title: Intraoperative tissue fluorescence using 5-aminolevolinic acid (5-ALA) is more sensitive than contrast MRI or amino acid positron emission tomography ((18)F-FET PET) in glioblastoma surgery.
abstract: OBJECTIVE
  The sensitivity of 5-aminolevolinic acid (5-ALA) in detecting intraoperative glioblastoma (GBM) tissue compared to postoperative (18)F-fluoroethyl-L-tyrosine and T1 contrast uptake of tumor cells in positron emission tomography (PET) and  magnetic resonance imaging (MRI) scans was investigated in a retrospective image correlative study.
  
  
  METHODS
  Ten patients with histological verified GBM in eloquent brain regions underwent 11 surgeries with neuronavigation and 5-ALA assisted tumor resection. Residual 5-ALA fluorescence  was labeled intraoperatively on the navigation MRI scans and images were fused with postoperative (18)F-FET PET and T1 contrast MRI.
  
  
  RESULTS
  Intraoperatively, at the end of save resection, in all patients 2-5 faint 5-ALA positive resection planes were detected (mean  3·6), compared to 0-4 (18)F-FET positive resection planes (mean 1·4) and 0-2 positive T1 contrast MRI resection planes in postoperative scans. The difference between the number of 5-ALA and (18)F-FET positive resection planes was statistically  significant (P = 0·0002). The histological investigation of 5-ALA positive resection margins demonstrated infiltrative tumor in every case. Residual 5-ALA fluorescence on resection margins and postoperative (18)F-FET uptake areas or residual contrast T1 areas  were colocalized in all cases, documented by pre-/postoperative image fusion.
  
  
  CONCLUSIONS
  Residual faint 5ALA uptake is documented in large areas at the end of GBM resection and corresponds to tumor infiltration. These 5-ALA positive resection plans exceeded the (18)F-FET  uptake areas in postoperative PET scans. Thus, intraoperative 5-ALA residual fluorescence seems to be a more sensitive marker than (18)F-FET PET for residual tumor in malignant gliomas.
authors.affiliation: Department of Neurosurgery, Academic Teaching Hospital, Feldkirch, Austria.
authors.forename: Karl
authors.initials: K
authors.lastname: Roessler
authors.forename: Alexander
authors.initials: A
authors.lastname: Becherer
authors.forename: Markus
authors.initials: M
authors.lastname: Donat
authors.forename: Manfred
authors.initials: M
authors.lastname: Cejna
authors.forename: Iris
authors.initials: I
authors.lastname: Zachenhofer
mesh_terms: D000328:Adult; D000368:Aged; D000622:Aminolevulinic Acid; D001932:Brain Neoplasms / Q000473:pathology / Q000601:surgery*; D003287:Contrast Media; D005260:Female; D005456:Fluorescent Dyes; D005909:Glioblastoma / Q000473:pathology / Q000601:surgery*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D018365:Neoplasm, Residual / Q000175:diagnosis*; D038361:Neuronavigation; D049268:Positron-Emission Tomography; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; D005456:Fluorescent Dyes; D000622:Aminolevulinic Acid