Hemodynamics

Computational Fluid Dynamics

The management of Intracranial aneurysms is challenging. Clinicians are routinely faced with the dilemma whether or not to treat the patient.

Using a growing database of patient-specific aneurysms (currently over 400 cases, we have built 3 statistical aneurysm rupture status stratification models based on morphology, hemodynamics and the combination of the two categories. 

These rupture status prediction models are validated and demonstrated the prediction value for unruptured aneurysms.


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Flow simulation results for ruptured and un-ruptured aneurysms.


Our device modeling methods enable us to investigate the flow dynamics modifications of different treatment strategies.

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Fig 1. Flow simulation results in different treatment strategies (1-4 coils, and coil + FD)


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Fig 2. Flow comparison between uniform (C1) and dense compaction (C2) compared with unstented (U) 

Particle Image Velocimetry

Particle image velocimetry (PIV) is an optical method of flow visualizationand instantaneous velocity measurements. The fluid is seeded with very small fluorescent tracer particles. The fluid containing the particles is illuminated with a pulsing laser and a camera records the particle positions. The frames are inserted in a software which calculates the  velocity vectorial field of the flow being studied. The lab has a very powerful stereo PIV systems which is used to calculate flow in various vascular pathologies such as aneurysms and stenoses. In addition we perform endovascular device evaluation  to estimate the flow changes due to device deployment.


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Fig 1. PIV setup


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Fig 2. PIV vs. CFD comparison (both A View and commercial solver)

Research Focus

Hui Meng Ph.D., and Dr Jianping Xiang Ph.D.  head the Center's research in blood flow which addresses the fundamental problem of how aneurysms form and how the neurovascular system responds to hemodynamic changes. Dr. Meng's group is currently looking at the effect of altered hemodynamics on endothelial cells-the cells that make up the inner wall of blood vessels. 

One potential translational outcome of their efforts could be the development of diagnostic tools for differentiating between aneurysms that should be treated and those that can be left alone. It could also lead to the creation of a research-appropriate animal model of an aneurysm. None now exists and such a breakthrough would be a tremendous benefit for stroke research.

 

Dr. Meng received an R01 grant from the National Institute of Neurological Disorders and Stroke to further her group's study of hemodynamic induction of pathologic remodeling in blood vessels leading to intracranial aneurysms. Co-investigators on this multidisciplinary project include John Kolega, Ph.D., Associate Professor in the Department of Pathology and Anatomical Sciences, and Adnan Siddiqui, M.D., Assistant Professor of Neurosurgery.