Nuclear overhauser enhancement mediated chemical exchange saturation transfer imaging at 7 Tesla in glioblastoma patients

Daniel Paech; Moritz Zaiss; Jan-Eric Meissner; Johannes Windschuh; Benedikt Wiestler; Peter Bachert; Jan Oliver Neumann; Philipp Kickingereder; Heinz-Peter Schlemmer; Wolfgang Wick; Armin Michael Nagel; Sabine Heiland; Mark Edward Ladd; Martin Bendszus; Alexander Radbruch

doi:10.1371/journal.pone.0104181

Nuclear overhauser enhancement mediated chemical exchange saturation transfer imaging at 7 Tesla in glioblastoma patients

PLoS One. 2014 Aug 11;9(8):e104181. doi: 10.1371/journal.pone.0104181. eCollection 2014.

Authors

Affiliations

¹ Department of Neuroradiology, University of Heidelberg Medical Center, Heidelberg, Germany; Neurooncologic Imaging, Department of Radiology, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany.
² Department of Medical Physics in Radiology, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany.
³ Department of Neurooncology, University of Heidelberg Medical Center, Heidelberg, Germany.
⁴ Department of Neurosurgery, University of Heidelberg Medical Center, Heidelberg, Germany.
⁵ Department of Neuroradiology, University of Heidelberg Medical Center, Heidelberg, Germany.
⁶ Department of Radiology, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany.

Abstract

Background and purpose: 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.

Patients and 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.

Conclusion: 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.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Contrast Media
Female
Glioblastoma / diagnosis*
Humans
Image Processing, Computer-Assisted
Magnetic Resonance Imaging / methods
Male
Middle Aged

Substances

Contrast Media

Grants and funding

This study was supported by a grant from the “Intramurales Förderprogramm” of the German Cancer Research Center. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.