Patent application number | Description | Published |
20080198965 | Method for producing tomographic pictures with the aid of an X-ray computed tomography system with scattered radiation correction - A method is disclosed for producing tomographic pictures with the aid of an X-ray CT system including at least two X-ray sources arranged on a gantry with an angular offset to scan an examination object. In at least one embodiment of the method, in order to determine the scattered radiation distribution, pre-scanning is carried out in which the X-ray sources rotate about the examination object and the dose rate is modulated as a function of the rotation angle, no radiation dose is output over the majority of the revolution, at specific pre-scan angles a dose rate is produced briefly and individually in each case by the X-ray sources of the focus/detector systems, and the received scattered radiation is measured simultaneously by the detectors of the at least one other focus/detector system. Moreover, at least one embodiment of the invention also relates to an X-ray CT system having at least two focus/detector systems and an arithmetic and control unit with a memory for program code that carries out during operation the method steps being stored. | 08-21-2008 |
20080240340 | Method for scattered radiation correction in x-ray imaging devices - A method is disclosed for scattered radiation correction in x-ray imaging devices having a number of x-ray sources that can be moved around an examination object in at least one scanning plane during a measurement pass. During the measurement pass, a number of x-ray projections are recorded at different projection angles with simultaneous use of the x-ray sources. In at least one embodiment of the present method, parameters characterizing an outer object contour are determined in the scanning plane from measured data of different x-ray projections. In at least one embodiment, on the basis of one object contour section whose characterizing parameters have been determined from x-ray projections that lie in front of and/or behind the respective x-ray projection by a defined projection angle range, for each x-ray projection an assigned scattered radiation distribution is then retrieved or is interpolated in a database from scattered radiation distributions for object contour sections with similar characterizing parameters. This scattered radiation distribution is then used for the correction of the measured data for the respective x-ray projection. In at least one embodiment, the method enables scattered radiation correction in conjunction with operation of the x-ray sources. | 10-02-2008 |
20080292170 | Method for scattered radiation correction in an X-ray computed tomography system, and method for generating a tomographic display corrected for scattered radiation, and/or an X-ray computed tomography system - A method is disclosed for scattered radiation correction in an X-ray computed tomography system having at least two tube-detector systems. It is provided, according to at least one embodiment, to make use of a data record that includes data projections required for the reconstruction and a prescribed number of first scattered radiation projections. Respective scattered radiation components for the scattered radiation correction of all data projections are determined on the basis of the first scattered radiation projections and second scattered radiation projections determined therefrom. | 11-27-2008 |
20080292171 | Method and X-ray CT system for generating computed tomography displays - A method is disclosed for generating computed tomography displays, in which with the aid of at least one X-ray source, an examination object is scanned in a rotationally circulating fashion with a measured dose rate dependent on the circulation angle, projection data are collected from a multiplicity of viewing angles, and at least similarly redundant projection data from angularly identical or angularly complementary projection angles with a different measured dose are interpolated with distance weighted relative to a projection value and are used for reconstruction. According to at least one embodiment of the invention, during the distance weighted interpolation of the at least similarly redundant projection data an additional noise optimizing weighting is carried out as a function of the noise present per projection value. Furthermore, an X-ray computed tomography system is disclosed for generating tomographic displays of an examination object with the aid of an arithmetic logic unit, including computer program code for evaluating detector data and carrying out a reconstruction, the arithmetic logic unit including program code that during operation executes at least one embodiment of the method. | 11-27-2008 |
