Automatic compilation of electroanatomical maps

Abstract

A method for mapping includes calculating an initial three-dimensional (3D) morphology representing the interior surface of a cavity within a living body and receiving physiological data measured at a plurality of points distributed across the interior surface of the cavity. For each region of a plurality of regions of the initial 3D morphology, a respective distance from the region to a nearest point of the plurality of points is calculated, and one or more of the regions whose respective distances are greater than a specified threshold distance are identified. The initial 3D morphology is modified to bring each of the identified regions within the specified threshold distance of at least one point of the plurality of points. A 3D map of the cavity is rendered on a display based on the modified 3D morphology and the measured physiological data.

Description

[Technical Field]

[0001] The present disclosure relates generally to the graphical representation and display of anatomical structures, and more particularly to electroanatomical mapping of organs such as the heart. [Background technology]

[0002] In electroanatomical mapping, the three-dimensional (3D) shape of the surface of a body organ is measured and modeled as a 3D map, and electrical activity at locations along the surface is measured and displayed on the 3D map. For example, the interior shape of a heart chamber can be mapped by inserting a position-sensing catheter into the chamber and inserting a point cloud into a 3D mesh representing the endocardial surface of the chamber. Electrodes on the distal end of the catheter measure electrical potentials at many points on the endocardial surface. These electrical measurements are typically represented as colors applied to corresponding locations on the 3D mesh. Colors between measurement points can be interpolated to visualize electrical activity across the entire 3D surface of the heart chamber.

[0003] U.S. Patent Application Publication No. 2022 / 0225925, the disclosure of which is incorporated herein by reference, describes a method that includes receiving or generating a volumetric map of at least a portion of a cavity of a bodily organ, the volumetric map including a plurality of mapping locations, and a point cloud of locations within the cavity that have been marked for treatment. The volumetric map is updated by removing a portion of the mapping locations so that the locations marked for treatment fall on a surface of the volumetric map. Using the updated volumetric map, a map of at least a portion of the cavity is generated that includes the locations marked for treatment. The map is displayed to a user.

[0004] The present disclosure will be more fully understood from the following detailed description of the embodiments thereof, taken in conjunction with the drawings in which: [Brief explanation of the drawings]

[0005] [Figure 1]1 is a schematic, pictorial illustration of a catheter-based electrophysiology mapping and ablation system, according to an embodiment of the present disclosure; [Figure 2] 1 is a schematic, depiction of an electroanatomical map according to an embodiment of the present disclosure; [Figure 3] 1A-1C are schematic cross-sectional views of an anatomical map illustrating a method for applying electrical data to the map, according to an embodiment of the present disclosure. [Figure 4] 1 is a flow chart that schematically illustrates a method for generating an electroanatomical map according to an embodiment of the present disclosure. [Figure 5] 1A-1C are schematic, depictive illustrations of an electroanatomical map at successive stages of modification of the map surface, according to an embodiment of the present disclosure; [Figure 6] 1A-1C are schematic, depictive illustrations of an electroanatomical map at successive stages of modification of the map surface, according to an embodiment of the present disclosure; DETAILED DESCRIPTION OF THE INVENTION

[0006] overview When an anatomical map of the interior surface of a body cavity, such as the interior surface of a heart chamber, is created using the type of FAM process described above, the surface of the map is often "dilated" relative to the actual anatomical structure of the cavity. In other words, portions of the surface of the 3D map extend beyond the boundaries of the actual anatomical surface. One reason for this type of dilation in maps of heart chambers, for example, is that the positions of the points used in the FAM process are acquired over different periods of the cardiac and respiratory cycles, and the resulting movement of the heart wall causes smearing of the map. Another reason is "tenting," i.e., outward distortion of the interior surface of the cavity due to the pressure of a probe, such as a catheter, used to collect positional data for mapping.

[0007] When the surface of the 3D anatomical map is rendered on a display, physiological data measured within the chamber can be represented on the display. For example, electrophysiological measurements obtained by a catheter at points on the inner surface of a heart chamber can be presented by coloring the 3D map to represent local electrical potential levels or electrical activation times. To display the measurement data, each physiological measurement point is projected onto the nearest region of the map. Regions of the map that do not have nearby physiological measurement points do not display any measurement indicators. For example, when color is used to represent physiological measurements, regions with no nearby measurement points can be colored gray.

