Method of determining body exit of an ingested capsule

• US 8,696,602 B2
• Filed: 03/30/2010
• Issued: 04/15/2014
• Est. Priority Date: 03/31/2009
• Status: Active Grant

• Current Assignee: Given Imaging Incorporated (Medtronic Plc)
• Original Assignee: Given Imaging Incorporated (Medtronic Plc)
• Inventors: Semler, John R., Selover, Kathleen H., Rohde, Bemina L.
• Primary Examiner(s): Szmal, Brian
• Assistant Examiner(s): Nguyen, Huong Q.
• Application Number:
  US12/798,093
• Publication Number:
  US 20100249645A1
• Time in Patent Office: 1,477 Days
• Field of Search: 600/302, 600/561, 600101-182, 600/582, 600/587
• US Class Current: 600/593
• CPC Class Codes: A61B 1/041 Capsule endoscopes for imaging
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/01 Measuring temperature of body parts ; Diagnostic temperature sensing, e.g. for malignant or inflamed tissue clinical contact thermometers G01K13/20
• CPC Class Codes: A61B 5/036 by means introduced into body tracts A61B5/032 and A61B5/035 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 5/073 Intestinal transmitters
• CPC Class Codes: A61B 5/6861 Capsules, e.g. for swallowing or implanting

Abstract

A method of determining body exit of an ingestible capsule comprising the steps of providing (40) an ingestible capsule (20) having a pressure sensor (23), having (41) a subject ingest the capsule, recording (42a) measurements from the pressure sensor as the capsule passes through at least an end portion of a gastrointestinal tract of the subject, transmitting (44) the measurements to a processor (31) outside of the gastrointestinal tract of the subject, identifying (47) an increasing pressure sequence (65) in the measurements between a selected start time (62) and a transmission end time (63), comparing (48) the sequence to a reference (66), and using the comparison to make a determination (52) regarding the capsule exiting the gastrointestinal tract of the subject. The increasing pressure sequence may be the longest increasing pressure sequence in the measurements. The reference may be a logarithmic regression of the measurements. The ingestible capsule may further comprise a temperature sensor (22) and the method may further comprising the steps of recording (42b) measurements from the temperature sensor as the capsule passes through the end portion of the gastrointestinal tract of the subject, transmitting (43) the measurements to the processor, analyzing (46) the temperature measurements for a substantial drop (68) in the temperature measurements, and using the analysis of the temperature measurements to make the determination regarding the capsule exiting the gastrointestinal tract of the subject.

Claims

1. A method of determining body exit of an ingestible capsule comprising the steps of:

recording measurements from a pressure sensor included in said capsule as said capsule passes through at least an end portion of a gastrointestinal tract of said subject; and

transmitting said measurements to a processor outside of said gastrointestinal tract of said subject, said processor configured to;

identify a sequence of consecutively increasing pressure measurements in said measurements concurrently as the capsule traverses through said end portion of the gastrointestinal tract from a selected start time to a transmission end time;

compare said sequence to a reference; and

determine said capsule exiting said gastrointestinal tract of said subject based on said comparison.

2. The method set forth in claim 1, wherein said increasing pressure sequence is the longest increasing pressure sequence in said measurements.

3. The method set forth in claim 1, wherein said reference is a logarithmic regression of said measurements.

4. The method set forth in claim 1, wherein said ingestible capsule further comprises a temperature sensor.

5. The method set forth in claim 4, and further comprising the steps of:

recording measurements from said temperature sensor as said capsule passes through said end portion of said gastrointestinal tract of said subject; and

transmitting said measurements to said processor, said processor further programmed to;

analyze said temperature measurements for a drop in said temperature measurements; and

determine said capsule exiting said gastrointestinal tract of said subject also based on said analysis of said temperature measurements.

6. The method set forth in claim 1, further comprising the step of conditioning said measurements between said selected start time and said transmission end time to provide terminating pressure data as a function of time, and wherein said increasing pressure sequence is identified in said terminating pressure data.

