T1-weighted structural images of the whole brain were acquired on the first scan session using a three-dimensional magnetization-prepared rapid acquisition gradient echo pulse sequence (repetition time (TR) 1620 ms; echo time (TE) 3.09 ms; inversion time 950 ms; voxel size 1 × 1 × 1 mm; matrix size 190 × 263 × 165).
A field map was also acquired at each scan session (TR 1200 ms; TE1 4.06 ms; TE2 6.52 ms; flip angle 60° voxel size 3.4 × 3.4 × 4.0 mm; field of view 220 mm; matrix size 64 × 64 × 52) to correct geometric distortion caused by magnetic field inhomogeneity.
3D emission data was then acquired at 3 min per bed position (PET reconstruction: 4 iterations; subset 8; Gaussian pre-filter; FWHM 5 mm; matrix size 168 × 168; zoom 1).
CT imaging first consisted of an unenhanced low-dose CT (40 mAs/120 kV; detector collimation, 16 × 1.5 mm) reconstructed with a slice thickness of 5 mm (matrix size, 512 × 512; voxel size, 1.4 × 1.4 × 5.0 mm).
The scanning session included conventional anatomical MR images (T1-WI, T2-WI, T2-FLAIR), 3D spoiled gradient echo (SPGR) sequence (FOV- 250 mm, matrix size- 256×256, voxel size 0.98×0.98×1) and functional T2*-weighted images (FOV = 200 mm, matrix size- 64×64, voxel size-3×3×4, TR/TE = 2000/35, Slice thickness = 4 mm, 30 axial slices without gap).
Functional images were collected using a gradient echo-planar imaging sequence (TR: 2000 ms; TE: 30 ms; flip angle: 90°; field-of-view: 192×192 mm; matrix size: 64×64).
Image parameters were as follows: FOV 250×250 mm, matrix size 256×128, 3 slices per orientation, slice thickness 8 mm, TR/TE 15/5 ms, excitation flip angle 40° and bandwidth 180 Hz/Px.
We collected 1250 T2*-weighted, gradient echo EPI scans (slice thickness: 2.0 mm; inter-slice gap: 1.0 mm; matrix size: 128×128; field of view: 230×230 mm; echo time: 33 ms; repetition time: 2700 ms).
The characteristics of this sequence were: 252 volumes, 32 slices, 3×3×3 mm3, gap thickness 0.75 mm, matrix size 64×64, FOV 192×192 mm2, TR/TE 1980ms/30ms.
Contrast-enhanced T1-weighted spin-echo images were acquired with the following parameters: Repetition time/echo time (TR/TE) = 85/3.2 ms, field of view (FOV) = 30 mm, matrix size = 128×64, slice thickness = 1 mm, 13 slices and number of scans = 2.
Diffusion-weighted images were acquired using a spin-echo sequence, with motion correction using a navigator echo and gradient waveforms sensitive to isotropic diffusion, with the following parameters: TR/TE = 4000/47 ms, FOV = 30 mm, matrix size = 128×64, slice thickness = 1 mm and b-values (diffusion weighting) of 120 and 1200 s/mm2.
