Method of determining body exit of an ingested capsule

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.