title: Glioma recurrence versus radiation necrosis? A pilot comparison of arterial spin-labeled, dynamic susceptibility contrast enhanced MRI, and FDG-PET imaging.
abstract: OBJECTIVE
  Distinguishing recurrent glial tumor from radiation necrosis can be challenging. The purpose of this pilot study was to preliminarily compare unenhanced arterial spin-labeled (ASL) imaging, dynamic susceptibility contrast-enhanced cerebral blood volume (DSCE-CBV) magnetic resonance imaging, and positron emission tomographic (PET) imaging in distinguishing predominant glioma recurrence or progression from predominant radiation necrosis in postoperative patients treated with proton-beam therapy.
  
  
  METHODS
  Patients with grade II to IV glioma previously treated with surgery and proton-beam therapy were enrolled on the basis of new enhancing nodules or masses with primary differential diagnoses of predominant tumor recurrence or progression versus radiation necrosis. ASL, DSCE-CBV, and PET examinations were assessed by visual qualitative and quantitative analysis for the detection of predominant tumor recurrence. Imaging results were correlated with a clinical-pathologic reference standard.
  
  
  RESULTS
  Thirty patients were studied, resulting in 33 ASL, 32 DSCE-CBV, and 26 PET examinations. On the basis of visual inspection, the sensitivities of PET, ASL, and DSCE-CBV examinations for detecting high-grade tumor foci were 81%, 88%, and 86%, respectively. The highest sensitivity values for quantitative ASL imaging were obtained using a normalized cutoff ratio of 1.3, resulting in sensitivity of 94% for ASL imaging and 71% for DSCE-CBV imaging. When predominant high-grade tumors with superimposed regions of predominant mixed radiation necrosis were excluded, DSCE-CBV sensitivity improved to 90%, but ASL sensitivity remained unchanged.
  
  
  CONCLUSIONS
  Compared with DSCE-CBV imaging, ASL imaging may more accurately distinguish predominant recurrent high-grade glioma from radiation necrosis, especially in regions with mixed radiation necrosis, for which DSCE-CBV imaging may underestimate true blood volume because of leakage artifacts.
authors.affiliation: Department of Radiology, Adnan Menderes University, School of Medicine, Hastane Caddesi, Aydin, Turkey. yeldaozsunar@gmail.com
authors.forename: Yelda
authors.initials: Y
authors.lastname: Ozsunar
authors.forename: Mark E
authors.initials: ME
authors.lastname: Mullins
authors.forename: Kenneth
authors.initials: K
authors.lastname: Kwong
authors.forename: Fred H
authors.initials: FH
authors.lastname: Hochberg
authors.forename: Christine
authors.initials: C
authors.lastname: Ament
authors.forename: Pamela W
authors.initials: PW
authors.lastname: Schaefer
authors.forename: R Gilberto
authors.initials: RG
authors.lastname: Gonzalez
authors.forename: Michael H
authors.initials: MH
authors.lastname: Lev
mesh_terms: D000328:Adult; D000368:Aged; D001930:Brain Injuries / Q000175:diagnosis* / Q000209:etiology; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000532:radiotherapy; D003287:Contrast Media; D005260:Female; D019788:Fluorodeoxyglucose F18; D005682:Gadolinium; D005910:Glioma / Q000175:diagnosis* / Q000532:radiotherapy; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009336:Necrosis / Q000175:diagnosis / Q000209:etiology; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis* / Q000532:radiotherapy; D010865:Pilot Projects; D049268:Positron-Emission Tomography / Q000379:methods*; D011832:Radiation Injuries / Q000175:diagnosis* / Q000209:etiology; D019275:Radiopharmaceuticals; D011878:Radiotherapy / Q000009:adverse effects; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013113:Spin Labels; D055815:Young Adult
chemical_list: D003287:Contrast Media; D019275:Radiopharmaceuticals; D013113:Spin Labels; D019788:Fluorodeoxyglucose F18; D005682:Gadolinium