Image-Based Computational Fluid Dynamics in Blood Vessel Models: Toward Developing a Prognostic Tool to Assess Cardiovascular Function Changes in Prolonged Space Flights

摘要

One of NASA’s objectives is to be able to perform a complete pre-flight evaluation of possible cardiovascular changesin astronauts scheduled for prolonged space missions. Blood flow is an important component of cardiovascular function.Lately, attention has focused on using computational fluid dynamics (CFD) to analyze flow with realistic vesselgeometries. MRI can provide detailed geometrical information and is the only clinical technique to measure all threespatial velocity components. The objective of this study was to investigate the reliability of MRI-based modelreconstruction for CFD simulations. An aortic arch model and a carotid bifurcation model were scanned in a 1.5T MRIscanner. Axial MRI acquisitions provided images for geometry reconstruction using different resolution settings. Thevessel walls were identified and the geometry was reconstructed using existing software. The geometry was thenimported into a commercial CFD package for meshing and numerical solution. MRI velocity acquisitions provided trueinlet boundary conditions for steady flow, as well as three-directional velocity data at several locations. In addition, anidealized version of each geometry was created from the model drawings. Contour and vector plots of the velocityshowed identical features between the MRI velocity data, the MRI-based CFD data, and the idealized-geometry CFDdata, with mean differences <10%. CFD results from different MRI resolution settings did not show significantdifferences (<5%). This study showed quantitatively that reliable CFD simulations can be performed in modelsreconstructed from MRI acquisitions and gives evidence that a future, subject-specific, computational evaluation of thecardiovascular system is possible.