Hemodynamic Analysis of Intracranial Aneurysms with Daughter Blebs

Background and Purpose: Intracranial aneurysms with daughter blebs appear to have a higher risk of rupture. Whether hemodynamic factors are involved in this phenomenon is not clear. Methods: 54 patient-specific aneurysms harboring 69 daughter blebs were divided into ruptured and unruptured groups based on their clinical history. Realistic models were retrospectively constructed and analyzed by a computational fluid dynamic method. Results: There were no differences in the aspect ratio and morphology type of the aneurysms, the size of blebs or other common risk factors between the two groups. The wall shear stress (WSS) was significantly lower while the oscillatory shear index (OSI) was higher in the daughter blebs than in the primary aneurysms. Bleb-bearing aneurysms with a rupture history displayed significantly lower WSS in the daughter bleb. Of the daughter blebs, 73.9% were localized to the impingement region of the inflow jet. Conclusion: These observations indicate that low WSS and high OSI in the daughter blebs might be involved in increasing the risk of rupture. The localized striking force caused by inflow jets may contribute to the development of daughter blebs. However, a precise role of hemodynamics in predicting the future rupture of daughter blebs needs further study. Copyright (C) 2011 S. Karger AG, Basel