Minimally Invasive MR Imaging‐guided Stereotactic Laser Thermal Ablation in Neurosurgical Cases of Pediatric Lesional Epilepsy: A Didactic Step-by-Step Practical Approach

MR imaging‐guided thermal ablation, an alternative to conventional surgery, is a minimally invasive procedure with a decrease in the hospital length of stay and intensive care unit use. This procedure, with converging imaging, clinical, and videotelemetry data, has had early success in selected pediatric neurosurgical patients with intractable epilepsy. Our purpose was to describe the step-by-step approach used in our institution for minimally invasive MR imaging‐guided stereotactic laser thermal ablation, along with some of its benefits. Use of fast single-shot T1- and T2-weighted sequences allows a rapid outline of the catheter position, which is followed by a targeted limited higher-resolution T2-weighted sequence for detailed assessment of the lesion margins and adjacent critical structures. In our experience, diffusion-weighted images and T2-weighted images allow fast assessment of the treatment effect and correlate well with the real-time estimate of cell death and posttreatment area of encephalomalacia. We found that contrast imaging did not change the treatment plan or outcome. Therefore, we adopted a tailored fast thermal ablation treatment imaging protocol that relied on short and fast acquisitions, including DWI and single-shot T1- and T2-weighted sequences, and allowed a decrease in imaging acquisition time to approximately 45 to 60 minutes and allowed the addition of these patients to the regular MR imaging schedule without major disruptions to overall patient flow. This new approach allowed the spectrum of surgical intervention in intractable epilepsy to include MR imaging‐guided thermal ablation as a prephase I or II alternative. A detailed procedure description was provided, followed by examples of patients we treated.

Learning Objective: Understand and describe the benefits of the step-by-step approach for minimally invasive MR imaging‐guided stereotactic laser thermal ablation in selected patients with epilepsy.