2111 Dark-Blood 3D TSE Captures Enhancement Kinetics of Intracranial Aneurysms for Lesion Risk Assessment

INTRODUCTION: Intracranial aneurysms (IAs) have an incidence of approximately 2-3%, with subarachnoid hemorrhage secondary to aneurysm rupture bearing a high mortality rate. Gadolinium-enhanced MR-vessel imaging (VWI) has been identified as a promising tool for assessing the inflammation and instability of IAs, which are predictors of rupture risk. METHODS: A single-center, IRB-approved retrospective chart review included patients with unruptured IAs scanned with MR-VWI between August 2019 and September 2020. Exclusions were made for aneurysms adjacent to the cavernous sinus, aneurysms <2 mm, and studies with poor diagnostic value due to motion degradation. MR-VWI was performed using T1-weighted 3D dark-blood TSE sequences, with pre-contrast and post-contrast acquisitions at early (∼10 minutes) and delayed (∼25 minutes) time points. Signal intensity (SI) of enhancement in IAs was computed using ROIs and normalized to adjacent white matter. RESULTS: 40 IAs in 34 patients were evaluated. IAs showed a statistically significant increase in normalized SI from pre-contrast to early and delayed post-contrast scans (p<0.001). Mean normalized SI increased by 9.69% between early and delayed phases. IAs with wall enhancement (AWE) demonstrated continued enhancement into the delayed phase, distinguishing them from non-AWE lesions. CONCLUSION: High-resolution, “off-the-shelf” T1W dark-blood MR-VWI can effectively identify signal changes in IA walls, reflecting continued contrast absorption and indicating instability. The delayed phase kinetic signature suggests that examining enhancement in both early and delayed phases can improve IA diagnosis and risk stratification. Future studies should explore the correlation between enhancement patterns and histopathological findings to validate these imaging biomarkers.