Mechanical modules of catheters for sensor fusion processes

Patent metadata

Field	Value
Publication number	US-11547492-B2
Application number	US-201916667070-A
Country	US
Kind code	B2
Filing date	Oct 29, 2019
Priority date	Nov 7, 2018
Publication date	Jan 10, 2023
Grant date	Jan 10, 2023

Abstract

Systems and methods are described for implementing a catheter model to estimate shape of a deformable catheter in a three-dimensional space. The catheter model includes two or more model segments that correspond to two or more segments of the deformable catheter. Each model segment includes a length and location of model electrode(s) and/or model magnetic sensor(s) corresponding electrodes and/or magnetic sensors of the deformable catheter. Variable shape parameter define a curvature of the segment. Varying the shape parameters generates a plurality of potential catheter shapes. In conjunction with generating the potential catheter shapes, impedance and/or magnetic responses (e.g., measured responses) are obtained for the physical electrodes and/or physical magnetic sensors of the deformable catheter. Using a selected one (e.g., most likely) of the potential catheter shapes and the measured responses, the shape parameters are updated and a catheter shape is generated and displayed.

First claim

What is claimed is:

1. A method for modeling a catheter and estimating catheter shapes, the method comprising:
defining a first model segment and a second model segment corresponding to first and second segments, respectively, of a deformable catheter disposed in a three-dimensional space, each model segment including a segment length and a location along the segment length of a model electrode or model magnetic sensor corresponding to a location of an electrode or magnetic sensor on a corresponding segment of the deformable catheter;
defining a first variable shape parameter for the first model segment and a second variable shape parameter for the second model segment, wherein the variable shape parameters describe curvatures of the first model segment and second model segment, respectfully;
varying, with a computer, the first and second variable shape parameters of the first and second model segments to generate a plurality of potential catheter shapes, where each potential catheter shape includes a model electrode location or a model magnetic sensor location;
obtaining a measured response of an electrode or a magnetic sensor of the deformable catheter while the deformable catheter is disposed in the three-dimensional space;
updating the variable shape parameters based on the measured response and a model electrode location or model magnetic sensor location from a selected one of the plurality of potential catheter shapes; and
generating a catheter shape based on the updating of the variable shape parameters and outputting the catheter shape to a display.

2. The method of claim 1 , for each segment, further comprising:
defining a plurality of model electrode locations along the length of at least one of the first and second model segments.

3. The method of claim 1 , where defining each of the variable shape parameters comprises:
defining a curvature and a torsion for each model segment.

4. The method of claim 1 , wherein the first model segment and the second model segment are continuous.

5. The method of claim 1 , wherein the first variable shape parameter has a first range of curvatures and the second variable shape parameter has a second range of curvatures.

6. The method of claim 1 , wherein modeling further comprises, for each model segment, defining a moving frame that follows an arc of the model segment.

7. The method of claim 6 , wherein the moving frame comprises a Frenet frame.

8. The method of claim 1 , wherein the plurality of catheter shapes are defined in a catheter reference frame.

9. The method of claim 8 , further comprising:
transforming the selected one of the plurality of catheter shapes from the catheter reference frame to a reference frame of the three-dimensional space; and
determining a predicted location of the model electrode of the catheter shape in the three-dimensional space.

10. The method of claim 9 , further comprising:
generating a predicted impedance response for predicted location of the model electrode in the three-dimensional space.

11. The method of claim 10 , wherein the predicted impedance response is utilized with the impedance response of the electrode of the deformable catheter as measured in the three-dimensional space to update the shape parameters.

12. The method of claim 1 , wherein the variable shape parameters comprise state variables, wherein varying the variable shape parameters comprises applying a transformation matrix to the state variables.

13. The method of claim 12 , wherein a Kalman Filter is used to infer the state variables.

14. The method of claim 12 , wherein the plurality of potential catheter shapes comprises a state distribution of potential catheter shapes.

15. The method of claim 14 , further comprising:
applying a function to the estimated state distribution to remove unlikely states from the estimated state distribution and generate an updated state distribution.

16. The method of claim 15 , wherein the selected one of the plurality of potential catheter shapes comprises a mean of the updated state distribution.

17. The method of claim 1 , further comprising:
based on the measured response and a model electrode location or a magnetic sensor location from the selected one the plurality of potential catheter shapes identifying a location of the electrode or the magnetic sensor in the three-dimensional space.

18. The method of claim 1 , wherein the updating of the variable shape parameters occurs at least 50 times per second.

19. A system for modeling a catheter and estimating shapes of the catheter, the system including:
a deformable catheter having an electrode and a magnetic sensor;
a medical positioning system to measure responses of the electrode and magnetic sensor in a three-dimensional space;
a processor and memory for storing non-transitory computer readable instruction to:
access a stored definition of first and second model segments corresponding to first and second segments, respectively of the deformable catheter disposed in a three-dimensional space, each model segment including a segment length and a location along the segment length of a model electrode or model magnetic sensor corresponding to a location of an electrode or magnetic sensor of the deformable catheter;
vary a first variable shape parameter for the first model segment and vary a second variable shape parameter for the second model segment, wherein the variable shape parameters describe curvatures of the first model segment and second model segment, respectfully;
generate a plurality of potential catheter shapes based on the varying of the variable shape parameters, where each potential catheter shape includes a model electrode location or model magnetic sensor location for the first and second model segments;
obtain a measured response of an electrode or a magnetic sensor of the deformable catheter while the deformable catheter is disposed in the three-dimensional space;
update the first and second shape parameters based on the measured response and a model electrode location or magnetic sensor location from a selected one of the plurality of potential catheter shapes; and
generate an updated catheter shape based on the update of the first and second shape parameters; and

a display configured to display the updated catheter shape.

20. The system of claim 19 , further comprising instructions to identify a location of the electrode or magnetic sensor in the three dimensional space based on the measured response a predicted impedance response for the model electrode location or a predicted magnetic response for the model magnetic sensor location.

Assignees

• St Jude Medical Int Holding Sarl
• St Jude Medical Int Holding Sa R L

Inventors

• Hill Anthony D
• Thompson Cable
• Malinin Yuriy
• Belk Paul
• Lundquist Eric
• Yoresh Maxim

Classifications

• A61B2017/00699

  correcting for movement caused by respiration, e.g. by triggering · CPC title

• A61B5/6858

  with a distal basket, e.g. expandable basket · CPC title

• A61B34/10 Primary

  Computer-aided planning, simulation or modelling of surgical operations · CPC title

• A61B5/063

  using impedance measurements · CPC title

• A61B5/721

  using a separate sensor to detect motion or using motion information derived from signals other than the physiological signal to be measured · CPC title