Enhancement of the parent artery plaque and aneurysm wall is associated with microembolic events after endovascular treatment of unruptured intracranial aneurysms

<h3>BACKGROUND AND PURPOSE:</h3> Endovascular treatment of unruptured intracranial aneurysms (UIAs) carries a potential risk of infarction due to new embolic events caused by small artery occlusion. Parent artery plaque enhancement (PAPE) and aneurysm wall enhancement (AWE) on vessel wall imaging are imaging phenotypes with multiple potential pathophysiological substrates, including but not limited to atherosclerosis. While these imaging features may reflect underlying vascular vulnerability, their relationship with postprocedural microembolic events remains unclear. The aim of this study is to investigate the relationship between PAPE or AWE on vessel wall imaging (VWI) and new microembolic events on diffusion-weighted imaging (DWI) after endovascular treatment of UIAs. <h3>MATERIALS AND METHODS:</h3> A total of 159 patients with 159 UIAs who underwent endovascular treatment and had preoperative MRI (including VWI and DWI) and postoperative MRI (including DWI) were prospective enrolled in this study. The PAPE, quantitative parent artery plaque enhancement ratio (PER), AWE, aneurysm enhancement ratio (AER), and new microembolic events were evaluated. Univariate and multivariate logistic regression analyses identified parameters associated to microembolic events. <h3>RESULTS:</h3> Among 159 patients with 159 UIAs, 57 patients with non-microemboli events and 102 patients with microemboli events were included in this study. Microembolic event patients had higher rates of PAPE (68.6% vs 14.0%; <i>P</i> &lt; 0.001) and AWE (63.7% vs 38.6%; <i>P</i> =0.02), as well as greater PER (median [IQR]: 1.2 [0.5–1.6] vs 0.3 [0.2–0.4], <i>P</i> &lt; 0.001) and AER (1.0 [0.4–1.2] vs 0.6 [0.3–1.1], <i>P</i> =0.01), compared to non-microembolic event patients. In multivariate analysis, PAPE, AWE, and PER were independent factors associated with microemboli events (OR=3.87 for PAPE [95% CI, 1.33–11.24], <i>P</i>=0.01; OR=3.45 for AWE [95% CI, 1.43–8.32], <i>P</i>=0.01; and OR=5.54 for PER [95% CI, 2.09–14.64], <i>P</i>&lt; 0.01). <h3>CONCLUSIONS:</h3> Parent artery plaque enhancement and aneurysm wall enhancement are correlated with an elevated risk of microembolic events after endovascular treatment of UIAs.