Abstract: An x-ray system is disclosed including a selector for finding an optimum combination between the contrast medium and the energy spectrum of an x-radiation for a scan to optimize the noise-to-contrast ratio. A method for creating X-ray images is also provided. The x-ray images are created with the aid of contrast media by taking into account an optimal combination between the contrast medium and the energy spectrum of an X-radiation used for a scan. A method for the use of a lanthanide-containing complex to produce a contrast medium for optimizing the combination between the contrast medium and the radiation to obtain a maximum contrast-to-noise ratio in an X-ray image is also provided.

Abstract: A method is disclosed for reconstructing CT image data. In at least one embodiment, the method includes provisioning CT projection data p. Secondly, it includes reconstruction of first image data fk=1 based on the CT projection data p. Thirdly, it includes iterative determination of k+1-th CT image data fk+1 on the basis of the first CT image data fk=1 as a function of: k-th CT image data fk, a reconstruction of differential projection data, the differential projection data being produced as the difference between reprojected CT image data fk and the CT projection data p, as well as a local contrast-dependent smoothing of the CT image data fk using a non-quadratic correction operator R(fk). Besides suppressing “cone” artifacts, the proposed method of at least one embodiment exhibits a significant reduction in image noise after just a few iterations.

Abstract: A method is disclosed for reconstructing CT image data. In at least one embodiment, the method includes providing measured CT projection data p based on the CT projection data p, reconstructing first CT image data fk=1, and on the basis of the first image data fk=1 iteratively generating k+1-th CT-image data according to the formula: fk+1=fk??(Q(Pfk?p)+?R(fk)) until the standard ?fk+1?fk?2 is ?n, with the reconstruction operator Q containing a noise weighting according to Q=B·Wstatist.·H. Aside from suppressing “cone” artifacts, the proposed method of at least one embodiment indicates a significant reduction in the image noise even after a few iterations.

Abstract: A method and a computational unit are disclosed for measuring the flow rate of a contrast agent in a vessel of a patient by way of a computed tomography examination. The patient is scanned by x-rays emitted in a fan-shape from two planes and the absorption from a multiplicity of rotational angles is determined while the contrast agent propagates through the at least one vessel. According to at least one embodiment of the invention, a three-dimensional data record of local absorption data with the vessel which can be filled by a contrast agent is reconstructed; a set of x-rays which pass through this vessel is determined for a multiplicity of temporally subsequent rotational angles of the x-rays. By determining the changing absorption values along this vessel from the temporally subsequent vessel/ray-sets, the propagation velocity of the contrast agent in this vessel can be determined from the spatial and temporal change in the absorption values in this vessel.

Abstract: An x-ray system is disclosed including a selector for finding an optimum combination between the contrast medium and the energy spectrum of an x-radiation for a scan to optimize the noise-to-contrast ratio. A method for creating X-ray images is also provided. The x-ray images are created with the aid of contrast media by taking into account an optimal combination between the contrast medium and the energy spectrum of an X-radiation used for a scan. A method for the use of a lanthanide-containing complex to produce a contrast medium for optimizing the combination between the contrast medium and the radiation to obtain a maximum contrast-to-noise ratio in an X-ray image is also provided.

Abstract: A method and a device are disclosed for automatically differentiating bones or other calcium-containing materials and contrast agent in soft tissue of an object area. In at least one embodiment of the method, two image data records of two computed tomography pictures of the object are provided that have been recorded in the context of a different spectral distribution of the X-radiation. For voxels of at least one interesting slice, there is calculated from the two image data records a ratio r that is yielded from measured or averaged X-ray attenuation values of the respective voxel or its environment in the context of the different spectral distributions of the X-radiation and prescribed X-ray attenuation values of soft tissue in the context of the different spectral distributions of the X-radiation according to a prescribed calculation rule.

Abstract: At least one embodiment of the present application relates to a method and/or an apparatus for determining the concentration of a substance in a body material that is composed of two different material components in an unknown ratio. In an embodiment of the method, two computed tomography pictures from which two image data records are reconstructed are recorded in conjunction with two different spectral distributions of the x-radiation. The x-ray attenuation values for each voxel of the two image data records are decomposed into three material components. The decomposition is performed on the assumption that the x-ray attenuation value xM of the body material without the substance is composed of the x-ray attenuation values xM1, xM2 of the first and second material component in accordance with the following equation: xM=f*xM1+(1-f)*XM2, f being a volume fraction of the first material component in the body material.

Abstract: A method is disclosed for generating CT displays in x-ray computed tomography with contrast medium support, the blooming effect being reduced by decomposing an object into three material components when scanning the object with two different energy spectra, and determining a first component and determining the material thickness thereof by segmentation. Subsequently, in at least one embodiment, the two other material components and their material thicknesses are determined on the basis of the measured attenuation values of the two spectra for each beam, and virtual absorption data with virtual absorption coefficients are constructed for the individual material components from the material strengths thus known for the different material components, and are used to reconstruct the CT display.

Abstract: A filter method for tomographic 3D displays is disclosed, in which a volume model is used for display, which reproduces the volume of the examination object in the form of a large number of three-dimensional image voxels, and the image value of each voxel reproduces one object-specific characteristic of the examination object in this volume. According to the method, the original image voxels are processed using a 2D filter which is the same over the entire image area, and two different linear filters with selected directions which are obtained from the extremes of the previously calculated variances thus resulting in three data records with differently filtered image voxels, and in which, furthermore, the original image voxels and the filtered image voxels are mixed using local weights to form a result image.

Abstract: A method is for determining a parameter in an image area as a measure of a homogeneity of a substance in an object, and to a method for segmenting a substance in an image that uses the parameter as an additional segmentation criterion. In the method, at least two X-ray images are acquired in relation to different energies E1, E2 of an X-radiation, and the parameter is determined from the statistical distribution of attenuation values Di(E1),Di(E2) where i=1, . . . , N in the image area such that faulty classifications can be avoided in a simple way during the segmentation.

Abstract: A method is disclosed for calculating absorber-specific weighting coefficients and a method is disclosed for improving a contrast-to-noise ratio, dependent on an absorber, in an x-ray image of an object to be examined produced by an x-ray machine. A weighted summation of detector output signals from different energy windows of an energy-selector detector are used to improve the contrast-to-noise ratio as a function of the absorber.