Abstract: Projection data are acquired by one or more gamma detectors of a medical imaging system. The counts for each projection are binned into time bins to provide respective frames. Using a computer processor, a respective weight factor is computed for each pair of input points among a plurality of input points associated with respective time bins, each input point being an M-dimensional representation of the frame corresponding to the associated time bin for one of the projections. Each weight factor is inversely proportional to a distance computed between the corresponding pair of input points according to an adaptive distance measure that is dependent on the projection data corresponding to said one projection. An N-dimensional surrogate respiratory signal (N<M) is generated based on an optimization of a nonlinear objective function using the weight factors, wherein the surrogate respiratory signal is indicative of patient respiratory activity.

Abstract: Multiple sets of projection data are provided for respective ones of a first set of volumes. An initial image is generated for a second volume larger than each volume in the first set of volumes. Based on at least the initial image and the sets of projection data, an image of the second volume is reconstructed using multiple iterations of a single iterative reconstruction process.

Abstract: In nuclear medical imaging, respiratory motion is corrected. Rather than pairwise estimation of motion from projection views, a sequence-based technique is used to jointly estimate parameters for a motion model across many projection views. In one approach, this sequence-based method is iteratively solved with a maximum likelihood objective function incorporating the motion model. A surrogate respiration signal is used to gate for the joint estimation and used to convert gated motion parameters to temporal motion parameters.

Abstract: In SPECT reconstruction, multi-modal reconstruction is combined with model-based multi-energy image formation. The scatter modeling of the model-based image formation uses resampling to facilitate convolution with the scatter kernels while maintaining resolution for the multi-energy projection. This combination of multi-modal and model-based multi-energy image formation simultaneously addresses the inaccuracy of the image formation process for complicated energy spectra and image blurring due to degradation of resolution. Varying the reconstruction by iteration may provide some of the benefits while reducing computational burden.

Abstract: Model-based scatter correction is used in SPECT with a non-parallel-hole collimator. Model-based scatter correction uses scatter kernels based on simulation to model the scatter for a given system and patient. For non-parallel-hole collimators, the measured sensitivity and measured vector maps are used in the modeling of scatter. The measured sensitivity is used to normalize the scatter kernels simulated for a parallel-hole collimator rather than attempting to simulate scatter with the complicated arrangement of holes. The measured vector maps are used to accurately project the model-based scatter sources into a data or emissions space.

Abstract: A set of first modality data is provided to an intra-reconstruction motion correction method. The set of first modality data includes a plurality of views. A set of second modality data is provided to the method. A motion estimate is generated for each of the plurality of views in the set of first modality data by registering the set of first modality data with the set of second modality data. A motion corrected model of the set of first modality data is generated by a forward projection including the motion estimate.

Abstract: Reconstruction quality is assessed in medical imaging. An amount of local non-uniformity in a distribution of a statistical measure (e.g., MCDF) is determined. The amount indicates a level of reconstruction quality. A more easily understood amount rather than a rendering of MCDF and/or the amount being a function of local artifacts aids a radiologist in recognizing reconstruction quality and determining whether different reconstruction is warranted.

Abstract: A set of set of first modality data is received including at least one view comprising a plurality of gates. The set of first modality data is received from a first imaging modality of an imaging system. A set of second modality data is received from a second imaging modality of the imaging system. A motion corrected model of the set of first modality data is generated by forward projecting the set of first modality data including a motion estimate. An update factor for each of the plurality of views is generated by comparing at least one of the plurality of gates to the motion corrected model. The motion corrected model is updated by the update factor to generate a motion corrected image.

Abstract: Multiple sets of projection data are provided for respective ones of a first set of volumes. An initial image is generated for a second volume larger than each volume in the first set of volumes. Based on at least the initial image and the sets of projection data, an image of the second volume is reconstructed using multiple iterations of a single iterative reconstruction process.

Abstract: In quantitative SPECT with multiple photopeaks, the combination for the multiple photopeaks is performed within or as part of reconstruction rather than post-reconstruction. Reconstruction is performed iteratively, so the combination for the multiple photopeaks is performed within the iteration loop of the reconstruction, such as combining back projected feedback of the different photopeaks for updating the volume.

