摘要:
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−α(Q(Pfk−p)+βR(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.
摘要:
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.
摘要:
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−α(Q(Pfk−p)+βR(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.
摘要:
An x-ray system is disclosed including a selector for finding an optimum combination between the contrast medium and the energy spectrum of an x-radiation for a scan to optimize the noise-to-contrast ratio. A method for creating X-ray images is also provided. The x-ray images are created with the aid of contrast media by taking into account an optimal combination between the contrast medium and the energy spectrum of an X-radiation used for a scan. A method for the use of a lanthanide-containing complex to produce a contrast medium for optimizing the combination between the contrast medium and the radiation to obtain a maximum contrast-to-noise ratio in an X-ray image is also provided.
摘要:
A method is disclosed for generating CT displays in x-ray computed tomography with contrast medium support, the blooming effect being reduced by decomposing an object into three material components when scanning the object with two different energy spectra, and determining a first component and determining the material thickness thereof by segmentation. Subsequently, in at least one embodiment, the two other material components and their material thicknesses are determined on the basis of the measured attenuation values of the two spectra for each beam, and virtual absorption data with virtual absorption coefficients are constructed for the individual material components from the material strengths thus known for the different material components, and are used to reconstruct the CT display.
摘要:
A method is disclosed for calculating absorber-specific weighting coefficients and a method is disclosed for improving a contrast-to-noise ratio, dependent on an absorber, in an x-ray image of an object to be examined produced by an x-ray machine. A weighted summation of detector output signals from different energy windows of an energy-selector detector are used to improve the contrast-to-noise ratio as a function of the absorber.
摘要:
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.
摘要:
A method is for determining a parameter in an image area as a measure of a homogeneity of a substance in an object, and to a method for segmenting a substance in an image that uses the parameter as an additional segmentation criterion. In the method, at least two X-ray images are acquired in relation to different energies E1, E2 of an X-radiation, and the parameter is determined from the statistical distribution of attenuation values Di(E1),Di(E2) where i=1, . . . , N in the image area such that faulty classifications can be avoided in a simple way during the segmentation.
摘要:
An x-ray system is disclosed including a selector for finding an optimum combination between the contrast medium and the energy spectrum of an x-radiation for a scan to optimize the noise-to-contrast ratio. A method for creating X-ray images is also provided. The x-ray images are created with the aid of contrast media by taking into account an optimal combination between the contrast medium and the energy spectrum of an X-radiation used for a scan. A method for the use of a lanthanide-containing complex to produce a contrast medium for optimizing the combination between the contrast medium and the radiation to obtain a maximum contrast-to-noise ratio in an X-ray image is also provided.
摘要:
A method is for determining a parameter in an image area as a measure of a homogeneity of a substance in an object, and to a method for segmenting a substance in an image that uses the parameter as an additional segmentation criterion. In the method, at least two X-ray images are acquired in relation to different energies E1, E2 of an X-radiation, and the parameter is determined from the statistical distribution of attenuation values Di(E1),Di(E2) where i=1, . . . , N in the image area such that faulty classifications can be avoided in a simple way during the segmentation.