Abstract: The present invention relates to a method (1), resp. a device, system and computer-program product, for material decomposition of spectral imaging projection data. The method comprises receiving (2) projection data acquired by a spectral imaging system and reducing (3) noise in the projection data by combining corresponding spectral values for different projection rays to obtain noise-reduced projection data. The method comprises applying (6) a first projection-domain material decomposition algorithm to the noise-reduced projection data to obtain a first set of material path length estimates, and applying (7) a second projection-domain material decomposition algorithm to the projection data to obtain a second set of material path length estimates. The second projection-domain material decomposition algorithm comprises an optimization that penalizes a deviation between the second set of material path length estimates being optimized and the first set of material path length estimates.

Abstract: A spectral X-ray imaging system (100) includes an X-ray source (110) and an X-ray detector (120) that are mounted to a support structure (150). The support structure (150) is configured to rotate the X-ray source (110) and the X-ray detector (120) around two or more orthogonal axes (A-A?, B-B?). One or more processors (130) are configured to cause the system (100) to perform operations that include: generating a spectral image based on the spectral image data; and identifying, in the spectral image, a position of a first fiducial marker (180i) comprising a first material, based on a first X-ray absorption k-edge energy value (190i) of the first material.

Abstract: The present invention relates to a rotary anode X-ray source. In addition to a primary cathode of a rotary anode X-ray tube, an auxiliary cathode is provided in the rotary anode X-ray tube. Electrons from the auxiliary cathode are focused into an area on the anode, from which X-rays cannot enter the used X-ray beam generated by the primary cathode. An emission current controlling device is used to control the electron emission of the auxiliary cathode. Thus, the voltage down-ramp for dual energy scanning is kept constant even though the primary X-ray output changes for the sake of dose modulation or during a transient of the primary electron current.

Abstract: A radiation detector (100) adapted for detecting leakage currents is disclosed and comprises a direct conversion material (101) for converting incident radiation, at least one first electrode (108) and a plurality of second electrodes (103) connected to surfaces of the direct conversion material (101) for collecting each generated charges upon application of an electric field, at least one current measurement device (201), and a plurality of signal processing chains (210, 220, 230). Each signal processing chain comprises a readout unit (215, 216, 217, 218, 219) for discriminating between energy values with respect to the incident radiation, and a switching element (214) for sending signals on a first signal path (2141) electrically connecting one of the plurality of second electrodes with the readout unit, or on a second signal path electrically connecting the one of the plurality of second electrodes with an input to one of the at least one current measurement devices.

Abstract: The invention relates to an image reconstruction apparatus comprising a detector value providing unit for providing detector values for each detector element of a plurality of detector elements forming a radiation detector and for each energy bin of a plurality of predefined energy bins, a correlation value providing unit for providing correlation values, wherein a correlation value is indicative of a correlation of a detector value detected by a detector element in an energy bin with at least one of a) a detector value detected by another detector element in the energy bin, b) a detector value detected by another detector element in another energy bin, and c) a detector value detected by the detector element in another energy bin, and a spectral image reconstruction unit for reconstructing a spectral image based on the detector values and the correlation values.

Abstract: A method for operating a cardiac CT imaging system (200) in coronary CT with prospective electrocardiography-triggering of the imaging system (200) is proposed. The method comprises the steps of determining a plurality of R-peak times (ti) from a dataset of electrocardiography data, determining a variability of a heart rate by statistically analyzing the determined R-peak times (ti), and automatically adjusting an acquisition time period (?Tac) of the CT imaging system (200) for acquiring projection data based on the determined variability of the heart rate.

Abstract: Motion compensated reconstruction is currently not well-suited for reconstructing the valve, the valve leaflets and the neighboring vascular anatomy of the heart. Blurring of the valve and the valve leaflets occurs. This may lead to wrong diagnosis. A new approach for motion compensated reconstruction of the valve and the related anatomy is presented in which an edge-enhancing step is performed to suppress blurring.

Abstract: A medical imaging system (200) includes a masking unit (234), an image registration unit (238), a motion estimator (240) and a motion compensating reconstructor (244). The masking unit constructs a mask for each reconstructed volumetric phase image of a plurality of reconstructed volumetric phase images that masks portions of a corresponding image external to an anatomical model fitted to a segmented at least one anatomical structure, 5 wherein the plurality of reconstructed volumetric phase images include a target phase and a plurality of temporal neighboring phases reconstructed from projection data. The image registration unit registers the masked reconstructed volumetric phase images. The motion estimator estimates motion between the target phase and the plurality of temporal neighboring phases according to the model based on the registered masked reconstructed 10 volumetric phase images.

Abstract: The present invention relates to an anti-scatter grid (ASG) assembly comprising a first and a second grid, wherein the second grid is arranged on top of the first grid and comprises a lateral shift. The lamella thickness of the first grid is smaller than the lamella thickness of the second grid. The present invention further relates to a detector arrangement comprising a pixel detector and an ASG assembly arranged on top of the pixel detector.

Abstract: A radiation detector (100) adapted for detecting leakage currents is disclosed and comprises a direct conversion material (101) for converting incident radiation, at least one first electrode (108) and a plurality of second electrodes (103) connected to surfaces of the direct conversion material (101) for collecting each generated charges upon application of an electric field, at least one current measurement device (201), and a plurality of signal processing chains (210, 220, 230). Each signal processing chain comprises a readout unit (215, 216, 217, 218, 219) for discriminating between energy values with respect to the incident radiation, and a switching element (214) for sending signals on a first signal path (2141) electrically connecting one of the plurality of second electrodes with the readout unit, or on a second signal path electrically connecting the one of the plurality of second electrodes with an input to one of the at least one current measurement devices.

