title: Diffusion changes in a tumor and peritumoral tissue after stereotactic irradiation for brain tumors: possible prediction of treatment response.
abstract: OBJECTIVE
  Changes in apparent diffusion coefficient (ADC) in a tumor and peritumoral tissue after stereotactic irradiation (STI) were evaluated, and then the therapeutic efficacy of ADC measurement was assessed.
  
  
  METHODS
  In 20 tumors, diffusion-weighted imaging within 1 week before and 2-4 weeks after STI was performed. The normalized ADC (nADC) was measured. The nADCs in the tumor and peritumoral region before STI were compared with those after STI and the change in tumor nADC compared with the change in tumor size.
  
  
  RESULTS
  The nADC of the tumors was significantly higher 2-4 weeks after STI compared with that before STI. The nADC of the peritumoral regions 2-4 weeks after STI did not differ significantly from that before STI. A significant difference in the nADC at 2-4 weeks after STI was observed between the responder and nonresponder groups.
  
  
  CONCLUSIONS
  Changes in nADC as measured by diffusion-weighted imaging can predict response to STI.
authors.affiliation: Department of Radiology, Akita University School of Medicine, and Department of Radiology, Akita University Hospital, Japan. tomura@med.akita-u.ac.jp
authors.forename: Noriaki
authors.initials: N
authors.lastname: Tomura
authors.forename: Komei
authors.initials: K
authors.lastname: Narita
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Izumi
authors.forename: Akira
authors.initials: A
authors.lastname: Suzuki
authors.forename: Akira
authors.initials: A
authors.lastname: Anbai
authors.forename: Takahiro
authors.initials: T
authors.lastname: Otani
authors.forename: Ikuo
authors.initials: I
authors.lastname: Sakuma
authors.forename: Satoshi
authors.initials: S
authors.lastname: Takahashi
authors.forename: Kazuo
authors.initials: K
authors.lastname: Mizoi
authors.forename: Jiro
authors.initials: J
authors.lastname: Watarai
mesh_terms: D001932:Brain Neoplasms / Q000175:diagnosis* / Q000532:radiotherapy* / Q000556:secondary; D002817:Chordoma / Q000175:diagnosis / Q000532:radiotherapy; D038524:Diffusion Magnetic Resonance Imaging; D005909:Glioblastoma / Q000175:diagnosis / Q000532:radiotherapy; D006801:Humans; D008223:Lymphoma / Q000175:diagnosis / Q000532:radiotherapy; D008579:Meningioma / Q000175:diagnosis / Q000532:radiotherapy; D009442:Neurilemmoma / Q000175:diagnosis / Q000532:radiotherapy; D018242:Neuroectodermal Tumors, Primitive / Q000175:diagnosis / Q000532:radiotherapy; D011878:Radiotherapy / Q000379:methods