Siemens Aktiengesellschaft

Wolfgang Härer

Ernst-Peter Rührnschopf

Michael Zellerhoff

Holger Kunze

Bernhard Scholz

Jan Boese

Peter Speier

Karl Stierstorfer

Marcus Pfister

Thomas Mertelmeier

Martin Hoheisel

Karl Barth

Alois Nöttling

Karl Wiesent

Dr Klaus Klingenbeck-Regn

In a computer tomography method an object region of the object being examined is determined in that projection beams that are linked with maximum attenuation are sought in cropped projection images. A central point of the object region is then determined and the object sections associated with the projection beams plotted on the central point. The object region can be at least approximately determined using the end points of the object sections.

Computer tomography method for determining an object region with the aid of projection images

Method for three-dimensional representation of arteries and/or veins in an object by a tomography x-ray device is proposed. A mask pass with N projections at N angular positions without contrast agent is implemented. A first filler pass with M projections at M angular positions after injecting a contrast agent, where M&#x3c;N is implemented, followed by a second filler pass with N&#x2212;M projections at N&#x2212;M angular positions. A composite three-dimensional volume data record is reconstructed from an intermediate data record determined from the mask pass, the first and the second filler pass. A reprojection for arteries and/or for veins is calculated by reprojection of the first filler pass and/or of the second filler pass from the composite three-dimensional volume data record. A three-dimensional volume data record for arteries and/or for veins is calculated by weighting the composite three-dimensional volume data record taking into account the respective measured and calculated projection images.

Method and device for the separate three-dimensional representation of arteries and veins in an examination object and device

The invention relates to a method for reducing image noise in the context of capturing at least one radiation-based image of a region of interest using two different radiation spectra, in particular two different x-ray radiation spectra, comprising the following steps: capturing raw images of the region of interest using the two different radiation spectra with in each case mutually paired measured values; and to separate different materials in the region of interest, applying to the captured raw images at least one inversion operator with integrated noise filtering, said operator describing a transition from a measured value pair to an assigned reconstruction value pair.

Method for reducing image noise in the context of capturing an image using two different radiation spectra

A method for creating material-selective volume images of various material components of an object to be examined is proposed. The method is based on multi-spectral projected images captured from various directions of projection, the images being captured using an X-ray machine, and makes it possible to quantitively exactly determine the material-selective volume images by way of iteration.

Method for creating material-selective volume images

A number of two-dimensional projection images of a three-dimensional examination object are assigned image times and imaging parameters. The projection images are combined into reconstruction groups including projection images with image times specifically assigned or within a time interval specific to the reconstruction groups. The reconstruction groups are determined in such a way that three-dimensional reconstructions of the examination object with direction-dependent local resolution can be determined based on the projection images of the reconstruction groups; it is not possible to determine three-dimensional reconstructions of the examination object with direction-independent local resolution. Three-dimensional reconstructions of the examination are determined based on the projection images of the reconstruction groups. Reconstruction times are determined based on the image times assigned to the projection images of the reconstruction groups and assigned to the three-dimensional reconstructions. Further analyses are performed as a function of the temporal sequence of the three-dimensional reconstructions.

Analytical method for a number of two-dimensional projection images of a three-dimensional examination object

The invention relates to a computed tomography method. The airgap associated with a projection direction is determined by determining, in the projection images, edge pixels which map object edges on a detector. By back-projecting the edge pixels in an object image space it is possible to determine an envelope polygon for an outline contour of the examination object. The width of the airgap associated with a specific projection direction can then be determined on the basis of the envelope polygon. Exact knowledge of the current airgap serves to improve the scattered radiation correction.

Computed tomography method

The invention relates to a method for a three-dimensional representation of a moving structure by a tomographic method, in which during one recording pass a series of projection recordings is registered by an imaging unit at different recording angles between a start position and an end position, it being possible to reconstruct three-dimensional image data from the projection recordings with the following steps: a) generation of tomosynthesis projection recordings along a tomosynthesis scanning path; b) interpolation of the data of the tomosynthesis projection recordings in accordance with an interpolation algorithm in order to generate a projection data set; c) use of a tomosynthesis reconstruction method on the projection data set in order to generate a tomosynthesis volume image; d) repetition of steps b) and c) for all times of interest, and e) display of tomosynthesis representations from the tomosynthesis volume images.

Method for the three-dimensional representation of a moving structure by a tomographic method

In a known type of tomosynthesis x-ray source and x-ray detector are linearly moved and x-rays images are taken for a large number of positions, the images being reconstructed to give a 3D image record. According to the invention x-ray source and x-ray detector are swiveled and a sequence of x-rays is subsequently taken again, x-ray source and x-ray detector again being moved in a straight line. One drawback of simple tomosynthesis with movement in a straight line is suppressed thereby, the drawback being that the quality of reconstruction is particularly poor in a certain direction.

Method for providing 3D image data and system for taking x-ray images

The invention relates to a method for generating tomographical recordings of a partially cyclically moving examination object by a tomography system and a tomography system, comprising the steps of: a spatial scanning of the examination object taking place using at least one detector, which generates detector output data; movement information of the moving subarea of the examination object being recorded during the scanning and being assigned to the detector output data or stored in a manner which correlates to the detector output data; and tomographical image data being reconstructed from the measured detector output data in a number of iteration steps. The invention is characterized in that iteration takes place in at least two iteration stages, with data records being used from the detector output data of different cycle phase regions in at least two iteration stages.

Method for generating tomographical recordings of a partially cyclically moving examination object

A method is disclosed for reconstructing a tomographic representation of an object from projection data off a moving radiation source through this object onto a detector, filtering and back projection of the projection data being executed in the reconstruction. In an embodiment of the method, by using at least one identical spatial arrangement of the radiation source, the detector and a test object instead of the object to be scanned, there is determined by test projections and an iterative reconstruction technique, a filter that in the given arrangement results in an optimum filtering and back projection of the projection data of the test object for the tomographic representation. Further, the object is scanned instead of the test object in the given arrangement and projection data are determined. Finally, the reconstruction of the tomographic representation is carried out using these projection data and the filter determined. Moreover, an embodiment of a tomography unit for carrying out this method is also disclosed.

Method and tomography unit for the reconstruction of a tomographic display of an object

In a method and MRI apparatus for the minimization of streak artifacts in modular k-space scanning in magnetic resonance imaging, an odd integer k-space scanning module number N=2n+1 is defined that defines the number of incrementally rotated repeated modules of the k-space scanning process, a slice selection gradient selects any slice in the range of the object to be examined, and data for all Nangle-oriented k-space scanning modules in the selected slice acquired such that each k-space scanning module has an azmuthal distance of from both adjacent projections, with the direction of the scanning of the adjacent k-space scanning modules alternating.

Growing community of inventors

Erlangen, Germany

Wolfgang Härer