To illustrate Various CT perfusion (CTP) findings in the ictal continuum and post ictal state matched with EEG findings Value of CTP in excluding acute ischemia in acute stroke code scenario Multimodality imaging findings in diagnosis and confirmation of post ictal state Value of CTP and MRI in determining underlying cause of seizures

Differentiating seizure from stroke can be clinically difficult. Neurological deficits such as aphasia, paresthesia, neglect, hemiparesis, and gaze palsy can be associated with Todd’s phenomenon[i]. Along the ictal-interictal continuum, CTP may depict normal perfusion, being most common, hypoperfusion or hyperperfusion[ii]. During the ictal phase, the regional hyperperfusion can be seen in epileptogenic zone. We present CTP findings of the various seizure patients presenting with a stroke code with clinical and electroencephalography (EEG) correlation.

Non-contrast CT and CT head angiogram/post-contrast CT: On non-contrast CT (NCCT), post-ictal findings are nonspecific including mild focal gyral swelling, effacement of cortical sulci, and decreased attenuation of the gyri, suggestive of edema. The contrast-enhanced CT images in CTP protocol are helpful in identifying underlying enhancing abnormality like brain tumors, vascular abnormalities, and previous infarct. CT angiogram assists further in demonstrating no large vessel occlusion and vascular territorial ischemia. CTP: CTP findings in a classical stroke depicts hypoperfusion with increased TTP or MTT, reduced CBF...

CTP changes in seizure can vary depending on the ictal-interictal continuum. Hyperperfusion can differentiate ictal stroke mimic from acute stroke and can avoid unnecessary vascular intervention and obviates the risk of thrombolysis. Rapid interpretation of perfusion abnormalities can be challenging in acute stroke code scenario and CTP provides valuable diagnostic information that influences acute patient triage and management.

[i] Bertram E. Temporal lobe epilepsy: where do the seizures really begin?. Epilepsy & Behavior. 2009;14(1):32-37. [ii] Gugger J, Llinas R, Kaplan P. The role of CT perfusion in the evaluation of seizures, the post-ictal state, and status epilepticus. Epilepsy Research. 2020; 159:106256. [iii] Kramer D, Fujii T, Ohiorhenuan I, Liu C. Interplay between Cortical Spreading Depolarization and Seizures. Stereotactic and Functional Neurosurgery. 2017;95(1):1-5. [iv] Xu M. Poststroke seizure: optimising its management. Stroke and Vascular Neurology. 2018;4(1):48-56. [v] Dohmen C, Sakowitz O, Fabricius M, Bosche...