Flip Angle Effects on Resting State fMRI Studies

Yongquan Ye¹, Ewart Mark Haacke¹

Resting state fMRI reflects the BOLD signal induced by spontaneous neuronal activities at rest. rs-fMRI signal is especially sensitive to physiological noise, which often is the dominant source of noise. Recently it has been demonstrated that using a flip angle (FA) as low as 9 can reduce the relative weighting of physiological noise in BOLD signal while still sustaining sufficient BOLD contrast [1]. In this study, we will study how different flip angles affect rs-fMRI signal characteristics and the calculation of functional connectivity, and analyze the underlying mechanism of the origin of resting state signals.