A comparison of signal instability in 2D and 3D EPI resting-state fMRI.

摘要: Spatiotemporally structured noise, such as physiological is a potential source of artifacts in functional magnetic resonance imaging (fMRI) and the main limiting factor for detection small blood oxygen level-dependent (BOLD) signal variations. fMRI was employed to detect low-frequency BOLD fluctuations, which are thought be related spontaneous neuronal activity resting human brain. The sensitivity that is, variations non-BOLD origin, investigated two- (2D) three-dimensional (3D) techniques. Incomplete relaxation between subsequent scans increases level temporally spatially correlated originating from and/or systemic noise. Although inflow effects suspected reduced 3D echo-planar (EPI) compared with multi-slice 2D EPI, noise higher technique. experiments significantly increased by instabilities transverse steady-state magnetization repetition time order T(2). By implementing radiofrequency spoiling, temporal fluctuations erroneous inter-regional correlation connectivity maps were diminished present data sets acquired EPI.