2-DIMENSIONAL AND 3-DIMENSIONAL COMPUTER GRAPHIC EVALUATION OF THE SUBACUTE SPINAL-CORD INJURY

We have evaluated three-week-old compression lesions of the rat spinal cord using two-dimensional and three-dimensional morphometry, reconst ruction, and visualization techniques. We offer a new computer assiste d method to determine the number and density of macrophages within the spinal lesion using the macrophage specific monoclonal label ED1. We also provide quantitative information on pathological cyst formation a nd cavitation. This technique does not require: (1) subjective identif ication of the cell type, (2) human interaction with the data during t he phase of quantification, and (3) can be applied to any sampling par adigm based on immunocytochemical labeling. Using novel algorithms bas ed on solutions to 'correspondence' and 'branching' problems inherent in cross-sectional histological data, we provide three-dimensional rec onstructions and visualizations of the macrophagic lesions and cysts i mbedded within it. Our three-dimensional surface reconstructions can b e interrogated to determine volumes and surface areas of structures wi thin the data set. Using these methods we have learned that macrophage numbers approach the maximum density possible for such isodiametric c ells (similar to 12 mu m diameter) in the central lesion ranging from 4000-7000 cells per mm(2) of lesion. At the time point studied, macrop hage numbers would have peaked following the initial insult, and would not be expected to decline for several months. While the density of m acrophages is highest in the region of most tissue damage, we show tha t the central regions of cavitated and cystic spinal parenchyma is not . We discuss how this density of cells may effect the secondary pathol ogical responses of the spinal cord to injury. (C) 1998 Elsevier Scien ce B.V.