Cerebral perfusion-CT patterns following seizure.

BACKGROUND: Cerebral perfusion-CT (PCT) is commonly used to image patients with suspected stroke, but PCT may also be useful in detecting abnormalities following seizure.
METHODS: We retrospectively identified patients who presented to our stroke center between 2000 and 2008 with acute, transient neurological deficits because of seizure and received PCT imaging within 72 h. We compared the group of seizure patients with abnormal post-ictal PCT to a group of seizure patients with normal post-ictal PCT. Patients were excluded from analysis if the seizure occurred secondary to an acute process known to alter cerebral perfusion.
RESULTS: Of 27 patients with acute post-ictal neurological deficits, PCT was abnormal in 10 (37%) and normal in 17 (63%). The most common post-ictal perfusion abnormality, seen in eight of 10 patients, was focal hypoperfusion, with prolonged mean transit time (MTT) and decreased cerebral blood flow and cerebral blood volume, in a cortical ribbon pattern, multi-lobar or holo-hemispheric distribution, sparing the basal ganglia. CT Angiography (CTA) showed no corresponding large vessel pathology. Two other PCT abnormalities--focal hyperperfusion and an isolated prolonged MTT--were also observed in single patients. Imaging within 2 h after seizure termination was significantly associated with finding a post-ictal PCT abnormality (P < 0.039).
CONCLUSIONS: Post-ictal cerebral PCT abnormalities are relatively common in patients early after seizure. When PCT abnormalities occur in atypical vascular distributions--and the CTA shows no corresponding large vessel occlusions--seizure should be considered as a diagnostic possibility prior to giving acute stroke therapy.