Figure 2.
A GAWE−/SAWE+ fusiform left ICA terminus aneurysm shows no enhancement on T1 (Panel A) and heterogenous enhancement on T1+Gd (Panel B, arrowhead) reconstructions. Despite apparent subjective enhancement from 7T-MRI, this aneurysm is considered GAWE−, because only 13% of spokes enhance more than the CC (Panel D). Approximately ~71% of spokes (Panel D) enhance above the SAWE cutoff (CCratio ≥0.8); therefore this aneurysm is SAWE+. Areas of focal enhancement can be visualized on both the 3D reconstruction (arrow) and 7T-MRI (arrowhead) and are represented in the right tail of the histogram (Panel C). The survival plot (Panel D) shows that the area of focal enhancement comprises only ~3% of the spokes in the aneurysm. This fusiform aneurysm uptakes Gd (SAWE+) but is not highly enhancing when compared with other aneurysms (GAWE−). Subjective analysis would have classified this aneurysm as enhancing (Panel B, inlet). *GAWE = General Aneurysm Wall Enhancement, SAWE = Specific Aneurysm Wall Enhancement, CC = Corpus Callosum