title: Arcuate fasciculus tractography integrated into Gamma Knife surgery.
abstract: OBJECTIVE
  To prevent speech disturbances after Gamma Knife surgery (GKS), the authors integrated arcuate fasciculus (AF) tractography based on diffusion tensor (DT) MR imaging into treatment planning for GKS.
  
  
  METHODS
  Arcuate fasciculus tractography was retrospectively integrated into planning that had been previously performed by neurosurgeons and radiation oncologists. This technique was retrospectively applied to 12 patients with arteriovenous malformations adjacent to the AF. Diffusion tensor images were acquired before the frame was affixed to the patient's head and DT tractography images of the AF were created using the authors' original software. The data from DT tractography and stereotactic 3D imaging studies obtained after frame fixation were transported to a treatment planning workstation for GKS and coregistered so that the delivered doses and incidence of posttreatment aphasia could be assessed.
  
  
  RESULTS
  The AF could not be depicted in 2 patients who initially presented with motor aphasia caused by hemorrhaging from arteriovenous malformations. During the median follow-up period of 29 months after GKS, aphasia developed in 2 patients: 30 Gy delivered to the frontal portion of the AF caused conduction aphasia in 1 patient, and 9.6 Gy to the temporal portion led to motor aphasia in the other. Speech dysfunction was not observed after a maximum radiation dose of 10.0-16.8 Gy was delivered to the frontal fibers in 4 patients, and 3.6-5.2 Gy to the temporal fibers in 3.
  
  
  CONCLUSIONS
  The authors found that administration of a 10-Gy radiation dose during GKS was tolerated in the frontal but not the temporal fibers of the AF. The authors recommend confirmation of the dose by integration of AF tractography with GKS, especially in lesions located near the temporal language fibers.
authors.affiliation: Department of Neurosurgery, The University of Tokyo Hospital, Tokyo, Japan. kskmaru-tky@umin.ac.jp
authors.forename: Keisuke
authors.initials: K
authors.lastname: Maruyama
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Koga
authors.forename: Kyousuke
authors.initials: K
authors.lastname: Kamada
authors.forename: Takahiro
authors.initials: T
authors.lastname: Ota
authors.forename: Daisuke
authors.initials: D
authors.lastname: Itoh
authors.forename: Kenji
authors.initials: K
authors.lastname: Ino
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Igaki
authors.forename: Shigeki
authors.initials: S
authors.lastname: Aoki
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Masutani
authors.forename: Masahiro
authors.initials: M
authors.lastname: Shin
authors.forename: Nobuhito
authors.initials: N
authors.lastname: Saito
mesh_terms: D000328:Adult; D001037:Aphasia / Q000209:etiology; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications; D016634:Radiosurgery / Q000379:methods*; D012984:Software; D013064:Speech Disorders / Q000517:prevention & control*