7. The method set forth in claim 6, wherein said step of conditioning said measurements comprises the steps of:

screening said measurements to verify that they are valid;

converting said measurements to units of pressure; and

scaling said units of pressure such that ambient atmospheric pressure is set at a zero baseline.

8. The method set forth in claim 1, wherein said step of transmitting said measurements to a processor comprises the steps of:

transmitting said measurements from said capsule to a receiver outside of said gastrointestinal tract of said subject; and

downloading said measurements from said receiver to said processor.

9. The method set forth in claim 1, wherein said selected start time is one hour prior to said transmission end time.

10. The method set forth in claim 1, further comprising the step of providing a positive determination regarding said capsule exiting said gastrointestinal tract of said subject when said comparison indicates a match.

11. The method set forth in claim 10, wherein a standard correlation coefficient of 0.8 or greater indicates that said comparison is a match and a standard correlation coefficient of less than 0.8 indicates that said comparison is not a match.

12. The method set forth in claim 5, further comprising the step of providing a positive determination regarding said capsule exiting said gastrointestinal tract of said subject when said comparison indicates a match or there is said drop in said temperature measurements.

13. The method set forth in claim 5, further comprising the step of providing a negative determination regarding said capsule exiting said gastrointestinal tract when said comparison indicates not a match and there is not said drop in said temperature measurements.

14. The method set forth in claim 1, wherein said ingestible capsule further comprises a power source adapted to provide current to an electrical circuit housed in said capsule.

15. The method set forth in claim 14, and further comprising the steps of:

measuring voltage for said circuit as said capsule passes through said gastrointestinal tract of said subject; and

transmitting said voltage measurements to said processor, said processor further programmed to;

analyze said voltage measurements for a low voltage condition; and

determine said capsule exiting said gastrointestinal tract of said subject based on said analysis of said voltage measurements.

16. The method set forth in claim 15, and further comprising the step of providing a negative determination regarding said capsule exiting said gastrointestinal tract when said low voltage condition is indicated.

17. The method set forth in claim 16, wherein said low voltage condition comprises a voltage measurement of less than 2.5 volts.

18. The method set forth in claim 16, wherein said low voltage condition comprises a series of decreasing voltage measurements over a time period.

19. The method set forth in claim 1, further comprising the step of displaying said determination on a display.

20. A method of determining body exit of an ingestible capsule comprising the steps of:

recording measurements from a pressure sensor and a temperature sensor included in said capsule as said capsule passes through at least an end portion of a gastrointestinal tract of said subject;

measuring voltage for a power source adapted to provide current to an electrical circuit included in said capsule as said capsule passes through said gastrointestinal tract of said subject; and

transmitting said measurements to a processor outside of said gastrointestinal tract of said subject, said processor programmed to perform the steps of;

analyzing said voltage measurements for a low voltage condition;

analyzing said temperature measurements for a drop in said temperature measurements;

identifying a longest consecutive sequence of increasing pressure measurements in said measurements concurrently as the capsule traverses through said end portion of the gastrointestinal tract from a selected start time to a transmission end time to provide terminating pressure data as a function of time;

comparing said sequence to a reference; and

making a determination regarding said capsule exiting said gastrointestinal tract of said subject as a function of said comparison, said analysis of said temperature measurements, and said analysis of said voltage measurements.

21. The method set forth in claim 20, wherein said step of making a determination regarding said capsule exiting said gastrointestinal tract of said subject comprises the steps of:

determining if said comparison is a match;

determining if there is a corresponding drop in said temperature measurements; and

determining if there is a low voltage condition.

22. The method set forth in claim 21, further comprising the step of providing a positive determination regarding said capsule exiting said gastrointestinal tract when said comparison is a match, when there is said corresponding drop in said temperature measurements, and when there is not said low voltage condition.

