Artificial blood vessel frameworks from 3D printing-based super-assembly as in vitro models for early diagnosis of intracranial aneurysms

Intracranial aneurysm (IA) is a bulge from the weak area in the wall of cerebral blood vessels and can cause serious diseases, such as hemorrhagic stroke and other neurologic diseases. Experimental and computational results demonstrated that the different flow fields of blood had a great influence on the formation, growth, and rupture of IAs. Therefore, it is crucial to acquire flow field of blood for fully characterizing the hemodynamics. In this study, six transparent models of artificial blood vessels with different growth stages of IAs by 3D printing-based super-assembly technology were first fabricated. Epoxy-based resin was used to form a 3D pipeline structure, and it played an important role in restoring the appearance of IAs and comparing with the medical image. Phase contrast-magnetic resonance imaging (PC-MRI) and computational fluid dynamics (CFD) were used to assess flow fields of IA during growth. The internal flow and wall shear stress (WSS) of inner IAs showed a very low level in the cardiac cycle compared with normal blood vessels. The CFD and PC-MRI demonstrated that the internal flow of IA gradually interfered with intravascular flow because IAs formed, and this interference gradually reduced after a mid-term stage. Meanwhile, the growth and rupture points of side IAs mainly located in the efferent region of IAs may result from the blood flow becoming extremely slow in this area. This proposed 3D printing-based super-assembly technology reduced the replica size by at least 80% and provided a visual internal structure to obtain MR imaging data.