8 channel surface coil

Participants were scanned at the Lucas Imaging Center at Stanford University in a 3T GE scanner equipped with an 8-channel surface coil. We acquired 32 slices at a resolution of 3.125 × 3.125 × 3mm mm using a two-shot T2*-sensitive spiral (Glover, 1999 (link)) acquisition sequence (FOV = 200 mm; TR=2 seconds, TE=30 ms, and flip angle = 76°).

MRI and proton MRS were acquired as described (4, also see Supplemental Methods). Briefly, data were collected at 3T (GE Signa) with an 8-channel surface coil. Whole-brain T1-weighted MRI was obtained using 3D spoiled gradient-recall with 0.98×0.98×1.0 mm³ voxels. The T1 was used to prescribe MPCSI and to segment the brain into gray and white matter. An in-plane high-resolution “localizer” MRI was acquired in register with MPCSI with voxels 0.98×0.98×10 mm³. The localizer was used to normalize MPCSI data into a common template brain space. MRS was acquired in 6 axial-oblique slabs parallel to the anterior commissure-posterior commissure plane (AC-PC): one slab below, one containing and four above the AC-PC (Figure 1). We acquired water-suppressed MPCSI with TR/TE=2800/144 ms, voxels 10×10×10 mm³ and outer-volume lipid suppression.

All MR data were acquired on a GE Signa 3 Tesla whole body scanner (Milwaukee, WI) equipped with an 8-channel surface coil for parallel imaging. Head positioning was standardized using cantho-meatal landmarks. No sedation was used at any time during the study. Participant faces were monitored during the scan using a video camera. A research assistant was present throughout the scan and confirmed that the participant was awake and resting quietly at the start and completion of each sequence. If the participant showed signs of anxiety or hyperventilation, the scan was immediately terminated and the data were not included in the study.