Abstract: A method is for imaging of an examination region of an object to be examined with a computed tomography system. In an embodiment, the method includes recording of first and second projection measurement data with a common x-ray source-detector system, the first projection measurement data being recorded with a first x-ray spectrum in a first angular sector and the second projection measurement data being recorded with a second x-ray spectrum in a second angular sector; Creation of first and second start image data from the first and second projection measurement data via a first reconstruction method; and coupled iterative reconstruction of first result image data on the basis of the first start image data and of second result image data on the basis of the second start image data, the first result image data and the second result image data each featuring a complete image of the examination region.

Abstract: A method is for imaging of an examination region of an object to be examined with a computed tomography system. In an embodiment, the method includes recording of first and second projection measurement data with a common x-ray source-detector system, the first projection measurement data being recorded with a first x-ray spectrum in a first angular sector and the second projection measurement data being recorded with a second x-ray spectrum in a second angular sector; Creation of first and second start image data from the first and second projection measurement data via a first reconstruction method; and coupled iterative reconstruction of first result image data on the basis of the first start image data and of second result image data on the basis of the second start image data, the first result image data and the second result image data each featuring a complete image of the examination region.

Abstract: In a computer tomography system having an x-ray detector with a detector surface at which sensor pixels, for detection of x-ray radiation, are distributed non-uniformly, and a method for operating such a system, either a pitch factor is selected, and a value range for an extent of a reconstruction field for image data is determined dependent on the distribution of the sensor pixels and dependent on the selected pitch factor, or a value for the extent of the reconstruction field is selected, and a value range for the pitch factor is determined dependent on the distribution of the sensor pixels and dependent on the selected value for the extent of the reconstruction field.

Abstract: A method, a computer program, a computer program product and a computed tomography system are disclosed. The image data is a spatially three-dimensional reconstruction. At least one value for an image metric of the image data is determined. A motion field for motion compensation of the image data is then determined on the basis of image data as a function of the image metric. Essentially, partial image data is determined, wherein the partial image data corresponds in each case to the spatially three-dimensional reconstruction from scan data of an angular sub-range. The motion field of the image data is determined at the control points via an optimization method as a function of the image metric, so that, thereafter, the partial image data is transformed in accordance with the motion of the motion field. New image data is then produced by merging the partial image data.

Abstract: A method is disclosed for reconstructing image data of an examination object from measured data, the measured data being captured during a rotating movement of a radiation source of a computed tomography system around the examination object. In at least one embodiment, different iteration images of the examination object are determined successively from the measured data by way of an iterative algorithm, wherein with the iterative algorithm the current iteration image at any one time is high-pass-filtered and weighted as a function of contrast using a variable which contains contrast information relating to the current iteration image at that time.

Abstract: A method is disclosed for the reconstruction of image data of an object under examination from measured data, wherein the measured data has been acquired during a relative rotational movement between a radiation source of a computed tomography system and the object under examination. A delimited area between the radiation source and a detector represents a field of view, in respect of which measured data can be acquired. During the measured data acquisition, parts of the object under examination were located at least partly outside of the field of view. A reconstruction is carried out of first image data from the measured data. The first image data is modified via a threshold value comparison, and the modified data is processed with a morphological filter, and projection data is calculated. The measured data is modified using the projection data, and, second image data is reconstructed.

Abstract: In a computer tomography system having an x-ray detector with a detector surface at which sensor pixels, for detection of x-ray radiation, are distributed non-uniformly, and a method for operating such a system, either a pitch factor is selected, and a value range for an extent of a reconstruction field for image data is determined dependent on the distribution of the sensor pixels and dependent on the selected pitch factor, or a value for the extent of the reconstruction field is selected, and a value range for the pitch factor is determined dependent on the distribution of the sensor pixels and dependent on the selected value for the extent of the reconstruction field.

Abstract: A method and image reconstruction facility are disclosed for reconstructing an image dataset based on a projection dataset acquired with the aid of an x-ray computed tomography apparatus. With an embodiment of the method, a first image dataset is reconstructed based on the projection dataset and an edge image dataset is generated, which indicates a measure of an edge strength of edges occurring in at least one spatial/temporal direction in the first image dataset, as a function of location. An output image dataset is then generated based on the first image dataset, with the resolution in the first image dataset being increased as a function of location in at least one spatial/temporal direction taking into account the edge image dataset.

