title: Arterial spin labeling: Pathologically proven superiority over conventional MRI for detection of high-grade glioma progression after treatment.
abstract: BACKGROUND
  Standard of care for high-grade gliomas (HGGs) includes surgical debulking and adjuvant chemotherapy and radiation. Patients under treatment require frequent clinical and imaging monitoring for therapy modulation. Differentiating tumor progression from treatment-related changes can be challenging on conventional MRI, resulting in delayed recognition of tumor progression. Arterial spin labeling (ASL) may be more sensitive for tumor progression.
  
  
  METHODS
  ASL and associated conventional MR images obtained in patients previously treated for HGGs and before biopsy or re-resection were reviewed by three neuroradiologists who were blinded to the histopathologic results. Regions of interest (ROIs) of greatest perfusion were chosen by consensus, and mirror-image contralateral ROIs were also placed. Sensitivity of ASL for tumor progression was compared with those of contrast-enhanced T1-weighted (T1W-CE) and fluid-attenuated inversion recovery (FLAIR) images using McNemar's test. We tested for an association between cerebral blood flow (CBF) and apparent diffusion correlation (ADC) using a Hotelling-Lawley trace. Finally, we used a Pearson's analysis to test for a correlation between CBF and percentage of tumor within each resection.
  
  
  RESULTS
  Twenty-two patients were studied. ASL demonstrated hyperperfusion in all cases with mean CBF ratio 3.37 (±1.71). T1W-CE and FLAIR images were positive in 15 (p = 0.0233) and 16 (p = 0.0412) cases, respectively. There was no association between ADC and CBF (p = 0.687). There was a correlation between CBF and percentage of tumor (p = 0.048).
  
  
  CONCLUSIONS
  ASL may be more sensitive than conventional MR sequences for the detection of tumor progression in patients treated for HGGs.
authors.affiliation: Department of Radiology, University of Colorado Hospital, USA Eric.nyberg@ucdenver.edu.
authors.forename: Eric
authors.initials: E
authors.lastname: Nyberg
authors.affiliation: Department of Radiology, University of Colorado Hospital, USA.
authors.forename: Justin
authors.initials: J
authors.lastname: Honce
authors.affiliation: Departments of Pathology, Neurology and Neurosurgery, University of Colorado Hospital, USA.
authors.forename: Bette K
authors.initials: BK
authors.lastname: Kleinschmidt-DeMasters
authors.affiliation: Department of Radiology, University of Colorado Hospital, USA.
authors.forename: Brian
authors.initials: B
authors.lastname: Shukri
authors.affiliation: Neptune and Company Inc, USA.
authors.forename: Sarah
authors.initials: S
authors.lastname: Kreidler
authors.affiliation: Department of Radiology, University of Colorado Hospital, USA.
authors.forename: Lidia
authors.initials: L
authors.lastname: Nagae
mesh_terms: D001932:Brain Neoplasms / Q000000981:diagnostic imaging*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D003287:Contrast Media; D018450:Disease Progression; D005260:Female; D005910:Glioma / Q000000981:diagnostic imaging*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D013113:Spin Labels
chemical_list: D003287:Contrast Media; D013113:Spin Labels
keywords: Arterial spin labeling; MR perfusion; glioblastoma; pseudoprogression; radiation necrosis