Wall enhancement of intracranial unruptured aneurysm is associated
with increased rupture risk and traditional risk factors
Andrew J. Degnan
Received: 9 March 2018 /Revised: 24 April 2018 / Accepted: 3 May 2018
European Society of Radiology 2018
Objective Aneurysm wall enhancement (AWE) on MRI has been considered an imaging marker to indicate active
aneurysm inflammation, but no prospective studies have assessed the ability of AWE to predict rupture risk or
growth. We aim to study the association of AWE with traditional risk factors and the estimated rupture risk.
Methods Seventy-seven patients (mean age, 58.4 ± 10.8 years; 57% female) with 88 asymptomatic intracranial
saccular aneurysms underwent both 3-T high-resolution MRI and three-dimensional (3D) rotational digital subtraction
angiography (DSA). Geometric and morphologic parameters were measured on DSA, and the degree of AWE on
MRI was graded. One- and 5-year rupture risks of aneurysms were estimated using the UCAS and PHASES
calculator. Parameters associated with AWE were analyzed using uni- and multivariate logistic regression.
Results Non-internal carotid artery location (OR 3.4, 95% CI 1.6-7.1) and aneurysm size (OR 1.9, 95% CI 1.3-2.7)
were independently associated with AWE (p < 0.05). Aneurysms with AWE had significantly higher estimated
rupture risk (1 and 5 year, 1.9% and 5.8%) than aneurysms without AWE (0.5% and 2.1%) (p < 0.001). Stronger
and larger areas of AWE were correlated with the aneurysm size, size ratio and estimated rupture risk (R
≥ 0.30) (p
Conclusions Prospective assessment of asymptomatic intracranial aneurysms with MRI suggests that AWE is associated with
traditional risk factors and estimated short- and medium-term rupture risk.
• AWE independently associates with aneurysm location and size.
• Aneurysms with AWE have higher rupture risk than aneurysms without AWE.
• Stronger and larger areas of AWE correlated with the aneurysm size, size ratio and rupture risk.
Keywords Magnetic resonance imaging
Digital subtraction angiography
AR Aspect ratio
AWE Aneurysm wall enhancement
CI Confidence interval
CV Coefficient of variance
DSA Digital subtraction angiography
IA Intracranial aneurysm
ICA Internal carotid artery
ICC Intra-class correlation coefficient
OR Odds ratio
SPACE Fast spin echo with variable flip angle trains
Chengcheng Zhu and Xinrui Wang contributed equally to this work.
Electronic supplementary material The online version of this article
(https://doi.org/10.1007/s00330-018-5522-z) contains supplementary
material, which is available to authorized users.
* Jianping Lu
Department of Radiology and Biomedical Imaging, UCSF, San
Francisco, CA, USA
Department of Radiology, Changhai Hospital, Shanghai, China
Department of Radiology, The Children’s Hospital of Philadelphia,
Philadelphia, PA, USA