DE102013205537A1 - Angiographic examination method for determining dimension in vasculature as investigation object of patient, involves determining and transmitting first two-dimensional position in two-dimensional projection image to volume record - Google Patents

Abstract

The method involves generating a volume record of investigation objects and registering volume record to C-arm (2). The gradient of object is determined and two-dimensional projection image of object is generated. The fusion of two-dimensional projection image and registered volume record is performed to generate two-dimensional image overlay. First two-dimensional position in two-dimensional projection image is determined and transmitted to volume record to determine first three-dimensional position in volume record.

Description

The invention relates to an angiographic examination method for determining a dimension in a vascular system as examination object of a patient by means of an angiography system with an X-ray source, an X-ray image detector, which are attached to the ends of a C-arm, a patient table with a table top for supporting the patient, a system control unit , an image system and a monitor.

Such an angiography system for carrying out an angiographic examination procedure is known, for example, from US Pat US 7,500,784 B2 known, based on the 1 will be explained below.

The 1 shows an exemplified monoplanes X-ray system with one of a stand 1 in the form of a six-axis industrial or articulated robot held C-arm 2 at the ends of which is an X-ray source, for example an X-ray source 3 with X-ray tube and collimator, and an X-ray image detector 4 are mounted as an image recording unit.

By means of the example of the US 7,500,784 B2 Known articulated robot, which preferably has six axes of rotation and thus six degrees of freedom, the C-arm 2 be spatially adjusted, for example, by turning around a center of rotation between the X-ray source 3 and the X-ray image detector 4 is turned. The angiographic X-ray system according to the invention 1 to 4 is in particular about centers of rotation and axes of rotation in the C-arm plane of the X-ray image detector 4 rotatable, preferably around the center of the X-ray image detector 4 and around the center of the X-ray image detector 4 cutting axes of rotation.

The known articulated robot has a base frame which is fixedly mounted, for example, on a floor. It is rotatably mounted about a first axis of rotation a carousel. On the carousel is pivotally mounted about a second axis of rotation a rocker arm, on which is rotatably mounted about a third axis of rotation, a robot arm. At the end of the robot arm, a robot hand is rotatably mounted about a fourth axis of rotation. The robot hand has a fastener for the C-arm 2 which is pivotable about a fifth axis of rotation and about a perpendicular thereto extending sixth axis of rotation rotatable.

The realization of the X-ray diagnostic device is not dependent on the industrial robot. It can also find common C-arm devices use.

The X-ray image detector 4 may be a rectangular or square semiconductor flat detector, preferably made of amorphous silicon (a-Si). However, integrating and possibly counting CMOS detectors may also be used.

In the beam path of the X-ray source 3 is on a tabletop 5 a patient table a patient to be examined 6 as a research object. At the X-ray diagnostic facility is a system control unit 7 with an image system 8th connected to the image signals of the X-ray image detector 4 receives and processes (controls are not shown, for example). The X-ray images can then be displayed on a monitor 9 to be viewed as. The monitor lights 9 can by means of a ceiling-mounted, longitudinally movable, swiveling, rotating and height-adjustable carrier system 10 be held with boom and lowerable arm. In the system control unit 7 is still a device 11 provided whose function will be described below.

Instead of in 1 For example, illustrated X-ray system with the stand 1 in the form of the six-axis industrial or articulated robot can, as in 2 simplified, the angiographic X-ray system also a normal ceiling or floor mounted bracket for the C-arm 2 exhibit.

Instead of the example shown C-arm 2 For example, the angiographic x-ray system may also include separate ceiling and / or floor mount brackets for the x-ray source 3 and the X-ray image detector 4 have, for example, are electronically rigidly coupled.

The X-ray source 3 emits a beam emanating from a beam focus of its X-ray source 12 pointing to the x-ray image detector 4 meets. If 3-D data sets according to the so-called DynaCT method, a method for Rotationsangiographie, created, the rotatably mounted C-arm 2 with X-ray source 3 and X-ray image detector 4 turned so that, like the 2 schematically shows in plan view of the axis of rotation, the X-ray shown here pictorially by its beam focus 3 as well as the X-ray image detector 4 in the beam path of the X-ray source 3 located object to be examined 13 in an orbit 14 move. The orbit 14 can be fully or partially traversed to create a 3-D data set or volume data set.

The C-arm 2 with X-ray source 3 and X-ray image detector 4 moves according to the DynaCT method preferably by at least an angular range of 180 °, for example 180 ° plus fan angle, and takes in rapid succession projection images from different projections. The reconstruction can only take place from a subarea of this recorded data.

In the object to be examined 13 it may be, for example, an animal or human body but also a phantom body.

The X-ray source 3 and the X-ray image detector 4 each run around the object 13 around, that's the X-ray 3 and the X-ray image detector 4 on opposite sides of the object 13 are opposite.

In normal radiography or fluoroscopy by means of such an X-ray diagnostic device, the medical 2-D data of the X-ray image detector 4 in the picture system 8th if necessary cached and then on a display of the monitor lights 9 played.

Such angiography systems are used in the field of fluoroscopy-guided interventional repair of abdominal aortic aneurysms.

An abdominal aortic aneurysm (AAA) or abdominal aortic aneurysm is a vascular tear on the abdominal aorta, an extension of the abdominal aorta below the exit of the renal arteries in the anterior / posterior diameter greater than 30 mm. This is treated by inserting a stent-graft. Guidewires and catheters are inserted into the aorta via the two strips, via which one or more stent grafts, ie vessel plasties, are inserted (see 3 ), as for example in Cardiology today, January 2011, page 36 are shown.

