TRACKING A GUIDE MEMBER

• US 20090264746A1
• Filed: 04/15/2009
• Published: 10/22/2009
• Est. Priority Date: 04/18/2008
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc), Regents of The University of Minnesota (University of Minnesota)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Phillips, Lane A., Receveur, Rogier, Markowitz, H. Toby, Falkner, Phillip, Warman, Eduardo N., Karamanoglu, Mustafa, Waldhauser, Steven L., Zhang, Shangqian Peter, Larik, Vincent, Michels, Koen, Giese, Chad, Eick, Olaf, Craig, Brian Houston, Interrante, Victoria, Kryger, Michael, Campbell-Massa, Sean, Smith, Marie P., Fleming, Ioana, Scanlon, David, Hurtig, Noelle Christine, Chelgren, Brent, Mehta, Pooja, Nowak, Karl Evan, Steeves, James
• Granted Patent: US 8,887,736 B2
• Time in Patent Office: Days
• US Class Current: 600/424
• CPC Class Codes: A61B 2017/00022 Sensing or detecting at the treatment site
• CPC Class Codes: A61B 2017/00026 Conductivity or impedance, e.g. of tissue
• CPC Class Codes: A61B 2017/00053 Mapping
• CPC Class Codes: A61B 2017/00084 Temperature
• CPC Class Codes: A61B 2017/00243 cardiac
• CPC Class Codes: A61B 2017/22051 with an inflatable part, e.g. balloon, for positioning, blocking, or immobilisation A61B2017/22048, A61B2017/3486 take precedence
• CPC Class Codes: A61B 2034/102 Modelling of surgical devices, implants or prosthesis
• CPC Class Codes: A61B 2034/105 Modelling of the patient, e.g. for ligaments or bones
• CPC Class Codes: A61B 2034/2051 Electromagnetic tracking systems
• CPC Class Codes: A61B 2034/2068 using pointers, e.g. pointers having reference marks for determining coordinates of body points
• CPC Class Codes: A61B 2034/2072 Reference field transducer attached to an instrument or patient
• CPC Class Codes: A61B 2090/061 for measuring dimensions, e.g. length
• CPC Class Codes: A61B 2090/063 for measuring volume
• CPC Class Codes: A61B 2090/371 with simultaneous use of two cameras
• CPC Class Codes: A61B 2090/376 using X-rays, e.g. fluoroscopy
• CPC Class Codes: A61B 2090/378 using ultrasound
• CPC Class Codes: A61B 34/20 Surgical navigation systems; Devices for tracking or guiding surgical instruments, e.g. for frameless stereotaxis
• CPC Class Codes: A61B 34/25 User interfaces for surgical systems
• CPC Class Codes: A61B 5/05 Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves impedance plethysmography A61B5/0295; measuring movement of the entire body or parts thereof A61B5/11; detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof A61B5/24
• CPC Class Codes: A61B 5/053 Measuring electrical impedance or conductance of a portion of the body
• CPC Class Codes: A61B 5/0538 : invasively, e.g. using a catheter
• CPC Class Codes: A61B 5/063 : using impedance measurements
• CPC Class Codes: A61B 5/066 : Superposing sensor position on an image of the patient, e.g. obtained by ultrasound or x-ray imaging
• CPC Class Codes: A61B 5/068 : using impedance sensors
• CPC Class Codes: A61B 5/287 : Holders for multiple electrodes, e.g. electrode catheters for electrophysiological study [EPS]
• CPC Class Codes: A61B 8/06 : Measuring blood flow measuring volume flow in general G01F, e.g. G01F1/66, G01F1/72; measuring speed of fluids in general G01P5/00
• CPC Class Codes: G06T 19/003 : Navigation within 3D models or images

Abstract

A volume of a patient can be mapped with a system operable to identify a plurality of locations and save a plurality of locations of a mapping instrument. The mapping instrument can include one or more electrodes that can sense a voltage that can be correlated to a three dimensional location of the electrode at the time of the sensing or measurement. Therefore, a map of a volume can be determined based upon the sensing of the plurality of points without the use of other imaging devices. An implantable medical device can then be navigated relative to the mapping data.

Claims

1. A method of determining a position of an elongated member in a volume filled with a conductive medium, comprising:

positioning a set of axis electrodes on a surface of the volume;

driving a current between the set of axis electrodes;

positioning an elongated conductive member within the volume;

determining a single value of an electrical property generated along the length of the elongated conductive member;

determining a position within the volume related to the single value; and

determining a position of a center of the elongated conductive member based on the determined position.

2. The method of claim 1, further comprising displaying an icon on a display device representing the determined position of the center of the elongated member.

3. The method of claim 2, wherein determining a position of a center of the elongated conductive member includes estimating a position of the elongated conductive member based upon the determined single value of the electrical property regarding a length of the elongated member being entirely and completely exposed to the conductive median in the volume.

4. The method of claim 1, further comprising determining a position of a distal end of the elongated member based on the determined position of the center of the elongated member and an insertion point of the elongated member into the volume.

