title: Signal Intensities in Preoperative MRI Do Not Reflect Proliferative Activity in Meningioma.
abstract: BACKGROUND
  Identification of high-grade meningiomas in preoperative magnetic resonance imaging (MRI) is important for optimized surgical strategy and best possible resection. Numerous studies investigated subjectively determined morphological features as predictors of tumor biology in meningiomas. The aim of this study was to identify the predictive value of more reliable, quantitatively measured signal intensities in MRI for differentiation of high- and low-grade meningiomas and identification of meningiomas with high proliferation rates, respectively.
  
  
  METHODS
  Sixty-six patients (56 World Health Organization [WHO] grade I, 9 WHO grade II, and 1 WHO grade I) were included in the study. Preoperative MRI signal intensities (fluid-attenuated inversion recovery [FLAIR], T1 precontrast, and T1 postcontrast as genuine and normalized values) were correlated with Ki-67 expression in tissue sections of resected meningiomas. Differences between the groups (analysis of variance) and Spearman rho correlation were computed using SPSS 22.
  
  
  RESULTS
  Mean values of genuine signal intensities of meningiomas in FLAIR, T1 native, and T1 postcontrast were 323.9 ± 59, 332.8 ± 67.9, and 768.5 ± 165.3. Mean values of normalized (to the contralateral white matter) signal intensities of meningiomas in FLAIR, T1 native, and T1 postcontrast were 1.5 ± 0.3, 0.8 ± 0.1, and 1.9 ± 0.4. There was no significant correlation between MRI signal intensities and WHO grade or Ki-67 expression. Signal intensities did not differ significantly between WHO grade I and II/III meningiomas. Ki-67 expression was significantly increased in high-grade meningiomas compared with low-grade meningiomas (P < 0.01). Objectively measured values of MRI signal intensities (FLAIR, T1 precontrast, and T1 postcontrast enhancement) did not distinguish between high-grade and low-grade meningiomas. Furthermore, there was no association between MRI signal intensities and Ki-67 expression representing proliferative activity.
authors: Department of Neuroradiology, University Leipzig, Germany. Electronic address: stefan.Schob@medizin.uni-leipzig.de.
authors: Stefan
authors: S
authors: Schob
authors: Department of Neuropathology, University Leipzig, Germany.
authors: Clara
authors: C
authors: Frydrychowicz
authors: Department of Neuroradiology, University Leipzig, Germany.
authors: Matthias
authors: M
authors: Gawlitza
authors: Department of Radiology, McGill University Health Center, Montreal General Hospital.
authors: Lionel
authors: L
authors: Bure
authors: Department of Neurosurgery, University Leipzig, Germany.
authors: Matthias
authors: M
authors: Preuß
authors: Department of Neuroradiology, University Leipzig, Germany.
authors: Karl-Titus
authors: KT
authors: Hoffmann
authors: Department of Diagnostic and Interventional Radiology, University Leipzig, Germany.
authors: Alexey
authors: A
authors: Surov