Even with relatively simple stents, which include, for example, only the leg arteries next to the aorta, the final stent sometimes has to be composed of a "main stent" and "partial stents". Stents for the leg arteries, the iliac artery, the common iliac arteries, are usually "flanged" to an aortic stent as the main stent, as will be described below with reference to FIGS 3 is explained. For more complex, so-called fenestrated or bebranten stents still further partial stents are added. In trials are methods to support these procedures by the anatomically correct superimposition of, for example, pre-segmented CT data that show the physician as a permanent roadmap the aorta and outgoing vessels, as z. B. in the DE 10 2011 005 777 A1 is described.

Nevertheless, the problem is still determining the length and thus the dimension of the partial or Iliac stent to be flanged. This length can be determined only conditionally before the operation even with a pre-segmented and measured data set. Although it is the length of the individual vessels known as the length of the centerlines, but not the later position of the leg openings of the introduced aortic stent. Although this position can be estimated with a known length of the aortic stent, it is only known during the intervention when the stent has been introduced.

At present, a special angio-catheter with markings at a distance of 1 cm is placed over the wire for this measurement after insertion of the aortic stent and probing of the leg opening with a guide wire, as will be described below with reference to FIGS 9 is explained in more detail. By "counting" the markers between the Iliaca bifurcation, the bifurcation Iliaca interna / externa, and bifurcation of the introduced aortic stent, the bifurcation aortae, the length of the required iliac stent is determined.

The invention is based on the object of designing an angiographic examination method for determining a dimension in a vascular system as the examination object of a patient of the type mentioned at the outset such that a calculation of these dimensions or lengths can easily be carried out non-invasively, ie without the above-mentioned example To introduce angio catheters.

The object is achieved for an angiographic examination method of the type mentioned by the features specified in claim 1. Advantageous embodiments are specified in the dependent claims.

• S1) Erzeugung eines Volumendatensatzes des Untersuchungsobjekts,
• S2) Registrierung des Volumendatensatzes zum C-Bogen,
• S3) Bestimmung des Verlaufs des Untersuchungsobjekts im Volumendatensatz,
• S4) Erzeugung von wenigstens einem 2-D-Projektionsbild des Untersuchungsobjekts,
• S5) 2-D/3-D-Fusionierung des wenigstens einen 2-D-Projektionsbildes und des registrierten Volumendatensatzes zur Erzeugung eines 2-D-Überlagerungsbildes,
• S6) Bestimmung einer ersten 2-D-Position im wenigstens einen 2-D-Projektionsbild,
• S7) Übertragung der bestimmten ersten 2-D-Position aufgrund der Registrierung vom wenigstens einen 2-D-Projektionsbild zum Volumendatensatz mittels Rückprojektion zur Bestimmung einer entsprechenden ersten 3-D-Position im Volumendatensatz,
• S8) Berechnung einer 3-D-Abmessung (45) entlang einer den Verlauf des Untersuchungsobjekts (15, 17) kennzeichnenden Linie zwischen der ersten 3-D-Position (43) und einer zweiten 3-D-Position (44) und
• S9) Ausgabe der 3-D-Abmessung.

The object is achieved for an angiographic examination method for determining a dimension in a vascular system according to the invention by the following steps:

• S1) generating a volume data set of the examination object,
• S2) registration of the volume data set to the C-arm,
• S3) determination of the course of the examination subject in the volume data record,
• S4) generating at least one 2-D projection image of the examination subject,
• S5) 2-D / 3-D fusing of the at least one 2-D projection image and the registered volume data set to produce a 2-D overlay image,
• S6) determining a first 2-D position in the at least one 2-D projection image,
• S7) transmitting the determined first 2-D position by registering from the at least one 2-D projection image to the volume data set by backprojecting to determine a corresponding first 3-D position in the volume data set,
• S8) calculation of a 3-D dimension ( 45 ) along a course of the examination subject ( 15 . 17 ) characterizing line between the first 3-D position ( 43 ) and a second 3-D position ( 44 ) and
• S9) Output of the 3-D dimension.

This allows a (semi-) automatic calculation of a dimension or length in a vascular system without having to insert an angiothoretic catheter.

• S1') Erzeugung eines Volumendatensatzes der wenigstens zwei Gefäße,
• S2') Registrierung des Volumendatensatzes zum C-Bogen,
• S3') Bestimmung des Verlaufs der wenigstens zwei Gefäße im Volumendatensatz,
• S4') Erzeugung von wenigstens einem 2-D-Projektionsbild der wenigstens zwei Gefäße mit dem eingebrachten Hauptstent,
• S5') 2-D/3-D-Fusionierung des wenigstens einen 2-D-Projektionsbildes und des registrierten Volumendatensatzes zur Erzeugung des 2-D-Überlagerungsbildes, in dem der eingebrachte Hauptstent und der vorsegmentierte Volumendatensatz anatomisch korrekt überlagert sind,
• S6') Bestimmung einer Position einer ersten Bifurkation, beispielsweise des Hauptstents, als erste 2-D-Position im wenigstens einen 2-D-Projektionsbild,
• S7') Übertragung der bestimmten 2-D-Position aufgrund der Registrierung gemäß Verfahrensschritt S2') vom wenigstens einen 2-D-Projektionsbild zum Volumendatensatz mittels Rückprojektion zur Bestimmung der 3-D-Position dieser ersten Bifurkation im Volumendatensatz,
• S8') Berechnung der 3-D-Länge des Gefäßes als 3-D-Abmessung zwischen der 3-D-Position der ersten Bifurkation und der Endposition des einzusetzenden Teilstents als zweite 3-D-Position und
• S9') Ausgabe der 3-D-Abmessung als Länge des zu wählenden und/oder einzusetzenden Teilstents.

