Catheterscope 3D guidance and interface system

• US 20050182295A1
• Filed: 12/10/2004
• Published: 08/18/2005
• Est. Priority Date: 12/12/2003
• Status: Active Grant

• Current Assignee: University of Washington
• Original Assignee: University of Washington
• Inventors: Seibel, Eric J., Glenny, Robb W., Soper, Timothy D.
• Granted Patent: US 7,901,348 B2
• Time in Patent Office: Days
• US Class Current: 600/117
• CPC Class Codes: A61B 1/000096 using artificial intelligence
• CPC Class Codes: A61B 1/00016 using wireless means
• CPC Class Codes: A61B 1/00045 Display arrangement
• CPC Class Codes: A61B 1/00097 Sensors
• CPC Class Codes: A61B 1/00172 with means for scanning
• CPC Class Codes: A61B 1/005 Flexible endoscopes
• CPC Class Codes: A61B 1/07 using light-conductive means, e.g. optical fibres
• CPC Class Codes: A61B 1/2676 Bronchoscopes
• CPC Class Codes: A61B 2034/2051 Electromagnetic tracking systems
• CPC Class Codes: A61B 2090/3762 using computed tomography systems [CT]
• CPC Class Codes: A61B 34/20 Surgical navigation systems; Devices for tracking or guiding surgical instruments, e.g. for frameless stereotaxis
• CPC Class Codes: A61B 5/06 Devices, other than using radiation, for detecting or locating foreign bodies for removing same A61B17/50 ; determining position of probes within or on the body of the patient
• CPC Class Codes: A61B 5/062 using magnetic field
• CPC Class Codes: A61B 5/065 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 5/066 Superposing sensor position on an image of the patient, e.g. obtained by ultrasound or x-ray imaging
• CPC Class Codes: A61B 5/08 Detecting, measuring or recording devices for evaluating the respiratory organs A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/0816 Measuring devices for examining respiratory frequency measuring frequency of electric signals G01R23/00
• CPC Class Codes: A61B 5/7285 for synchronising or triggering a physiological measurement or image acquisition with a physiological event or waveform, e.g. an ECG signal A61B6/5205, A61B6/541, A61B8/5207, A61B8/543 take precedence
• CPC Class Codes: A61B 6/541 involving acquisition triggered by a physiological signal

Abstract

Visual-assisted guidance of an ultra-thin flexible endoscope to a predetermined region of interest within a lung during a bronchoscopy procedure. The region may be an opacity-identified by non-invasive imaging methods, such as high-resolution computed tomography (HRCT) or as a malignant lung mass that was diagnosed in a previous examination. An embedded position sensor on the flexible endoscope indicates the position of the distal tip of the probe in a Cartesian coordinate system during the procedure. A visual display is continually updated, showing the present position and orientation of the marker in a 3-D graphical airway model generated from image reconstruction. The visual display also includes windows depicting a virtual fly-through perspective and real-time video images acquired at the head of the endoscope, which can be stored as data, with an audio or textual account.

Claims

1. A system for visually guiding a flexible endoscope through linked passages within a body, comprising:

(a) a signal source that emits a reference signal useful for spatially tracking a progress of the flexible endoscope through the linked passages;

(b) a sensor that produces an output signal indicating a three-dimensional disposition of a distal end of the flexible endoscope using the reference signal of the signal source; and

(c) a display for displaying a view from within the linked passages as the flexible endoscope is advanced therethrough, to enable the flexible endoscope to be visually guided and tracked along a path followed through the linked passages.

2. The system of claim 1, further comprising a three-dimensional model of the linked passages, said three-dimensional model being used to assist in determining at least an initial path along which to advance the flexible endoscope through the linked passages.

3. The system of claim 1, wherein the three-dimensional model is derived from an image of a portion of a body in which the linked passages are disposed, the model providing an indication of an orientation and a disposition of the linked passages relative to a specific anatomical feature.

4. The system of claim 1, wherein the signal source comprises an electromagnetic field source, and wherein the signal source and sensor together comprise at least five coils configured to sense at least a three-dimensional position of a distal portion of the flexible endoscope relative to the electromagnetic field source.

5. The system of claim 4, wherein the sensor comprises at least one coil configured to sense both a three-dimensional position and an orientation of the distal portion of the flexible endoscope.

