title: Pseudoprogression in patients with glioblastoma: added value of arterial spin labeling to dynamic susceptibility contrast perfusion MR imaging.
abstract: BACKGROUND
  Pseudoprogression is a treatment-related reaction with an increase in contrast-enhancing lesion size, followed by subsequent improvement. Differentiating tumor recurrence from pseudoprogression remains a problem in neuro-oncology.
  
  
  OBJECTIVE
  To validate the added value of arterial spin labeling (ASL), compared with dynamic susceptibility contrast (DSC) perfusion magnetic resonance imaging (MRI) alone, in distinguishing early tumor progression from pseudoprogression in patients with newly diagnosed glioblastoma multiforme (GBM).
  
  
  METHODS
  We retrospectively evaluated 117 consecutive patients with newly diagnosed GBM who underwent surgical resection and concurrent chemoradiotherapy (CCRT) as standard treatment modality. Sixty-two patients who developed contrast-enhancing lesions were assessed by both ASL and DSC perfusion MRI and classified into groups of early tumor recurrence (n = 34) or pseudoprogression (n = 28) based on pathologic analysis or clinical-radiologic follow-up. We used a qualitative analysis and semi-quantitative grade system on the basis of the tumor perfusion signal intensity into those equal to white matter (grade I), gray matter (grade II), and blood vessels (grade III) on ASL imaging. ASL grade was correlated with histogram parameters derived from DSC perfusion MRI.
  
  
  RESULTS
  Pseudoprogression was observed in 15 (53.6%) patients with ASL grade I, 13 (46.4%) with grade II, and 0 (0%) with grade III, with early tumor progression observed in seven (20.6%) patients with ASL grade I, 11 (32.3%) with grade II, and 16 (47.1%) with grade III (P = 0.0022). DSC perfusion histogram parameters differed significantly among ASL grades. ASL grade was an independent predictor differentiating pseudoprogression from early tumor progression (odds ratio, 4.73; P = 0.0017). On qualitative review, adjunctive ASL produced eight (12.9%) more accurate results than DSC perfusion MRI alone.
  
  
  CONCLUSIONS
  ASL improves the diagnostic accuracy of DSC perfusion MRI in differentiating pseudoprogression from early tumor progression.
authors.affiliation: Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul.
authors.forename: Young Jun
authors.initials: YJ
authors.lastname: Choi
authors.affiliation: Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul radhskim@gmail.com.
authors.forename: Ho Sung
authors.initials: HS
authors.lastname: Kim
authors.affiliation: Department of Radiology, Kyung Hee University Hospital-Gangdong, School of Medicine, Kyung Hee University, Seoul, South Korea.
authors.forename: Geon-Ho
authors.initials: GH
authors.lastname: Jahng
authors.affiliation: Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul.
authors.forename: Sang Joon
authors.initials: SJ
authors.lastname: Kim
authors.affiliation: Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul.
authors.forename: Dae Chul
authors.initials: DC
authors.lastname: Suh
mesh_terms: D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000473:pathology* / Q000628:therapy; D003131:Combined Modality Therapy; D003287:Contrast Media; D018450:Disease Progression; D005260:Female; D019786:Gadolinium DTPA; D005909:Glioblastoma / Q000473:pathology* / Q000628:therapy; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D011379:Prognosis; D012189:Retrospective Studies; D013113:Spin Labels
chemical_list: D003287:Contrast Media; D013113:Spin Labels; D019786:Gadolinium DTPA
keywords: Brain; MRI; perfusion; recurrence; tumor