[0008] This type of "gray area" can occur not only when there are insufficient measurement points, but also due to local expansion of the 3D anatomical map, which pushes the map surface away from the actual measurement points. As a result, gray areas in the colored electroanatomical map can appear falsely, indicating a lack of electrical activity and misrepresenting the shape of the heart chambers. While cardiologists can recognize and correct these areas by interacting with the computer system used to generate the map, this interactive process is difficult and time-consuming.

[0009] Examples of the present disclosure address these problems by automatically identifying and correcting distortions in 3D anatomical maps. In these examples, a computer identifies regions of the map that are far from the nearest measurement point and "shaves" the map in these regions, i.e., reduces the map's volume in each region, thus moving the map surface closer to the nearest measurement point. This shaving process can be performed iteratively so that the map surface gradually adjusts to the desired shape, or it can be performed by modifying the map surface in a single step. In either case, the end result is that the identified regions of the map surface are brought within a short distance of the nearest measurement point and can therefore be appropriately colored or otherwise marked to represent the measured physiological data. This map adjustment process can be performed automatically across the entire region of the 3D anatomical map, or alternatively, across specific selected regions.

[0010] Thus, examples of the present disclosure provide a mapping method in which a processor calculates an initial 3D morphology representing the interior surface of a cavity in a living body. The processor also receives physiological data measured at multiple points distributed across the interior surface of the cavity. In the examples described below, the 3D morphology is assumed to be an anatomical map of the heart chamber derived from a point cloud collected by a catheter using the FAM algorithm, and the physiological data is based on electrical measurements made on the endocardial surface of the heart chamber. Alternatively, the principles of the present disclosure may be applied to other body cavities and mapping techniques, as well as other types of physiological data.

[0011] For some or all regions of the initial 3D morphology, the processor calculates the respective distances from the regions to the nearest measurement points and thus identifies any regions whose respective distances are greater than a specified threshold distance. Assuming map coloring is used to represent the physiological data, these regions are colored gray. The processor then modifies the initial 3D morphology to bring each of these identified regions within a specified threshold distance of at least one of the plurality of points. The processor then renders a 3D map of the cavity on the display based on the modified 3D morphology and the measured physiological data.

[0012] System Description 1 illustrates an exemplary catheter-based electrophysiology mapping and ablation system 20. The system 20 may include multiple catheters that are percutaneously inserted by a physician 22 through the vascular system of a patient 23 and into the cavities or vasculature of a heart 24. Typically, a delivery sheath (not shown) is inserted into the left or right atrium near a desired location in the heart 24. One or more catheters 26 are then inserted through the delivery sheath to reach the desired location within the heart 24. The multiple catheters may include catheters dedicated to sensing intracardiac electrogram (IEGM) signals, catheters dedicated to ablation, and / or catheters used for both sensing and ablation.

[0013] The distal portion of the catheter 26 in the illustrated example includes a basket assembly 28. The physician 22 can manipulate the catheter 26 to place the basket assembly 28 in contact with the heart wall to sense a target site within the heart 24 and / or ablate tissue at the target site. Alternatively, the catheter 26 can include other types of distal assemblies, such as multiple flexible arms, a spiral "lasso," or simply a straight distal portion.

[0014] Catheter 26 is an exemplary catheter that includes multiple electrodes 30 distributed across multiple spines 32 in basket assembly 28 and configured to sense IEGM signals and / or ablate cardiomyocytes. Catheter 26 further includes one or more position sensors 34 embedded in a distal portion of the catheter for tracking the position and orientation of basket assembly 28, as described further below. For example, position sensor 34 may include a magnetic position sensor including three magnetic coils for sensing three-dimensional (3D) position and orientation.

[0015] The magnetic position sensor 34 may operate in conjunction with a location pad 36 that includes a plurality of magnetic coils 38 configured to generate a magnetic field within a predetermined working volume that includes the heart 24. The position of the basket assembly 28 of the catheter 26 may be tracked based on the magnetic field generated by the location pad 36 and sensed by the magnetic position sensor 34. Details of magnetic position sensing techniques that may be applied for this purpose are described, for example, in U.S. Patent Nos. 5,5391,199; 5,443,489; 5,558,091; 6,172,499; 6,239,724; 6,332,089; 6,484,118; 6,618,612; 6,690,963; 6,788,967; and 6,892,091.

[0016] System 20 optionally includes one or more electrode patches 40 positioned for skin contact on patient 23 to establish a position reference for location pads 36 and impedance-based tracking of electrodes 30. For impedance-based tracking, current is directed to electrodes 30 and sensed at electrode patches 40, thereby allowing the position of each electrode 30 to be triangulated via electrode patches 40. Details of this type of impedance-based position tracking technology are described in U.S. Patent Nos. 7,536,218; 7,756,576; 7,848,787; 7,869,865; and 8,456,182.

