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Progressive attenuation fields: fast 2D-3D image registration without precomputation.

Torsten Rohlfing·Daniel B Russakoff·Joachim Denzler·Kensaku Mori·Calvin R Maurer
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Abstract

Computation of digitally reconstructed radiograph (DRR) images is the rate-limiting step in most current intensity-based algorithms for the registration of three-dimensional (3D) images to two-dimensional (2D) projection images. This paper introduces and evaluates the progressive attenuation field (PAF), which is a new method to speed up DRR computation. A PAF is closely related to an attenuation field (AF). A major difference is that a PAF is constructed on the fly as the registration proceeds; it does not require any precomputation time, nor does it make any prior assumptions of the patient pose or limit the permissible range of patient motion. A PAF effectively acts as a cache memory for projection values once they are computed, rather than as a lookup table for precomputed projections like standard AFs. We use a cylindrical attenuation field parametrization, which is better suited for many medical applications of 2D-3D registration than the usual two-plane parametrization. The computed attenuation values are stored in a hash table for time-efficient storage and access. Using clinical gold-standard spine image data sets from five patients, we demonstrate consistent speedups of intensity-based 2D-3D image registration using PAF DRRs by a factor of 10 over conventional ray casting DRRs with no decrease of registration accuracy or robustness.

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AlgorithmsHumansImaging, Three-DimensionalRadiographic Image Interpretation, Computer-AssistedSpineTomography, X-Ray ComputedJournal ArticleResearch Support, Non-U.S. Gov't

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Torsten Rohlfing, Daniel B Russakoff, Joachim Denzler, Kensaku Mori, Calvin R Maurer. 2005. Progressive attenuation fields: fast 2D-3D image registration without precomputation.. https://doi.org/10.1118/1.1997367

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