Magnetic susceptibility-induced echo-time shifts: Is there a bias in age-related fMRI studies?

ABSTRACT:

Purpose

To evaluate the potential for bias in functional magnetic resonance imaging (fMRI) aging studies resulting from age-related differences in magnetic field distributions that can impact echo time and functional contrast.

Materials and methods

Magnetic field maps were taken on 31 younger adults (age: 22 ± 2.9 years) and 46 older adults (age: 66 ± 4.5 years) on a 3T scanner. Using the spatial gradients of the magnetic field map for each participant, an echo planar imaging (EPI) trajectory was simulated. The effective echo time, time at which the k-space trajectory is the closest to the center of k-space, was calculated. This was used to examine both within-subject and across-age-group differences in the effective echo time maps. The blood oxygenation level-dependent (BOL

SUBMITTER: Ngo GC 

PROVIDER: S-EPMC5156585 | biostudies-literature | 2017 Jan

REPOSITORIES: biostudies-literature