[0017] Recorder 42 records and displays electrograms 44 captured by body surface ECG electrodes 46 and intracardiac electrograms (IEGMs) captured by electrodes 30 of catheter 26. Recorder 42 may include pacing capability for pacing the cardiac rhythm and / or may be electrically connected to a stand-alone pacer.

[0018] System 20 may include an ablation energy generator 48 to provide ablation energy to one or more of electrodes 30. The energy generated by ablation energy generator 48 may include, but is not limited to, radiofrequency (RF) energy or pulsed-field ablation (PFA) energy, including monopolar or bipolar high-voltage DC pulses, such as may be used to effect irreversible electroporation (IRE), or a combination thereof.

[0019] A patient interface unit (PIU) 50 includes an interface for electrical communication between catheters 26, other electrophysiology equipment, a power source, and a computer workstation 52 that controls the operation of system 20. The electrophysiology equipment in system 20 may include, for example, multiple catheters 26, location pads 36, body surface ECG electrodes 46, electrode patches 40, ablation energy generators 48, and recorders 42. Optionally, PIU 50 further includes processing capabilities for implementing real-time calculations of catheter position and processing ECG signals.

[0020] The workstation 52 includes a memory, a processor, and has appropriate operating software stored in the memory, including software for performing the mapping functions described herein, and user interface capabilities. The software may be stored on a tangible, non-transitory, computer-readable medium, such as an optical, magnetic, or electronic storage medium. The workstation 52 may optionally provide multiple functions, including: (1) modeling endocardial anatomy in three dimensions (3D) and rendering the model or anatomical map 54 for display on a display device 56; (2) displaying on the display device 56 activation sequences (or other data) compiled from recorded electrograms 44 with representative visual indicia or images superimposed on the rendered anatomical map 54; (3) displaying the real-time position and orientation of one or more catheters within the heart 24; and (4) displaying on the display screen 56 sites of interest, such as where ablation energy has been applied. A commercially available product that embodies elements of system 20 is the CARTO® 3 System available from Biosense Webster, Inc. (31A Technology Drive, Irvine, CA 92618).

[0021] Mapping Method For convenience and clarity, the method for generating and displaying electroanatomical maps is described below with specific reference to catheter 26, workstation 52, and other elements of system 20, as shown in Figure 1. Alternatively, the principles of the present disclosure may be applied using data acquired by other types of probes and systems, and may be applied to other organs and cavities within the body, and to other types of physiological data.

[0022] 2 is a schematic, pictorial illustration of an initial electroanatomical map 60 of a heart chamber, according to one example of the present disclosure. As discussed above, a processor, such as a processor in workstation 52, creates map 60 based on information provided by catheter 26 via PIU 50. This information includes position coordinates and electrical signals acquired while basket assembly 28 (or another type of distal assembly on catheter 26) is moved within the heart chamber.

[0023] The outer surface 62 of map 60 corresponds to the estimated shape of the endocardial surface of the heart chamber. Surface 62 is created by a technique such as Fast Anatomical Mapping (FAM) and includes a polygonal mesh, e.g., a triangular mesh, that includes the extent of the movement of the distal portion of the catheter within the heart. In other words, surface 62 bounds a certain volume of the point cloud, within which the distal portion of the catheter was moved, but not outside of that volume. Surface 62 may be reconstructed, for example, using a ball-pivot algorithm as described in U.S. Pat. No. 6,968,299, or any other suitable method of surface reconstruction known in the art. Map 60 represents the initial 3D morphology calculated by workstation 52 based on the acquired point cloud, prior to the "shaving" process described below.

[0024] Surface 62 is colored on display device 56 to represent physiological data measured at different points on the endocardium surface. In this example, the physiological data is assumed to include electrical data, and the colors of different regions on the surface represent local values ​​of electrophysiological parameters, such as unipolar voltage or local activation time (LAT). Each region of surface 62 is colored according to the value of the electrical data measured at the point closest to that region. Colors may be interpolated to provide smooth transitions.

[0025] However, regions 64 and 66 in Figure 2 are colored gray, meaning that the nearest electrical measurement point to each of these regions was more than a certain threshold distance away. As explained above, these gray regions may arise due to the "expansion" of the point cloud used in the FAM algorithm relative to the actual endocardium surface. The threshold distance for coloring may be fixed automatically or by a user of system 20, or may be adaptively determined, for example, based on statistics of data acquired from catheter 26.

