title: Association of F18-fluoro-ethyl-tyrosin uptake and 5-aminolevulinic acid-induced fluorescence in gliomas.
abstract: OBJECTIVE
  Malignant gliomas are highly infiltrative tumours with a fatal prognosis. F18-fluoroethyl-tyrosine (FET)-positron emission tomography (PET) often reveals a broader extension of these tumours compared with contrast-enhanced magnetic resonance imaging (MRI). Complete resection of the contrast-enhancing lesion is aspired. Fluorescence-guided resection using 5-aminolevulinic acid (5-ALA) improved the extent of resection. In this study, we investigated whether the FET uptake correlates with the extent of resection using 5-ALA-induced fluorescence.
  
  
  METHODS
  Thirteen patients who underwent preoperative and postoperative MRI, FET-PET and fluorescence-guided neuronavigated resection were included in this study. The areas in which intraoperative fluorescence terminated the resection were marked. After fusion of PET and MRI, the standardized uptake value (SUV) of FET related to normal brain (SUV(R)) was measured in regions of interest corresponding to resected and remaining tissue, respectively. Receiver-operating characteristic (ROC) curve analysis determined the optimal threshold of the relative SUV anticipating 5-ALA-induced fluorescence.
  
  
  RESULTS
  During resection a vivid fluorescence was present in all patients. Histology revealed glioblastomas in 11 cases, an anaplastic astrocytoma in one case and a low-grade astrocytoma in one case. The median FET SUV(R) was higher in areas corresponding to the fluorescent tumour compared with the non-fluorescent normal brain (2.321 vs 1.142, p < 0.0001, t-test). A SUV(R) greater than 1.374 predicted the fluorescence with a sensitivity of 0.87 [95% confidence interval (CI): 0.74-0.94] and a specificity of 0.94 (CI: 0.84-0.99). The area under the ROC curve was 0.9656 (CI: 0.9364-0.9948).
  
  
  CONCLUSIONS
  FET uptake predicts the 5-ALA-induced fluorescence in glioma patients. Thus, FET-PET provides useful information for planning glioma resection.
authors.affiliation: Department of Neurosurgery, Charité Universitätsmedizin Berlin, 13353 Berlin, Germany. florian.stockhammer@charite.de
authors.forename: Florian
authors.initials: F
authors.lastname: Stockhammer
authors.forename: Martin
authors.initials: M
authors.lastname: Misch
authors.forename: Peter
authors.initials: P
authors.lastname: Horn
authors.forename: Arend
authors.initials: A
authors.lastname: Koch
authors.forename: Nyuyki
authors.initials: N
authors.lastname: Fonyuy
authors.forename: Michail
authors.initials: M
authors.lastname: Plotkin
mesh_terms: D000328:Adult; D000368:Aged; D000622:Aminolevulinic Acid / Q000032:analysis* / Q000378:metabolism; D014408:Biomarkers, Tumor / Q000032:analysis / Q000378:metabolism*; D001932:Brain Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000601:surgery; D005260:Female; D005453:Fluorescence; D005910:Glioma / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000601:surgery; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods; D038361:Neuronavigation / Q000379:methods; D019635:Neurosurgical Procedures / Q000379:methods; D049268:Positron-Emission Tomography / Q000379:methods*; D011237:Predictive Value of Tests; D011300:Preoperative Care / Q000379:methods; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000032:analysis / Q000378:metabolism
chemical_list: D014408:Biomarkers, Tumor; C117289:O-(2-fluoroethyl)tyrosine; D014443:Tyrosine; D000622:Aminolevulinic Acid