) were recorded by an image processing algorithm a respective position (9, 9a, 9b) of a tip of the instrument (1) determined and together with each to approximately the same Time recorded 2D slice image (4) in an image database (13) is stored, characterized in that during a movement of the hollow organ (2) between the recording of the 2D X-ray image (12) and the recording of the sequence of 2D slice images (4) and / or during the Recording the sequence of 2D slice images (4) an adjustment a course of the determined from the fluoroscopic images (5) positions ...

Description

method for registering a sequence of 2D slice images of a cavity organ with a 2D X-ray The present invention relates to a method for registration a sequence of 2D sectional images of a hollow organ of an examination area, in particular a vessel, the with simultaneous fluoroscopy of the examination area with an imaging, endoluminal instrument, with at least one 2D X-ray of the examination area, with the same geometric imaging parameters recorded with which the fluoroscopy is performed, when in fluoroscopy images obtained from fluoroscopy be and at least approximate same times as the 2D slice images were recorded, by an image processing algorithm a respective position a tip of the instrument and determined together with each to approximate same time recorded 2D slice image in an image database is stored.

With imaging, endoluminal instruments can be two-dimensional Images of the interior of a hollow channel, in particular a vessel or a Hollow organ, record. Here are imaging techniques like intravascular Ultrasound (IVUS), optical coherence tomography (OCT) or fluorescence imaging used. The picture recording takes place during continuous or stepwise controlled movement of the instrument in the hollow channel. So, can be, for example, with imaging intravascular Catheters two-dimensional sectional images from the inside of vessels, z. B. from the vascular system of the heart, deliver.

From the DE 199 19 907 A1 a method for catheter navigation in three-dimensional vascular tree recordings is known in which the spatial position of the catheter is detected and superimposed in a 3D view of a preoperatively recorded vascular tree. For this purpose, a catheter with an integrated position sensor is used, via which the respective current spatial position of the catheter tip is detected. Registration of this position sensor with the 3D image data takes place before the intervention via special markers, which are visible in the 3D image and approached with the catheter. Such registration is required for all applications in which the recorded 2D image data is to be combined with 3D image data.

The execution The recordings with the endoluminal instrument will usually performed under simultaneous fluoroscopy of the examination area, in which is the hollow channel to be examined. Look in real time The fluoroscopic images displayed by the examiner can be viewed at any time Position of the tip of his instrument in the examination area detect. The 2D slice images obtained with the imaging endoluminal instrument are stored in an image database to be examined Doctor available later do. Due to the usually very large number of image files, which are stored in such an investigation designed the follow-up examination of the image material, in the usual Directory structure of storage media is present, difficult and time consuming. It is indeed in support the localization of the recorded images possible while recording these images acoustic To record data, especially language, to later one to allow improved orientation in the footage however, this requires the reproduction of the appropriate material in order to the desired Find pictures.

For the user it is therefore desirable the corresponding image material based on a 2D x-ray image of the examination area the implementation Select the examination directly and to be able to view. However, this requires registration of the recorded 2D slice images with the illustrated 2D X-ray image to enable the positionally correct assignment of the 2D slice images.

The generic US 5,357,550 A describes a method for registering a sequence of 2D slice images of a cavity organ of an examination area, in which a periodic movement of the heart examined there using an ECG gating technique is taken into account by recording images only in a specific phase of the heartbeat. However, a compensation of the influence of movements of the patient itself can not be achieved.

In US 2002/0049375 A1 also discloses an ECG gating technique for reducing or avoiding the influence of a movement of an examined Cavity organ used. In the method described there are the endoluminal recorded 2D slice images respectively Fluoroscopy images associated simultaneously during the endoluminal Capture recorded.

issues However, arise during a movement of the cavity member between the recording of the (reference) 2D X-ray and the recording the sequence of 2D slices and / or while recording the Sequence of 2D slices. Such movements cause that the positions detected in the fluoroscopic images are the apex of the instrument does not coincide with the course of the cavity organ in the reference X-ray image.

The The object of the present invention is a method for registering a sequence of 2D slice images of a hollow channel, which are detected with an imaging, endoluminal instrument, with a 2D X-ray. of the investigation area, which is without significant Additional effort even with a movement of the cavity member between to realize the recordings.

