@article{GaidzikPathirajaSaalfeldetal.2020,
  author    = {Gaidzik, Franziska and Pathiraja, Sahani Darschika and Saalfeld, Sylvia and Stucht, Daniel and Speck, Oliver and Thevenin, Dominique and Janiga, Gabor},
  title     = {Hemodynamic data assimilation in a subject-specific circle of Willis geometry},
  series = {Clinical Neuroradiology},
  volume    = {31},
  journal   = {Clinical Neuroradiology},
  number    = {3},
  publisher = {Springer},
  address   = {Heidelberg},
  issn      = {1869-1439},
  doi       = {10.1007/s00062-020-00959-2},
  pages     = {643 -- 651},
  year      = {2020},
  abstract  = {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.},
  language  = {en}
}
@article{RoedelOttenDonatetal.2019,
  author    = {R{\"o}del, Claudia Jasmin and Otten, Cecile and Donat, Stefan and Louren{\c{c}}o, Marta Sofia Rocha and Fischer, Dorothea and Kuropka, Benno and Paolini, Alessio and Freund, Christian and Abdelilah-Seyfried, Salim},
  title     = {Blood Flow Suppresses Vascular Anomalies in a Zebrafish Model of Cerebral Cavernous Malformations},
  series = {Circulation Research},
  volume    = {125},
  journal   = {Circulation Research},
  number    = {10},
  publisher = {Lippincott Williams \& Wilkins},
  address   = {Philadelphia},
  issn      = {0009-7330},
  doi       = {10.1161/CIRCRESAHA.119.315076},
  pages     = {E43 -- E54},
  year      = {2019},
  abstract  = {RATIONALE: Pathological biomechanical signaling induces vascular anomalies including cerebral cavernous malformations (CCM), which are caused by a clonal loss of CCM1/KRIT1 (Krev interaction trapped protein 1), CCM2/MGC4607, or CCM3/PDCD10. Why patients typically experience lesions only in lowly perfused venous capillaries of the cerebrovasculature is completely unknown. OBJECTIVE: In contrast, animal models with a complete loss of CCM proteins lack a functional heart and blood flow and exhibit vascular anomalies within major blood vessels as well. This finding raises the possibility that hemodynamics may play a role in the context of this vascular pathology. METHODS AND RESULTS: Here, we used a genetic approach to restore cardiac function and blood flow in a zebrafish model of CCM1. We find that blood flow prevents cardiovascular anomalies including a hyperplastic expansion within a large Ccm1-deficient vascular bed, the lateral dorsal aorta. CONCLUSIONS: This study identifies blood flow as an important physiological factor that is protective in the cause of this devastating vascular pathology.},
  language  = {en}
}