The object is for an angiographic examination method for determining a dimension in a vascular system, in which the vascular system has at least two vessels as the examination object and to determine the dimension of a partial stent to be flanged to a main stent introduced in the region of a bifurcation of the two vessels during an observation by means of the angiography system is, according to the invention also solved by the following modified or adapted or extended steps:

• S1 ') generating a volume data set of the at least two vessels,
• S2 ') registration of the volume data set to the C-arm,
• S3 ') determining the course of the at least two vessels in the volume data set,
• S4 ') generating at least one 2-D projection image of the at least two vessels with the introduced main stent,
• S5 ') 2-D / 3-D fusing of the at least one 2-D projection image and the registered volume data set to produce the 2-D overlay image in which the introduced major stent and the pre-segmented volume data set are anatomically correctly superimposed,
• S6 ') determining a position of a first bifurcation, for example of the main stent, as a first 2-D position in the at least one 2-D projection image,
• S7 ') transmission of the determined 2-D position on the basis of the registration according to method step S2') from the at least one 2-D projection image to the volume data record by means of backprojection for determining the 3-D position of this first bifurcation in the volume data record,
• S8 ') calculation of the 3-D length of the vessel as a 3-D dimension between the 3-D position of the first bifurcation and the end position of the inserted partial stent as the second 3-D position and
• S9 ') Output of the 3-D dimension as the length of the partial stent to be selected and / or inserted.

It has proved to be advantageous if the volume data set of the at least two vessels according to the first method step before setting a main stent and that the at least one 2-D projection image are generated according to the fourth method step after setting the main stent.

According to the invention, the line characterizing the course of the examination object can be the centerline, which can be determined by segmentation of the examination subject.

Advantageously, the first 2-D position in the 2-D projection image may be the position of the bifurcation of the main stent and / or the second 3-D position may be a bifurcation Iliaca internals and externals.

According to the sixth method step, according to the invention, the determination of the first 2-D position in the 2-D projection image can be carried out automatically by a pattern recognition method in the fluoroscopic image.

Automatic detection of the main stent in the 2-D projection image is simplified when a mark is applied to the main stent.

A simple location of the main stent in the volume data set can be achieved if a position sensor is attached to the main stent.

According to the invention, the marker or the position sensor may be attached to the bifurcation of the main stent.

It has proven to be advantageous if the transmission of the determined 2-D position according to method step S7 ') due to the registration of at least one 2-D projection image to the volume data set by a backprojection to determine the 3-D position of this bifurcation of the main stent in the 3-D volume data record.

According to the invention, the backprojection of the determined 2-D position in the 2-D projection image into the volume data set can take place on the next point of the registered centerline of the aorta and / or the vessel level determined by the registered centerline of the aorta.

A more accurate reconstruction or localization is possible when back-projection of the particular 2-D position from multiple 2-D projection images from different angulations.

Advantageously, to calculate the 3-D dimension according to the eighth method step, the distance between the first 3-D position and the user pre-operatively z. B. landmarks set in the Iliacalgefäßen be calculated as a second 3-D positions.

It has proved to be advantageous if, for the calculation of a 3-D dimension according to the eighth method step, the distance between the first 3-D position and positions of intra-operatively introduced and z. B. automatically detected instruments (guide wires, catheters, etc.) is determined.

According to the invention, the volume data set can be a registered pre-operative MR angiography or computed tomography.

Appropriately, a segmentation of the examination object in the reference image can take place.

Advantageously, the vessel in the area of the bifurcation can be an aorta with the arteries Iliaca communis sinistra or dextra as bifurcation or an artery Iliaca communis sinistra or dextra with the arteries Iliaca externa and interna as bifurcation.

According to the invention, the main stent may be an aortic stent and the partial stent may be an iliac stent to be flipped.

Conveniently, the 2-D projection images may be fluoroscopic live images, fluoroscopic images or DSA images.

The invention is explained in more detail with reference to embodiments shown in the drawing. Show it:

1 a known C-arm angiography system with an industrial robot as a carrying device,

2 a schematic representation of the geometric relationships in rotational angiography with the C-arm angiography according to 1 .

3 an abdominal aorta with an aortic aneurysm,

4 the aorta according to 3 with inserted stent-graft,

5 a pre-segmented volume data set of aortic CT angiography,

6 a representation for explaining the principle of a 2-D / 3-D overlay,

7 a representation to explain the principle of a 2-D / 2-D overlay,

8th a schematic representation for determining the dimension of the iliac stent,

9 a fluoroscopic image with an angiographic catheter with marks for intra-operative length measurement according to the prior art,

10 a pre-segmented 2-D / 2-D overlay image with centerlines for the determination according to the invention of the position of the bifurcation of the aortic stent,

11 a pre-segmented volume data set for the length measurement according to the invention of the inserted iliac stent,

12 a process according to the invention for measuring the length of the Iliacal stent to be used based on 2-D and 3-D images and

13 a flowchart of the procedure according to 11 ,

In the 3 is an abdominal aorta 15 presented having an abdominal aortic aneurysm (AAA) 16 having. An abdominal aortic aneurysm (AAA) 16 is a vessel eruption on the abdominal aorta 15 ,

The aortic aneurysm is treated 16 by inserting a stent-graft, ie a vascular plastic, as in 3 is shown. These are done via the two ledges through the leg arteries 17 guidewires 18 and catheters 19 into the aorta 15 introduced over which the stent-grafts 20 be introduced, as is the 4 shows.

For complex stent-grafts 20 that the leg arteries 17 sometimes the final stent must be composed of "partial stents", for example on an aortic stent 21 as the main stent, passing through the AAA into one of the leg arteries 17 , the iliac artery communis dextra, projects through a so-called window an iliac stent 22 as a partial stent for the other leg artery 17 , the iliac artery communis sinistra, is "flanged".

