Determining a Flow Characteristic of a Material in a Structure

• US 20090264777A1
• Filed: 04/13/2009
• Published: 10/22/2009
• Est. Priority Date: 04/18/2008
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Fleming, Loana, Receveur, Rogier, Markowitz, H. Toby, Falkner, Phillip, Warman, Eduardo N., Karamanoglu, Mustafa, Waldhauser, Steven L., Zhang, Shangqian Peter, Larik, Vincent, Michels, Koen, Eick, Olaf, Glese, Chad, Jannicke, Jeff, Scanlon, David A., Kryger, Michael, Campbell-Massa, Sean, Hefner, Don, Mehta, Pooja, Steeves, James
• Granted Patent: US 8,214,018 B2
• Time in Patent Office: Days
• US Class Current: 600/506
• 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 2017/00336 with a protective sleeve, e.g. retractable or slidable
• 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 2034/105 Modelling of the patient, e.g. for ligaments or bones
• CPC Class Codes: A61B 2090/376 using X-rays, e.g. fluoroscopy
• CPC Class Codes: A61B 2090/378 using ultrasound
• CPC Class Codes: A61B 2090/3983 Reference marker arrangements for use with image guided surgery
• 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 5/06 Devices, other than using radiation, for detecting or locating foreign bodies for removing same A61B17/50 ; determining position of probes within or on the body of the patient
• CPC Class Codes: A61B 5/061 Determining position of a probe within the body employing means separate from the probe, e.g. sensing internal probe position employing impedance electrodes on the surface of the body A61B1/00158 takes precedence
• CPC Class Codes: A61B 5/062 using magnetic field
• 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 5/287 : Holders for multiple electrodes, e.g. electrode catheters for electrophysiological study [EPS]
• CPC Class Codes: A61B 5/304 : Switching circuits
• CPC Class Codes: A61B 5/333 : Recording apparatus specially adapted therefor
• CPC Class Codes: A61B 5/339 : Displays specially adapted therefor
• CPC Class Codes: A61B 5/742 : using visual displays A61B5/339 takes precedence
• 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: A61B 8/4472 : Wireless probes

Abstract

An 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 flow of a material in a volume of a patient, comprising:

providing an instrument having a first position element and a flexible body member carrying a second position element operable to move due to a flow of a fluid in the volume;

placing the instrument into the volume and in contact with the fluid;

extending the second position element relative to the first position element such that the second position element extends a distance from the first position element;

determining a position of the second position element relative to the first position element due to a movement of the second position element relative to the first position element from fluid motion in the volume; and

displaying a representation of the determined position of the second position element relative to the first position element to illustrate a direction of fluid flow in the volume.

2. The method of claim 1, wherein placing the instrument into the volume of the patient includes placing the instrument into a fluid volume of a cardiovascular system of the patient.

3. The method of claim 1, further comprising:

providing a passage through a housing of the instrument;

placing the first position element on an exterior surface of the housing and in contact with the fluid; and

providing the flexible body member arranged to be movably positioned in the passage;

wherein extending the second position element relative to the first position element includes selectively extending a distal end of the flexible body member beyond the housing so as to extend the second position element a certain distance from the first position element.

4. The method of claim 3, further comprising:

determining a plurality of positions of the first and second position elements in the volume;

generating a map based on the determined plurality of positions; and

displaying the map on a display device;

determining a location within the patient based on the direction of flow of the material;

wherein displaying a graphical representation of the determined position of the second element position relevant to the first element position includes displaying a graphical representation on the displayed map indicative of a direction of movement of the second position element relative to the first position element to illustrate a direction of fluid flow in the volume.

5. The method of claim 3, wherein determining a position of the second position element relative to the first position element includes:

evaluating a first electrical property with the first position element;

determining a position of the first position element within the volume based on the evaluated first electrical property;

evaluating a second electrical property with the second position element; and

determining a position of the second position element relative to the determined position of the first position element based on the evaluated second electrical property.

6. The method of claim 5, wherein evaluating the first and second electrical properties includes determining an impedance at each of the first and second position elements at least by sensing a voltage at each of the first and second position elements and determining a current injected into the volume when the voltage was sensed.

7. The method of claim 5, wherein evaluating the first and second electrical properties includes sensing a respective voltage at the first position element and the second position element.

8. The method of claim 5, wherein displaying a graphical representation of the position of the second position element relative to the first position element includes:

displaying a graphical representation of the determined position of the first position element and the determined position of the second position element relative to the first position element; and

displaying an additional graphical representation indicative of a direction of fluid flow in the volume based on movement of the second position element relative to the first position element.

9. The method of claim 8, wherein the additional graphical representation includes an arrow pointing from the determined position of the first position element to determined position of the second position element to illustrate a direction of fluid flow in the volume.

10. The method of claim 5, wherein determining a position of the second position element relative to the first position element includes determining a plurality of positions of the second position element relative to the first position element;

and

wherein displaying a graphical representation of the determined position of the second position element relative to the first position element includes displaying a plurality of graphical representations indicative of a plurality of directions of fluid flow in the volume based on a plurality of movements of the second position element relative to the first position element.

11. The method of claim 5, further comprising:

providing at least one set of axis generation electrodes on an exterior surface of the volume, the at least one set of electrodes arranged to establish an axis via a conductive path therebetween; and

injecting a current into the volume between the at least one set of electrodes and generating a voltage gradient in the volume between the at least one set of electrodes;

wherein evaluating the first and second electrical properties includes sensing voltage at the first position element and the second position element between the at least one set of electrodes;

wherein determining the position of the first position element includes determining a position of the sensed voltage of the first electrical property along the voltage gradient between the at least one set of electrodes so as to provide a determined position of the first position element;

wherein determining the position of the second position element relative to the position of the first position element includes determining a position of the sensed voltage of the second electrical property along the voltage gradient between the at least one set of electrodes so as to provide a determined position of the second position element relative to the first position element.

