Achieva 7t mr system

This study was performed using an actively shielded Philips Achieva 7T MR system (Philips Healthcare, Best, the Netherlands) equipped with a two-channel volume transmit head coil with a 32-channel receiver array (Nova Medical Inc., Burlington, MA, USA). The scanner was installed at the Danish Research Centre for Magnetic Resonance, Copenhagen University Hospital Hvidovre. We used 3D based B₁⁺ scaling, which greatly reduced the spatially varying inhomogeneities [26 ]. This improved tumour–tissue contrast, particularly in the temporal regions, which, in turn, provided a better basis for the placement of MRS voxels on 3D FLAIR images (see Section 2.3). On top of the B₁⁺ scaling, we applied dielectric pads (size: 19 cm × 19 cm, Multiwave Technologies Ltd., Geneva, Switzerland) on both sides of the head to further minimize B₁⁺-induced inhomogeneities. We also used interleaved volumetric fat-navigator-based prospective motion correction for the structural sequences [27 (link)], which reduced the need for re-scans and thus also patient discomfort caused by prolonged scan duration.