Based on 5 to 7 Now the principle of the 2-D / 2-D as well as the 2-D / 3-D-overlay will be explained in more detail.

To give the doctor even today additional information to assist in the setting of AAA stents, one is by means of a C- Arm system 2 to 4 created current fluoroscopy image a previously recorded reference image anatomically correct superimposed. This reference image can be a 3-D data set or volume data set 23 For example, a pre-segmented pre-operative computed tomography of an aorta 15 with an aortic aneurysm 16 , according to 4 be.

In the pre-interventionally generated volume data set 23 of the 5 is a 3-D segmentation 24 the aorta 15 with the abdominal aortic aneurysm 16 calculated from the then the centerline 25 the aorta 15 and the leg arteries 17 has been determined, which is still needed below.

The 6 now illustrates the superposition of a current fluoroscopic image with the volume data set 23 for example, as a 3-D grid model 26 may be present, as exemplified in the cube. The 3-D grid model 26 gets through a 3-D projection 27 into the fluoroscopic image as 2-D segmentation 28 pictured as indicated by the dotted lines 29 is symbolized, and you get a 2-D / 3-D overlay image 30 as a reference picture.

In the 7 however, there is no 3-D grid model 26 before, but only a 2-D projection image 31 for example, angiography. The abdominal aortic aneurysm 16 in the 2-D projection image 31 is segmented and this 2-D segmentation 32 through a 2-D projection 33 projected into the current fluoroscopic image (even if only from this exact view) and you get a 2-D / 2-D overlay image 34 as a reference picture.

For this 2-D overlay using, for example, a digital subtraction angiography (DSA) is indeed a unique contrast agent necessary, the advantage of the "normal" Roadmap, however, is that certain changes in the C-arm system 2 to 4 such as zoom, source image distance (SID) and / or small movements of the patient table with the tabletop 5 can be followed.

Is shown in the cases of the two 6 and 7 only the outline of the 2-D projection, not the full model.

• – Segmentierung der Aorta 15 mit dem abdominalen Aortenaneurysma 16 in dem 2-D-Projektionsbild 31 und
• – Einblenden der Umrisse der segmentierten Aorta als 2-D-Segmentierung 32 in das native Durchleuchtungsbild des 2-D-Projektionsbildes 31, der Angiographie.

From the 2-D projection image 31 to the 2-D / 2-D overlay image 34 Do you come with the following process steps:

• - Segmentation of the aorta 15 with the abdominal aortic aneurysm 16 in the 2-D projection image 31 and
• - Show the outlines of the segmented aorta as 2-D segmentation 32 into the native fluoroscopic image of the 2-D projection image 31 , the angiography.

• – ein zum C-Bogen 2 registrierter 3-D-Datensatz bzw. Volumendatensatz 23 sein, beispielsweise eine vorher durchgeführte CT-Angiographie oder eine während der Intervention aufgenommene Rotationsangiographie mit dem C-Bogen 2, oder
• – ein zum C-Bogen 2 registriertes 2-D-Projektionsbild 31 (beispielsweise eine DSA), die sich z. B. den verschiedenen Zoom-, SID-, Tischeinstellungen etc. anpasst. (siehe DE 10 2008 023 918 A1 ) SID = Source Image Distance / = Abstand Röntgenstrahler/Röntgendetektor

The basic requirement for the representation according to the invention is a C-arm 2 Registered adaptive reference image, as the basis of the 10 and 11 will be explained further. This can either

• - one to the C-arm 2 Registered 3-D data set or volume data record 23 For example, a previously performed CT angiography or recorded during the intervention rotational angiography with the C-arm 2 , or
• - one to the C-arm 2 registered 2-D projection image 31 (For example, a DSA), the z. B. the various zoom, SID, table settings, etc. adapts. (please refer DE 10 2008 023 918 A1 ) SID = Source Image Distance / = distance X-ray source / X-ray detector

In the 8th becomes the "flanging" of an iliac stent 22 to the aortic stent 21 illustrated. After the main or aortic stent 21 into the aorta 15 is inserted through an opening in the main or aortic stent 21 the guidewire 18 introduced. Over this is then the Iliacalstent 22 , a partial stent for the leg artery 17 , introduced and anchored.

The pre-operative determination of the dimension 36 or length of the Iliac stent 22 is not exactly possible in this case, since the bifurcation 35 of the aortic stent 21 ultimately only known when the aortic stent 21 was discontinued during the intervention.

For intra-operative length measurement of, for example, partial stents has been a special angio catheter 37 with markings 38 placed in the 1cm distance, as in the fluoroscopic image 39 of the 9 can be seen. Based on the "counting" of these marks 38 between in the fluoroscopic image 39 recognizable Iliaca bifurcation and the bifurcation 35 of the inserted aortic stent 21 then becomes the dimension 36 or length of the required Iliac stent 22 certainly

• a) Im durch 2-D/3-D-Fusionierung von Durchleuchtungsbild und zum C-Bogen 2 registrierter prä-operativer CT-Aufnahme erzeugten 2-D/3-D-Überlagerungsbild 30 sind nun der eingebrachte Aortenstent 21 und der vorsegmentierte Volumendatensatz 23 anatomisch korrekt überlagert und im vorsegmentierten Durchleuchtungsbild 40 wiedergegeben. In diesem wird die 2-D-Position 41 der Bifurkation 35 des Aortenstents 21 beispielsweise manuell durch "Klicken" auf die entsprechende Stelle im vorsegmentierten Durchleuchtungsbild 40 markiert.
• b) Aufgrund der Registrierung zwischen vorsegmentiertem Durchleuchtungsbild 40 und der CT-Information des Volumendatensatzes 23 zum C-Bogen 2 ist nun auch (z. B. durch eine Rückprojektion 42 der 2-D-Position 41 auf die Centerline 25) die 3-D-Position 43 dieser Bifurkation 35 des Aortenstents 21 im Volumendatensatz 23 bekannt.
• c) Nun kann die 3-D-Abmessung 45, also die echte Gefäßlänge, gegeben durch die Centerline 25 zwischen der 3-D-Position 43 der Bifurkation 35 des Aortenstents 21 und beispielsweise der 3-D-Position 44 der Bifurkation Iliaca Interna und Externa, die über die Segmentierung bekannt ist, berechnet werden. Diese 3-D-Abmessung 45 entspricht der Länge der zu wählenden Iliacalstents.

