P3‐279: Reduced Supramarginal Gyrus Gray Matter Volume Associated with Cognitive Impairment in Alzheimer’S Disease: a 7‐tesla Mri Study

Ultra-high field 7 Tesla MRI offers superior signal-to-noise and spatial resolution relative to other non-invasive neuroimaging techniques and very few studies have investigated volumetric brain abnormalities in Alzheimer’s dementia (AD) using ultra-high field MRI. We aimed to detect brain volume changes in patients with AD compared to non-demented controls (NDC) using 7 Tesla MRI and investigate the association between brain volume alterations and cognitive measures in AD. Fourteen patients with mild to moderate AD and 12 age-matched NDC were scanned (structural MRI; sMRI) using a T1-weighted phase sensitive inversion recovery sequence on a 7T Philips Achieva system. Cognition was assessed using Mini Mental State Examination (MMSE) and Cambridge Cognitive Examination (CAMCOG). Pre-processing and statistical analysis of sMRI data was carried out in SPM8 using a voxel-based morphometric approach, covarying for total gray matter volume. AD and NDC groups did not differ in mean age and education. As expected, AD subjects scored lower on the MMSE (23 ±6) (p˂0.001). Gray matter volume was reduced in a small cluster including the right supramarginal gyrus extending to the post central gyrus in AD compared to NDC (uncorrected p<0.001) after correcting for total gray matter volume. Gray matter volume in this cluster significantly correlated with MMSE score (p=0.02; rho=0.468) and score on the perception subset (involving visual recognition) of CAMCOG (p=0.01, rho=0.798).