23. The method set forth in claim 21, further comprising the step of providing a negative determination regarding said capsule exiting said gastrointestinal tract when said comparison is not a match, when there is not said corresponding drop in said temperature measurements, and when there is said low voltage condition.

24. A method of determining body exit of an ingestible capsule comprising the steps of:

recording measurements from a pressure sensor and a temperature sensor included in said capsule as said capsule passes through at least an end portion of a gastrointestinal tract of said subject; and

transmitting said measurements to a processor outside of said gastrointestinal tract of said subject, said processor programmed to perform the steps of;

analyzing said temperature measurements for a decrease in temperature;

providing a terminating data set for said pressure and temperature measurements between said decrease in temperature and a transmission end time;

analyzing said terminating data set to determine a relationship between said pressure and said temperature measurements, wherein said relationship comprises the slope of a linear regression of said terminating data set;

comparing said relationship to a reference; and

determining said capsule exiting said gastrointestinal tract of said subject based on said comparison.

25. The method set forth in claim 24, wherein said reference comprises a thermal coefficient of sensitivity for said pressure sensor in pressure units per units of temperature.

26. The method set forth in claim 25, wherein said step of analyzing said terminating data set comprises the steps of:

organizing said pressure and temperature measurements into data pairs;

performing a linear regression with respect to said data pairs to provide a best fit line; and

determining the slope of said best fit line.

27. The method set forth in claim 26, wherein said step of comparing said relationship to a reference comprises comparing said slope to said thermal coefficient of sensitivity for said pressure sensor.

28. The method set forth in claim 27, further comprising the step of providing a positive determination regarding said capsule exiting said gastrointestinal tract of said subject when said comparison is positive.

29. The method set forth in claim 24, further comprising the step of conditioning said pressure measurements prior to said step of providing a terminating data set for said pressure and temperature measurements between said decrease in temperature and said transmission end time.

30. The method set forth in claim 29, wherein said step of conditioning said pressure measurements comprises the steps of:

screening said pressure measurements to verify that they are valid;

converting said pressure measurements to units of pressure; and

scaling said units of pressure such that ambient atmospheric pressure is set at a zero baseline.

31. The method set forth in claim 24, wherein said step of transmitting said measurements to a processor comprises the steps of:

transmitting said measurements from said capsule to a receiver outside of said gastrointestinal tract of said subject; and

downloading said measurements from said receiver to said processor.

32. The method set forth in claim 24, wherein said selected start time is one hour prior to said transmission end time.

33. The method set forth in claim 24, wherein said ingestible capsule further comprises a power source adapted to provide current to an electrical circuit housed in said capsule.

34. The method set forth in claim 33, further comprising the steps of:

measuring voltage for said circuit as said capsule passes through said gastrointestinal tract of said subject; and

transmitting said voltage measurements to said processor, said processor further programmed to perform the steps of;

analyzing said voltage measurements for a low voltage condition; and

determining said capsule exiting said gastrointestinal tract of said subject based on said analysis of said voltage measurements.

35. The method set forth in claim 34, wherein said low voltage condition comprises a series of decreasing voltage measurements over a time period.

36. The method set forth in claim 24, wherein said processor is further programmed to perform the steps of:

determining a correlation value between temperature and pressure data in said terminating data set; and

determining said capsule exiting said gastrointestinal tract of said subject based on said correlation value.

37. The method set forth in claim 36, wherein said correlation value is an R-squared correlation coefficient for said linear regression.

38. The method set forth in claim 37, wherein a correlation coefficient of 0.9 or greater indicates that said determination is positive and a correlation coefficient of less than 0.9 indicates that said determination is not positive.

