Abstract: The invention concerns an X-ray examination device, including an X-ray source and an X-ray detector, for forming an X-ray image of an object, an X-ray filter, arranged between the X-ray source and the X-ray detector, and adjusting circuit, connected to the X-ray filter for adjusting it. The adjusting circuit comprises a graphics device, cursor control for defining a region of interest in an image of the object, displayed on the graphics device, and image-processing unit, connected to the X-ray filter, for calculating the region of interest and adjusting the filter accordingly. The X-ray filter includes filter elements having an X-ray absorptivity which can be adjusted by controlling a quantity of X-ray absorbing liquid within the individual filter elements. The filter elements are capillary tubes, and adjusting circuit applies electric voltages to the individual capillary tube for controlling the quantity of X-ray absorbing liquid in the tube.

Abstract: A method for the acquisition of a set of projection images for the reconstruction of a three-dimensional image data set of an object to be examined that is arranged in an examination zone, said acquisition being performed by way of an X-ray device that includes an X-ray source and an X-ray detector, said X-ray source being guided along a trajectory around the examination zone, said trajectory being situated essentially on a spherical surface, in order to acquire the projection images. In accordance with the invention the trajectory is configured in such a manner that the X-ray source can continuously follow the trajectory in order to acquire the set of projection images and that not all points of the trajectory are situated in a common plane. This enables fast acquisition of a set of projection data that enables an exact reconstruction of the object to be examined. The invention also relates to a corresponding X-ray device.

Abstract: The invention relates to a method of deriving time-averaged moments of a convolution profile from dynamic input and arrival profiles. A convolutive relation exists between the arrival profile and the input profile. According to the invention the time-averaged moment of the convolution profile is calculated from time-averaged moments of the dynamic input and arrival profiles. The method is used notably for the study of perfusion effects by means of magnetic resonance imaging.

Abstract: A window transparent to electron rays is provided which includes a foil which is transparent to electron rays and an element for supporting a peripheral region of the foil in an operational state. The element is made from a material having a greater linear thermal expansion coefficient than the foil material. The window transparent includes an intermediate layer between the foil and a retaining element. The retaining element acts as a support element and consists of a material having a linear thermal expansion coefficient which is equal or similar to the linear thermal expansion coefficient of the foil material and smaller than the linear thermal expansion coefficient of the material of the retaining element over a processing temperature range. A method of manufacturing a window which is transparent to electrons and an X-ray device with a window transparent to electrons are also provided.

Abstract: A magnetic resonance imaging method is proposed wherein the MR signal acquisition is performed by separate scanning of central (40) and peripheral (70) sectors. Central and peripheral sectors are selected in an individual plane in the k-space and optionally an intermediate sector (50) between the peripheral and central sectors is also selected. The center (O) in the k-space in the individual plane at issue is situated within the central sector. The scanning of the k-space commences outside the center of the k-space and before or during increasing contrast. Preferably, the scanning is timed such that the center of the k-space is reached at maximum contrast (MR angiography) or at the value zero of the longitudinal magnetization (MR inversion recovery). The central sector is advantageously scanned in a stochastic order. The peripheral sector may be scanned along a spiral-shaped trajectory, radial trajectories or along high-low ordered lines.

Abstract: The invention relates to a method enabling the localization of objects, for example surgical instruments, in interventional radiology. The method utilizes the known geometrical shape of the object to be localized in order to simulate projections therefrom for comparison with real projection images. Optimum correspondence between simulation and real image yields the desired object position and object orientation. The invention is based on digital image processing and can be used in conjunction with customary radiological diagnostic apparatus such as C-arm fluoroscopy apparatus, computed tomography apparatus or magnetic resonance tomography apparatus. Objects to be localized can be provided with markers whose spatial position yields an unambiguous projection image.

Abstract: The invention relates to an image processing method for noise reduction in a sequence of noisy original images representing a threadlike structure moving on a background, said method comprising: an acquisition of the digital pixel value at a current pixel location in a first and a second successive original image of the sequence, an extraction of the thread-like structure for providing first and second binary mask image pixel values at said location from said first and second original image, spatial and time-filtering of the pixel value of the second original image, and a pixel value selection based on said binary mask image pixel values for providing respectively, as a finally filtered pixel value, either the spatially or time-filtered pixel value respectively, as a threadlike structure filtered or a background pixel value. The invention also relates to a system and an apparatus for carrying out the method.

Abstract: The invention relates to an MR method in which a navigator pulse is generated to excite a nuclear magnetization in a spatially limited volume by at least one RF pulse and at least two gradient magnetic fields having gradients which extend differently in respect of time and space. After the navigator pulse excitation, at least one MR signal is received from the volume in conjunction with a further gradient magnetic field for evaluation. In order to enhance the navigator pulse, a variation in time is imposed on the gradient magnetic fields in order to generate at least two MR signals which correspond to an excitation in the k space along mutually offset trajectories. The MR signals are combined.

Abstract: A method of performing bone densitometry, utilizing a dual-energy method, wherein the surrounding soft tissue in the volume of interest is accurately eliminated from the transmission images by means of a calibration procedure. The method utilizes an X-ray apparatus with a two-dimensional X-ray detector so as to perform data acquisition during one run.