[0026] 3 is a schematic cross-sectional view of an electroanatomical map 60 illustrating a method for applying electrical data to the map, according to one embodiment of the present disclosure. System 20 acquires electrical data at a set of measurement points 72 distributed across a myocardial surface 74 of a heart chamber 68. Each point 72 is projected onto the nearest triangle among a set of triangles 70 (or other polygons) that make up a mesh created from the point cloud using the FAM algorithm. However, in region 66, triangle 76 is separated from surface 74, and thus from the nearest measurement point 72, by more than a threshold distance. Therefore, given the initial 3D form of map 60, triangle 76 is not colored and remains gray.

[0027] 4 is a flowchart that generally illustrates a method for generating an electro-anatomical map, according to an embodiment of the present disclosure. The method begins, in a data acquisition step 80, by receiving an anatomical point cloud of location points acquired within the heart chamber, as well as electrical measurements taken at points on the endocardial surface of the heart chamber. The location points and electrical data may be acquired in real time from the catheter 26 by the workstation 52, or may be stored in memory and later retrieved by a computer that performs the method. In either case, the workstation 52 generates an initial anatomical map, in a map generation step 82, by, for example, applying an FAM process to the point cloud generated by the catheter 26. As previously mentioned, the anatomical map typically has the form of a triangular mesh (or other polygonal mesh).

[0028] The workstation 52 sets a fill color threshold for all regions of the initial anatomical map in a threshold setting step 84. As previously mentioned, the threshold represents the maximum allowable distance between a measurement point 72 and a triangle 70 (FIG. 3) and may be fixed or may vary adaptively across regions of the map. The workstation 52 measures the distance from each triangle 70 to the nearest measurement point 72 in a coloring step 86. Triangles within a threshold distance of the nearest measurement point are colored according to the value of the electrophysiological parameter measured at the corresponding point. Triangles 76 beyond the threshold distance remain uncolored.

[0029] The distance measured in step 86 may be defined in various ways. For example, workstation 52 may measure the geodesic distance of each vertex of the mesh from the nearest measurement point. When all vertices of a given triangle are beyond the threshold distance, the triangle remains uncolored. When all vertices are within the threshold distance, the triangle is colored. When one or two vertices of a given triangle are beyond the threshold distance and the other vertices are within the threshold distance, the workstation may divide the triangle into a closer portion and a farther portion and then color only the closer portion.

[0030] After the initial map is colored, the workstation 52 identifies regions of the map that are not colored in a gray identification step 88. The workstation reviews this set of gray regions to exclude regions that should not be shaved (e.g., because they represent anatomical features) or otherwise avoid removing too much volume of the initial map. The workstation 52 then shaves a specific volume of the initial map below each of the uncolored triangles (other than the areas excluded from the shaving operation in step 88) in a shaving step 90. For purposes of shaving, the workstation 52 may calculate the volume of the point cloud that falls inside the initial map surface to a specified depth below each uncolored triangle, e.g., 2 mm, and then erase the portion of the point cloud within this volume.

[0031] After the volume under the uncolored triangles has been shaved, workstation 52 reconstructs a triangular mesh at least near the shaved region in a map geometry update step 92. This reconstruction can use the same FAM algorithm used in step 82, but now results in a reduced volume of anatomical map in the uncolored region. In the shaved map region, workstation 52 repeatedly measures the distance from the triangles to the nearest measurement point and appropriately colors triangles that are now within the threshold distance.

[0032] After completing the update in step 92, workstation 52 checks, in a completion check step 94, whether any regions of the map remain uncolored (other than those excluded from the shaving process). If so, workstation 52 repeats steps 88, 90, and 92 for these uncolored regions. In repeating step 90, the workstation iteratively removes additional volumes beneath any uncolored triangles remaining in the modified triangular mesh created by the previous passes of steps 90 and 92. These iterations typically continue until all remaining uncolored triangles are within a threshold distance of the nearest measurement point and are colored accordingly. When workstation 52 finds that this iterative process is complete in step 94, it outputs the final, fully colored 3D map, for example, by rendering the map on display device 56.

