DEVICE, SYSTEM AND METHOD FOR MEASURING CROSS-SECTIONAL AREAS IN LUMINAL ORGANS

• US 20080194996A1
• Filed: 04/04/2008
• Published: 08/14/2008
• Est. Priority Date: 02/21/2003
• Status: Active Grant

• Current Assignee: 3DT Holdings LLC
• Original Assignee: DTherapeutics LLC
• Inventors: Kassab, Ghassan S.
• Granted Patent: US 8,078,274 B2
• Time in Patent Office: Days
• US Class Current: 600/593
• CPC Class Codes: A61B 2017/00026 Conductivity or impedance, e.g. of tissue
• CPC Class Codes: A61B 5/02007 Evaluating blood vessel condition, e.g. elasticity, compliance
• CPC Class Codes: A61B 5/026 Measuring blood flow A61B3/1233, A61B3/1241 take precedence
• 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 5/1076 for measuring dimensions inside body cavities, e.g. using catheters A61B3/1005 takes precedence
• CPC Class Codes: A61B 5/6853 with a balloon
• CPC Class Codes: A61F 2/958 Inflatable balloons for placing stents or stent-grafts
• CPC Class Codes: A61M 2025/109 having balloons for removing solid matters, e.g. by grasping or scraping plaque, thrombus or other matters that obstruct the flow
• CPC Class Codes: A61M 25/10 Balloon catheters A61M25/0125 takes precedence; embolectomy A61B17/22032; retractors A61B17/02; inflatable balloons for placing stents or stent-grafts A61F2/958 ; stomach balloons for treatment of obesity A61F5/0003; oesophagal tubes A61J15/00
• CPC Class Codes: A61M 25/104 used for angioplasty

Abstract

The disclosure of the present application provides for a system for measuring cross-sectional areas and pressure gradients in luminal organs. The disclosure of the present application also provides a method and apparatus for measuring cross-sectional areas and pressure gradients in luminal organs, such as, for example, blood vessels, heart valves, and other visceral hollow organs. In at least one embodiment, a method for measuring a cross-sectional area of a targeted treatment site comprises the steps of introducing a device, injecting two solutions, measuring a first conductance, moving the device, injecting two solutions, measuring a second conductance, and calculating cross-sectional areas based upon the two conductance measurements.

Claims

1. A method for measuring a cross-sectional area of a targeted treatment site, the method comprising the steps of:

introducing a device into a treatment site;

injecting a known volume of a first solution having a first concentration and a first conductivity and injecting a known volume of a second solution having a second concentration and a second conductivity at a first position of the treatment site;

measuring a first treatment site conductance at the first position of the treatment site;

moving the device to a second position of the treatment site at a first speed;

injecting a known volume of a first solution having a first concentration and a first conductivity and injecting a known volume of a second solution having a second concentration and a second conductivity at the second position of the treatment site;

measuring a second treatment site conductance at the second position of the treatment site; and

calculating cross-sectional areas of the first position and the second position of the treatment site.

2. The method of claim 1, wherein the treatment site comprises a site selected from the group consisting of a body lumen, a body vessel, a biliary tract, and an esophagus.

3. The method of claim 1, wherein the treatment site comprises an esophagus, and wherein the step of injecting a known volume of a first solution having a first concentration and a first conductivity comprises the step of administering said first solution to a patient orally.

4. The method of claim 1, wherein the first solution is NaCl.

5. The method of claim 1, further comprising the step of providing electrical current flow for a period of time to the treatment site through the device.

6. The method of claim 1, wherein the first concentration of the first solution does not equal the second concentration of the second solution.

7. The method of claim 1, wherein the first conductivity of the first solution does not equal the second conductivity of the second solution.

8. The method of claim 1, further comprising the step of calculating a first nodal voltage and a first electrical field based upon the first treatment site conductance value and a first current density.

9. The method of claim 8, further comprising the step of applying finite element analysis to the first nodal voltage and the first electrical field, wherein the step of finite element analysis is performed using a finite element software package.

10. The method of claim 1, wherein the device comprises a catheter.

11. The method of claim 10, wherein the catheter comprises an impedance catheter.

12. The method of claim 10, wherein the catheter comprises a guide catheter.

13. The method of claim 1, wherein the device comprises a wire.

14. The method of claim 13, wherein the wire comprises an impedance wire.

15. The method of claim 13, wherein the wire comprises a wire selected from the group consisting of a guide wire, a pressure wire, and a flow wire.

16. The method of claim 13, wherein the wire comprises a flow wire, and wherein the flow wire is operable to measure a velocity of fluid flow.

17. The method of claim 1, wherein the device comprises an inflatable balloon positioned along a longitudinal axis of the device.

