A cardiac segmentation system acquires a series of images acquires as slices through a volume, and as images at different time periods throughout a cardiac cycle. It displays an image to an operator which interactively selects a region of interest (ROI) of the image to be segmented, such as the left ventricle. A seed point is also selected within the ROI and the structure desired to be segmented. The image is then thresholded by a masking device classifying points within the ROI as above the threshold, or not above the threshold. A 3D connectivity device identifies points within the ROI having the same classification as an expanded seed point which are also contiguous with the seed point as the segmented structure. The segmented structure is expanded and a histogram is constructed. A new threshold is selected which separates modes of the histogram, and used to carry out a revised, final, segmentation of the current image. The centroid of the current image is used as a seed point in segmenting adjacent images. Similarly, the current threshold is used as an initial threshold for adjacent images. The previous seed point and ROI may also be used. This is repeated for a number of images to result in segmented structures may then be stored, displayed and used in calculating heart functionality.
CROSS REFERENCE TO PENDING APPLICATIONS
This is a continuation application of U.S. Provisional patent application Ser. No. 60/029,967 filed Nov. 1, 1996, entitled "Fast Segmentation Of Cardiac Images" by Richard I. Hartley, Rupert W. Curwen, and Harvey E. Cline, and claims an effective filing date of that of the parent case.
A method for three dimensional image segmentation of a volume of interest includes providing a three dimensional image of the volume of interest, providing an initial polyhedron having a plurality of mesh vertices within the three dimension image and determining an image-based speed at each vertex of the polyhedron using an ordinary differential equation (ODE) that describes the vertex motion of the polyhedron. The method further includes determining a regularization term at each vertex of the polyhedron, updating the plurality of mesh vertices of the polyhedron, integrating the image-based speed of each vertex over a face of the polyhedron, and determining an output polyhedron approximating a shape of the volume of interest.
An object, such as an example blood vessel, in a two or three dimensional image data set is segmented. An adaptable model, such as an example cylinder model, is defined around a starting point in the example blood vessel and is adapted or fit to the blood vessel. A plurality of candidate next active points are defined around the starting point and the adaptable model is defined around each candidate point. The models around the candidate points are adapted to the blood vessel. Based on results of the fitted models, a next active point is selected. In this manner, the blood vessel is segmented by adapting a series of cylinder models to an inner surface of the blood vessel.
A method for the automated segmentation of an abnormality in a medical image, including acquiring first image data representative of the medical image; locating a suspicious site at which the abnormality may exist; establishing a seed point within the suspicious site; and preprocessing the suspicious site with a constraint function to produce second image data in which pixel values distant of the seed point are suppressed. Preprocessing includes using an isotropic Gaussian function centered on the seed point as the constraint function, or for example using an isotropic three dimensional Gaussian function centered on the seed point as the constraint function. The method further includes applying plural thresholds to the second image data to partition the second image data at each threshold; identifying corresponding first image data for the partitioned second image data obtained at each respective threshold; determining a respective index for each of the partitioned first image data; and determining a preferred partitioning, for example that partitioning leading to a maximum index value, based on the indices determined at each threshold, and segmenting the lesion based on the partitioning established by the threshold resulting in the maximum index. If desired, the first image data with the partitioning defined by the threshold which is determined to result in the maximum index, is then displayed. A system and computer readable storage medium are also provided, likewise using the radial gradient index (RGI) or a simple probabilistic models to segment mass lesions, or other similar nodular structures, from surrounding background. In the system, a series of image partitions is likewise created using gray-level information as well as prior knowledge of the shape of typical mass lesions. When the RGI is used, the partition that maximizes RGI is selected. When a probability model is used, probability distributions for gray-levels inside and outside the partitions are estimated, and subsequently used to determine the probability that the image occurred for each given partition. The partition that maximizes this probability is selected as the final lesion partition (contour).
Ultrasound systems and methods are described to measure changes in cardiac chamber volumes and organ wall areas, thicknesses, volumes and masses between the cardiac chambers using computer readable media employing image processing algorithms applied to 3D data sets acquired at systole and diastole. The systems for cardiac imaging includes an ultrasound transceiver configured to sense the mitral valve of a heart by Doppler ultrasound, an electrocardiograph connected with a patient and synchronized with the transceiver to acquire ultrasound-based 3D data sets during systole and diastole at a transceiver location determined by Doppler ultrasound affected by the mitral valve, and a computer readable medium configurable to process ultrasound imaging information from the 3D data sets communicated from the transceiver.
The invention relates to a method of segmenting an image of a structure stored as a set of spatially related data points representing variations in a predetermined parameter, said method comprising the steps of selecting a seed point within the structure to be segmented, assigning to each of the data points a value of connectivity indicative of the confidence that respective areas of the data points are part of the same structure as said seed point, said value of connectivity including a function of the distance of the respective point from said seed point, establishing a threshold value for said level of connectivity and selecting for display data points meeting said threshold value.