Abstract: A method and system for segmenting three-dimensional (3D) medical images containing an object of interest are provided. The method comprises generating a plurality of successive layers of fixed radius spheres about a circumference of a sphere containing at least one seed point placed within the object of interest when a plurality of respective voxels contained within the spheres exceed a selected threshold. The generation of the layers is repeated until no further voxels contained within an outer surface of each respective layer exceed the selected threshold or a stop seed point is encountered. The layers form a segmented representation of the object of interest.

Abstract: In an alternate technique, a magnetic resonance imaging system comprises a set of gradient coils for producing controlled gradient field; a radio frequency coil for applying excitation signals to a subject of interest; a detecting coil for detecting magnetic resonance signals resulting from the excitation signals; and a control circuitry configured to energize the set of gradient coils, the radio frequency coil and to obtain a three dimensional phase wrapped image from the magnetic resonance signals detected by the detecting coils, and the control circuitry comprising a phase unwrap component to perform phase unwrapping in a volume of interest of the phase wrapped image to obtain a phase unwrapped image.

Abstract: A method and system for segmenting three-dimensional (3D) medical images containing an object of interest are provided. The method comprises generating a plurality of successive layers of fixed radius spheres about a circumference of a sphere containing at least one seed point placed within the object of interest when a plurality of respective voxels contained within the spheres exceed a selected threshold. The generation of the layers is repeated until no further voxels contained within an outer surface of each respective layer exceed the selected threshold or a stop seed point is encountered. The layers form a segmented representation of the object of interest.

Abstract: An imaging system enables cardiac functioning within a particular cardiac chamber to be imaged. The system acquires imaging data that includes intensity values for four-dimensional voxels within a region of interest (ROI). A seed voxel is identified, and neighbor voxels to the seed voxel are also identified. The intensity values for each neighbor voxel are compared to a threshold to determine whether the voxel corresponds to blood or muscle tissue. For each neighbor voxel corresponding to blood, its neighbor voxels are identified and compared to the threshold, and this process is repeated until a pre-established spatial boundary is encountered or the number of new neighbor voxels indicates that processing is migrating into an adjacent cardiac chamber. At that point, the identified blood voxels are counted into bins of cardiac phases, cardiac images for each phase are reconstructed, and parameters such as ejection fraction are calculated.

Abstract: An imaging system enables cardiac functioning within a particular cardiac chamber to be imaged. The system acquires imaging data that includes intensity values for four-dimensional voxels within a region of interest (ROI). A seed voxel is identified, and neighbor voxels to the seed voxel are also identified. The intensity values for each neighbor voxel are compared to a threshold to determine whether the voxel corresponds to blood or muscle tissue. For each neighbor voxel corresponding to blood, its neighbor voxels are identified and compared to the threshold, and this process is repeated until a pre-established spatial boundary is encountered or the number of new neighbor voxels indicates that processing is migrating into an adjacent cardiac chamber. At that point, the set of identified blood voxels represents a blood volume for the desired cardiac chamber. Voxels adjacent to the interior and exterior surface boundaries of the blood volume are added to the set.

Abstract: Anisotropic data having data spacing significantly larger between layers of data compared with spacing between adjacent data values, is supplemented with additional data to approximate isometric data. The ratio of spacing in one dimension to another is referred to as an aspect ratio A. Preferably, spacing is halved until spacing a modified aspect ratio A′ is near unity. Intermediate values are interpolated between existing values of the anisotropic data to create approximate isotropic data having a modified aspect ratio A′. Surface voxels are determined from the approximate isotropic data. The values of the adjacent voxels are then used to determine a vector normal to the surface at the central voxel. This is repeated for a number of central voxels to determine a surface. The viewing elevation angle is converted to an effective elevation angle. The surface is then rendered into a 2D screen image as if it were created from isotropic data.

Abstract: A system for displaying surfaces of volumetric data determines surface cubes by a simple method without interpolation. A central voxel is selected. The central voxel is tested against a threshold. If it is below the threshold, a different voxel is chosen as a central voxel. When one is found which is above the threshold, diagonal cubes, those at each of the corners of the central voxel, are tested against the threshold. When one is encountered with at least one voxel below the threshold, it is categorized as a surface voxel. The values of the adjacent voxels are then used to determine a vector normal to the surface at the central voxel. This is repeated for a number of central voxels to determine a surface. The surface then may be displayed. If anisotropic voxels are used, the elevation angle is converted to an effective elevation angle. The normal vectors to the surface are also adjusted to compensate for the anisotropic nature of the data.

