title: Identification of disappearing brain lesions with intraoperative magnetic resonance imaging prevents surgery.
abstract: BACKGROUND
  Typically, neurosurgery is performed several weeks after diagnostic imaging. In the majority of cases, histopathology confirms the diagnosis of neoplasia. In a small number of cases, a different diagnosis is established or histopathology is nondiagnostic. The frequency with which these outcomes occur has not been established.
  
  
  OBJECTIVE
  To determine the frequency and outcome of disappearing brain lesions within a group of patients undergoing surgery for suspected brain tumor.
  
  
  METHODS
  Over the past decade, 982 patients were managed in the intraoperative magnetic resonance imaging unit at the University of Calgary, Calgary, Alberta, Canada. These patients have been prospectively evaluated.
  
  
  RESULTS
  In 652 patients, a brain tumor was suspected. In 6 of the 652 patients, histopathology indicated a nontumor diagnosis. In 5 patients, intraoperative images, acquired after induction of anesthesia, showed complete or nearly complete resolution of the suspected tumor identified on diagnostic magnetic resonance imaging acquired 6 ± 4 (mean ± SD) weeks previously. Anesthesia was reversed, and the surgical procedure aborted. The lesions have not progressed with 6 ± 2 years of follow-up.
  
  
  CONCLUSIONS
  Intraoperative magnetic resonance imaging prevented surgery on 5 patients with disappearing lesions.
authors.affiliation: Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Christina S
authors.initials: CS
authors.lastname: Sutherland
authors.forename: John Jp
authors.initials: JJ
authors.lastname: Kelly
authors.forename: William
authors.initials: W
authors.lastname: Morrish
authors.forename: Garnette R
authors.initials: GR
authors.lastname: Sutherland
mesh_terms: D000328:Adult; D001921:Brain / Q000473:pathology*; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000601:surgery*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D016343:Monitoring, Intraoperative / Q000379:methods*; D009493:Neurosurgery / Q000379:methods*; D012189:Retrospective Studies