Abstract: A method is disclosed for the reconstruction of image data of an examination object from measurement data. First and second image data are reconstructed from the measurement data with a first and second respective image characteristic, with an enhanced signal-to-noise ratio of the second image characteristic relative to the first image characteristic. Enhanced image data is calculated using an iterative algorithm using the first and the second image data. In the case of the iterative algorithm, a low pass is applied to a difference between the first image data and the image data of an iteration cycle, and a high pass to a difference between the second image data and the image data of the iteration cycle.

Abstract: A method is disclosed for determining a motion field in an image space of a CT image data set for a partially and cyclically moving object, wherein a projection data set from a CT system covering a motion phase and a projection angle range is recorded, and an iterative determination of the motion field by minimizing a cost function from CT image data sets which are motion-compensated and reconstructed making use of motion fields and which have a first image resolution, with a first analytical reconstruction algorithm, the cost function being based on raw data or transformed into the image space. A method for generating a motion-compensated CT image data set for a partially and cyclically moving object is also disclosed, along with a computer system for image reconstruction and a CT system.

Abstract: A method, a computer program, a computer program product and a computed tomography system are disclosed. The image data is a spatially three-dimensional reconstruction. At least one value for an image metric of the image data is determined. A motion field for motion compensation of the image data is then determined on the basis of image data as a function of the image metric. Essentially, partial image data is determined, wherein the partial image data corresponds in each case to the spatially three-dimensional reconstruction from scan data of an angular sub-range. The motion field of the image data is determined at the control points via an optimization method as a function of the image metric, so that, thereafter, the partial image data is transformed in accordance with the motion of the motion field. New image data is then produced by merging the partial image data.

Abstract: A method is disclosed for reducing step artifacts in the forward increment direction of a cardio CT representation. In at least one embodiment, volume recordings or section images of first and second sub-volumes of a heart volume, which lie adjacent to one another in the forward increment direction and partially overlap in an overlap region, are recorded by a computer tomography system. Each sub-volume's detector data is used for the reconstruction coming from different heart cycles. Finally, a displacement vector relative to a second sub-volume is determined at least for a selected point of the overlap region of a first sub-volume and the second sub-volume is subjected at least partially to a spatial transformation according to the at least one displacement vector.

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: The method includes a weighted highpass filtering of the image data takes place here, with the weighting taking account, image element by image element, of an image noise on the respective image element in different directions such that increasing noise results in a stronger highpass effect. A noise-reducing smoothing of the image data takes place using the weighted highpass filtering.

Abstract: A method is disclosed for reconstructing image data of an examination object from measured data, wherein the measured data was captured previously during a relative rotary motion between a radiation source of a computed tomography system and the examination object. In at least one embodiment, the measured data is modified to achieve a particular grayscale characteristic of the image data to be reconstructed. The image data is calculated by way of an iterative algorithm using the modified measured data, wherein no arithmetic step for reducing noise is employed in the iterations.

Abstract: Method for the noise reduction of CT image data and an image processing system are disclosed, with a scanning of an examination object and generation of at least two CT image data records each taking place on the basis of a different x-ray energy spectrum. In at least one embodiment, a break-down of the data image records into at least two broken-down image data records takes place in each instance, with a lowest local frequency band (f(1)) with the index k=1 and at least one high local frequency band (f(k)) with the index k=2 to N.

Abstract: A method and an X-ray system are disclosed for reduction of the radiation dose used within the framework of an imaging X-ray examination. In at least one embodiment, for each pixel of a recorded image, structure information of a structure which may be present at a distance around the examined pixel is determined and a direction-dependent lowpass filter is applied to the pixel examined in each case, which filter's spatial coverage is less than the distance and which takes into account the morphological information of a structure which may be present with a direction-dependent weighting of the lowpass filter.

Abstract: A method is disclosed for reconstruction of image data of an examination object from measured data, wherein the measured data was captured during a relative rotational motion between a radiation source of a computed tomography system and the examination object. Image data of the examination object is determined from the measured data. In at least one embodiment, new image data is obtained by noise-reducing processing of the image data, in which weighted high-pass filtering of the image data is performed, the weighting taking account of differences between pixel values of different pixels such that increasing differences result in a weaker high-pass effect. A noise-reducing smoothing of the image data is performed using the weighted high-pass filtering.

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 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.