Determining a Material Flow Characteristic in a Structure

• US 20090262979A1
• 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: Scanion, David A., 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, Kryger, Michael, Campbell-Massa, Sean, Fleming, Ioana, Hefner, Don, Mehta, Pooja, Steeves, James
• Granted Patent: US 8,208,991 B2
• Time in Patent Office: Days
• US Class Current: 382/103
• 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 a flow of a material in a volume, comprising:

moving an instrument having a position element into the volume;

evaluating an electrical property with the position element at a first time;

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

evaluating the electrical property with the position element at a second time later than the first time;

determining a second position of the position element within the volume based on the evaluated electrical property at the second time;

determining a change in position between the determined first position at the first time and the determined second position at the second time to determine a flow of material in the volume; and

displaying a graphical representation of the determined change in position between the determined first position and the determined second position to illustrate a direction of the flow of material.

2. The method of claim 1, wherein evaluating the electrical property includes determining an impedance at the position element at least by sensing a voltage at the position element and determining a current injected into the volume when the voltage was sensed.

3. The method of claim 1, wherein determining a change in position includes determining a change in position between the determined first position at the first time and the determined second position at the second time to determine a flow of blood in a heart.

4. The method of claim 3, further comprising identifying congenital abnormalities based on the determined flow of blood in the heart.

5. The method of claim 3, further comprising determining a location of the coronary sinus ostium based on the determined flow of blood in the heart to determine a lead implantation site.

6. The method of claim 1, wherein displaying a graphical representation of the determined change in position includes:

displaying a graphical representation of the first and second determined positions; and

displaying an additional graphical representation indicative of the direction of the flow of material in the volume from the determined first position to the determined second position.

7. The method of claim 6, wherein displaying the additional graphical representation indicative of direction includes displaying an arrow pointing from the determined first position to the determined second position.

8. The method of claim 1, wherein moving the position element into the volume includes:

fixing a proximal end of the instrument;

placing the position element in contact with a conductive medium in the volume; and

allowing the position element to move in a flow of material within the volume relative to the fixed proximal end of the instrument.

9. The method of claim 8, further comprising:

providing three sets of axis generation electrodes on an exterior surface of the volume, each set of electrodes spaced apart and arranged to establish 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;

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

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

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

10. The method of claim 9, further comprising determining a rate of movement of the position element from the determined first position to the determined second position at least by determining a distance between the determined first and second positions and an elapsed amount of time between determining the first position at the first time and determining the second position at the second time.

11. The method of claim 9, wherein displaying a graphical representation of the determined change in position includes:

displaying a graphical representation of the first and second determined positions; and

displaying an additional graphical representation indicative of a direction of flow of the material in the volume from the determined first position towards the determined second position.

12. The method of claim 1, further comprising providing a selectively inflatable member on a portion of the instrument arranged to be moved into the volume, and wherein the selectively inflatable member is arranged to be inflated prior to determining the first and second positions with the position element to cause a drag to facilitate determining flow direction.

13. The method of claim 1, further comprising:

providing a selectively inflatable member on a portion of the instrument arranged to be moved into the volume; and

inflating the inflatable member after determining the first position at the first time and prior to determining the second position at the second time with the position element.

14. The method of claim 1, further comprising:

providing map data of at least a portion of an inner surface of the volume; and

wherein determining a change in position between the first and second determined positions includes;

determining a first distance between the first determined position and a point from the surface map data;

determining a second distance between the second determined position and the point from the surface map data; and

determining a difference between the determined first and second distances.

15. The method of claim 14, wherein displaying the graphical representation of the determined change in position includes displaying a graphical representation indicative of a movement from the determined first position to the determined second position.

16. The method of claim 14, wherein displaying a graphical representation of the determined change in position includes:

displaying a graphical representation of the first and second determined positions; and

displaying an additional graphical representation indicative of the direction of the flow of material in the volume from the determined first position to the determined second position.

17. A method of determining a flow of a material in a volume, comprising:

providing an instrument having a position element on an exterior of a first portion of the instrument arranged to be moved into the volume;

moving the first portion of the instrument into the volume and placing the position element in contact with a flowing conductive medium in the volume;

fixing a second portion of the instrument relative to the first portion;

providing three sets of axis generation electrodes on an exterior surface of the volume, each set of electrodes spaced apart and arranged to establish 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;

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

sensing a first voltage at the position element between each set of the three sets of electrodes at a first time;

determining a first position of the position element based on the sensed first voltage along the voltage gradients of each of the three sets of electrodes so as to provide a determined three dimensional first position of the position element at the first time;

sensing a second voltage at the position element between each set of the three sets of electrodes at a second time later than the first time;

determining a second position of the position element based on the sensed second voltage along the voltage gradients of each of the three sets of electrodes so as to provide a determined three dimensional second position of the position element at the second time;

determining a change in position between the determined first and second positions of the position element; and

displaying a graphical representation of the determined change in position between the first and second determined positions that indicates a direction of flow of the conductive medium in the volume from the first to the second determined position.

18. The method of claim 17, further comprising providing a selectively inflatable member on the portion of the instrument arranged to be moved into the volume, and wherein the selectively inflatable member is arranged to be inflated prior to determining the first and second positions of the position element to cause a drag to facilitate determining flow direction.

19. The method of claim 17, further comprising determining a rate of movement of the position element from the determined first position to the determined second position at least by determining a distance between the determined first and second positions and an elapsed amount of time between determining the first position and determining the second position.

20. The method of claim 17, wherein fixing a second portion of the instrument relative to the first portion includes holding static the second portion of the instrument arranged to remain outside the volume after moving the first portion of the instrument into the volume.

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

an instrument having a position element and a selectively inflatable member each positioned on a portion of the instrument arranged to be moved into the volume so as to place the inflatable member and the position element in contact with a flowing conductive medium in the volume;

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 position element, the position sensing unit and a display device;

wherein the position element is arranged to sense a first voltage and a second voltage along the voltage gradient between the at least one set of electrodes and communicate the sensed first and second voltages to the processor, the processor is arranged to determine respective first and second positions of the position element based on the first and second sensed voltages along the voltage gradient and to determine a change in position of the position element between the determined first and second positions to determine a flow of material in the volume;

wherein the display device is arranged to display a graphical representation of the flow of material in the volume between the determined first and second positions.

22. The system of claim 21, wherein the processor is further arranged to determine a rate of movement of the position element from the determined first position to the determined second position at least by determining a distance between the determined first and second positions and an elapsed amount of time between determining the first position and determining the second position.

23. The system of claim 21, wherein the processor is arranged to determine the flow of material in the volume using only the instrument and the position sensing unit.