Abstract: An imaging method includes obtaining projection data for a helical scan of a subject. The method further includes reconstructing, for a particular time and image slice location of interest, a first temporal motion state image at an earlier time on the detector array and offset from the central row in a first direction with projection data from a first to subset of detector rows, and reconstructing, for the particular time and image slice location, a second temporal motion state image at a later time on the detector array and offset from the central row in a second direction with projection data from a second different subset of detector rows. The method further includes estimating a distortion vector field between the first and second temporal motion state images, and constructing motion compensated volu-metric image data with a motion compensated reconstruction algorithm using the distortion vector field to compensate for arbitrary motion.

Abstract: An imaging system includes radiation source that emits radiation that traverses an examination region and a portion of a subject therein and a detector array that detects radiation that traverses the examination region and the portion of the subject therein and generates a signal indicative thereof. A volume scan parameter recommender recommends at least one spectral scan parameter value for a volume scan of the portion of the subject based on a spectral decomposition of first and second 2D projections acquired by the radiation source and detector array. The first and second 2D projections have different spectral characteristics. A console employs the recommended at least one spectral scan parameter value to perform the volume scan of the portion of the subject.

Abstract: Motion compensated reconstruction is currently not well-suited for reconstructing the valve, the valve leaflets and the neighboring vascular anatomy of the heart. Blurring of the valve and the valve leaflets occurs. This may lead to wrong diagnosis. A new approach for motion compensated reconstruction of the valve and the related anatomy is presented in which an edge-enhancing step is performed to suppress blurring.

Abstract: An imaging system includes a radiation source (108) configured to rotate about an examination region (106) and emit radiation that traverses the examination region. The imaging system further includes an array of radiation sensitive pixels (112) configured to detect radiation traversing the examination region and output a signal indicative of the detected radiation. The array of radiation sensitive pixels is disposed opposite the radiation source, across the examination region. The imaging system further includes a rigid flux filter device (130) disposed in the examination region between the radiation source and the radiation sensitive detector array of photon counting pixels. The rigid flux filter device is configured to filter the radiation traversing the examination region and incident thereon. The radiation leaving the rigid flux filter device has a predetermined flux.

Abstract: The invention relates to an image reconstruction apparatus comprising a detector value providing unit for providing detector values for each detector element of a plurality of detector elements forming a radiation detector and for each energy bin of a plurality of predefined energy bins, a correlation value providing unit for providing correlation values, wherein a correlation value is indicative of a correlation of a detector value detected by a detector element in an energy bin with at least one of a) a detector value detected by another detector element in the energy bin, b) a detector value detected by another detector element in another energy bin, and c) a detector value detected by the detector element in another energy bin, and a spectral image reconstruction unit for reconstructing a spectral image based on the detector values and the correlation values.

Abstract: An imaging system includes radiation source that emits radiation that traverses an examination region and a portion of a subject therein and a detector array that detects radiation that traverses the examination region and the portion of the subject therein and generates a signal indicative thereof. A volume scan parameter recommender recommends at least one spectral scan parameter value for a volume scan of the portion of the subject based on a spectral decomposition of first and second 2D projections acquired by the radiation source and detector array. The first and second 2D projections have different spectral characteristics. A console employs the recommended at least one spectral scan parameter value to perform the volume scan of the portion of the subject.

Abstract: The present invention relates to an anti-scatter grid (ASG) assembly comprising a first and a second grid, wherein the second grid is arranged on top of the first grid and comprises a lateral shift. The lamella thickness of the first grid is smaller than the lamella thickness of the second grid. The present invention further relates to a detector arrangement comprising a pixel detector and an ASG assembly arranged on top of the pixel detector.

Abstract: An imaging system includes radiation source (106) that emits radiation that traverses an examination region and a portion of a subject therein and a detector array (114) that detects radiation that traverses the examination region and the portion of the subject therein and generates a signal indicative thereof. A volume scan parameter recommender (120) recommends at least one spectral scan parameter value for a volume scan of the portion of the subject based on a spectral decomposition of first and second 2D projections acquired by the radiation source and detector array. The first and second 2D projections have different spectral characteristics. A console (122) employs the recommended at least one spectral scan parameter value to perform the volume scan of the portion of the subject.

Abstract: The invention relates to an image generation apparatus (1) for generating an image of an object. A reconstruction unit (10) reconstructs the image based on provided measured projection values such that costs defined by a cost function are reduced, wherein the cost function depends on differences between calculated projection values, which have been determined by simulating a forward projection through the image, and the provided measured projection values, and wherein a degree of dependence of the cost function on a respective difference depends on the respective difference. This can allow for a consideration of a degree of disturbance of the measured projection values by motion and/or by an incomplete illumination of the object during the reconstruction process, which can lead to a reconstruction of an image having an improved image quality.

Abstract: A method for operating a cardiac CT imaging system (200) in coronary CT with prospective electrocardiography-triggering of the imaging system (200) is proposed. The method comprises the steps of determining a plurality of R-peak times (ti) from a dataset of electrocardiography data, determining a variability of a heart rate by statistically analyzing the determined R-peak times and automatically adjusting an acquisition time period (?Tac) of the CT imaging system (200) for acquiring projection data based on the determined variability of the heart rate.