Morphology of Cerebral Saccular Aneurysms Characterized by Neck Angle Measured in Cross Sectional Analysis.

Ryu,  Chang Woo; Koh,  Jun Seok; Kim,  Eui Jong

doi:2010.5.1.13

Neurointervention > Volume 5(1); 2010 > Article

Original Article

Neurointervention 2010;5(1):13-22.
DOI: https://doi.org/10.5469/neuroint.2010.5.1.13

Morphology of Cerebral Saccular Aneurysms Characterized by Neck Angle Measured in Cross Sectional Analysis.

Chang Woo Ryu, Jun Seok Koh, Eui Jong Kim

¹Department of Radiology, Kyunghee East-West Neo Medical Center, Kyunghee University, College of Medicine, Seoul, Korea. md.cwryu@gmail.com
²Department of Neurosurgery, Kyunghee East-West Neo Medical Center, Kyunghee University, College of Medicine, Seoul, Korea.
³Department of Radiology, Kyunghee University Medical Center, Kyunghee University, College of Medicine, Seoul, Korea.

Abstract

PURPOSE
The neck angle is the novel geometric index that quantifies the aneurismal neck on cross sectional images. We characterized the morphology of aneurysms by the neck angle measured in the cross-sectional analysis of three-dimensional rotational angiography (3DRA).
MATERIALS AND METHODS
A total of 62 patients with 69 sidewall aneurysms was included in the study. Cross sectional images were acquired in the perpendicular planes of the axis of parent arteries by use of 3DRA, and the degree of parent artery involvement by the aneurysm ostium defined as neck angle. The neck angles of the aneurysms were categorized into four groups as follows: narrow (< 75degrees), moderate (75-90degrees), wide (91-115degrees) and extremely wide (> 115degrees). The cross sectional morphology of aneurysms in each group was evaluated. We obtained geometric indices of the sidewall aneurysms on 3DRA, including the width to neck ratio, aspect ratio, bottleneck ratio, depth to diameter of parent ratio (D/Dpa); and height to diameter of the parent ratio (H/Dpa). We evaluated the relationship between the neck angle and additional determined geographic indices in each case (Pearson's correlation).
RESULTS
The neck angle was linearly related with the aneurysm-to-parent vessel size ratios (D/Dpa and H/Dpa) (p < 0.05). With increasing neck angle, the parent artery became deformed and indistinguishable from aneurismal ostium.
CONCLUSION
The neck angle is a geometric index that demonstrates the morphologic relationship between aneurysm and parent artery. The cross sectional images of intracranial aneurysms can provide important information for characterization of aneurysms.

Key Words: Intracranial aneurysm; Morphology; Three-dimensional rotational angiography