Abstract: In order to regularize a reconstruction method associated with computed tomography (CT), in at least one example embodiment, information relating to the statistics of the attenuation values of the reconstructed object is also included in the form of the logarithmic probability function of the attenuation values. This information can be obtained from the regions of those image parts which are still completely contained in a scanning field of view (SFOV), but nevertheless lie in the vicinity of the region where the object leaves the SFOV. Furthermore, the information may be used in an algebraic reconstruction method by adding a boundary condition term to the cost function to be minimized.

Abstract: A method and an X-ray device are disclosed for creating an X-ray projection image of a three-dimensional object under examination and for displaying the projection image. In at least one embodiment, pixel images are recorded from two different perspectives and a projection image is created by overlaying the two pixel images, wherein perspective-related offset of the mapping image pixels is taken into account, pixel-by-pixel, in relation to an imaging surface in the object under examination.

Abstract: Methods for post-processing raw detector signals of an x-ray or gamma detector are disclosed. According to at least one embodiment of the invention, raw detector signals are filtered, an associated filtered signal is determined at least for a subset of the raw detector signals, and those filtered signals whose signal value is less than zero are then respectively replaced by a signal value greater than zero.

Abstract: A method is disclosed for the reconstruction of picture data of a moving object under examination from measurement, with the measurement data having been recorded beforehand for a relative rotational movement between a radiation source of a computed tomography system and the object under examination. In at least one embodiment, first picture data is computed from a complete measurement dataset of the measurement data for a picture reconstruction, and second picture data is computed from an incomplete measurement dataset for a computed tomography picture reconstruction. The first picture data and the second picture data are combined into third picture data, with the combination being computed using location-dependent movement information of the object under examination.

Abstract: A multi-emitter computed tomography scanner is disclosed, including a plurality of x-ray emitter/detector arrangement pairs arranged offset at an angle to one another. In at least one embodiment, the detector arrangements of the pairs are designed to be energy selective.

Abstract: A method is disclosed for reconstruction of image data of an object under examination from measurement data, with the measurement data having been captured during a relative rotational movement between a radiation source of a computed tomography system and the object under examination. In at least one embodiment, first image data is computed by the measurement data being modified to obtain a specific gray value characteristic of the first image data to be reconstructed and the first image data is computed by way of an iterative algorithm using the modified measurement data. Second image data is also computed by a series of chronologically-consecutive images being reconstructed and processing being carried out on the series of images to reduce temporal noise. Finally a combination of the first and the second image data is carried out.

Abstract: A method is disclosed for the reconstruction of image data of a moving object to be examined from measurement data, wherein the measurement data has previously been established in a relative rotational movement between a radiation source of a computed tomography system and the object to be examined. In at least one embodiment, first image data is reconstructed from an incomplete measurement data record by way of an iterative algorithm, wherein in the iterative reconstruction a dimension is used which contains probability information relating to pixel values of the image data to be reconstructed.

Abstract: A method is disclosed for generating computed tomography image data of a volume of interest from X-ray CT data sets generated by a computed tomography system during scanning of an examination subject on a helical path rotating around a longitudinal system axis in the infeed direction. In at least one embodiment, at least two volume-based reconstructions of the volume of interest are performed by way of differential back-projection over surfaces constituted by different groups of M-lines, followed in each case by an inverse Hilbert transformation. The method further includes combining different reconstructed volumes to form a final reconstruction of the volume of interest.

Abstract: A computed tomography device (CT device) includes a user interface, via which the standard settings characterizing the CT measurement can be performed. At the same time, in a method and a computed tomography device for carrying out this method, filtering behavior of the filter electronics is adapted to the configuration of the standard settings by the system computer.

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 is for image reconstruction for computed tomography with a non-one-dimensional, extended detector. The rays of the detector are weighted during the backprojection as a function of their position in the beam.

Abstract: A method is disclosed for reconstructing image data of an examination object from measurement data of a computed tomography system, the examination object having been irradiated simultaneously by a number of X-ray sources while the measurement data was being acquired so that different projections of the examination object associated with the number of X-ray sources were acquired simultaneously for each detector element. In at least one embodiment, different iteration images of the examination object are determined one after the other from the measurement data by way of an iterative algorithm, a computation operation being employed with the iterative algorithm, which is applied to the iteration images and takes the presence of the number of X-ray sources into account.

