TY  - JOUR
A1  - Gaidzik, Franziska
A1  - Pathiraja, Sahani Darschika
A1  - Saalfeld, Sylvia
A1  - Stucht, Daniel
A1  - Speck, Oliver
A1  - Thevenin, Dominique
A1  - Janiga, Gabor
T1  - Hemodynamic data assimilation in a subject-specific circle of Willis geometry
JF  - Clinical Neuroradiology
N2  - Purpose The anatomy of the circle of Willis (CoW), the brain's main arterial blood supply system, strongly differs between individuals, resulting in highly variable flow fields and intracranial vascularization patterns. To predict subject-specific hemodynamics with high certainty, we propose a data assimilation (DA) approach that merges fully 4D phase-contrast magnetic resonance imaging (PC-MRI) data with a numerical model in the form of computational fluid dynamics (CFD) simulations. Methods To the best of our knowledge, this study is the first to provide a transient state estimate for the three-dimensional velocity field in a subject-specific CoW geometry using DA. High-resolution velocity state estimates are obtained using the local ensemble transform Kalman filter (LETKF). Results Quantitative evaluation shows a considerable reduction (up to 90%) in the uncertainty of the velocity field state estimate after the data assimilation step. Velocity values in vessel areas that are below the resolution of the PC-MRI data (e.g., in posterior communicating arteries) are provided. Furthermore, the uncertainty of the analysis-based wall shear stress distribution is reduced by a factor of 2 for the data assimilation approach when compared to the CFD model alone. Conclusion This study demonstrates the potential of data assimilation to provide detailed information on vascular flow, and to reduce the uncertainty in such estimates by combining various sources of data in a statistically appropriate fashion.
KW  - hemodynamics
KW  - CFD
KW  - uncertainty quantification
KW  - PC-MRI
KW  - LETKF
Y1  - 2020
U6  - https://doi.org/10.1007/s00062-020-00959-2
SN  - 1869-1439
SN  - 1869-1447
VL  - 31
IS  - 3
SP  - 643
EP  - 651
PB  - Springer
CY  - Heidelberg
ER  -