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

Paech D, Zaiss M, Meissner JE, Windschuh J, Wiestler B, Bachert P, Neumann JO, Kickingereder P, Schlemmer HP, Wick W, Nagel AM, Heiland S, Ladd ME, Bendszus M, Radbruch A - PLoS ONE (2014)

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Neuroradiology, University of Heidelberg Medical Center, Heidelberg, Germany; Neurooncologic Imaging, 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.

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Boxplots of MTRAsym quantification from regions of interest (ROI) analysis over all glioblastoma patients.Boxplots of mean MTRAsym values on CEST contrast over all patients (N = 12). Overall mean MTRasym (red stars) and outliers (red crosses) are additionally illustrated. MTRasym values in all tumor areas (CE-T1 tumor, isolated CEST HIR in CE-T1 tumor, tumor necrosis) and CSF are significantly higher than in CLNAWM (p<0.001). Average signal intensity in PTCH within T2 edema margins is significantly higher (p<0.001) than in CLNAWM and significantly lower (p = 0.015) than in CE-T1 tumor and tumor necrosis (p<0.001). The whiskers of the boxplot for isolated CEST HIR indicate a high variance within this group, which is due to smaller ROI size and the fact that the isolated CEST HIR were visually selected relative to surrounding signal intensity in CE-T1 tumor.
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pone-0104181-g004: Boxplots of MTRAsym quantification from regions of interest (ROI) analysis over all glioblastoma patients.Boxplots of mean MTRAsym values on CEST contrast over all patients (N = 12). Overall mean MTRasym (red stars) and outliers (red crosses) are additionally illustrated. MTRasym values in all tumor areas (CE-T1 tumor, isolated CEST HIR in CE-T1 tumor, tumor necrosis) and CSF are significantly higher than in CLNAWM (p<0.001). Average signal intensity in PTCH within T2 edema margins is significantly higher (p<0.001) than in CLNAWM and significantly lower (p = 0.015) than in CE-T1 tumor and tumor necrosis (p<0.001). The whiskers of the boxplot for isolated CEST HIR indicate a high variance within this group, which is due to smaller ROI size and the fact that the isolated CEST HIR were visually selected relative to surrounding signal intensity in CE-T1 tumor.

Mentions: The analysis of variance (ANOVA) with repeated measures was p<0.001 for statistically significant differences among the six groups by ROI analysis. Post hoc Holm-Sidac pairwise multiple comparisons showed that average MTRasym of CE-T1 tumor, isolated CEST HIR within the CE-T1 tumor, tumor necrosis, PTCH within T2 edema margins and CSF were all significantly higher than MTRasym of CLNAWM (p<0.001). Mean MTRasym in PTCH within T2 edema margins was significantly increased (p<0.001) compared to CLNAWM and significantly lower than in CE-T1 tumor (p = 0.015) and tumor necrosis (p<0.001). Average MTRasym in isolated CEST HIR within CE-T1 tumor was significantly higher than in the whole CE-T1 tumor (p<0.001) and PTCH within T2 edema margins (p<0.001). In tumor necrosis, MTRasym was significantly lower than in isolated CEST HIR within CE-T1 tumor (p = 0.007) and CSF (p = 0.001) but not significantly different compared to CE-T1 tumor (p = 0.42) (Fig. 4).


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

Paech D, Zaiss M, Meissner JE, Windschuh J, Wiestler B, Bachert P, Neumann JO, Kickingereder P, Schlemmer HP, Wick W, Nagel AM, Heiland S, Ladd ME, Bendszus M, Radbruch A - PLoS ONE (2014)

Boxplots of MTRAsym quantification from regions of interest (ROI) analysis over all glioblastoma patients.Boxplots of mean MTRAsym values on CEST contrast over all patients (N = 12). Overall mean MTRasym (red stars) and outliers (red crosses) are additionally illustrated. MTRasym values in all tumor areas (CE-T1 tumor, isolated CEST HIR in CE-T1 tumor, tumor necrosis) and CSF are significantly higher than in CLNAWM (p<0.001). Average signal intensity in PTCH within T2 edema margins is significantly higher (p<0.001) than in CLNAWM and significantly lower (p = 0.015) than in CE-T1 tumor and tumor necrosis (p<0.001). The whiskers of the boxplot for isolated CEST HIR indicate a high variance within this group, which is due to smaller ROI size and the fact that the isolated CEST HIR were visually selected relative to surrounding signal intensity in CE-T1 tumor.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4128651&req=5

pone-0104181-g004: Boxplots of MTRAsym quantification from regions of interest (ROI) analysis over all glioblastoma patients.Boxplots of mean MTRAsym values on CEST contrast over all patients (N = 12). Overall mean MTRasym (red stars) and outliers (red crosses) are additionally illustrated. MTRasym values in all tumor areas (CE-T1 tumor, isolated CEST HIR in CE-T1 tumor, tumor necrosis) and CSF are significantly higher than in CLNAWM (p<0.001). Average signal intensity in PTCH within T2 edema margins is significantly higher (p<0.001) than in CLNAWM and significantly lower (p = 0.015) than in CE-T1 tumor and tumor necrosis (p<0.001). The whiskers of the boxplot for isolated CEST HIR indicate a high variance within this group, which is due to smaller ROI size and the fact that the isolated CEST HIR were visually selected relative to surrounding signal intensity in CE-T1 tumor.
Mentions: The analysis of variance (ANOVA) with repeated measures was p<0.001 for statistically significant differences among the six groups by ROI analysis. Post hoc Holm-Sidac pairwise multiple comparisons showed that average MTRasym of CE-T1 tumor, isolated CEST HIR within the CE-T1 tumor, tumor necrosis, PTCH within T2 edema margins and CSF were all significantly higher than MTRasym of CLNAWM (p<0.001). Mean MTRasym in PTCH within T2 edema margins was significantly increased (p<0.001) compared to CLNAWM and significantly lower than in CE-T1 tumor (p = 0.015) and tumor necrosis (p<0.001). Average MTRasym in isolated CEST HIR within CE-T1 tumor was significantly higher than in the whole CE-T1 tumor (p<0.001) and PTCH within T2 edema margins (p<0.001). In tumor necrosis, MTRasym was significantly lower than in isolated CEST HIR within CE-T1 tumor (p = 0.007) and CSF (p = 0.001) but not significantly different compared to CE-T1 tumor (p = 0.42) (Fig. 4).

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Neuroradiology, University of Heidelberg Medical Center, Heidelberg, Germany; Neurooncologic Imaging, 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.

Show MeSH
Related in: MedlinePlus