title: Different magnetic resonance imaging patterns after transcranial magnetic resonance-guided focused ultrasound of the ventral intermediate nucleus of the thalamus and anterior limb of the internal capsule in patients with essential tremor or obsessive-compulsive disorder.
abstract: OBJECTIVE
  The authors report different MRI patterns in patients with essential tremor (ET) or obsessive-compulsive disorder (OCD) after transcranial MR-guided focused ultrasound (MRgFUS) and discuss possible causes of occasional MRgFUS failure.
  
  
  METHODS
  Between March 2012 and August 2013, MRgFUS was used to perform unilateral thalamotomy in 11 ET patients and bilateral anterior limb capsulotomy in 6 OCD patients; in all patients symptoms were refractory to drug therapy. Sequential MR images were obtained in patients across a 6-month follow-up period.
  
  
  RESULTS
  For OCD patients, lesion size slowly increased and peaked 1 week after treatment, after which lesion size gradually decreased. For ET patients, lesions were visible immediately after treatment and markedly reduced in size as time passed. In 3 ET patients and 1 OCD patient, there was no or little temperature rise (i.e., < 52°C) during MRgFUS. Successful and failed patient groups showed differences in their ratio of cortical-to-bone marrow thickness (i.e., skull density).
  
  
  CONCLUSIONS
  The authors found different MRI pattern evolution after MRgFUS for white matter and gray matter. Their results suggest that skull characteristics, such as low skull density, should be evaluated prior to MRgFUS to successfully achieve thermal rise.
authors.affiliation: Department of Neurosurgery, Brain Research Institute, Yonsei University College of Medicine, Seoul, Korea; and.
authors.forename: Hyun Ho
authors.initials: HH
authors.lastname: Jung
authors.forename: Won Seok
authors.initials: WS
authors.lastname: Chang
authors.forename: Itay
authors.initials: I
authors.lastname: Rachmilevitch
authors.forename: Tal
authors.initials: T
authors.lastname: Tlusty
authors.forename: Eyal
authors.initials: E
authors.lastname: Zadicario
authors.forename: Jin Woo
authors.initials: JW
authors.lastname: Chang
mesh_terms: D020329:Essential Tremor / Q000473:pathology / Q000601:surgery*; D006801:Humans; D020772:Internal Capsule / Q000473:pathology / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D019635:Neurosurgical Procedures / Q000379:methods*; D009771:Obsessive-Compulsive Disorder / Q000473:pathology / Q000601:surgery*; D012886:Skull / Q000601:surgery; D025321:Surgery, Computer-Assisted / Q000379:methods*; D013787:Thalamic Nuclei / Q000473:pathology / Q000601:surgery*; D017211:Treatment Failure; D059708:Ultrasonic Surgical Procedures / Q000379:methods*
keywords: ALIC = anterior limb of the internal capsule; ET = essential tremor; MR-guided focused ultrasound; MRI = magnetic resonance imaging; MRgFUS = magnetic resonance-guided focused ultrasound; OCD = obsessive-compulsive disorder; Vim = ventral intermediate; capsulotomy; essential tremor; functional neurosurgery; obsessive-compulsive disorder; skull density; thalamotomy