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US-12622660-B2 - Determining a length of a stent

US12622660B2US 12622660 B2US12622660 B2US 12622660B2US-12622660-B2

Abstract

The length of a stent for a branched vessel may be determined without a contrast agent if possible. To this end, a method includes: acquiring a projection recording of the vessel into which an instrument has been introduced; determining the instrument in the projection recording; estimating a 3D reconstruction of the determined instrument from the projection recording in order to obtain a virtual 3D instrument; establishing a start point and an end point on the virtual 3D instrument with reference to an overlay of the virtual 3D instrument and the projection recording; and automatically determining a distance between the start point and the end point along the virtual 3D instrument as the length for the stent.

Inventors

  • Marcus Pfister

Assignees

  • Siemens Healthineers Ag

Dates

Publication Date
20260512
Application Date
20240909
Priority Date
20230915

Claims (17)

  1. 1 . A method for determining a length for a first stent for a branched vessel, the method comprising: acquiring a projection recording of the branched vessel into which an instrument has been introduced; determining the instrument in the projection recording; estimating a three-dimensional (3D) reconstruction of the determined instrument from the projection recording in order to obtain a virtual 3D instrument; establishing a start point and an end point on the virtual 3D instrument with reference to an overlay of the virtual 3D instrument and the projection recording; and automatically determining a distance between the start point and the end point along the virtual 3D instrument as the length for the first stent.
  2. 2 . The method of claim 1 , wherein the start point on the virtual 3D instrument is established with reference to an automatically identified opening of a second stent.
  3. 3 . The method of claim 2 , wherein the end point on the virtual 3D instrument is established with reference to an automatically identified branching of the branched vessel in the projection recording or in a 3D contour that is overlaid on the projection recording.
  4. 4 . The method of claim 3 , wherein the branched vessel comprises a femoral artery, and wherein the second stent is an aortic stent in an abdominal aorta, and wherein the branching is an iliac bifurcation.
  5. 5 . The method of claim 2 , wherein the branched vessel comprises a femoral artery, and wherein the second stent is an aortic stent in an abdominal aorta, and wherein a branching of the branched vessel is an iliac bifurcation.
  6. 6 . The method of claim 2 , wherein the second stent has a marking at the opening, and wherein the opening of the second stent is automatically identified with reference to the marking at the opening.
  7. 7 . The method of claim 2 , wherein the second stent has a 3D marker with reference to which the opening or a bifurcation of the second stent is configured to be localized in three dimensions.
  8. 8 . The method of claim 1 , wherein the end point on the virtual 3D instrument is established with reference to an automatically identified branching of the branched vessel in the projection recording or in a 3D contour that is overlaid on the projection recording.
  9. 9 . The method of claim 1 , wherein the establishing of the start point or the end point is effected by manually marking one or two corresponding positions.
  10. 10 . The method of claim 1 , wherein the projection recording is an only recording used for performing the 3D reconstruction of the determined instrument from the projection recording in order to obtain the virtual 3D instrument.
  11. 11 . The method of claim 1 , wherein the instrument is a catheter or a guide wire.
  12. 12 . The method of claim 11 , wherein the catheter is an angio-catheter.
  13. 13 . The method of claim 1 , wherein the virtual 3D instrument represents a virtual measuring catheter with measurement markings.
  14. 14 . The method of claim 1 , wherein the first stent is an iliac stent or an intracranial stent.
  15. 15 . The method of claim 1 , wherein the length for the first stent is a distance from an opening to a window or a distance between two windows of the first stent.
  16. 16 . The method of claim 1 , wherein a deformation of the branched vessel by the instrument is modeled and the start point and/or the end point are established with reference thereto.
  17. 17 . An arrangement for determining a length for a first stent for a branched vessel, the arrangement comprising: an acquisition device configured to acquire a projection recording of the branched vessel into which an instrument has been introduced; a detection device configured to determine the instrument in the projection recording; a computing device configured to estimate a three-dimensional (3D) reconstruction of the determined instrument from the projection recording in order to obtain a virtual 3D instrument; and a determining device configured to establish a start point and an end point on the virtual 3D instrument with reference to an overlay of the virtual 3D instrument and the projection recording, wherein the computing device is further configured to automatically determine a distance between the start point and the end point along the virtual 3D instrument as the length for the first stent.

