Modal analysis of blood flows in saccular aneurysms

TL;DR

This study demonstrates that Dynamic Mode Decomposition (DMD) effectively analyzes blood flow dynamics in brain aneurysms across various data resolutions, offering a promising tool for in-vivo hemodynamic assessment despite current imaging limitations.

Contribution

The paper introduces the application of Hankel-DMD and Optimized-DMD to low-resolution blood flow data, validating their robustness for clinical hemodynamic analysis.

Findings

DMD characterizes inflow jet dynamics at low resolutions.

Flow instabilities and large-scale structures are separable by DMD.

DMD's energy spectrum quantifies flow dynamics reliably across resolutions.

Abstract

Currently, it is challenging to investigate aneurismal hemodynamics based on current in-vivo data such as Magnetic Resonance Imaging or Computed Tomography due to the limitations in both spatial and temporal resolutions. In this work, we investigate the use of modal analysis at various resolutions to examine its usefulness for analyzing blood flows in brain aneurysms. Two variants of Dynamic Mode Decomposition (DMD): (i) Hankel-DMD; and (ii) Optimized-DMD, are used to extract the time-dependent dynamics of blood flows during one cardiac cycle. First, high-resolution hemodynamic data in patient-specific aneurysms are obtained using Computational Fluid Dynamics. Second, the dynamics modes, along with their spatial amplitudes and temporal magnitudes are calculated using the DMD analysis. Third, an examination of DMD analyses using a range of spatial and temporal resolutions of hemodynamic data to validate the applicability of DMD for low-resolution data, similar to ones in clinical practices. Our results show that DMD is able to characterize the inflow jet dynamics by separating large-scale structures and flow instabilities even at low spatial and temporal resolutions. Its robustness in quantifying the flow dynamics using the energy spectrum is demonstrated across different resolutions in all aneurysms in our study population. Our work indicates that DMD can be used for analyzing blood flow patterns of brain aneurysms and is a promising tool to be explored in in-vivo.