Based on 10 and 11 Now the principle of the inventive, intra-operative, non-invasive length measurement will be described in more detail.

• a) In by 2-D / 3-D fusion of fluoroscopic image and to the C-arm 2 registered pre-operative CT scan generated 2-D / 3-D overlay image 30 are now the introduced aortic stent 21 and the pre-segmented volume data set 23 anatomically correctly superimposed and in the pre-segmented fluoroscopic image 40 played. This will be the 2-D position 41 the bifurcation 35 of the aortic stent 21 For example, manually by clicking on the corresponding location in the pre-segmented fluoroscopic image 40 marked.
• b) Due to the registration between pre-segmented fluoroscopic image 40 and the CT information of the volume data set 23 to the C-arm 2 is now too (eg by a back projection 42 the 2-D position 41 on the centerline 25 ) the 3-D position 43 this bifurcation 35 of the aortic stent 21 in the volume data set 23 known.
• c) Now the 3-D dimension 45 So the real vessel length, given by the centerline 25 between the 3-D position 43 the bifurcation 35 of the aortic stent 21 and, for example, the 3-D position 44 of the bifurcation Iliaca Interna and Externa, which is known about segmentation. This 3-D dimension 45 corresponds to the length of the Iliac stent to be selected.

Should the 3-D position 44 For example, if the bifurcation Iliaca Interna / Externa can not be determined from the segmentation, it can be like the 3-D position 43 the bifurcation 35 of the aortic stent 21 via a correspondingly marked 2-D position in the fluoroscopic image 40 and the rear projection 42 on the centerline 25 in the pre-segmented volume dataset 23 be determined.

In the 12 is an inventive procedure for calculating the 3-D dimension 45 or length based on 2-D and 3-D images.

In a first method step S1) becomes a volume data set 23 of the examination object 15 respectively. 17 generated ( 46 ).

This volume data set 23 becomes the C-arm in a second method step S2) 2 registered ( 47 ).

Then in a third method step S3) a determination 48 the course of the examination subject 15 . 17 in the volume data set 23 carried out, in particular the centerline 25 is determined.

According to a fourth method step S4), at least one 2-D projection image is formed 31 of the examination object 15 to 17 generated ( 49 ).

This at least a 2-D projection image 31 in a fifth process step S5) in a 2-D / 3-D-fusion ( 50 ) with the registered volume data set 23 for generating a 2-D overlay image 30 . 34 combined.

In a sixth method step S6), a determination ( 51 ) of a first 2-D position 41 in at least one 2-D projection image 31 ,

Thereafter, in a seventh method step S7), the determined first 2-D position 41 due to the registration of the at least one 2-D projection image 31 to the volume data set 23 by means of rear projection ( 52 ) for determining a corresponding first 3-D position 43 in the volume data set 23 transfer.

Subsequently, in an eighth method step S8), a calculation ( 53 ) of a 3-D dimension 45 along a course of the examination subject 15 to 17 characterizing line 25 between the first 3-D position 43 and a second 3-D position 44 carried out.

In the ninth and last step S9) an output ( 54 ) of the calculated in the eighth step S8) 3-D dimension 45 For example, the examining physician can then provide the required iliac stent 22 can choose.

The 13 shows a flowchart of the procedure according to 12 , Starting from a pre-operatively created volume dataset 46 will be a 3-D registration 47 of the volume data set 46 to the C-arm 2 carried out. After a segmentation of the volume data set 46 From this a determination is made 48 the centerline 25 ,

During an intervention, projection images become 49 which may be fluoroscopic live images, fluoroscopic images or DSA images. The volume data set 46 and these projection pictures 49 be by means of a 2-D / 3-D-fusion 50 superimposed anatomically correct. In a projection picture 49 a position determination takes place 51 for example, the bifurcation 35 of the aortic stent 21 , Due to a rear projection 52 becomes this bifurcation 35 in the volume data set 46 determined. Starting from this bifurcation 35 in the volume data set 46 becomes a calculation 53 the 3-D dimension 45 performed and the numerical value as output 54 the 3-D dimension and thus, for example, the length of the Iliac stent to be selected and used 22 displayed.

In the present patent application, to measure the required length of a bifurcation to be used 35 of the aortic stent 21 to be flipped Iliacalstents 22 a combination of information from a pre-operative possibly pre-segmented computed tomography and an intra-operative fluoroscopic image described.

Prerequisite for this solution according to the invention are a volume data set 23 the aorta 15 and the leg arteries 17 , the iliac vessels, as well as the information about their course in this volume data set 23 , for example through their centerline 25

• – eine prä-operative, zum C-Bogen 2 registrierte CT- oder MR-Angiographie oder
• – eine intra-operative Rotationsangiographie zur Weichteildarstellung mit einem C-Bogen-System 2 bis 4, eine sogenannte DynaCT^®, wie sie in der US 7,734,009 B2 beispielsweise beschrieben ist,

sein. Die Centerline 25 erhält man bekannterweise über eine Segmentierung 28 des Volumendatensatzes 23. The volume data set 23 can, for example

• - a pre-operative, to the C-arm 2 registered CT or MR angiography or
• - An intra-operative rotation angiography for soft tissue imaging with a C-arm system 2 to 4 , a so-called DynaCT ^® , as used in the US 7,734,009 B2 For example,

be. The centerline 25 it is known to obtain via a segmentation 28 of the volume data set 23 ,

Furthermore, the volume data set should be 23 to the C-arm 2 be registered (eg via a 3-D / 3-D registration) 47 with a C-arm CT or a 2-D / 3-D registration). It is irrelevant whether this registration is rigid or non-rigid.