[0033] 5 and 6 are schematic depictions of electroanatomical maps 100, 102 at successive stages of map surface modification, according to an embodiment of the present disclosure. In map 100, the large gray region 66 of map 60 (FIG. 2) has been reduced in size by a first shaving iteration. In map 102, region 66 has been removed by further shaving, and this portion of the map is colored entirely. (In this example, gray region 64 has not yet been shaved.) [Example]

[0034] Example 1: A method for mapping includes calculating an initial three-dimensional (3D) morphology representing an interior surface of a cavity within the body of a living organism (23); for each region (70, 76) of a plurality of regions of the initial 3D morphology, receiving measured physiological data at a plurality of points distributed across the interior surface of the cavity; calculating a respective distance from the region to a nearest point of the plurality of points; identifying one or more of the regions whose respective distances are greater than a specified threshold distance; modifying the initial 3D morphology to bring each of the identified regions within the specified threshold distance of at least one point of the plurality of points; and rendering a 3D map (102) of the cavity on a display (56) based on the modified 3D morphology and the measured physiological data.

[0035] Example 2: The method of Example 1, wherein calculating the initial 3D morphology includes receiving a point cloud including multiple position coordinates of the probe acquired while the probe moves within the cavity, and modeling the outer surface of the point cloud to find the initial 3D morphology of the inner surface of the cavity.

[0036] Example 3: The method described in Example 1 or 2, wherein calculating the initial 3D shape includes constructing a polygonal mesh representing the inner surface of the cavity, and calculating the respective distances includes finding the respective distances from each polygon in the mesh to the closest point of the plurality of points.

[0037] Example 4: Identifying one or more of the regions includes identifying polygons having respective distances to respective points of the plurality of points greater than a specified threshold; 4. The method of example 3, wherein modifying the initial 3D form includes removing a volume of the initial 3D form that falls within a specified depth below the identified polygon, and reconstructing a polygonal mesh in the vicinity of the removed volume.

[0038] Example 5: The method described in Example 4, including, after reconstructing the polygonal mesh, recalculating the distance from the polygon to each of the nearest points among the plurality of points, and when the recalculated distance is still greater than a specified threshold, iteratively removing one or more additional volumes below the modified polygonal mesh until the recalculated distance is less than or equal to the specified threshold.

[0039] Example 6: The method of any one of Examples 3 to 5, wherein constructing the polygonal mesh includes constructing a triangular mesh, and finding each distance includes measuring the geodesic distance from each vertex of each triangle in the mesh to each point among a plurality of points closest to the vertex.

[0040] Example 7: The method of any one of Examples 1 to 6, wherein receiving physiological data includes receiving electrophysiological data acquired at multiple points by an intracavitary probe.

[0041] Example 8: The method described in Example 7, wherein receiving electrophysiological data includes receiving electrical signals measured by a catheter within a chamber of a heart of a living subject, and rendering a 3D map includes generating an electroanatomical map of the chamber.

[0042] Example 9: A method described in any one of Examples 1 to 8, wherein rendering the 3D map includes coloring the region of the modified 3D form presented on the display according to the value of the physiological data measured at the point closest to the region.

[0043] Example 10. A system (20) for mapping comprises an interface (50) configured to receive physiological data measured at a plurality of points distributed across an inner surface of a cavity within the body of a living organism (23); and a processor (52) configured to calculate an initial three-dimensional (3D) morphology representing the inner surface of the cavity, calculate for each region (70, 76) of a plurality of regions of the initial 3D morphology a respective distance from the region to a nearest point of the plurality of points, identify one or more of the regions whose respective distances are greater than a specified threshold distance, modify the initial 3D morphology to bring each of the identified regions within the specified threshold distance of at least one point of the plurality of points, and render a 3D map (102) of the cavity on a display (56) based on the modified 3D morphology and the measured physiological data.

[0044] Example 11. A computer software product comprising a tangible, non-transitory computer-readable medium having stored thereon program instructions that, when read by a computer (52), cause the computer to receive physiological data measured at a plurality of points distributed across an interior surface of a cavity within the body of a living organism, calculate an initial three-dimensional (3D) morphology representing the interior surface of the cavity, calculate, for each region (70, 76) of a plurality of regions of the initial 3D morphology, a respective distance from the region to a nearest point of the plurality of points, identify one or more of the regions whose respective distances are greater than a specified threshold distance, modify the initial 3D morphology to bring each of the identified regions within the specified threshold distance of at least one point of the plurality of points, and render a 3D map (102) of the cavity on a display (56) based on the modified 3D morphology and the measured physiological data.

[0045] The implementations described above are cited by way of example, and the present disclosure is not limited to that specifically shown and described in the foregoing specification. Rather, the scope of the present disclosure includes both combinations and subcombinations of the various features described hereinabove, as well as variations and modifications thereof not disclosed in the prior art that would occur to one skilled in the art upon reading the foregoing description.