12. The method of claim 5, further comprising:

providing three sets of axis generation electrodes on an exterior surface of the volume, each set of electrodes establishing an axis via a conductive path therebetween, each axis of the three sets of electrodes being substantially orthogonal to each other and intersecting at a common point; and

injecting a current into the volume between each set of electrodes and generating a voltage gradient in the volume between each set of electrodes;

wherein evaluating the first and second electrical properties includes sensing voltage at the first position element and the second position element between each set of electrodes;

wherein determining the position of the first position element includes determining a position of the sensed voltage of the first electrical property along the voltage gradients between each set of electrodes so as to provide a determined three dimensional position of the first position element;

wherein determining the position of the second position element relative to the position of the first position element includes determining a position of the sensed voltage of the second electrical property along the voltage gradients between each set of electrodes so as to provide a determined three dimensional position of the second position element relative to the first position element.

13. A system for determining a flow of material in a volume of a patient, comprising:

an instrument having a housing and a flexible body member, the housing including proximal and distal ends and an internal passage extending between the proximal and distal ends, the flexible body member arranged to be passed through the housing;

a first position element affixed to an exterior of the housing, wherein a portion of the housing is adapted to be placed in the volume so as to place the first position element in contact with a fluid in the volume of the patient; and

a second position element affixed to the flexible body member, wherein a distal end of the flexible body member is arranged to be selectively extended a certain distance beyond the distal end of the housing so as to place the second position element in contact with the fluid when the portion of the housing is positioned in the volume, the extended distal end of the flexible body member operable to flex due to a flow of the fluid in the volume;

wherein the first position element and the second position element are each arranged to sense an electrical property and provide data for determining a position of the first position element and a change in position of the second position element relative to the first position element, the change in position of the second position element relative to the first position element being indicative of the flow of the fluid in the volume.

14. The system of claim 13, wherein the first position element and the second position element are each arranged to sense a voltage in the volume.

15. The system of claim 14, further comprising:

a position sensing unit having at least one set of axis generation electrodes to inject a current into the volume, the at least one set of electrodes adapted to be positioned on an outer surface of the volume to establish an axis via a conductive path therebetween, the injected current generating a voltage gradient in the volume between the at least one set of electrodes; and

a processor coupled to the first and second position elements, the position sensing unit and a display device, the processor being operable to execute instructions to determine the position of the second position element relative to the first position element;

wherein the display device is arranged to display a graphical representation of the determined position of the second position element relative to the first position element to illustrate a direction of fluid flow in the volume.

16. The system of claim 15, wherein the processor is further operable to execute instructions to determine a plurality of positions of the first position element in the volume and generate a map based on the determined plurality of positions;

and

wherein the display device is arranged to display the map and to display the graphical representation of the determined position of the second position element relative to the first position element on the map.

17. The system of claim 15, wherein the processor is operable to determine a position of the first position element based on the sensed voltage along the voltage gradient and a position of the second position element based on the sensed voltage along the voltage gradient to determine the position of the second position element relative to the first position element.

18. The system of claim 15, wherein the processor is operable to determine an impedance based on the sensed voltage of the first position element along the voltage gradient and an impedance based on the second position element sensed voltage along the voltage gradient to determine the position of the second position element relative to the first position element.

19. The system of claim 15, wherein the at least one set of axis generation electrodes includes three sets of axis generation electrodes, each set of the three sets of axis generation electrodes establishing an axis via a conductive path therebetween, each axis of the three sets of electrodes positioned substantially orthogonal to each other and intersecting at a common point;

wherein the processor is operable to execute instructions to determine a three dimensional position of the second position element relative to a three dimensional position of the first position element; and

wherein the display device is arranged to display a graphical representation of the determined three dimensional position of the second position element relative to the first position element to illustrate a direction of fluid flow in the volume.

20. The system of claim 15, wherein the display of the graphical representation of the determined position of the second position element relative to the first position element includes:

a graphical representation of the determined position of the first position element and the determined position of the second position element relative to the first position element; and

an additional graphical representation indicative of a direction of fluid flow in the volume based on movement of the second position element relative to the first position element.

21. The system of claim 20, wherein the additional graphical representation includes an arrow pointing from the determined position of the first position element to determined position of the second position element to illustrate a direction of fluid flow in the volume.

22. The system of claim 14, wherein the first position element and the second position element each comprise an electrode.

23. The system of claim 13, wherein the internal passage of the housing further comprises an inner diameter and the flexible body member further comprises an outer diameter, the outer diameter of the flexible body member substantially matching the inner diameter of the passage.

24. The system of claim 13, wherein the first position element is affixed to the distal end of the housing and the second position element is affixed to the distal end of the flexible body member.

25. A method of determining flow of a material in a fluid filled volume of a patient, comprising:

providing an instrument having a first position element and a flexible body member carrying a second position element operable to move due to a flow of a fluid in the volume;

placing the instrument into the fluid filled volume and in contact with the fluid;

positioning the second position element relative to the first position element such that the second position element extends a distance from the first position element;

determining a first position of the first position element relative to a second position of the second position element due to a movement of the second position element relative to the first position element because of flow of the fluid in the fluid filled volume; and

determining a direction of flow of the fluid based on the determined first position relative to the determined second position.