title: Comparison of temperature processing methods for monitoring focused ultrasound ablation in the brain.
abstract: OBJECTIVE
  To investigate the performance of different reconstruction methods for monitoring temperature changes during transcranial magnetic resonance imaging (MRI)-guided focused ultrasound (MRgFUS).
  
  
  METHODS
  Four different temperature reconstruction methods were compared in volunteers (without heating) and patients undergoing transcranial MRgFUS: single baseline subtraction, multibaseline subtraction, hybrid single baseline/referenceless reconstruction, and hybrid multibaseline/referenceless reconstruction. Absolute temperature error and temporal temperature uncertainty of the different reconstruction methods were analyzed and compared.
  
  
  RESULTS
  Absolute temperature errors and temporal temperature uncertainty were highest with single baseline subtraction and lowest with hybrid multibaseline/referenceless reconstruction in all areas of the brain. Pulsation of the brain and susceptibility changes from tongue motion or swallowing caused substantial temperature errors when single or multibaseline subtraction was used, which were much reduced when the referenceless component was added to the reconstruction.
  
  
  CONCLUSIONS
  Hybrid multibaseline/referenceless thermometry accurately measures temperature changes in the brain with fewer artifacts and errors due to motion than pure baseline subtraction methods.
authors.affiliation: Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California, USA.
authors.forename: Viola
authors.initials: V
authors.lastname: Rieke
authors.forename: Ron
authors.initials: R
authors.lastname: Instrella
authors.forename: Jarrett
authors.initials: J
authors.lastname: Rosenberg
authors.forename: William
authors.initials: W
authors.lastname: Grissom
authors.forename: Beat
authors.initials: B
authors.lastname: Werner
authors.forename: Ernst
authors.initials: E
authors.lastname: Martin
authors.forename: Kim Butts
authors.initials: KB
authors.lastname: Pauly
mesh_terms: D000465:Algorithms; D001921:Brain / Q000033:anatomy & histology* / Q000601:surgery*; D057086:High-Intensity Focused Ultrasound Ablation / Q000379:methods*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D025321:Surgery, Computer-Assisted / Q000379:methods*; D013817:Thermography / Q000379:methods*
keywords: HIFU; MR thermometry; MRgFUS; motion; transcranial
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