18. The method of claim 17, further comprising the step of inflating the balloon to breakup materials causing stenosis at the treatment site.

19. The method of claim 17, wherein the device further comprises a stent located over the balloon, the stent capable of being distended to a desired size and implanted into the treatment site.

20. The method of claim 19, further comprising the steps of:

distending the stent by inflating the underlying balloon; and

releasing and implanting the stent into the treatment site.

21. The method of claim 20, wherein the balloon is inflated using a fluid, and the method further comprising the steps of:

providing electrical current into the fluid filling the balloon at various degrees of balloon distension;

measuring a conductance of the fluid inside the balloon; and

calculating a cross-sectional area of the balloon lumen.

22. The method of claim 1, further comprising the steps of:

selecting an appropriately-sized stent based on a cross-sectional area of the treatment site; and

implanting the stent into the treatment site.

23. The method of claim 1, wherein the device comprises a pressure transducer.

24. The method of claim 23, further comprising the steps of:

measuring a first pressure gradient from the pressure transducer near the treatment site; and

calculating the cross-sectional area of the treatment site based in part on the first pressure gradient.

25. The method of claim 1, wherein the step of injecting a known volume of a first solution having a first concentration and a first conductivity temporarily substantially displaces blood present at the treatment site.

26. The method of claim 1, wherein the first solution is heated to an internal body temperature of a body surrounding the treatment site prior to injection.

27. The method of claim 1, wherein the first solution and the second solution are heated to a common temperature prior to injection.

28. The method of claim 1, wherein the first volume of the first solution is equal to the second volume of the second solution.

29. The method of claim 1, wherein the step of measuring a first treatment site conductance further comprises the step of measuring a first cross-sectional area, and wherein the step of measuring a second treatment site conductance further comprises the step of measuring a second cross-sectional area.

30. The method of claim 29, further comprising the step of constructing a profile of the treatment site based in part on the measurements of the first cross-sectional area and the second cross-sectional area.

31. The method of claim 1, wherein the step of moving the device comprises pulling back the device to a second position of the treatment site.

32. The method of claim 1, wherein the step of moving the device comprises pushing the device forward to a second position of the treatment site.

33. The method of claim 1, wherein the calculation of the cross-sectional areas of the first position and the second position of the treatment site is based in part upon the first treatment site conductance, the second treatment site conductance, the first conductivity of the first solution, and the second conductivity of the second solution.

34. The method of claim 1, further comprising the step of calculating two Coeff ratios based in part upon the first treatment site conductance, the second treatment site conductance, and the cross-sectional areas of the first position and the second position of the treatment site.

35. The method of claim 1, wherein the step of moving the device to a second position of the treatment site further comprises the steps of:

obtaining one or more additional conductance measurements between the first position and the second position of the treatment site; and

calculating one or more additional cross-sectional areas based upon the one or more additional conductance measurements.

36. The method of claim 35, further comprising the step of determining one or more diameters based in part upon the cross-sectional areas of the first position and the second position of the treatment site and the one or more additional cross-sectional areas based upon the additional conductance measurements.

37. The method of claim 36, further comprising the step of constructing a profile of the treatment site based upon the one or more diameters.

38. The method of claim 35, further comprising the step of calculating total conductance for a distance between the first position and the second position of the treatment site.

39. The method of claim 1, further comprising the step of constructing a profile of the treatment site based upon the cross-sectional areas.

40. The method of claim 1, wherein the step of injecting a known volume of a first solution having a first concentration and a first conductivity comprises injecting the first solution local to the first position of the treatment site.

41. The method of claim 1, wherein the device comprises a stent positioned along a longitudinal axis of the device, the stent capable of being distended to a desired size and implanted into the treatment site.

42. The method of claim 41, further comprising the steps of:

positioning the stent at or near the treatment site;

distending the stent; and

releasing and implanting the stent into the treatment site.

43. The method of claim 1, further comprising the step of introducing a stent at or near the treatment site, the stent having a length, a collapsed diameter, and a distended diameter.

44. The method of claim 43, wherein a stent having a particular length is selected based upon a length of a stenosis.

45. The method of claim 44, wherein the length of the stenosis is determined based upon a profile created in part based upon the cross-sectional areas of the first position and/or the second position of the treatment site.

46. The method of claim 43, wherein a stent having a particular collapsed diameter is selected based upon the cross-sectional areas of the first position and/or the second position of the treatment site.

47. The method of claim 43, wherein a stent having a particular distended diameter is selected based upon the cross-sectional areas of the first position and/or the second position of the treatment site.