The Task is solved by the method according to claim 1. advantageous Embodiments of the method are subject matter of the subclaims or can be the following description and the embodiments remove.

at the present method for registering a sequence of 2D slice images a hollow organ of an examination area, in particular of a vessel the 2D-section images under simultaneous fluoroscopy of the examination area with the imaging, captured endoluminal instrument. In the fluoroscopic images, the are obtained from fluoroscopy and at least approximately the same Times at which the 2D slice images were recorded is through an image processing algorithm of a respective position of Tip of the instrument and determined together with the respective nearly same time recorded 2D slice image in an image database saved.

According to the invention upon movement of the lumen member between the recording the 2D X-ray and recording the sequence of 2D slice images and / or during the Record the sequence of 2D slices an adaptation of a Course of the determined from the fluoroscopic images positions the tip of the instrument to the course of the cavity organ in the 2D X-ray.

such Movements can for example, by global patient movements, respiration or heartbeat arise. They lead to that the positions recognized in the fluoroscopic images the tip of the instrument not with the course of the cavity organ in the reference X-ray image. For this Customization offers different possibilities. So can eg. the curve resulting from the detected positions of the tip of the Instrumentes, by means of additional 2D / 2D registration (eg elastic registration) to those in the reference X-ray image shown course of the cavity organ to be adjusted. Farther can the individual fluoroscopy images first by means of 2D / 2D registration with the reference x-ray image for Cover be brought. The necessary transformations can then be used in the mapping between the positions of the top of the Instrument and the reference x-ray image be taken into account.

By this additional information to the respective 2D-sectional image, its Recording position within the fluoroscopic images, will register with a 2D X-ray of the examination area achieved with the same geometric imaging parameters with which fluoroscopy is also performed. The 2D-section images can do this from the user at any time the position within the 2D X-ray be found.

requirement for the execution On the one hand, the implementation of the Examination under fluoroscopy and on the other hand the record the 2D X-ray of the examination area, also referred to below as the reference X-ray image referred to, with the same geometric imaging parameters, d. H. Ray source-detector distance, Object-detector distance, etc., with which the fluoroscopy is performed, so that the reference X-ray picture and the fluoroscopy images show the same perspective as well have the same magnification. During execution of endovascular Examinations will preferably use this reference X-ray image clearly visible vessel filling recorded, d. H. eg with digital subtraction angiography. It can be but also one of the fluoroscopy images as a reference radiograph in which case, in comparison with the abovementioned angiography image not the vessels recognizable with the same good contrast.

The present method provides a simple way of registration the 2D slice images with a 2D X-ray of the examination area. In particular, there is no need for this registration special Position localization systems with the endoluminal instrument to link. It can be any radiopaque, Endoluminal imaging instrument can be used for the examination. The position determination takes place by means of an image processing algorithm, which requires only little effort. The fluoroscopy images are in such investigations usually due to the same time required fluoroscopy to control the instrument anyway available. Because the instrument is in close succession in time Fluoroscopy images can only be moved by small distances once in the fluoroscopy image by the image processing algorithm identified tip of the instrument quickly and robustly found become. This may reduce necessary inputs by the user and makes the procedure störunanfälliger.

By The registration with the reference X-ray image will be the user made possible by simple identification of a position in this X-ray image the 2D slice image from the image database recorded at this position to retrieve and represent. This finding of the 2D slice images on the the examiner well-known anatomy allows easy use of the procedure without any longer Training. The user has the opportunity by application his anatomical knowledge with a view from a large mass of image data to retrieve the relevant 2D image information. by virtue of The anatomical position irrelevant information can be fast be sorted out. By continuing in an embodiment of the given method present, markings in Reference X-ray image too can put on a later Time of the same or another user the relevant Sift positions quickly. This speeds up the follow-up and brings advantages in the workflow.

The Determination of the respective position of the tip of the instrument in the fluoroscopy images as well as the assignment of this position the respective 2D slice images can at different times respectively. According to one Embodiment of the In the present proceedings, this provision is made at any one time Time offline, d. H. after recording the 2D slice images. In this embodiment, it is necessary, along with the 2D slice images as well as the fluoroscopy images each to store a time information, the one later Assignment of the 2D slice images to the fluoroscopic images using at least approximately same recording time allows. This can, for example, by Storage of the absolute time of the recording of the respective Image, wherein the fluoroscopy system and the image acquisition system for the endoluminal 2D slice images each over have the exact same time have to. This can be over in the simplest case ensures two separate, high-precision clocks in both systems become. Of course it stands However, those skilled in the art will be free to use other techniques to ensure to insert the synchronous time information. The exchange of image data between the systems can later offline, eg over one suitable disk or a data line, at any time.

