title: Cranial nerve threshold for thermal injury induced by MRI-guided high-intensity focused ultrasound (MRgHIFU): preliminary results on an optic nerve model.
abstract: Future clinical applications of magnetic resonance imaging-guided high-intensity focused ultrasound (MRgHIFU) are moving toward the management of different intracranial pathologies. We sought to validate the production, safety, and efficacy of thermal injury to cranial nerves generated by MRgHIFU. In this study, five female domestic pigs underwent a standard bifrontal craniectomy under general anesthesia. Treatment was then given using an MRgHIFU system to induce hyperthermic ablative sonication (6 to 10 s; 50 to 2000 J.) Histological analyses were done to confirm nerve damage; temperature measured on the optic nerve was approximately 53.4°C (range: 39°C to 70°C.) Histology demonstrated a clear definition between a necrotic, transitional zone, and normal tissue. MRgHIFU induces targeted thermal injury to nervous tissue within a specific threshold of 50°C to 60°C with the tissue near the sonication center yielding the greatest effect; adjacent tissue showed minimal changes. Additional studies utilizing this technology are required to further establish accurate threshold parameters for optic nerve thermo-ablation.
authors.affiliation: Department of Neurosurgery, Chaim Sheba Medical Center, Tel Hashomer, Israel. sagi.harnof@sheba.health.gov.il
authors.forename: Sagi
authors.initials: S
authors.lastname: Harnof
authors.forename: Zion
authors.initials: Z
authors.lastname: Zibly
authors.forename: Zvi
authors.initials: Z
authors.lastname: Cohen
authors.forename: Andrew
authors.initials: A
authors.lastname: Shaw
authors.forename: Cody
authors.initials: C
authors.lastname: Schlaff
authors.forename: Neal F
authors.initials: NF
authors.lastname: Kassel
mesh_terms: D000818:Animals; D003389:Cranial Nerve Diseases / Q000473:pathology; D003391:Cranial Nerves / Q000473:pathology / Q000528:radiation effects; D005260:Female; D057086:High-Intensity Focused Ultrasound Ablation / Q000009:adverse effects* / Q000379:methods; D006651:Histocytochemistry; D008279:Magnetic Resonance Imaging / Q000009:adverse effects* / Q000379:methods; D009900:Optic Nerve / Q000473:pathology / Q000528:radiation effects*; D020221:Optic Nerve Injuries / Q000473:pathology*; D011874:Radiometry; D013552:Swine