Field gradient-based remote imaging

Patent metadata

Field	Value
Publication number	US-11583202-B2
Application number	US-201816638773-A
Country	US
Kind code	B2
Filing date	Aug 16, 2018
Priority date	Aug 17, 2017
Publication date	Feb 21, 2023
Grant date	Feb 21, 2023

Abstract

Systems and method for remote field measurement-based mapping of anatomical structures (e.g., using impedance image of electrical fields) are described. In some embodiments, an image of features within a target region is produced by analysis of a spatial pattern of field measurements made in a measurement region remote from the target region features; for example, but not exclusively, by treating the spatial arrangement of field measurements in some portion of the measurement region as indicating the spatial (e.g., angular and/or distance) arrangement of features (e.g., anatomical structure of topography and/or tissue type) in the target region.

First claim

What is claimed is:

1. A method of producing an image using measurements of at least one electrical field made within a first region of a body, the method comprising:
for each of the at least one electrical fields:
receiving a plurality of measurements of voltages of the electrical field measured using an intrabody probe at different positions within the first region, and
mapping voltage gradients of the electrical field to the first region, using the voltage measurements;
analyzing the mapped voltage gradients to identify distortions in the at least one electrical field;
determining positions of apertures in a tissue wall located outside of the first region using the identified distortions as indications of the presence of the apertures at said positions; and
producing an image showing the tissue wall and the apertures.

2. The method of claim 1 , wherein the received measurements were obtained using a plurality of electrodes positioned at known distances along the intrabody probe, and the voltage gradients indicated by the voltage measurements are determined based on the voltage measurements and the known distances.

3. The method of claim 1 , wherein the voltage gradients comprise a plurality of different local voltage gradients within the first region.

4. The method of claim 1 , wherein the producing an image uses voltage gradients from near a periphery of the first region, the near periphery being defined to exclude voltage gradients from a central portion of the first region.

5. The method of claim 4 , wherein the determining positions of the apertures comprises setting distances from the first region to portions of the tissue wall surrounding the apertures as a function of gradient strength near the periphery of the first region.

6. The method of claim 5 , wherein the producing the image comprises setting distances from the first region to features of the image based on a map of voltage gradient strength near the periphery as a function of solid angle.

7. The method of claim 4 , wherein the producing the image comprises setting distances from the first region to features of the image as a function of a decay of a distortion in voltage gradients with distance.

8. The method of claim 1 , comprising producing a plurality of images corresponding to a corresponding plurality of different heartbeat phases, based on a heartbeat phase during which the voltage measurements were measured.

9. The method of claim 1 , comprising: receiving contact measurements, measured while the probe contacts the tissue wall; and identifying a feature of the image which indicates an anatomical structure located behind the tissue wall, based on a mismatch between the position of the surface as measured by the contact measurements and a position of same surface as indicated in the image.

10. The method of claim 1 , wherein the image is produced within about 5 seconds of receiving the first measurements.

11. The method of claim 1 , wherein said producing an image showing the tissue wall and the apertures comprises producing a plurality of portions of an image of the tissue wall, each corresponding to a respective portion of the first region, wherein each portion of the plurality of portions of the image of the tissue wall has in common with the respective portion of the first region an angular position with respect to a reference location.

12. The method of claim 11 , wherein each of the plurality of portions of the first region is between the reference location and the respective imaged portion of the tissue wall.

13. The method of claim 1 , wherein a plurality of respective portions of the first region and of the image are in correspondence, such that the image portions are each respectively indicated by measurements from the respective corresponding portion of the first region.

14. The method of claim 1 , wherein the tissue wall comprises a lumenal wall of a body cavity.

15. The method of claim 14 , wherein the lumenal wall is a wall of a cardiovascular lumen.

16. The method of claim 15 , wherein the cardiovascular lumen comprises a left atrium.

17. The method of claim 14 , wherein the first region comprises a region within the body cavity and at a distance from the lumenal wall of at least 1 cm.

18. The method of claim 1 , comprising determining the positions of structural features of the tissue wall comprising relatively raised and/or recessed features; and wherein the produced image also shows said structural features.

19. The method of claim 1 , wherein the features shown by the image comprise features of the topography of the tissue wall.

20. The method of claim 1 , wherein the tissue wall surrounding the apertures is at a distance from the first region of at least 1 cm.

21. The method of claim 1 , wherein the mapping produces a map of the voltage gradients of the electrical field, and the image is generated using the map.

22. The method of claim 1 , wherein the one or more electrical field comprises at least three electrical fields crossing within the first region.

23. The method of claim 1 , wherein each of the different positions of the probe within the first region is away from a first one of the apertures, said first aperture having a first side facing the first region and second side facing away from the first region, the different positions being on the first side of the first aperture, and the produced image shows a region on the second side of the first aperture.

24. The method of claim 1 , wherein the received measurements were obtained using a plurality of electrodes positioned at known distances along the intrabody probe, and the electrical field gradients indicated by the voltage measurements are determined based on the electrical field data and the known distances.

25. The method of claim 1 , wherein the voltage gradients comprise a plurality of different local voltage gradients, each at a different one of the different positions.

26. The method of claim 23 , wherein the producing the image comprises setting distances from the first region to the first aperture as a function of a decay of a distortion in voltage gradients with distance.

27. The method of claim 1 , wherein the different positions of the probe and portions of the image are in respective correspondence, such that each image portion respectively corresponds to a respective position.

28. The method of claim 1 , wherein the tissue wall is a wall of a cardiovascular lumen.

29. The method of claim 28 , wherein the cardiovascular lumen comprises a left atrium.

30. The method of claim 29 , wherein at least one of the apertures is an ostium of a pulmonary vein.

31. The method of claim 29 , wherein at least one of the apertures is the mitral valve.

32. The method of claim 1 , wherein said measurements comprise voltage measurements made at one or more frequencies within said first region.

Assignees

• Navix Int Ltd

Inventors

• Ben-Haim Shlomo

Classifications

• A61B5/0536 Primary

  Impedance imaging, e.g. by tomography · CPC title

• A61B5/063

  using impedance measurements · CPC title

• A61B5/4233

  oesophagus · CPC title

• A61B5/283

  Invasive · CPC title

• A61B5/6852

  Catheters · CPC title