Morphological factors affecting vortex core instability on 4D flow MRI of unruptured cerebral aneurysms

ABSTRACT

Objective

The spatiotemporal instability of intra-aneurysmal vortex flow may be associated with unruptured cerebral aneurysm rupture. We identified morphological factors that affect intra-aneurysmal vortex core patterns classified based on the instability on four-dimensional (4D) flow magnetic resonance imaging (MRI) and determined cutoff values for the factors to discriminate unstable core patterns.

Methods

We classified vortex core patterns of 40 unruptured aneurysms on 4D flow MRI into stable, stable with a flapping tip, continuously deforming wave-or-coil-like, and non-visualized. We statistically compared nine morphological parameters among aneurysm groups with individual patterns.

Results

The vortex cores were stable (n = 16) (group A), stable with a flapping tip (n = 15) (group B), wave-or-coil-like (n = 7) (group C), and non-visualized (n = 2) (group D). Since there were no statistically significant differences between groups A and B, we compared the difference between the groups A and B and the other groups. Multivariate logistic regression analyses found that size ratio (SR) was an only independently significant parameter (p < 0.05). The receiver-operating characteristic analysis between groups A and B and group C and between groups A and B and groups C and D revealed that the area under the curve value for SR was the highest (0.829 [95% CI, 0.642–1.0]; 0.867 [95% CI, 0.715–1.0], respectively) among morphological factors; the cutoff value for SR was 1.72 (specificity 0.714, sensitivity 0.756; specificity 0.806, sensitivity 0.778, respectively).

Conclusion

SR was an independent morphological factor contributing to vortex core instability based on the vortex core patterns on 4D flow MRI.

Abbreviations: CFD: computational fluid dynamics; 3D: three-dimensional; 4D: four-dimensional; MRI: magnetic resonance imaging; MRA: magnetic resonance angiography; ICA: internal carotid artery; AR: aspect ratio; SR: size ratio; CI: confidence interval; AUC: area under the curve; ROC: receiver-operating characteristic

KEYWORDS:

• Unruptured cerebral aneurysm
• vortex core
• intra-aneurysmal flow instability
• size ratio
• 4D flow MRI

Disclosure statement

No potential conflict of interest was reported by the author(s).

Ethical approval

The study was approved by the local ethics committee of Hokuriku Central Hospital of Japan Mutual Aid Association of Public School Teachers (approval no. 19006). The study was performed in accordance with the ethical standards of the institutional research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. For this type of study, formal consent is not required. This article does not contain any studies with animals performed by any of the authors.

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.