MEDICAL DEVICE POSITION LOCATION SYSTEMS, DEVICES AND METHODS

• US 20160320210A1
• Filed: 04/29/2016
• Published: 11/03/2016
• Est. Priority Date: 04/29/2015
• Status: Active Grant

• Current Assignee: Teleflex Life Sciences LLC (Teleflex Incorporated)
• Original Assignee: Nostix, LLC (Teleflex Incorporated)
• Inventors: Nelson, Peter E., Zellers, Robert D., Henry, Charles W.
• Granted Patent: US 10,098,567 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 2562/0223 Magnetic field sensors
• CPC Class Codes: A61B 2562/04 Arrangements of multiple sensors of the same type
• CPC Class Codes: A61B 5/062 using magnetic field
• CPC Class Codes: A61B 5/25 Bioelectric electrodes therefor
• CPC Class Codes: A61B 5/7225 Details of analog processing, e.g. isolation amplifier, gain or sensitivity adjustment, filtering, baseline or drift compensation A61B5/30, A61B5/316 take precedence; transformers for specific applications H01F38/00; amplifiers H03F
• CPC Class Codes: A61B 5/7425 Displaying combinations of multiple images regardless of image source, e.g. displaying a reference anatomical image with a live image geometric transforms for image registration G06T3/14; enhancement using image fusion G06T5/50; algorithms for registration of images G06T7/30

Abstract

Methods, devices and systems for location of the disposition of a medical probe in a subject are disclosed. An array of electromagnetic drive coil sets, each set having two or three dimensionally oriented drive coils, a sensor coil being electromagnetically communicative with the array of electromagnetic drive coil sets, a discrete core wire providing response to electrical stimuli of the subject, and a system controller communicative with and adapted to energize one or more of the electromagnetic coils in the array of electromagnetic drive coil sets are disclosed. The energizing of the one or more of the electromagnetic coils including one or more of energizing the coils singly, or in pairs of x-y and y-z or x-z coils while measuring the response of the sensor coil, whereby the system uses the measurements of the responses of the sensor coil to calculate the location of the sensor coil relative to said drive coil sets.

Claims

1. A medical device locating system for determining disposition of a sensor coil in a subject, the system comprising:

an array of three or more triplet or quadruplet drive coil sets, each drive coil set including at least three discrete electromagnetic coils;

an elongate flexible probe comprising;

a magnetically permeable, conductive core wire having a proximal end and a distal end, and

at least one sensor coil disposed toward the distal end of the core wire, said sensor coil configured to provide one or more sensor coil response signals;

a first system component configured to provide drive signals energizing the discrete electromagnetic coils by;

sequentially driving one or more of said discrete electromagnetic coils within a drive coil set and selectively providing phase inversion of the drive signal to any one, two, three or more of the discrete electromagnetic coils within the drive coil set, or

simultaneously energizing one, a pair, a triplet or a quadruplet of said discrete electromagnetic coils within a drive coil set;

a second system component configured to measure resulting one or more sensor coil response signals; and

a processor configured to determine the sensor coil disposition relative to the array of three or more triplet or quadruplet drive coil sets based on the measured resulting sensor coil response signals.

2. The system of claim 1, wherein the core wire provides an electrical pathway configured to measure an ECG signal.

3. The system of claim 2, further comprising two additional surface ECG leads placed on the subject.

4. The system of claim 1, wherein the core wire has a shape selected from the group consisting of a circle, an ellipse, a square, a pentagon, a hexagon and an octagon.

5. The system of claim 1, wherein the core wire comprises a material selected from the group consisting of metglas, iron, nanoperm, mu-metal, cobalt-iron, permalloy, ferrous stainless steel and ferrite.

6. The system of claim 1, wherein the sensor coil provides a measurable response to an electromagnetic field when the sensor coil is positioned within 36 inches from the centroid of the array of three or more triplet or quadruplet drive coil sets.

7. The system of claim 1, further comprising a display that displays the disposition of the sensor coil in the subject relative to the array of the triplet or quadruplet drive coil sets.

8. The system of claim 7, wherein the display simultaneously displays the P-wave and the QRS complex of the subject over time with the disposition of the sensor coil.

