A Case Study in Pharmacologic Colon Imaging Using Principal Curves in Single-Photon Emission Computed Tomography.

In this article we are concerned with functional imaging of the colon to assess the kinetics of microbicide lubricants. The overarching goal is to understand the distribution of the lubricants in the colon. Such information is crucial for understanding the potential impact of microbicides on human immunodeficiency virus transmission. The experiment was conducted by imaging a radiolabeled lubricant distributed in the subject's colon. The tracer imaging was conducted via single-photon emission computed tomography, a noninvasive, in vivo functional imaging technique. We have developed a novel principal curve algorithm to construct a three-dimensional curve through the colon images. The algorithm was tested and debugged on several difficult two-dimensional images of familiar curves where the original principal curve algorithm does not apply. The final curve fit to the colon data is compared with experimental sigmoidoscope collection. [ABSTRACT FROM AUTHOR]