title: Targeting accuracy of transcranial magnetic resonance-guided high-intensity focused ultrasound brain therapy: a fresh cadaver model.
abstract: OBJECTIVE
  This work aimed at evaluating the accuracy of MR-guided high-intensity focused ultrasound (MRgHIFU) brain therapy in human cadaver heads.
  
  
  METHODS
  Eighteen heads of fresh human cadavers were removed with a dedicated protocol preventing intracerebral air penetration. The MR images allowed determination of the ultrasonic target: a part of the thalamic nucleus ventralis intermedius implicated in essential tremor. Osseous aberrations were corrected with simulation-based time reversal by using CT data from the heads. The ultrasonic session was performed with a 512-element phased-array transducer system operating at 1 MHz under stereotactic conditions with thermometric real-time MR monitoring performed using a 1.5-T imager.
  
  
  RESULTS
  Dissection, imaging, targeting, and planning have validated the feasibility of this human cadaver model. The average temperature elevation measured by proton resonance frequency shift was 7.9°C ± 3°C. Based on MRI data, the accuracy of MRgHIFU is 0.4 ± 1 mm along the right/left axis, 0.7 ± 1.2 mm along the dorsal/ventral axis, and 0.5 ± 2.4 mm in the rostral/caudal axis.
  
  
  CONCLUSIONS
  Despite its limits (temperature, vascularization), the human cadaver model is effective for studying the accuracy of MRgHIFU brain therapy. With the 1-MHz system investigated here, there is millimetric accuracy.
authors: Department of Neurosurgery, Groupe Hospitalier Pitié Salpêtrière, Paris, France.
authors: Dorian
authors: D
authors: Chauvet
authors: Laurent
authors: L
authors: Marsac
authors: Mathieu
authors: M
authors: Pernot
authors: Anne-Laure
authors: AL
authors: Boch
authors: Rémy
authors: R
authors: Guillevin
authors: Najat
authors: N
authors: Salameh
authors: Line
authors: L
authors: Souris
authors: Luc
authors: L
authors: Darrasse
authors: Mathias
authors: M
authors: Fink
authors: Mickaël
authors: M
authors: Tanter
authors: Jean-François
authors: JF
authors: Aubry
mesh_terms: D002102:Cadaver; D020329:Essential Tremor / Q000000981:diagnostic imaging / Q000473:pathology / Q000628:therapy*; D005240:Feasibility Studies; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008953:Models, Anatomic; D014464:Ultrasonic Therapy / Q000379:methods*; D014463:Ultrasonography; D020651:Ventral Thalamic Nuclei / Q000000981:diagnostic imaging / Q000473:pathology