9. The system of claim 7, wherein said display displays the disposition of the sensor coil in the subject by indicating a height, width or depth of the sensor coil in said subject relative to the array of the triplet or quadruplet drive coil sets.

10. The system of claim 7, wherein said display displays the disposition of the sensor coil in the subject by indicating an angular orientation of the sensor coil in said subject relative to the array of the triplet or quadruplet drive coil sets.

11. The system of claim 1, wherein the second system component is configured to measure resulting one or more sensor coil response signals by selectively amplifying or filtering the one or more sensor coil response signals to produce one or more optimized sensor coil response signals.

12. The system of claim 11, wherein the processor is configured to determine the sensor coil disposition relative to the array of three or more triplet or quadruplet drive coil sets by:

selecting optimum sensor coil response signals from the optimized sensor coil response signals; and

calculating an intersection of spheres using said optimum sensor coil response signals.

13. The system of claim 1, further comprising an automatic gain control circuit within the second system component, the automatic gain control circuit receiving the one or more sensor coil response signals from the sensor coil and maximizing the sensor coil response signals before communicating the sensor coil response signals to the second system component.

14. The system of claim 1, wherein the array is of quadruplet drive coil sets provided as virtual pairs, virtual triplets or virtual quadruplets, and wherein:

the first system component is configured to provide AC drive signals by sequentially sweeping virtual electromagnetic drive vectors from 0 to 90 degrees and −

90 to 0 degrees for x, y, z′ and

z″

axes of the quadruplet drive coil sets;

the processor is further configured to;

determine angle values of maximum and minimum sensor coil responses within a plane using paired coil programmable current drive sweeping a range from 0 to 90 degrees;

determine the angle values of maximum and minimum sensor coil responses within a plane using paired coil programmable current drive sweeping using inverted phases of at least one coil and sweeping a range from −

90 to 0 degrees;

determine at least one set of optimal virtual drive x and y axes for at least two of the quadruplet drive coils as values corresponding to plus and minus 45 degrees from the maximum or minimum sensor coil responses; and

determine an optimal virtual drive orthogonal to the plane of the optimal virtual drive axes to provide at least one optimal virtual triplet drive axes and at least one of the triplet drive coils.

15. The system of claim 1, further comprising an x-axis tilt meter and y-axis tilt meter which use gravity to measure the x-axis and y-axis tilt from true vertical.

16. A method for determining disposition of a sensor probe in a subject, the method comprising:

driving an array of three or more triplet or quadruplet drive coil sets, each drive coil set including at least three discrete electromagnetic coils driven by drive signals to generate respective electromagnetic wave fields;

receiving one or more discrete sensor probe response signals from a moveable sensor probe, the sensor probe including a discrete magnetically permeable conductive core wire and a discrete sensor coil, the magnetically permeable conductive core wire configured to generate a first response signal in response to electrical stimuli of the subject and the sensor coil configured to generate one or more second response signals responsive to the respective electromagnetic wave fields;

measuring the first response signals from the magnetically permeable conductive core wire and the second response signals from the discrete sensor coil;

providing modified drive signals to one or more electromagnetic coils to maximize or optimize one or both;

the generated electromagnetic wave fields, and

the one or more sensor coil response signals;

measuring first modified response signals from the magnetically permeable conductive core wire and second modified response signals from the discrete sensor coil; and

determining sensor probe disposition in the subject relative to the array of three or more triplet or quadruplet drive coil sets based on the measured modified sensor coil response signals.

17. The method of claim 16, wherein measuring the first response signals from the magnetically permeable conductive core wire comprises receiving an electrical signal through the magnetically permeable conductive core wire providing one lead signal enabling the successive measurements for an ECG of said subject.

18. The method of claim 16, wherein measuring the second response signals from the discrete sensor coil comprises normalizing the amplitude of the second response signals from the discrete sensor coil.

19. The method of claim 16, wherein measuring the second modified response signals from the discrete sensor coil comprises normalizing the amplitude of the second modified response signals from the discrete sensor coil.

20. The method of claim 16, further comprising measuring an ECG signal from two additional surface ECG leads placed on the subject.