A newly developed silent mode MRI and a sequence allowed us to capture the participants’ brain structure in less than 30 s (19 (link)). Consequently, with the help of an MRI-compatible video presentation system and an MRI-compatible headphone system, we were able to conduct MRI without sedation for the other 21 children. The following methods for MR image acquisition have been described before (11 (link)). A 1.5-T MRI scanner (SIGNA Explorer; GE Healthcare, United States) was used to collect structural brain images from all participants. The three-dimensional high-resolution T1-weighted gradient-echo and Silenz pulse sequence images were used as an anatomical reference. The imaging parameters were as follows: TR = 435.68 ms, TE = 0.024 ms, flip angle = 7°, FOV = 220 mm, matrix size = 256 × 256 pixels, slice thickness = 1.7 mm, total of 130 transaxial images.
For these 21 participants, we co-registered the MEG and their own MR images following the marker locations. The markers for MEG and MRI were the frontal midline, parietal, and bilateral mastoid processes. For the MEG, we used four coils to generate a magnetic field. For MRI, we used four pieces of lipid capsule as markers. Furthermore, we identified points on the mastoid processes, nasion, and skull surface visually on MRI. Approximately 15–25 points were depicted for each participant.
For these 21 participants, we co-registered the MEG and their own MR images following the marker locations. The markers for MEG and MRI were the frontal midline, parietal, and bilateral mastoid processes. For the MEG, we used four coils to generate a magnetic field. For MRI, we used four pieces of lipid capsule as markers. Furthermore, we identified points on the mastoid processes, nasion, and skull surface visually on MRI. Approximately 15–25 points were depicted for each participant.
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