title: Transcranial magnetic resonance imaging- guided focused ultrasound surgery of brain tumors: initial findings in 3 patients.
abstract: OBJECTIVE
  This work evaluated the clinical feasibility of transcranial magnetic resonance imaging-guided focused ultrasound surgery.
  
  
  METHODS
  Transcranial magnetic resonance imaging-guided focused ultrasound surgery offers a potential noninvasive alternative to surgical resection. The method combines a hemispherical phased-array transducer and patient-specific treatment planning based on acoustic models with feedback control based on magnetic resonance temperature imaging to overcome the effects of the cranium and allow for controlled and precise thermal ablation in the brain. In initial trials in 3 glioblastoma patients, multiple focused ultrasound exposures were applied up to the maximum acoustic power available. Offline analysis of the magnetic resonance temperature images evaluated the temperature changes at the focus and brain surface.
  
  
  RESULTS
  We found that it was possible to focus an ultrasound beam transcranially into the brain and to visualize the heating with magnetic resonance temperature imaging. Although we were limited by the device power available at the time and thus seemed to not achieve thermal coagulation, extrapolation of the temperature measurements at the focus and on the brain surface suggests that thermal ablation will be possible with this device without overheating the brain surface, with some possible limitation on the treatment envelope.
  
  
  CONCLUSIONS
  Although significant hurdles remain, these findings are a major step forward in producing a completely noninvasive alternative to surgical resection for brain disorders.
authors.affiliation: Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA. njm@bwh.harvard.edu
authors.forename: Nathan
authors.initials: N
authors.lastname: McDannold
authors.forename: Greg T
authors.initials: GT
authors.lastname: Clement
authors.forename: Peter
authors.initials: P
authors.lastname: Black
authors.forename: Ferenc
authors.initials: F
authors.lastname: Jolesz
authors.forename: Kullervo
authors.initials: K
authors.lastname: Hynynen
mesh_terms: D000328:Adult; D001932:Brain Neoplasms / Q000628:therapy*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000379:methods*; D016896:Treatment Outcome; D014464:Ultrasonic Therapy; D055815:Young Adult