title: SubspaceEM: A fast maximum-a-posteriori algorithm for cryo-EM single particle reconstruction.
abstract: Single particle reconstruction methods based on the maximum-likelihood principle and the expectation-maximization (E-M) algorithm are popular because of their ability to produce high resolution structures. However, these algorithms are computationally very expensive, requiring a network of computational servers. To overcome this computational bottleneck, we propose a new mathematical framework for accelerating maximum-likelihood reconstructions. The speedup is by orders of magnitude and the proposed algorithm produces similar quality reconstructions compared to the standard maximum-likelihood formulation. Our approach uses subspace approximations of the cryo-electron microscopy (cryo-EM) data and projection images, greatly reducing the number of image transformations and comparisons that are computed. Experiments using simulated and actual cryo-EM data show that speedup in overall execution time compared to traditional maximum-likelihood reconstruction reaches factors of over 300.
authors.affiliation: Department of Diagnostic Radiology, Yale School of Medicine, New Haven, CT 06510, USA. Electronic address: nicha.dvornek@yale.edu.
authors.forename: Nicha C
authors.initials: NC
authors.lastname: Dvornek
authors.affiliation: Department of Biomedical Engineering, Yale University, New Haven, CT 06520, USA; Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, CT 06510, USA.
authors.forename: Fred J
authors.initials: FJ
authors.lastname: Sigworth
authors.affiliation: Department of Diagnostic Radiology, Yale School of Medicine, New Haven, CT 06510, USA; Department of Biomedical Engineering, Yale University, New Haven, CT 06520, USA; Department of Electrical Engineering, Yale University, New Haven, CT 06520, USA.
authors.forename: Hemant D
authors.initials: HD
authors.lastname: Tagare
mesh_terms: D000465:Algorithms; D020285:Cryoelectron Microscopy / Q000379:methods*; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D016013:Likelihood Functions; D046911:Macromolecular Substances / Q000737:chemistry*; D008958:Models, Molecular; D008962:Models, Theoretical
chemical_list: D046911:Macromolecular Substances
keywords: Cryo-electron microscopy; Expectation–maximization algorithm; Fast image processing; Maximum-a-posteriori; Maximum-likelihood; Single particle reconstruction
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