• 1. Zunächst wird vom Arzt (auf welche Weise auch immer) der Haupt- oder Aortenstent 23 in die Aorta 15 eingebracht und freigesetzt. Dies geschieht unabhängig von dem erfindungsgemäßen Verfahren, das erst danach einsetzt. Der Eingriff kann beispielsweise durch die Arteria iliaca communis mittels minimal-invasiver Chirurgie oder der sogenannten Schlüssellochchirurgie unter Durchleuchtung erfolgen.
• 2. Im 2-D/3-D-Überlagerungsbild (2-D/3-D-Fusionierung von Durchleuchtungsbild 37 und registrierter prä-operativer Computertomographie des Volumendatensatzes 23) sind nun die Abbildung des eingebrachten Aortenstents 21 und der vorsegmentierte Volumendatensatz 23 anatomisch korrekt überlagert.
• 3. Anschließend wird im 2-D-Projektionsbild 31 die Position 41 der Bifurkation 35 des Aortenstents 21, im Weiteren Stent-Bifurkation 35 genannt, markiert (beispielsweise manuell durch "Klicken" mit einer Computermaus auf die entsprechende Position im Durchleuchtungsbild 40).
• 4. Aufgrund der Registrierung zwischen 2-D-Projektionsbild 31 bzw. Durchleuchtungsbild 40 und CT-Information des Volumendatensatzes 23 ist nun auch (z. B. durch Rückprojektion 42 auf die Centerline 25) die 3-D-Position 44 dieser Stent-Bifurkation 35 im Volumendatensatz 23 bekannt.
• 5. Nun kann die 3-D-Abmessung 45, also die echte Gefäßlänge, die sich durch die Centerline 25 ergibt, zwischen der ersten 3-D-Position 43 der Stent-Bifurkation 35 und der zweiten 3-D-Position 44 z. B. der über die Segmentierung bekannte Bifurkation Iliaca Interna und Externa berechnet werden. Diese 3-D-Abmessung 45 auf der Centerline 25 zwischen den beiden Positionen 43 und 44 entspricht der tatsächlichen Länge der zu wählenden Iliacalstents.

The following describes a possible workflow for determining the lengths of the iliac stents.

• 1. First, the doctor (in whatever way) the main or aortic stent 23 into the aorta 15 introduced and released. This happens independently of the method according to the invention, which only starts afterwards. For example, the intervention can be performed by the common iliac artery using minimally invasive surgery or the so-called keyhole surgery under fluoroscopy.
• 2. In the 2-D / 3-D overlay image (2-D / 3-D fusion of fluoroscopic image 37 and registered pre-operative computed tomography of the volume data set 23 ) are now the image of the introduced aortic stent 21 and the pre-segmented volume data set 23 superimposed anatomically correct.
• 3. Subsequently, in the 2-D projection image 31 the position 41 the bifurcation 35 of the aortic stent 21 , in addition stent bifurcation 35 called (for example, manually by clicking with a computer mouse on the appropriate position in the fluoroscopic image 40 ).
• 4. Due to the registration between 2-D projection image 31 or fluoroscopic image 40 and CT information of the volume data set 23 is now too (eg by backprojection 42 on the centerline 25 ) the 3-D position 44 this stent bifurcation 35 in the volume data set 23 known.
• 5. Now the 3-D dimension 45 So the real vessel length that extends through the centerline 25 results between the first 3-D position 43 the stent bifurcation 35 and the second 3-D position 44 z. B. the known about the segmentation bifurcation Iliaca Interna and Externa be calculated. This 3-D dimension 45 on the centerline 25 between the two positions 43 and 44 corresponds to the actual length of the Iliac stents to be selected.

In the following, further embodiments or variations of the workflow described above are described.

• • die Stent-Bifurkation 35 durch ein Mustererkennungs-Verfahren im Durchleuchtungsbild automatisch erkannt werden,
• • am Aortenstent 21 an der Bifurkation 35 eine spezielle Markierung angebracht sein, die eine automatische Erkennung im 2-D-Projektionsbild 31 vereinfacht,
• • am Aortenstent 21 (z. B. an der Bifurkation 35) auch ein Positionssensor angebracht sein, der eine Lokalisierung der Bifurkation 35 im 3-D-Volumendatensatz 23 erlaubt, und
• • statt der Stent-Bifurkation 35 selbst ein beliebiger anderer Punkt markiert oder erkannt wird, der zur Berechnung von Längen oder Abmessungen dienen kann.

This described procedure can have the following variations:
In the step of determining or marking the 2-D position 41 the stent bifurcation 35 , can

• • the stent bifurcation 35 be detected automatically by a pattern recognition method in the fluoroscopic image,
• • at the aortic stent 21 at the bifurcation 35 a special mark may be attached, which provides automatic recognition in the 2-D projection image 31 simplified,
• • at the aortic stent 21 (eg at the bifurcation 35 ) may also be attached a position sensor that localizes the bifurcation 35 in the 3-D volume data set 23 allowed, and
• • instead of the stent bifurcation 35 even any other point is marked or recognized, which can be used to calculate lengths or dimensions.

