Thalamic asymmetry on interictal SPECT in patients with frontal lobe epilepsy

Background Interictal brain single photon emission computed tomography (SPE CT) is useful for the detection of seizure focus. Recent reports indicate a hypoperfusion in the ipsilateral thalamus as a seizure focus on interictal SPECT in temporal lobe epilepsy. In frontal lobe epilepsy (FLE), however, the alteration of perfusion in the thalamus has not been well documented. T his study aimed to assess whether perfusion analysis on the thalamus may ad d useful information for the detection of epileptic foci in patients with F LE. Methods Interictal brain SPECT was performed in 11 patients with FLE. The a symmetry index for the thalamus and frontal area in the SPECT image was cal culated in order to compare the laterality of the seizure foci. Results Thalamic asymmetry was seen in seven patients (64%), while cortial asymmetry was seen in six patients (55%). The concordance with the laterali zation of the seizure foci was 6/7 (86%) in the thalamus, and 4/6 (67%) in the frontal area. Four patients showed only thalamic asymmetry. Concordance with the lateralization of the seizure focus was found in all of them. Conclusion These preliminary results suggest that hypoperfusion in the thal amus may have a complementary role to lateralize the epileptic foci in pati ents with FLE. ((C) 2001 Lippincott Williams & Wilkins).