Abstract: In a device and associated method for reconstruction and visualization of projection data, projection data are stored per slice and are subjected to an image reconstruction procedure in parallel within arbitrary slice planes in a processor-controlled filtering process that is executed n times, wherein volume data that are created can already be made available (loaded) for a direct visualization.

Abstract: In a computer tomography method an object region of the object being examined is determined in that projection beams that are linked with maximum attenuation are sought in cropped projection images. A central point of the object region is then determined and the object sections associated with the projection beams plotted on the central point. The object region can be at least approximately determined using the end points of the object sections.

Abstract: Method for three-dimensional representation of arteries and/or veins in an object by a tomography x-ray device is proposed. A mask pass with N projections at N angular positions without contrast agent is implemented. A first filler pass with M projections at M angular positions after injecting a contrast agent, where M<N is implemented, followed by a second filler pass with N?M projections at N?M angular positions. A composite three-dimensional volume data record is reconstructed from an intermediate data record determined from the mask pass, the first and the second filler pass. A reprojection for arteries and/or for veins is calculated by reprojection of the first filler pass and/or of the second filler pass from the composite three-dimensional volume data record. A three-dimensional volume data record for arteries and/or for veins is calculated by weighting the composite three-dimensional volume data record taking into account the respective measured and calculated projection images.

Abstract: The invention relates to a method for reducing image noise in the context of capturing at least one radiation-based image of a region of interest using two different radiation spectra, in particular two different x-ray radiation spectra, comprising the following steps: capturing raw images of the region of interest using the two different radiation spectra with in each case mutually paired measured values; and to separate different materials in the region of interest, applying to the captured raw images at least one inversion operator with integrated noise filtering, said operator describing a transition from a measured value pair to an assigned reconstruction value pair.

Abstract: A method for creating material-selective volume images of various material components of an object to be examined is proposed. The method is based on multi-spectral projected images captured from various directions of projection, the images being captured using an X-ray machine, and makes it possible to quantitively exactly determine the material-selective volume images by way of iteration.

Abstract: A number of two-dimensional projection images of a three-dimensional examination object are assigned image times and imaging parameters. The projection images are combined into reconstruction groups including projection images with image times specifically assigned or within a time interval specific to the reconstruction groups. The reconstruction groups are determined in such a way that three-dimensional reconstructions of the examination object with direction-dependent local resolution can be determined based on the projection images of the reconstruction groups; it is not possible to determine three-dimensional reconstructions of the examination object with direction-independent local resolution. Three-dimensional reconstructions of the examination are determined based on the projection images of the reconstruction groups. Reconstruction times are determined based on the image times assigned to the projection images of the reconstruction groups and assigned to the three-dimensional reconstructions.

Abstract: The invention relates to a computed tomography method. The airgap associated with a projection direction is determined by determining, in the projection images, edge pixels which map object edges on a detector. By back-projecting the edge pixels in an object image space it is possible to determine an envelope polygon for an outline contour of the examination object. The width of the airgap associated with a specific projection direction can then be determined on the basis of the envelope polygon. Exact knowledge of the current airgap serves to improve the scattered radiation correction.

Abstract: The invention relates to a method for a three-dimensional representation of a moving structure by a tomographic method, in which during one recording pass a series of projection recordings is registered by an imaging unit at different recording angles between a start position and an end position, it being possible to reconstruct three-dimensional image data from the projection recordings with the following steps: a) generation of tomosynthesis projection recordings along a tomosynthesis scanning path; b) interpolation of the data of the tomosynthesis projection recordings in accordance with an interpolation algorithm in order to generate a projection data set; c) use of a tomosynthesis reconstruction method on the projection data set in order to generate a tomosynthesis volume image; d) repetition of steps b) and c) for all times of interest, and e) display of tomosynthesis representations from the tomosynthesis volume images.

Abstract: In a method for correction of scatter radiation errors in radiography and computer tomography, using flat panel detectors, initially an estimation of a scatter radiation distribution Scor(y,z) is undertaken, and a standard correction term ?pcor is subsequently calculated. Noise filtering of the standard correction term ?pcor with F(?pcor) is implemented and subsequently the noise-filtered standard correction term F(?pcor) is added to the logarithmized measured total projection data ps. The noise filtering can be implemented adaptively dependent on a previously-determined local noise variance. The method can be implemented in a radiography system and/or by a computer for generation and/or processing of projective and/or tomographic exposures, with a memory containing program codes causing the computer in operation to execute the steps of the method.

Abstract: In a known type of tomosynthesis x-ray source and x-ray detector are linearly moved and x-rays images are taken for a large number of positions, the images being reconstructed to give a 3D image record. According to the invention x-ray source and x-ray detector are swiveled and a sequence of x-rays is subsequently taken again, x-ray source and x-ray detector again being moved in a straight line. One drawback of simple tomosynthesis with movement in a straight line is suppressed thereby, the drawback being that the quality of reconstruction is particularly poor in a certain direction.

