Patent application number | Description | Published |
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 |
20090052611 | Method and x-ray computed tomography system for visualizing at least two types of cardiac tissue: Healthy tissue and diseased tissue - A method and an x-ray computed tomography system are disclosed for visualizing at least two different types of cardiac tissue, such as normally perfused tissue, hypoperfused tissue and scarred tissue. In at least one embodiment, this is done by use of an imaging tomographic recording technique with the aid of x-ray radiation, wherein at least one cardiac region of a patient is scanned by x-ray radiation which passes through a first grating for the passing-through x-ray radiation, designed as an absorption grating, prior to reaching the patient, and at least the locally caused phase-shifts of the x-ray radiation in the cardiac region are also made detectable by using a second grating for the passing-through x-ray radiation, designed as a phase grating, downstream of the patient in the emission direction, and the spatial distribution of these shifts is measured and reconstructed, wherein an average specific phase-shift value is assigned to each spatial unit, wherein each of the abovementioned tissue types are assigned to a region of a typical specific phase-shift value and at least one region assigned to a tissue type is optically highlighted in a view of the cardiac region. | 02-26-2009 |
20090052614 | Method for marking and visualizing an implant by way of an x-ray phase-contrast tomography examination and an implant - A method is disclosed for marking and visualizing an implant by use of an x-ray phase-contrast tomography examination. Further, an implant is also disclosed. In at least one embodiment, implants are used with specific characteristics which are as unambiguous as possible with regard to the phase shift generated by the implants in a phase-contrast tomography examination. In at least one embodiment, these specific characteristics can include the typical self-generated specific phase shift, typical differences in the specific phase-shift values, or typical spatial structures of materials with well-defined phase-shift values. | 02-26-2009 |
20090074139 | Method and an apparatus for detecting and localizing a metabolic marker - A method and an x-ray system are disclosed for detecting and localizing a metabolic marker. In at least one embodiment, the method includes creating at least one absorption x-ray view of a patient or of a first region of a patient; creating at least one phase-contrast x-ray view of the patient or of a second region of the patient, with a quasi-coherent x-ray radiation being generated for the phase-contrast measurement with the aid of an x-ray grating arranged between the x-ray source and the patient, and the spatially dependent phase shift of the x-ray radiation in the patient being made visible with the aid of at least one grating between the patient and a detector; superposing the at least one absorption x-ray view and the at least one phase-contrast x-ray view; wherein orientation based on anatomical features is carried out with the aid of the at least one absorption x-ray view, and a spatial distribution of the metabolic marker present in the body of the patient is determined by the at least one phase-contrast x-ray view. | 03-19-2009 |
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 |
20090141857 | Method for post-processing raw detector signals, a computer program product, a computer readible medium and a radiation detection device - 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. | 06-04-2009 |
20090161820 | Method for increasing the quality of computer tomographic recording series by projection data processing and CT system having a computation unit - A method is disclosed for increasing the quality of computer tomographic recording series, to a computation unit and to an X-ray CT system. An embodiment of the method includes scanning a subject over a period of time which makes it possible to record at least two temporally offset projection data sets of the same recording region; transforming the projection data sets into transformation data sets for at least two spatial frequency ranges; calculating temporal compensation values of the transformation data sets for some of the spatial frequency ranges and replacing the compensated values of the transformation data sets with the calculated compensation values in new transformation data sets, projection data of congruent rays always being compared; transforming the new transformation data sets back into new projection data sets; reconstructing image data sets on the basis of the new projection data sets and representing the image data sets. | 06-25-2009 |
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 |
20100045696 | Method for producing 2D image slices from 3D projection data acquired by means of a CT system from an examination subject containing metal parts - A method of at least one embodiment has three method sections. In the first method section, 3D projection data is generated by 3D scanning of the examination subject and first 3D image data is reconstructed therefrom by means of convolution back projection. In the second method section, the image artifacts present in the first 3D image data because of the metal parts are corrected via simple correction methods which produce at least a coarse reduction in the image artifacts involving a low degree of computational complexity. In the third method section, 2D image data is selected from the corrected 3D image data and made available. For image artifacts still contained in the 2D image data, more complex correction methods than in the second method section are used which permit effective elimination of the image artifacts. | 02-25-2010 |
