Systems and methods for positioning a catheter

• US 8,478,382 B2
• Filed: 02/11/2009
• Issued: 07/02/2013
• Est. Priority Date: 02/11/2008
• Status: Active Grant

• Current Assignee: C.R. Bard, Inc. (Becton, Dickinson & Co)
• Original Assignee: C.R. Bard, Inc. (Becton, Dickinson & Co)
• Inventors: Burnside, Eddie K., Messerly, Shayne, Golden, Robert N., Lee, Rand W.
• Primary Examiner(s): Le, Long V.
• Assistant Examiner(s): Negarestan, Farshad
• Application Number:
  US12/369,625
• Publication Number:
  US 20090203989A1
• Time in Patent Office: 1,602 Days
• Field of Search: 128/899
• US Class Current: 600/424
• CPC Class Codes: A61B 1/00158 using magnetic field
• 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 5/06 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 5/062 using magnetic field
• CPC Class Codes: A61B 5/6851 Guide wires
• CPC Class Codes: A61B 5/6852 Catheters
• CPC Class Codes: A61B 5/72 Signal processing specially adapted for physiological signals or for diagnostic purposes character recognition, recognising digital ink, document-oriented image-based pattern recognition G06V30/00; recognition or understanding of postal images G06V30/424
• CPC Class Codes: A61B 5/742 using visual displays A61B5/339 takes precedence

Abstract

A method for displaying a position of a medical device, such as a catheter, during insertion of the medical device into a patient is disclosed. In one example embodiment, the method includes obtaining a first set of detected position data relating to a location marker, then determining a possible first position of the location marker. A first confidence level relating to a match between the first set of detected position data and a first set of predicted position data is assigned. A determination is made whether the first confidence level meets or exceeds a first threshold. If the first confidence level meets or exceeds the first threshold, a determination is then made whether the first position of the location marker is within a first detection zone. If the first position of the location marker is within the first detection zone, the first position of the location marker is displayed.

Claims

1. A method of depicting a position of a catheter that is within a patient, the method comprising:

moving a location marker associated with the catheter along a path in a direction from an entry point toward a destination, wherein the location marker produces a magnetic field;

positioning a detector having a first detection zone and a second detection zone such that at least the first detection zone includes a portion of the path, wherein the portion of the path included in the first detection zone is proximal relative to any portion of the path included in the second detection zone;

obtaining, via the detector, first measurements of the magnetic field produced by the location marker;

determining a first confidence level regarding a first position of the location marker based on the first measurements;

displaying an initial representative image of the location marker if the first position is within the first detection zone and the confidence level is above a first threshold value;

obtaining, via the detector, second measurements of the magnetic field produced by the location marker;

determining a second confidence level regarding a second position of the location marker based on the second measurements; and

displaying a subsequent representative image of the location marker if the second position is within one or more of the first and second detection zones and the confidence level is above a second threshold value different than the first threshold value.

2. The method of claim 1, wherein the second threshold value is lower than the first threshold value.

3. The method of claim 1, further comprising withholding the initial representative image of the location marker from being displayed if the first position is within the second detection zone and the first confidence level is above the first threshold value.

4. The method of claim 1, further comprising:

tracking movement of the location marker after having displayed the initial representative image of the location marker; and

discontinuing to track movement of the location marker prior to displaying the subsequent representative image.

5. The method of claim 4, wherein the second threshold value is lower than the first threshold value.

6. A system for depicting a position of a catheter, the system comprising:

a detector configured to obtain first and second measurements of a magnetic field produced by a location marker associated with the catheter, wherein a first detection zone and a second detection zone are defined relative to the detector;

a processor in communication with the detector, wherein the processor is configured to;

receive the first measurements from the detector;

compare the first measurements with a model of the location marker;

provide a first confidence level regarding a first position of the location marker;

receive the second measurements from the detector;

compare the second measurements with the model of the location marker; and

provide a second confidence level regarding a second position of the location marker; and

a display device configured to show an image representative of the location marker, wherein the system is configured to show an initial display of the image only if the first confidence level is above a first threshold value and the first position is within the first detection zone, and wherein the system is configured to show a subsequent display of the image if the second confidence level is above a second threshold value different from the first threshold value and the second position is within one or more of the first and second detection zones.

