ENDOVASCULAR NAVIGATION SYSTEM AND METHOD

• US 20120136242A1
• Filed: 11/08/2011
• Published: 05/31/2012
• Est. Priority Date: 11/08/2010
• Status: Active Grant

• Current Assignee: Teleflex Life Sciences LLC (Teleflex Incorporated)
• Original Assignee: Vasonova, Inc. (Teleflex Incorporated)
• Inventors: QI, Wenkang, HILL, Bradley
• Granted Patent: US 9,119,551 B2
• Time in Patent Office: Days
• US Class Current: 600/424
• CPC Class Codes: A61B 5/026 Measuring blood flow A61B3/1233, A61B3/1241 take precedence
• CPC Class Codes: A61B 5/065 Determining position of the probe employing exclusively positioning means located on or in the probe, e.g. using position sensors arranged on the probe
• CPC Class Codes: A61B 5/283 Invasive
• CPC Class Codes: A61B 5/349 Detecting specific parameters of the electrocardiograph cycle
• CPC Class Codes: A61B 5/389 Electromyography [EMG]
• CPC Class Codes: A61B 5/7264 Classification of physiological signals or data, e.g. using neural networks, statistical classifiers, expert systems or fuzzy systems neural networks per se G06N3/00; expert systems per se G06N5/00
• 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 8/0841 for locating instruments
• CPC Class Codes: A61B 8/12 in body cavities or body tracts, e.g. by using catheters catheters per se A61M25/00
• CPC Class Codes: A61B 8/445 Details of catheter construction
• CPC Class Codes: A61B 8/463 characterised by displaying multiple images or images and diagnostic data on one display composite display in devices for short-range imaging with acoustic waves G01S7/52074
• CPC Class Codes: A61B 8/465 adapted to display user selection data, e.g. icons or menus
• CPC Class Codes: A61B 8/5223 for extracting a diagnostic or physiological parameter from medical diagnostic data for algorithms to analyse biomedical images G06T7/0012
• CPC Class Codes: A61M 2025/0166 Sensors, electrodes or the like for guiding the catheter to a target zone, e.g. image guided or magnetically guided
• CPC Class Codes: A61M 2205/50 with microprocessors or computers
• CPC Class Codes: A61M 2210/12 Blood circulatory system
• CPC Class Codes: A61M 2230/00 Measuring parameters of the user
• CPC Class Codes: A61M 25/01 Introducing, guiding, advancing, emplacing or holding catheters A61M25/10 takes precedence
• CPC Class Codes: A61M 25/0133 Tip steering devices
• CPC Class Codes: G16H 50/30 for calculating health indices; for individual health risk assessment

Abstract

An endovascular navigation and positioning system including a transducer on a distal end of an endovascular instrument, a control system connected to the transducer, the control system being configured to generate and receive at least one acoustic signal using the transducer, a pre-processor containing computer-readable instructions for manipulating the acoustic signal input to extract information related to desired parameters, a processor configured to evaluate the parameters to generate an output related to guidance of the instrument, and an output device for displaying an indication of the output generated by the processor. The processor may evaluate the information using artificial intelligence including inference rules related to navigation state, comparisons to information in a database, and probabilities, among others. The system may use an electrical signal as a confirmation input. Further disclosed is a method of navigating and positioning an endovascular device in a vasculature.

Claims

1. A positioning system, comprising:

a transducer for mounting on a distal end of an endovascular instrument;

a control system connected to the transducer, the control system being configured to generate and receive an acoustic signal using the transducer;

a pre-processor receiving the acoustic signal as an input, the pre-processor containing computer-readable instructions for manipulating the signal input to extract one or more acoustic features from the signal input;

a processor configured to receive the one or more extracted features, the processor containing a computer-readable set of rules to evaluate the extracted features using the rules to generate an output related to guidance of the instrument within a blood vessel or a position of the instrument within the blood vessel; and

an output device for displaying an indication of the output generated by the processor.

2. The positioning system of claim 1, further comprising:

a sensing electrode for mounting on the instrument, the sensing electrode being connected to the control system;

wherein the control system is further configured to receive an electrical signal from the sensing electrode,

and wherein the pre-processor further contains instructions for manipulating the received electrical signal to extract one or more features related to the electrical signal;

and wherein the computer-readable set of rules contains a rule to evaluate the one or more electrical features.

