Bayesian reconstruction and use of anatomical a priori information for emission tomography

Abstract

A Bayesian method is presented for simultaneously segmenting and reconstructing emission computed tomography (ECT) images and for incorporating high-resolution, anatomical information into those reconstructions. The anatomical information is often available from other imaging modalities such as computed tomography (CT) or magnetic resonance imaging (MRI). The Bayesian procedure models the ECT radiopharmaceutical distribution as consisting of regions, such that radiopharmaceutical activity is similar throughout each region. It estimates the number of regions, the mean activity of each region, and the region classification and mean activity of each voxel. Anatomical information is incorporated by assigning higher prior probabilities to ECT segmentations in which each ECT region stays within a single anatomical region. This approach is effective because anatomical tissue type often strongly influences radiopharmaceutical uptake. The Bayesian procedure is evaluated using physically acquired single-photon emission computed tomography (SPECT) projection data and MRI for the three-dimensional (3-D) Hoffman brain phantom. A clinically realistic count level is used. A cold lesion within the brain phantom is created during the SPECT scan but not during the MRI to demonstrate that the estimation procedure can detect ECT structure that is not present anatomically.

Partial Volume Correction Strategies in PET

“…By contrast, Zhang and colleagues [57] and Bowsher and colleagues [58] have proposed elaborate and involved methods that are able to account for exceptions to the assumed anatomy-function correlation and thus allow for the possibility that intensity regions in the emission reconstruction may not correspond to regions in the anatomic image. These methods, however, require some user interactions and the estimation of several hyperparameters.…”

The Use of Anatomical Information for Molecular Image Reconstruction Algorithms: Attenuation/Scatter Correction, Motion Compensation, and Noise Reduction

“…Another regularizer can encourage similar intensity values of molecular image for similar regions of anatomical image such as Bowsher prior [42,43,109]. Information theoretic measure can be used to design R(f ; g) in Eq.…”

“…Motion information from high-resolution anatomical information such as CT [35,36] or MR [37][38][39][40] was incorporated into reconstruction for motion-corrected PET or SPECT. Ideas of using structural couplings between molecular and anatomical images for reconstruction have been studied a couple of decades ago [41][42][43]. Recently, interesting advances for noise reduction of molecular images using anatomical information have been introduced with state-of-the-art methods for post-reconstruction filtering [44][45][46][47] or regularization in inverse problems [48][49][50][51][52][53].…”

Simultaneous technetium-99m/thallium-201 SPECT imaging with model-based compensation for cross-contaminating effects

“…We have extended the method for use with iterative reconstructions. When performing iterative reconstruction, the cross-talk estimate can be added to the forward projection in order to achieve compensation (Lange and Carson, 1984;Bowsher et al, 1996). This is similar to performing a pre-reconstruction subtraction, but it has the advantage that it preserves the Poisson statistics of the projection data.…”