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 |
20100091937 | X-RAY BEAM MODIFYING DIAPHRAGM AND DIAPHRAGM DEVICE - A diaphragm and diaphragm device for the specific manipulation of x-ray radiation that emanates from an x-ray focus of a CT apparatus and serves for scanning an examination subject, wherein the x-ray focus and the diaphragm arranged relatively near to the focus can be rotated together around a system axis (z-axis), and the diaphragm has movable diaphragm elements that dynamically adjust a diaphragm aperture (and therefore the spatial divergence of the x-rays passing through the diaphragm aperture). The diaphragm elements have a transmission factor for x-ray radiation that is different than zero. With such a diaphragm or diaphragm device the acquisition of the projection data necessary for the reconstruction of an artifact-free image of a region of interest (ROI) is possible with lower radiation exposure of the examination subject. | 04-15-2010 |
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 |
20100166277 | Method for noise reduction of CT images and image processing system - A method is disclosed for noise reduction of CT image data and an image processing system is disclosed. An object under examination is scanned and at least two CT image datasets are created, each being undertaken on the basis of a different x-ray generation process. Subsequently, the image datasets are split up into at least two split-up image datasets, with a lowest local frequency band and at least one high local frequency band. In at least one embodiment, this is followed by the determination of the noise in at least one of the image datasets for each x-ray spectrum and calculation of at least one new image dataset using an unchanged split-up image dataset in each case with the lowest frequency band and an image dataset created from a noise-minimized weighted combination of split-up image datasets, which originate from the scans with different x-ray energy spectrums. | 07-01-2010 |
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 |
20100195787 | METHOD AND DEVICE FOR GENERATING A CT IMAGE WITH A HIGH TIME RESOLUTION - 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. | 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 |
20100278411 | CONTRAST INTENSIFICATION OF CT IMAGES BY WAY OF A MULTIBAND FILTER - A method is disclosed for processing an output image of an examination object, with the output image having been reconstructed from measuring data acquired during a relative rotational movement between a radiation source of a computed tomography system and the examination object. An image frequency division of an output image takes place in at least a first and a second image. In at least one embodiment, the first image is changed by way of a first function, with the first function effecting a contrast intensification within the first image, and the changed first image and the second image are merged together. | 11-04-2010 |
20110007956 | SINOGRAM PROCESSING TO REDUCE METAL ARTIFACTS IN COMPUTED TOMOGRAPHY - A method is disclosed for reconstructing image data of an examination object from measurement data, wherein the measurement data was captured as projection data during a relative rotational movement between a radiation source of a computed tomography system and the examination object. In at least one embodiment, a first image is determined from the measurement data and pixel values of the first image are modified, by classifying the pixel values in at least three classes, a class pixel value being assigned to each class, and the pixels of the first image being allocated the respective class pixel value. Projection data is calculated from the thus modified first image. The calculated projection data is used to normalize the measured projection data. Values are modified in the normalized projection data and the thus modified normalized projection data is subjected to a processing that reverses normalization. Finally a second image is determined from the thus processed projection data. | 01-13-2011 |
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 |
20110064292 | SYSTEM AND METHOD FOR MULTI-IMAGE BASED VIRTUAL NON-CONTRAST IMAGE ENHANCEMENT FOR DUAL SOURCE CT - A method for enhancing a virtual non-contrast image, includes receiving a pair of dual scan CT images and calculating a virtual non-contrast image from the pair of CT images using known tissue attenuation coefficients. A conditional probability distribution is estimated for tissue at first and second points in each of the pair of CT images and the virtual non-contrast image as being the same type. A conditional probability distribution for tissue is estimated at the first and second points in each of the pair of CT images and the virtual non-contrast image as being of different types. An a posteriori probability of the tissue at the first and second points as being the same type is calculated from the conditional probability distributions, and an enhanced virtual non-contrast image is calculated using the a posteriori probability of the tissue at the first and second points as being the same type. | 03-17-2011 |
