Abstract Body: Introduction: Intracranial atherosclerotic disease (ICAD) is a common cause of primary and secondary stroke. Understanding plaque evolution can help in risk stratification and in selecting proper therapies.

Hypothesis: In this study, we hypothesized that vessel wall radiomics and hemodynamic features correlate with longitudinal change in plaque volume.

Methods: Patients with ICAD and history of cerebral ischemia were included. Time-of-flight MRA, high-resolution vessel wall imaging (proton density-weighted, PD, and contrast-enhanced T1-weighted, T1CE) and phase-contrast MR-based volumetric flow (NOVA) were collected at multiple time points. MRA was used to segment lumen and perform computational fluid dynamics (CFD). NOVA flow rate used as boundary conditions. Plaques were segmented on PD images from each time point. PD and T1CE scans were co-registered and radiomics features (RFs) were extracted from the first time point from both image types. Plaques were compared between consecutive time points and classified as progressing, stable, or regressing, based on volume change (those <5mm³ were excluded). ANOVA analysis was done to determine which features were different between the 3 groups of plaques.

Results: 32 plaques from 14 patients were analyzed (12 regressing, 15 stable, 5 progressing). Mean follow-up time of MRI was 11.8 months. Mean plaque size at baseline was 20.94mm3. Average growth in the progression group was 24.33mm³. Dual antiplatelet therapy was more frequent in the regression group. 57 RFs were significantly different (p<0.05) between the groups. CFD showed no significant difference in hemodynamics; however, wall shear stress (WSS) was lower and WSS divergence was higher adjacent to regressing plaques.

Conclusion: We found significant differences in RFs between progressing, stable and regressing plaques, suggesting that vessel wall imaging can be used to better understand plaque evolution.