[0046] [Embodiment] (1) A method for mapping, comprising: calculating an initial three-dimensional (3D) morphology representing the interior surface of a cavity within the body of a living organism; receiving physiological data measured at a plurality of points distributed across the interior surface of the cavity; calculating, for each region of the plurality of regions of the initial 3D form, a respective distance from the region to a nearest point of the plurality of points; identifying one or more of the regions, wherein the respective distance is greater than a specified threshold distance; modifying the initial 3D form to bring each of the identified regions within the specified threshold distance of at least one of the plurality of points; and rendering a 3D map of the cavity on a display based on the modified 3D morphology and the measured physiological data. (2) The method of embodiment 1, wherein calculating the initial 3D form includes receiving a point cloud including multiple position coordinates of the probe acquired while the probe moves within the cavity, and modeling the outer surface of the point cloud to find the initial 3D form of the inner surface of the cavity. (3) The method of embodiment 1, wherein calculating the initial 3D form includes constructing a polygonal mesh representing the inner surface of the cavity, and calculating the respective distances includes finding the respective distances from each polygon in the mesh to the closest point of the plurality of points. (4) identifying one or more of the regions includes identifying polygons whose respective distances to the respective points of the plurality of points are greater than the specified threshold; 4. The method of claim 3, wherein modifying the initial 3D form includes removing a volume of the initial 3D form that falls within a specified depth below the identified polygon, and reconstructing the polygonal mesh in the vicinity of the removed volume. (5) A method according to embodiment 4, comprising, after reconstructing the polygonal mesh, recalculating the distance from the polygon to each of the nearest points of the plurality of points, and when the recalculated distance is still greater than the specified threshold, iteratively removing one or more additional volumes below the modified polygonal mesh until the recalculated distance is less than or equal to the specified threshold.

[0047] (6) The method of embodiment 3, wherein constructing the polygonal mesh includes constructing a triangular mesh, and finding the respective distances includes measuring the geodesic distance from each vertex of each triangle in the mesh to each point of the plurality of points that is closest to the vertex. (7) The method of embodiment 1, wherein receiving the physiological data includes receiving electrophysiological data acquired at the plurality of points by a probe within the cavity. (8) The method of embodiment 7, wherein receiving the electrophysiological data includes receiving electrical signals measured by a catheter within a chamber of the living body's heart, and rendering the 3D map includes generating an electroanatomical map of the chamber. (9) The method of embodiment 1, wherein rendering the 3D map includes coloring the region of the modified 3D form presented on the display according to the value of the physiological data measured at the point closest to the region. (10) A system for mapping, comprising: an interface configured to receive physiological data measured at a plurality of points distributed across an interior surface of a cavity within a body of a living subject; a processor configured to calculate an initial three-dimensional (3D) morphology representing an inner surface of the cavity; calculate, for each region of a plurality of regions of the initial 3D morphology, a respective distance from the region to a nearest point of the plurality of points; identify one or more of the regions for which the respective distance is greater than a specified threshold distance; modify the initial 3D morphology to bring each of the identified regions within the specified threshold distance of at least one point of the plurality of points; and render a 3D map of the cavity on a display based on the modified 3D morphology and the measured physiological data.

[0048] (11) The system of embodiment 10, wherein the processor is configured to receive a point cloud including multiple position coordinates of the probe acquired while the probe is moving within the cavity, and to model the outer surface of the point cloud to find the initial 3D morphology of the inner surface of the cavity. (12) The system of embodiment 10, wherein the initial 3D form includes a polygonal mesh representing the inner surface of the cavity, and the processor is configured to calculate the respective distances from each polygon in the mesh to the closest point of the plurality of points. (13) The system of embodiment 12, wherein the processor is configured to modify the initial 3D form by identifying polygons whose respective distances to the respective points of the plurality of points are greater than the specified threshold, removing a volume of the initial 3D form that falls within a specified depth below the identified polygon, and reconstructing the polygonal mesh in the vicinity of the removed volume. (14) The system of embodiment 13, wherein the processor is configured to, after reconstructing the polygonal mesh, recalculate the distance from the polygon to each of the nearest points of the plurality of points, and when the recalculated distance is still greater than the specified threshold, iteratively remove one or more additional volumes below the modified polygonal mesh until the recalculated distance is less than or equal to the specified threshold. (15) The system of embodiment 12, wherein the polygonal mesh includes a triangular mesh, and the processor is configured to calculate each distance by measuring the geodesic distance from each vertex of each triangle in the mesh to a respective point of the plurality of points that is closest to the vertex.