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 |
20110280458 | Method For The Reduction Of Image Artifacts, In Particular Of Metal Artifacts, In CT Image Data - A method is disclosed for the reduction of image artifacts, in particular metal artifacts, during the generation of computed tomography image data of an object. In at least one embodiment of the method, two CT image data sets are generated with different medium x-ray energies. By way of a weighted combination of the two CT image data sets, a new image data set is calculated. The weighting factor employed in the weighted combination is here selected in such a way that the image artifacts in the new CT image data set are significantly reduced compared with the image artifacts in the two original CT image data sets. In this way it is possible in a simple manner significantly to reduce in particular metal artifacts in CT images. | 11-17-2011 |
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 |
20120140893 | METHOD AND DEVICE TO DETERMINE THE VALUE OF AN X-RAY TUBE VOLTAGE - The value of a tube voltage of an x-ray tube, used to acquire x-ray projections of a patient in order to generate at least one image in each phase of a multiphase examination, is determined from a contrast-to-noise ratio that establishes the desired image quality of the image in each phase, and the tube current for each tube voltage for each phase is determined given a constantly maintained contrast-to-noise ratio for different tube voltages. For each phase, a value for the dose of x-ray radiation is defined for each different tube voltage and the associated determined tube current. From among the different tube voltages, a tube voltage is set that causes the total dose of x-ray radiation applied to the patient to be as low as possible for all phases of the examination. | 06-07-2012 |
20120140894 | METHOD AND X-RAY DEVICE TO DETERMINE THE VALUE OF THE TUBE VOLTAGE - In a method and x-ray device to determine the value of an x-ray tube voltage to generate at least one image of defined tissue to be examined, at least one provided parameter is used that establishes or describes the desired image quality; based on the dependency of the contrast of the defined tissue to be examined on the spectrum of the x-ray radiation or on the value of the tube voltage of the x-ray tube. The tube voltage is determined also based on a contrast-to-noise ratio that is constantly maintained under consideration of the aforementioned parameter such that the dose of x-ray radiation applied to the patient is optimally low upon setting the value of the tube voltage at the x-ray tube and the acquisition of at least one x-ray projection of the defined tissue. | 06-07-2012 |
20120201344 | METHOD AND X-RAY DEVICE FOR ADAPTING GREYSCALE WINDOWING - In a method and x-ray device to adapt the width and the position of a central value of a greyscale windowing for imaging with the x-ray device based on CT values determined with said x-ray device, the adaptation takes place within the scope of a determination and adjustment of an acquisition tube voltage of an x-ray tube of the x-ray device for an examination of a defined tissue of a patient, assuming a reference tube voltage for the examination of the defined tissue of the patient, and in which a width and position of a central value of the greyscale windowing that are associated with the reference tube voltage are automatically adapted to the acquisition tube voltage. | 08-09-2012 |
20130039556 | METHOD, COMPUTING UNIT, CT SYSTEM AND C-ARM SYSTEM FOR REDUCING METAL ARTIFACTS IN CT IMAGE DATASETS - A method is disclosed for reducing metal artifacts in CT image datasets. An embodiment of the method includes reconstructing a first CT image dataset with and a second CT image dataset without metal artifact correction, weighted summation of a high-pass-filtered first and a high-pass-filtered second CT image dataset plus a low-pass-filtered second CT image dataset, wherein the weightings are dependent on the proximity to metal in the CT image datasets. A computing unit, a CT system and a C-arm system designed to execute the method are also disclosed. | 02-14-2013 |
20130083989 | METHOD FOR PRODUCING A NOISE-REDUCED CT IMAGE DATA RECORD, COMPUTER SYSTEM, AND CT SYSTEM - A method is disclosed for producing a noise-reduced CT image data record by frequency band breakdown, a computer system for carrying out the method, and a CT system ( | 04-04-2013 |
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 |
20130259342 | METHOD FOR ITERATIVE IMAGE RECONSTRUCTION FOR BI-MODAL CT DATA - 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. | 10-03-2013 |
20140169649 | CT IMAGE RECONSTRUCTION WITH EDGE-MAINTAINING FILTERING - A method is disclosed for reconstructing image data of an examination object from measurement data, wherein the measurement data were captured previously during a relative rotational movement between a radiation source of a computed tomography system and the examination object. Filtered measurement data are calculated from the measurement data. First image data are calculated from the measurement data. Edge information is obtained from the first image data, wherein the edge information, depending on position, specifies strength and direction of edges within the first image data. New measurement data are calculated using the edge information by mixing the measurement data and the filtered measurement data and second image data are calculated from the new measurement data. | 06-19-2014 |