Magnetic Resonance-Guided Laser Interstitial Thermal Therapy (MR-gLiTT) in Pediatric Epilepsy Surgery: State of the Art and Presentation of Giannina Gaslini Children's Hospital (Genoa, Italy) Series

Abstract

Magnetic resonance-guided laser interstitial thermal therapy (MR-gLiTT) is a novel minimally invasive treatment approach for drug-resistant focal epilepsy and brain tumors. Using thermal ablation induced by a laser diode implanted intracranially in a stereotactic manner, the technique is highly effective and safe, reducing the risk associated with more traditional open surgical approaches that could lead to increased neurological morbidity. Indications for MR-gLiTT in pediatric epilepsy surgery include hypothalamic hamartoma, tuberous sclerosis complex, cavernoma-related epilepsy, SEEG-guided seizure onset zone ablation, corpus callosotomy, periventricular nodular heterotopia, mesial temporal lobe epilepsy, and insular epilepsy. We review the available literature on the topic and present our series of patients with drug-resistant epilepsy treated by MR-gLiTT. Our experience, represented by six cases of hypothalamic hamartomas, one case of tuberous sclerosis, and one case of dysembryoplastic neuroepithelial tumor, helps to confirm that MR-gLiTT is a highly safe and effective procedure for several epilepsy conditions in children.

Keywords: MR-gLiTT; epilepsy surgery; interstitial; laser; magnetic resonance; pediatric.

Figure 1

(A–F): Patient #2 (see Table 1), male, 2 years old. Coronal (A) and sagittal (B) T2-weighted images showing the intraventricular hypothalamic hamartoma localized on the left side (thick white arrow). Coronal T1-weighted image (C) acquired after stereotactic placement of a laser cannula within the hamartoma. Real-time MR thermogram overlaid on background T1-weighted image (D) exhibiting the irreversible damage map (yellow area within the hamartoma). Note the low-limit threshold, set at 48°C (blue arrowhead), placed on the left mammillothalamic tract, and the high limit-thresholds, set at 90°C (red arrowhead) at the tip of laser catheter and within the hamartoma. Coronal post-contrast T1-weighted image (E) performed at the end of laser ablation showing central necrosis of ablated hamartoma with peripheral contrast enhancement. Coronal T2-weighted image (F) performed 48 h after laser ablation confirming necrosis of ablated hamartoma (white arrowhead). (G–L): Patient #5 (see Table 1), male, 6 years old with tuberous sclerosis. Axial FLAIR (G) and coronal T2-weighted (H) image showing two cortical tubers in the right temporal lobe (white arrow). Axial T2-weighted image (I) acquired after stereotactic placement of two laser cannulas within the cortical tubers. Real-time MR thermogram overlaid on background T1-weighted image (J) exhibiting the irreversible damage map (yellow area within the tuber). Axial post-contrast T1-weighted image (K) performed at the end of laser ablation showing central necrosis of ablated tubers with peripheral contrast enhancement. Axial diffusion weighted image (L) overlaid on the axial T2-weighted image, performed at the end of laser ablation confirming necrosis of ablated tubers with peripheral restricted diffusion (white arrowheads). (M–R): Patient #6 (see Table 1), female, 15 years old. Coronal (M) and sagittal (N) FLAIR images showing relapsing DNET localized in the left post-central gyrus (thick white arrows). Coronal T2-weighted image (O) acquired after stereotactic placement of a laser cannula within the lesion. Real-time MR thermogram overlaid on the background T1-weighted image (P) exhibiting the irreversible damage map (yellow area within the hamartoma). Coronal post-contrast T1-weighted (Q) and FLAIR image (R) performed at the end of laser ablation showing central necrosis of ablated lesion with peripheral contrast enhancement (white arrowhead).