Vision 1.5 t

Structural brain magnetic resonance imaging (MRI) was obtained through a Siemens Trio 3.0 T or Vision 1.5-T imaging system. The image processing frameworks Free-surfer software (version 4.3 and 5.1) were applied to estimate the regional volume based on MRI images [26 (link)]. The whole brain volume and several regional brain volumes (ventricles, hippocampus, middle temporal lobe, fusiform gyrus, entorhinal cortex) were utilized in our analyses.

This dataset consisted of 314 healthy adults (196 females), aged 18–94 (see Fig. 2), from the Open Access Series of Imaging Studies (OASIS) cross-sectional dataset (http://www.oasis-brains.org) [80 (link)]. Participants were recruited from a database of individuals who had (a) previously participated in MRI studies at Washington University, (b) were part of the Washington University Community, or (c) were from the longitudinal pool of the Washington University Alzheimer Disease Research Center. Participants were screened for neurological and psychiatric issues; the Mini-Mental State Examination (MMSE) and Clinical Dementia Rating (CDR) were administered to participants aged 60 and older. To only include healthy adults, participants with a CDR above zero were excluded; all remaining participants scored 25 or above on the MMSE. Multiple T1 volumes were acquired using a Siemens Vision 1.5 T with a MPRAGE sequence; only the first volume was used here. Scan parameters were: TR $=$ 9.7 ms; TE $=$ 4.0 ms; $\text{flip angle}={10}^{\circ }$ ; $\text{voxel size}=1.25\times 1\times 1\text{mm}$ . Age-related comparisons for volumetric and fractal dimensionality measures from the OASIS dataset were previously reported [7 (link), 81 (link), 82 (link)].1