The vascular system of the brain has a complex structure. One of the most important of its parts is the Willis' circle. In the article, we consider the effect of type 1 diabetes mellitus duration 1 and 2 months on the angiarchitectonics of the Willis' circle of NODSCID mice. MRA data was supplemented with mathematical post-processing. On the basis of the 3D images of blood vessels of the brain, their geometrical characteristics - angles of the vessels and the area of their orthogonal cross-sections were measured. Based on the data obtained, the following conclusions can be made: for animals with a disease development period of 1 month, there are no significant differences in the architectonics of the Willis' circle. However, with the duration of the disease for 2 months, diabetes begins to affect the architectonics of major vessels of the brain.