Abstract: An image processing method and an X-ray apparatus in which a thread-like structure represented on the background in a noisy digital original image is extracted. Original image data is acquired and reduced using a transformation operation so as to provide a reduced image. The most probable locations of guide-wire points in the reduced image are selected by selecting at each point the direction of the guide-wire which provides the best match with one of several predetermined regularly oriented directions and by probing the contrast around and in the selected directions and then probing the contrast around selected locations in the original image corresponding to the selected location of points in the reduced image. Then, the points which satisfy a contrast condition are extracted and the points which also satisfy a connectivity criterion in the reduced image are connected and these points are extracted as guide-wire points of the original image.

Abstract: An X-ray device for the formation of slice images of an object to be examined including an X-ray source, an X-ray detector, a transport device for moving the object during the acquisition of a series of X-ray projection images of the object in a movement plane situated parallel to the imaging plane, and a control device for controlling the acquisition of the X-ray projection images and the transport device. Slice images of the object are formed from the X-ray projection images by a tomosynthesis method.

Abstract: A method for identifying an optimum motion vector for a current block of pixels in a current picture in a process for performing motion estimation. The method is implemented by evaluating a plurality of motion vector candidates for the current block of pixels by, for each motion vector candidate, and calculating an error value that is representative of the differences between the values of the pixels of the current block of pixels and the values of a corresponding number of pixels in a reference block of pixels. While evaluating each motion vector candidate, the error value is checked, preferably at several points, while calculating the error value, and the evaluation is aborted for that motion vector candidate upon determining that the error value for that motion vector candidate exceeds a prescribed threshold value. The motion vector candidate that has the lowest calculated error value is selected as the optimum motion vector for the current block of pixels.

Abstract: An option is selected from a plurality of options by selecting a soft key from a plurality of displayed soft keys, each corresponding with a respective one of the options. The soft keys are displayed as a number of distinguishable groups of soft keys. A user first selects a particular group of soft keys. Then the soft keys are related to the hard keys of an input device on the basis of the relation of the soft key to its group and of the hard key to the input device respectively. Pressing a particular hard key results in the selection of the thus related soft key. The number of hard keys is equal to the number of soft keys in a group, rather than equal to the total number of soft keys.

Abstract: The invention relates to an X-ray examination apparatus which includes an X-ray source, an X-ray detector, absorption means arranged between the X-ray source and the X-ray detector, a control unit for adjusting the absorption degree of the absorption means, an image processing unit and a display unit. In order to perform an automatic adjustment of the absorption means, the absorption degree therein is optimized in dependence on user-specific parameters (r) and/or apparatus-specific parameters (s) and/or structure parameters (C) and/or parameters (r) classifying the subject matter of the image.

Abstract: The invention relates to an ultrasonic diagnostic imaging method for determining propagation parameters of transient shear wave front, comprising steps of forming transient shear waves in a tissue (5), acquiring ultrasonic image data (S,S*) of the tissue, along image lines (l), during a time delay (TSW) for a transient shear wave front to propagate over a depth (z) in said tissue, estimating the tissue velocity (V) for each line, constructing a tissue velocity image sequence [I(V)] from the ultrasonic data (S,S*) and the tissue velocities (V) on the lines, and deriving the velocities (CSW) of the shear wave front at instants of the sequence. Tissue parameters such as elasticity are then calculated from said front velocity. The invention also relates to an ultrasonic diagnostic imaging system having processing means (100, PROCESSING1, PROCESSING2) for carrying out this method. The processing means may be a computer program product having instruction to this end.

Abstract: The invention relates to a power supply for X-ray generators which includes at least one inverter, at least one transformer and at least one voltage cascade for generating a supply voltage for an X-ray tube. In order to increase the output power that can be achieved while ensuring at the same time a comparatively low weight and a small ripple or output capacitance, the voltage cascade is configured in respect of its capacitances and the stray inductance of the transformers in such a manner that it can operate in the resonance mode under appropriate control of the inverter. For said features it is particularly beneficial to use a two-phase or three-phase configuration which can be integrated with an X-ray system so as to form a compact tank generator.

Abstract: The reconstruction in Cone-beam CT scanner requires a high accuracy of the tabletop (1) position determination. In sequential as well as in helical acquisitions projection data (20) from different tabletop (1) positions are combined. Additional position markers, manufactured as insertions (10) of a contrast material relative to the material of the tabletop (1), are introduced into the tabletop (1). These insertions (10) allow the determination of the true position of the tabletop (1) from projection data. This information can be used to either control the scanner mechanics or as a correction information for the reconstruction process.

Abstract: An ultrasound system that performs image processing in the digital domain, including CW Doppler. The ultrasound system is provided with a transducer having a plurality of elements and an ultrasound receiver with a plurality of channels. Each channel receives an analog echo signal and outputs a digital representation of the analog echo signal using an A/D converter capable of converting a signal with a dynamic range of at least 154 dB.

Abstract: A magnetic resonance imaging system is provided with a system of emission antennas,: for example, emission coils, for generating RF excitation pulses. The RF excitation pulses generate magnetic resonance signals from an object to be examined. The system of emission antennas has a spatially inhomogeneous emission profile. The inhomogeneous emission profile is used for the partial spatial encoding of the magnetic resonance signals in addition to the encoding on the basis of magnetic gradient fields.

Abstract: A medical image management system including an image archive server for storing image datasets received from a plurality of image acquisition computers and a plurality of display stations for displaying requested image datasets retrieved from the image archive server is provided with an authentication and security system which includes an authentication server for maintaining and storing hashes and timestamps, and for providing hash, timestamp pairs in encrypted form in response to requests from display stations. The image acquisition computers are configured for computing hashes and providing them and image dataset identifiers to the authentication server, receiving timestamps from the authentication server which are then inserted in the image datasets, and storing the image datasets in the image archive server.