Quantification of the ionising radiation effect over angiogenesis in the chick embryo and its chorioallantoic membrane by computerised analysis of angiographic images

Purpose: We evaluated, in vivo, the effect of ionising radiation on the ang iogenesis process in the chick embryo and its chorioallantoic membrane (CAM ) using digital subtraction angiography (DSA) in conjunction with computer- assisted image analysis. Information regarding the ionising effect on endot helial cells during radiation treatment was extracted. Material and Methods.. Two series of fertilized eggs were irradiated with a single ionising radiation dose of 10 Gy on days 9 and 13 of embryonic deve lopment. Angiography was carried out 24 h after irradiation. The angiograph ic images were digitized and subsequently processed. A set of specific morp hological parameters was defined to allow an analytical characterization of the vascularity status. Vessels were classified into three categories acco rding to their diameters (greater than or equal to 200 mum, 100-200 mum and 50-100 mum). The data were normalized and statistically evaluated. Results: On day 10, total vascular area and total vascular length presented a 15.6 +/- 1.2% and 18.4 +/- 2.4% reduction, respectively, while vascular diameters increased 3.3 +/- 0.5%. The vessel area and length of the first c ategory (greater than or equal to 200 mum) increased 9.8 +/- 1.1% and 8.1 /- 0.9%, respectively, while these morphometric parameters for each of the remaining two categories decreased 44.3 +/- 2.9%, 38.7 +/- 4.2% and 45 +/- 3.8%, 30.7 +/- 3.4%, respectively. On day 14 insignificant changes were obs erved. Conclusion. Computerised analysis of angiographic images showed that the an tiangiogenic effect of irradiation during the various phases of CAM develop ment is larger on the 10th day than that observed on day 14 and it depends on the vessel size.