Image analysis – Applications – Motion or velocity measuring
Reexamination Certificate
1998-10-01
2001-05-22
Johns, Andrew W. (Department: 2721)
Image analysis
Applications
Motion or velocity measuring
Reexamination Certificate
active
06236738
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates generally to magnetic resonance imaging, and more particularly the invention relates to motion analysis using motion data, for example as collected using Phase-Contrast (PC) cine Magnetic Resonance Imaging (MRI).
Methods for the calculation of the motion of a material point or a small region during a motion cycle (e.g. the cardiac cycle) are known. The simplest methods assume that the region being analyzed moves as a rigidly translating body. Deformation can be studied by tracking the motion, and specifically the relative motion, of multiple regions. However, the extraction of information may not be ideal since all the motion data samples within a region may not contribute to the results.
A method that allows for deformation and rotation of a region is also known. Typically, the method assumes that the strain within the region being analyzed is homogeneous. The spatial distribution of velocity within the region is assumed to be a linear function, and this allows for homogenous deformation and rotation. In principle, higher order spatial dependence could be allowed, thereby supporting non-homogeneous strain. However, one would then need to decide the degree of heterogeneity to be supported in a particular application. This depends on the object being studied as well as the size of the region.
SUMMARY OF THE INVENTION
In accordance with the present invention, a method of motion analysis of a moving region within an object comprises the steps of a) obtaining motion data from the moving region for a plurality of time frames, b) identifying a plurality of movable material points within the region, c) defining a spatiotemporal model of the region which relates the kinematics of the region during the plurality of time frames to the material points, and d) computing motion and deformation of the moving region using the motion data and said model. The identified material points can be node points of a dynamic mesh composed of a plurality of non-overlapping elements, including two dimensional elements such as triangles and three dimensional elements such as tetrahedrons.
In accordance with an embodiment, an object undergoing cyclic nonrigid motion such as the heart is modeled as a dynamic finite element mesh, and the motion and deformation (Kinematics) of the entire mesh as a function of time in the cycle is computed using a single spatiotemporal model. Because the object can be divided into many mesh elements, the kinematics within each element can be assumed to be relatively homogenous. Heterogeneity within the object is supported by the number and size of the elements comprising the mesh. Analyzing the object with the spatiotemporal mesh modeling assumes a structured view of the underlying object motion, which facilitates interpreting as well quantifying displacement and strain fields.
The invention and objects and features thereof will be more readily apparent from the following detailed description and appended claims when taken with the drawings.
REFERENCES:
patent: 5109425 (1992-04-01), Lawton
patent: 5257626 (1993-11-01), Pelc et al.
patent: 5600731 (1997-02-01), Sezan et al.
patent: 5875108 (1999-02-01), Hoffberg et al.
patent: 5974360 (1999-10-01), Otsuka et al.
patent: 5983251 (1999-11-01), Martens et al.
patent: 6005625 (1999-12-01), Yokoyama
patent: 6031374 (2000-02-01), Epstein et al.
patent: 6047088 (2000-04-01), van Beek et al.
Pelc Norbert J.
Zhu Yudong
Board of Trustees of the Leland Stanford Junior University
Johns Andrew W.
Nakhjavan Shervin
Townsend and Townsend / and Crew LLP
Woodward Henry K.
LandOfFree
Spatiotemporal finite element method for motion analysis... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Spatiotemporal finite element method for motion analysis..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Spatiotemporal finite element method for motion analysis... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2461774