Abstract: A method for providing a volumetrically-rendered projection image using reverse ray casting, uses the steps of: acquiring, from an object volume of interest, a set of data sampled from each volume element (voxel) therein responsive to a selected characteristic of that object volume; storing the data for each object voxel in a corresponding data volume element; scanning sequentially through each data voxel within the data volume corresponding to the object volume of interest; projecting each scanned data voxel to an image plane, at a solid angle determined from the solid angle at which the object volume is viewed; storing a value for each image plane pixel, responsive to a selected criteria, from the values of all projected data voxel values impingent upon that image plane pixel; and then scaling the dimensions of each image plane pixel responsive to the dimensions of the corresponding object volume shape, and the involved projection solid angle, to correct for anisotropy.

Abstract: Arbitrary interior surfaces of a three-dimensional body are displayed from a regular array of values of at least one physical property in the interior of the body. The physical property measurements may be made with systems such as computerized tomographic x-ray, or magnetic resonance imaging. Highly parallel circuits and a highly parallel architecture permit generation of surface views in real time, i.e., sufficiently fast to support ongoing procedures such as surgical operations. These parallel circuits, realizable on large scale integrated circuit chips, perform surface normal calculations, linear interpolations and signal comparisons in simultaneously operating circuit paths which are asynchronously enabled when input data appear.

Abstract: A method and apparatus for displaying arbitrary cross-sectional views of a three-dimensional body from a regular array of values of at least one physical property in the interior of the body includes making physical property measurements with such systems as computerized tomographic x-ray systems, or magnetic resonance imaging systems. Cut planes are defined by the user as displacement from, and rotations from, an arbitrary coordinate origin in the data space. An initial plane of pixel positions of arbitrary density is displaced and rotated to correspond to the cut plane. The values for the physical property at the pixel positions are interpolated from the surrounding measurements of actual values. Cross-sectional images are thereby supplied interactively in real time to support, for example, ongoing surgical procedures.

Abstract: A count is kept of the number of surfaces traversed, in a variety of three-dimensional imaging systems which are particularly advantageous for use in medical applications based upon data generated by magnetic resonance imaging systems and computerized axial tomographic imaging systems. The system is particularly advantageous in a surgical workstation for planning a wide variety of operative procedures. Surfaces may be selected and displayed simultaneously so as to provide the viewer with a significantly improved knowledge of the relationship of various internal body structures.

Abstract: A dual pipeline architecture for a system for preprocessing image data gathered from such systems as magnetic resonance imaging and computer axial tomography scanners. In one simultaneously operable dual pipeline, normal vectors are computed for each voxel element in accordance with the dividing cubes vector generation system. In another pipeline, circuitry is provided for generating surface identification indicia which are associated with unit normal vectors produced by the former pipeline. Data are supplied to a graphics processor for the production of shaded two-dimensional images representative of three-dimensional surfaces from various view angles. The system is particularly useful in medical diagnostic applications and is particularly useful in planning surgical procedures.

Abstract: An apparatus and method for determining connected substructures within a body is disclosed. The system and method are particularly advantageous for use in medical diagnostic imaging applications. In particular, three dimensional regions exhibiting the same tissue type are similarly labeled. The system and method of the present invention is operable in any situation in which three dimensional signal patterns representing the value of one or more physical properties associated with the substructures within a body at regularly spaced grid locations within the body are presented. A subset of the original data may then be provided to a display processor, particularly one employing gradient normal shading for display of three dimensional images.

Abstract: A system for displaying three dimensional surface structures employs the analysis of voxel elements defined by eight cubically adjacent grid locations which are associated with at least one physical property defined throughout a three dimensional body. The physical property measurements may be made with such systems as computerized tomographic x-ray systems, or magnetic resonance imaging devices. Surface structures are defined by a user selected threshhold value such as distinct values for skin and bone in medical diagnostic applications. Selected voxels are subdivided and means are provided for generating signal values associated with intermediate additional grid locations. Means are also provided for generating surface normal vectors associated with these grid locations.

Abstract: An apparatus for practicing temperature gradient zone melting simultaneously on a plurality of semiconductor bodies comprises a closable work chamber for receiving the bodies for processing; a heat source disposed in the work chamber and comprising a first closure member thereof; a heat sink disposed in the work chamber and comprising a second closure member thereof and means for transferring one or more bodies of semiconductor material to the work chamber for processing and from the work chamber subsequent to processing. The transferring means comprises manipulative means for selectively engaging the semiconductor bodies and supporting the bodies in transit and drive means for moving the manipulative means toward and away from the work chamber and orienting the manipulative means with respect to the semiconductor bodies.

Abstract: An apparatus for practising temperature gradient zone melting simultaneously on a plurality of semiconductor bodies comprises a closable work chamber for receiving the bodies for processing; a heat source disposed in the work chamber and comprising a first closure member thereof; a heat sink disposed in the work chamber and comprising a second closure member thereof and means for transferring one or more bodies of semiconductor material to the work chamber for processing and from the work chamber subsequent to processing. The transferring means comprises manipulative means for selectively engaging the semiconductor bodies and supporting the bodies in transit and drive means for moving the manipulative means toward and away from the work chamber and orienting the manipulative means with respect to the semiconductor bodies.