Abstract: A system and method for decomposing more than two materials in an imaging object includes performing a CT imaging acquisition of a portion of an imaging object using at least two energy levels to acquire imaging data associated with each of the at least two energy levels. A total mass attenuation of the imaging data is expressed as a weighted sum of constituent element mass attenuation coefficients and an effective atomic number and density of the constituent elements in the portion of the imaging object is determined by one of a number of methods. Accordingly, concentration of the constituent elements in imaged object is determined by solve the expression using known material attenuation coefficients and the measured CT data.

Abstract: The present invention is a method for reducing artifacts caused by highly attenuating materials in x-ray computed tomography (“CT”) images. The method includes combining projection views acquired at equivalent view angles to generate a projection plane data set, from which a reformatted projection is produced. The reformatted projection is then processed to detect and segment regions corresponding to objects composed of metals, metal alloys, or other highly attenuating materials. These segmented regions are then removed from the reformatted projection and the removed portions replaced by attenuation information interpolated from portions of the reformatted projection adjacent the removed portions. The interpolated reformatted projection is then mapped back to a projection plane data set, and an image of the subject is reconstructed from the projection views contained in that data set.

Abstract: A method for CT imaging that utilizes an automatic tube potential selection for individual subjects and diagnostic tasks. The method quantifies the relative radiation dose of different tube potentials for achieving a specific image quality. This allows the selection of a tube potential that provides a reduced radiation dose while still providing CT images of a sufficient quality.

Abstract: Methods, systems, and apparatuses for non-convex prior image constrained compressed sensing are disclosed. In one embodiment, a method is provided for iterative image reconstruction for medical imaging applications which employ a prior image to constrain the reconstruction process allowing the use of fewer high SNR samples or complete but lower SNR samples. The objective function made use of non-convex compressed sensing methods during the iterative reconstruction process. Applications include, but are not limited to radiation dose reduction and fast image acquisition.

Abstract: A system and method for the accurate quantitative evaluation of dual-energy computed tomography (CT) projection data that is acquired in a dual-source helical scan includes employing a dual-source z-axis helical interpolation method. The method includes transforming the two helical projection data sets, where corresponding projections of high- and low-energy data sets are shifted with respect to one another by 90 degrees or another angle, into corresponding non-helical projection data sets. A dual-source helical interpolation algorithm allows for projection space dual-energy processing by realigning the high- and low-energy datasets based on the z-axis interpolation. This algorithm may be implemented using a variety of interpolation schemes and can be extended from single slice to multi-slice data acquisitions.

Abstract: The present invention provides a material decomposition method capable of determining the distribution of density and constituent material concentration throughout an imaged object. The concentration, in the form of a mass fraction, mass percent, weight fraction, or weight percent, is determined from CT images acquired at different energy levels. The ratio of attenuation coefficients associated with one energy level to attenuation coefficients associated with another energy level is determined and used as an index in a lookup table to determine the concentration of a given material throughout the imaged object.

Abstract: Contrast from dual energy CT images is removed without affecting other aspects of the image, including objects surrounded by contrast. Dual energy images are acquired during a study of a subject. First, a binary mask image (“Contrast localizer”) is produced to localize the contrast-enhanced areas and build sets of images with contrast-enhanced areas only (“Contrast images”) and complement images with contrast-enhanced areas removed (“Contrast complement images”) for both low and high x-ray beam energy image sets. Only the contrast images are used for dual energy contrast subtraction. Second binary mask image (“Subject localizer”) is produced to localize the objects under study. This mask image is used to reconstruct both low and high energy image sets with contrast selectively removed and subject present.

Abstract: A system and method for creating a combined or mixed-energy image using both low- and high-energy CT data sets acquired using a dual-energy CT system. The low- and high-energy datasets are mixed using desired weighting factors to mimic a “single-energy” image. The low-energy dataset provides data with improved contrast enhancement, but with increased noise level. The high-energy dataset provides data with lower contrast enhancement, but with better noise properties. By combining the low- and high-energy datasets in accordance with the present method, the resulting mixed-energy images utilize the information of full dose of radiation used in the dual-energy scan. A plurality of weighting metrics can be selected, including patient size, dose partitioning, or image quality, to determine the desired weighting factors based on the weighting metrics. By selecting the proper weight factors, image noise can be reduced and/or the contrast to noise ratio can be increased in the mixed-energy image.

Abstract: The present invention is a method for reducing artifacts caused by highly attenuating materials in x-ray computed tomography (“CT”) images. The method includes combining projection views acquired at equivalent view angles to generate a projection plane data set, from which a reformatted projection is produced. The reformatted projection is then processed to detect and segment regions corresponding to objects composed of metals, metal alloys, or other highly attenuating materials. These segmented regions are then removed from the reformatted projection and the removed portions replaced by attenuation information interpolated from portions of the reformatted projection adjacent the removed portions. The interpolated reformatted projection is then mapped back to a projection plane data set, and an image of the subject is reconstructed from the projection views contained in that data set.

Abstract: A method for temporally imaging a cyclic body structure during a predetermined phase of its cycle using a CT scanner of the type having a rotating radiation source. In one embodiment the image or other display is generated using data produced when the radiation source is at a predetermined position when the body structure is in the predetermined phase. The method can be performed by using only data collected when the radiation source is at the predetermined position and the body structure is in the predetermined phase, by stimulating the body structure so the phase of the body structure and location of the radiation source are synchronized, or by controlling the motion of the radiation source so the location of the radiation source and the phase of the body structure are synchronized.

Abstract: The present invention provides a material decomposition method capable of determining the distribution of density and constituent material concentration throughout an imaged object. The concentration, in the form of a mass fraction, mass percent, weight fraction, or weight percent, is determined from CT images acquired at different energy levels. The ratio of attenuation coefficients associated with one energy level to attenuation coefficients associated with another energy level is determined and used as an index in a lookup table to determine the concentration of a given material throughout the imaged object.

Abstract: A system and method for decomposing more than two materials in an imaging object includes performing a CT imaging acquisition of a portion of an imaging object using at least two energy levels to acquire imaging data associated with each of the at least two energy levels. A total mass attenuation of the imaging data is expressed as a weighted sum of constituent element mass attenuation coefficients and an effective atomic number and density of the constituent elements in the portion of the imaging object is determined by one of a number of methods. Accordingly, concentration of the constituent elements in imaged object is determined by solve the expression using known material attenuation coefficients and the measured CT data.

Abstract: A system and method for creating a combined or mixed-energy image using both low- and high-energy CT data sets acquired using a dual-energy CT system. The low- and high-energy datasets are mixed using desired weighting factors to mimic a “single-energy” image. The low-energy dataset provides data with improved contrast enhancement, but with increased noise level. The high-energy dataset provides data with lower contrast enhancement, but with better noise properties. By combining the low- and high-energy datasets in accordance with the present method, the resulting mixed-energy images utilize the information of full dose of radiation used in the dual-energy scan. A plurality of weighting metrics can be selected, including patient size, dose partitioning, or image quality, to determine the desired weighting factors based on the weighting metrics. By selecting the proper weight factors, image noise can be reduced and/or the contrast to noise ratio can be increased in the mixed-energy image.