Utilization of image analysis for the quantification of vascular responses in the chick chorioallantoic membrane

An attempt has been made to quantify the vascular response in the CAM by using the method of automatic image analysis. In order to obtain a measure for the divergence of preparations with radial capillary growth from unchanged CAM preparations the lengths of radially arranged capillaries were measured, the relative frequency computed and compared with that of radially arranged capillary pieces in normal CAM preparations. The areal difference between both histograms is used as a measure for the grade of neovascularization Investigations performed to test the reproducibility and reliability of this measuring method have given a measuring accuracy of about +/- 20%; this value is comparable with that found by the method of radial vessel counting. The mean values of samples each consisting of 10 preparations obtained by the method of vessel counting and by the automatic measurement correlate quite well (r = 0.97). Angiogenic responses of different grades were produced in the CAM by dropping calf plasma on the CAM surface in amounts between 1 and 10 microliter. Although the individual values in the single groups vary within a wide range, a dose-response-relationship could be established both by the automatic measurement and by the method of radial vessel counting. Further improvements of the measuring procedure and a shortening of the measuring time from 5-10 min to 1 min or less could make this automatic method very suitable for the quantification of vascular responses in larger experimental series.