Patent Application
20120089003
This disclosure relates to the prior art fields of registration of 2D and 3D images; CPR visualization of vessels; and localizing catheters and guide wires (or other instruments) in 2D images.
More particularly this disclosure relates to the prior art field of fluoroscopy controlled, interventional repair of Abdominal Aortic Aneurysms (AAA), which is a disease of the abdominal aorta. See prior art FIGS. 1A,B,C. This disease is usually treated by inserting stent grafts 10 into the aorta 11 to remodel the organ. Through the groin arteries 13, guide wires 12 and catheters are inserted through which one or more stent grafts 10 are placed (FIGS. 1A,B,C).
Important for the delivery of these grafts is to stay in a determined “landing zone”. The object is to place the stent in a healthy area without occluding any important vessel branches, like e.g. the renal arteries. A sensitive point during the intervention is the release of the main stent in the aorta (
To not have to inject contrast medium permanently to control this complex stent positioning, as shown in FIG. 2A,B,C it is possible in a known method to overlay a registered 3D volume 15 showing the (segmented) relevant part 14 (aneurysm) of the aorta 11 (FIG. 1A,B,C) to guide the positioning of the stent 10 (
Thus prior art FIGS. 2A,B show a 2D3D overlay. If the 3D volume 15 is registered to the C-Arm and the projection geometry of the C-Arm is known (
A visualization problem can be that during this overlay the aorta may look different than in the diagnostic images the physician usually uses for planning the intervention. For planning purposes, the 3D image information gets displayed as so called “Curved MPRs (Multi-Planar Reconstruction) (CPRS (Curved Planar Reconstruction))” (see Armin Kanitsar, Dominik Fleischmann, Rainer Wegenkittl, Meister Eduard Gröller, “Diagnostic Relevant Visualization of Vascular Structures”, Technical Report TR-186-2-04-02, Jan. 20, 2004, TU Vienna). Prior art FIGS. 3A,B,C basically provide a standardized view on the organ by straightening the aorta 17. See prior art
Prior art FIGS. 3A,B,C thus show possibilities to visualize the aorta.
It is an object to provide an adaption of the 2D3D overlay which reformats the 2D fluoro similar to a curved planar reconstruction (CPR). The method gives the physician a standardized view on the overlay of the segmented aorta, comparable to what is already know from diagnostic CT.
In a method for a fluoroscopy controlled insertion of a stent into a curved aorta of a patient for aneurysm repair, a 3D volume image is obtained of the patient's aorta at the aneurysm. By knowing a registration of the 3D volume image to a C-arm of an angiographic system and projection geometry of the angiography system, the 3D volume image is projected anatomically correct to a 2D fluoroscopy image of the angiography system. For the 2D3D overlay, the 3D volume image is displayed as a curved planar reconstruction in which the 2D fluoroscopy image and the 3D volume image are warped around a curved center line of the patient's curved aorta or around a curved guide instrument center line to correct for the curvature of the aorta so that the previously curved aorta center line or curved center line of the guide instrument turns into a straight line. The 2D3D overlay is used to visualize the insertion of the stent.
FIGS. 1A,B,C show insertion of a stent graft into an aorta;
FIGS. 2A,B show a 2D3D overlay;
FIGS. 3A,B,C show various ways to visualize the aorta;
FIGS. 4A,B illustrate a first preferred embodiment with a CPR based 2D3D overlay having warping;
FIGS. 6A,B show a second preferred embodiment with a CPR based 2D3D overlay having warping;
FIGS. 8A,B,C show a direct comparison of the first preferred embodiment method and the second preferred embodiment method;
FIGS. 9A,B,C show an extension of the CPR overlay to an entire AAA segmentation.
For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the preferred embodiments/best mode illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, and such alterations and further modifications in the illustrated device and such further applications of the principles of the invention as illustrated as would normally occur to one skilled in the art to which the invention relates are included.
Two main methods are disclosed and described in the following. The methods are described for abdominal aortic aneurysms but can of course be extended to any case where CPR reformatting is usually applied, e.g. thoratic aneurysms.
Preconditions for both methods are a calibrated C-Arm Angio System (like the prior art Siemens Zee systems); and a 3D volume of the aorta which is registered to the C-Arm.
The first preferred method embodiment (FIGS. 4A,B) adapts the 2D3D overlay to the usual CPR visualizations for CT. Therefore additionally the center line 19 of the aorta 40A needs to be known. Then, because of the registration, the projection of this center line 19 onto the 2D fluoro image (curved line 19 in (
Thus FIGS. 4A,B illustrate a CPR based 2D3D overlay of the first method. They show a first preferred embodiment method wherein the physician is given a standardized view on the overlay of the segmented aorta, comparable to what is already know from the diagnostic CT.
Because of the segmentation, the center line 19 of the aorta 40A (which will be overlaid to fluoro) is known, and of course with it the projection of this center line onto the 2D fluoro image (line 19 in
The flowchart of
The second approach (FIGS. 6A,B) accounts for the bended guide device 25A (such as an insertion catheter 25A or a guide wire) rather than for the aorta itself but still uses a similar warping. The method is to give the physician a more precise view of the expanding stent graft. Here it is assumed that the inserted curved guide device 25A (catheter) can be recognized (and tracked) in the 2D fluoro image as curved center line 21 in
Thus FIGS. 6A,B show a CPR based 2D3D overlay according to the second embodiment method which provides for the bended guide device 25A (such as a catheter) to give the physician a more precise view on the expanding stent graft. This second method assumes the inserted curved guide device 25A (catheter) can be recognized in the 2D fluoro images and has a curved center line 21 in
Method steps of the second preferred embodiment will now be described with respect to the flowchart of
FIGS. 8A,B,C show a direct comparison of the first method (FIGS. 8A,B) and the second method (FIGS. 8A,C).
Since generally not only the center line of the aorta of the AAA will be curved and can be straightened, but also the center line of all branches will have curvatures in 3D, an extension as shown in FIGS. 9A,B,C can be applied to the above methods. Here, the method is to straighten all of the AAA center lines shown in
Thus FIGS. 9A,B,C show an extension of the CPR overlay to the entire AAA segmentation.
The following advantages result from the two preferred methods. The proposed reformatting of the 2D3D overlay image allows the physician, during a 2D3D image guided procedure, a standardized view on the overlay of the segmented aorta, comparable to what is already know from the diagnostic CT.
Although preferred exemplary embodiments are shown and described in detail in the drawings and in the preceding specification, they should be viewed as purely exemplary and not as limiting the invention. It is noted that only preferred exemplary embodiments are shown and described, and all variations and modifications that presently or in the future lie within the protective scope of the invention should be protected.