39. A method of determining body exit of an ingestible capsule comprising the steps of:

recording measurements from a pressure sensor and a temperature sensor included in said capsule as said capsule passes through at least an end portion of a gastrointestinal tract of said subject; and

transmitting said measurements to a processor outside of said gastrointestinal tract of said subject, said processor programmed to perform the steps of;

analyzing said temperature measurements for a decrease in temperature;

providing a terminating data set for said pressure and temperature measurements between said decrease in temperature and a transmission end time;

determining a correlation value between temperature and pressure data in said terminating data set; and

determining said capsule exiting said gastrointestinal tract of said subject based on said correlation value.

40. The method set forth in claim 39, wherein said step of determining a correlation value between temperature and pressure data in said terminating data set comprises the step of performing a linear regression with respect to said data set.

41. The method set forth in claim 40, wherein said correlation value is an R-squared correlation coefficient for said linear regression.

42. The method set forth in claim 41, wherein a correlation coefficient of 0.9 or greater indicates that said determination is positive and a correlation coefficient of less than 0.9 indicates that said determination is not positive.

43. A non-transitory computer-readable medium having computer-executable instructions for performing a method comprising:

receiving pressure measurements recorded by a pressure sensor on an ingestible capsule ingested by a subject; and

instructing a processor to perform steps comprising;

identifying a sequence of consecutively increasing pressure measurements in said measurements concurrently as the capsule traverses through said end portion of the gastrointestinal tract from a selected start time to a transmission end time;

comparing said sequence to a reference; and

determining said capsule exiting said gastrointestinal tract of said subject based on said comparison.

44. The medium set forth in claim 43, wherein said increasing pressure sequence is the longest increasing pressure sequence in said measurements.

45. The medium set forth in claim 43, wherein said reference is a logarithmic regression of said measurements.

46. The medium set forth in claim 43, and further comprising:

receiving temperature measurements recorded by a temperature sensor on said ingestible capsule; and

instructing said processor to perform further steps comprising;

analyzing said temperature measurements for a drop in said temperature measurements; and

determining said capsule exiting said gastrointestinal tract of said subject based on said analysis of said temperature measurements.

47. The medium set forth in claim 43, and further comprising conditioning said measurements between said selected start time and said transmission end time to provide terminating pressure data as a function of time, and wherein said increasing pressure sequence is identified in said terminating pressure data.

48. The medium set forth in claim 43, wherein said conditioning said measurements comprises:

screening said measurements to verify that they are valid;

converting said measurements to units of pressure; and

scaling said units of pressure such that ambient atmospheric pressure is set at a zero baseline.

49. The medium set forth in claim 43, wherein said selected start time is one hour prior to said transmission end time.

50. The medium set forth in claim 46, and further comprising the steps of

receiving voltage measurements recorded by said ingestible capsule;

and

instructing said processor to perform further steps comprising;

analyzing said voltage measurements for a low voltage condition; and

determining said capsule exiting said gastrointestinal tract of said subject based on said analysis of said voltage measurements.

51. A system for identifying the body exit of an ingestible capsule from a gastrointestinal tract comprising:

an ingestible capsule having a pressure sensor adapted to record pressure data as a function of time as said capsule passes through at least a portion of a subject'"'"'s gastrointestinal tract;

a receiver adapted to received said data when transmitted from said capsule;

a processor adapted to communicate with said receiver;

a display in communication with said processor;

said processor programmed to;

receive pressure measurements recorded by said pressure sensor;

identify a sequence of consecutively increasing pressure measurements in said measurements concurrently as the capsule traverses through said end portion of the gastrointestinal tract from a selected start time to a transmission end time;

compare said sequence to a reference; and

determine said capsule exiting said gastrointestinal tract of said subject based on said comparison.

52. The system set forth in claim 51, wherein said increasing pressure sequence is the longest increasing pressure sequence in said measurements.

