Precise and comprehensive measurements of vascular network anatomy are crucial steps for the analysis of normal and pathologic vascular networks, and is of paramount importance for the understanding of several aspects of microcirculation [1]. Wnt/planar cell polarity signaling (PCP) pathway was found to be involved in angiogenesis [2]. The aim of this study was hence to investigate the contribution of 2 Wnt/PCP pathway receptors, frizzled 4 and frizzled 6, in 3D vascular network morphogenesis. Experiments were performed on 10 to 12-week old frizzled 4 (Fzd4-/-; n=4) and frizzled 6 (Fzd6-/-; n=3) deleted mice and littermate controls (WT; n=7), in accordance with national and European institutional ethical rules. 2 hours after injection of anticoagulant and vasodilator treatement, mice were euthanalized by pentobarbital intraperitoneal injection, exsanguinated, and perfused with a contrast medium (Neoprene latex and barium sulphate) via the brachiocephalic artery trunk. After dissection and fixation, kidneys were imaged with a high-resolution micro-CT imaging system with a voxel volume of 16 μm3, followed by subsequent 3D reconstruction of the arterial vascular networks. Computational treatment includes decomposition of 3D networks into subtree data structures based on diameter-defined Strahker order (DDSO, fig. 1), calculation of overall geometric parameters, and fractal and branching pattern analyses. Statistical comparisons were performed by one-way ANOVA with post-hoc Tukey test, and considered significant when P<0.05. Statistical data are given as mean±SD. DDSO number was 5 in WT and Fzd4-/-, and only 4 in Fzd6-/-. Both total vessel length L (in mm) total vessel volume V (in mm3), and fractal dimension Df were significant lower in fzd-deleted kidneys (WT:L=0.847±0.158; V=5.95±0.77; Df=2.07±0.11) (Fzd4-/-:L=0.26±0.086; V=2.07±0.17; Df=1.71±0.04) (Fzd6-/-:L=0.175±0.061; V=1.59±0.15; Df=1.54±0.09). Scaling characteristics such as vessel diameter were lower in Fzd4-/- and Fzd6-/-, whereas bifurcation angle distribution, around 90° form each DDSO, was not different from WT. Estimation of vessel resistance for each DDSO (RDDSO) based on Hagen-Poiseuille equation, showed a significant increase in RDDSO in Fzd4-/- and Fzd6-/-. Taken together, our results evidence important differences between WT, Fzd4-/- and Fzd6-/- mice in the size and the complexity of the arterial vasculature, whereas on the other hand, the branching patterns were not found to be significantly affected. They show that the core Wnt/PCP PCP genes frizzled 4 and frizzled 6 play a pivotal role for vessel-branching morphogenesis. The proposed methodology was found suitable for quantitative comparisons of vascular networks between different subgroups.