Regional Cerebral Hyperperfusion with Ictal Dystonic Posturing: Ictal–Interictal SPECT Subtraction

Summary:  Purpose: Ictal–interictal single-photon emission computed tomography (SPECT) subtraction was performed to find brain structures related to ictal dystonic posturing (DP) in patients with temporal lobe epilepsy (TLE).

Methods: Thirty-two patients with mesial TLE who had ictal and interictal SPECTs were included. They were divided into two groups; DP group with ictal dystonia during ictal SPECT (n = 15) and Non-DP group without ictal DP (n = 17). Ictal–interictal SPECT subtraction was performed, and then subtracted SPECT was coregistered with brain spoiled gradient recalled (SPGR) magnetic resonance imaging (MRI). The ictal hyperperfusion on subtracted SPECT was analyzed in basal ganglia, frontal cortex, thalamus, temporal lobe, and insular cortex.

Results: The incidences of ictal hyperperfusion on brain regions in DP versus Non-DP groups were 80.0% (12 of 15 patients) versus none (0 of 17), p = 0.001, χ², in caudate nucleus; 93.3% (14 of 15) versus 47.0% (eight of 17), p = 0.005, in putamen; and 80.0% (12 of 15) versus 41.2% (seven of 17), p = 0.026, in thalamus. No significant difference of ictal hyperperfusion was found in globus pallidus, temporal lobes, insular and frontal cortices between DP and Non-DP groups. DP patients showed an earlier age at seizure onset [8.6 years (DP) vs. 15.7 years (Non-DP) (p = 0.015)] and a longer duration of seizure history [19.0 years (DP) vs. 11.9 years (Non-DP) (p = 0.015)].

Conclusions: Caudate nucleus, putamen, and thalamus were significantly related to the ictal DP during TLE seizures. Our study showed first an active involvement of the caudate nucleus in the generation of ictal DP.