3t tim trio

Scans were performed with a Siemens TIM Trio 3T MRI system equipped with a standard 12 channel head coil (Siemens Magnetom Trio TIM, Erlangen, Germany). An echo-planar imaging (EPI) sequence was used with 432 T2*-weighted images recorded per run (TR = 2000 ms; TE = 30 ms; flip angle = 90°; FOV = 192 × 192 mm²; matrix size = 64 × 64; voxel size = 3 × 3 × 3 mm³; interslice skip = 0.99 mm; Slices = 32). T1-weighted images were acquired with a total of 176 slices at a thickness of 1 mm and in-plane resolution of 0.98 × 0.98 mm² (TR = 1900 ms; TE = 2.52 ms; flip angle = 9°; FOV = 250 mm² × 250 mm²).

This is a retrospective compilation of data for >1,000 participants that were collected across several ongoing projects through the WUSTL Knight ADRC over the course of 30 years. Participants include n = 609 cognitively normal adults and n=489 individuals at with MCI or dementia ranging in age from 42 to 95 years. Using Clinical Dementia Rating scale (CDR) scores, we classified participants as healthy control (HC), stable MCI, progressive MCI or AD, as detailed in Table 1. Follow-up CDR scores used to define MCI status were from at least 3 years after baseline assessments. We excluded scans which did not pass quality standards after pre-processing pipeline. MPRAGE was collected on Siemens TIM Trio 3T (TR = 2,400 ms, TE = 3.08 ms, TI = 1, flip angle = 8°, FOV = 256 × 256, voxel size = 1 mm isotropic). Further information can be found at https://www.oasis-brains.org/.

Blood oxygenation level dependent (BOLD) contrast functional images were acquired with echo-planar T2^∗-weighted (EPI) imaging using a Siemens Tim Trio 3T magnetic resonance imaging system with a 12 channel head coil. Each image volume comprised 25 3mm thick slices (interslice gap: 0.75 mm; inplane resolution: 2.4 × 2.4 mm; flip angle: 74∘; echo time: 0.54 ms; bandwidth: 2126 Hz; repetition time, TR: 2.0 s; TE: 35 ms). Slice acquisition was descending and axial oblique, angled to avoid the eyeballs. Data were acquired in two scanning runs of approximately 7 min. The first five volumes of each run were discarded to allow for T1 equilibration effects. These acquisition parameters were chosen to minimize voxel size while covering all the brain regions of interest (ROIs). In some subjects, cerebellum and part of motor cortex was not covered by our slice prescription. In order to aid co-registration, an additional eight EPI volumes were acquired using the same parameters as the task data but with an increased number of slices and adjusted TR.

Structural images were collected including full magnetization prepared gradient‐echo (MPRAGE) using a Siemens Tim Trio 3T‐scanner with a 32‐channel head coil using a T1 weighted MPRAGE sequence (176 sagittal slices, 9 minute scans; repetition time (TR) = 2,500 ms; TE = 4.77 ms; inversion time = 1,100 ms; acquisition matrix = 256 × 256 × 176; flip angle = 7°; voxel size 1 × 1 × 1 mm). Scanning took place at The Wolfson Brain Imaging Centre at the University of Cambridge.
Structural data was processed with Statistical Parametric Mapping (SPM8; http://www.fil.ion.ucl.ac.uk/spm) (Wellcome Trust Centre for Neuroimaging, London, UK). Anatomical images were manually re‐oriented, placing the origin at the anterior commissure. Images were segmented (using New Segment for SPM) into GM, WM and cerebrospinal fluid (CSF) based on standard tissue probability maps for each tissue type. The three tissue class volumes were summed to produce estimated total intracranial volume. A custom template was created using DARTEL [Ashburner, 2007], which defines the parameters necessary to fit each individuals' native GM image to a common space, in an iterative manner. This DARTEL template was then registered to the tissue probability maps with affine transformations, bringing images into MNI space. Images were smoothed spatially with a full width at half maximum kernel of 8 mm³.