Inter-patient variations in flow boundary conditions at middle cerebral artery from 7T PC-MRI and influence on Computational Fluid Dynamics of intracranial aneurysms

Hamidreza Rajabzadeh-Oghaz; Pim van Ooij; Sricharan S Veeturi; Vincent M Tutino; Jaco Jm Zwanenburg; Hui Meng

doi:10.1016/j.compbiomed.2020.103759

Inter-patient variations in flow boundary conditions at middle cerebral artery from 7T PC-MRI and influence on Computational Fluid Dynamics of intracranial aneurysms

Comput Biol Med. 2020 May:120:103759. doi: 10.1016/j.compbiomed.2020.103759. Epub 2020 Apr 15.

Authors

Hamidreza Rajabzadeh-Oghaz¹, Pim van Ooij², Sricharan S Veeturi³, Vincent M Tutino⁴, Jaco Jm Zwanenburg⁵, Hui Meng⁶

Affiliations

¹ Department of Mechanical and Aerospace Engineering, University at Buffalo, The State University of New York, Buffalo, NY, USA; Canon Stroke and Vascular Research Center, University at Buffalo, The State University of New York, Buffalo, NY, USA; Department of Neurosurgery, University at Buffalo, The State University of New York, Buffalo, NY, USA.
² Department of Radiology& Nuclear Medicine, Amsterdam University Medical Centers, Location Academic Medical Center, Amsterdam, the Netherlands.
³ Department of Mechanical and Aerospace Engineering, University at Buffalo, The State University of New York, Buffalo, NY, USA; Canon Stroke and Vascular Research Center, University at Buffalo, The State University of New York, Buffalo, NY, USA.
⁴ Department of Mechanical and Aerospace Engineering, University at Buffalo, The State University of New York, Buffalo, NY, USA; Canon Stroke and Vascular Research Center, University at Buffalo, The State University of New York, Buffalo, NY, USA; Department of Neurosurgery, University at Buffalo, The State University of New York, Buffalo, NY, USA; Department of Pathology and Anatomical Sciences, University at Buffalo, The State University of New York, Buffalo, NY, USA; Department of Biomedical Engineering, University at Buffalo, The State University of New York, Buffalo, NY, USA.
⁵ Department of Radiology, University Medical Center Utrecht, Utrecht, the Netherlands.
⁶ Department of Mechanical and Aerospace Engineering, University at Buffalo, The State University of New York, Buffalo, NY, USA; Canon Stroke and Vascular Research Center, University at Buffalo, The State University of New York, Buffalo, NY, USA. Electronic address: huimeng@buffalo.edu.

PMID: 32421656
DOI: 10.1016/j.compbiomed.2020.103759

Abstract

Background: Computational fluid dynamics(CFD) of intracranial aneurysms requires flow boundary conditions(BCs) as inputs. Patient-specific BCs are usually unavailable and substituted by literature-derived generic BCs. Therefore, we investigated inter-patient BC variations and their influence on middle cerebral artery aneurysmal hemodynamics.

Method: We retrospectively collected CT angiography and 7-T Phase-Contrast(PC)-MRI data from eight middle-cerebral-artery bifurcation aneurysms to reconstruct the geometry and measure the arterial flowrates, respectively. The coefficient of variation(CoV) was calculated for the inlet flowrate and the pulsatility index(PI). The outflow split estimated by Murray's law was compared with PC-MRI measurements. For each aneurysm, we performed seven simulations: "baseline" using PC-MRI-derived BCs and the other six with changing BCs to explore the influence of BC variations on hemodynamics.

Results: From PC-MRI, the inlet flowrate was 1.94 ± 0.71 cm³/s(CoV = 36%) and PI was 0.37 ± 0.13(CoV = 34%). The outflow split estimated by Murray's law deviated by 15.3% compared to PC-MRI. Comparing to "baseline" models, ±36% variations in inlet flowrate caused -61% to +89% changes in time-averaged wall shear stress(WSS), -37% to +32% in normalized WSS(NWSS; by parent-artery), and -42% to +126% in oscillatory shear index(OSI). The ±34% variations in PI caused, -46% to +67% in OSI. Applying ±15% variations in outflow split led to inflow jet deflection and -41% to +52% changes in WSS, -41% to +47% in NWSS, and -44% to +144% in OSI.

Conclusion: Inflow rate and outflow split have a drastic impact on hemodynamics of intracranial aneurysms. Inlet waveform has a negligible impact on WSS and NWSS but major impact on OSI. CFD-based models need to consider such sensitivity.

Keywords: Blood flow measurement; Boundary conditions; Cerebral aneurysms; Computational fluid dynamics; Intracranial aneurysms; PC-MRI.

Publication types

Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't

MeSH terms

Blood Flow Velocity
Cerebrovascular Circulation
Computed Tomography Angiography
Computer Simulation
Contrast Media
Hemodynamics*
Humans
Hydrodynamics
Imaging, Three-Dimensional
Intracranial Aneurysm / diagnostic imaging*
Intracranial Aneurysm / pathology
Intracranial Aneurysm / physiopathology
Magnetic Resonance Angiography
Middle Cerebral Artery / diagnostic imaging*
Middle Cerebral Artery / pathology
Middle Cerebral Artery / physiopathology
Models, Cardiovascular
Multimodal Imaging
Pulsatile Flow
Retrospective Studies

Substances

Contrast Media

Grants and funding

R01 NS091075/NS/NINDS NIH HHS/United States