1. Case Study Neurosurgery Michael G. Chez M.D. Director Pediatric Neurology/ SNI Samuel Ciricillo M.D. Pediatric and Adult Neurosurgery/ SNI Azad Ghassemi M.D. Neuroradiology/ SNI Laser Ablation Procedure at Sutter New Surgical Approach to Refractive Epilepsy

2. Data Flows From MRI to CPU Proprietary Software Algorithms Accurate Display of Temperature & Lesion Size: Real Time Monitoring & Control = Complete Tumor Destruction & Minimal Damage to Healthy Tissue Integrated Surgical Diode Laser Laser Delivery Visualase: MR-guided Laser Ablation Compatibility 1.5T or 3T MRI Disposable Laser Probe

3. Steps for laser ablation The precise localization of targeted tissue and insertion of a probe are performed in the OR with Intraoperative EEG Laser ablation is performed in the MRI suite with Intraoperative MRI Thermal ablation laser destroys tissue using heat ranging 50-62 degrees C (see next slide)

4. What is Laser Ablation? > 100° C Vaporization of intra- and extra-cellular water. Rupture of cell membranes. 60° - 100° C Instant denaturation of proteins and cellular components. Tissue coagulation 45° - 60°C Time-dependent thermal damage. Thermal denaturation of critical enzymes; cell death. ~ 43° C Critical temperature below which thermal damage does not occur regardless of exposure time Thermal destruction of tissue by elevation to lethal temperatures LASER ABLATION

5. Interstitial Laser Ablation Tissue Parenchyma Laser Applicator Target

6. The End Result…..

7. Initial bifrontal EEG findings convert medically to focal EEG left frontal focus

8. MEG localization Axial imageSagittal image

9. Placement Of Laser Applicator - Image Confirmation Laser Applicator Target Area Axial image

10. The End Result…..

11. Laser Ablation Test Dose 3W for 24sec Laser Doses 12W for 113sec 10W for 149sec 10W for 135sec 10W for 82sec Visualase Animation Treatment Temperature MapIrreversible Damage Estimate Animation Final Images

12. Ablation Verification Axial images 45mm Post Ablation Contrast Enhanced MR Image Visualase Damage Model 45mm by 17mm

13. Ablation Verification Sagittal images Post Ablation Contrast Enhanced MR Image Pre Ablation MEG

14. The End Result….. Home in 24 hours And playing video games the next day!