title: Imaging of adult astrocytic brain tumours with 7 T MRI: preliminary results.
abstract: OBJECTIVE
  In this study tumour vascularity and necrosis of intracranial astrocytomas were compared using 7 T and 1.5 T magnetic resonance imaging (MRI).
  
  
  METHODS
  Fifteen patients with histologically proven astrocytomas (WHO grades II-IV) were prospectively examined at 1.5 T (Magnetom Espree or Sonata) and 7 T (Magnetom 7 T, Siemens, Erlangen, Germany) with T2*-w (weighted), T1-w with (only a subset of five patients at 7 T) and without contrast medium, T2-w and proton-density (PD)-w MRI. Clinically used 1.5 T sequences were adapted to 7 T. Histological findings and T2*-w MR images at both field strengths were compared for the presence of assumed tumour microvascularity and necrosis. Two diffusely infiltrating astrocytomas, four anaplastic astrocytomas and nine glioblastomas were included.
  
  
  RESULTS
  T2*-w images depicted susceptibility patterns representing presumed tumour microvascularity in 8 out of 15 (53%) gliomas at 7 T compared with 5 out of 15 (33%) gliomas at 1.5 T. Compared with 1.5 T MRI three additional necrotic tumour areas were depicted only on 7 T T2- and T2*-w images of one glioblastoma. On T1-w MR images, contrast enhancement of five out of five glioblastomas was similar at both field strengths.
  
  
  CONCLUSIONS
  7 T gradient-echo sequences provide excellent image contrast of presumed microvasculature and necrosis in astrocytomas.
authors.affiliation: Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Hufelandstrasse 55, 45147 Essen, Germany. christoph.moenninghoff@uk-essen.de
authors.forename: Christoph
authors.initials: C
authors.lastname: Moenninghoff
authors.forename: Stefan
authors.initials: S
authors.lastname: Maderwald
authors.forename: Jens M
authors.initials: JM
authors.lastname: Theysohn
authors.forename: Oliver
authors.initials: O
authors.lastname: Kraff
authors.forename: Mark E
authors.initials: ME
authors.lastname: Ladd
authors.forename: Nicolai
authors.initials: N
authors.lastname: El Hindy
authors.forename: Johannes
authors.initials: J
authors.lastname: van de Nes
authors.forename: Michael
authors.initials: M
authors.lastname: Forsting
authors.forename: Isabel
authors.initials: I
authors.lastname: Wanke
mesh_terms: D000328:Adult; D000368:Aged; D001254:Astrocytoma / Q000098:blood supply / Q000473:pathology*; D001932:Brain Neoplasms / Q000098:blood supply / Q000473:pathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009389:Neovascularization, Pathologic / Q000473:pathology*; D010865:Pilot Projects; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity