1173. Perilesional and Extralesional Iron Deposition on Quantitative Susceptibility Mapping: In Vivo Biomarkers for Cerebral Cavernous Malformations Related Epilepsy

Authors: Li Ma; Chunxue Wu, MD; Shuo Zhang, MD; Zongze Li, MD; Lizhi Xie, MD; Yuanli Zhao, MD; Shuo Wang, MD; Jizong Zhao, MD (Beijing, China)

Introduction: Patients with cerebral cavernous malformation (CCM) -related epilepsy (CRE) could not always achieve seizure freedom after surgical resection of the lesion, suggesting an inadequate evaluation of the epileptogenic zone. Hemosiderin deposition surrounding the CCM has been proposed to be involved in the pathophysiology of CRE. In this study, we aimed to analyze the iron deposition using quantitative susceptibility mapping (QSM) MRI in CCM patients with CRE. Methods: Twenty-three patients harboring supratentorial CCM without symptomatic hemorrhage and intervention were identified in 38 patients with CCMs undergoing QSM between September 2017 and July 2018 in our institution. Three-dimensional volumetric susceptibility measurements of CCM lesion, perilesional T2 hypointensity rim and extralesional brain with increased susceptibility (>0.10 ppm, parts per million) were performed on the susceptibility map co-registered with structural images. The mean susceptibility and volume of different segments were further compared between patients with or without CRE. Results: CRE was observed in thirteen patients (56.5%, 13/23). The CCM lesions with epilepsy exhibited higher mean susceptibility in perilesional T2 hypointensity rim (0.67±0.13 ppm) than those without (0.47±0.09 ppm, P =0.02). An extralesional brain area surrounding CCM lesions exhibited increased mean susceptibility (0.22±0.15 ppm), compared with remote cortex (0.05±0.06 ppm, P <0.001). The volume of the area between T2 hypointensity rim and extralesional brain with increased susceptibility was significantly larger in patients with CCM related-epilepsy (2.52±0.96 cm 3 versus 0.40±0.35 cm 3 , P =0.01). And there was a trend toward higher susceptibility within this abnormal extralesional brain area in patients with epilepsy (0.32±0.19 ppm versus 0.16±0.09 ppm, P =0.12). Conclusion: Quantitative susceptibility mapping revealed increased perilesional and extralesional iron deposition in CCMs lesions with epilepsy. These novel biomarkers might improve the in vivo and longitudinal evaluation of CCM lesions with epilepsy.