6. The system of claim 2, further comprising a body function sensor configured to be disposed adjacent to one of a sternum, a thorax, and a mouth of a patient, to monitor at least one of breathing, a chest orientation, and a deformation of airways of a patient, for at least one of updating the three-dimensional model in regard to changes caused by at least one body function, and gating a determination of a disposition of the distal end of the flexible endoscope in regard to the at least one body function.

7. The system of claim 1, wherein the flexible endoscope includes a vibrating optical fiber that scans a region adjacent to the distal end of the flexible endoscope, producing a signal that is used to drive the display.

8. A flexible endoscope capable of being visually guided through linked passages within a body, comprising:

(a) a light source;

(b) an optical fiber having a cantilevered portion disposed adjacent to a distal end of the flexible endoscope;

(c) an actuator that is energized to drive the optical fiber to move in a desired pattern to scan a region adjacent to the distal end of the flexible endoscope by emitting light from the cantilevered portion that was conveyed from the light source through the optical fiber;

(d) a light sensor that senses light reflected from the region, producing a signal that is usable to image the region to enable visual guidance of the flexible endoscope through the linked passages; and

(e) a sensor producing an output signal indicating a disposition of the distal end of the flexible endoscope, the output signal being adapted to couple to a tracking system that responds to the output signal produced by the sensor and produces an indication of the disposition of the distal end of the flexible endoscope within the linked passages, as the flexible endoscope is advanced through the linked passages.

9. The flexible endoscope of claim 8, wherein the reference signal comprises an electromagnetic signal, and wherein the reference signal source and the sensor that receives the reference signal together comprise at least five coils configured to indicate a three-dimensional position of the distal end of the flexible endoscope.

10. The flexible endoscope of claim 9, wherein the sensor that receives the reference signal comprises at least one coil configured to indicate both the three-dimensional position and an orientation of the distal end of the flexible endoscope.

11. The flexible endoscope of claim 8, wherein the light sensor comprises a plurality of light sensing regions disposed proximate to the distal end of the flexible endoscope, the plurality of light sensing regions each having a sensitivity to light of different wavebands.

12. The flexible endoscope of claim 8, further comprising at least one lens for focusing light emitted from the cantilevered portion onto a desired scan region that is proximate to the distal end of the flexible endoscope.

13. The flexible endoscope of claim 8, further comprising a housing disposed around the cantilevered portion to provide protection for it, the housing having a window through which light emitted from the cantilevered portion passes to image the linked passages.

14. The flexible endoscope of claim 8, further comprising one of:

(a) a biopsy needle that is adapted to be selectively inserted into a tissue to take a sample;

(b) micro-forceps for taking a sample of a tissue;

(c) a cytological brush for taking a sample of a tissue; and

(d) a fluid channel for taking a bronchial lavage.

15. The flexible endoscope of claim 8, further comprising a lead coupled to the light sensor for conveying at least one electrical signal from the light sensor to a proximal end of the flexible endoscope, for providing the at least one electrical signal to a display used to assist in visually guiding the flexible endoscope through the linked passages to a desired location by imaging a region in the linked passages.

16. The flexible endoscope of claim 8, further comprising a lead that is connected to the sensor and which is adapted to couple the output signal from the sensor to a tracking system.

17. The flexible endoscope of claim 8, further comprising at least one multimode optical fiber to convey light between the distal end and the proximal end of the flexible endoscope.

18. A method for guiding a flexible endoscope through linked passages to either perform a diagnostic procedure or reach a desired location in a patient'"'"'s body, while tracking the disposition of a distal end of the flexible endoscope, comprising the steps of:

(a) using the flexible endoscope for imaging a region of the linked passages that is adjacent to the distal end of the flexible endoscope, to display an image of the region;

(b) providing an external tracking signal that serves as a reference relative to the linked passages within the patient'"'"'s body;

(c) tracking a disposition of the distal end of the flexible endoscope as it is advanced through the linked passages, using an output signal produced in response to sensing the external tracking signal adjacent to the distal end of the flexible endoscope; and

(d) advancing the distal end of the flexible endoscope through the linked passages along a path determined at least in part by the image of the region and the output signal, to reach the desired location in the patient'"'"'s body.

19. The method of claim 18, wherein the step of providing the external tracking signal comprises the step of transmitting an electromagnetic signal that penetrates the patient'"'"'s body, the electromagnetic signal providing a three-dimensional reference for determining the position of the distal end of the flexible endoscope relative to the linked passages, as indicated by the output signal.

