title: Sonoablation and application of MRI guided focused ultrasound in a preclinical model.
abstract: Stereotaxic sonoablative surgery by MRI guided high intensity focused ultrasound (FUS) holds great potential in disorders of the central nervous system (CNS). We previously described the ExAblate 2000 system (InSightec, Tirat Carmel, Israel), currently in use for various pathologies including uterine, liver, and, breast tumors, and referred to as the "body" system. Using a porcine model we have previously demonstrated, using the body system, the ablative capacity and thermal transfer in the cortex; developed a reproducible and translational model of craniectomy and post-operative recovery in FUS; and determined a grouping strategy based on thermal ablation and pathologic incremental changes in the cortex. Here we describe a novel ExAblate 4000 system that is designed specifically to treat CNS disorders ("head" system). Twenty-two swine underwent an improved wide craniectomy for positioning of the ExAblate 4000 containing 1024 elements arrayed with MRI guidance. Further neurologic and pathological analysis was performed 1 week post-operatively. Subjects underwent a wide craniectomy followed by high intensity MR guided focused ultrasound (MRgHIFU) sonoablation. Thermal ultrasonic ablative lesions were achieved in all subjects (n=22) ranging from 52-65°C following ∼70 consecutive sonications at 80 watts. These subjects were grouped based on thermal ablative lesions and post-operative staging (MRI, gross and microscopic pathology). Our results indicate the reproducibility of a porcine model for cerebral ablation, achieved across a dynamic temperature range, and well tolerated in this cohort. The ExAblate 4000 system is efficient through a wide craniectomy as well as a closed skull and demonstrates a high safety margin. Incremental hemorrhage and necrosis were minimal and energy dependent, indicating MRgHIFU can be used for the treatment of various cerebral pathologies and movement disorders.
authors.affiliation: Department of Neurological Surgery, The Charles Clore Hospitalization Tower, West Wing Sheba Medical Center, Ramat Gan, Israel. Electronic address: zion.zivli@sheba.health.gov.il.
authors.forename: Zion
authors.initials: Z
authors.lastname: Zibly
authors.affiliation: Department of Pathology, Microbiology, and Immunology, 6439 Garners Ferry Rd., Building 1, Room C27, Columbia, SC 29209, USA.
authors.forename: Christian A
authors.initials: CA
authors.lastname: Graves
authors.affiliation: Department of Neurological Surgery, The Charles Clore Hospitalization Tower, West Wing Sheba Medical Center, Ramat Gan, Israel.
authors.forename: Sagi
authors.initials: S
authors.lastname: Harnof
authors.affiliation: Department of Neurological Surgery, The Charles Clore Hospitalization Tower, West Wing Sheba Medical Center, Ramat Gan, Israel.
authors.forename: Moshe
authors.initials: M
authors.lastname: Hadani
authors.affiliation: Department of Neurological Surgery, The Charles Clore Hospitalization Tower, West Wing Sheba Medical Center, Ramat Gan, Israel.
authors.forename: Zvi R
authors.initials: ZR
authors.lastname: Cohen
mesh_terms: D000818:Animals; D001921:Brain / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D003399:Craniotomy; D005260:Female; D057086:High-Intensity Focused Ultrasound Ablation / Q000295:instrumentation* / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D023421:Models, Animal; D015203:Reproducibility of Results; D025321:Surgery, Computer-Assisted / Q000379:methods*; D013552:Swine; D013696:Temperature
keywords: HIFU; MRgFUS; Neurosurgery; Preclinical model; Sonoablation