Abstract: A method is disclosed for the production of CT images via a CT spiral reconstruction of object for examination moving in partial areas in a cyclical manner and a CT device therefor. During scanning of the object to be examined, various rates of advancement are used, irrespective of whether the scanned area is at least partially cyclically displaced or is stationary.

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: In a method and device for, generating computed tomography images of a periodically moving organ of an organism, the organ having regions with rest phases and movement phases and the rest phases of different regions ensuing at different points in time, an x-ray source is moved around the body of the organism to be examined to generate projections serving for the image generation during at least one rotation of the x-ray source around the subject to be examined and during a duration that is at least equal to a period of the motion. The projection data are analyzed as to whether the data were acquired during a rest phase or movement phase of a respective region of interest of the organ, and an image of the organ is reconstructed using only data acquired during a rest phase of a respective region of interest of the organ.

Abstract: A method and a CT unit are proposed for producing CT images of an examination object having a periodically moving subregion, preferably a beating heart, by multi-planar reconstruction. Subsequent to joining the axial images with pixels from a number of partial volumes calculated for the rest phases, a reduction takes place to reduce artifacts occurring in overlap regions. This is done by carrying out threshold value formation in the zone of the boundary regions of the partial volumes with result image Dz. A pixel-oriented median filtering then occurs, resulting in image Mz. A differential value image is then produced using Fz=Dz?Mz. Subsequently, two-dimensional lowpass filtering is applied to Fz to produce a result image Gz. Finally, a calculation of Bz?Gz is used to form the final image Ez.

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 disclosed for compiling computer tomographic representations using a CT system with at least two angularly offset ray sources. A first ray cone with a relatively larger fan angle and a second ray cone with a relatively smaller fan angle scan an object circularly or spirally. The first ray cone generates a first dataset A and the second ray cone generates a dataset B. The dataset B of the smaller ray cone is supplemented with other data at the edge to give an expanded dataset B+ for reconstruction of the CT representation. The expanded dataset B+ of the second, smaller ray cone and the dataset A of the first, larger ray cone is subjected to a convolution operation to give datasets B+? and A?. Finally, a back projection to reconstruct sectional images or volume data is respectively carried out from the convoluted datasets B+? and A?. The dataset B is supplemented with data of the dataset A and supplementary data are removed from the dataset B+? after the convolution but before the back projection.

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.

Abstract: A method is for production of tomographic section images, in particular X-ray CT images, of an at least partially periodically moving examination object with periodically changing movement and rest phases, preferably of a heart of a living being. A number of focus detector combinations are used, with the time resolution of the CT scanner being significantly increased by supplementary combination of detector data in the correct phase. On the one hand, a number of focus detector combinations which scan an examination object at the same time are used; and on the other hand a number of adjacent movement cycles of a periodically moving examination object are performed.

Abstract: An imaging method is for a multi-slice spiral CT scan with 3D back projection. Use is made, for the reconstruction of the absorption value of at least one voxel, of the measured and filtered data that are produced by rays which penetrate the at least one voxel. A CT unit is further used to carry out the method. In the method, the filtering of the data, required for the reconstruction, in the image of the virtual detector is performed in the direction of the projection of spiral segments imaged thereon which are produced by the spiral scanning over a prescribed angular range. The CT unit includes a device for carrying out directional filtering of this type.

Abstract: A method and CT scanner are proposed for the production of tomographic section images, in particular X-ray CT images, of a periodically moving object with periodically changing movement and rest phases. For scanning, a number of focus detector combinations with flat detectors are moved on coaxial spiral paths and movement signals from the moving object are measured at the same time in order to detect movement and rest phases. Further, the time correlation between the movement data and the detector output data stored and axial segment image stacks are then reconstructed independently of one another from sub-segments of the spiral paths using the detector output data from each detector which represent a rest phase of the moving object. Additionally, segment image stacks from the n spiral paths of the n focus detector combinations at the correct time are added up in a complementary angle form and in layers to form 180° tomography section images.

Abstract: A method is for examining a body region of an examination object, which body region performs a periodic movement in the form of a sequence of movement cycles including phases of the periodic movement. The method preferably uses a CT apparatus with a radiation source for generating a radiation that penetrates through the examination object at different projection angles, and a detector system for the radiation emerging from the radiation source. An image, at least of the body region that performs the periodic movement, is determined by way of an electronic computing device from the output data of the detector system, which correspond to the detected radiation and are used as measurement data. In this case, it is provided that, from a number n?1 of preferably successive movement cycles, data intervals are taken with respect to the same phase of the periodic movement. The overall length of these intervals produces at least one reconstruction interval that suffices for determining an image.

