US 7,353,117 B2 · Computation of wall thickness

Abstract

A method for automatic vessel wall thickness measurement at any point along the perimeter of either luminal or outer vessel wall boundaries. The method employs both Delaunay triangulation and multiresolution tiling. The MaxMin angle property of the Delaunay triangulation is used to define the minimum energy function to calculate thickness. Multiresolution tiling is employed to enable the MaxMin angle lemma to be determined. The triangulation MaxMin angle lemma enables a minimal energy function to be defined based on triangulation angles, providing a stable and consistent geometrical computation. Additional morphological indexes can be assessed to achieve comprehensive quantification of vascular morphology. For example, based on the wall thickness, a set of vascular shape descriptors can be developed to distinguish different types of plaque morphology at different parts of a vessel wall.

Claims44

Dependent claims

A method for estimating a thickness of a wall of a lumen from an image of the lumen, comprising the steps of:

(a) in an image of the lumen, identifying an inner contour and an outer contour;
(b) performing a low resolution triangulation function to define triangles between the inner contour and the outer contour;
(c) adding additional triangles between the inner contour and the outer contour;
(d) analyzing edges of the triangles that were defined and added using a minimal energy function to identify triangle edges that correspond to a width between the inner contour and the outer contour;
(e) comparing triangle edges identified as corresponding to a width between the inner contour and the outer contour to identify a minimum width and a maximum width corresponding respectively to a minimum wall thickness and a maximum wall thickness of the lumen;
and
(f) having identified the minimum width and the maximum width, executing at least one step selected from the group consisting of the following steps:
(i) storing indications of the minimum width and the maximum width such that the indications are available for later use by a user;
and
(ii) outputting indications of the minimum width and the maximum width to a user.

7 more elements

A method for estimating a thickness of a wall of a lumen, comprising the steps of:

(a) identifying an inner contour and an outer contour of a lumen;
(b) decomposing each of the inner contour and outer contour into a low resolution set of discrete points for the inner contour and a low resolution set of discrete points for the outer contour;
(c) employing a triangulation function to define triangles between the discrete points in each low resolution set;
(d) adding additional triangles between the inner contour and the outer contour;
(e) analyzing edges of the triangles that were defined and added to identify triangle edges that correspond to a width between the inner contour and the outer contour;
(f) comparing the triangle edges to identify a minimum width and a maximum width;
and
(g) having identified the minimum width and the maximum width, executing at least one step selected from the group consisting of the following steps:
(i) storing indications of the minimum width and the maximum width such that the indications are available for later use by a user;
and
(ii) outputting indications of the minimum width and the maximum width to a user.

8 more elements

A method for estimating a thickness of a wall of a lumen, comprising the steps of:

(a) identifying an inner contour and an outer contour of the lumen;
(b) decomposing the inner contour and the outer contour into a set of low resolution contours, to produce a pair of low resolution contour sets;
(c) computing tiling to generate triangles for each low resolution contour set in which each triangle includes at least one cross edge extending between the inner contour and the outer contour;
(d) labeling each cross edge as a suspect edge;
(e) edge flipping each triangle relative to a cross edge thereof using a minimal energy function to identify cross edges that correspond to the width between the inner contour and the outer contour;
(h) inserting a new vertex into each low resolution contour set, such that triangles defined by the pair of low resolution contour sets are converted to quadrilaterals;
(g) constructing an edge from each inserted vertex in one of the low resolution sets of the pair to a corresponding quadrilateral vertex in the other low resolution contour set of the pair, to convert each quadrilateral into a pair of triangles;
(h) labeling each cross edge as a suspect edge;
(i) edge flipping each triangle relative to a cross edge thereof using the minimal energy function, to identify cross edges that correspond to the width between the inner contour and the outer contour;
(j) repeating steps (f)-(i) until a desired resolution is achieved;
(k) comparing cross edges identified as corresponding to the width between the inner contour and the outer contour to identify a minimum width and a maximum width;
and
(l) having identified the minimum width and the maximum width, executing at least one step selected from the group consisting of the following steps:
(i) storing indications of the minimum width and the maximum width such that the indications are available for later use by a user;
and
(ii) outputting indications of the minimum width and the maximum width to a user.

13 more elements

A system for analyzing a lumen to determine dimensions of the lumen, including wall thickness, comprising:

(a) imaging apparatus that produce an image of a lumen within a body of a patient;
and
(b) a computing device coupled to the imaging apparatus to control it, said computing device including:
(i) a memory in which machine instructions are stored;
and
(ii) a processor coupled to the memory, said processor executing the machine instructions to control the imaging apparatus to carry out a plurality of operations, including:
(1) identifying an inner contour and an outer contour of the lumen;
(2) generating a plurality of edges between the inner contour and the outer contour using multiresolution tiling;
(3) analyzing the plurality of edges using a Delaunay triangulation minimal energy fUnction to identify edges that correspond to a width between the inner contour and the outer contour;
(4) comparing edges identified as corresponding to a width between the inner contour and the outer contour to identify a minimum width and a maximum width between the inner contour and the outer contour, corresponding respectively to a minimum wall thickness and a maximum wall thickness of the lumen;
and
(5) having identified the minimum width and the maximum width, executing at least one step selected from the group consisting of the following steps:
(i) storing indications of the minimum width and the maximum width such that the indications are available for later use by a user;
and
(ii) outputting indications of the minimum width and the maximum width to a user.

12 more elements

A system for analyzing a lumen to determine dimensions of the lumen, including wall thickness, comprising:

(a) a computer configured to process an image of a lumen, said computer including:
(i) a memory in which machine instructions are stored;
(ii) a display configured to display an image of a lumen;
and
(iii) a processor coupled to the memory and the display, said processor executing the machine instructions to carry out a plurality of operations, including:
(1) in an image of the lumen, identifying an inner contour and an outer contour;
(2) performing a low resolution triangulation function to define triangles between the inner contour and the outer contour;
(3) adding additional triangles between the inner contour and the outer contour;
(4) analyzing edges of the triangles that were defined and added using a minimal energy function to identify triangle edges that correspond to a width between the inner contour and the outer contour;
(5) comparing triangle edges identified as corresponding to a width between the inner contour and the outer contour to identify a minimum width and a maximum width corresponding respectively to a minimum wall thickness and a maximum wall thickness of the lumen;
and
(6) having identified the minimum width and the maximum width, executing at least one step selected from the group consisting of the following steps:
(i) storing indications of the minimum width and the maximum width such that the indications are available for later use by a user;
and
(ii) outputting indications of the minimum width and the maximum width to a user.

12 more elements

Dependencies are inferred from the claim text.

Computation of wall thickness

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Computation of wall thickness

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Abstract

Claims44