| Background:Internal carotid artery (ICA) is one of the important artery of brain, it provide a large proportion of blood to nourish the bilateral cerebral hemisphere. ICA walks crooked, especially the part of skull base and has complex surrounding anatomical structures, with numerous vessels, nerves and other organization structures. It has an important significance for imaging diagnosis and clinical treatment with further researching on the hemodynamics of intracranial aneurysm and its formation, development and rupture.Objective:(1) To observe or measure the courser and morphology of C7segment of internal carotid artery (ICA-C7) with multi-slice spiral CT angiographic (MSCTA), the authors expect to provide normal anatomical basis for these disease diagnosis and interventional treatment.(2) To individually construct the two-way flow-solid coupling model (TWFSCM) of internal carotid artery aneurysm (ICA-A), and simulate its flows and explore the Hemodynamic mechanisms of aneurysm in ICA-C7in its growth and rupture.Methods:103cases without significant lesions on the head and neck vascular disease were selected from the PACS in our hospital that consisted of49males and54females average age were48.165±11.323, aged between23and71. The inner diameter in their origin, courser and morphology of ICA-C7, Posterior communicating artery(PCoA) and Anterior choroidal artery (AChA) were observed by an ADW4.6workstation. The imaging method mainly include Maximum intensity project(MIP), Volume rending(VE), and multi planar reconstruction(MPR). The display rate of these arteries at all level was also calculated.(2) A case of internal carotid-Posterior communicating artery aneurysms was selected from the PACS in our hospital, of which the images were saved as DICOM format were gained after64slice CT angiography. A solid model was generated in the mimics15.0software (trial version). Then the model should be imported into3matric7.0software to shell in order to generate the models of aneurysm wall and flow field. Then the fluid-solid coupled and flow simulation were done in Ansys+Fluent software after these models were divided into Finite Element Mesh. The hemodynamic parameters inside of the aneurysm were observed and displayed in different states. Results:(1) MSCTA3-D reconstruction can clearly display the trunk of ICA-C7, PCoA, AChA, PCA and the interrelationship of them. The frequency of MSCTA to display including ICA-C7, PCoA and AChA in general adults was100%(left),100%(right),89.3%(left),85.4%(right),87.3%(left) and89.3%(right) respectively. The inner diameters of these arteries were3.479±0.416mm (left)、3.408±0.407mm (right),1.221±0.417mm (left)、1.255±0.477mm (right),1.000±0.154mm (left) and0.961±0.172mm (right). The inner diameter of these arteries were no significant difference between left and right, but the inner diameter of ICA-C7in male was bigger than female’s.(3) the TWFSCM of ICA-A were built, it has the same morphology and anatomy as the CT3D imaging.(4)In whole cardiac cycle (0.74s), the blood flow of aneurysm body is swirl type and its velocity is slower than the aneurysm neck; the deformation, wall shear stress, pressure and von mises stress of aneurysm wall were the maximum at the neck, the minimum at the top, but there was a secondary high pressure zone at the top.Conclusion:(1)3-D imaging post-processing technology in MSCTA is beneficial to display the ICA and its branches, it can provide technical premise for more accurate imaging anatomy.(2) The inner diameter of ICA-C7is related to sex, male’s is bigger than female’s. Posterior communicating artery and anterior choroidal artery can be shown with a high rate.(3) On the basis of MSCT angiography scan data, to construct the TWFSCM is a simple and practical method. The blood flow simulation of aneurysm is close to the human physiological conditions, the results will provide new theoretical basis for the study on the occurrence and development of aneurysm. |
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