48. The method of claim 1, wherein the first treatment site conductance and the second treatment site conductance are retrieved by a data acquisition and processing system operably connected to the device, and wherein the data acquisition and processing system is operable to calculate cross-sectional areas.

49. The method of claim 1, wherein the device comprises at least one suction/infusion port in communication with at least one lumen of the device, whereby said injections of solutions occur via the at least one suction/infusion port.

50. The method of claim 49, wherein the device further comprises at least one solution delivery source operably coupled to the at least one lumen of the device, whereby the first solution and the second solution may be injected from the at least one solution delivery source through the at least one lumen of the device, through the at least one suction/infusion port, and into the treatment site.

51. The method of claim 1, wherein the device comprises at least one excitation electrode and at least one detection electrode.

52. The method of claim 51, wherein the at least one excitation electrode comprises a first excitation impedance lead, and wherein the at least one detection electrode comprises a first detection impedance lead.

53. The method of claim 1, wherein the treatment site has a relative longitudinal axis, and wherein the method further comprises the step of constructing a profile along the relative longitudinal axis of the treatment site based in part on the first and second cross-sectional area measurements.

54. The method of claim 1, wherein the treatment site has a relative longitudinal axis, and wherein the step of moving the device to a second position of the treatment site further comprises the steps of:

obtaining one or more additional conductance measurements between the first position and the second position of the treatment site; and

calculating one or more additional cross-sectional areas based upon the one or more additional conductance measurements.

55. The method of claim 54, further comprising the step of constructing a profile along the relative longitudinal axis of the treatment site based in part on the first and second cross-sectional area measurements and the one or more additional cross-sectional areas.

56. The method of claim 54, further comprising the step of determining one or more diameters based in part upon the cross-sectional areas of the first position and the second position of the treatment site and the one or more additional cross-sectional areas based upon the additional conductance measurements.

57. The method of claim 56, further comprising the step of constructing a profile of the treatment site based upon the one or more diameters.

58. The method of claim 1, wherein the device comprises a sensor for measurement of fluid flow.

59. The method of claim 1, wherein the device is dimensioned so that a first solution can be infused therethrough.

60. The method of claim 48, wherein the data acquisition and processing system is operable to receive conductance data from the device at a first treatment site, and wherein the data acquisition and processing system is further operable to determine the first treatment site conductance based in part from the conductance data.

61. The method of claim 51, wherein the device comprises a catheter having a lumen, a proximal end, and a distal end, and wherein the at least one excitation electrode and the at least one detection electrode are positioned at or near the distal end of the catheter.

62. The method of claim 61, wherein the at least one excitation electrode and the at least one detection electrode have insulated electrical wire connections that run through the lumen and proximal end of the catheter.

63. The method of claim 61, wherein the at least one excitation electrode and the at least one detection electrode have electrical wire connections that are embedded within the catheter such that each wire comprising the electrical wire connections are insulated from the other wires.

64. The method of claim 10, wherein the catheter comprises a lumen extending therethrough, and further comprising a wire positioned through at least a portion of the lumen of the catheter.

65. A method for measuring a cross-sectional area of a targeted treatment site, the method comprising the steps of:

introducing a device into a treatment site;

injecting a known volume of a first solution having a first concentration and a first conductivity and injecting a known volume of a second solution having a second concentration and a second conductivity at a first position of the treatment site;

measuring a first treatment site conductance at the first position of the treatment site;

pulling back the device to a second position of the treatment site at a first speed while injecting a known volume of the second solution, wherein the second position is located proximally relative to the first position;

injecting a known volume of a first solution having a first concentration and a first conductivity at the second position of the treatment site;

measuring a second treatment site conductance at the second position of the treatment site; and

calculating cross-sectional areas of the first position and the second position of the treatment site based in part upon the first treatment site conductance, the second treatment site conductance, the first conductivity of the first solution, and the second conductivity of the second solution.

66. The method of claim 65, further comprising the step of constructing a profile of the treatment site based in part on the measurements of the first cross-sectional area and the second cross-sectional area.

67. The method of claim 65, wherein the device comprises an inflatable balloon along a longitudinal axis of the device.

68. The method of claim 67, further comprising the step of inflating the balloon to breakup any materials causing stenosis at the treatment site.

69. The method of claim 67, wherein the device further comprises a stent located over the balloon, the stent capable of being distended to a desired lumen size and implanted into the treatment site.

70. The method of claim 69, further comprising the steps of:

distending the stent by inflating the underlying balloon; and

releasing and implanting the stent into the treatment site.

71. The method of claim 70, wherein the balloon is inflated using a fluid, and further comprising the steps of:

providing electrical current into the fluid filling the balloon at various degrees of balloon distension;

measuring a conductance of the fluid inside the balloon; and

calculating a cross-sectional area of the balloon lumen.