Abstract: A method is disclosed for reconstructing image data of an examination subject from measured data, wherein the measured data was acquired in the course of a relative rotational movement between a radiation source of a computed tomography system and the examination subject. A limited area between the radiation source and a detector represents a field of view in respect of which measured data can be acquired, and parts of the examination subject were located at least temporarily outside the field of view in the course of the measured data acquisition. In at least one embodiment, first image data is reconstructed from the measured data, and a boundary of the examination subject is determined with the aid of the first image data. The first image data is subsequently modified using the determined boundary, and projection data is calculated from the modified first image data. The measured data is modified using the projection data, and finally second image data is reconstructed from the modified measured data.

Abstract: An imaging method is disclosed for variable pitch spiral CT. In at least one embodiment, the method includes spiral scanning of an examination object lying on a patient table, with the aid of a beam emanating from at least one focus, and the aid of a detector arrangement of planar design lying opposite the focus, the detector arrangement supplying output data that represent the attenuation of the beams during passage through the examination object; filtering the output data; weighted back projection of the filtered output data; and visualizing a layer or a volume on a display unit on the basis of the back projected output data. In at least one embodiment, a non constant pitch of the spiral scanning is taken into account computationally during the back projection. In at least one embodiment, a CT machine is disclosed for carrying out the above named method.

Abstract: A circuit arrangement of a quanta-counting detector with a multiplicity of detector elements is disclosed, wherein the X-ray quanta registered in each detector element generate a signal profile. In at least one embodiment, the circuit arrangement, in each detector element, includes: at least one first comparator with a first energy threshold lying in the energy range of the measured X-ray quanta and at least one second comparator with a second energy threshold lying above the energy range of the measured X-ray quanta, the at least one first and second comparators being connected to the detector element. Further, the at least two comparators have a logical interconnection, wherein at least a first comparator and a second comparator are connected to the inputs of an XOR gate, and each XOR gate connected to a first comparator is connected to precisely one edge-sensitive counter.

Abstract: A method and an image reconstruction device are disclosed for reconstructing image data on the basis of input projection data obtained via an X-ray computerized tomography system. A target convolutional kernel is selected, which, when reconstructing image data from the input projection data using simple filtered back projection, would lead to target image characteristics. Image data is then reconstructed using an iterative reconstruction method of at least one embodiment.

Abstract: A method and a device are disclosed for generating a CT image with a high time resolution using a computed tomography scanner which has at least two recording systems which are operated at different X-ray energy spectra. In at least one embodiment of the process, CT images are firstly reconstructed in each case from a semi-rotation with the two recording systems, with irradiated lengths of the contrast agent-enriched structures and the soft tissue being calculated therefrom. Subsequently, a common X-ray energy is assumed and artificial measurement data records are calculated therefor, using the knowledge of the irradiated lengths for both recording systems at the same common X-ray energy. The artificial measurement data of respectively a quarter-rotation per recording system is then used to calculate the final CT image with a high time resolution. The method affords the use of dual-energy scans without losing the high time resolution available in dual-source systems.

Abstract: A method and a device are disclosed for segmenting at least one substance in an x-ray image. In at least one embodiment of the method, two attenuation values relating to different energies of an x-radiation are acquired in relation to each pixel. The pixels are mapped into a two-dimensional feature space on the basis of the acquired attenuation values, and there is subsequently determined as assessment variable from the mapping of an image environment respectively assigned to the pixels the number of those pixels that fall in a classification region assigned to the substance. It is then possible to calculate in a simple way on the basis of the assessment variable a segmented image that contains the substance and in which misclassification can largely be avoided by taking account of the neighborhood relationship of the pixels.

Abstract: At least one embodiment of the invention relates to a method for the reconstruction of image data of an examined object from measuring data, wherein the measuring data were detected by a detector within and outside of its Tam-Danielsson window during a relative spiral movement between a radiation source of a computer tomography system and the examined object. As a result of the spiral movement, the measuring data outside of the Tam-Danielsson contain interruptions. A mathematically precise first reconstruction of first image data is realized in at least one embodiment based on the measuring data by using only measuring data from the Tam-Danielsson window.

Abstract: A method is disclosed for reconstructing image data of a moving examination object from measurement data, wherein the measurement data was captured in the course of a relative rotational movement between a radiation source of a computed tomography system and the examination object. In at least one embodiment of the method, a first image of the examination object is calculated from a complete measurement data record of the measurement data for an image reconstruction and a second image of the examination object is calculated from an incomplete measurement data record of the measurement data for an image reconstruction. Frequency splitting of the first and second images takes place respectively in at least one low-frequency and one higher-frequency component and the image data of the second image is supplemented in the low-frequency component with image data of the low-frequency component of the first image.