[0049] (16) The system of embodiment 10, wherein the physiological data includes electrophysiological data acquired at the plurality of points by the intracavitary probe. (17) The system of embodiment 16, comprising a catheter configured to provide the electrophysiological data by measuring electrical signals within a chamber of the living body's heart, and the 3D map includes an electroanatomical map of the chamber. (18) The system of embodiment 10, wherein the processor is configured to color the region of the modified 3D form presented on the display according to the value of the physiological data measured at the point closest to the region. (19) A computer software product including a tangible, non-transitory computer-readable medium having stored thereon program instructions that, when read by a computer, cause the computer to receive physiological data measured at a plurality of points distributed across an interior surface of a cavity within the body of a living organism, calculate an initial three-dimensional (3D) morphology representing the interior surface of the cavity, calculate, for each region of a plurality of regions of the initial 3D morphology, a respective distance from the region to a nearest point of the plurality of points, identify one or more of the regions for which the respective distance is greater than a specified threshold distance, modify the initial 3D morphology to bring each of the identified regions within the specified threshold distance of at least one point of the plurality of points, and render on a display a 3D map of the cavity based on the modified 3D morphology and the measured physiological data. (20) The product of embodiment 19, wherein the instructions cause the computer to receive a point cloud including a plurality of position coordinates of the probe acquired while the probe is moving within the cavity, and model the outer surface of the point cloud to find the initial 3D morphology of the inner surface of the cavity.

[0050] (21) The product of embodiment 19, wherein the initial 3D form includes a polygonal mesh representing the interior surface of the cavity, and the instructions cause the computer to calculate the respective distances from each polygon in the mesh to the closest point of the plurality of points. (22) The product of claim 21, wherein the instructions cause the computer to identify polygons whose respective distances to the respective points of the plurality of points are greater than the specified threshold, remove volumes of the initial 3D form that fall within a specified depth below the identified polygons, and reconstruct the polygonal mesh in the vicinity of the removed volumes. (23) The product of claim 22, wherein the instructions cause the computer to, after reconstructing the polygonal mesh, recalculate the distance from the polygon to each of the nearest points of the plurality of points, and, if the recalculated distance is still greater than the specified threshold, iteratively remove one or more additional volumes below the modified polygonal mesh until the recalculated distance is less than or equal to the specified threshold. (24) The product of claim 21, wherein the polygonal mesh comprises a triangular mesh, and the instructions cause the computer to calculate each distance by measuring the geodesic distance from each vertex of each triangle in the mesh to a respective point in the plurality of points that is closest to the vertex. (25) The product of embodiment 19, wherein the physiological data includes electrophysiological data acquired at the plurality of points by the intracavitary probe.

[0051] (26) The product of claim 25, wherein the instructions cause the computer to obtain the electrophysiological data by processing electrical signals measured by a catheter within a chamber of the living body's heart and to generate an electroanatomical map of the chamber using the electrophysiological data. (27) The product of claim 19, wherein the instructions cause the computer to color the region of the modified 3D form presented on the display according to the value of the physiological data measured at the point closest to the region.

Claims

1. 1. A system for mapping, comprising: an interface configured to receive physiological data measured at a plurality of points distributed across an interior surface of a cavity within a body of a living subject; a processor configured to calculate an initial three-dimensional (3D) morphology representing an inner surface of the cavity; calculate, for each region of a plurality of regions of the initial 3D morphology, a respective distance from the region to a nearest point of the plurality of points; identify one or more of the regions for which the respective distance is greater than a specified threshold distance; modify the initial 3D morphology to bring each of the identified regions within the specified threshold distance of at least one point of the plurality of points; and render a 3D map of the cavity on a display based on the modified 3D morphology and the measured physiological data.

2. 2. The system of claim 1, wherein the processor is configured to receive a point cloud including a plurality of position coordinates of the probe acquired while the probe is moving within the cavity, and to model an exterior surface of the point cloud to find the initial 3D morphology of the interior surface of the cavity.

3. 2. The system of claim 1, wherein the initial 3D form includes a polygonal mesh representing the interior surface of the cavity, and the processor is configured to calculate the respective distances from each polygon in the mesh to a nearest point of the plurality of points.

4. 4. The system of claim 3, wherein the processor is configured to modify the initial 3D form by identifying polygons whose respective distances to the respective points of the plurality of points are greater than the specified threshold, removing a volume of the initial 3D form that falls within a specified depth below the identified polygon, and reconstructing the polygonal mesh near the removed volume.

