title: Dynamic 18F-FET PET in newly diagnosed astrocytic low-grade glioma identifies high-risk patients.
abstract: Because the clinical course of low-grade gliomas in the individual adult patient varies considerably and is unpredictable, we investigated the prognostic value of dynamic (18)F-fluorethyltyrosine ((18)F-FET) PET in the early diagnosis of astrocytic low-grade glioma (World Health Organization grade II).
  
  
  METHODS
  Fifty-nine patients with newly diagnosed low-grade glioma and dynamic (18)F-FET PET before histopathologic assessment were retrospectively investigated. (18)F-FET PET analysis comprised a qualitative visual classification of lesions; assessment of the semiquantitative parameters maximal, mean, and total standardized uptake value as ratio to background and biologic tumor volume; and dynamic analysis of intratumoral (18)F-FET uptake over time (increasing vs. decreasing time-activity curves). The correlation between PET parameters and progression-free survival, overall survival, and time to malignant transformation was investigated.
  
  
  RESULTS
  (18)F-FET uptake greater than the background level was found in 34 of 59 tumors. Dynamic (18)F-FET uptake analysis was available for 30 of these 34 patients. Increasing and decreasing time-activity curves were found in 18 and 12 patients, respectively. Neither the qualitative factor presence or absence of (18)F-FET uptake nor any of the semiquantitative uptake parameters significantly influenced clinical outcome. In contrast, decreasing time-activity curves in the kinetic analysis were highly prognostic for shorter progression-free survival and time to malignant transformation (P < 0.001).
  
  
  CONCLUSIONS
  Absence of (18)F-FET uptake in newly diagnosed astrocytic low-grade glioma does not generally indicate an indolent disease course. Among the (18)F-FET-positive gliomas, decreasing time-activity curves in dynamic (18)F-FET PET constitute an unfavorable prognostic factor in astrocytic low-grade glioma and, by identifying high-risk patients, may ease treatment decisions.
authors.affiliation: Department of Nuclear Medicine, University of Munich, Munich, Germany.
authors.forename: Nathalie L
authors.initials: NL
authors.lastname: Jansen
authors.forename: Bogdana
authors.initials: B
authors.lastname: Suchorska
authors.forename: Vera
authors.initials: V
authors.lastname: Wenter
authors.forename: Sabina
authors.initials: S
authors.lastname: Eigenbrod
authors.forename: Christine
authors.initials: C
authors.lastname: Schmid-Tannwald
authors.forename: Andreas
authors.initials: A
authors.lastname: Zwergal
authors.forename: Maximilian
authors.initials: M
authors.lastname: Niyazi
authors.forename: Mark
authors.initials: M
authors.lastname: Drexler
authors.forename: Peter
authors.initials: P
authors.lastname: Bartenstein
authors.forename: Oliver
authors.initials: O
authors.lastname: Schnell
authors.forename: Jörg-Christian
authors.initials: JC
authors.lastname: Tonn
authors.forename: Niklas
authors.initials: N
authors.lastname: Thon
authors.forename: Friedrich-Wilhelm
authors.initials: FW
authors.lastname: Kreth
authors.forename: Christian
authors.initials: C
authors.lastname: la Fougère
mesh_terms: D000328:Adult; D001253:Astrocytes / Q000000981:diagnostic imaging* / Q000473:pathology; D001932:Brain Neoplasms / Q000000981:diagnostic imaging* / Q000401:mortality; D018450:Disease Progression; D018572:Disease-Free Survival; D005260:Female; D005910:Glioma / Q000000981:diagnostic imaging* / Q000401:mortality; D006801:Humans; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D011379:Prognosis; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D012306:Risk; D013997:Time Factors; D016896:Treatment Outcome; D014443:Tyrosine / Q000031:analogs & derivatives*
chemical_list: D019275:Radiopharmaceuticals; C545932:(18F)fluoroethyltyrosine; D014443:Tyrosine
keywords: FET-PET; kinetic analysis; low grade glioma; prognostic value