20090122954 | Method for the extrapolation of truncated, incomplete projections for computed tomography - At least one embodiment of the present invention relates to a method for extrapolation of truncated, incomplete projections for computed tomography. At least one embodiment of the method is based on the use of CT units having multi-row detectors and scanning in spiral scan operation and includes at least the following. Firstly, scanning of an examination object with the aid of a beam. Secondly, detection of complete and incomplete projection data during a scan. Thirdly, the carrying out of a parallel rebinning for the detected projection data. Fourthly, determining incomplete, truncated projections based on analysis of the 3D signal path in the 3D sinogram belonging to each voxel in the object region. Fifthly, extrapolating the incomplete, truncated projections by continuing the terminated or discontinuous 3D signal paths according to | 05-14-2009 |
20090122955 | Method for the extrapolation of truncated, incomplete projections for computed tomography - A method is disclosed for extrapolation of truncated, incomplete projections for computed tomography. In at least one embodiment, the method includes the following method steps. Firstly, scanning of an examination object with the aid of a beam. Secondly, detection of complete and incomplete projection data during a scan. Thirdly, the carrying out of a parallel rebinning for the detected projection data by resorting and conversion of the projection data P(α, β, q) present in fan geometry into projection data P(θ, t, q) present in parallel geometry. Fourthly, for the complete parallel projections, projectionwise determination of mth moments, at least for m=0 and m=1, the following holding for the mth moment of a parallel projection P | 05-14-2009 |
20090124892 | Method for measuring cardiac perfusion in a patient and CT system for carrying out the method - A method and a CT system are disclosed for measuring the perfusion in vessels and/or muscles of the heart (cardiac perfusion) in a patient. In at least one embodiment of the method the patient receives a contrast agent bolus, the patient is scanned for a scan period of a plurality of cardiac cycles in a scan field of a CT system controlled by the cardiac rhythm, a plurality of CT image data is reconstructed from projection data of a particular cardiac phase from respectively one cardiac cycle, and the temporal profile of the absorption values at at least one location in the heart is determined and displayed on the basis of a plurality of CT image data at successive times. At least one embodiment of the invention is distinguished by the fact that during the examination, the patient is repeatedly and alternately moved in opposite directions along a system axis of the CT system such that his cardiac region passes through the scan field at a cardiac phase range and the cardiac region is completely scanned spirally. | 05-14-2009 |
20090129540 | Correcting transverse scattering in a multi-emitter CT scanner - 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. | 05-21-2009 |
20090141855 | CT scanner and method for helical scanning of an examination object which has at least one portion undergoing periodic motion - At least one embodiment of the present invention relates to a CT scanner and/or a method for helical scanning of an examination object which has at least one portion undergoing periodic motion. In at least one embodiment, the CT scanner includes at least one bearing apparatus, arranged along a system axis of the CT scanner, for bearing the examination object, two scanning systems which can rotate around the system axis and which are arranged coaxially, respectively having a focus from which a beam can be emitted and a flat-design detector array, arranged opposite the respective focus, including a multiplicity of distributed detector elements which can detect the rays of the beam, wherein projection data can be generated by the scanning systems which represents the attenuation of the rays while traversing the examination object, and wherein the bearing apparatus and/or the scanning systems can be displaced along the system axis, a first device/module, preferably an EKG, which can detect and store rest and movement phases of the examination object which has at least one portion undergoing periodic motion in the form of measurement data, and a second device/module which can, based on the measurement data and/or data derived therefrom, trigger and/or control a displacement of the scanning systems and/or the bearing apparatus along the system axis. | 06-04-2009 |
20090161935 | Method for improving the quality of computed tomography image series by image processing and CT system comprising a computational unit - A method, a computational unit and a CT system are disclosed for improving the quality of CT image series. In at least one embodiment, the method includes scanning an examination object over a period of time which permits the acquisition of at least two temporally offset projection data records of an identical recording region; generating at least two temporally offset tomographic image data records, each having a multiplicity of pixels, by reconstructing the projection data records; transforming the image data records into transformation data records of at least two spatial frequency ranges; calculating temporal fitted values of the transformation data records for some of the spatial frequency ranges, and replacing the values of the transformation data records which were fitted by the calculated fitted values; performing an inverse transform of the transformation data records with the fitted values to form new image data records; and displaying the new image data records. | 06-25-2009 |
