EVALUATION ON BLOOD-PLATELETS BY THE IMAGE-ANALYSIS SYSTEM VIDAS-2.5

This paper introduces a program written on the image analysis system V IDAS 2.5. It enables the automatic quantification of high numbers of a dhesion areas of vital human platelets, thus allowing statistical anal ysis. These adhesion areas were observed by reflection contrast micros copy (RCM), which generates images of an intense contrast and serves a s a prerequisite for an evaluation by image analysis. However, RCM-pho tographs of the observed platelets have highly varying mean greyvalues and greyranges. These common problems for self-operating identificati on are excluded by two procedures within the program: 1. calibration o f the scanning process for an optimal use of the available greyvalues provided by the negative, camera, and the image analysis system; and 2 . relation of the threshold for discrimination of adhesion areas to th e statistic parameters of the histogram within each individual digitiz ed image. Images processed according to these prerequisites were trans ferred to the VIDAS implemented routines for identification and measur ement of areas. Thus, image analysis combined with RCM offers a tool f or basic and clinical platelet research, which is shown by an example of stimulation and inhibited stimulation of platelet activation.