Determining cardiac wall thickness and motion by imaging and three-dimensional modeling
First Claim
1. A method for analyzing characteristic cardiac parameters of a patient'"'"'s heart, comprising the steps of:
- (a) imaging a heart to produce imaging data;
(b) modeling the heart using the imaging data, producing modeling data corresponding to an inner surface and an outer surface of the heart, at a plurality of times during a cardiac cycle, including at an end systole and at an end diastole of the cardiac cycle;
(c) using the inner surface of the heart produced with the modeling data, creating a mesh of connected polygons that represent the inner surface of the heart, said polygons including a plurality of connected edges that meet at vertices of the polygons;
(d) determining a normal for a face of each of the polygons;
(e) determining a vertex normal for each of the vertices by averaging the normals for the faces of the polygons meeting at the vertices;
(f) extending the vertex normals as a plurality of line segments that intersect the outer surface at a plurality of points, said line segments extending between the vertices of the polygons on the inner surface and the points on the outer surface;
(g) connecting midpoints of the line segments to form a mesh having a plurality of connected polygons with vertices disposed at the midpoints of the line segments, said mesh representing the center surface; and
(h) using the center surface represented by the mesh formed by connecting the midpoints of the line segments, determining characteristic cardiac parameters for the heart.
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Abstract
A method for imaging and three-dimensional modeling portions of the heart, particularly the left ventricular endocardial and epicardial surfaces, using imaging data. Preferably, a transesophageal ultrasound probe is inserted into an esophagus of a patient to provide multiple plane imaging data at end systole and end diastole during a cardiac cycle. The image planes are then traced along the boundaries of the epicardial and endocardial surfaces to produce sets of data points, which are further processed and expanded through interpolation. These data points are used for modeling the endocardial and epicardial surface at the end systole and end diastole extremes of the cardiac cycle. A center surface is constructed between an inner and outer surface of the modeled surfaces of the left ventricle and either an average template of tiled sections is mapped onto this center surface, or a mesh of triangular tiled sections representing the inner surface is projected on the center surface to define corresponding numbered tiled sections on the center surface. The tiled sections of the center surface are then projected onto the inner and outer surfaces, defining triangular prisms. By determining the volume of the triangular prisms and an average area for their ends, the range of movement, which is equal to the volume divided by the average area, is determined. Similarly, for changes in wall thickness between the endocardial and epicardial surfaces at end diastole and end systole, the thickening of the cardiac wall is determined.
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Citations
26 Claims
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1. A method for analyzing characteristic cardiac parameters of a patient'"'"'s heart, comprising the steps of:
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(a) imaging a heart to produce imaging data; (b) modeling the heart using the imaging data, producing modeling data corresponding to an inner surface and an outer surface of the heart, at a plurality of times during a cardiac cycle, including at an end systole and at an end diastole of the cardiac cycle; (c) using the inner surface of the heart produced with the modeling data, creating a mesh of connected polygons that represent the inner surface of the heart, said polygons including a plurality of connected edges that meet at vertices of the polygons; (d) determining a normal for a face of each of the polygons; (e) determining a vertex normal for each of the vertices by averaging the normals for the faces of the polygons meeting at the vertices; (f) extending the vertex normals as a plurality of line segments that intersect the outer surface at a plurality of points, said line segments extending between the vertices of the polygons on the inner surface and the points on the outer surface; (g) connecting midpoints of the line segments to form a mesh having a plurality of connected polygons with vertices disposed at the midpoints of the line segments, said mesh representing the center surface; and (h) using the center surface represented by the mesh formed by connecting the midpoints of the line segments, determining characteristic cardiac parameters for the heart. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A method for determining a center surface that is centered between a first surface and a second surface represents a cardiac wall of a patient'"'"'s heart, for use in analyzing characteristic cardiac parameters, said method comprising the steps of:
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(a) defining a first mesh of connected polygons representing the first surface, said connected polygons having vertices and edges along which they are connected; (b) for each vertex, determining a vertex normal by averaging normals to all of the connected polygons surrounding the vertex; (c) extending the vertex normals as line segments that intercept the second surface at a plurality of points; (d) creating a second mesh of connected polygons to represent the center surface, by connecting midpoints of the lines segments, said midpoints comprising vertices of said plurality of connected polygons representing the center surface, and (e) using said center surface for analyzing characteristic cardiac parameters. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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Specification