Method of semiautomatic segmentation for the estimation of three-dimensional volumes

Claim 1

A method of estimating the volume of a three-dimensional object having a known contour, the object being an organ or organ part of a body, the method comprising: acquiring a plurality of two-dimensional images of the organ or organ part that defines the object; defining a given number of base points on a contour of the object and in a first image of the object, the given number of base points defining facets whose vertices are the base points and which represent a first three dimensional shape of the object; defining each facet of the first shape by three segments wherein each segment is common to two adjacent facets; creating second rank points on the contour of the object by dividing the segments so as to constitute a second three-dimensional shape closer to the contour of the object than the first shape, the creation of each second rank point resulting in the creation of at least two new facets and at least three new segments; defining third or more rank points on the contour of the object by iteratively dividing each new segment into subsegments, so as to represent a third or more three-dimensional shape closer to the contour of the object than the second three-dimensional shape, the creation of the third or more rank points resulting in the creation of at least two additional new facets and at least three additional new segments, the third or more three-dimensional shape forming a final shape from the plurality of facets defined or created, the plurality of facets defining a plurality of triangular surfaces having known vertex points; and estimating the volume of the final shape using the plurality of triangular surfaces and making available to a user of medical imagery the estimation of the volume of the final shape which is representative of the volume of the three-dimensional organ or organ part.

Claim 2

A method of estimating the volume of a three-dimensional object having a known contour, the object being an organ or organ part of a body, the method comprising: acquiring a plurality of two-dimensional images of the organ or organ part that defines the object; defining a given number of base points on a contour of the object and in a first image of the object, the given number of base points defining facets whose vertices are the base points and which represent a first three dimensional shape of the object; defining each facet of the first shape by three segments wherein each segment is common to two adjacent facets; creating second rank points on the contour of the object by dividing the segments so as to constitute a second three-dimensional shape closer to the contour of the object than the first shape, the creation of each second rank point resulting in the creation of at least two new facets and at least three new segments; defining third or more rank points on the contour of the object by iteratively dividing each new segment into subsegments, so as to represent a third or more three-dimensional shape closer to the contour of the object than the second three-dimensional shape, the creation of the third or more rank points resulting in the creation of at least two additional new facets and at least three additional new segments, the third or more three-dimensional shape forming a final shape from the plurality of facets defined or created, the plurality of facets defining a plurality of triangular surfaces having known vertex points; and estimating the volume of the final shape using the plurality of triangular surfaces and making available to a user of medical imagery the estimation of the volume of the final shape which is representative of the volume of the three-dimensional organ or organ part.