Publications [#268781] of G. Allan Johnson

Papers Published
  1. Wetzel, AW; Badea, CT; Pomerantz, SM; Mistry, N; Nave, D; Johnson, GA, Measurement and modeling of 4D live mouse heart volumes from CT time series, Smart Structures and Materials 2005: Active Materials: Behavior and Mechanics, vol. 6491 (May, 2007), SPIE [doi] .

    In vivo quantitative studies of cardiac function in mouse models provide information about cardiac pathophysiology in more detail than can be obtained in humans. Quantitative measurements of left ventricular (LV) volume at multiple contractile phases are particularly important. However, the mouse heart's small size and rapid motion present challenges for precise measurement in live animals. Researchers at Duke University's Center for In Vivo Microscopy (CIVM) have developed noninvasive time-gated microcomputed tomography (micro-CT) techniques providing the temporal and spatial resolutions required for in vivo characterization of cardiac structure and function. This paper describes analysis of the resulting reconstructions to produce volume measurements and corresponding models of heart motion. We believe these are the most precise noninvasive estimates of in vivo LV volume currently available. Our technique uses binary mixture models to directly recover volume estimates from reconstructed datasets. Unlike methods using segmentation followed by voxel counting, this approach provides statistical error estimates and maintains good precision at high noise levels. This is essential for long term multiple session experiments that must simultaneously minimize contrast agent and x-ray doses. The analysis tools are built into the Pittsburgh Supercomputing Center's Volume Browser (PSC-VB) that provides networked multi-site data sharing and collaboration including analysis and visualization functions. © 2007 SPIE-IS&T.