Objective: To elucidate specific patterns in CTP that can delineate seizure from stroke. Background: CT Perfusion (CTP) has fast become the imaging modality of choice in acute stroke. It can also shed light on stroke mimics (seizures, PRES). Many peculiar CTP changes in relation to seizures have been reported in the literature. Our study sought to delineate the specificities on CTP that can aid in the above objective. Methods: We retrospectively identified patients who presented to our center as stroke alerts but received a discharge diagnosis of seizure between 2008 and 20011. We excluded patients who did not get a CTP or EEG. We compared the patient's CTP with their EEG and MRI. Results: 91% of patients who presented with seizure, had an abnormal CTP. Of these 66% had typical CTP changes suggestive of seizure i.e. ipsilateral increased perfusion, or contralateral increased Time To Peak (TTP), or unilateral increased Cerebral Blood Flow (CBF) and decreased TTP. A minority showed globally increased CBF with EEG showing status epilepticus. The Pattern of perfusion abnormality commonly encountered in seizures was cortical ribboning, sparing the basal ganglia, and not respecting vascular territories. Large vessel CT Angiography (CTA) changes were absent. Conclusions: CTP is a valuable test to help differentiate strokes and seizures. CTP abnormalities are common in patients presenting to the ED with seizures. Particular attention to the patterns of CTP changes increases the specificity of this test. CTP imaging is now routinely available and has a shorter acquisition time than studies such as MRI or EEG making it uniquely useful for seizures. In addition, CTP may aid in targeting certain areas for biopsy in suspected pathologies like tumors and may prevent unnecessary thrombolysis. Given that cerebral blood flow mechanics is a dynamic phenomenon, the timing of CT perfusion is critical. We propose that there is likely a continuum of CTP changes in seizure: increased flow ictally, decreased flow post-ictally, and normalizing subsequently.
Disclosure: Dr. Khaku has nothing to disclose. Dr. Hedna has nothing to disclose. Dr. Waters has nothing to disclose.
Original Article: http://www.neurology.org/cgi/content/short/82/10_Supplement/P3.005?rss=1
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