20100021033 | Method for differentiating and displaying moving and stationary heart regions of a patient in X-ray CT - A method is disclosed for differentiating and displaying moving and stationary heart regions of a patient in X-ray CT. In at least one embodiment, the method includes carrying-out circular or helical scanning of a patient in the region of his or her heart using an X-ray CT scanner including a detector with a multiplicity of detector elements, and storing at least one sinogram from a multiplicity of projection data from encircling projection directions; and reconstructing at least one tomographic display of the heart from the at least one sinogram and displaying the at least one reconstructed display of the heart. According to at least one embodiment of the invention, the projection data are Fourier transformed, filtered with respect to a predetermined frequency, inverse transformed, reconstructed, and output together with the tomographic display of the heart. | 01-28-2010 |
20100027736 | Method for producing tomographic images, control device, tomography unit and computer program product - A method is disclosed for producing tomographic images relating to different movement phases of a periodically moving object with the use of a tomography unit that includes a recording system that is arranged rotatably about a z-axis of the tomography unit, the recording system including an X-ray tube to which a tube current can be applied and a detector ( | 02-04-2010 |
20100054569 | Method for creating computed tomography recordings of a patient with metallic components - A method is disclosed for creating computed tomography recordings of a patient with metallic components. In at least one embodiment, the method includes scanning the patient by use of an x-ray tube detector system, with at least one sinogram being compiled; determining the detector signal data, which was attenuated by the metallic components in the patient; deleting the detector signal data, which was influenced by metallic components; determining the beam tracks in the sinogram at least of the volume elements, which are struck by beams which are attenuated by the metallic components and which cross the beam track of the deleted detector signal data in the sonogram; determining a minimal measurement value on each beam track respectively; adding together the minimal measurement values of the beam tracks to obtain the measurement points of the deleted detector signal data crossed by these beam tracks in the sonogram; and using this at least one sinogram determined in this manner to reconstruct computed tomography recordings of the patient without a metallic component, and displaying the reconstructed computed tomography recordings of the patient with metallic components. | 03-04-2010 |
20100074398 | Motion control method and motion control module, image processing actuation method and image processing actuation module - A motion control method is disclosed for controlling a relative scan feed motion of an object bearing device toward a scanner unit of a computed tomography system. Here, scan motion control signals are generated parallel to the scan feed motion for controlling the scan feed motion, which scan motion control signals are derived from variable input data obtained in parallel during a scan procedure. In at least one embodiment, the variable input data includes motion signals which represent the object motion cycle determined with the aid of an electrocardiogram, and the speed of the scan feed motion is reduced if an extrasystole is detected. Furthermore, at least one embodiment of the invention relates to a motion control module suited to this and/or an image processing actuation method and/or an image processing actuation module for actuating an image processing system. | 03-25-2010 |
20100074503 | Method for generating computed tomography image data records of a patient in the heart CT scan during a perfusion control by applying contrast agent - A method is disclosed for generating computed tomography image data records of a patient in a heart CT scan during a perfusion control by applying contrast agent. In at least one embodiment, a plurality of temporally consecutive CT data records are recorded as an exposure series with a CT system and if necessary are reconstructed. These CT data records are improved for better visualization of the perfusion by way of electronic filtering and post-processing, with all projection and/or image data determined during a CT scan being used, however with the aid of frequency filtering only the data of a projection or of a reconstructed image for generating a final representation being used which does not fall within a predetermined local frequency range of a heart movement. | 03-25-2010 |
