Systematic review of hemodynamic discriminators for ruptured intracranial aneurysms

Researchers have aimed to identify unruptured intracranial aneurysms at a higher risk of rupture during follow-up for a long time. Computational fluid dynamics has been used widely to identify a hemodynamic discriminator between ruptured and unruptured aneurysms. However, this method has yet to reach a consensus between groups, which may be due, in part, to the significant degrees of freedom in hemodynamic indexes and computational workflows. The present review aims to characterize the degree of association between ruptured aneurysms and hemodynamic indexes, as well as the degree of variability between groups. A PubMed search identified 588 relevant studies. Thirteen met our criteria, yielding a total of 3,692 aneurysms. The definition of hemodynamic indexes were first carefully assessed and then classified accordingly. The variability of hemodynamic indexes between groups displayed a significant indexdependent nature. Normalizing hemodynamic indexes was an effective measure of reducing variability. Hemodynamic indexes were evaluated for associability and quantifiability. Overall, in an attempt to advance the diagnostic performance of hemodynamic indexes, these results shed light on the poor ability to interpret hemodynamic states pathologically. Future studies should incorporate the pathological significance of hemodynamic states into the design of hemodynamic indexes.