RESUMO
Objective To apply the swirling flow mechanism to the design of arterial prostheses with small diameters and the arterial bypass surgery to resolve the acute thrombus in small diameter prostheses after implantation, and lessen the restenosis of bypassed arteries due to the formation of internal hyperplasia. Method The computational fluid dynamics (CFD) method was used to investigate the flow field and wall shear stress distribution of a new graft, an S type bypass and an axis deviated arterial bypass, which all had the swirling flow. In addition, the platelet adhesion under swirling flow and internal hyperplasia in S-type bypass were measured. Results The swirling flow can apparently enhance the wall shear stress (WSS) and suppress the platelet adhesion and internal hyperplasia. Conclusions The swirling flow can significantly improve the flow field in arterial graft and bypass to inhibit the acute thrombus in small diameter prostheses and internal hyperplasia after bypass surgery.
RESUMO
In this paper, a new, fully-automatic method for the quantification of brain atrophy based on CT volume data is put forward by taking advantage of the characteristics of cerebral CT images in combination with the prior medical knowledge. This algorithm has been verified through the calculation of 2388 cases of normal and brain atrophy subjects.