3. The positioning system of claim 1, wherein the acoustic signal comprises a non-imaging ultrasound signal.

4. The positioning system of claim 2, wherein the processor evaluates the one or more electrical features to confirm the output related to the guidance or a position of the instrument within a blood vessel.

5. The positioning system of claim 2, wherein the electrical signal comprises an ECG signal.

6. The positioning system of claim 2, wherein the electrical signal comprises an EMG signal.

7. The positioning system of claim 2, wherein the electrical signal comprises an EEG signal.

8. The positioning system of claim 1, wherein the computer-readable set of rules contained in the processor includes artificial intelligence programming.

9. The positioning system of claim 2, wherein the computer-readable set of rules contained in the processor includes artificial intelligence programming.

10. The positioning system of claim 1, wherein the computer-readable set of rules contained in the processor evaluates the extracted features based on at least one of inference rules, an expert system, a neural network, and logic.

11. The positioning system of claim 2, wherein the computer-readable set of rules contained in the processor evaluates the extracted features based on at least one of inference rules, an expert system, a neural network, and logic.

12. The positioning system of claim 1, the computer-readable set of rules further comprising:

a rule to evaluate whether a power level of the acoustic signal is below a threshold.

13. The positioning system of claim 2, the computer-readable set of rules further comprising:

a rule to evaluate whether a power level of the acoustic signal is below a threshold.

14. The positioning system of claim 1, the computer-readable set of rules further comprising:

a rule to evaluate whether an antegrade flow in the blood vessel is dominant over a retrograde flow in the blood vessel.

15. The positioning system of claim 2, the computer-readable set of rules further comprising:

a rule to evaluate whether an antegrade flow in the blood vessel is dominant over a retrograde flow in the blood vessel.

16. The positioning system of claim 1, the computer-readable set of rules further comprising:

a rule to evaluate whether a retrograde flow in the blood vessel is dominant over an antegrade flow in the blood vessel.

17. The positioning system of claim 2, the computer-readable set of rules further comprising:

a rule to evaluate whether a retrograde flow in the blood vessel is dominant over an antegrade flow in the blood vessel.

18. The positioning system of claim 1, the computer-readable set of rules further comprising:

a rule to evaluate whether a low frequency signal dominates both an antegrade flow in the blood vessel and a retrograde flow in the blood vessel.

19. The positioning system of claim 2, the computer-readable set of rules further comprising:

a rule to evaluate whether a low frequency signal dominates both an antegrade flow in the blood vessel and a retrograde flow in the blood vessel.

20. The positioning system of claim 2, wherein the control system is configured to synchronize the acoustic signal and the electrical signal.

21. The positioning system of claim 2, the computer-readable set of rules further comprising:

a rule to evaluate a P-wave in the received electrical signal relative to a reference.

22. The positioning system of claim 21, the rule to evaluate a P-wave in the received electrical signal relative to a reference further comprising:

providing an output when the P-wave in the received electrical signal is elevated above the reference.

23. The positioning system of claim 21, the rule to evaluate a P-wave in the received electrical signal relative to a reference further comprising:

providing an output when the P-wave in the received electrical signal is at or below the reference.

24. The positioning system of claim 21, the rule to evaluate a P-wave in the received electrical signal relative to a reference further comprising:

providing an output when the P-wave in the received electrical signal is biphasic.

25. The positioning system of claim 1, wherein the output related to the guidance or a position comprises one of a plurality of states, each state related to a predetermined set of conditions of instrument movement or position.

26. The positioning system of claim 1, wherein the output related to the guidance or position comprises an indication of the most probable condition selected from the group consisting of:

instrument moving in a desired direction, instrument moving in an undesired direction, and instrument positioned in a desired location.

27. The positioning system of claim 2, wherein the output related to the guidance or position comprises an indication of the most probable condition selected from the group consisting of:

instrument moving in a desired direction, instrument moving in an undesired direction, and instrument positioned in a desired location.

28. The positioning system of claim 27, wherein the indication of the instrument moving in a desired direction is different from the indication of the instrument positioned in a desired location.

29. The positioning system of claim 2, wherein the one or more features related to the electrical signal corresponds to a pre-selected portion of a regular electrical wave produced by the body.

30. The positioning system of claim 29 wherein the electrical wave is an electrocardiogram and the pre-selected portion is an RS amplitude.

31. The positioning system of claim 29 wherein the electrical wave is an electrocardiogram and the pre-selected portion is an electrocardiogram segment.