The second embodiment The present method does not require coupling of the image data with the help of the recording time. In this embodiment have to however, the image acquisition system for the endoluminal slice images as well as the fluoroscopy system during the image recording data coupled to a during the Image recording Exchange data between the two systems to be able to. The position of the tip of the instrument is during or immediately after taking a fluoroscopic image in real time from the image processing algorithm detected and transmitted to the image acquisition system for the 2D slice images. This position is then stored together with the endoluminal 2D slice image, that was recorded at that time.

In A development of the present method is a user interface to disposal provided that allows the user to in the on a display device illustrated reference X-ray image on desired Show bodies with a pointing device and thus the associated Get 2D slice image recorded at this position. The fetched 2D slice image is then preferably on the same display shown, on which also the one or more reference X-ray images be visualized.

The present method allows also the 2D / 2D registration of the 2D slice images with different ones Reference radiographs. In this case, either the examination must be repeated several times carried out or the fluoroscopy will be simultaneously different Perspectives performed, the reference radiographs correspond. In particular, two reference X-ray images are available, one of which is a lateral presentation and the other an anterior-posterior representation of the examination area supplies. The user interface allows in this case the selection from the different reference X-ray images, the course can also be displayed side by side at the same time on the display device.

The The present method will be described below with reference to exemplary embodiments explained in more detail in conjunction with the drawings. Hereby show:

1A D an example of the procedure of the registration according to a variant of the present method;

2 an example of the procedure of the registration according to another variant of the present method;

3 an example of an adaptation of the specific positions to the course of the vessel in the reference X-ray image;

4 an example of determining and interpolating positions using ECG gating;

5 an example for the visualization of the 2D slice images via a user interface; and

6 an example of a further embodiment of the user interface.

In the 1 and 2 2, the procedure of the 2D / 2D registration according to the present method will be explained in two variants using the example of an endovascular examination of a vascular system with a catheter as an endoluminal, imaging instrument. In both figures, the X-ray fluoroscopy images, ie the fluoroscopy images, are in each case in the upper part 5 , which are recorded during the investigation, in chronological order. These pictures show a vascular system 3 with one in one of the vessels 2 inserted catheter 1 , The catheter is removed from the vessel during the examination 2 pulled to different 2D slice images 4 in different places of the vessel 2 to obtain. These endovascular 2D slice images 4 are in the 1 and 2 each in the lower part in chronological order of recording shown.

In the first exemplary embodiment of the present method, each fluoroscopy image is taken while the examination is being performed 5 the shooting series associated with a time (t, t + 1, t + 2, ...) at which the fluoroscopic image was recorded. The time will be together with the respective fluoroscopic image 5 saved. This is done in the same way for recording the endovascular 2D slice images 4 , The image acquisition system for the endovascular 2D slice images is integrated with the X-ray system so that both systems have exactly the same time of day. This connection of the recorded images with the recording time is in the 1A illustrated. With the reference number 6 Here, for example, in the first image is the point of imaging through the endovascular catheter 1 indicated at the recorded at the same time t endovascular sectional image 4 which is indicated by the arrow. In the endovascular sectional images 4 are each the catheter axis 7 as well as the vessel wall 8th to recognize the vessel.

At any time after carrying out the examination, the fluoroscopy images 5 over the saved recording time the 2D-cut images recorded at the same recording time 4 assigned as in the 1B is illustrated. Subsequently, with an image analysis software, the catheter tip in the fluoroscopic images 5 identified. Suitable image processing algorithms for this purpose are known to the person skilled in the art. Due to the consecutive nature of the images, if the catheter or its tip has been detected once, possibly by user interaction, the catheter tip can be determined by such an image processing algorithm with high reliability. Suitable image analysis programs are known to the person skilled in the art.

Of course, the image analysis can also be done before assigning the fluoroscopy images 5 to the 2D-cut images 4 be performed. The determined position 9 the catheter tip is in the 1C illustrated in the upper part. In the fluoroscopy images shown 5 is this position 9 respectively highlighted by way of example.

