title: Nuclear overhauser enhancement mediated chemical exchange saturation transfer imaging at 7 Tesla in glioblastoma patients.
abstract: OBJECTIVE
  Nuclear Overhauser Enhancement (NOE) mediated chemical exchange saturation transfer (CEST) is a novel magnetic resonance imaging (MRI) technique on the basis of saturation transfer between exchanging protons of tissue proteins and bulk water. The purpose of this study was to evaluate and compare the information provided by three dimensional NOE mediated CEST at 7 Tesla (7T) and standard MRI in glioblastoma patients.
  
  
  METHODS
  Twelve patients with newly diagnosed histologically proven glioblastoma were enrolled in this prospective ethics committee-approved study. NOE mediated CEST contrast was acquired with a modified three-dimensional gradient-echo sequence and asymmetry analysis was conducted at 3.3 ppm (B1 = 0.7 µT) to calculate the magnetization transfer ratio asymmetry (MTR(asym)). Contrast enhanced T1 (CE-T1) and T2-weighted images were acquired at 3T and used for data co-registration and comparison.
  
  
  RESULTS
  Mean NOE mediated CEST signal based on MTR(asym) values over all patients was significantly increased (p<0.001) in CE-T1 tumor (-1.99 ± 1.22%), tumor necrosis (-1.36 ± 1.30%) and peritumoral CEST hyperintensities (PTCH) within T2 edema margins (-3.56 ± 1.24%) compared to contralateral normal appearing white matter (-8.38 ± 1.19%). In CE-T1 tumor (p = 0.015) and tumor necrosis (p<0.001) mean MTR(asym) values were significantly higher than in PTCH. Extent of the surrounding tumor hyperintensity was smaller in eight out of 12 patients on CEST than on T2-weighted images, while four displayed at equal size. In all patients, isolated high intensity regions (0.40 ± 2.21%) displayed on CEST within the CE-T1 tumor that were not discernible on CE-T1 or T2-weighted images.
  
  
  CONCLUSIONS
  NOE mediated CEST Imaging at 7 T provides additional information on the structure of peritumoral hyperintensities in glioblastoma and displays isolated high intensity regions within the CE-T1 tumor that cannot be acquired on CE-T1 or T2-weighted images. Further research is needed to determine the origin of NOE mediated CEST and possible clinical applications such as therapy assessment or biopsy planning.
authors.affiliation: Department of Neuroradiology, University of Heidelberg Medical Center, Heidelberg, Germany; Neurooncologic Imaging, Department of Radiology, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Paech
authors.affiliation: Department of Medical Physics in Radiology, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany.
authors.forename: Moritz
authors.initials: M
authors.lastname: Zaiss
authors.affiliation: Department of Medical Physics in Radiology, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany.
authors.forename: Jan-Eric
authors.initials: JE
authors.lastname: Meissner
authors.affiliation: Department of Medical Physics in Radiology, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Windschuh
authors.affiliation: Department of Neurooncology, University of Heidelberg Medical Center, Heidelberg, Germany.
authors.forename: Benedikt
authors.initials: B
authors.lastname: Wiestler
authors.affiliation: Department of Medical Physics in Radiology, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Bachert
authors.affiliation: Department of Neurosurgery, University of Heidelberg Medical Center, Heidelberg, Germany.
authors.forename: Jan Oliver
authors.initials: JO
authors.lastname: Neumann
authors.affiliation: Department of Neuroradiology, University of Heidelberg Medical Center, Heidelberg, Germany.
authors.forename: Philipp
authors.initials: P
authors.lastname: Kickingereder
authors.affiliation: Department of Radiology, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany.
authors.forename: Heinz-Peter
authors.initials: HP
authors.lastname: Schlemmer
authors.affiliation: Department of Neurooncology, University of Heidelberg Medical Center, Heidelberg, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Wick
authors.affiliation: Department of Medical Physics in Radiology, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany.
authors.forename: Armin Michael
authors.initials: AM
authors.lastname: Nagel
authors.affiliation: Department of Neuroradiology, University of Heidelberg Medical Center, Heidelberg, Germany.
authors.forename: Sabine
authors.initials: S
authors.lastname: Heiland
authors.affiliation: Department of Medical Physics in Radiology, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany.
authors.forename: Mark Edward
authors.initials: ME
authors.lastname: Ladd
authors.affiliation: Department of Neuroradiology, University of Heidelberg Medical Center, Heidelberg, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Bendszus
authors.affiliation: Department of Neuroradiology, University of Heidelberg Medical Center, Heidelberg, Germany; Neurooncologic Imaging, Department of Radiology, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Radbruch
mesh_terms: D003287:Contrast Media; D005260:Female; D005909:Glioblastoma / Q000175:diagnosis*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged
chemical_list: D003287:Contrast Media
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