title: ²³Na-MRI of recurrent glioblastoma multiforme after intraoperative radiotherapy: technical note.
abstract: BACKGROUND
  We report the first case of an intraoperative radiotherapy (IORT) in a patient with recurrent glioblastoma multiforme (GBM) who was followed up with a novel magnetic resonance imaging (MRI) method-(23)Na-MRI-in comparison to a standard contrast-enhanced (1)H-MRI and (18)F-FET-PET.
  
  
  METHODS
  A 56-year-old female patient with diagnosed GBM in July 2012 underwent tumor resection, radiochemotherapy, and three cycles of chemotherapy. After a relapse, 6 months after the initial diagnosis, an IORT was recommended which was performed in March 2013 using the INTRABEAM system (Carl Zeiss Meditec AG, Germany) with a 3-cm applicator and a surface dose of 20 Gy. Early post-operative contrast-enhanced and 1-month follow-up (1)H-MRI and a (18)F-FET-PET were performed. In addition, an IRB-approved (23)Na-MRI was performed on a 3.0-T MR scanner (MAGNETOM TimTrio, Siemens Healthcare, Germany).
  
  
  RESULTS
  After re-surgery and IORT in March 2013, only a faint contrast enhancement but considerable surrounding edema was visible at the medio-posterior resection margins. In April 2013, new and progressive contrast enhancement, edema, (23)Na content, and increased uptake in the (18)F-FET-PET were visible, indicating tumor recurrence. Increased sodium content within the area of contrast enhancement was found in the (23)Na-MRI, but also exceeding this area, very similar to the increased uptake depicted in the (18)F-FET-PET. The clearly delineable zone of edema in both examinations exhibits a lower (23)Na content compared to areas with suspected proliferating tumor tissue.
  
  
  CONCLUSIONS
  (23)Na-MRI provided similar information in the suspicious area compared to (18)F-FET-PET, exceeding conventional (1)H-MRI. Still, (23)Na-MRI remains an investigational technique, which is worth to be further evaluated.
authors.affiliation: Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Haneder
authors.forename: Frank A
authors.initials: FA
authors.lastname: Giordano
authors.forename: Simon
authors.initials: S
authors.lastname: Konstandin
authors.forename: Stefanie
authors.initials: S
authors.lastname: Brehmer
authors.forename: Karen A
authors.initials: KA
authors.lastname: Buesing
authors.forename: Peter
authors.initials: P
authors.lastname: Schmiedek
authors.forename: Lothar R
authors.initials: LR
authors.lastname: Schad
authors.forename: Frederik
authors.initials: F
authors.lastname: Wenz
authors.forename: Stefan O
authors.initials: SO
authors.lastname: Schoenberg
authors.forename: Melissa M
authors.initials: MM
authors.lastname: Ong
mesh_terms: D001932:Brain Neoplasms / Q000473:pathology* / Q000628:therapy*; D003131:Combined Modality Therapy; D003287:Contrast Media; D016371:Cranial Irradiation / Q000379:methods; D005260:Female; D005909:Glioblastoma / Q000473:pathology* / Q000628:therapy*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000473:pathology* / Q000628:therapy*; D019635:Neurosurgical Procedures; D019275:Radiopharmaceuticals; D012975:Sodium Isotopes / Q000627:therapeutic use; D016896:Treatment Outcome
chemical_list: D003287:Contrast Media; D019275:Radiopharmaceuticals; D012975:Sodium Isotopes