With the aid of the time information stored for each image, each endovascular 2D slice image can be obtained 4 a geometric position in the fluoroscopic image 5 be assigned, as in the 1D is shown with the position information X and Y. As the reference X-ray image ideally with the fluoroscopic images 5 with regard to the geometric positions of the investigated vessel 2 exactly matches, is now to every 2D slice image 4 the corresponding recording position in the reference X-ray image known. This position in the reference X-ray image is stored in the image database for each endovascular 2D slice image. The data exchange, ie the transmission of images and positions, can be done by means of CD or data line to a workstation for further registration and storage. The storage of the positions to the 2D slice images is preferably carried out in the header of these 2D slice images.

Subsequently, the reference X-ray image can be displayed to a user on a screen, which can then call up and display the 2D slice image assigned to this position by simply indicating a position in the image representation. This is later in connection with the 5 and 6 again exemplified.

According to a second variant of the present method, as exemplified in connection with 2 is explained, the determination of the position of the catheter tip and the storage of this recording position with the endovascular 2D slice images 4 in real time while conducting the investigation. In this variant, a coupling with the help of the time is eliminated. However, the recording device for the endovascular slice images as well as the X-ray device for the fluoroscopy must be coupled in terms of data technology, because during the recording of images must be possible to exchange data between the two devices.

Immediately after recording each fluoroscopic image 5 and endovascular 2D slice image 4 In this variant, the determination of the position of the catheter tip in the fluorine microscopy image 5 through the image processing algorithm, as determined by the position 9 in the upper part of the 2 is indicated. The determined position 9 is immediately transmitted to the endovascular 2D slice acquisition device and along with the just-recorded endovascular 2D slice image 4 saved. This procedure is performed for each individual recorded image during the examination in real time. In this case, therefore, no further steps are required after carrying out the investigation, since the assignment between fluoroscopy image 5 and thus also the reference X-ray image and the endovascular 2D slice image due to the catheter position already stored with the latter.

Should not the reference X-ray image due to movements of the vessel between the taking of this reference X-ray image and the conduct of the examination with the fluoroscopic images 5 match exactly, so will an adaptation of the fluoroscopic images 5 determined positions 9 the catheter tip made with the vessel profile of the vessel 2 in the reference X-ray image. Thus, for example, there may be a shift in the respective images, as can be seen from the 3 which indicates the course of the vessel of the reference X-ray image and the catheter positions obtained from the examination 9 in the left part of the figure shifted from each other represents. Such displacement can be achieved by an adjustment of the catheter positions 9 determined course to the actual vessel course in the reference X-ray image, as illustrated in the right part of the figure. The catheter positions 9 are also corrected accordingly in the image database.

Another possibility is to perform ECG gating to correct movements associated with cardiac motion. Based on the ECG signal, the cardiac phase is known in each case, to which the reference X-ray image and the fluoroscopy images 5 were recorded. Upon registration, only the catheter tip positions will now be 9a used, which correspond to the heart phase of the reference X-ray image. The 4 shows in part figure A, the reference X-ray image of the vascular system, which was recorded in the cardiac phase A. In this picture are also the positions 9 entered the catheter tip, resulting from the fluoroscopic images 5 result. Due to the heart movement, the course of these determined positions is correct 9 does not exactly match the course of the vessel in the reference X-ray image. In the presently explained technique now only the positions 9a utilized, which belong to the heart phase A. The intermediate positions 9b from the fluoroscopic images recorded in other cardiac phases 5 determined are discarded ( 4B ). Subsequently, the now missing positions between the positions 9a interpolated, so by a combination of positions 9a in heart phase A and the interpolated positions 9c the actual vascular course of the reference X-ray image is reproduced ( 4C ). The intermediate positions 9b are also in the image database through the interpolated positions 9c replaced.

5 finally shows an example of the representation of the 2D slice images 4 via a user interface on a screen 10 , The user interface allows the user to use a pointing device 11 to a desired location of the vascular system in the illustrated reference X-ray image 12 to show and thus the associated, endovascular 2D slice image 4 then on the same screen 10 is pictured. The figure shows the reference X-ray image 12 , which was preferably recorded with a contrast agent filling of the vessels. Shows the user with the pointing device 11 to a specific position in this radiograph 12 , the X and Y positions of the drawing device are determined within the image and in the image database 13 the associated endovascular 2D slice image 4 visited, which correlates with this position. This 2D section image 4 will then be in a subsection of the screen 10 as shown by the 5 is apparent.

