Abstract: The current invention is generally related to a data acquisition and or image processing method and system for acquiring and or processing sparse channel data. The sparse channel is implemented in a data acquisition system having a predetermined wider pitch between the adjacent detector cells than that in the currently available imaging systems at least in one predetermined channel direction. The sparse channel is also defined to encompass various imaging modalities including CT, positron emission tomography (PET) and positron emission tomography-computed tomography (PET/CT). The sparse channel data is acquired by the sparse channel data acquisition system, and an image is reconstructed from the sparse channel data according to a predetermined iterative reconstruction technique.

Abstract: Photon starvation causes streaks and noise and seriously impairs the diagnostic value of the CT imaging. To reduce streaks and noise, a new scheme of adaptive Gaussian filtering relies on the diffusion-derived scale-space concept in one embodiment of the current invention. In scale-space view, filtering by Gaussians of different sizes is similar to decompose the data into a sequence of scales. As the scale measure, the variance of the filter linearly relates to the noise standard deviation of a predetermined noise model in the new filtering method. The new filter has only one optional parameter that remains stable once tuned. Although single-pass processing using the new filter generally achieves desired results, iterations are optionally performed.

Abstract: A computed tomography apparatus and method using line data estimated from circle data and scanogram data. An image of a subject is reconstructed using the circle data and the estimated line data. The circle data and scanogram data may be weighted in estimating the line data. The apparatus and method are useful in diminishing or eliminating streak artifacts in reconstructed images such as images including the spine.

Abstract: A method of reconstructing a volume image of an object includes receiving circle projection data collected by a detector along a circular path with respect to the object; receiving line projection data collected by the detector along a linear path with respect to the object; producing a reconstructed circle path volume image of the object from the pre-processed circle projection data using a reconstruction algorithm that includes a ramp filter; producing a reconstructed line path volume image of the object from pre-processed line projection data using a reconstruction algorithm that includes a Hubert filter; and combining the reconstructed circle path volume image and the reconstructed line path volume image to produce the volume image of the object. An apparatus and computer program product are also described.

Abstract: A method of obtaining a computed tomography image of an object includes determining linear terms and non-linear beam hardening terms in a pair of line integral equations for dual-energy projection data from inserting average and difference from average attenuation terms, obtaining an initial solution of the line integral equation by setting the non-linear beam hardening terms to zero, and iteratively solving the line integral equations to obtain one line integral equations for each basis material. Attenuation by the first basis material corresponds to a photoelectric attenuation process, and attenuation by the second basis material corresponds to a Compton attenuation process. The line integral equations can be inverted by an inverse Radon procedure such as filtered backprojection to give images of each basis material. The images of each basis material can then be optionally combined to give monochromatic images, density and effective atomic number images, or photoelectric and Compton processes images.

Abstract: The CT imaging system optimizes its image generation by adaptively weighting certain parameters during the iterations in an iterative reconstruction algorithm. The projection data is grouped into N subsets, and after each of the N subsets is processed by the ordered subsets simultaneous algebraic reconstruction technique (OSSART), the image undergoes total variation (TV) minimization process. During the iterative reconstruction algorithm, a combination of the parameters such as a total variation, a relaxation parameter and a step size parameter is assigned a respective value based upon the current value of the iteration.

Abstract: Embodiments and processes of computer tomography perform tasks associated with denoising a reconstructed image using an anistropic diffusion filter and adaptively weighting an iterative instance of the diffused image based upon the product of a weight value and a difference between the iterative instance of the diffused image and the original image. In general, the adaptive weighting is a negative feedback in the iterative steps.

Abstract: A computed tomography apparatus and method using line data estimated from circle data and scanogram data. An image of a subject is reconstructed using the circle data and the estimated line data. The circle data and scanogram data may be weighted in estimating the line data. The apparatus and method are useful in diminishing or eliminating streak artifacts in reconstructed images such as images including the spine.

Abstract: A three dimensional image processing apparatus includes a feature point designation unit which designates feature points on at least two selected images selected from a plurality of images in different radiographing directions, a three dimensional position calculation unit which calculates a three dimensional position associated with a feature point, a two dimensional position calculation unit which calculates the two dimensional position of a feature point on an unselected image on the basis of the calculated three dimensional position of the feature point, a feature point extraction unit which extracts a feature point from an unselected image, a positional shift calculation unit which calculates a positional shift of the two dimensional position of the extracted feature point with respect to the calculated two dimensional position of the feature point, and a correction unit which corrects the position of the unselected image on the basis of the calculated positional shift.

Abstract: Scattered radiation is estimated by using a reduced image generated from a projection image, and the scattered radiation image of the projection image is acquired by enlargement processing. The scattered radiation correction of the projection image is executed by subtracting the obtained scattered radiation image from the projection image. In addition, when a primary X-ray image and a scattered radiation image in each projection direction are to be obtained by sequential approximation calculation, a primary X-ray image which has already been identified in an adjacent projection direction is used as a first estimated value (initially set value) in next sequential calculation.