• • Die Rückprojektion 42 der oben erkannten 2-D-Position 41 der Stent-Bifurkation 35 kann aus einer Projektion in den Volumendatensatz 23 durch Projektion der 2-D-Position 41 auf den nächsten Punkt der registrierten Aorten-Centerline oder Projektion der 2-D-Position 41 auf den nächsten Punkt der durch die registrierte Aorten-Centerline bestimmten Gefäßebene erfolgen.
• • Die Rückprojektion 42 der oben erkannten 2-D-Position 41 der Stent-Bifurkation 35 kann aus 2-D-Aufnahmen aus mehreren Angulationen erfolgen, wobei eine Rekonstruktion von der 3-D-Position 43 aus den 2-D-Positionen 41 und Rückprojektion 42 in den registrierten Volumendatensatz 23, eine Rekonstruktion von der 3-D-Position 43 aus den 2-D-Positionen 41 und Projektion auf den nächsten Punkt der registrierten Aorten-Centerline oder eine Rekonstruktion von der 3-D-Position 43 aus den 2-D-Positionen 41 und Projektion auf den nächsten Punkt der durch die registrierte Aorten-Centerline bestimmten Gefäßebene, sodass eine genauere Rekonstruktion oder Lokalisierung möglich ist.

The process step of rear projection 42 the stent bifurcation 35 , may have the following variations:

• • The rear projection 42 the above-recognized 2-D position 41 the stent bifurcation 35 may be from a projection in the volume data set 23 by projection of the 2-D position 41 to the next point of the registered aortic centerline or projection of the 2-D position 41 to the next point of the vessel level determined by the registered aortic centerline.
• • The rear projection 42 the above-recognized 2-D position 41 the stent bifurcation 35 can be made from 2-D images from multiple angulations, with a reconstruction of the 3-D position 43 from the 2-D positions 41 and rear projection 42 in the registered volume data set 23 , a reconstruction of the 3-D position 43 from the 2-D positions 41 and projection to the nearest point of the registered aortic centerline or reconstruction from the 3-D position 43 from the 2-D positions 41 and projecting to the next point of the vessel plane determined by the registered aortic centerline so that a more accurate reconstruction or localization is possible.

• • der Abstand zwischen der 3-D-Position 43 und vom Benutzer gesetzten prä-operativen Landmarken (z. B. in den Iliacalgefäßen) oder
• • der Abstand zwischen der 3-D-Position 43 und intraoperativ eingebrachten (und z. B. automatisch erkannten) Instrumenten (Führungsdrähte, Katheter etc.) berechnet werden.

In the process step of the length calculation 53 can

• • the distance between the 3-D position 43 and user pre-operative landmarks (eg in iliac vessels) or
• • the distance between the 3-D position 43 and intraoperatively introduced (and, for example, automatically detected) instruments (guidewires, catheters, etc.).

The described workflow is not based on the calculation of the length of Iliacalstents 22 but may be applied as appropriate to the calculation of the length of fenestrations (eg, stents for renal arteries) or intracranial stents.

The advantage of this method according to the invention is the replacement of the intra-operative and invasive measurement of vessel lengths by a fast, safe and non-invasive method which makes use of already available images.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 7500784 B2 [0002, 0004]
• DE 102011005777 A1 [0018]
• DE 102008023918 A1 [0068]
• US 7734009 B2 [0088]

Cited non-patent literature

• Cardiology today, January 2011, page 36 [0017]

Claims (20)