Abstract: A method is for improving CT image data from a moving examination object, in particular a beating heart. The method includes moving a focus on a circular track about the examination object, wherein scanning data streams, measured in parallel and in a fashion correlated with one another, are collected from a multirow detector. Further, movement data of the examination object are also collected. Angularly complementary data record elements of the same movement phase are retrospectively selected from a number of movement cycles. The data record elements are then reconstructed and reformatted to form incomplete CT images. Subsequently, the incomplete CT images are added up to form complete CT images.

Abstract: An imaging tomography apparatus, in particular an x-ray computed tomography apparatus, has two acquisition systems capable of rotating around a common rotation axis. Each of the acquisition systems has a radiator as well as a detector. The maximum measurement fields scanned by the two acquisition systems given rotation around the rotation axis are of different sizes, or can be adjusted to different sizes. In particular, the lengths of both detectors measured in the azimuthal direction—are of different sizes. The tomography apparatus can be fashioned to scan the entire body cross-section of an examination subject or of a patient with conventional temporal resolution, and to scan detail region, such as a heart region, with an increased temporal resolution or accelerated data acquisition rate in comparison to a device with only one acquisition system.

Abstract: A method is disclosed for a multislice computer assisted tomograph, capable of carrying out a spiral scan of an object volume with a pitch p selected to be small enough that each slice of the object volume is multiply detected during the spiral scan. The method includes calculating, using measured data of two temporally consecutive at least one of revolutions and half revolutions, an image of the object volume from which a change inside the object volume between the two temporally consecutive at least one of revolutions and half revolutions is directly visible. An embodiment of the method can permit, for example, the detection and visualization of dynamic processes with an enhanced time resolution.

Abstract: A method is for taking tomograms of a patient's beating heart with the aid of a computed tomography unit. ECG signals of the beating heart are recorded. In order to reconstruct the cardiac tomograms, use is made of detector data that originate from a selected cycle area of the cardiac cycle. The cycle area from which the data for the reconstruction originate is selected automatically and individually per cycle, for at least one cardiac cycle, by use of pattern recognition.

Abstract: A method is for taking computed tomography scans with the aid of a CT unit and to a CT unit. An X-ray tube is moved in a circle or spiral about a z-axis in combination with a detector situated opposite and an object is scanned. The X-ray tube includes a jumping focus with two or more different jumping focal positions relative to the X-ray tube. Parallel data records are formed from the detector data obtained, and tomograms are reconstructed therefrom. When forming the parallel data records, account is taken of the different position of the respectively current jumping focus in relation to the X-ray tube (=jumping focal position) in the radial direction.

Abstract: A computed tomography unit includes at least one X-ray tube, that scans an object in a fashion rotating in a circle or spiral about a z-axis, in combination with an oppositely situated detector having a multiplicity of detector rows. Each detector row includes an aperture ?z in the z-direction, having a multiplicity of detector elements. Between the X-ray tube and detector, a detector diaphragm is arranged that reduces the aperture ?z of the detector rows in the z-direction. The X-ray tube includes a focus, of variable location relative to the X-ray tube and which alternatingly assumes during scanning at least two different positions that have different z-coordinates relative to the X-ray tube R.

Abstract: A method and a CT unit are proposed for producing CT images of an examination object having a periodically moving subregion, preferably a beating heart, by multi-planar reconstruction. Subsequent to joining the axial images with pixels from a number of partial volumes calculated for the rest phases, a reduction takes place to reduce artifacts occurring in overlap regions. This is done by carrying out threshold value formation in the zone of the boundary regions of the partial volumes with result image Dz. A pixel-oriented median filtering then occurs, resulting in image Mz. A differential value image is then produced using Fz=Dz?Mz. Subsequently, two-dimensional lowpass filtering is applied to Fz to produce a result image Gz. Finally, a calculation of Bz?Gz is used to form the final image Ez.

Abstract: A method is for filtering tomographic 3D images of an examination object. The examination object is imaged by using a volume model that divides the volume of the examination object into a multiplicity of three-dimensional image voxels with individual image values, wherein the image value of each voxel reproduces an object-specific property of the examination object in this volume. After the reconstruction of the total volume for each voxel, variances are calculated in a prescribed region or radius R in order to determine contrast jumps and their spatial orientation with their tangential planes T. The image values in the tangential plane T are filtered with a two-dimensional convolution, and subsequently the original voxel data are mixed in weighted fashion with the filtered voxel data.

Abstract: A method is for producing CT images of a periodically moving object to be examined, in particular a method for cardio volume reconstruction for multi-row CT units in spiral mode. A multi-row CT unit designed is further designed therefore. A small partial revolution segments along a revolution spiral is used to calculate in each case per partial revolution segment a plurality of segment images that are converted in a second step to partial images in the target image plane (for example axial plane) and are assembled with the correct phase to form complete images.