Brain Volume Loss After Stereotactic Laser Interstitial Thermal Therapy in Patients With Temporal Lobe Epilepsy

Abstract

Background and Purpose: Temporal lobe epilepsy is the most common form of focal epilepsy. MR-guided laser interstitial thermal therapy (LITT) of the amygdalohippocampal complex has become an established therapy option in case of drug resistance. Long-term anatomic network effects on the brain due to deafferentiation have not yet been evaluated. Methods: We analyzed brain volumes of 11 patients with temporal lobe epilepsy before and 1-year after hippocampal LITT with FastSurfer segmenting T1-weighted data. Additionally, we performed visual ratings and measurements. Results: A total of 11 patients with temporal lobe epilepsy (7 left-sided, 4 right-sided) were included (5 females); the mean age years (±standard deviation) at surgery was 41.5 (±18.4) years. The mean postoperative defect size was 1427 (±517) mm3. Volumetry as well as visual ratings found a progressive volume loss after left-sided surgery in the ipsilateral temporal lobe, the contralateral (right) part of the thalamus, and especially contralateral (right) fusiform cortex. These changes could not be detected for right-sided surgery. Conclusion: A (partial) ablation of the left (dominant) hippocampus appears to exert long-term effects on the right thalamus and right-sided temporal cortices. However, we could not observe this effect in the reverse direction. Volumetric studies for larger cohorts should be conducted to investigate these findings.