Abstract: Projection data are acquired for a portion of the body of a patient at multiple views using one or more detectors, the projection data including multiple two dimensional (2D) projections. A 3D image is initialized. For each view among the plurality of views, the 3D image is transformed using a view transformation corresponding to said view to generate an initial transformed image corresponding to said view, and multiple iterations of an MLEM process are performed based on at least the initial transformed image and the projection data. The MLEM process is initialized with the initial transformed image. The 3D image is updated based on an output of the MLEM process.

Abstract: Single photon emission computed tomography (SPECT) is performed with multiple emission energies. For quantitative or qualitative SPECT, the image formation process for emissions at different energy ranges is modeled (44, 46, 48, 50) separately. Different scatter, different attenuation, and/or different collimator-detector response models corresponding to different energy ranges are used in the reconstruction.

Abstract: Systematic error is estimated as a function of location in quantitative functional imaging. The systematic error is estimated by perturbing the system matrix. The values of one or more variables of the system matrix are altered, and the reconstruction repeated. The differences in the resulting object or image data of the different reconstructions provide systematic error information as a function of location.

Abstract: Segmentation is provided in multi-modal reconstruction of functional information. Rather than using HU values for segmentation, the HU values are converted into linear attenuation coefficients, such as in a ?-map (Mu map). The conversion uses different functions for different ranges of the HU values. Linear attenuation coefficients are less likely subject to variation by patient, protocol, or scanner. The resulting segmentation may be more consistent across various clinical settings, providing for more accurate multi-modal reconstruction.

Abstract: First and second images obtained from first and second imaging modalities, respectively, are set as a target image and an object image, respectively. The object image is segmented into one or more anatomic segments. Each segment is associated with a respective anatomic class. At least one attribute is assigned to at least one of the anatomic segments based on the anatomic class corresponding to said at least one anatomic segment. A registration is performed with the object image and the target image, wherein the registration is constrained by the assigned attribute(s).

Abstract: A method of clinical collaboration between a clinical site and an analysis site includes receiving scan data from a scanner via a first reconstruction computer system at the clinical site, implementing a reconstruction procedure on the received scan data using a second reconstruction computer system at the analysis site and configured in accordance with a reconstruction configuration parameter, the analysis site being remote from the clinical site, and transmitting data indicative of the reconstruction configuration parameter to the first reconstruction computer system to configure the first reconstruction computer system in accordance with the reconstruction configuration parameter.

Abstract: Computer-implemented methods of reconstructing an image object for a measured object in object space from image data in data space cause a computer system to execute instructions for providing zonal information separating the object space into at least two zones, providing at least two zonal image objects, each zonal image object being associated with one of the at least two zones, performing a zonal smoothing operation on at least one of the zonal image objects, thereby generating at least one smoothed zonal image object, reconstructing the image object on the basis of the at least one smoothed zonal image object, and outputting the image object.

Abstract: The point spread function of a multi-channel collimator is modeled in photon imaging. The geometric aperture used in the point spread function is expanded to account for penetration, scattering, and/or imperfections of the collimator. The aperture is broadened using a weight that is a function of the distance of the source from the collimator. Rather than scaling the point spread function itself, the geometric aperture used in the point spread function is scaled to an effective aperture. The distance and geometric constraints may be used to determine the geometric aperture, but an additional broadening occurs as a function of the distance to account for non-ideal photon paths of travel. This additional broadening may improve the fidelity with respect to measured data relative to purely geometric or Gaussian models.

Abstract: Systematic error is estimated as a function of location in quantitative functional imaging. The systematic error is estimated by perturbing the system matrix. The values of one or more variables of the system matrix are altered, and the reconstruction repeated. The differences in the resulting object or image data of the different reconstructions provide systematic error information as a function of location.

Abstract: First and second images obtained from first and second imaging modalities, respectively, are set as a target image and an object image, respectively. The object image is segmented into one or more anatomic segments. Each segment is associated with a respective anatomic class. At least one attribute is assigned to at least one of the anatomic segments based on the anatomic class corresponding to said at least one anatomic segment. A registration is performed with the object image and the target image, wherein the registration is constrained by the assigned attribute(s).