Method and device for reconstructing three-dimensional images of blood vessels, particularly coronary arteries, or other three-dimensional structures
First Claim
1. A method for reconstructing a structure having a three-dimensional extension, comprising the stages of:
- obtaining at least three images of the structure to be reconstructed, each of said images showing reference points which permit the determination of a matrix (T) which describes the geometric projections associated with each image;
identifying, by means of said three images, a starting point for the tracing of a center line of an elongate element of said structure;
tracking the center line of the elongate element to an end point;
determining the cross-sectional dimension of said elongate element at a plurality of points of the center line;
reconstructing the three-dimensional image of the elongate element from said cross-sectional dimensions and said center line.
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Abstract
A description is given of a device and a method for reconstructing the three-dimensional structure of blood vessels or other structures. The method comprises the stages of: obtaining at least three images of the blood vessels to be reconstructed, each of said images showing reference points which permit the determination of a matrix (T) which describes the geometric projections associated with each image; identifying, by means of said three images, a starting point for the tracing of a center line of a blood vessel; tracking the center line of the blood vessel to an end point; determining the cross-sectional dimension of said blood vessel at a plurality of points of the center line; reconstructing the three-dimensional image of the blood vessel from said cross-sectional dimensions and said center line.
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Citations
17 Claims
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1. A method for reconstructing a structure having a three-dimensional extension, comprising the stages of:
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obtaining at least three images of the structure to be reconstructed, each of said images showing reference points which permit the determination of a matrix (T) which describes the geometric projections associated with each image;
identifying, by means of said three images, a starting point for the tracing of a center line of an elongate element of said structure;
tracking the center line of the elongate element to an end point;
determining the cross-sectional dimension of said elongate element at a plurality of points of the center line;
reconstructing the three-dimensional image of the elongate element from said cross-sectional dimensions and said center line. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 17)
a) setting the starting point (Pi−
1) and the initial reference direction by means of the vector (di);
b) determining the initial scanning radius and the initial thickness (hi) by the formula;
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4. The method as claimed in claim 1, in which the center line of the elongate element is followed in said first image by means of an algorithm comprising the following stages:
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a) setting the starting point (Pi−
1) and the initial reference direction by means of the vector (di);
b) determining the initial scanning radius and the initial thickness (hi) by the formula;
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5. The method as claimed in claim 4, in which said elongate geometrical figure is a rectangle.
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6. The method as claimed in claim 5, in which said rectangle has sides equal to the scanning radius (ri) and the thickness (hi).
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7. The method as claimed in claim 5, in which said estimated value of the scanning radius is determined by:
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ri+1=|kis−
kid|*1.5where kis and kid are the directions (ks, kd) corresponding to the mean values lying immediately below the set threshold (si) calculated in the preceding step.
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8. The method as claimed in claim 4, in which in each step the scanning radius for the next iteration is determined as the arithmetic mean of the last three calculated values and a fourth estimated value.
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9. The method as claimed in claim 4, in which in every i-th iteration a check is made to determine whether the difference |ks−
- kd| is less than a specified fraction of that calculated during the preceding iteration, and, if this is so, the values obtained are rejected and the search for the next corresponding maximum is continued by continuing the scanning of the vector (li) of means of the gray levels.
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10. The method as claimed in claim 1, in which, for each point of the center line of the elongate element identified on a first of said images, the straight line passing through said point, through the three-dimensional point of which said point is the projection on the first image, and through the source (S1) which has generated the point of the center line on said first image is determined;
- said straight line, or a segment of it, is projected on said second and/or said third image;
the resulting luminosity profile is analyzed by sampling the gray levels of the second and/or third image along the projection of said straight line or said segment of straight line; and
the projection of the three-dimensional point on said second and/or third image is identified as the point of lowest luminosity along the projection of said straight line or said segment of straight line.
- said straight line, or a segment of it, is projected on said second and/or said third image;
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17. The device as claimed in claim 11, comprising processing means for implementing the method as claimed in claim 1.
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11. A device for reconstructing a three-dimensional structure, comprising:
- at least one source of radiation and a receiver for said radiation, the three-dimensional structure being located between said source and said receiver;
an object (9) capable of being associated with the three-dimensional structure and carrying a plurality of radiopaque points; and
means for obtaining at least three images at three different angles of a single three-dimensional structure. - View Dependent Claims (12, 13, 14, 15, 16)
- at least one source of radiation and a receiver for said radiation, the three-dimensional structure being located between said source and said receiver;
Specification