Browsing by Author "Li, Emmy"

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    Post-ictal hypoperfusion detected by CT Perfusion
    (2018-05-07) Li, Emmy; Federico, Paolo; Teskey, Gordon Campbell; Lee, Ting Yim; Menon, Bijoy K.
    Background: Seizures are often followed by a period of transient neurological dysfunction whereby sensory, cognitive, or motor abilities are impaired. Alterations in cerebral blood flow (CBF) during the postictal period has been proposed as a possible mechanism for this phenomenon. Recent animal studies have shown reduced local CBF at the seizure onset zone (SOZ) lasting up to one hour following seizures (Farrell, et al., 2016). Using arterial spin labeling magnetic resonance imaging (ASL MRI), we have observed postictal hypoperfusion at the SOZ in 75% of patients lasting up to one hour (Gaxiola-Valdez, 2017). The clinical implementation of ASL as a novel tool to identify the SOZ is hampered by the limited availability of MRI on short notice. Computed tomography perfusion (CTP) also measures CBF changes and may circumvent the logistical limitations of MRI. Methods: Fifteen patients with drug resistant focal epilepsy admitted for pre-surgical evaluation were prospectively recruited and underwent CTP scanning within 80 min of a habitual seizure. Patients underwent a second scan in the interictal period after they were seizure-free for at least 24 hours. The acquired scans were visually assessed for perfusion differences and quantitatively assessed to identify areas of significant postictal hypoperfusion. Results: Postictal reductions of >15 CBF units (ml/100g-1/min-1) were seen in 12/15 patients. In 10 of these patients, the location of the hypoperfusion was partially or fully concordant with the presumed SOZ, and all patients localized additional areas of seizure propagation concordant with their electroencephalography (EEG). Conclusions: Postictal hypoperfusion can be measured by CTP. Thus, CTP has the potential to be a cost-effective and readily available tool in localizing the SOZ by measuring postictal CBF changes.