Description

The present patent document claims the benefit of European Patent Application No. 23197566.5, filed Sep. 15, 2023, which is hereby incorporated by reference in its entirety. TECHNICAL FIELD The present disclosure relates to a method for determining a length for a stent for a branched vessel. The present disclosure further relates to a corresponding arrangement for determining the length. Furthermore, the present disclosure also relates to a corresponding computer program. BACKGROUND An abdominal aortic aneurysm (AAA) is a vascular dilation of the abdominal aorta. Such an AAA is treated by inserting various stent grafts (e.g., composite vascular stents). Guide wires and catheters are inserted into the aorta via both groins and are then used to insert a main (aortic) stent onto which stents for the femoral arteries (iliaca) are then “flange-mounted” (see, e.g., FIG. 3). In the case of more complex stents, known as fenestrated (having windows) or branched stents, further part stents are added. In order not to have to inject contrast agent for the continuous display of vessels for control purposes during the complex stent positioning, a reference image that shows the vessels (e.g., the aorta and vessels branching off the aorta) may be overlaid (e.g., in an anatomically correct manner) as a positioning aid (see, e.g., FIG. 4). A significant problem consists in determining the length of the iliac stents to be flange-mounted. This length may only be partly determined before the operation, even using a pre-segmented and measured data set. Although the length of the individual vessels may be known, (for example, as length of the center lines), the subsequent position of the femoral openings of the aortic stent that has been inserted is not known, and this is known only during the intervention (after depositing the stent), because the vessel is deformed by the stent that is inserted. In addition, the iliac arteries become significantly shorter as a result of the insertion of the rigid instruments (and stents). For example, measurements show that the deformation causes the length of the iliaca to be shortened from 66±12 mm preoperationally to 60±9 mm intra-operationally, (e.g., 6 mm on average). This shortening remains thereafter. In order to allow for both effects, it is standard practice, after inserting an aortic stent and probing the femoral opening with a (rigid) guide wire, to perform an angiography using a special angio-catheter with markings at 1-cm intervals. On the basis of “counting” the markings between iliac bifurcation (iliac fork) and bifurcation of the aortic stent that has been inserted, the length of the required iliac stent is then determined. In the publication DE 10 2013 219 737 B4, an angiographic examination method for depicting a target region inside a patient with a vascular system is developed in such a way that a three-dimensional correction facility is possible from just one projection image, thereby considerably improving the method sequence and radiation exposure for the patient. To this end an examination method is proposed having acts as follows: In act S1, a volume data set of the target region is acquired with the examination object. In act S2, the volume data set to the C-arm is registered. In act S3, information is extracted about an assumed course of the examination object in the volume data set inside the target region. In act S4, at least one 2D projection image of a medical instrument inserted in the target region is generated, which has a deviation between overlay and actually projected instrument. In act S5, the at least one 2D projection image and the registered volume data set are 2D/3D merged for generating a 2D overlay image. In act S6, the instrument inserted in the target region in the 2D overlay image is detected with a first projection matrix. In act S7, a virtual 2D projection is generated using a virtual projection matrix. In act S8, the instrument is 3D reconstructed, whereby a 3D position of the instrument is determined from the two projections. In act S9, the 2D projection image is overlayed with the virtual 2D projection, and at least one part of the 2D projection image is distorted such that the current and the assumed course of the vessels are brought into congruence. Using this approach, it is possible to perform the 3D reconstruction of rigid wires in 3D from a projection. The publication DE 10 2010 012 621 A1 describes an estimation method for determining a contour of a vessel which has been deformed for example by a rigid instrument (for example, guide wire). SUMMARY AND DESCRIPTION The object of the present disclosure is therefore to determine the length of a stent that is to be inserted and thereby to minimize the exposure of an object or patient to radiation or contrast agents. The scope of the present disclosure is defined solely by the appended claims and is not affected to any degree by the statements within this summary. The present embodiments may o