5. The method of claim 4, further comprising:

determining an insertion location of the elongated conductive member into the volume;

determining a straight line from the insertion point through the determined position of a center of the elongated conductive member;

determining a distance from the insertion point to the determined position of a center of the elongated conductive member;

defining the distal end of the elongated conductive member as twice the determined distance along the defined line; and

displaying on a display device the determined position of the distal end of the elongated conductive member.

6. The method of claim 5, further comprising:

maintaining the elongated conductive member in a substantially linear configuration.

7. The method of claim 5, further comprising:

displaying a map of the volume; and

manually identifying the insertion location on the map.

8. The method of claim 5, wherein determining the insertion location includes determining an initial value of the electrical property as the elongated conductive member immediately enters the conductive medium of the volume.

9. The method of claim 5, further comprising:

moving the elongated conductive member through a catheter;

determining a value of the electrical property with a position element at a distal opening of the catheter; and

passing the elongated conductive member out of the distal opening of the catheter;

wherein determining the insertion location includes determining a position of the position element at the distal opening of the catheter based on the determined value of the electrical property at the position element at the distal opening of the catheter.

10. The method of claim 5, further comprising:

displaying on a display device a map of the volume;

displaying at least one of an insertion icon representing the insertion location and a distal end icon representing a distal end of the elongated member.

11. A method of determining a position of an elongated member in a volume filled with a conductive medium, comprising:

positioning at least three sets of axis electrodes on a surface of the volume;

driving a current between each of the sets of axis electrodes to generate three axes of current substantially orthogonal within the volume of a heart;

positioning an elongated conductive member within the heart;

determining an insertion position of the elongated conductive member;

determining a single value of an electrical property generated along the length of the elongated conductive member;

determining a position within the heart related to the single value;

determining a position of a center of the elongated conductive member based on the determined position; and

determining a position of a distal end of the elongated conductive member based on both the determined insertion position and the determining a position of a center of the elongated conductive member.

12. The method of claim 11, wherein determining a single value of an electrical property include sensing a voltage along each of the three axes generated within the volume of the heart.

13. The method of claim 12, further comprising:

determining an impedance based on the sensed voltage, wherein determining a position within the heart includes determining a position based on at least one of the sensed voltage or the determined impedance; and

displaying the determined position superimposed on a map of the heart on a display device.

14. The method of claim 13, further comprising:

displaying on the display device at least a distal end icon representing the location of the distal end of the elongated conductive member;

wherein determining a position of the distal end of the elongated conductive member includes determining a point on a line that extends from the determined insertion position to the determined position of the center of the elongated conductive member and twice a distance between the determined insertion position and the determined position of the center of the elongated conductive member.

15. The method of claim 14, further comprising:

updating the display of the distal end icon based on an updated determination of a single value of the electrical property generated along the length of the elongated conductive member;

wherein the determined single value changes based on the position of the elongated conductive member relative to each of the three axes.

16. The method of claim 11, wherein determining an insertion position includes at least one of:

manually identifying an insertion position;

initially determining the value of the electrical property as the elongated member enters the conductive median of the heart; and

determining a catheter distal tip position based upon determining a value of the electrical property at a position element fixed at a distal end of the catheter.

17. The method of claim 11, further comprising moving an implant device over the elongated conductive member to a selected location identified by determining a position of the distal end of the elongated conductive member.

18. A system to determine a position of an elongated member in a volume filled with a conductive medium, comprising:

a position sensing unit, including;

at least three sets of axis electrodes operable to be positioned on a surface of the volume;

a driver to inject a current between each of the sets of axis electrodes to generate three substantially orthogonal axes of current within the volume of a heart;

a processor;

an elongated conductive member extending to a distal end and operable to extend from an insertion point to a position within the heart;

a display device operable to display a determined position of the elongated member within the heart;

wherein the processor is operable to determine a single value of an electrical property along a length of the elongated conductive member;

wherein the processor is further operable to determine a position within the heart related to the single value;

wherein the processor is further operable to determine a position of a center of the elongated conductive member based on the determined position; and

wherein the processor is further operable to determine a position of a distal end of the elongated conductive member based on both the determined insertion position and the determining a position of a center of the elongated conductive member.

19. The system of claim 18, further comprising:

a memory system operable to store a plurality of positions within the heart;

wherein the processor is operable to generate a map of the heart based on the stored plurality of positions;

wherein the display device is operable to display at least one of a center icon illustrating a position of the center of the elongated conductive member superimposed on the map and a distal end icon illustrating a position of the distal end of the elongated conductive member superimposed on the map.

20. The system of claim 19, wherein the processor is operable to determine the distal end icon position as a point on a line extending from the insertion point through the determined center of the elongated conductive member and a distance from the insertion point that is twice a distance between an insertion position of the elongated conductive member and the determined position of a center of the elongated conductive member and.

21. The system of claim 18, further comprising:

an implant device operable to be moved over the elongated conductive member into a position within the heart based upon the determined position of the distal end of the elongated conductive member.