Siemens Aktiengesellschaft

Bernhard Scholz

Ernst-Peter Rührnschopf

Jan Boese

Thomas Mertelmeier

Philipp Bernhardt

Christopher Rohkohl

Michael Zellerhoff

Wolfgang Härer

Alois Nöttling

Thomas Flohr

Michael Maschke

Herbert Bruder

Klaus Klingenbeck-Regn

Frank Dennerlein

Günter Lauritsch

Joachim Hornegger

Benno Heigl

Stefan Schaller

Bernd Ohnesorge

Thomas Brunner

Klaus Klingenbeck

Bernd Schreiber

Karl Wiesent

Stefan Hoppe

Holger Scherl

Norbert Karl Strobel

Ernst Peter Rührnschopf

Ernst-Peter Rühmschopf

Roselle Anderson

A method for acquiring a 3D image dataset for an image object based on a plurality of 2D image datasets relating to the image object is proposed. A scattered radiation is taken into account in an acquisition operator used in the method for the optimum reconstruction of the 3D image dataset. The acquisition operator should be as close as possible to the real mapping operator.

Method for acquiring a 3D image dataset for an image object

An interpolation of data values is performed during the acquisition of a 3D image dataset which is free of traces of a metal object imaged in the underlying 2D image datasets. A target function is defined into which data values of the 3D image dataset that are dependent on said substitute data values are incorporated following preprocessing. The substitute data values are then varied iteratively until the value of the target function satisfies a predetermined criterion. Residual artifacts that still persist following the interpolation can thus be effectively reduced.

Method for acquiring a 3D image dataset freed of traces of a metal object

A method is provided for supplying a 3D X-ray image data record for a moving object. The said object contains highly X-ray radiation-absorbent material. A correction is made in respect of the highly absorbent material in 2D forward projections obtained from a 3D-X-ray image data record. The forward projections are calculated using 3D motion fields, which are derived from original 2D X-ray image data records.

Method for supplying a 3D X-ray image data record for a moving object with highly absorbent material

A method for reconstruction of a three-dimensional image data set from projection images of an object captured with an X-ray device from different projection angles is proposed. At least one sub-area of the object is outside the coverage of the X-ray device, or as a result of strong attenuation by a metal so that no projection data is present in the sub-area. Filter lines are determined n the projection images. A first local transformation is performed along the filter lines on the projection images. The missing projection data on the transformed projection data is augmented. A non-local transformation is performed on the transformed projection data for determining of filtered, augmented projection data. The non-local transformation is different from a ramp filter which is created by the first local transformation and the non-local transformation. The three-dimensional image data set is determined by back-projection of the filtered, augmented projection data.

Method for reconstruction of a three-dimensional image data set and x-ray device

The invention relates to a method and a device for increasing contrast in medical images generated by an imaging system featuring an x-ray source and a detector. The detector detects x-rays of the x-ray source and converts image signals from the x-rays. The image signals are transferred to a control and processing unit for processing. Deconvolution of the image signals is carried out by application of an inverse modulation transfer function modified by a regularization. At least a volume image can be reconstructed from the deconvolved image signals.

Contrast increase in X-ray projection images and/or in tomographically reconstructed volumes by deconvolution of the projection images

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

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 provisional three-dimensional reconstruction of an examination object is determined based on two-dimensional original projection images. Provisional metal volumes are determined on the reconstruction by segmentation and mapped into the original projection images to define provisional metal areas. Edge points on edge zones of the provisional metal areas are selected. Data values of the original projection images within the provisional metal areas are modified as a function of data values of the selected edge points to determine modified projection images. Differential images are determined based on the original projection images and the corresponding modified projection images. Definitive metal areas are determined in the differential images by segmentation. The differential images are added to the modified projection images with the definitive metal areas deducted. A definitive three-dimensional reconstruction of the examination object is determined based on the modified projection images including the added differential images.

Method for determining a three-dimensional reconstruction of an examination object

A method is claimed for correcting truncation artifacts in a tomography method, wherein internal checkpoints having a low level of attenuation are selected within the projection image and external checkpoints are defined by extrapolation based on the internal checkpoints. An adaptation function is then tailored to the internal checkpoints and the external checkpoints. This allows truncation artifacts to be effectively suppressed during the reconstruction of sectional images.

Method for correcting truncation artifacts

The invention relates to a method for beam hardening correction in medical image. Beam hardening within the context of medical imaging projection image profiles are split up into a basic profile which is assigned to a homogeneous object area and into a detailed profile which is assigned to an inhomogeneous object area. On the basis of the basic profile and of the difference profile the mass occupancy of the different components in the object to be examined can be approximately determined. On the basis of the approximately determined mass occupancy the correction of the beam hardening can then be performed directly on the projection data.

Method for hardening correction in medical imaging

The invention relates to a method for speeding up the scattered radiation correction in a computed tomography system with a radiation source and a detector constructed in large-area format with a number of rows of detectors, by which an object is scanned from numerous projection angles, uses the measured values for the attenuation of the radiation in generating projection data which is postprocessed for the purpose of reconstructing tomographic views, in doing which a beam hardening correction is applied directly to the projection data, whereby according to the invention the scattered radiation correction is also applied directly to the projection data.

Method for speeding up the scattered radiation correction in a computed tomography system

The invention relates to a method for combined bone hardening and scattered radiation correction in X-ray computed tomography of a heterogeneous object with a CT system comprising an X-ray source moved around an object, a flat detector with a large number of distributed detector elements which detect measuring beams from a focal point of the X-ray tube, and a control and arithmetic-logic unit&#x2014;by iterative reconstruction and segmented vectorial reprojection calculation, wherein a scattered radiation correction and a radiation hardening correction are carried out in each iteration cycle for at least two different material components of the object being examined. The invention also relates to an X-ray CT system for carrying out this method.

Method for combined bone hardening and scattered radiation correction in X-ray computed tomography

The invention relates to an angiographic x-ray diagnostic device for rotation angiography with an x-ray emitter which can be moved on a circular path about a patient located on a patient support table, with an image detector unit which can moved on the circular path facing the x-ray emitter, with a digital image system for recording a plurality of projection images by means of rotation angiography, with a device for image processing, by means of which the projection images are reconstructed into a 3D volume image, and with a device for correcting physical effects and/or inadequacies in the recording system such as truncation correction, scatter correction, ring artifact correction, correction of the beam hardening and/or of the low frequency drop for the soft tissue display of projection images and the 3D volume images resulting therefrom.

Angiographic x-ray diagnostic device for rotation angiography

A measurement system for examining a section of tissue on a patient in which electric current and/or voltages are applied to a patient in at least one location and are measured on the section of tissue to be examined by at least one electrode of a contact surface of the measurement system. As a result, conclusions can be drawn about the interior of the section of tissue to be examined. The electrode is at least partially surrounded by a conductor element for contacting with a potential which deviates from that of the conductor element.

Measurement system for examining a section of tissue on a patient and the use of a measurement system of this type

To enable an artifact free reconstruction even in the case of large regions of interest and with scanning paths of below 360&#xb0;, provision is made for a method, with which a three-dimensional image volume is reconstructed from a number of two-dimensional projection images of a region of interest, which were recorded about the region of interest during a rotation of a recording system, comprising an x-ray source with a focal point and a detector, by calculating the gray scale values of the voxels of the image volume by back projection of the projection images, with which each two-dimensional projection images is composed in each instance from at least two individual projection images to form an extended two-dimensional projection image, with the respectively at least two individual projection images being recorded with a constant relative position between the focal point and the region of interest.

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Heroldsbach, Germany

Bernhard Scholz