Correcting for distortion in a tracking system

• US 8,185,192 B2
• Filed: 04/15/2009
• Issued: 05/22/2012
• 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), Regents of The University of Minnesota (University of Minnesota)
• Inventors: Markowitz, H. Toby, Scanlon, David, Karamanoglu, Mustafa, Nowak, Karl Evan, Giese, Chad
• Primary Examiner(s): Gedeon, Brian T
• Application Number:
  US12/423,994
• Publication Number:
  US 20090265128A1
• Time in Patent Office: 1,133 Days
• Field of Search: 600/374, 600/523, 600/547, 606/41, 607/101, 607/111, 607/122
• US Class Current: 600/523
• 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 system for correcting distortion in an electro-potential position sensing system, comprising;

at least two electrodes operable to be positioned on a surface of a volume;

a driver to inject a current between the at least two electrodes to generate a current along an axis;

a mapping instrument operable to be positioned in a volume having a first electrode and a second electrode;

a processor operable to receive input from the first electrode and the second electrode fixed to the mapping instrument;

a storage system; and

a display device;

wherein the processor is operable to execute instructions to;

determine a first position of the first electrode and a second position of a second electrode on the instrument;

determine a vector from the first electrode on the instrument to the second electrode on the instrument based on the determined first position and second position;

determine a corrected map data point as a point a distance from the determined first position, wherein the distance is related to a physical distance of the first electrode from the second electrode on the instrument, wherein the corrected map data point is related to the determined first position;

wherein the storage system is operable to store a plurality of first positions and related corrected map data.

2. The system of claim 1, wherein the storage system is operable to store uncorrected map data of only a plurality of determined first positions and related determined second positions.

3. The system of claim 2, further comprising:

an input system;

wherein a user is operable to input to the processor to switch between a display on the display device an uncorrected map based only on the uncorrected map data and a corrected map based only on the stored a plurality of first positions and related corrected map data.

4. A system for correcting distortion in an electro-potential position sensing system, comprising;

at least two electrodes operable to be positioned on a surface of a volume;

a driver to inject a current between the at least two electrodes to generate a current along an axis;

an instrument operable to be positioned in the volume having a first electrode and a second electrode; and

a processor operable to receive input from the first electrode and the second electrode fixed to the instrument, wherein the processor is operable to execute instructions for;

determining a first position of a first electrode on the instrument;

determining a second position of a second electrode on the instrument;

determining a vector from the first electrode on the instrument to the second electrode on the instrument based on the determined first position and second position;

selecting a distance value from the first electrode;

plotting a corrected map data point as a point at the selected distance from the first position; and

collecting a plurality of first positions.

5. The system of claim 4, wherein the processor executing instructions for selecting a distance value from the first electrode includes determining a distance between the first position and the second position of the first electrode and second electrode, respectively, on the instrument.

6. The system of claim 4, wherein the first electrode is a predetermined fixed distance from the second electrode on the instrument and the processor executing instructions for selecting a distance value from the first electrode includes recalling the predetermined fixed distance.

7. The system of claim 4, wherein the processor executing instructions for determining the first position of the first electrode includes sensing an electrical property based on the injected current into the volume and determining the second position of the second electrode includes sensing the electrical property at the second electrode based on the injected current;

wherein the processor executing instructions for determining a vector from the first electrode to the second electrode includes determining a vector based upon the determined first and second positions of the first and second electrodes upon determining the electrical property at the first and second electrodes due to the injected current.

8. The system of claim 7, further comprising:

wherein the processor executing instructions for plotting a corrected map data point includes plotting a plurality of corrected map data points based on the plurality of collected first positions; and

wherein the processor is operable to execute further instructions for rendering a map based on the collected plurality of first positions and plotted plurality of corrected map data points.

9. The system of claim 8, wherein the processor is operable to execute further instructions for rendering a surface based on the collected plurality of first positions and plotted plurality of corrected map data points.

10. The system of claim 8, wherein the processor is operable to execute further instructions for:

generating an uncorrected map based on only the collected plurality of determined first positions and a collected plurality of second positions that are different than the collected plurality of determined first positions; and

generating a corrected map based only on the collected plurality of determined first positions and the plotted plurality of corrected map data.

11. The system of claim 10, further comprising:

a display device, wherein a display on the display device can selectively display at least one of the generated uncorrected map or the generated corrected map.

12. The system of claim 4, wherein the at least two electrodes operable to be positioned on a surface of a volume includes at least three pairs of electrodes positioned on the surface of the volume;

wherein the driver is operable to inject current between any selected pair of the at least three pair of electrodes to define at least three axes;

wherein the processor operable to execute instructions for determining a first position of a first electrode on the instrument includes sensing an electrical property based on the injected current along each of the three axes;

wherein the processor operable to execute instructions for determining a second position of a second electrode on the instrument includes sensing an electrical property based on the injected current along each of the three axes.

13. The system of claim 12, wherein the processor operable to execute instructions for collecting a plurality of first positions and plotting corrected map data points includes collecting a plurality of first positions in three dimensions and collecting a plurality of corrected map data in three dimensions.

14. A system for correcting distortion in an electro-potential position sensing system, comprising:

at least two electrodes operable to be positioned on a surface of a volume;

a driver to inject a current between the at least two electrodes to generate an current along an axis;

a instrument operable to be positioned in the volume having a first electrode and a second electrode;

a storage system; and

a processor operable to receive input from the first electrode and the second electrode fixed to the instrument, wherein the processor is operable to execute instructions for;

determining a vector from the first electrode on the instrument to the second electrode on the instrument based on determining a first initial position of the first electrode on the instrument and determining a second initial position of the second electrode on the instrument;

determine a distance value from the first electrode to the second electrode based on the first initial position and second initial position;

storing the determined distance value with the storage system; and

collecting map data by determining a first map data position of the first electrode based on a sensed electrical property due to the injected current and a second map data position based on a point that is the determined distance value along the vector from the first map data point.

15. The system of claim 14, wherein the at least two electrodes operable to be positioned on a surface of a volume includes at least three pairs of electrodes positioned on the surface of the volume;

wherein the driver is operable to inject current between any selected pair of the at least three pair of electrodes to define at least three axes;

wherein the determined first initial position and the determined second initial position includes determining the first initial position in three dimensions and determining the second initial position in three dimensions.

16. The system of claim 15, wherein the processor operable to execute instructions for collecting map data by determining the first map data position of the first electrode based on the sensed electrical property due to the injected current and the second map data position based on a point that is the determined distance along the vector from the first map data point includes determining a plurality of first map data positions of the first electrode and collecting a plurality of second map data positions;

and

wherein the processor is operable to execute further instructions for generating a corrected map based on the collected map data.

17. The system of claim 16, wherein the processor is operable to execute further instructions for determining the vector for each of the determined first map data positions of the first electrode.

18. The system of claim 14, wherein the processor is operable to execute further instructions for:

collecting a plurality of uncorrected positions of the first electrode and a plurality of uncorrected positions of the second electrode; and

generating an uncorrected map based on the uncorrected positions of the first electrode and the uncorrected positions of the second electrode.

19. The system of claim 18, wherein the processor is operable to execute further instructions for:

generating a corrected map based on the collected map data.

20. The system of claim 18, further comprising:

a display device,

wherein the display device is configured to have a display changed between the corrected map and the uncorrected map.