Reproducibility of T2∗ mapping in the human cerebral cortex in vivo at 7 tesla MRI

Abstract

Background To assess the test-retest reproducibility of cortical mapping of T2∗ relaxation rates at 7 Tesla (T) MRI. T2∗ maps have been used for studying cortical myelo-architecture patterns in vivo and for characterizing conditions associated with changes in iron and/or myelin concentration. Methods T2∗ maps were calculated from 7T multi-echo T2∗-weighted images acquired during separate scanning sessions on 8 healthy subjects. The reproducibility of surface-based cortical T2∗ mapping was assessed at different depths of the cortex; from pial surface (0% depth) towards gray/white matter boundary (100% depth), across cortical regions and hemispheres, using coefficients of variation (COVs-=-SD/mean) between each couple (scan-rescan) of average T2∗ measurements. Results Average cortical T2∗ was significantly different among 25%, 50%, and 75% depths (analysis of variance, P-