Towards the Clinical utility of CFD for assessment of intracranial aneurysm rupture – a systematic review and novel parameter-ranking tool

Abstract

BackgroundIntracranial aneurysms (IAs) are vascular dilations on cerebral vessels that affect between 1%–5% of the general population, and can cause life-threatening intracranial hemorrhage when ruptured. Computational fluid dynamics (CFD) has emerged as a promising tool to study IAs in recent years, particularly for rupture risk assessment. However, despite dozens of studies, CFD is still far from clinical use due to large variations and frequent contradictions in hemodynamic results between studies.PurposeTo identify key gaps in the field of CFD for the study of IA rupture, and to devise a novel tool to rank parameters based on potential clinical utility.MethodsA Pubmed search identified 231 CFD studies for IAs. Forty-six studies fit our inclusion criteria, with a total of 2791 aneurysms. For included studies, study type, boundary conditions, solver resolutions, parameter definitions, geometric and hemodynamic parameters used, and results found were recorded.Data synthesisAspect ratio, aneurysm size, low wall shear stress area, average wall shear stress, and size ratio were the parameters that correlate most strongly with IA rupture.LimitationsSignificant differences in parameter definitions, solver spatial and temporal resolutions, number of cycles between studies as well as frequently missing information such as inlet flow rates were identified. A greater emphasis on prospective studies is also needed.ConclusionsOur recommendations will help increase standardization and bridge the gaps in the CFD community, and expedite the process of making CFD clinically useful in guiding the treatment of IAs.

Systematic review of hemodynamic discriminators for ruptured intracranial aneurysms

“…Zhou reported a lower mean WSS (p = 0.037) in ruptured cases and no significant difference in OSI [44], which agreed with the findings by Can and Du [43]. Liang developed a scoring system for a variety of indexes and showed that the highest score was found for aspect ratio, followed by aneurysm size, LSA, average WSS, size ratio, minimum WSS, flow complexity, and OSI, whereas a much lower score was found for maximum WSS [40]. Most importantly, geometric factors are better discriminators than hemodynamic factors.…”

“…This article excluded studies with a small number of aneurysms and location-specific aneurysms; however, it included serial studies from the same laboratory (hereinafter referred to as serial studies), which were not common in previous systematic reviews [40,43,44]. Thus, we begin with comparisons with those reviews.…”

“…Outputted pressure and velocity are further processed to extract a certain amount of characteristic phenomena of interest along with significant degrees of freedom, resulting in a wide variety of indexes reported in the literature. Liang points out the need to increase the degree of standardization [40]. Several trials with multi-institutional collaborations have aimed to improve standardization.…”

Vessel wall imaging in intracranial aneurysms

“…25 Although these observational studies have associated aneurysm size and shape with enhancement on HR-VWI, computational flow dynamics data have suggested that the increased turbulent blood flow within larger and more irregular aneurysms might induce contrast stagnation along the vessel wall and concomitant pseudo-enhancement ( figure 4). 26 on July 11, 2020 by guest. Protected by copyright.…”

Impacts of Internal Carotid Artery Revascularization on Flow in Anterior Communicating Artery Aneurysm: A Preliminary Multiscale Numerical Investigation

“…Hemodynamics characteristics have been suggested to play key roles in the initiation, development and rupture of IAs [14][15][16]. Various hemodynamic factors, including wall shear stress (WSS) and high oscillating shear index (OSI), are involved in IA development through regulating arterial wall remodeling [17][18][19].…”