Qualitative and Quantitative Wall Enhancement on Magnetic Resonance Imaging Is Associated With Symptoms of Unruptured Intracranial Aneurysms

Abstract

Background and Purpose: Aneurysmal wall enhancement (AWE) on vessel wall magnetic resonance imaging (VW-MRI) has been described as a new imaging biomarker of unstable unruptured intracranial aneurysms (UIAs). Previous studies of symptomatic UIAs are limited due to small sample sizes and lack of AWE quantification. Our study aims to investigate whether qualitative and quantitative assessment of AWE can differentiate symptomatic and asymptomatic UIAs. Methods: Consecutive patients with UIAs were prospectively recruited for vessel wall magnetic resonance imaging at 3T from October 2014 to October 2019. UIAs were categorized as symptomatic if presenting with sentinel headache or oculomotor nerve palsy directly related to the aneurysm. Evaluation of wall enhancement included enhancement pattern (0=none, 1=focal, and 2=circumferential) and quantitative wall enhancement index (WEI). Univariate and multivariate analyses were used to identify the parameters associated with symptoms. Results: Two hundred sixty-seven patients with 341 UIAs (93 symptomatic and 248 asymptomatic) were included in this study. Symptomatic UIAs more frequently showed circumferential AWE than asymptomatic UIAs (66.7% versus 17.3%, P <0.001), as well as higher WEI (median [interquartile range], 1.3 [1.0–1.9] versus 0.3 [0.1–0.9], P <0.001). In multivariate analysis, both AWE pattern and WEI were independent factors associated with symptoms (odds ratio=2.03 across AWE patterns [95% CI, 1.21–3.39], P =0.01; odds ratio=3.32 for WEI [95% CI, 1.51–7.26], P =0.003). The combination of AWE pattern and WEI had an area under the curve of 0.91 to identify symptomatic UIAs, with a sensitivity of 95.7% and a specificity of 73.4%. Conclusions: In a large cohort of UIAs with vessel wall magnetic resonance imaging, both AWE pattern and WEI were independently associated with aneurysm-related symptoms. The qualitative and quantitative features of AWE can potentially be used to identify unstable intracranial aneurysms.

Analysis of Cerebral Aneurysm Wall Tension and Enhancement Using Finite Element Analysis and High-Resolution Vessel Wall Imaging

“…Recently, high-resolution vessel wall imaging (HR-VWI) has received attention as an effective, non-invasive way to study aneurysm wall dynamics and inflammatory responses (14)(15)(16). Wall enhancement may indicate increased risk of rupture in aneurysms (17)(18)(19). However, many open questions remain about the etiology of wall enhancement and its relation to aneurysm rupture and instability.…”

Semiautomated 3D mapping of aneurysmal wall enhancement with 7T-MRI

“…Assessment of AWE has been performed subjectively by most groups, which limits reproducibility and affects accuracy. Even the “objective methods” of AWE analysis introduce subjectivity since ROIs are manually drawn to select areas of the aneurysm deemed as “enhancing” 7 , 9 . To standardize the analysis of AWE, we previously analyzed multiple enhancement metrics and determined that a PS ratio ≥ 0.60 had a sensitivity of 81% in detecting aneurysms ≥ 7 mm in diameter.…”

“…However, in this study the PS exhibited an avid uptake of Gd in T1 + Gd images, which is suboptimal when analyzing specific AWE (SAWE). Other studies have successfully used white matter structures for normalization of enhancement through pre/post Gd indices 9 , 13 , 32 . After multiple comparisons and detailed histogram analysis, normalization to the CC resulted in a more reliable parameter in determining AWE.…”

“…Meta-analysis and several reports have consistently shown that AWE is significantly correlated with higher risk of aneurysm growth and rupture 6 . The definitions of AWE vary broadly, although recently there has been a step forward in determining AWE objectively instead of subjectively 7 – 9 . One of the major limitations in the current method of assessing AWE is that images are processed and analyzed in multiplanar 2D views and in the best-case scenario, include different segments of the aneurysm.…”

Warning Signs in the Era of Unruptured Intracranial Aneurysms: Report on 2 Cases of Fatal Aneurysmal Hemorrhage

“…Those studies indicated that for some patients with headaches, the origin of the headache was recognized too late. It is commonly mentioned in the scientific neurosurgical literature that a warning sign precedes aneurysmal rupture, but none has offered any real-life recommendations or evidence [ 14 ]. In future, aneurysm-targeted specific magnetic resonance imaging sequences might assist in diagnosing sentinel headaches [ 14 , 15 , 16 , 17 , 18 ].…”