Hemodynamics in a cerebral artery before and after the formation of an aneursym

SUMMARY: Using data obtained from 3D digital subtraction angiography acquisitions, computational fluid dynamics techniques were used first to assess hemodynamic factors in geometrically correct models of 3 paraclinoid aneurysms and then again for assessment after virtual removal of the aneurysms and reconstruction of the parent artery. Simulations revealed an area of relatively low and rotating wall shear stresses at the location at which each aneurysm had developed. This phenomenon, to our knowledge, has not been previously described. There has been extensive speculation in the literature aboutpossible hemodynamic influences in the formation of ce-rebral aneurysms.1,2 A number of possible factors, such as wall shear stresses and dynamic pressure, have been considered, but it has not yet been possible to make comparisons of the hemodynamic conditions before and after aneurysm forma-tion. Using a recently developed algorithm for approximating the shape of the artery before aneurysm formation in 3 dimen-sions (based on techniques described by Karmonik et al3), computational hemodynamic simulations that use human pa-tient geometric data have been performed for arterial flow with andwithout the aneurysmpresent. As a result, significant correlations have been found between certain functions of the wall shear stress and the location of eventual aneurysm forma-tion. Such observations could be useful in identifying possible sites prone to aneurysm development