32. The positioning system of claim 29 wherein the electrical wave is an electrocardiogram and the pre-selected portion is an electrocardiogram interval.

33. The positioning system of claim 2, wherein the one or more features related to the electrical signal corresponds to a pre-selected portion of an irregular electrical wave produced by the body.

34. The positioning system of claim 33, wherein the one or more features related to the electrical signal correspond to a pre-selected portion of an electrical wave produced by a body having arrhythmia.

35. The positioning system of claim 5, wherein the one or more acoustic features corresponds to a ratio of a retrograde power of the flow in the blood vessel to an antegrade power of the flow in the blood vessel during a single ECG cycle.

36. The positioning system of claim 1, wherein the one or more acoustic features corresponds to a ratio of a low frequency flow power to a high frequency flow power.

37. The positioning system of claim 1, wherein the at least one acoustic feature corresponds to an acoustic signal obtained during a portion of a heart beat.

38. The positioning system of claim 37, wherein the at least one acoustic feature corresponds to the portion of a heart beat during the occurrence of retrograde flow produced by atrial contraction.

39. The positioning system of claim 37, wherein the at least one acoustic feature corresponds to the portion of a heart beat during the occurrence of antegrade flow during systole.

40. The positioning system of claim 39, wherein the at least one acoustic feature corresponds to the portion of a heart beat during the occurrence of retrograde flow at the end of systole.

41. The positioning system of claim 37, wherein the at least one acoustic feature corresponds to the portion of a heart beat during the occurrence of antegrade flow during diastole.

42. The positioning system of claim 2, wherein the one or more features related to the electrical signal corresponds to a portion of an QRS complex.

43. The positioning system of claim 2, wherein the one or more features related to the electrical signal corresponds to a ratio of a magnitude of a P-wave measured by the sensing electrode and a magnitude of a P-wave measured by an external electrode.

44. The positioning system of claim 2, wherein the one or more features related to the electrical signal corresponds to an indication of the presence of a biphasic P-wave.

45. A method of positioning an endovascular instrument in a vasculature comprising:

inserting a system including an endovascular device and at least one transducer into the lumen of a patient;

transmitting an acoustic signal within the lumen;

pre-processing a reflected signal to extract one or more acoustic features; and

processing the one or more acoustic features using a computer readable set of rules to produce an output related to guidance of the instrument within a blood vessel or a position of the instrument within the blood vessel.

46. The method of claim 45, wherein the processing is performed based on a predefined set of inference rules related to one of a set of navigation states.

47. The method of claim 45, wherein the processing is performed based on a predefined set of probabilities related to one of a set of navigation states.

48. The method of claim 45, wherein the processing is performed based on a comparison of the one or more parameters to a predefined set of parameters in a database.

49. The method of claim 45, further comprising displaying the output related to guidance of the device within the blood vessel or a position of the instrument within the blood vessel.

50. The method of claim 49, wherein the output comprises an indication of the most probable condition selected from the group consisting of:

instrument moving in a desired direction, instrument moving in an undesired direction, and instrument positioned in a desired location.

51. The method of claim 50 wherein the desired direction is towards the heart.

52. The method of claim 50 wherein the undesired direction is away from the heart.

53. The method of claim 50 wherein the desired direction is with a flow of blood returning to the heart.

54. The method of claim 50 wherein the undesired direction is against a flow of blood returning to the heart.

55. The method of claim 50 wherein the desired location is within a lower third of the superior vena cava.

56. The method of claim 50 wherein the desired location is proximate to the caval atrial junction.

57. The method of claim 50 wherein the desired location is within the superior vena cava proximate to the caval atrial junction.

58. The method of claim 49, further comprising:

manipulating the device in the blood vessel in response to the output.

59. The method of claim 58 the manipulating step further comprising:

withdrawing the instrument.

60. The method of claim 58 the manipulating step further comprising:

advancing the instrument.

61. A computer readable storage medium having embodied thereon a program, the program being executed by a processor to perform a method for positioning an endovascular instrument in a vasculature, the method comprising:

manipulating a reflected acoustic signal from a sensor on the instrument positioned within a blood vessel to extract one or more acoustic features from the acoustic signal;

manipulating an electrical signal from a lead on the instrument positioned within a blood vessel to extract one or more electrical features from the electrical signal;

generating an output related to guidance or a position of the instrument within the blood vessel using a computer readable set of rules to evaluate the one or more extracted features; and

displaying one of a predetermined number of indications of guidance or position corresponding to the output.

