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Cardiac gated images in single photon emission computed tomography (SPECT) are known to suffer from increased noise due to low data counts. In this work, we investigate a 4D reconstruction approach based on an adaptive spatiotemporal smoothing prior, which is used to exploit the common signal component among the different cardiac gates in a sequence. In the experiments, we evaluated this approach...
Due to the irregularity in respiratory patterns observed clinically, the acquired data in cardiac SPECT with respiratory-gating can exhibit high variability among both gate intervals and acquisition angles. Such variability can lead to differing noise characteristics among respiratory gates, which would adversely affect the accuracy of motion estimation. To address this difficulty, we develop a joint...
Respiratory-gated acquisition with amplitude binning in cardiac SPECT can reduce the extent of motion blur, but the acquired data can exhibit high variability among both gate intervals and acquisition angles. We investigate whether we can improve the reconstruction accuracy by optimizing the motion correction among respiratory gates in the presence of such variability. To account for the differing...
Gated cardiac SPECT imaging suffers from several degrading factors ranging from limited data counts to motion blur. In this work we investigate the use of different optical flow estimation methods for motion-compensated temporal processing in gated SPECT, of which the goal is to improve the accuracy of image reconstruction. In particular, we examine how much room is still left in optical flow estimation...
Cardiac gated SPECT imaging suffers from several degrading factors including limited data counts, depth-dependent blur, attenuation, scatter, and motion blur. In recent work we demonstrated that use of temporal processing could lead to the most improvement in 4D reconstruction. In this work we investigate how motion estimation models can affect the reconstruction in 4D, and in particular, we examine...
In cardiac gated SPECT, image reconstruction suffers from several degrading factors including limited data counts, depth-dependent blur, attenuation, scatter, and motion blur. In our recent work it was demonstrated that use of motion-compensated temporal processing could lead to improved accuracy in 4D reconstruction. In this work we investigate how different optical flow estimation methods can affect...
Recently we investigated the use of a Fourier harmonic model for determining the optical flow in a periodic image sequence, the goal of which was to exploit the temporal continuity and periodicity in the underlying motion field. In this work, we further develop this optical flow model by incorporating a spatially piecewise smoothness constraint (in the form of total variation) in order to better accommodate...
Recently we developed a periodic modeling approach for determining the optical flow in a periodic image sequence, which is demonstrated to be beneficial for noise reduction in motion-compensated 4D reconstruction of cardiac gated images. In this approach, a Fourier harmonic model is used to exploit the temporal continuity and periodicity of the motion field in the sequence. In this work, we further...
In this work, we aim to develop a numerical observer for cardiac motion assessment in cardiac-gated single photon emission computed tomography (SPECT) imaging. In clinical imaging, diagnostic performance of a human observer for a specific diagnostic task is the gold standard of image quality assessment. However human studies are impractical and costly therefore the use of a numerical observer, a mathematical...
We propose an algorithm for iterative, motion-compensated reconstruction of cardiac-gated SPECT. Dose limitations in SPECT lead to high level of noise in the projection data and further in the reconstructed images. Several reconstruction techniques have been reported to mitigate for the noise effects but they process each time frame individually and do not account for data temporal correlation. Advanced...
We propose a temporal modeling approach for determining image motion from a sequence of images wherein the inherent motion is periodic over time. To exploit the periodic nature of the motion, we use a Fourier harmonic representation to model the temporal evolution of the motion field for the entire sequence. We then determine the motion field simultaneously for the different image frames by estimating...
We propose a motion-compensated non-rigid summation method for noise reduction in cardiac gated SPECT. This approach generates a static SPECT image containing counts from all frames of the gated sequence while accounting for heart motion to avoid motion-blur artifact. Static cardiac images typically suffer from heart motion occurring during acquisition which introduces the so-called motion blur artifact...
For the purpose of motion-compensated processing we propose a temporal modeling approach for determining the image motion in a gated cardiac sequence, wherein the inherent image motion is periodic over time. To exploit the periodic nature of the cardiac motion, we use a Fourier harmonic representation to describe the motion field for the entire sequence. We then determine the motion field by estimating...
We propose a temporal modeling approach for determining image motion from a sequence of images within which the inherent motion is periodic. To exploit the periodic nature of the motion, we use a Fourier harmonic representation to model the motion field for the entire sequence. We then determine the motion field by estimating the parameters of this representation model. This joint estimation approach...
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