20100092060 | X-Ray CT system and method for creating tomographic recordings with two x-ray energy spectra - An x-ray CT system and a method are disclosed for creating tomographic recordings with the aid of an x-ray CT system, with two emitter/detector arrangements operating with an angular offset on a gantry with at least two different x-ray energy spectra. In at least one embodiment, at least one first recording is reconstructed from detector data from two quarter rotations with different x-ray energy spectra and at least one second recording is created from detector data of a scan of at least one of the emitter/detector arrangements over a half rotation. According to at least one embodiment of the invention, the recordings are subjected to high-pass filtering or low-pass filtering in respect of their spatial frequencies and then the filtered recordings are combined to give a resulting recording. | 04-15-2010 |
20100177862 | SCANNING AND RECONSTRUCTION METHOD OF A CT SYSTEM AND CT SYSTEM - A method is disclosed for scanning an examination object with a CT system and the generation of at least one computed tomographic sectional view from data obtained from the scanning and a CT system. In at least one embodiment, data used for generating the at least one sectional image is filtered out with different intensities as a function of a predetermined time range and/or projection angle range of the measurement of high local frequencies. | 07-15-2010 |
20100189213 | CORRECTING TRANSVERSE SCATTERING IN A MULTI-EMITTER CT SCANNER - 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. | 07-29-2010 |
20100195888 | CT IMAGE RECONSTRUCTION OF A MOVING EXAMINATION OBJECT - At least one embodiment of the invention relates to a method for the scanning of a moving examination object with a CT system, in which during a rotational movement of a transmitter/receiver pair around the examination object, data is captured. Further, sectional images of the examination object are determined from the data by way of an iterative algorithm, where motion information relating to the movement of the examination object during the data acquisition is taken into account in the iterative algorithm. At least one embodiment of the invention further relates to a CT system and a computer program. | 08-05-2010 |
20100220912 | METHOD FOR THE NOISE REDUCTION OF CT IMAGE DATA AND IMAGE PROCESSING SYSTEM - 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 | 09-02-2010 |
20100246751 | METHOD AND IMAGE RECONSTRUCTION DEVICE FOR RECONSTRUCTING IMAGE DATA - 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. In at least one embodiment, the method includes a) reconstructing image data of a first iterative stage from the input projection data, b) generating synthetic projection data on the basis of the image data of the current iterative stage, c) forming difference projection data on the basis of the input projection data and the synthetic projection data, d) generating residue image data from the difference projection data, e) combining the residue image data with the image data of the current iterative stage to form image data of an additional iterative stage, wherein the image data of the current iterative stage is subjected to filtering before or during combination with the residue image data by using a regularization convolutional kernel which is determined on the basis of the selected target convolutional kernel, and f) repeating b) to e) until a termination condition occurs. | 09-30-2010 |
20100246917 | CONTRAST-DEPENDENT REGULARIZATION STRENGTH IN THE ITERATIVE RECONSTRUCTION OF CT IMAGES - 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. | 09-30-2010 |
20110033097 | CT IMAGE RECONSTRUCTION FOR IMPROVING TEMPORAL RESOLUTION IN CARDIO CT - 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. In a further processing step the second image thus supplemented is improved using the first image, in that errors due to the incompleteness of the measurement data record of the second image are reduced. | 02-10-2011 |
20110052030 | ITERATIVE CT IMAGE FILTER FOR NOISE REDUCTION - 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. | 03-03-2011 |
20110188723 | CT Image Reconstruction In The Extended Field Of View - 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. | 08-04-2011 |
20110188724 | CT MEASUREMENT WITH MULTIPLE X-RAY SOURCES - 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. | 08-04-2011 |
20110293159 | ITERATIVE CT IMAGE RECONSTRUCTION WITH A FOUR-DIMENSIONAL NOISE FILTER - 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. | 12-01-2011 |
20110293160 | Iterative Reconstruction Of CT Images Without A Regularization Term - 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. | 12-01-2011 |
20110317901 | Temporal Resolution In Cardio CT - 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. | 12-29-2011 |
20120039518 | METHOD, COMPUTER READABLE MEDIUM AND SYSTEM FOR ITERATIVE IMAGE FILTERING WITH ANISOTROPIC NOISE MODEL FOR A CT IMAGE - 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. | 02-16-2012 |
20120121148 | METHOD FOR REDUCTION OF THE RADIATION DOSE USED WITHIN THE FRAMEWORK OF AN X-RAY IMAGING EXAMINATION AND CT SYSTEM - 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. | 05-17-2012 |
20130121555 | RECONSTRUCTION OF IMAGE DATA - 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. | 05-16-2013 |