title: The role of diffusion tensor imaging and dynamic susceptibility perfusion MRI in the evaluation of meningioma grade and subtype.
abstract: OBJECTIVE
  We prospectively investigated the relationship between diffusion tensor imaging (DTI), dynamic susceptibility perfusion (DSP) MRI metrics and grade, subtype and Ki-67 labelling index of meningiomas. MATERIALS AND ΜETHODS: Thirty-nine patients operated for meningioma were included in the study. DTI and DSP were performed within a week prior to surgical excision. Lesion/normal (L/N) tissue ratios and peritumoral area/normal tissue (P/N) ratios were calculated for the apparent diffusion coefficient (ADC), fractional anisotropy (FA) and relative cerebral blood volume (rCBV). In the tumor specimens Ki-67 antigen expression was evaluated by the MIB-1 immunostaining method.
  
  
  RESULTS
  There were 31 grade I, 7 grade II and one grade III meningiomas. Grade I meningiomas had a significantly lower L/N rCBV ratios than grade II/III meningiomas (median 5.1 vs 6.4, p=0.031). Grade I meningiomas revealed significantly lower P/N rCBV ratios than grade II/III meningiomas (median 0.78 vs 1.1, p=0.0077). Grade I meningiomas had significantly higher FA ratios than grade II/III meningiomas (median 0.5 vs 0.31, p=0.012). Meningiomas of meningothelial type had a significantly higher L/N rCBV ratio than other grade I meningiomas (median 5.4 vs 3.8, p=0.0136). There was no significant correlation between rCBV, ADC, FA and Ki-67 index.
  
  
  CONCLUSIONS
  Dynamic susceptibility perfusion indexes in lesion/normal and peritumoral/normal tissue ratios are useful for the differentiation grade I from grade II/III menigiomas. Meningothelial meningiomas showed higher lesion/normal tissue rCBV ratios from the other benign meningioma subtypes.
authors.affiliation: Department of Radiology, Medical School, University of Ioannina, Greece.
authors.forename: Anastasia
authors.initials: A
authors.lastname: Zikou
authors.affiliation: Department of Neurosurgery, Medical School, University of Ioannina, Greece. Electronic address: alexiougrg@yahoo.gr.
authors.forename: George A
authors.initials: GA
authors.lastname: Alexiou
authors.affiliation: Department of Pathology, Medical School, University of Ioannina, Greece.
authors.forename: Anna
authors.initials: A
authors.lastname: Goussia
authors.affiliation: Department of Radiology, Medical School, University of Ioannina, Greece.
authors.forename: Paraskevi
authors.initials: P
authors.lastname: Kosta
authors.affiliation: Department of Radiology, Medical School, University of Ioannina, Greece.
authors.forename: Vasileios
authors.initials: V
authors.lastname: Xydis
authors.affiliation: Department of Neurosurgery, Medical School, University of Ioannina, Greece.
authors.forename: Spyridon
authors.initials: S
authors.lastname: Voulgaris
authors.affiliation: Department of Neurology, Medical School, University of Ioannina, Greece.
authors.forename: Athanasios P
authors.initials: AP
authors.lastname: Kyritsis
authors.affiliation: Department of Radiology, Medical School, University of Ioannina, Greece.
authors.forename: Maria I
authors.initials: MI
authors.lastname: Argyropoulou
mesh_terms: D000328:Adult; D000368:Aged; D056324:Diffusion Tensor Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D019394:Ki-67 Antigen / Q000097:blood; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008577:Meningeal Neoplasms / Q000097:blood / Q000000981:diagnostic imaging*; D008579:Meningioma / Q000097:blood / Q000000981:diagnostic imaging*; D008875:Middle Aged; D060787:Neoplasm Grading; D055815:Young Adult
chemical_list: D019394:Ki-67 Antigen
keywords: Diffusion tensor imaging; MRI; Meningioma grades; Perfusion imaging