title: Usefulness of the advanced neuroimaging protocol based on plain and gadolinium-enhanced constructive interference in steady state images for gamma knife radiosurgery and planning microsurgical procedures for skull base tumors.
abstract: BACKGROUND
  Gamma Knife radiosurgery (GKS) is currently performed with 0.1 mm preciseness, which can be designated microradiosurgery. It requires advanced methods for visualizing the target, which can be effectively attained by a neuroimaging protocol based on plain and gadolinium-enhanced constructive interference in steady state (CISS) images.
  
  
  METHODS
  Since 2003, the following thin-sliced images are routinely obtained before GKS of skull base lesions in our practice: axial CISS, gadolinium-enhanced axial CISS, gadolinium-enhanced axial modified time-of-flight (TOF), and axial computed tomography (CT). Fusion of "bone window" CT and magnetic resonance imaging (MRI), and detailed three-dimensional (3D) delineation of the anatomical structures are performed with the Leksell GammaPlan (Elekta Instruments AB). Recently, a similar technique has been also applied to evaluate neuroanatomy before open microsurgical procedures.
  
  
  RESULTS
  Plain CISS images permit clear visualization of the cranial nerves in the subarachnoid space. Gadolinium-enhanced CISS images make the tumor "lucid" but do not affect the signal intensity of the cranial nerves, so they can be clearly delineated in the vicinity to the lesion. Gadolinium-enhanced TOF images are useful for 3D evaluation of the interrelations between the neoplasm and adjacent vessels. Fusion of "bone window" CT and MRI scans permits simultaneous assessment of both soft tissue and bone structures and allows 3D estimation and correction of MRI distortion artifacts.
  
  
  CONCLUSIONS
  Detailed understanding of the neuroanatomy based on application of the advanced neuroimaging protocol permits performance of highly conformal and selective radiosurgical treatment. It also allows precise planning of the microsurgical procedures for skull base tumors.
authors: Department of Neurosurgery, Neurological Institute, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo, 162-8666, Japan. gkrmoto@aol.com
authors: Motohiro
authors: M
authors: Hayashi
authors: Mikhail F
authors: MF
authors: Chernov
authors: Noriko
authors: N
authors: Tamura
authors: Shoji
authors: S
authors: Yomo
authors: Manabu
authors: M
authors: Tamura
authors: Ayako
authors: A
authors: Horiba
authors: Masahiro
authors: M
authors: Izawa
authors: Yoshihiro
authors: Y
authors: Muragaki
authors: Hiroshi
authors: H
authors: Iseki
authors: Yoshikazu
authors: Y
authors: Okada
authors: Pavel
authors: P
authors: Ivanov
authors: Jean
authors: J
authors: Régis
authors: Kintomo
authors: K
authors: Takakura
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D005682:Gadolinium; D006801:Humans; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D008297:Male; D008866:Microsurgery / Q000379:methods*; D008875:Middle Aged; D016634:Radiosurgery / Q000379:methods*; D019292:Skull Base Neoplasms / Q000175:diagnosis* / Q000601:surgery*
chemical_list: D005682:Gadolinium