Brain Structure Analysis via MRI

The brain structure images were captured using the Magnetom Verio 3.0 T scanner (Siemens, Munich, Germany). The rapid gradient echo (MPRAGE) sequence parameters prepared by T1-weighted THREE-DIMENSIONAL magnetization were as follows: TR = 2,300 ms, TE = 2.98 ms, matrix size = 240 × 256; flip angle of 9 degrees, slice thickness = 1.2 mm, field of view (FOV) = 240 × 256 mm. Volume data was evaluated by automated procedures, as described by Wolz et al.^{34 (link)}. Based on our previous research^{35 (link),36 (link)} and the research hypothesis in the introduction, volume and asymmetry of amygdala, and brain size index were extracted for each subject (using FreeSurfer). In addition, to evaluate the effect of left–right difference, the asymmetry index was calculated by the formula [right volume-left volume]/[Total volume] × 100%. Quality control is done by overlapping output parcellations on FreeSurfer’s templates and performing visual evaluations to ensure registration and parcell quality.