Abstract: A system and method of determining hemodynamic parameters of a patient is described. A background image data set is obtained prior to the administration of a contrast agent. A series of image data sets is obtained during the first passage of the bolus through a parenchymal volume. The pre-contrast-agent image is subtracted from image data sets obtained during the first passage of the contrast agent bolus, so that the amount of contrast agent in the volume may be determined. The time series of the amount of contrast agent is computed to determine the arterial input function (AIF) which may be used to determine a tissue impulse response, and hemodynamic parameters such as cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT).

Abstract: 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.

Abstract: There is described a method using an X-ray imaging unit, which has an arched support for the X-ray source and the X-ray detector. In the method, in a scan carried out by moving the support around an examination object a plurality of X-ray images of an area of interest are recorded using different projection angles, from which a three-dimensional image of the area of interest can be reconstructed. In this case the X-ray focus of the X-ray source is guided on a segment of a circular path of at least 180° around the examination object. In the case of a non-centric location of the area of interest, the support is rotated in such a manner prior to each of the X-ray imaging processes around an axis of rotation passing through the X-ray focus that the central ray of the X-ray beam for the X-ray imaging processes passes through the center of the area of interest.

Abstract: There is described a method for a separate three-dimensional representation of arteries and/or veins of a vascular system in an examination object by means of a tomography x-ray device with the following steps: Implementation of a mask pass of the x-ray device with N projections at N angular positions about the examination object without contrast agent; Implementation of a first filler pass of the x-ray device about the examination object with M projections at M of the N angular positions after injection of a contrast agent, where M<N; Implementation of a second filler pass of the x-ray device about the examination object with N-M projections at N-M of the N angular positions directly following the first filler pass; reconstruction of a composite three-dimensional volume data record from an intermediate data record, said intermediate data record being determined from the data records resulting from the mask pass, the first filler pass and the second filler pass by subtraction and combination; Calculation o

Abstract: The invention relates to a method for three-dimensional representation of a moving structure by a tomographical method. Projection images are recorded by an image recording unit during a rotational run from recording angles between a start angle and an end angle, with a three-dimensional image data reconstructed from the projection images, with a first perfusion measurement with a first contrast agent injection and a first rotational run and with a further perfusion measurement with a further contrast agent injection and a further rotational run, which is started after the preceding perfusion measurement has concluded, with the start time and/or the start angle of the additional rotational run deviating from one another in respect of the time of the contrast agent injection. The method enables a functional three-dimensional time-resolved imaging of perfusion processes with the aid of flexible C-arm x-ray devices, which allow a functional imaging in an interventional environment.

Abstract: A system and method of obtaining perfusion data for cerebral tissue is described. The system includes a C-arm X-ray device and a computing system configured to obtain sets of rotational projection X-ray data suitable for reconstructing 3D voxel data sets. A first data set is obtained of the patient, and then contrast material is injected into the vascular system to obtain a second 1 data set. A first voxel data set is subtracted from the second voxel data set, and the resultant data set is processed so as to segment the contrast-enhanced vasculature from the remaining data. The segmented voxels are subtracted from the resultant voxel data set, so as to yield a functional data set representing the difference between the attenuation of the tissues after administering contrast agent and the tissues prior to administering the contrast agent, without the contrast enhanced vasculature. The attenuation of the functional data set represents the perfusion or cerebral blood volume (CBV).

Abstract: There is described a method using an X-ray imaging unit, which has an arched support for the X-ray source and the X-ray detector. In the method, in a scan carried out by moving the support around an examination object a plurality of X-ray images of an area of interest are recorded using different projection angles, from which a three-dimensional image of the area of interest can be reconstructed. In this case the X-ray focus of the X-ray source is guided on a segment of a circular path of at least 180° around the examination object. In the case of a non-centric location of the area of interest, the support is rotated in such a manner prior to each of the X-ray imaging processes around an axis of rotation passing through the X-ray focus that the central ray of the X-ray beam for the X-ray imaging processes passes through the center of the area of interest.

Abstract: To enable an artifact free reconstruction even in the case of large regions of interest and with scanning paths of below 360°, 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.

Abstract: The invention relates to a method and a device for the separate three-dimensional representation of arteries and/or veins in a vascular system of the body by means of a C-arm biplanar system having two C-arms, which can each record a sequence of x-ray images from different projection angles during a mask or filler pass. With the filler pass, both C-arms record x-ray images, so that the x-ray images of the filler pass can be combined to form a first data record, which contains x-ray images from the arterial phase of the vascular contrasting and/or to form a second data record, which contains x-ray images from the venous phase of the vascular contrasting. This enables the arterial and venous phases to be reconstructed separately.

Abstract: 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.

Abstract: There is described a method for a periodic and three-dimensional representation of a periodically variable structure. A number of rotation images is generated for this purpose. The required rotations relating to the same event of the periodic process are started at intervals offset by a defined angle. From the rotation images, new image series are assembled with which three-dimensional representations relating to different phase ranges of the period are reconstructed.

Abstract: The invention is directed to a method and a device for separate three-dimensional presentation of arteries and/or veins of a vessel system in a part of the body of a vertebrate by a rotation computer tomography. A masking run of the tomograph is undertaken without contrast media around the part of the body. Then two filling runs with contrast media are executed, with the venous phase of vessel contrasting during the first filling run occurring during the arterial phase of vessel contrasting of the second filling run and vice-versa. The data from the first and second filling run is combined into data sets from the arterial or the venous phases of the vessel contrasting of the filling runs. The data of the masking run is subtracted from the combined data sets to obtain final data sets for a three-dimensional presentation of the arterial or the venous vessel system.

Abstract: 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.

Abstract: In a method for reconstruction of a three-dimensional image of an object scanned in linear or circular fashion in the context of a tomosynthesis. The object is transirradiated with X-rays from various projection angles &phgr; for the recording of the projection images, and the radiation exiting from the object is recorded by a detector that supplies digital output image signals. The output image signals representing the projection image data are supplied to a computer for image reconstruction. In the context of the reconstruction a filter is first produced, on the basis of the following steps: A 3D transmission function Hproj(&ohgr;x,&ohgr;y,&ohgr;z) is calculated from the recording geometry for the individual projection image recording and the back-projection of the individual projection images into the 3D reconstruction image volume. By approximation, the 3D transmission function Hproj(&ohgr;x,&ohgr;y,&ohgr;z) is inverted for the determination of an inversion function Hinv(&ohgr;x,&ohgr;y,&ohgr;z).