53. The system set forth in claim 51, wherein said reference is a logarithmic regression of said measurements.

54. The system set forth in claim 51, wherein:

said ingestible capsule further comprises a temperature sensor adapted to record temperature data as a function of time as said capsule passes through at least a portion of a subject'"'"'s gastrointestinal tract; and

said processor is further programmed to

receive temperature measurements recorded by said temperature sensor;

analyze said temperature measurements for a drop in said temperature measurements; and

determine said capsule exiting said gastrointestinal tract of said subject based on said analysis of said temperature measurements.

55. The system set forth in claim 51, wherein said processor is further programmed to condition said measurements between said selected start time and said transmission end time to provide terminating pressure data as a function of time, and wherein said increasing pressure sequence is identified in said terminating pressure data.

56. The system set forth in claim 55, wherein, for conditioning said measurements, said processor is further configured to:

screen said measurements to verify that they are valid;

convert said measurements to units of pressure; and

scale said units of pressure such that ambient atmospheric pressure is set at a zero baseline.

57. The system set forth in claim 51, wherein said selected start time is one hour prior to said transmission end time.

58. The system set forth in claim 54, wherein said processor is further programmed to:

receive voltage measurements recorded by said ingestible capsule; and

analyze said voltage measurements for a low voltage condition; and

use said analysis of said voltage measurements to make said determination regarding said capsule exiting said gastrointestinal tract of said subject.

59. A non-transitory computer-readable medium having computer-executable instructions for performing a method comprising:

receiving pressure measurements recorded by a pressure sensor and temperature measurements recorded by a temperature sensor on an ingestible capsule ingested by a subject; and

instructing a processor to perform steps comprising;

analyzing said temperature measurements for a decrease in temperature;

providing a terminating data set for said pressure and temperature measurements between said decrease in temperature and a transmission end time;

analyzing said terminating data set to determine a relationship between said pressure and said temperature measurements, where said relationship comprises the slope of a linear regression of said terminating data set;

comparing said relationship to a reference; and

determining said capsule exiting said gastrointestinal tract of said subject based on said comparison.

60. The medium set forth in claim 59, wherein said reference comprises a thermal coefficient of sensitivity for said pressure sensor in pressure units per units of temperature.

61. The medium set forth in claim 59, wherein analyzing said terminating data set comprises:

organizing said pressure and temperature measurements into data pairs;

performing a linear regression with respect to said data pairs to provide a best fit line; and

determining the slope of said best fit line.

62. The medium set forth in claim 61, wherein comparing said relationship to a reference comprises comparing said slope to said thermal coefficient of sensitivity for said pressure sensor.

63. The medium set forth in claim 59 and further comprising:

determining a correlation value between temperature and pressure data in said terminating data set; and

determining said capsule exiting said gastrointestinal tract of said subject based on said correlation value.

64. The medium set forth in claim 63, wherein said correlation value is an R-squared correlation coefficient for said linear regression.

65. The medium set forth in claim 64, wherein a correlation coefficient of 0.9 or greater indicates that said determination is positive and a correlation coefficient of less than 0.9 indicates that said determination is not positive.

66. A non-transitory computer-readable medium having computer-executable instructions for performing a method comprising:

receiving pressure measurements recorded by a pressure sensor and temperature measurements recorded by a temperature sensor on an ingestible capsule ingested by a subject; and

instructing a processor to perform steps comprising;

analyzing said temperature measurements for a decrease in temperature;

providing a terminating data set for said pressure and temperature measurements between said decrease in temperature and a transmission end time;

determining a correlation value between temperature and pressure data in said terminating data set; and

determining, said capsule exiting said gastrointestinal tract of said subject based on said correlation value.

67. The medium set forth in claim 66, wherein determining a correlation value between temperature and pressure data in said terminating data set comprises performing a linear regression with respect to said data set.

68. The medium set forth in claim 67, wherein said correlation value is an R-squared correlation coefficient for said linear regression.

69. The medium set forth in claim 68, wherein a correlation coefficient of 0.9 or greater indicates that said determination is positive and a correlation coefficient of less than 0.9 indicates that said determination is not positive.