Skyra mri system

Images were acquired on a 3.0 Tesla Skyra MRI system (Siemens, Erlangen, Germany). T₂*-weighted gradient-echo echo-planar images (repetition time: 2000 ms, echo time 30 ms, 29 ascending slices, distance factor 20%, voxel size, 2 × 2 × 2 mm, flip angle 80 degrees, field of view 59 mm) were acquired using a 32-channel head coil. We chose to focus on the visual, middle/superior temporal and middle/frontal areas and we did not include the parietal, inferior temporal and motor cortices, guided by the results from our previous study8 and our hypotheses. The reason that we could not include the whole brain was a trade-off between voxel size, TR, and the number of slices, since we planned to do MVPA analyses on our fMRI data, which benefits from smaller voxel size. However, because decoding of motion direction on the basis of the activity patterns obtained during the motion localizer data was unreliable, we did not perform any further MVPA analyses. A high-resolution anatomical image was collected using a T₁-weighted magnetization prepared rapid gradient-echo sequence (repetition time: 2300 ms, echo time 3.03 ms, voxel size 1 × 1 × 1 mm).

All patients underwent MRI on a 3.0T Siemens Skyra MRI system (Siemens, Erlangen, Germany). The imaging protocol included DTI, fluid attenuation inversion recovery imaging, gradient recalled echo, MR angiography, and DSC perfusion imaging.
DTI was acquired using single-shot spin-echo echo-planar imaging (repetition time/echo time, 5500/82 ms; field of view, 22×22 cm; matrix, 128 mm; slices, 40×3 mm; voxel size, 1.5×1.5×3 mm). Diffusion gradients were applied along 20 noncollinear directions with a b value of 1000 s/mm² resulting in a 5-minute acquisition time. A generalized partial parallel acquisition^{16 (link)} technique with acceleration factor of 3 was used.
DSC perfusion was performed using a single-shot gradient-echo echo-planar imaging sequence with the following parameters: repetition time/echo time, 1450/22 ms, FA=90°; field of view, 22×22 cm; matrix, 128×128 mm, 30×4 mm slices; generalized partial parallel acquisition, 3). A total of 60 repetitions were acquired after intravenous injection of 0.1 mmol/kg of gadolinium contrast agent at a rate of 5 mL/s.

Whole brain imaging was performed on a 3 T Siemens Skyra MRI system (Siemens Medical Systems, Erlangen, Germany) using a 32-channel head coil. T2*-weighted functional images were acquired using a single shot gradient echo planar imaging (EPI) sequence (TR = 1850 ms, TE = 30 ms, flip angle = 90°, 32 transversal slices, 3.5 mm isomorphic with distance factor 20%, interleaved slice ordering). Head motion was corrected online. The first two volumes of each scan were discarded in order to allow for T1 equilibration effects. Head motion was restricted using firm padding surrounding participant’s heads. Visual stimuli were presented using the software Presentation (Neurobehavioral Systems, Albany, CA) onto a computer screen and viewed through a mirror attached to the head coil.

Functional and anatomic images were collected on a 3T Skyra MRI system (Siemens, Munich, Germany), using a 32-channel head-coil. Functional images were acquired using a T2*-weighted multiband-3 sequence to acquire partial brain volumes aligned to maximize coverage of early visual areas (TR/TE = 825/32 ms, 27 slices, voxel size = 2 mm isotropic, 55° flip angle, A/P phase encoding direction). Anatomic images were acquired with a T1-weighted MP-RAGE (GRAPPA acceleration factor = 2, TR/TE = 2300/3.03 ms, voxel size 1 mm isotropic, 8° flip angle).

The functional images were acquired with a 3T Skyra MRI system (Siemens, Erlangen, Germany) using a continuous T2*-weighted gradient-echo EPI sequence (29 horizontal slices, FA = 80 degrees, FOV = 192 × 192 × 59 mm, voxel size = 2 × 2 × 2 mm, TR/TE = 2000/30 ms). The structural image was collected using a T1-weighted MP-Rage sequence (FA = 8 degrees, FOV = 192 × 256 × 256 mm, voxel size 1 × 1 × 1, TR = 2300 ms).