Robustness of common hemodynamic indicators with respect to numerical resolution in 38 middle cerebral artery aneurysms

• Published in: PloS one 2017-06, Vol.12 (6), p.e0177566-e0177566
• Main Authors: Evju, Øyvind, Pozo, Jose M, Frangi, Alejandro F, Mardal, Kent-Andre
• Format: Article
• Language: English
• Subjects: Algorithms; Aneurysm; Aneurysms; Bifurcations; Biology and Life Sciences; Cerebral Angiography - methods; Coefficients; Comparative analysis; Computational biology; Computational fluid dynamics; Computer applications; Computer Simulation; Convergence; Correlation; Correlation analysis; Correlation coefficient; Fluid dynamics; Hemodynamics; Humans; Hydrodynamics; Image Processing, Computer-Assisted - methods; Indicators; Intracranial Aneurysm - diagnostic imaging; Intracranial Aneurysm - physiopathology; Medicine and Health Sciences; Methods; Middle Cerebral Artery - diagnostic imaging; Middle Cerebral Artery - pathology; Middle Cerebral Artery - physiopathology; Models, Cardiovascular; Numerical methods; Outliers (statistics); Physical Sciences; Reproducibility of Results; Robustness (mathematics); Rupture; Rupture, Spontaneous; Rupturing; Shear; Shear Strength; Shear stress; Shear stresses; Spatial analysis; Studies; Veins & arteries
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0177566

Using computational fluid dynamics (CFD) to compute the hemodynamics in cerebral aneurysms has received much attention in the last decade. The usability of these methods depends on the quality of the computations, highlighted in recent discussions. The purpose of this study is to investigate the convergence of common hemodynamic indicators with respect to numerical resolution. 38 middle cerebral artery bifurcation aneurysms were studied at two different resolutions (one comparable to most studies, and one finer). Relevant hemodynamic indicators were collected from two of the most cited studies, and were compared at the two refinements. In addition, correlation to rupture was investigated. Most of the hemodynamic indicators were very well resolved at the coarser resolutions, correlating with the finest resolution with a correlation coefficient >0.95. The oscillatory shear index (OSI) had the lowest correlation coefficient of 0.83. A logarithmic Bland-Altman plot revealed noticeable variations in the proportion of the aneurysm under low shear, as well as in spatial and temporal gradients not captured by the correlation alone. Statistically, hemodynamic indicators agree well across the different resolutions studied here. However, there are clear outliers visible in several of the hemodynamic indicators, which suggests that special care should be taken when considering individual assessment.