  Cerebral arterial blood flow (CABF) can be investigated in few seconds
without any synchronization by Real-Time phase contrast. Significant changes in
CABF were found between expiration and inspiration during normal breathing of
healthy volunteers. Synopsis (100/100) Real-time phase contrast MRI has been
applied to investigate cerebral arterial blood flow (CABF) during normal
breathing of healthy volunteers. We developed a novel time-domain analysis
method to quantify the effect of normal breathing on several parameters of
CABF. We found the existence of a delay between the recorded respiratory signal
from the belt sensor and the breathing frequency component present in the
reconstructed arterial blood flows. During the expiratory, the mean flow rate
of CABF increased by 4.4$\pm$1.7%, stroke volume of CABF increased by
9.8$\pm$3.1% and the duration of the cardiac period of CABF increased by
8.1$\pm$3%.
