Abstracts

Surgical resection of cavernous malformation (CM) including hemosiderin rim has been well known to be associated with better seizure control in patients with CM-related epilepsy. However, the effectiveness of Gamma Knife surgery (GKS) for CM-related epilepsy remains a subject of ongoing debate, and whether incorporating the hemosiderin rim into the radiation field is necessary for seizure control has not been evaluated. To address this question, we meticulously investigated dosimetric factors from CM alone and CM with hemosiderin rim, separately, in each patient and analyzed which factors were associated with seizure control.

In this retrospective study, 33 patients of CMs who underwent GKS for CM-related epilepsy between 1998 and 2022 were included. Patients were grouped as good versus bad outcome according to seizure control at the last follow up (comparing antiseizure medication and seizure frequency). Univariate and multivariate logistic regression were performed.

The univariate analysis showed the age (P=.032), coverage rate of gross target volume (P=.048), coverage rate of CM (P=0.016), coverage rate of CM with hemosiderin rim (P=.009), coverage rate of hemosiderin rim (P=0.004), D_min of CM (P=.014), and D_min of CM with hemosiderin rim (P=.02) were statistically significant factors. Multivariate analysis of logistic regression showed the coverage rate of CM with hemosiderin rim was statistically significant factor (P< .012) for the seizure control outcome. Cut off value of coverage rate of CMs with hemosiderin rim is 82%.