62. The computer readable storage medium of claim 61, wherein the computer readable set of rules to evaluate the one or more extracted features comprises one or more predefined membership functions that indicate one or more positional states of the instrument.

63. The computer readable storage medium of claim 62, further comprising inputting the extracted features into the one or more predefined membership functions and for generating one or more scores that indicate the likelihood of membership in one or more positional states.

64. The computer readable storage medium of claim 63, further comprising weighting the extracted features or one or more membership functions before generating one or more scores.

65. The computer readable storage medium of claim 64, wherein weighting the extracted features or one or more membership functions comprises applying weighting factors to the extracted features or one or more membership functions, wherein the weighting factors apply less weight to an extracted feature or one more membership function based on a weak acoustic or electrical signal, wherein the weighting factors apply more weight to an extracted feature or one more membership function based on a strong acoustic or electrical signal.

66. The computer readable storage medium of claim 64, further comprising selecting the highest score and determining the positional state based on the highest score.

67. The computer readable storage medium of claim 64 wherein one score of the one or more scores relates extracted acoustic features to the direction of movement of the instrument relative to flow in the vasculature.

68. The computer readable storage medium of claim 64 wherein one score of the one or more scores relates acoustic features to the overall flow energy in the vasculature measured by the sensor.

69. The computer readable storage medium of claim 64 wherein one score of the one or more scores relates acoustic features to the overall flow velocity in the vasculature measured by the sensor.

70. The computer readable storage medium of claim 61, wherein the one or more acoustic features corresponds to a ratio of a low frequency flow power to a high frequency flow power.

71. The computer readable storage medium of claim 61, wherein the at least one acoustic feature corresponds to an acoustic signal obtained during a portion of a heart beat.

72. The computer readable storage medium of claim 71, wherein the at least one acoustic feature corresponds to the portion of a heart beat during the occurrence of retrograde flow produced by atrial contraction.

73. The computer readable storage medium of claim 71, wherein the at least one acoustic feature corresponds to the portion of a heart beat during the occurrence of retrograde flow at the end of systole.

74. The computer readable storage medium of claim 71, wherein the at least one acoustic feature corresponds to the portion of a heart beat during the occurrence of antegrade flow during diastole.

75. The computer readable storage medium of claim 61, wherein the one or more electrical features corresponds to a portion of an QRS complex.

76. The computer readable storage medium of claim 61, wherein the one or more electrical features corresponds to a ratio of a magnitude of a P-wave measured by the sensing electrode and a magnitude of a P-wave measured by an external electrode.

77. The computer readable storage medium of claim 61, wherein the one or more electrical features corresponds to an indication of the presence of a biphasic P-wave.

78. A method of determining a position of a medical device in the vasculature of a patient, comprising:

transmitting a signal in the vasculature comprising an ultrasound signal from a distal end of a device;

receiving a reflected ultrasound signal;

extracting an ultrasound feature from the reflected ultrasound signal;

receiving an electrical signal from a lead on the device;

extracting an ECG feature from the received electrical signal;

calculating a plurality of indicator scores using the extracted features; and

identifying a positional state by comparing the indicator scores.

79. The method of claim 78, wherein each feature infers a distinct position in the vasculature.

80. The method of claim 78, the calculating step further comprising:

inputting the extracted features into a plurality of indicator equations representing positioning probabilities.

81. The method of claim 80, wherein the indicator equations correspond to membership functions.

82. The method of claim 80, the indicator equations further comprising:

applying a weighting factor related to the extracted feature used in the indicator equation.

83. The method of claim 78, the identifying step further comprising:

selecting the positional state that corresponds to the highest indicator score.

84. The method of claim 78 the calculating step further comprising:

solving preset equations based on a correlation between an extracted feature and a probability of a particular position or state of navigation of the device.

85. The method of claim 78 wherein one indicator score in the plurality of indicator scores relates extracted acoustic features to the direction of movement of the device relative to flow in the vasculature.

86. The method of claim 78 wherein one indicator score in the plurality of indicator scores relates acoustic features to the overall flow energy in the vasculature measured by the sensor.

87. The method of claim 78 wherein one indicator score in the plurality of indicator scores relates acoustic features to the overall flow velocity in the vasculature measured by the sensor.