## Minimax emission computed tomography using high resolution anatomical side information and B-spline models (1999)

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Venue: | IEEE Trans. Info. Theory |

Citations: | 13 - 8 self |

### BibTeX

@ARTICLE{Hero99minimaxemission,

author = {Alfred O. Hero and Robinson Piramuthu and Student Member and Jeffrey A. Fessler and Steven R. Titus},

title = {Minimax emission computed tomography using high resolution anatomical side information and B-spline models},

journal = {IEEE Trans. Info. Theory},

year = {1999}

}

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### Abstract

Abstract—In this paper a minimax methodology is presented for combining information from two imaging modalities having different intrinsic spatial resolutions. The focus application is emission computed tomography (ECT), a low-resolution modality for reconstruction of radionuclide tracer density, when supplemented by high-resolution anatomical boundary information extracted from a magnetic resonance image (MRI) of the same imaging volume. The MRI boundary within the two-dimensional (2-D) slice of interest is parameterized by a closed planar curve. The Cramèr–Rao (CR) lower bound is used to analyze estimation errors for different boundary shapes. Under a spatially inhomogeneous Gibbs field model for the tracer density a representation for the minimax MRI-enhanced tracer density estimator is obtained. It is shown that the estimator is asymptotically equivalent to a penalized maximum likelihood (PML) estimator with resolutionselective Gibbs penalty. Quantitative comparisons are presented using the iterative space alternating generalized expectation maximization (SAGE-EM) algorithm to implement the PML estimator with and without minimax weight averaging. Index Terms—Asymptotic marginalization, Cramèr–Rao (CR) bound, expectation maximization (EM) algorithm, Fisher information, multiresolution imaging, penalized maximum likelihood, planar curves, spatially variant Gibbs field model. I.