Michael L Schwartz1,2, Robert Yeung2,3, Yuexi Huang4, Nir Lipsman1,2, Vibhor Krishna5, Jennifer D Jain2, Martin G Chapman2,6, Andres M Lozano1,7, Kullervo Hynynen4,8,9. 1. 1Division of Neurosurgery and. 2. 2Sunnybrook Health Sciences Centre. 3. Departments of3Medical Imaging and. 4. 4Physical Sciences Platform, Sunnybrook Research Institute; and. 5. 5Department of Neurosurgery, The Ohio State University, Columbus, Ohio. 6. 6Anaesthesia. 7. 7Toronto Western Hospital, Toronto, Ontario, Canada; and. 8. 8Medical Biophysics, and. 9. 9Institute of Biomaterials and Biomedical Engineering, University of Toronto.
Abstract
OBJECTIVE: One patient for whom an MR-guided focused ultrasound (MRgFUS) pallidotomy was attempted was discovered to have multiple new skull lesions with the appearance of infarcts on the MRI scan 3 months after his attempted treatment. The authors conducted a retrospective review of the first 30 patients treated with MRgFUS to determine the incidence of skull lesions in patients undergoing these procedures and to consider possible causes. METHODS: A retrospective review of the MRI scans of the first 30 patients, 1 attempted pallidotomy and 29 ventral intermediate nucleus thalamotomies, was conducted. The correlation of the mean skull density ratio (SDR) and the maximum energy applied in the production or attempted production of a brain lesion was examined. RESULTS: Of 30 patients treated with MRgFUS for movement disorders, 7 were found to have new skull lesions that were not present prior to treatment and not visible on the posttreatment day 1 MRI scan. Discomfort was reported at the time of treatment by some patients with and without skull lesions. All patients with skull lesions were completely asymptomatic. There was no correlation between the mean SDR and the presence or absence of skull lesions, but the maximum energy applied with the Exablate system was significantly greater in patients with skull lesions than in those without. CONCLUSIONS: It is known that local skull density, thickness, and SDR vary from location to location. Sufficient energy transfer resulting in local heating sufficient to produce a bone lesion may occur in regions of low SDR. A correlation of lesion location and local skull properties should be made in future studies.
OBJECTIVE: One patient for whom an MR-guided focused ultrasound (MRgFUS) pallidotomy was attempted was discovered to have multiple new skull lesions with the appearance of infarcts on the MRI scan 3 months after his attempted treatment. The authors conducted a retrospective review of the first 30 patients treated with MRgFUS to determine the incidence of skull lesions in patients undergoing these procedures and to consider possible causes. METHODS: A retrospective review of the MRI scans of the first 30 patients, 1 attempted pallidotomy and 29 ventral intermediate nucleus thalamotomies, was conducted. The correlation of the mean skull density ratio (SDR) and the maximum energy applied in the production or attempted production of a brain lesion was examined. RESULTS: Of 30 patients treated with MRgFUS for movement disorders, 7 were found to have new skull lesions that were not present prior to treatment and not visible on the posttreatment day 1 MRI scan. Discomfort was reported at the time of treatment by some patients with and without skull lesions. All patients with skull lesions were completely asymptomatic. There was no correlation between the mean SDR and the presence or absence of skull lesions, but the maximum energy applied with the Exablate system was significantly greater in patients with skull lesions than in those without. CONCLUSIONS: It is known that local skull density, thickness, and SDR vary from location to location. Sufficient energy transfer resulting in local heating sufficient to produce a bone lesion may occur in regions of low SDR. A correlation of lesion location and local skull properties should be made in future studies.
Authors: Ning Lu; Timothy L Hall; Jonathan R Sukovich; Sang Won Choi; John Snell; Nathan McDannold; Zhen Xu Journal: Phys Med Biol Date: 2022-06-10 Impact factor: 4.174
Authors: M Anthony Phipps; Sumeeth V Jonathan; Pai-Feng Yang; Vandiver Chaplin; Li Min Chen; William A Grissom; Charles F Caskey Journal: Sci Rep Date: 2019-11-07 Impact factor: 4.379