Three-dimensional Chemical Exchange Saturation Transfer (CEST) Imaging at 7 Tesla in Glioblastoma Patients

Zielsetzung:

To evaluate the additional information provided by three dimensional chemical exchange saturation transfer (CEST) magnetic resonance (MR) imaging in newly diagnosed patients with glioblastoma multiforme (GBM) at 7 Tesla (7T) and its diagnostic benefits, compared to standard MR imaging.

Material und Methodik:

11 Patients with histologically proven glioblastoma were enrolled in this prospective study with the approval of the local ethics committee after written informed consent was obtained. CEST contrast was obtained with a modified three-dimensional gradient-echo sequence (˜10 min 30 s) and a 24-channel head coil by asymmetry-analysis at 3.33 ppm. B1 was set at 0.7µT where CEST effects are predominantly mediated by Nuclear Overhauser Enhancement (NOE) of intracellular mobile proteins. Contrast enhanced T1 (ce-T1) weighted and T2-weighted sequences at 3T were used for data co-registration.

Ergebnisse:

CEST effect in ce-T1 regions was significantly higher than in the surrounding edema (p < 0.001) and in contralateral white matter (p< 0.001). CEST effect in the edema was significantly higher (p < 0.001) than in the contralateral white matter. Three dimensional edema extensions in 9 out of 11 patients on CEST were smaller than on T2 weighted images (2 out of 11 equal size). Significant hot spots on CEST displayed in contrast enhancing tumor regions in all patients (p=0.002).

Schlussfolgerungen:

CEST Imaging at 7 Tesla provides additional information on tumor infiltration, edema substructure and hot spots that do not display on ce-T1 or T2-weighted images.

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