5. 5. The system of claim 4, wherein the processor is configured to, after reconstructing the polygonal mesh, recalculate the distance from the polygon to each of the nearest points of the plurality of points, and if the recalculated distance is still greater than the specified threshold, iteratively remove one or more additional volumes below the modified polygonal mesh until the recalculated distance is less than or equal to the specified threshold.

6. 4. The system of claim 3, wherein the polygonal mesh comprises a triangular mesh, and the processor is configured to calculate each distance by measuring the geodesic distance from each vertex of each triangle in the mesh to a respective point in the plurality of points that is closest to the vertex.

7. The system of claim 1 , wherein the physiological data comprises electrophysiological data acquired at the plurality of points by the intracavitary probe.

8. 8. The system of claim 7, comprising a catheter configured to provide the electrophysiological data by measuring electrical signals within a chamber of the living body's heart, and wherein the 3D map comprises an electroanatomical map of the heart chamber.

9. 2. The system of claim 1, wherein the processor is configured to color the region of the modified 3D form presented on the display according to a value of the physiological data measured at the point closest to the region.

10. 1. A computer software product comprising a tangible, non-transitory computer-readable medium having stored thereon program instructions that, when read by a computer, cause the computer to receive physiological data measured at a plurality of points distributed across an interior surface of a cavity within the body of a living organism, calculate an initial three-dimensional (3D) morphology representing the interior surface of the cavity, calculate, for each region of a plurality of regions of the initial 3D morphology, a respective distance from the region to a nearest point of the plurality of points, identify one or more of the regions for which the respective distance is greater than a specified threshold distance, modify the initial 3D morphology to bring each of the identified regions within the specified threshold distance of at least one point of the plurality of points, and render on a display a 3D map of the cavity based on the modified 3D morphology and the measured physiological data.

11. 1. A method for mapping, comprising: calculating an initial three-dimensional (3D) morphology representing the interior surface of a cavity within the body of a living organism; receiving physiological data measured at a plurality of points distributed across the interior surface of the cavity; calculating, for each region of a plurality of regions of the initial 3D form, a respective distance from the region to a nearest point of the plurality of points; identifying one or more of the regions where the respective distance is greater than a specified threshold distance; modifying the initial 3D morphology to bring each of the identified regions within the specified threshold distance of at least one of the plurality of points; and rendering a 3D map of the cavity on a display based on the modified 3D morphology and the measured physiological data.

12. 12. The method of claim 11, wherein calculating the initial 3D morphology comprises receiving a point cloud including a plurality of position coordinates of the probe acquired while the probe is moving within the cavity, and modeling an exterior surface of the point cloud to find the initial 3D morphology of the interior surface of the cavity.

13. 12. The method of claim 11 , wherein calculating the initial 3D morphology comprises constructing a polygonal mesh representing the interior surface of the cavity, and calculating the respective distances comprises finding the respective distances from each polygon in the mesh to a closest point of the plurality of points.

14. identifying one or more of the regions includes identifying polygons whose respective distances to the respective points of the plurality of points are greater than the specified threshold; 14. The method of claim 13, wherein modifying the initial 3D form comprises removing a volume of the initial 3D form that falls within a specified depth below the identified polygon, and rebuilding the polygonal mesh near the removed volume.

15. 15. The method of claim 14, comprising: after reconstructing the polygonal mesh, recalculating the distance from the polygon to each of the nearest points of the plurality of points; and, if the recalculated distance is still greater than the specified threshold, iteratively removing one or more additional volumes below the modified polygonal mesh until the recalculated distance is less than or equal to the specified threshold.

16. 14. The method of claim 13, wherein constructing the polygonal mesh includes constructing a triangular mesh, and finding the respective distances includes measuring the geodesic distance from each vertex of each triangle in the mesh to a respective point in the plurality of points that is closest to the vertex.

17. The method of claim 11 , wherein receiving the physiological data comprises receiving electrophysiological data acquired at the plurality of points by the intracavity probe.

18. 18. The method of claim 17, wherein receiving the electrophysiological data comprises receiving electrical signals measured by a catheter within a chamber of the living body's heart, and rendering the 3D map comprises generating an electroanatomical map of the heart chamber.

19. 12. The method of claim 11 , wherein rendering the 3D map comprises coloring the region of the modified 3D form presented on the display according to a value of the physiological data measured at the point closest to the region.

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