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AJNR - American Journal of Neuroradiology

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American Journal of Neuroradiology 28:622-627, April 2007
© 2007 American Society of Neuroradiology

INTERVENTIONAL

Intra-Aneurysmal Hemodynamics during the Growth of an Unruptured Aneurysm: In Vitro Study Using Longitudinal CT Angiogram Database

S. Tateshima^a, K. Tanishita^b, H. Omura^b, J.P. Villablanca^a and F. Vinuela^a

^a Division of Interventional Neuroradiology University of California, Los Angeles, Medical Center and David Geffen School of Medicine at UCLA, Los Angeles, California
^b Department of System Design Engineering, Keio University Faculty of Science and Technology, Yokohama, Japan

Please address correspondence to Satoshi Tateshima, MD, Division of Interventional Neuroradiology, Department of Radiological Sciences, UCLA Medical Center, 10833 Le Conte Ave, CHS Rm B7–146B, Los Angeles, CA 90095-1721; e-mail: stateshi{at}ucla.edu

BACKGROUND AND PURPOSE: The role of blood-flow biomechanics on the size, morphology, and growth of cerebral aneurysms is poorly known. The purpose of this study was to evaluate intra-aneurysmal hemodynamics before and after aneurysm growth.

MATERIALS AND METHODS: A flow-simulation study was performed in a middle cerebral artery (MCA) aneurysm with a bleb that grew after 1-year follow-up. Geometrically realistic in vitro models before and after aneurysm growth were constructed on the basis of CT angiograms. Blood-flow velocity, vorticity, and wall shear stress were obtained by using particle imaging velocimetry and laser Doppler velocimetry.

RESULTS: No significant quantitative differences were noted among the overall flow structures before and after aneurysm growth, with the exception of less vorticity in the bleb after aneurysm growth. A circulating flow pattern was seen within the aneurysm domes. A blood-flow separation was observed at the margins of the bleb. No impingement of inward flow into the enlarging bleb was noted. Before the aneurysm growth, the wall shear stress was high at the aneurysm neck and also at the margin of the bleb. The value of wall shear stress decreased in the deeper part of the bleb. This value decreased even more after the aneurysm growth.

CONCLUSIONS: Intra-aneurysmal hemodynamic structures before and after the growth of an MCA aneurysm were compared. Further investigation with a similar approach is mandatory to obtain a firm conclusion.