Chisato Suzuki1, Kenichi Ueno1, R. Allen Waggoner2, Kang Cheng1, 2
1fMRI Support Unit, RIKEN-Brain Science Institute, Wako-shi, Saitama, Japan; 2Laboratory for Cognitive Brain Mapping, RIKEN-Brain Science Institute, Wako-shi, Saitama, Japan
Cardiac artifacts are a major contributor to noise in BOLD studies of deep brain structures. The aim of this study was to evaluate the effect of this artifact with MPRAGE and EPI images. By reordering the k-space data based on the cardiac cycle timing, we revealed signal components synchronized to cardiac pulses. In contrast to EPI data that showed widely distributed artifacts in and around the brainstem, no heartbeat-synchronized signal was found in T1W data. These results suggest that rather than physical motion the main component of the artifacts is from sources such as CSF flow and the vessel pulsation.