Angiographic examination method for determining a dimension in a vascular system as an examination subject ( 15 . 17 ) of a patient ( 6 ) by means of an angiography system with an X-ray source ( 3 ), an X-ray image detector ( 4 ) at the ends of a C-arm ( 2 ), a patient table with a table top ( 5 ) for storage of the patient ( 6 ), a system control unit ( 7 ), an image system ( 8th ) and a monitor ( 9 ), characterized by the following steps: S1) generation ( 46 ) of a volume data set ( 23 ) of the examination subject ( 15 . 17 ), S2) Registration ( 47 ) of the volume data set ( 23 ) to the C-arm ( 2 ), S3) Determination ( 48 ) of the course of the examination subject ( 15 . 17 ) in the volume data set ( 23 ), S4) generation ( 49 ) of at least one 2-D projection image ( 30 ) of the examination subject ( 15 . 17 ), S5) 2-D / 3-D-fusion ( 50 ) of the at least one 2-D projection image ( 31 ) and the registered volume dataset ( 23 ) for generating a 2-D overlay image ( 30 . 34 ), S6) Determination ( 51 ) of a first 2-D position ( 41 ) in at least one 2-D projection image ( 31 ), S7) Transmission of the determined first 2-D position ( 41 ) due to registration ( 47 ) according to method step S2) of the at least one 2-D projection image ( 31 ) to the volume data record ( 23 ) by means of rear projection ( 52 ) to determine a corresponding first 3-D position ( 43 ) in the volume data set ( 23 ), S8) calculation ( 53 ) of a 3-D dimension ( 45 ) along a course of the examination subject ( 15 . 17 ) characterizing line ( 25 ) between the first 3-D position ( 43 ) and a second 3-D position ( 44 ) and S9) output ( 54 ) of the 3-D dimension ( 45 ). An angiographic examination method according to claim 1, wherein the vascular system comprises at least two vessels ( 15 . 17 ) as an examination subject and the dimension of one at one in the region of a bifurcation ( 35 ) of the two vessels ( 15 . 17 ) introduced main stent ( 21 ) to be flanged ( 22 ) during an observation by means of the angiography system ( 2 to 4 ), characterized by the following modified or adapted steps: S1 ') generation ( 46 ) of a volume data set ( 23 ) of the at least two vessels ( 15 . 17 ), S2 ') Registration ( 47 ) of the volume data set ( 23 ) to the C-arm ( 2 ), S3 ') provision ( 48 ) of the course of the at least two vessels ( 15 . 17 ) in the volume data set ( 23 ), S4 ') generation ( 49 ) of at least one 2-D projection image ( 30 ) of the at least two vessels ( 15 . 17 ) with the introduced main stent ( 21 ), S5 ') 2-D / 3-D-fusing ( 50 ) of the at least one 2-D projection image ( 30 ) and the registered volume dataset ( 23 ) for generating the 2-D overlay image ( 30 . 34 ), in which the introduced main stent ( 21 ) and the pre-segmented volume data set ( 23 ) are anatomically correctly superimposed, S6 ') determination ( 51 ) of a position ( 41 ) of a first bifurcation ( 35 ) as the first 2-D position in at least one 2-D projection image ( 30 ), S7 ') Transmission of the determined 2-D position ( 41 ) due to registration ( 47 ) according to method step S2 ') of at least one 2-D projection image ( 30 ) to the volume data record ( 23 ) by means of rear projection ( 52 ) for determining the 3-D position ( 43 ) of this first bifurcation ( 35 ) in the volume data set ( 23 ), S8 ') calculation ( 53 ) the 3-D length of the vessel ( 15 . 17 ) as 3-D dimension ( 45 ) between the 3-D position ( 43 ) of the first bifurcation ( 35 ) and the end position of the partial stent to be inserted ( 22 ) as a second 3-D position ( 44 ) and S9 ') output ( 54 ) of the 3-D dimension ( 40 ) as the length of the partial stent to be selected and / or inserted ( 22 ). Angiographic examination method according to claim 1 or 2, characterized in that the volume data set ( 23 ) of the at least two vessels ( 15 to 17 ) according to the first method step before setting a main stent ( 21 ) and that the at least one 2-D projection image ( 30 ) according to the fourth method step after setting the main stent ( 21 ) be generated. Angiographic examination method according to one of claims 1 to 3, characterized in that the course of the examination subject ( 15 to 17 ) characterizing line the centerline ( 25 ). Angiographic examination method according to claim 4, characterized in that the course of the examination subject ( 15 to 17 ) characterizing centerline ( 25 ) by segmentation of the examination object ( 15 to 17 ) is determined. Angiographic examination method according to one of claims 1 to 5, characterized in that the first 2-D position ( 41 ) in the 2-D projection image ( 31 ) the position of the bifurcation ( 35 ) of the main stent ( 21 ) and / or that the second 3-D position ( 44 ) is a bifurcation Iliaca Interna and Externa. Angiographic examination method according to one of claims 1 to 6, characterized in that the determination of the first 2-D position ( 41 ) in the 2-D projection image ( 31 ) according to the sixth method step Pattern recognition process in the fluoroscopic image is done automatically. Angiographic examination method according to one of claims 2 to 7, characterized in that on the main stent ( 21 ) a mark is attached. Angiographic examination method according to one of claims 2 to 8, characterized in that on the main stent ( 21 ) A position sensor is mounted. Angiographic examination method according to one of claims 8 or 9, characterized in that the marker or the position sensor at the bifurcation ( 35 ) of the main stent ( 21 ) is attached. An angiographic examination method according to any one of claims 1 to 10, characterized in that the transmission of the determined 2-D position ( 41 ) according to method step S7 ') on the basis of the registration of the at least one 2-D projection image ( 30 ) to the volume data record ( 23 ) by a back projection ( 42 . 52 ) for determining the 3-D position ( 43 ) of this bifurcation ( 35 ) of the main stent ( 21 ) in the 3-D volume data set ( 23 ) he follows. Angiographic examination method according to one of claims 1 to 11, characterized in that the rear projection ( 42 . 52 ) of the specific 2-D position ( 41 ) in the 2-D projection image ( 31 ) into the volume data set ( 23 ) to the next point of the registered centerline ( 25 ) of the aorta ( 15 ) and / or the registered centerline ( 25 ) of the aorta ( 15 ) certain vessel level takes place. Angiographic examination method according to one of claims 1 to 12, characterized in that the rear projection ( 42 . 52 ) of the specific 2-D position ( 41 ) of several 2-D projection images ( 31 ) from different angulations. Angiographic examination method according to one of claims 1 to 13, characterized in that for the calculation ( 53 ) of the 3-D dimension ( 45 ) according to the eighth method step, the distance between the first 3-D position ( 43 ) and user preoperatively set landmarks as second 3-D positions ( 44 ) be calculated. Angiographic examination method according to one of claims 1 to 14, characterized in that for calculating a 3-D dimension ( 45 ) according to the eighth method step, the distance between the first 3-D position ( 43 ) and positions of intraoperatively introduced instruments is determined. An angiographic examination method according to any one of claims 1 to 15, characterized in that the volume data set ( 23 ) is a registered pre-operative MR angiography or computed tomography. An angiographic examination method according to any one of claims 1 to 16, characterized in that a segmentation ( 33 . 36 ) of the examination subject ( 15 to 17 ) in the reference image ( 27 ) he follows. Angiographic examination method according to one of claims 1 to 17, characterized in that the vessel in the region of the bifurcation an aorta ( 15 ) with the arteries Iliaca Communis ( 17 ) sinistra or dextra as bifurcation or an artery Iliaca communis sinistra or dextra with the arteries Iliaca externa and interna as bifurcation. An angiographic examination method according to any one of claims 1 to 18, characterized in that the main stent is an aortic stent ( 21 ) and the partial stent a iliac stent to be flanged ( 22 ) are. Angiographic examination method according to one of claims 1 to 19, characterized in that the 2-D projection images ( 31 ) Fluoroscopic live images, fluoroscopic images or DSA images are.

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