Abstract: An imaging system includes an x-ray source, a detector that receives x-rays emitted from the x-ray source, a DAS configured to count photon hits in the detector that occur at photon energies above at least a low keV threshold, a medium keV threshold, and a high keV threshold, and a computer operably coupled to the DAS. The computer is programmed to vary each of the medium keV threshold and the high keV threshold over a continuous keV range during data acquisition to define low, medium, and high keV bins that are based on the low, medium, and high keV thresholds, obtain photon counts in the low, medium, and high keV bins in a plurality of keV threshold combinations, calculate a noise variance as a function of at least one of the keV thresholds, and identify a noise minimum and low, medium, and high keV thresholds that correspond thereto.

Abstract: An imaging system includes an x-ray source, a detector that receives x-rays emitted from the x-ray source, a DAS configured to count photon hits in the detector that occur at photon energies above at least a low keV threshold, a medium keV threshold, and a high keV threshold, and a computer operably coupled to the DAS. The computer is programmed to vary each of the medium keV threshold and the high keV threshold over a continuous keV range during data acquisition to define low, medium, and high keV bins that are based on the low, medium, and high keV thresholds, obtain photon counts in the low, medium, and high keV bins in a plurality of keV threshold combinations, calculate a noise variance as a function of at least one of the keV thresholds, and identify a noise minimum and low, medium, and high keV thresholds that correspond thereto.

Abstract: An apparatus includes a computed tomography (CT) scanner (10), a reconstructor (46), a polychromatic corrector (50), a material classifier (54) and an image processor (60). The scanner provides spectral CT information. The reconstructor (46) reconstructs the data from the CT scanner (10) into a volume space. The material classifier (54) determines a material composition of locations in the volume space as a function of their location in an attenuation space. Information indicative of the material composition is presented on a display (62).

Abstract: In a diagnostic imaging system (10) two-dimensional projection data is collected in a data memory (30). The data is sorted into the data sets collected during selected cardiac phases. A re-binning processor (38) re-bins the projection data into a parallel ray format. An adaptive filter (70) filters the parallel ray format data with each of a plurality of different filter channels based on a calculated photonic noise of each reading and assuming an arbitrary noise reduction factor, different for each filter channel. A convolver (78) convolves the data filtered with each of the filter channels. A noise reduction factor processor (84) determines the actual noise reduction factor occurring due to the weighted averaging of readings contributing to each voxel ? at an angle ??[0, 7?). A weighting processor (90) weights the convolved data from each of the filter channels based on the channels' noise reduction factors and the actual noise reduction factor.

Abstract: An apparatus includes a computed tomography (CT) scanner (10), a reconstructor (46), a polychromatic corrector (50), a material classifier (54) and an image processor (60). The scanner provides spectral CT information. The reconstructor (46) reconstructs the data from the CT scanner (10) into a volume space. The material classifier (54) determines a material composition of locations in the volume space as a function of their location in an attenuation space. Information indicative of the material composition is presented on a display (62).

Abstract: In a diagnostic imaging system (10) two-dimensional projection data is collected in a data memory (30). The data is sorted into the data sets collected during selected cardiac phases. A re-binning processor (38) re-bins the projection data into a parallel ray format. An adaptive filter (70) filters the parallel ray format data with each of a plurality of different filter channels based on a calculated photonic noise of each reading and assuming an arbitrary noise reduction factor, different for each filter channel. A convolver (78) convolves the data filtered with each of the filter channels. A noise reduction factor processor (84) determines the actual noise reduction factor occurring due to the weighted averaging of readings contributing to each voxel ? at an angle ??[0, 7?). A weighting processor (90) weights the convolved data from each of the filter channels based on the channels' noise reduction factors and the actual noise reduction factor.