Multimodal Neuroimaging of Brain Structure and Function

A 3T Siemens Tim Trio MR scanner with a Siemens 12-channel head coil (Siemens, Munich, Germany) was used for obtaining MRI scans in 2006–07. Image acquisition and analyses have been previously described.^{21 (link)} Magnetization-prepared rapid gradient echo (MPRAGE) images were acquired to obtain GMV and white matter hyperintensities (WMH) volume. Atrophy of total brain was computed as the ratio of GMV of total brain by intracranial volume. Gray matter volume of regions of interest (ROI) were defined a priori, and included the medial temporal lobe (hippocampus, parahippocampus, entorhinal cortex), basal ganglia (caudate, putamen, pallidum, thalamus), posterior parietal cortex (superior and inferior parietal lobule), cingulate cortex (anterior, middle, and posterior portion), and cerebellum, based on previous literature demonstrating regional associations with mobility and cognitive function.^{22 (link)–24 (link)} The neuroanatomical boundaries of these regions have been previously published.²⁵ WMH volume was for total brain quantified from T2-weighted fluid-attenuated inversion recovery images with a semi-automated method, as previously described.^{26 (link)}