Aneurysm Wall Contrast Enhancement After Coiling: A Retrospective Cross- Sectional Study Comparing Ruptured and Unruptured Aneurysms

Purpose This study aimed to compare aneurysm wall enhancement post-coil embolization between patients with and without subarachnoid hemorrhage (SAH). We hypothesized that ruptured aneurysms in SAH patients exhibit different enhancement patterns compared to incidentally found unruptured aneurysms. Potential confounding factors for wall enhancement, such as coil packing density and aneurysm size, were also assessed. Methods This retrospective cross-sectional single-center study included patients who underwent coil embolization for intracranial aneurysms. Subsequently, these patients were monitored with digital subtraction angiography and magnetic resonance imaging, which included a "black blood" contrast-enhanced sequence. Data were analyzed using ROI signal intensities (SI) and visual evaluation. Quantitative and visual assessments of aneurysm wall enhancement were compared between patients with and without SAH using the two-sided Student's t-test. In addition, linear regression was performed to explore the effects of coil density and aneurysm size on wall enhancement. Results Among the 31 patients studied, those with unruptured aneurysm without SAH showed higher wall signal intensities after embolization compared to SAH patients with ruptured and coil-embolized aneurysms (Visual assessment: p = 0.02; ROI measurements: SAH: 813 SI vs. no SAH: 1151 SI, p < 0.01). No significant correlation was found between coil packing density and wall enhancement, nor was there a significant impact of aneurysm size on the enhancement in visual assessment. Conclusion Aneurysm wall enhancement after coil embolization differs significantly between patients with and without SAH, suggesting that aneurysm rupture changes the characteristics of the aneurysm wall. Coil density and aneurysm size appear to have less influence on wall enhancement.