In a further development of this user interface, a marking function is also provided with which the user can mark certain points in the reference X-ray image 14 can provide. The same user or even another user can then look at this reference X-ray image 12 at a later date immediately the 2D slice images 4 retrieve the corresponding locations that have been previously marked.

Claims (10)

Method for registering a sequence of 2D slice images ( 4 ) of a hollow organ ( 2 ) of an examination area ( 3 ) under simultaneous fluoroscopy of the examination area ( 3 ) with an imaging endoluminal instrument ( 1 ), with at least one 2D X-ray image ( 12 ) of the examination area ( 3 ) recorded with the same geometric imaging parameters with which the fluoroscopy is performed, in which in fluoroscopic images ( 5 ), which are obtained from the fluoroscopy and at least approximately the same time as the 2D slice images ( 4 ) have been recorded by an image processing algorithm ( 9 . 9a . 9b ) a tip of the instrument ( 1 ) and together with the 2D cross-sectional image respectively recorded at approximately the same time ( 4 ) in an image database ( 13 ) chert, characterized in that during a movement of the hollow organ ( 2 ) between the recording of the 2D X-ray image ( 12 ) and recording the sequence of 2D slices ( 4 ) and / or while recording the sequence of 2D slices ( 4 ) an adaptation of a course of the fluoroscopic images ( 5 ) certain positions ( 9 . 9a . 9b ) of the tip of the instrument ( 1 ) to the course of the cavity organ ( 2 ) in the 2D X-ray image ( 12 ) he follows. Method according to claim 1, characterized in that the determination of the position ( 9 . 9a . 9b ) while recording the sequence of 2D slices ( 4 ) in real time, with a data connection for transmitting the position ( 9 . 9a . 9b between a device for carrying out the fluoroscopy and a device for detecting the endoluminal 2D sectional images ( 4 ) is held. Method according to claim 1, characterized in that during the recording of the sequence of 2D slice images ( 4 ) with the 2D-cut images ( 4 ) and with the fluoroscopy images ( 5 ) a time information is stored, the subsequent assignment of the 2D slice images ( 4 ) to the fluoroscopic images ( 5 ) on the basis of an approximately same recording time, and the determination of the position ( 9 . 9a . 9b ) and assignment to the 2D slice images ( 4 ) based on the time information after recording the sequence of 2D slice images ( 4 ) is carried out. Method according to one of claims 1 to 3, characterized in that the 2D X-ray image ( 12 ) is recorded by means of subtraction angiography. Method according to one of claims 1 to 3, characterized in that as 2D X-ray image ( 12 ) one of the fluoroscopy images ( 5 ) is used. Method according to one of claims 1 to 5, characterized in that the 2D X-ray image ( 12 ) on a display device ( 10 ) and when marking one or when pointing to one, place in the representation of the 2D X-ray image ( 12 ) by a user the position associated with that position ( 9 . 9a . 9b ) and that to this position ( 9 . 9a . 9b ) stored 2D cross-sectional image ( 4 ) from the image database ( 13 ) is retrieved and displayed. A method according to claim 6, characterized in that the from the image database ( 13 ) retrieved 2D slice image ( 4 ) in another display area of the display device ( 10 ) is displayed as the 2D X-ray image ( 12 ). A method according to claim 6 or 7, characterized in that in the representation of the 2D X-ray image ( 12 ) certain areas or areas can be marked by a user in such a way that the markings are displayed on a later display of the 2D X-ray image ( 12 ) are recognizable. Method according to one of claims 1 to 8, characterized in that a plurality of 2D X-ray images ( 12 ) are recorded and registered from different perspectives. Method according to one of claims 1 to 9, characterized in that the adaptation of the course of the fluoroscopic images ( 5 ) certain positions ( 9 . 9a . 9b ) to the course of the cavity organ ( 2 ) in the 2D X-ray image ( 12 ) is carried out via transformations which are determined by a single comparison of the fluoroscopy images ( 5 ) with the 2D X-ray image ( 12 ).