Associations between morphology and hemodynamics of intracranial aneurysms based on 4D flow and black-blood magnetic resonance imaging

Background: Previous studies have hypothesized that intracranial aneurysm (IA) morphology interacts with hemodynamic conditions. Magnetic resonance imaging (MRI) provides a single image modality solution for both morphological and hemodynamic measurements for IA. This study aimed to explore the interaction between the morphology and hemodynamics of IA using black-blood MRI (BB-MRI) and 4D flow MRI. Methods: A total of 97 patients with unruptured IA were recruited for this study. The IA size, size ratio (SR), and minimum wall thickness (mWT) were measured using BB-MRI. Velocity, blood flow, pulsatility index (PI), and wall shear stress (WSS) were measured with 4D flow MRI. The relationship between hemodynamic parameters and morphological indices was investigated by linear regression analysis and unpaired two-sample t-test. To determine the independent interaction, multiple linear regression analysis was further performed. Results: The findings showed that mWT was negatively correlated with IA size (r=-0.665, P<0.001). Maximum blood flow in IA (Flow(IA)) was positively correlated with IA size (r=0.458, P<0.001). The average WSS (WSSavg) was negatively correlated with IA size (r=-0.650, P<0.001). The relationships remained the same after the multivariate analysis was adjusted for hemodynamic, morphologic, and demographic confounding factors. The WSSavg was positively correlated with mWT (r=0.528, P<0.001). In the unpaired two-sample t-test, mWT, WSSavg, and Flow(IA) were statistically significantly associated with the size and SR of IAs. Conclusions: There is potential for BB-MRI and 4D flow MRI to provide morphological and hemodynamic information regarding IA. Blood flow, WSS, and mWT may serve as non-invasive biomarkers for IA assessments, and may contribute to a more comprehensive understanding of the mechanism of IA.

Automated summary

This study investigated the interaction between morphology and hemodynamics of intracranial aneurysms using BB-MRI and 4D flow MRI. The findings revealed significant correlations between mWT, WSSavg, and Flow(IA) with the size and SR of IAs, which remained consistent after adjusting for confounding factors through multivariate analysis. There is potential for these imaging modalities to serve as non-invasive biomarkers for IA assessments and contribute to a more comprehensive understanding of IA mechanisms.