7. The system of claim 6, wherein the location marker is temporarily or permanently associated with the catheter and includes at least one of the following:

a magnetic component; and

an electromagnetic field-producing component.

8. The system of claim 6, wherein the location marker is a magnetic component included on a stylet that is removably inserted into a lumen of the catheter.

9. A method for displaying a position of a medical device during placement of the medical device into a patient using a system including a processor, the method comprising:

(a) obtaining a first set of detected position data relating to a location marker associated with the medical device;

(b) determining a possible first position of the location marker;

(c) assigning a first confidence level relating to a match between the first set of detected position data and a first set of predicted position data relating to the possible first position;

(d) determining that the first confidence level meets or exceeds a first threshold;

(e) determining that the first position of the location marker is within a first detection zone if the first confidence level meets or exceeds the first threshold;

(f) displaying the first position of the location marker if the first position of the location marker is within the first detection zone;

(g) obtaining a second set of detected position data relating to the location marker;

(h) determining a possible second position of the location marker;

(i) assigning a second confidence level relating to a match between the second set of detected position data and a second set of predicted position data relating to the possible second position;

(j) determining that the second confidence level meets or exceeds a second threshold different from the first threshold;

(k) determining that the second position of the location marker is within at least one of the first detection zone and a second detection zone if the second confidence level meets or exceeds the second threshold; and

(l) displaying the second position of the location marker if the second position of the location marker is within at least one of the first detection zone and the second detection zone.

10. The method of claim 9, wherein stage (b) further comprises:

(b) determining a possible first position of the location marker via a neural net best fit algorithm;

and wherein stage (k) further comprises;

(k) determining that the second position of the location marker is within at least one of the first detection zone and a second detection zone, the first detection zone at stage (i) including dimensions larger than when the first set of detected position data was obtained at stage (a).

11. The method of claim 9, further comprising calibrating the system before executing stage (a).

12. The method of claim 9, wherein stage (k) further comprises:

(k) ensuring that the second position of the location marker is within a predetermined distance range from the first position of the location marker within a predetermined amount of time.

13. The method of claim 9, wherein the location marker includes a magnetic component attached to the medical device, wherein the first position and the second position of the location marker are defined with respect to an X, Y, Z coordinate axis grid including an origin at or proximate to the detector, and wherein a depth of the first detection zone is at least 8 cm.

14. The method of claim 9, wherein at least stages (b) and (c) are repeatedly executed in succession a predetermined number of times before stage (d) is executed.

15. The method of claim 9, wherein a shape of at least one of the first and second detection zones is selected from the list consisting of:

square box, rectangular box, triangular volume, spherical, ellipsoid; and

paraboloid.

16. A computer program product for implementing a method for displaying a position of a medical device during placement of the medical device into a patient, the computer program product including one or more non-transitory computer-readable media having stored thereon computer executable instructions that, when executed by a processor, cause a computer system to perform the following:

(a) obtain a first set of detected position data relating to a location marker associated with the medical device;

(b) determine a possible first position of the location marker;

(c) assign a first confidence level relating to a match between the first set of detected position data and a first set of predicted position data relating to the possible first position;

(d) determine that the first confidence level meets or exceeds a first threshold;

(e) determine that the first position of the location marker is within a first detection zone if the first confidence level meets or exceeds the first threshold;

(f) display the first position of the location marker if the first position of the location marker is within the first detection zone;

(g) obtain a second set of detected position data relating to the location marker;

(h) determine a possible second position of the location marker;

(i) assign a second confidence level relating to a match between the second set of detected position data and a second set of predicted position data relating to the possible second position;

(j) determine that the second confidence level meets or exceeds a second threshold different from the first threshold;

(k) determine that the second position of the location marker is within at least one of the first detection zone and a second detection zone if the second confidence level meets or exceeds the second threshold; and

(l) display the second position of the location marker if the second position of the location marker is within at least one of the first detection zone and the second detection zone.