Topographical Analysis of Aneurysm Wall Enhancement With 3‐Dimensional Mapping

Abstract

Background Aneurysm wall enhancement has been identified as a potential biomarker for aneurysm instability. Enhancement has been determined by different approaches on 2‐dimensional multiplanar views. This study describes a new method to quantify enhancement through 3‐dimensional (3D) heatmaps and histograms. Methods A custom algorithm was developed using orthogonal probes extending from the aneurysm lumen into the wall to create 3D heatmaps and histograms of wall enhancement on 7T magnetic resonance imaging. Three quantitative metrics for general, specific, and focal wall enhancement were generated from the histograms. Results Thirty‐two aneurysms were analyzed and classified based on 3D heatmaps and histograms. Larger aneurysms were more enhancing (Spearman r =0.472; P =0.006) and had more heterogeneous enhancement (Spearman r =0.557; P <0.001) than smaller aneurysms. Patterns of enhancement differed between saccular, fusiform, and thrombosed aneurysms. Fusiform aneurysms were larger ( P =0.015) and had more heterogenous enhancement compared with saccular aneurysms. Fusiform aneurysms had more areas of focal enhancement ( P <0.001) and right‐skewed histograms ( P =0.003). Conclusion The 3D analysis of aneurysm wall enhancement provides topographic data of the entire aneurysm wall. New metrics developed based on this method show that large and fusiform aneurysms have heterogenous enhancement.