TY - JOUR
T1 - Flow residence time in intracranial aneurysms evaluated by in vitro 4D flow MRI
AU - Li, Yinghui
AU - Amili, Omid
AU - Moen, Sean
AU - Van de Moortele, Pierre François
AU - Grande, Andrew
AU - Jagadeesan, Bharathi
AU - Coletti, Filippo
N1 - Publisher Copyright:
© 2022 The Authors
PY - 2022/8
Y1 - 2022/8
N2 - The process of an intracranial aneurysm development, growth, and rupture is multifaceted and complex. In addition, clinical observations have identified the potential of thrombus formation within such aneurysms. While the underlying mechanism is not fully understood, the thrombi represent a potential risk factor for ischemic stroke. Emerging studies indicate that blood residence time (RT) is a promising hemodynamic metric associated with the aneurysm rupture and formation of intra-aneurysmal thrombi. Here, we present a methodology to experimentally evaluate both trajectory-wise and local RT based on magnetic resonance imaging (MRI) velocimetry, and apply it to in vitro flow measurements in scaled-up replicas of 9 patient-specific intracranial aneurysms. Lagrangian tracks of massless tracers are integrated from the velocity fields and averaged to return the mean RT in the aneurysm sac. This is found to be closely approximated by a simple time scale based on the sac diameter and space–time average of the aneurysmal fluid velocity. The mean RT is also correlated with the inflow time scale at the parent artery. These results also provide a basis for the estimation of RT when high-resolution hemodynamic maps are not available. With the continuous increase in accuracy and resolution enabled by progress in MRI technology, the methodology described here may in the future be applicable to in vivo data.
AB - The process of an intracranial aneurysm development, growth, and rupture is multifaceted and complex. In addition, clinical observations have identified the potential of thrombus formation within such aneurysms. While the underlying mechanism is not fully understood, the thrombi represent a potential risk factor for ischemic stroke. Emerging studies indicate that blood residence time (RT) is a promising hemodynamic metric associated with the aneurysm rupture and formation of intra-aneurysmal thrombi. Here, we present a methodology to experimentally evaluate both trajectory-wise and local RT based on magnetic resonance imaging (MRI) velocimetry, and apply it to in vitro flow measurements in scaled-up replicas of 9 patient-specific intracranial aneurysms. Lagrangian tracks of massless tracers are integrated from the velocity fields and averaged to return the mean RT in the aneurysm sac. This is found to be closely approximated by a simple time scale based on the sac diameter and space–time average of the aneurysmal fluid velocity. The mean RT is also correlated with the inflow time scale at the parent artery. These results also provide a basis for the estimation of RT when high-resolution hemodynamic maps are not available. With the continuous increase in accuracy and resolution enabled by progress in MRI technology, the methodology described here may in the future be applicable to in vivo data.
KW - Aneurysm hemodynamics
KW - Lagrangian particle tracking
KW - Magnetic resonance imaging
KW - Residence time
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U2 - 10.1016/j.jbiomech.2022.111211
DO - 10.1016/j.jbiomech.2022.111211
M3 - Article
C2 - 35780698
AN - SCOPUS:85133274164
SN - 0021-9290
VL - 141
JO - Journal of Biomechanics
JF - Journal of Biomechanics
M1 - 111211
ER -