title: "Extraoperative" MRI (eoMRI) for Brain Tumor Surgery: Initial Results at a Single Institution.
abstract: BACKGROUND
  There is accumulating evidence that extent of resection (EOR) in intrinsic brain tumor surgery prolongs overall survival (OS) and progression-free survival (PFS). One of the strategies to increase EOR is the use of intraoperative MRI (ioMRI); however, considerable infrastructure investment is needed to establish and maintain a sophisticated ioMRI. We report the preliminary results of an extraoperative (eoMRI) protocol, with a focus on safety, feasibility, and EOR in intrinsic brain tumor surgery.
  
  
  METHODS
  Ten patients underwent an eoMRI protocol consisting of surgical resection in a conventional operating room followed by an immediate MRI in a clinical MRI scanner while the patient was still under anesthesia. If findings of the MRI suggested residual safely resectable tumor, the patient was returned to the operating room. A retrospective volumetric analysis was undertaken to investigate the percentage of tumor resected after first resection and if applicable, after further resection.
  
  
  RESULTS
  Six of 10 (60%) patients were thought to require no further resection after eoMRI. The EOR in these patients was 97.8% ± 1.8%. In the 4 patients who underwent further resection, the EOR during the original surgery was 88.5% ± 9.5% (P = 0.04). There was an average of 10.1% more tumor removed between the first and second surgery. In 3 of 4 (75%) of patients who returned for further resection, gross total resection of tumor was achieved.
  
  
  CONCLUSIONS
  An eoMRI protocol appears to be a safe and practical method to ensure maximum safe resections in patients with brain tumors and can be performed readily in all centers with MRI capabilities.
authors.affiliation: Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Muhammad M
authors.initials: MM
authors.lastname: Abd-El-Barr
authors.affiliation: Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Seth M
authors.initials: SM
authors.lastname: Santos
authors.affiliation: Department of Anesthesiology, Perioperative and Pain Management, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Linda S
authors.initials: LS
authors.lastname: Aglio
authors.affiliation: Section of Neuroradiology, Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Geoffrey S
authors.initials: GS
authors.lastname: Young
authors.affiliation: Section of Neuroradiology, Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Srinivasan
authors.initials: S
authors.lastname: Mukundan
authors.affiliation: Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA; Section of Neuroradiology, Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Alexandra J
authors.initials: AJ
authors.lastname: Golby
authors.affiliation: Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: William B
authors.initials: WB
authors.lastname: Gormley
authors.affiliation: Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA. Electronic address: idunn@partners.org.
authors.forename: Ian F
authors.initials: IF
authors.lastname: Dunn
mesh_terms: D000328:Adult; D001932:Brain Neoplasms / Q000473:pathology* / Q000601:surgery*; D018572:Disease-Free Survival; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D018365:Neoplasm, Residual / Q000453:epidemiology / Q000469:parasitology; D019635:Neurosurgical Procedures; D012189:Retrospective Studies; D016019:Survival Analysis; D016896:Treatment Outcome; D055815:Young Adult
keywords: Brain tumor; Magnetic resonance imaging; Surgery