72. The method of claim 65, further comprising the steps of:

selecting an appropriately-sized stent based on a cross-sectional area of the treatment site; and

implanting the stent into the treatment site.

73. The method of claim 65, wherein the step of pulling back the device to a second position of the treatment site further comprises the step of obtaining one or more additional conductance measurements between the first position and the second position of the treatment site and the step of calculating one or more additional cross-sectional areas based upon the one or more additional conductance measurements.

74. The method of claim 73, further comprising the step of constructing a profile of the treatment site based in part upon the cross-sectional area of the first position and the second position of the treatment site and the one or more additional cross-sectional areas based upon the additional conductance measurements.

75. A method for measuring a cross-sectional area of a targeted treatment site, the method comprising the steps of:

calculating a total conductance based upon individual conductance values taken at a proximal end and a distal end of a segment;

calculating two Coeff ratios based upon the total conductance and the cross-sectional areas of the proximal and the distal end of the segment;

linearly interpolating along a length of pull back of a device for the Coeff so that the proximal and the distal end of the segment have the same Coeffs as calculated herein;

calculating a total conductance for the length of the pull back;

multiplying the total conductance for the length of the pull back by its respective Coeff for at least one point calculated during pull back to obtain a cross-sectional area for the at least one point calculated during pull back; and

determining the diameter for the at least one point calculated during pull back from the cross-sectional area for the at least one point calculated during pull back.

76. The method of claim 75, wherein the step of calculating two Coeff ratios is performed by dividing the two cross-sectional areas by the total conductance.

77. The method of claim 75, wherein the step of determining the diameter for the at least one point is determined by multiplying the cross-sectional area of the at least one point by four, dividing the resulting product by pi, and taking the square root of the resulting quotient.

78. A method for measuring a cross-sectional area of a targeted treatment site, the method comprising the steps of:

introducing a device into a treatment site;

injecting a known volume of a first solution having a first concentration and a first conductivity at a first position of the treatment site;

measuring a first conductance at the first position of the treatment site;

injecting a known volume of a second solution having a second concentration and a second conductivity at a first position of the treatment site;

measuring a second conductance at the first position of the treatment site;

moving the device to a second position of the treatment site at a first speed;

injecting a known volume of a first solution having a first concentration and a first conductivity at the second position of the treatment site;

measuring a third conductance at the second position of the treatment site;

injecting a known volume of a second solution having a second concentration and a second conductivity at the second position of the treatment site;

measuring a fourth conductance at the second position of the treatment site; and

calculating cross-sectional areas of the first position and the second position of the treatment site based in part from the first conductance, the second conductance, the third conductance, and the fourth conductance.

79. A method for constructing a profile of a targeted treatment site, the method comprising the steps of:

introducing a device into a treatment site;

injecting a known volume of a first solution having a first concentration and a first conductivity and injecting a known volume of a second solution having a second concentration and a second conductivity at a first position of the treatment site;

measuring a first treatment site conductance at the first position of the treatment site;

moving the device to a second position of the treatment site at a first speed;

injecting a known volume of a first solution having a first concentration and a first conductivity and injecting a known volume of a second solution having a second concentration and a second conductivity at the second position of the treatment site;

measuring a second treatment site conductance at the second position of the treatment site;

calculating cross-sectional areas of the first position and the second position of the treatment site; and

constructing a profile of the treatment site based upon the cross-sectional areas of the first position and the second position of the treatment site.

80. The method of claim 79, wherein the step of moving the device to a second position of the treatment site further comprises the steps of:

obtaining one or more additional conductance measurements between the first position and the second position of the treatment site; and

calculating one or more additional cross-sectional areas based upon the one or more additional conductance measurements.

81. The method of claim 80, further comprising the step of constructing a profile of the treatment site based upon the cross-sectional areas of the first position and the second position of the treatment site and the one or more additional cross-sectional areas.

82. A method for implanting a stent to a targeted treatment site, the method comprising the steps of:

introducing a device into a treatment site;

injecting a known volume of a first solution having a first concentration and a first conductivity and injecting a known volume of a second solution having a second concentration and a second conductivity at a first position of the treatment site;

measuring a first treatment site conductance at the first position of the treatment site;

moving the device to a second position of the treatment site at a first speed;

injecting a known volume of a first solution having a first concentration and a first conductivity and injecting a known volume of a second solution having a second concentration and a second conductivity at the second position of the treatment site;

measuring a second treatment site conductance at the second position of the treatment site;

calculating cross-sectional areas of the first position and the second position of the treatment site;

selecting an appropriately-sized stent based on a cross-sectional area of the treatment site; and

implanting the stent into the treatment site.