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Dynamic visualization of the zebrafish heart: a combination of fast microscopes and 4D reconstruction techniques

M. Liebling, A. S. Forouhar, M. Gharib, S. E. Fraser, and M. E. Dickinson

Invited Talk
28th Annual Meeting of the Molecular Biology Society of Japan
Fukuoka, Japan, December 7-11, 2005.

Abstract One of the most challenging objectives in the study of zebrafish heart development is the ability to acquire, visualize, and analyze three-dimensional time-series (4D data) at high speed. Current state-of-the-art confocal microscopes allow for 2D imaging at frame-rates as fast as 120 frames per second but do not generally permit the acquisition of 4D data at a sufficient resolution. However, when the studied specimen undergoes periodic deformation or motions (which is the case for the beating embryonic zebrafish heart), it is possible to reconstruct dynamic 3D volumes from series of unsynchronized 2D sequences without giving up temporal resolution. We acquired 2D sequences at increasing depths, triggered at random time points in the heart cycle (nongated acquisition). We have developed a digital post-acquisition synchronization algorithm that temporally realigns the sequences to build 4D reconstructions. This automatic procedure registers the sequences based on the minimization of an objective criterion that measures the similarity between the data from neighboring depths. To ensure both fast execution and robust results, the reconstructions partly take place in the wavelet domain, in which images have a sparse representation. Here, we present dynamic 3D reconstructions of embryonic zebrafish hearts at various stages of their development, that is, between 28 hpf and 148 hpf. These reconstructions are suitable for further evaluation (in particular, volume-change monitoring), heart deformation modeling, or flow analysis.