A computer method for determining plaque size and plaque morphology

We describe a computer method for determining plaque size and morphology from photographs of hemolytic plaques. The method eliminates any inter-measurer and intra-measurer inconsistencies that may arise when manual measurements are made on plaques whose boundaries are poorly defined. For circular plaques inner and outer plaque radii are determined. In addition the computer generates a density profile for each plaque, i.e., a plot of the film density versus the radial distance from the antibody forming cell. We demonstrate the use of the method by analyzing a time study of the growth of a single plaque.