FRACTAL GEOMETRIC ANALYSIS OF THE RENAL ARTERIAL TREE IN INFANTS AND FETUSES

Fractal geometry is a useful method of quantitating the space-filling properties of complex objects and has a particular advantage in pediat ric pathology because it is independent of organ size. The fractal dim ensions of angiographic images of 44 renal aterial trees from 23 conse nt pediatric autopsies were measured by the box-counting method. The m ean fractal dimension was 1.64 and all values were greater than the to pological dimension (one), indicating that the renal arterial tree in fetuses and infants has a fractal element to its structure. There was no significant association with size of the kidneys, confirming the si ze-independent nature of the fractal dimension. There was no significa nt association with age of the subject, and the mean value was not sig nificantly different from values obtained in studies of adult kidneys, suggesting that the degree of branching, at a lobar and lobular level , does not increase after about the 21st week of gestation. The result s are compatible with a diffusion-limited aggregation model of develop ment.