Abstract: In a device and associated method for reconstruction and visualization of projection data, projection data are stored per slice and are subjected to an image reconstruction procedure in parallel within arbitrary slice planes in a processor-controlled filtering process that is executed n times, wherein volume data that are created can already be made available (loaded) for a direct visualization.

Abstract: The invention relates to a method for generating tomographical recordings of a partially cyclically moving examination object by a tomography system and a tomography system, comprising the steps of: a spatial scanning of the examination object taking place using at least one detector, which generates detector output data; movement information of the moving subarea of the examination object being recorded during the scanning and being assigned to the detector output data or stored in a manner which correlates to the detector output data; and tomographical image data being reconstructed from the measured detector output data in a number of iteration steps. The invention is characterized in that iteration takes place in at least two iteration stages, with data records being used from the detector output data of different cycle phase regions in at least two iteration stages.

Abstract: In a tomosynthetic image reconstruction method and diagnostic device operating with such a method, a tomosynthetic 3D x-ray image is reconstructed by a discrete filtered back projection from a number of individual digital projection data recorded from different project angles within a restricted angular range, in which at least one filtering is performed with a convolution kernel that, in the local area outside of its central value, corresponds to an exponential function.

Abstract: A method for creating material-selective volume images of various material components of an object to be examined is proposed. The method is based on multi-spectral projected images captured from various directions of projection, the images being captured using an X-ray machine, and makes it possible to quantitively exactly determine the material-selective volume images by way of iteration.

Abstract: In a method for correction of scatter radiation errors in radiography and computer tomography, using flat panel detectors, initially an estimation of a scatter radiation distribution Scor(y,z) is undertaken, and a standard correction term ?pcor is subsequently calculated. Noise filtering of the standard correction term ?pcor with F(?pcor) is implemented and subsequently the noise-filtered standard correction term F(?pcor) is added to the logarithmized measured total projection data ps. The noise filtering can be implemented adaptively dependent on a previously-determined local noise variance. The method can be implemented in a radiography system and/or by a computer for generation and/or processing of projective and/or tomographic exposures, with a memory containing program codes causing the computer in operation to execute the steps of the method.

Abstract: In a tomosynthetic image reconstruction method and diagnostic device operating with such a method, a tomosynthetic 3D x-ray image is reconstructed by a discrete filtered back projection from a number of individual digital projection data recorded from different project angles within a restricted angular range, in which at least one filtering is performed with a convolution kernel that, in the local area outside of its central value, corresponds to an exponential function.

Abstract: In a method and MRI apparatus for the minimization of streak artifacts in modular k-space scanning in magnetic resonance imaging, an odd integer k-space scanning module number N?=2n+1 is defined that defines the number of incrementally rotated repeated modules of the k-space scanning process, a slice selection gradient selects any slice in the range of the object to be examined, and data for all N? angle-oriented k-space scanning modules in the selected slice acquired such that each k-space scanning module has an azmuthal distance of ? ? ? ? 2 = 360 ? ° 2 ? ? N ? from both adjacent projections, with the direction of the scanning of the adjacent k-space scanning modules alternating.

Abstract: In a method for reconstruction of a three-dimensional image of an object scanned in linear or circular fashion in the context of a tomosynthesis. The object is transirradiated with X-rays from various projection angles &phgr; for the recording of the projection images, and the radiation exiting from the object is recorded by a detector that supplies digital output image signals. The output image signals representing the projection image data are supplied to a computer for image reconstruction. In the context of the reconstruction a filter is first produced, on the basis of the following steps: A 3D transmission function Hproj(&ohgr;x,&ohgr;y,&ohgr;z) is calculated from the recording geometry for the individual projection image recording and the back-projection of the individual projection images into the 3D reconstruction image volume. By approximation, the 3D transmission function Hproj(&ohgr;x,&ohgr;y,&ohgr;z) is inverted for the determination of an inversion function Hinv(&ohgr;x,&ohgr;y,&ohgr;z).

Abstract: In an x-ray diagnostic apparatus for tomosynthesis or laminographic imaging using a patient positioning table, an x-ray source which emits an x-ray beam on one side of the patient positioning table, an x-ray detector arranged on the other side of the patient positioning table for the capture of the x-ray beam and for producing digital images, a device for movement of the x-ray source, a device for shifting of the x-ray detector and a device for superimposing the digital images so that only the details lying in a specific longitudinal slice for an examination subject are sharply imaged, the x-ray detector is rotated relative to the movement direction at an angle.

Abstract: A sectional plane of the examination subject is first scanned by focused ultrasound transmission beams in an adaptation phase. Disturbing effects from the reflected echo signals which are caused by the inhomogenities in the tissue are thereby measured. In this adaptation phase, correction values for the delay time of the signals of the elemental transducers of the ultrasound array in comparison to the standard focusing are also derived from the measured values. In a following B-image imaging phase, the delay times of the active aperture are then varied dependent on the correction values during the emission and/or during reception. The disturbing effects are thereby compensated. A method and apparatus are disclosed which are especially well-suited for linear array systems and for patients having inhomogeneous tissues.