The classification of intracranial aneurysm neck: a single center research experience

Clinical characteristics and treatment strategies for pituitary adenoma associated with intracranial aneurysm

BACKGROUND

This study aimed to investigate clinical features and treatment strategies for intracranial aneurysm (IA) associated with pituitary adenoma (PA).

METHODS

We enrolled patients with lesions in the sellar region and age-matched general population who were confirmed with IA from two hospitals. Four types of treatment strategies were performed, which included Type I (both IA and PA were treated with surgery), Type II (IA was treated with surgery and PA was performed by non-surgical treatment), Type III (PA was performed with surgery and observation was available for IA) and Type IV (both IA and PA were performed with non-surgical treatment).

RESULTS

The incidence of IA was 2.2% in the general population, 6.1% in patients with PA, 4.3% in patients with Rathke cleft cyst, 2.8% in patients with meningioma and none were found with IA in patients with craniopharyngioma. Age over 50 years (OR, 2.69; 95% CI, 1.20-6.04; P = 0.016), female (OR, 3.83, P = 0.003), and invasive tumor (OR, 3.26, P = 0.003) were associated with a higher incidence of IA in patients with PA. During the mean follow-up of 49.2 months, no patients experienced stroke, and recurrence of aneurysms and aneurysms treated with observation were stable. Of four patients with recurrence of PA, three patients were treated for type I and one patient for type III.

CONCLUSIONS

Preoperative evaluation for aneurysm screening is necessary due to the high incidence of IA in PA patients. Our current treatment strategies may provide a benefit for these patients.

Definition and extraction of 2D shape indices of intracranial aneurysm necks for rupture risk assessment

Purpose

Intracranial aneurysms are local dilations of brain vessels. Their rupture, as well as their treatment, is associated with high risk of morbidity and mortality. In this work, we propose shape indices for aneurysm ostia for the rupture risk assessment of intracranial aneurysms.

Methods

We analyzed 84 middle cerebral artery bifurcation aneurysms (27 ruptured and 57 unruptured) and their ostia, with respect to their size and shape. We extracted 3D models of the aneurysms and vascular trees. A semi-automatic approach was used to separate the aneurysm from its parent vessel and to reconstruct the ostium. We used known indices to quantitatively describe the aneurysms. For the ostium, we present new shape indices: the 2D Undulation Index (UI\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$_\mathrm{2D}$$\end{document}2D), the 2D Ellipticity Index (EI\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$_\mathrm{2D}$$\end{document}2D) and the 2D Noncircularity Index (NCI\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$_\mathrm{2D}$$\end{document}2D). Results were analyzed using the Student t test, the Mann–Whitney U test and a correlation analysis between indices of the aneurysms and their ostia.

Results

Of the indices, none was significantly associated with rupture status. Most aneurysms have an NCI\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$_\mathrm{2D}$$\end{document}2D below 0.2. Of the aneurysms that have an NCI\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$_\mathrm{2D}$$\end{document}2D above 0.5, only one is ruptured, which indicates that ruptured aneurysms often have a circular-shaped ostium. Furthermore, the ostia of ruptured aneurysms tend to have a smaller area, which is also correlated with the aneurysm’s size. While also other variables were significantly correlated, strong linear correlations can only be seen between the area of the ostium with the aneurysm’s volume and surface.

Conclusion

The proposed shape indices open up new possibilities to quantitatively describe and compare ostia, which can be beneficial for rupture risk assessment and subsequent treatment decision. Additionally, this work shows that the ostium area and the size of the aneurysm are correlated. Further longitudinal studies are necessary to analyze whether stable and unstable aneurysms can be distinguished by their ostia.