title: Differentiation of hemangioblastomas from pilocytic astrocytomas using 3-T magnetic resonance perfusion-weighted imaging and MR spectroscopy.
abstract: BACKGROUND
  Hemangioblastomas and pilocytic astrocytomas (PAs) present similar imaging features on conventional MR imaging, making differential diagnosis a challenge. The purpose of this study was to evaluate the usefulness of dynamic susceptibility-weighted contrast-enhanced perfusion-weighted imaging (DSC-PWI) and proton MR spectroscopic imaging in the differentiation of hemangioblastomas and PAs.
  
  
  METHODS
  A 3.0-T MR imaging unit was used to perform DSC-PWI and conventional MR imaging on 14 patients with hemangioblastomas and 22 patients with PAs. Four patients with hemangioblastomas and 10 PA patients also underwent proton MR spectroscopy. Parameters of relative peak height (rPH) and relative percentage of signal intensity recovery (rPSR) were acquired by DSC-PWI and variables of N-acetylaspasrtate (NAA)/creatine (Cr), choline (Cho)/Cr, and lactate-lipid (Lac-Lip)/Cr by MR spectroscopy. The sensitivity, specificity, and the area under the receiver operating characteristic curve of all analyzed parameters at respective cutoff values were determined.
  
  
  RESULTS
  Higher rPH but lower rPSR values were detected in hemangioblastomas compared to PAs. The NAA/Cr ratio was significantly lower in hemangioblastomas compared with PAs. The threshold values ≥3.2 for rPH provide sensitivity, specificity, positive predictive values, and negative predictive values of 85.7, 95.5, 92.3, and 91.3%, respectively, for differentiating hemangioblastomas from PAs. The optimal threshold values were ≤0.9 for rPSR and ≤1.5 for NAA/Cr ratios in tumor.
  
  
  CONCLUSIONS
  Significantly higher rPH and lower NAA/Cr were seen in patients with hemangioblastomas when compared with PA patients, suggesting that DSC-PWI and proton MR spectroscopy are helpful in the characterization and differentiation of these two types of tumors.
authors.affiliation: Department of Radiology, First Affiliated Hospital of Fujian Medical University, 20 Cha-Zhong Road, Fuzhou, Fujian, 350005, People's Republic of China.
authors.forename: D J
authors.initials: DJ
authors.lastname: She
authors.forename: Z
authors.initials: Z
authors.lastname: Xing
authors.forename: Z
authors.initials: Z
authors.lastname: Zeng
authors.forename: X Y
authors.initials: XY
authors.lastname: Shang
authors.forename: D R
authors.initials: DR
authors.lastname: Cao
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001254:Astrocytoma / Q000737:chemistry / Q000175:diagnosis*; D014408:Biomarkers, Tumor / Q000032:analysis*; D001932:Brain Neoplasms / Q000737:chemistry / Q000175:diagnosis*; D002648:Child; D002675:Child, Preschool; D003936:Diagnosis, Computer-Assisted / Q000379:methods; D003937:Diagnosis, Differential; D005260:Female; D018325:Hemangioblastoma / Q000737:chemistry / Q000175:diagnosis*; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor