CATHETER LOCALIZATION SYSTEM

• US 20090076483A1
• Filed: 09/14/2007
• Published: 03/19/2009
• Est. Priority Date: 09/14/2007
• Status: Active Grant

• Current Assignee: Siemens Healthcare GMBH (Siemens AG)
• Original Assignee: Siemens AG
• Inventors: Danehorn, Kenneth
• Granted Patent: US 8,825,134 B2
• Time in Patent Office: Days
• US Class Current: 604/528
• CPC Class Codes: A61B 2034/2051 Electromagnetic tracking systems
• CPC Class Codes: A61B 2034/2053 Tracking an applied voltage gradient
• CPC Class Codes: A61B 34/20 Surgical navigation systems; Devices for tracking or guiding surgical instruments, e.g. for frameless stereotaxis
• CPC Class Codes: A61M 2025/0166 Sensors, electrodes or the like for guiding the catheter to a target zone, e.g. image guided or magnetically guided
• CPC Class Codes: A61M 25/01 Introducing, guiding, advancing, emplacing or holding catheters A61M25/10 takes precedence

Abstract

A system and method for localizing a catheter is provided. Distance values are determined between a plurality of reference electrodes and a catheter electrode. At least two circles are identified based on the distance values. The catheter electrode is located at a position where the at least two circles substantially coincide or within a minimum distance between the at least two circles. A transformation is applied to the at least two circles to express the at least two circles in a global coordinate system. An image is displayed as a function of the catheter electrode position.

Claims

1. A method for localizing a catheter, the method comprising:

determining distance values between a plurality of reference electrodes and a catheter electrode;

identifying at least two circles based on the distance values, the catheter electrode located at a position where the at least two circles substantially coincide or within a minimum distance between the at least two circles;

applying a transformation to the at least two circles to express the at least two circles in a global coordinate system; and

displaying an image as a function of the catheter electrode position.

2. The method of claim 1, wherein the transformation is an Euler transformation.

3. The method of claim 1, wherein determining the distance values includes determining an impedance or voltage potential.

4. The method of claim 1, wherein generating the at least two circles comprises determining an orthogonal distance within a triangle, dimensions of the triangle associated with the distance values, and the orthogonal distance being a radius for one of the at least two circles.

5. The method of claim 1, further comprising:

translating origins of the at least two circles to the catheter electrode position before the transformation.

6. The method of claim 1, further comprising:

repositioning the at least two circles, after the transformation; and

solving for a global coordinate value of the catheter electrode based on where the at least two circles substantially coincide or the minimum distance between the at least two circles.

7. The method of claim 1, further comprising:

registering the plurality of reference electrodes in the global coordinate system.

8. A system for localizing a catheter, the system comprising:

an electrode on a catheter;

a plurality of reference electrodes, each of the plurality of reference electrodes configured to transmit or receive a signal to or from the electrode, respectively; and

a processor operable to determine distance values between the plurality of reference electrodes and the electrode, wherein the processor is further operable to determine a position of the electrode with at least two circles based on the distance values and applying a transformation to the at least two circles.

9. The system of claim 8, wherein the transformation is an Euler transformation.

10. The system of claim 8, wherein the plurality of reference electrodes comprises at least four reference electrodes.

11. The system of claim 8, wherein the processor is operable to determine the distances values based on an electrical characteristic associated with the respective signal.

12. The system of claim 11, wherein the electrical characteristic comprises an impedance or voltage potential.

13. The system of claim 8, wherein generating the at least two circles comprises determining an orthogonal distance within a triangle, dimensions of the triangle associated with the distance values, and the orthogonal distance being a radius for one of the at least two circles.

14. The system of claim 8, wherein the processor is further operable to determine the position of the electrode by translating origins of the at least two circles to the catheter electrode position before the transformation.

15. The system of claim 8, wherein the processor is further operable to determine the position of the electrode by repositioning the at least two circles, after the transformation, and solving for a global coordinate value of the catheter electrode.

16. In a computer-readable medium having stored therein instructions executable by a processor, the instructions comprising:

determining distance values between a plurality of reference electrodes and a catheter electrode;

determining at least two circles based on the distance values wherein the catheter electrode is located at a position where the at least two circles are the closest; and

applying a transformation to the at least two circles, the transformed at least two circles being in a global coordinate system.

17. The instructions of claim 16, wherein the transformation is an Euler transformation.

18. The instructions of claim 16, wherein generating the at least two circles comprises determining an orthogonal distance within a triangle, dimensions of the triangle associated with the distance values, and the orthogonal distance being a radius for one of the at least two circles.

19. The instructions of claim 16, further comprising:

translating origins of the at least two circles to the catheter electrode position before the transformation.

20. The instructions of claim 16, further comprising:

repositioning the at least two circles, after the transformation; and

solving for a global coordinate value of the catheter electrode based on where the at least two circles are the closest.