Using radiofrequency (RF) transmission system to find opening in tissue wall
A method includes receiving, from a probe that includes electrodes and is positioned inside a cavity in an organ of a patient, (i) proximity signals indicative of proximity of the electrodes to a wall of the cavity, and (ii) position signals indicative of positions of the electrodes within the cavity. Based on the proximity signals and the position signals, at least a portion of a volume of the cavity is represented by a sphere model including multiple spheres. A direction is identified along which one or more spheres are larger than one or more surrounding spheres by at least a given factor. Based on the indicated direction, a location of an opening in the wall of the cavity is estimated and presented to a user.
1. A method, comprising:
receiving, from a probe that comprises electrodes and is positioned inside a cavity in an organ of a patient, (i) proximity signals indicative of proximity of the electrodes to a wall of the cavity, and (ii) position signals indicative of positions of the electrodes within the cavity;
based on the proximity signals and the position signals, representing at least a portion of a volume of the cavity by a sphere model comprising multiple spheres having a position and an unscaled radius;
calibrating the unscaled radius of the spheres to absolute values of radius by determining physical contact with cavity wall tissue;
Identifying a direction along which one or more spheres are larger than one or more surrounding spheres by at least a given factor;
based on the indicated direction, estimating a location of an opening in the wall of the cavity; and
presenting the location of the opening to a user.
2. The method according to claim 1 , wherein identifying the direction comprises constructing, based on the sphere model, a surface corresponding to the wall, and identifying that radii of one or more spheres along the surface are larger than the radii of neighboring spheres by at least the given factor.
3. The method according to claim 1 , and comprising storing the estimated location of the opening in a memory.
4. The method according to claim 1 , wherein presenting the location comprises displaying the location of the opening to the user, overlaid on an anatomical map of the portion of the wall.
5. A system, comprising:
an interface, configured to receive, from a probe that comprises electrodes and is positioned inside a cavity in an organ of a patient, (i) proximity signals indicative of proximity of the electrodes to a wall of the cavity, and (ii) position signals indicative of positions of the electrodes within the cavity; and
a processor, configured to:
based on the proximity signals and the position signals, represent at least a portion of a volume of the cavity by a sphere model comprising multiple spheres having a position and an unscaled radius;
calibrate the unscaled radius of the spheres to absolute values of radius by determining physical contact with cavity wall tissue;
identify a direction along which one or more spheres are larger than one or more surrounding spheres by at least a given factor;
based on the indicated direction, estimate a location of an opening in the wall of the cavity; and
present the location of the opening to a user.
6. The system according to claim 5 , wherein the processor is configured to construct, based on the sphere model, a surface corresponding to the wall, and to identify the direction by identifying that radii of one or more spheres along the surface are larger than the radii of neighboring spheres by at least the given factor.
7. The system according to claim 5 , wherein the processor is further configured to store the estimated location of the opening in a memory.
8. The system according to claim 5 , wherein the processor is configured to present the location by displaying the location of the opening to the user, overlaid on an anatomical map of the portion of the wall.