Abstract: A three-dimensional projection image representing a projection of a data volume at a predetermined orientation, three cut plane images representing respective mutually orthogonal planar cuts through the data volume, a graphical representation of the data volume at that orientation and graphical representations of the cut planes are displayed in spaced relationship. Each of the cut planes has a respective positional relationship to the data volume graphic that corresponds to the positional relationship of the respective cut plane to the data volume. The graphical representations are displayed in different colors. Any one of the four images can be active in the sense that images are reconstructed in real-time as a trackball is moved. Which of the four images is active is indicated by displaying the corresponding graphical representation in a color denoting the active state.

Abstract: A method and an apparatus for segmenting three-dimensional projected velocity images by limiting the volume of velocity data projected onto the imaging planes. If the volume of interest contains flowing blood, i.e., an artery or vein, the Doppler shift present in the ultrasound reflected from the flowing blood can be detected and then used to limit the amount of velocity data which is projected. Only pixels having velocity values within a predetermined range are projected onto the imaging plane.

Abstract: A method and apparatus for calculating the inter-slice spacing in a data volume and registering the slices of that volume using SAD calculations. The resulting transformed data volume is then three-dimensionally reconstructed using a projection technique. If during scanning the probe is translated in the Z direction and at the same time is shifted in the X and/or Y direction, the SAD value will be artificially high. By translating two adjacent images with respect to each other in the X direction and then in the Y direction, and searching for the minimum SAD value, the amount of shift in the X and/or Y direction can be determined and that shift can then be removed. Also by rotating two slices with respect to each other and looking for a minimum SAD value, rotational motion of the probe during scanning can be removed.

Abstract: In performing for three-dimensional ultrasound imaging of an object from any angle relative to the plane of acquisition, a human body is scanned to acquire multiple images forming a data volume. The system computer generates a multiplicity of reformatted slices through the data volume and parallel to the imaging plane. For each projected pixel, a ray is cast through the reformatted slices onto the imaging plane. For each pixel along the ray, the accumulated intensity is calculated as a function of the pixel and opacity values for the pixel being processed, the accumulated intensity calculated at the preceding pixel the remaining opacity for the subsequent pixels. The final accumulated intensity for each ray is obtained when the remaining opacity reaches a predetermined minimum. The accumulated intensities for all cast rays form the projected image.

Abstract: A three-dimensional image of flowing fluid or moving tissue using velocity or power Doppler data is displayed by using an ultrasound scanner that collects velocity or power data in a cine memory to form a volume of pixel data. Average or median pixel values are projected on an image plane by casting rays through the data volume. As the ray passes through each scan plane, a data value is assigned to the ray at that point. At each scan plane, the assigned pixel data value is tested to see if it exceeds a noise threshold. For a given ray, pixel data values above the detection threshold are accumulated until a pixel data value falls below the detection threshold. A minimum number of pixel data values exceeding the threshold are required for each ray before the average of the accumulated values is processed and/or the median value is selected. When all pixels along a given ray have been tested, the projection is complete and the average or median projection is then displayed.

Abstract: A method and an apparatus for three-dimensional ultrasound imaging of a needle-like instrument, such as a biopsy needle, inserted in a human body. The instrument is visualized by transmitting ultrasound beams toward the instrument and then detecting the echo signals using a linear array of transducer elements. The problem of ultrasound being reflected from a biopsy needle in a direction away from the transducer array is solved by steering the transmitted ultrasound beams to increase the angle at which the beams impinge upon the biopsy needle. Ideally the ultrasound beams are perpendicular to the biopsy needle. This increases the system's sensitivity to the needle because the reflections from the needle are directed closer to the transducer array. This can be accomplished using either the B mode or the color flow mode of an ultrasound imaging system.

Abstract: A method and an apparatus for allowing the operator of an ultrasound imaging system to switch between two-dimensional slices and three-dimensional projections in such a way that it is easy for the operator to visualize the relationship of the two-dimensional slice to the three-dimensional anatomy. In a "volume rotate" mode, the display screen displays an orientation box along with a three-dimensional projected image generated from a defined data volume. The orientation box provides a visual indication of the shape and orientation of that defined data volume. In a "cut plane" mode, a movable polygon representing a selected two-dimensional slice is displayed inside a stationary orientation box. The polygon provides a visual indication of the orientation and position of the slice relative to the defined data volume. In a "cut plane rotate" mode, a stationary polygon representing a selected two-dimensional slice is displayed inside a rotatable orientation box.

Abstract: A method and an apparatus for three-dimensional imaging of ultrasound data by combining projections of intensity data with projections of velocity or power data from a volume of interest. The apparatus is an ultrasound scanner which collects B-mode or color flow images in a cine memory, i.e., for a multiplicity of slices. The data from a respective region of interest for each slice is sent to a master controller, such data forming a volume of interest. The master controller performs an algorithm that projects the data in the volume of interest on a plurality of rotated image planes using a ray-casting technique. The combined intensity and velocity or power data for each projection is stored in a separate frame in the cine memory. These reconstructed frames are then displayed selectively by the system operator.

Abstract: A method and an apparatus for improving the segmentation of a three-dimensional B-mode image by limiting the volume of pixel intensity data projected onto the imaging planes. If the volume of interest contains moving ultrasound scatterers, e.g., blood flowing in an artery or vein, the Doppler shift present in the ultrasound reflected from the flowing blood can be detected and then used to limit the amount of pixel data which is projected. The velocity or power data is used to identify those intensity values to be projected onto the imaging plane. This is accomplished by locating a reference data volume of pixels for which the velocity or power value is non-zero and then defining a source data volume which is essentially a function of that reference data volume. The reference data volume comprises pixels acquired from echo return signals reflected by the moving ultrasound scatterers.

Abstract: A method and an apparatus for three-dimensional imaging of ultrasound data by constructing projections of data from a volume of interest. An ultrasound scanner collects B-mode or color flow images in a cine memory, i.e., for a multiplicity of slices. A multi-row transducer array having a uniform elevation beamwidth is used to provide reduced slice thickness. The data from a respective region of interest for each of a multiplicity of stored slices is sent to a master controller, such data forming a volume of interest. The master controller performs an algorithm that projects the data in the volume of interest onto a plurality of rotated image planes using a ray-casting technique. The data for each projection is stored in a separate frame in the cine memory. These reconstructed frames are then displayed selectively by the system operator. Segmentation of three-dimensional projection images is enhanced by decreasing the thickness and increasing the resolution (i.e.

Abstract: A method and an apparatus for three-dimensional imaging of ultrasound data by constructing projections of data from a volume of interest. An ultrasound scanner collects B-mode or color flow images in a cine memory, i.e., for a multiplicity of slices. A multi-row transducer array having a uniform elevation beamwidth is used to provide reduced slice thickness. In particular, the multi-row transducer array has a central row made up of elements having an area smaller than the combined area of the paired elements of two outermost rows The data from a respective region of interest for each of a multiplicity of stored slices is sent to a master controller, such data forming a volume of interest. The master controller performs an algorithm that projects the data in the volume of interest onto a plurality of rotated image planes using a ray-casting technique. The data for each projection is stored in a separate frame in the cine memory. These reconstructed frames are then displayed selectively by the system operator.