Abstract: A method of reconstructing a volume image of an object includes receiving circle projection data collected by a detector along a circular path with respect to the object; receiving line projection data collected by the detector along a linear path with respect to the object; producing a reconstructed circle path volume image of the object from the pre-processed circle projection data using a reconstruction algorithm that includes a ramp filter; producing a reconstructed line path volume image of the object from pre-processed line projection data using a reconstruction algorithm that includes a Hubert filter; and combining the reconstructed circle path volume image and the reconstructed line path volume image to produce the volume image of the object. An apparatus and computer program product are also described.

Abstract: Scattered radiation is estimated by using a reduced image generated from a projection image, and the scattered radiation image of the projection image is acquired by enlargement processing. The scattered radiation correction of the projection image is executed by subtracting the obtained scattered radiation image from the projection image. In addition, when a primary X-ray image and a scattered radiation image in each projection direction are to be obtained by sequential approximation calculation, a primary X-ray image which has already been identified in an adjacent projection direction is used as a first estimated value (initially set value) in next sequential calculation.

Abstract: A three dimensional image processing apparatus includes a storage unit storing data of images in different radiographing directions together with information concerning cardiac phases, a key image selection unit selecting key images from the images, a feature point designation unit designatting feature points on the selected key images in accordance with operation by an operator, and an image reconstruction unit reconstructing a three dimensional image from the images on the basis of positions of the designated feature points, wherein the key image selection unit selects, as the key images, a pair of images which are located at the same cardiac phase and whose radiographing directions are different by a substantially predetermined angle and images spaced apart from each other by an angle obtained by substantially equally dividing an interval between the pair of images by a predetermined number.

Abstract: A method of removing an imaging artifact in a medical image, including obtaining a first plurality of images, the first plurality of images collectively defining a first image volume; filtering the first plurality of images to create a second plurality of images, each image in the second plurality of images comprising an average of at least two images in the first plurality of images; selecting a first image from the first plurality of images; adding a lost noise image to a second image in the second plurality of images to create a noise restored image, the second image in the second plurality of images corresponding to the first image in the first plurality of images; determining a gradient image based on pixel values in the second plurality of images, the gradient image comprising a gradient value at each pixel location in the second image; and combining, based on the determined gradient image, the first image and the noise restored image to obtain a corrected image that does not contain the imaging artifac

Abstract: A method of obtaining a computed tomography image of an object includes determining linear terms and non-linear beam hardening terms in a pair of line integral equations for dual-energy projection data from inserting average and difference from average attenuation terms, obtaining an initial solution of the line integral equation by setting the non-linear beam hardening terms to zero, and iteratively solving the line integral equations to obtain one line integral equations for each basis material. Attenuation by the first basis material corresponds to a photoelectric attenuation process, and attenuation by the second basis material corresponds to a Compton attenuation process. The line integral equations can be inverted by an inverse Radon procedure such as filtered backprojection to give images of each basis material. The images of each basis material can then be optionally combined to give monochromatic images, density and effective atomic number images, or photoelectric and Compton processes images.

Abstract: A computed tomography apparatus and method using line data estimated from circle data and scanogram data. An image of a subject is reconstructed using the circle data and the estimated line data. The circle data and scanogram data may be weighted in estimating the line data. The apparatus and method are useful in diminishing or eliminating streak artifacts in reconstructed images such as images including the spine.

Abstract: A computed tomography apparatus and method where data is upsampled with shifting to produce upsampled data. The data is shifted up and down in the same amount in the z-direction, and then upsampled through interpolation. An image is reconstructed using the upsampled data. The process is preferably performed column-by-column. An upsampling shift and interpolation kernel size can be adaptive to the data z-gradient.

Abstract: A three dimensional image processing apparatus includes a storage unit storing data of images in different radiographing directions together with information concerning cardiac phases, a key image selection unit selecting key images from the images, a feature point designation unit designatting feature points on the selected key images in accordance with operation by an operator, and an image reconstruction unit reconstructing a three dimensional image from the images on the basis of positions of the designated feature points, wherein the key image selection unit selects, as the key images, a pair of images which are located at the same cardiac phase and whose radiographing directions are different by a substantially predetermined angle and images spaced apart from each other by an angle obtained by substantially equally dividing an interval between the pair of images by a predetermined number.

Abstract: A method, system, and computer program product for compensating for the unavailability of projection data of a scanned object at a selected point, the selected point located outside a detection range of a detector. The method include the steps of obtaining projection data of the scanned object, and compensating for the unavailability of the projection data at the selected point based on the obtained projection data and coordinates of the selected point relative to the detector. The compensating step includes determining at least one complementary projection angle and coordinates of at least one complementary point based on a source projection angle and the coordinates of the selected point relative to the detector, and estimating the projection data value at the selected point based on the acquired projection data, the at least one complementary projection angle, and the coordinates of the at least one complementary point.

Abstract: A method and system for reconstructing an x-ray image from a partial orbit through the use of a “virtual” fan angle. The virtual fan angle is determined based upon the range of angular positions spanned by a source in a CT instrument or a selected smaller angle. Exposure data is obtained and he virtual fan angle is used to weight the exposure data. Image reconstruction can then proceed using the weighted exposure data. The described methods and system also function for data collected over a complete orbit.