20. The method of claim 19, wherein the step of tracking further comprises the step of determining a position of the distal end of the flexible endoscope relative to the linked passages using the three-dimensional reference provided by the electromagnetic signal.

21. The method of claim 18, further comprising the step of providing a three-dimensional model of the linked passages for use in tracking the disposition of the distal end of the flexible endoscope.

22. The method of claim 21, wherein the step of providing the three-dimensional model comprises the steps of:

(a) non-invasively imaging the patient'"'"'s body where the linked passages are disposed; and

(b) producing the three-dimensional model from the image of linked passages within the patient'"'"'s body.

23. The method of claim 21, wherein the step of advancing comprises the steps of:

(a) establishing an arbitrary reference point relative to the three-dimensional model for use in determining the path through the linked passages;

(b) with regard to the arbitrary reference point, establishing three-dimensional model frame coordinates for bifurcations in the linked passages and the desired location; and

(c) determining at least a portion of the path through the linked passages to the desired location, by reference to the three-dimensional model frame coordinates and by visually detecting each bifurcation as the distal end of the flexible endoscope is advanced through the linked passages.

24. The method of claim 23, wherein the step of advancing further comprises the step of establishing at least one calibration point relative to the three-dimensional model based on an anatomical feature within the patient'"'"'s body.

25. The method of claim 24, further comprising the step of scanning the anatomical feature with the flexible endoscope.

26. The method of claim 24, further comprising the step of contacting the anatomical feature with the flexible endoscope.

27. The method of claim 24, further comprising the step of imaging the anatomical feature with the flexible endoscope.

28. The method of claim 24, further comprising the step of imaging the anatomical feature with a calibrated field, using the flexible endoscope.

29. The method of claim 28, further comprising the steps of:

(a) imaging another anatomical feature with another calibrated field, using the flexible endoscope; and

(b) stitching images of the anatomical feature and the other anatomical feature together, using the calibrated fields.

30. The method of claim 28, further comprising the step of painting the optical image onto the three-dimensional model as a texture map.

31. The method of claim 24, providing a calibrated motion correction to the three-dimensional model for motion of the flexible endoscope relative to the three-dimensional model, by producing a time sequence of images of the anatomical feature.

32. The method of claim 23, wherein the step of advancing further comprises the steps of:

(a) displaying a graphic image of the three-dimensional model; and

(b) indicating a position of the distal end of the flexible endoscope on the graphic image, where the position is determined from the output signal.

33. The method of claim 32, wherein the step of advancing further comprises the steps of:

(a) plotting the path of the distal end of the flexible endoscope as a virtual fly-through of the three-dimensional model before advancing the flexible endoscope through the linked passages; and

(b) resolving a direction to take at each bifurcation of the linked passages in the graphic image that is displayed in real-time as the flexible endoscope is advanced through the linked passages, using the model and through direct comparison of the path that was plotted with the position of the distal end of the flexible endoscope indicated on the graphic image.

34. The method of claim 32, wherein the step of advancing further comprises the steps of:

(a) based on the three-dimensional model, determining an angle of deviation of each subtended branch in the linked passages along which the flexible endoscope may be advanced; and

(b) on the graphic image, overlaying a visual marker on a branch that should be followed for the path to reach the desired position, to indicate an appropriate direction of travel at the branch.

35. The method of claim 32, wherein the step of advancing further comprises the steps of:

(a) analyzing the graphic image showing the position of the distal end of the flexible endoscope to segment regions of low intensity associated with passages at a bifurcation, showing two-dimensional deflection angles for each passage; and

(b) at choosing one of the passages through which to advance the flexible endoscope based upon how closely the two-dimensional deflection angles of said one of the passages correlates with a two-dimensional deflection angle of a passage indicated in the three-dimensional model.

36. The method of claim 32, wherein if the path to reach the desired location is beyond a limit of the three-dimensional model, the step of advancing further comprises the steps of:

(a) using the output signal employed for tracking, while beyond the limit of the three-dimensional model, computing a time-average position of the distal end of the flexible endoscope; and

(b) updating the three-dimensional model with a branching tree model, produced from the position of the distal end of the flexible endoscope that was computed and extending from the limit of the three-dimensional model showing each bifurcation and the path along which the flexible endoscope was advanced to produce the branching tree model.

37. The method of claim 32, further comprising the step of painting a surface the three-dimensional model that is displayed, with an image that includes a texture, only at a location of an anatomical feature in the patient'"'"'s body.

