Irregular pulsation on 4D-CTA and quantitative wall enhancement on VW-MRI are associated with symptoms of unruptured intracranial aneurysms

BACKGROUND: Unruptured intracranial aneurysms (IAs) that become symptomatic have been associated with instability. OBJECTIVE: To investigate the relationship between irregular pulsation on four-dimensional CT angiography (4D-CTA) and aneurysm wall enhancement (AWE) on vessel wall MRI (VW-MRI), and to evaluate their ability to identify symptomatic IAs. METHODS: This retrospective study included consecutive patients with IAs who underwent 4D-CTA and VW-MRI between March 2018 and May 2023. IAs were categorized as asymptomatic and symptomatic. The presence of irregular pulsation was identified on 4D-CTA video. Qualitative and quantitative AWE were evaluated. Univariate and multivariate analyses were used to identify the parameters associated with symptoms. RESULTS: 192 patients with 216 aneurysms (167 asymptomatic and 49 symptomatic) were included. IAs with irregular pulsation had significantly higher wall enhancement index (WEI) than IAs without irregular pulsation (median (IQR), 0.5 (0.2-1.1) vs 0.2 (0.0-0.6), P<0.001). Symptomatic IAs had significantly higher WEI than asymptomatic IAs (median (IQR), 0.7 (0.3-1.5) vs 0.2 (0.0-0.5), P<0.001), and more irregular pulsations (79.6% vs 25.1%, P<0.001). Both irregular pulsation (OR=6.86; 95% CI 2.62 to 17.96; P<0.001) and WEI (OR=2.56; 95% CI 1.14 to 5.71; P=0.022) were independently associated with symptoms. Combination of irregular pulsation and WEI achieved the highest area under the curve of 0.86 in identifying symptomatic aneurysms compared with irregular pulsation or WEI alone (P<0.001 and P=0.002, respectively). CONCLUSION: In a large cohort of patients with unruptured IAs who underwent 4D-CTA and VW-MRI, both irregular pulsation and WEI were independently associated with symptoms. Such measures could identify IAs at higher risk of growth or rupture.