Epilepsy Stands Nearby: A Pilot CT Perfusion Study on Post-Stroke Non-Convulsive Status Epilepticus

To investigate the relevance of hyperperfusion on computerised perfusion imaging (CTP) in the emergency setting in people with non-convulsive status epilepticus (NCSE) and previous stroke, to derive relevant aspects on the epileptogenic focus and the network recruited for NCSE propagation.

We enrolled consecutive adult patients with acute-onset NCSE and a previous stroke at a single institution undergoing CTP and EEG during symptoms. All patients underwent standard imaging including CT, CTP, CT angiograms and standard EEG within 30 min from hospital arrival. Age-/sex-matched NCSE without previous stroke cases and recurrent ischaemic stroke cases were included to test for accuracy of hyperperfusion rates.

Overall, 15 patients had a previous stroke and developed NCSE (mean age 78 years, 46.7% female). All patients had hyperperfusion on CTP imaging (mean onset-to-CTP 184 min). Only one case showed hyperperfusion limited to the previous stroke lesion, and one had a combination of lesional and peri-lesional hyperperfusion. All remaining cases (n = 13) had exclusive extra-lesional involvement. Five cases had multiple separated hyperperfused areas, and five had ipsilateral intra-thalamic hyperperfusion. No correlation emerged between onset-to-CTP timing and hyperperfusion (p value for CTP = 0.66, CBV = 0.28, MTT = 0.28, reverse T_max = 0.66). Hyperperfusion was present in NCSE cases only and in none of age-/sex-matched ischaemic stroke cases (n = 18).

Hyperperfusion involves cortical areas external to the previous lesion site during NCSE, supporting the relevance of networks for the spatial evolution of epileptic activity and limited relevance of the lesion site for the propagation of the epileptiform activity.