Background Inflammation of the arterial wall may lead to aneurysm formation. The presence of aneurysm enhancement on high-resolution vessel wall imaging (HR-VWI) is a marker of wall inflammation and instability. We aim to determine if there is any association between increased contrast enhancement in the aneurysmal wall and its parent artery.
Methods Patients with unruptured intracranial aneurysms (UIAs) prospectively underwent 7T HR-VWI. Regions of interest were selected manually and with a semi-automated protocol based on gradient algorithms of intensity patterns. Mean signal intensities in pre- and post-contrast T1-weighted sequences were adjusted to the enhancement of the pituitary stalk and then subtracted to objectively determine: circumferential aneurysmal wall enhancement (CAWE); parent vessel enhancement (PVE); and reference vessel enhancement (RVE). PVE was assessed over regions located 3- and 5 mm from the aneurysm’s neck. RVE was assessed in arteries located in a different vascular territory.
Results Twenty-five UIAs were analyzed. There was a significant moderate correlation between CAWE and 5 mm PVE (Pearson R=0.52, P=0.008), whereas no correlation was found between CAWE and RVE (Pearson R=0.20, P=0.33). A stronger correlation was found between CAWE and 3 mm PVE (Pearson R=0.78, P<0.001). Intra-class correlation analysis demonstrated good reliability between measurements obtained using semi-automated and manual segmentation (ICC coefficient=0.790, 95% CI 0.58 to 0.90).
Conclusion Parent arteries exhibit higher contrast enhancement in regions closer to the aneurysm’s neck, especially in aneurysms≥7 mm. A localized inflammatory/vasculopathic process in the wall of the parent artery may lead to aneurysm formation and growth.
- vessel wall
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Contributors Conception and study design: EAS; Acquisition of data: JAR and HZ; Analysis and interpretation of results: EAS and JAR; Drafting of the manuscript: EAS and JAR; Critical revision of the study: TRK, SOG, GB, MS, CPD, VM, DMH; Final approval of the version to be published: EAS.
Funding This work was supported by the 2019 Brain Aneurysm Research Grant from The Bee Foundation and by a Pilot Research Grant from the Society of Vascular and Interventional Neurology (SVIN), both granted to Edgar Samaniego. This work was conducted on an MRI instrument funded by 1S10RR028821-01.
Competing interests None declared.
Patient consent for publication Not required.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available upon reasonable request. Additional unpublished data will be made available by the corresponding author upon appropriate request.