38. The method of claim 32, further comprising the steps of:

(a) imaging anatomical features at spaced-apart locations in a patient'"'"'s body; and

(b) painting a surface of the three-dimensional model displayed between the anatomical features, using stitched images that are based on images of the anatomical features.

39. The method of claim 32, further comprising the steps of:

(a) imaging anatomical features in the patients body using a calibrated imaging fields, producing calibrated images; and

(b) stitching the calibrated images together to carry out at least one of the steps of;

(i) offsetting any accumulated error in the three-dimensional model in regard to tracking the distal end of the flexible endoscope; and

(ii) more accurately tracking the distal end of the flexible endoscope when beyond a limit of the three-dimensional model.

40. The method of claim 36, further comprising the steps of:

(a) analyzing subsequent image frames produced by the flexible endoscope to evaluate movement of one of the flexible endoscope and the body of the patient based upon determining differences in successive images; and

(b) refining a position of the distal end of the flexible endoscope based upon the evaluation of the movement.

41. The method of claim 40, further comprising the step of comparing image frames of the linked passages currently produced by the flexible endoscope with previous image frames, for determining the path to follow through the linked passages when advancing the distal end of the flexible endoscope.

42. The method of claim 36, wherein the path followed by the distal end of the flexible endoscope in producing the branching tree model seeks to minimize a distance between the position of the distal end and the desired position, and wherein a predefined threshold for a deviation away from the desired position is applied to determine when to backtrack the flexible endoscope within the linked passages and select a different passage along which to advance the flexible endoscope.

43. The method of claim 36, further comprising the step of only following a path if a current position of the distal end of the flexible endoscope is less than a predefined threshold distance from a desired destination, and if the predefined threshold is exceeded, moving back along the path and taking a different path at a previous branch in the linked passages.

44. The method of claim 36, further comprising the step of displaying a vector indication of a current location and a bearing for the distal end of the flexible endoscope, as feedback to a user who is advancing the flexible endoscope through the linked passages.

45. The method of claim 36, further comprising the step of displaying a delta for each of a plurality of coordinates, and a delta for a total distance, between a current location of the distal end of the flexible endoscope and a desired location in the patient'"'"'s body.

46. The method of claim 18, further comprising the step of taking a tissue sample while the flexible endoscope is within the linked passages.

47. The method of claim 18, further comprising the step of storing data relating to a procedure carried out with the flexible endoscope on the patient.

48. The method of claim 47, wherein the data includes at least one of:

(a) an indication of the path followed by the flexible endoscope, including at least an indication of passages that were entered with the flexible endoscope;

(b) a location in the patient'"'"'s body where a tissue sample was taken with the flexible endoscope;

(c) a comment by a user of the flexible endoscope during the procedure; and

(d) an image of the location where the tissue sample was taken.

49. The method of claim 18, further comprising the step of correcting a current position of the distal end of the flexible endoscope in the linked passages for a movement caused by a physiological activity of the patient'"'"'s body that changes a disposition of a passage in which the distal end of the flexible endoscope is present.

50. The method of claim 18, wherein after the desired location is reached, further comprising the step of enabling a user to selectively record a most efficient path followed by the flexible endoscope through the linked passages to reach the desired location.

51. The method of claim 21, further comprising the steps of:

(a) retracting the flexible endoscope away from a region of interest, through the linked passages;

(b) refining the three-dimensional model based upon the path followed to reach the region of interest; and

(c) assigning the path followed to reach the region of interest to a specific passage within the three-dimensional model.

52. The method of claim 21, wherein after the flexible endoscope has been withdrawn from the patient'"'"'s body, further comprising the step of adjusting the three-dimensional model to match a path followed through the linked passages in reaching at least one region of interest in the patient'"'"'s body.

53. The method of claim 21, further comprising the steps of:

(a) monitoring at least one body function that causes changes in a disposition of the linked passages; and

(b) adjusting the three-dimensional model in regard to data monitored for the at least one body function.

54. The method of claim 53, wherein the step of tracking the disposition of the distal end of the flexible endoscope as it is advanced through the linked passages comprises the step of only enabling tracking function when a state of the at least one body function is substantially identical to that when the three-dimensional model was produced, to minimize an error in tracking the distal end of the flexible endoscope that would otherwise arise due to differences in the state of the at least one body function.

55. The method of claim 21, further comprising the step of enabling a user to selectively rotate the three-dimensional model and images produced by imaging with the flexible endoscope.